摘要:

426 REVIEWS INKS : THEIR COMPOSITION AND MANUFACTURE. By C. AINSWORTH MITCHELL, D.Sc., F.I.C. Fourth Edition. Pp. xi + 408. London: Charles Grihn tt Co., Ltd. 1937. Price 12s. 6d. net. This, the fourth edition of the standard and, indeed, so far as the reviewer’s knowledge goes, the only text-book on the subject in the language, bridges L gap of 13 years. The author, pre-eminent in his particular sphere, needs little more introduction to the world of technical industry than he does in his official capicity to readers of THE ANALYST, while his reputation in forensic science in all that appertains to handwriting is international. The chemistry of ink, difficult as it is and at times not a little obscure, hcl- riot developed markedly in the interval since 1924; but what progress has been made is covered by Dr.Mitchell in this edition in a very thorough manner. He has found it necessary to enlarge his work to the extent of some 20 per cent. and, in addition, to rewrite a large portion. The arrangement of the book follows the lines of previous editions. After a comprehensive historical introduction, the work is divided into three sections dealing with writing inks, printing inks, and inks for miscellaneous purposes, respectively. Under Section 1 are considered the chemical nature and treatment of the various raw materials used for writing inks from lcmp black to galls, the composition of finished iron-gall, logwood, vanadium, aniline black, and coloured inks, as well as a comprehensive scheme €or the tech~ical examination of inks, handwriting specimens and the identification of forge:-ies.Section 2 deals with the manufacture and examination of printing inks. ,tnd Section 3 with the miscellaneous materials entering into the compositilxx of copying, marking, safety, sympathetic, typewriter inks and so on. Amongst new matter may be noted references to the use of lignone sulphni--,ites in connection with writing ink, a scheme for the identification of individual con- stituents in inks in the form of writing, and the application of filtered ultra-.& if )let light and of infra-red photography in the elucidation of those problems to which such methods are suited. The British Government Standard Specificatior:s for Writing Inks, revised in 1928, are included for the first time. The avaihble evidence upon the constitution of gallotannin is brought up to date and <tbly reviewed, and there is a Comprehensive list of British patents.It is as difficult to withhold admiration of the encyclopaedic scope cjf the matter and references in this book as it is of the erudition and industry displiiyed in its compilation. Practically nothing that comes to mind has escaped atterition, and it is with rather impish glee that the reviewer, after careful search, asserts that he finds no specific reference to the type of alkaline (ammoniacal) gallotannate- iron ink, said t o find favour in the United States, although the di-ammonium hydroxyferrigallate compound of Silbermann and Ozorovitz receives notice. Nor is there mention of that class of quick-drying writing fluids which depend for their efficiency upon partial destruction of the paper sizing by caustic alk 1.5 or sodium silicate.There is no evidence that lignone sulphonate inks have proved se-rious competitors to iron-gall writing inks (pp. 15 and 175). Apart from the unkttmwn quantity of permanence, the principal failing of this type lies in their liability to contain traces of free sulphurous acid to which suspicion attaches in connt-ction426 REVIEWS INKS : THEIR COMPOSITION AND MANUFACTURE. By C. AINSWORTH MITCHELL, D.Sc., F.I.C. Fourth Edition. Pp. xi + 408. London: Charles Grihn tt Co., Ltd. 1937. Price 12s. 6d. net. This, the fourth edition of the standard and, indeed, so far as the reviewer’s knowledge goes, the only text-book on the subject in the language, bridges L gap of 13 years. The author, pre-eminent in his particular sphere, needs little more introduction to the world of technical industry than he does in his official capicity to readers of THE ANALYST, while his reputation in forensic science in all that appertains to handwriting is international.The chemistry of ink, difficult as it is and at times not a little obscure, hcl- riot developed markedly in the interval since 1924; but what progress has been made is covered by Dr. Mitchell in this edition in a very thorough manner. He has found it necessary to enlarge his work to the extent of some 20 per cent. and, in addition, to rewrite a large portion. The arrangement of the book follows the lines of previous editions. After a comprehensive historical introduction, the work is divided into three sections dealing with writing inks, printing inks, and inks for miscellaneous purposes, respectively.Under Section 1 are considered the chemical nature and treatment of the various raw materials used for writing inks from lcmp black to galls, the composition of finished iron-gall, logwood, vanadium, aniline black, and coloured inks, as well as a comprehensive scheme €or the tech~ical examination of inks, handwriting specimens and the identification of forge:-ies. Section 2 deals with the manufacture and examination of printing inks. ,tnd Section 3 with the miscellaneous materials entering into the compositilxx of copying, marking, safety, sympathetic, typewriter inks and so on. Amongst new matter may be noted references to the use of lignone sulphni--,ites in connection with writing ink, a scheme for the identification of individual con- stituents in inks in the form of writing, and the application of filtered ultra-.& if )let light and of infra-red photography in the elucidation of those problems to which such methods are suited.The British Government Standard Specificatior:s for Writing Inks, revised in 1928, are included for the first time. The avaihble evidence upon the constitution of gallotannin is brought up to date and <tbly reviewed, and there is a Comprehensive list of British patents. It is as difficult to withhold admiration of the encyclopaedic scope cjf the matter and references in this book as it is of the erudition and industry displiiyed in its compilation.Practically nothing that comes to mind has escaped atterition, and it is with rather impish glee that the reviewer, after careful search, asserts that he finds no specific reference to the type of alkaline (ammoniacal) gallotannate- iron ink, said t o find favour in the United States, although the di-ammonium hydroxyferrigallate compound of Silbermann and Ozorovitz receives notice. Nor is there mention of that class of quick-drying writing fluids which depend for their efficiency upon partial destruction of the paper sizing by caustic alk 1.5 or sodium silicate. There is no evidence that lignone sulphonate inks have proved se-rious competitors to iron-gall writing inks (pp. 15 and 175). Apart from the unkttmwn quantity of permanence, the principal failing of this type lies in their liability to contain traces of free sulphurous acid to which suspicion attaches in connt-ction426 REVIEWS INKS : THEIR COMPOSITION AND MANUFACTURE.By C. AINSWORTH MITCHELL, D.Sc., F.I.C. Fourth Edition. Pp. xi + 408. London: Charles Grihn tt Co., Ltd. 1937. Price 12s. 6d. net. This, the fourth edition of the standard and, indeed, so far as the reviewer’s knowledge goes, the only text-book on the subject in the language, bridges L gap of 13 years. The author, pre-eminent in his particular sphere, needs little more introduction to the world of technical industry than he does in his official capicity to readers of THE ANALYST, while his reputation in forensic science in all that appertains to handwriting is international. The chemistry of ink, difficult as it is and at times not a little obscure, hcl- riot developed markedly in the interval since 1924; but what progress has been made is covered by Dr.Mitchell in this edition in a very thorough manner. He has found it necessary to enlarge his work to the extent of some 20 per cent. and, in addition, to rewrite a large portion. The arrangement of the book follows the lines of previous editions. After a comprehensive historical introduction, the work is divided into three sections dealing with writing inks, printing inks, and inks for miscellaneous purposes, respectively. Under Section 1 are considered the chemical nature and treatment of the various raw materials used for writing inks from lcmp black to galls, the composition of finished iron-gall, logwood, vanadium, aniline black, and coloured inks, as well as a comprehensive scheme €or the tech~ical examination of inks, handwriting specimens and the identification of forge:-ies.Section 2 deals with the manufacture and examination of printing inks. ,tnd Section 3 with the miscellaneous materials entering into the compositilxx of copying, marking, safety, sympathetic, typewriter inks and so on. Amongst new matter may be noted references to the use of lignone sulphni--,ites in connection with writing ink, a scheme for the identification of individual con- stituents in inks in the form of writing, and the application of filtered ultra-.& if )let light and of infra-red photography in the elucidation of those problems to which such methods are suited. The British Government Standard Specificatior:s for Writing Inks, revised in 1928, are included for the first time.The avaihble evidence upon the constitution of gallotannin is brought up to date and <tbly reviewed, and there is a Comprehensive list of British patents. It is as difficult to withhold admiration of the encyclopaedic scope cjf the matter and references in this book as it is of the erudition and industry displiiyed in its compilation. Practically nothing that comes to mind has escaped atterition, and it is with rather impish glee that the reviewer, after careful search, asserts that he finds no specific reference to the type of alkaline (ammoniacal) gallotannate- iron ink, said t o find favour in the United States, although the di-ammonium hydroxyferrigallate compound of Silbermann and Ozorovitz receives notice.Nor is there mention of that class of quick-drying writing fluids which depend for their efficiency upon partial destruction of the paper sizing by caustic alk 1.5 or sodium silicate. There is no evidence that lignone sulphonate inks have proved se-rious competitors to iron-gall writing inks (pp. 15 and 175). Apart from the unkttmwn quantity of permanence, the principal failing of this type lies in their liability to contain traces of free sulphurous acid to which suspicion attaches in connt-ction426 REVIEWS INKS : THEIR COMPOSITION AND MANUFACTURE. By C. AINSWORTH MITCHELL, D.Sc., F.I.C. Fourth Edition. Pp. xi + 408. London: Charles Grihn tt Co., Ltd. 1937. Price 12s. 6d. net. This, the fourth edition of the standard and, indeed, so far as the reviewer’s knowledge goes, the only text-book on the subject in the language, bridges L gap of 13 years.The author, pre-eminent in his particular sphere, needs little more introduction to the world of technical industry than he does in his official capicity to readers of THE ANALYST, while his reputation in forensic science in all that appertains to handwriting is international. The chemistry of ink, difficult as it is and at times not a little obscure, hcl- riot developed markedly in the interval since 1924; but what progress has been made is covered by Dr. Mitchell in this edition in a very thorough manner. He has found it necessary to enlarge his work to the extent of some 20 per cent. and, in addition, to rewrite a large portion.The arrangement of the book follows the lines of previous editions. After a comprehensive historical introduction, the work is divided into three sections dealing with writing inks, printing inks, and inks for miscellaneous purposes, respectively. Under Section 1 are considered the chemical nature and treatment of the various raw materials used for writing inks from lcmp black to galls, the composition of finished iron-gall, logwood, vanadium, aniline black, and coloured inks, as well as a comprehensive scheme €or the tech~ical examination of inks, handwriting specimens and the identification of forge:-ies. Section 2 deals with the manufacture and examination of printing inks. ,tnd Section 3 with the miscellaneous materials entering into the compositilxx of copying, marking, safety, sympathetic, typewriter inks and so on.Amongst new matter may be noted references to the use of lignone sulphni--,ites in connection with writing ink, a scheme for the identification of individual con- stituents in inks in the form of writing, and the application of filtered ultra-.& if )let light and of infra-red photography in the elucidation of those problems to which such methods are suited. The British Government Standard Specificatior:s for Writing Inks, revised in 1928, are included for the first time. The avaihble evidence upon the constitution of gallotannin is brought up to date and <tbly reviewed, and there is a Comprehensive list of British patents. It is as difficult to withhold admiration of the encyclopaedic scope cjf the matter and references in this book as it is of the erudition and industry displiiyed in its compilation.Practically nothing that comes to mind has escaped atterition, and it is with rather impish glee that the reviewer, after careful search, asserts that he finds no specific reference to the type of alkaline (ammoniacal) gallotannate- iron ink, said t o find favour in the United States, although the di-ammonium hydroxyferrigallate compound of Silbermann and Ozorovitz receives notice. Nor is there mention of that class of quick-drying writing fluids which depend for their efficiency upon partial destruction of the paper sizing by caustic alk 1.5 or sodium silicate. There is no evidence that lignone sulphonate inks have proved se-rious competitors to iron-gall writing inks (pp.15 and 175). Apart from the unkttmwn quantity of permanence, the principal failing of this type lies in their liability to contain traces of free sulphurous acid to which suspicion attaches in connt-ction426 REVIEWS INKS : THEIR COMPOSITION AND MANUFACTURE. By C. AINSWORTH MITCHELL, D.Sc., F.I.C. Fourth Edition. Pp. xi + 408. London: Charles Grihn tt Co., Ltd. 1937. Price 12s. 6d. net. This, the fourth edition of the standard and, indeed, so far as the reviewer’s knowledge goes, the only text-book on the subject in the language, bridges L gap of 13 years. The author, pre-eminent in his particular sphere, needs little more introduction to the world of technical industry than he does in his official capicity to readers of THE ANALYST, while his reputation in forensic science in all that appertains to handwriting is international.The chemistry of ink, difficult as it is and at times not a little obscure, hcl- riot developed markedly in the interval since 1924; but what progress has been made is covered by Dr. Mitchell in this edition in a very thorough manner. He has found it necessary to enlarge his work to the extent of some 20 per cent. and, in addition, to rewrite a large portion. The arrangement of the book follows the lines of previous editions. After a comprehensive historical introduction, the work is divided into three sections dealing with writing inks, printing inks, and inks for miscellaneous purposes, respectively. Under Section 1 are considered the chemical nature and treatment of the various raw materials used for writing inks from lcmp black to galls, the composition of finished iron-gall, logwood, vanadium, aniline black, and coloured inks, as well as a comprehensive scheme €or the tech~ical examination of inks, handwriting specimens and the identification of forge:-ies.Section 2 deals with the manufacture and examination of printing inks. ,tnd Section 3 with the miscellaneous materials entering into the compositilxx of copying, marking, safety, sympathetic, typewriter inks and so on. Amongst new matter may be noted references to the use of lignone sulphni--,ites in connection with writing ink, a scheme for the identification of individual con- stituents in inks in the form of writing, and the application of filtered ultra-.& if )let light and of infra-red photography in the elucidation of those problems to which such methods are suited.The British Government Standard Specificatior:s for Writing Inks, revised in 1928, are included for the first time. The avaihble evidence upon the constitution of gallotannin is brought up to date and <tbly reviewed, and there is a Comprehensive list of British patents. It is as difficult to withhold admiration of the encyclopaedic scope cjf the matter and references in this book as it is of the erudition and industry displiiyed in its compilation. Practically nothing that comes to mind has escaped atterition, and it is with rather impish glee that the reviewer, after careful search, asserts that he finds no specific reference to the type of alkaline (ammoniacal) gallotannate- iron ink, said t o find favour in the United States, although the di-ammonium hydroxyferrigallate compound of Silbermann and Ozorovitz receives notice.Nor is there mention of that class of quick-drying writing fluids which depend for their efficiency upon partial destruction of the paper sizing by caustic alk 1.5 or sodium silicate. There is no evidence that lignone sulphonate inks have proved se-rious competitors to iron-gall writing inks (pp. 15 and 175). Apart from the unkttmwn quantity of permanence, the principal failing of this type lies in their liability to contain traces of free sulphurous acid to which suspicion attaches in connt-ction426 REVIEWS INKS : THEIR COMPOSITION AND MANUFACTURE. By C. AINSWORTH MITCHELL, D.Sc., F.I.C.Fourth Edition. Pp. xi + 408. London: Charles Grihn tt Co., Ltd. 1937. Price 12s. 6d. net. This, the fourth edition of the standard and, indeed, so far as the reviewer’s knowledge goes, the only text-book on the subject in the language, bridges L gap of 13 years. The author, pre-eminent in his particular sphere, needs little more introduction to the world of technical industry than he does in his official capicity to readers of THE ANALYST, while his reputation in forensic science in all that appertains to handwriting is international. The chemistry of ink, difficult as it is and at times not a little obscure, hcl- riot developed markedly in the interval since 1924; but what progress has been made is covered by Dr. Mitchell in this edition in a very thorough manner.He has found it necessary to enlarge his work to the extent of some 20 per cent. and, in addition, to rewrite a large portion. The arrangement of the book follows the lines of previous editions. After a comprehensive historical introduction, the work is divided into three sections dealing with writing inks, printing inks, and inks for miscellaneous purposes, respectively. Under Section 1 are considered the chemical nature and treatment of the various raw materials used for writing inks from lcmp black to galls, the composition of finished iron-gall, logwood, vanadium, aniline black, and coloured inks, as well as a comprehensive scheme €or the tech~ical examination of inks, handwriting specimens and the identification of forge:-ies.Section 2 deals with the manufacture and examination of printing inks. ,tnd Section 3 with the miscellaneous materials entering into the compositilxx of copying, marking, safety, sympathetic, typewriter inks and so on. Amongst new matter may be noted references to the use of lignone sulphni--,ites in connection with writing ink, a scheme for the identification of individual con- stituents in inks in the form of writing, and the application of filtered ultra-.& if )let light and of infra-red photography in the elucidation of those problems to which such methods are suited. The British Government Standard Specificatior:s for Writing Inks, revised in 1928, are included for the first time. The avaihble evidence upon the constitution of gallotannin is brought up to date and <tbly reviewed, and there is a Comprehensive list of British patents.It is as difficult to withhold admiration of the encyclopaedic scope cjf the matter and references in this book as it is of the erudition and industry displiiyed in its compilation. Practically nothing that comes to mind has escaped atterition, and it is with rather impish glee that the reviewer, after careful search, asserts that he finds no specific reference to the type of alkaline (ammoniacal) gallotannate- iron ink, said t o find favour in the United States, although the di-ammonium hydroxyferrigallate compound of Silbermann and Ozorovitz receives notice. Nor is there mention of that class of quick-drying writing fluids which depend for their efficiency upon partial destruction of the paper sizing by caustic alk 1.5 or sodium silicate.There is no evidence that lignone sulphonate inks have proved se-rious competitors to iron-gall writing inks (pp. 15 and 175). Apart from the unkttmwn quantity of permanence, the principal failing of this type lies in their liability to contain traces of free sulphurous acid to which suspicion attaches in connt-ction JANUARY, 1947 Vol. 72, No. 850 The Estimation of 2:2Bis-(p-chlorophenyl)=l: 1: 1- trichloroethane (p,p’=DDT) by Methods depending on its Dehydrohalogenation BY R. L. WAIN AND A. E. MARTIN IT was first demonstrated by Zeidlerl that 2 : 2-bis-(~-chlorophenyl)-l: 1 : 1-trichloroethane (@,p’-DDT), when heated under reflux with alcoholic potassium hydroxide, loses one molecule of hydrogen chloride to form 2 : 2-bis-(~-chlorophenyl)-l: 1-dichloroethylene (DDX), thus, Cl*-(>.l + KOH -+ C1 o - c - o c l + KC1 + -0 CCl, ECla and since the use of DDT as an insecticide this reaction has been utilised by a number of workers for its estimation.Providing that the dehydrohalogenation occurs quantitatively as in the equation above and that the alkali has no further action on the DDX produced, the DDT can be estimated indirectly either by acidimetric titration of the alkali consumed or by determination of the chloride ion formed. The former method, although rapid, is more susceptible to analytical error and has not been greatly employed. The latter procedure has been used by Gunther2 and otliers.3s4s6s6s7 Both methods were examined in 1943 by one of the present writers, using pure p,$’DDT. With both, high results were frequently obtained, indicating either that hydrolysis of the substance had proceeded too far or that one or more atoms of chlorine were being displaced from DDX by the action of the alcoholic alkali. To test this latter possibility, DDX was heated under reflux for varying times with N alcoholic potassium hydroxide.Under these conditions, the substance was apparently stable. When 25 per cent. alcoholic potash solution was used, however, the mixture gave a strongly positive reaction for chloride after four 12 WAIN AND MARTIN : THE ESTIMATION OF 2: 2-BIS-(p-CHLOROPHENYL)- hours, and after sixteen hours bis-(P-chloropheny1)-acetic acid was readily isolated from the mixture. This acid, since described by Grummitt et aZ.,8 was also prepared in quantity by heating either p,p'-DDT or DDX with alcoholic sodium ethoxide in a sealed tube (cf.Fritsch and Feldmang). Finally it was isolated from the products obtained by heating p,p'-DDT with N alcoholic potassium hydroxide for 30 minutes under reflux. These experiments show that, when heated under reflux with alcoholic alkali, p,p'-DDT can yield more than one molecule of hydrogen chloride per molecule, and they thus afford an explanation of the high analytical results already noted. Commercial samples of DDT contain about fourteen substances,lo the chief of which are fi,p'-DDT (63 to 77 per cent .), l-trichloro-2-o-chlorophenyl-Z-p-chlorophenylethane (o,p'DDT) (8 to 21 per cent.), 1 :l-dichloro-2:2-bis-(+-chlorophenyl)-ethane (DDD) (0-3 to 4.0 per cent.), 2-trichloro-l-o-chlorophenylethyl-~-chlorobenzenesulphonate (0.4 to 1 -85 per cent.) and j5-chlorophenyl-trichloromethyl-carbinol (about 0.2 per cent.).Methods of estimation depending on dehydrochlorination applied to such a mixture would therefore not be expected to be reliable, quite apart from the considerations outlined above. For this reason the present work was restricted to an investigation of the behaviour of pure $,p'-DDT and DDX with alcoholic alkali under various conditions. The first method adopted involved the estimation of chloride ion by Volhard titration, by a procedure similar to that adopted by Gunther.2 In addition, an acidimetric method was employed in which the loss of alkalinity in the ethanolic potassium hydroxide solution was determined directly by titration.Materials- p,fi'-DDT-The commercial material, crystallised three times from alcohol. Colourless needles, m.p. 109" to 1096" C. DDX-Prepared from pure $,p'-DDT by the action of alcoholic potassium hydroxide. Crystallised three times from alcohol. R1.p. 87" to 88" C. Standard alcoholic potassium hydroxide solution-The pure solid was heated under reflux with redistilled absolute alcohol and the solution was cooled, filtered and standardised. EXPERIMENTAL ACTION OF BOILING ALCOHOLIC POTASSIUM HYDROXIDE SOLUTION ON p,p'-DDT- (a) Modijed Gunther procedure for the estimation of p,P'-DDT-Weighed quantities of fi,P'-DDT were introduced into a 250-ml. round-bottomed flask of the Quickfit type and 60 ml.of N alcoholic potassium hydroxide were added. A reflux condenser was fitted, and the mixture was heated over a naked flame. After boiling for 30 minutes, 25 ml. of water, 60 ml. of 2 N nitric acid and a further 25 ml. of water were added successively through the vertical condenser. The condenser was then detached and 3 ml. of redistilled nitrobenzene were added to the mixture and followed by 25 ml. of 0.1 N silver nitrate: After stoppering and shaking the flask to coagulate the silver chloride and coat the particles with a layer of nitrobenzene, the stopper was removed and rinsed into the flask with water. Three ml. of N ferric nitrate were added and the excess of silver was titrated with 0.05 N potassium thiocyanate. Blank estimations without DDT led to a small correction which was allowed for in all results.These results, calculated on the assumption that one molecule of DDT yields one molecule of hydrogen chloride under these conditions, are assembled in Table I. (b) Procedure with acidimetric titratiort e.nding-Weighed quantities of P,p'-DDT were heated under reflux with 50 ml. of N alcoholic potassium hydroxide for 30 minutes as described above. The condenser and joint were then rinsed into the flask with water, 50 ml. of standard nitric acid were added and the mixture was titrated with 0-1 N sodium hydroxide, using phenolphthalein as indicator. The standard acid used was slightly stronger than the alcoholic alkali; this ensured a small titration of alkali for the blank determination, which was allowed for in each estimation.The results, calculated as before, are given in Table I. TABLE I ESTIMATION OF $,$'-DDT Wt. of DDT taken, mg. . . 119.5 159-0 161.0 344.0 377.0 617.8 640.0 Recovery, per cent. . . 104.2 103.8 105.3 105.3 105.9 102.1 101.0 Ending with acidimetric titration Wt. of DDTtaken, mg. . . 118.9 201.9 239.8 312.4 470.5 617.2 805.0 1594.2 Recovery, per cent. . . 106.2 99-1 104.3 104-6 102.3 108.6 105.8 103.6 Ending with Volhard titration1 : 1 : 1-TRICHLOROETHANE (p,p'-DDT)* 3 (c) Efect of duration of boiling on dehydrohalogenation of p,p'-DDT-Weighed quantities of p,p'-D>nT were refluxed with 50 ml. of N alcoholic potassium hydroxide for measured times and the chloride ion present in the system was estimated as in (a). The results are given in Table 11.TABLE I1 EFFECT OF DURATION OF BOILING ON DEHYDROHALOGENATION OF p,p'-DDT Boiling Wt. of Boiling Wt. of period DDT taken Recovery period DDT taken Recovery 0.25 501.2 102.6 4.0 503.5 102.8 500.1 102-4 498.2 105-2 615 499.0 102.5 i : 0 499.4 105.5 500.6 104.4 12.0 502.1 107.5 i:0 503.3 106.1 16.0 511.1 107-7 499.5 104.1 24-0 500.0 107.9 hours mg. Yo hours mg. % iI0 497.3 103.2 48.0 499.4 111.1 3 ) 600.7 105.1 DEHYDROHALOGENATION OF p,p'-DDT BY ALCOHOLIC ALKALI AT LOWER TEMPERATURES- Twenty-five ml. lots of a solution of p,p'-DDT in alcohol were pipetted into 300-ml. flasks and 25-ml. quantities of standard (2 N or 0.2 N ) alcoholic potassium hydroxide solution were added. The flasks were stoppered and allowed to stand at the temperature of the laboratory (18" to 18.5" C.) or in an incubator at 23" C .for measured times, after which the reaction was stopped by addition of excess of standard nitric acid. Chloride ion was then estimated in the mixtures by the procedure outlined above (p. 2). All results are given in Table 111. TABLE 111 DEHYDROHALOGENATION OF p,p'-DDT AT LOWER TEMPERATURES 497-9 mg. of p,p'-DDT in 50 ml.of 0.996 N alcoholic KOH at 18Oto 18.5" C. 495-0 mg. of p,p'-DDT in 50 ml. of 0.0986 N alcoholic KOH at 23" C. Time DDT recovered Time DDT recovered A \ I A \ mins. % mins. % 6 99.7 - - 10 99.7 10 83.8 15 99.7 - - 20 99.8 20 97.0 30 99.9 30 99-7 45 100-0 40 99.5 60 99.8 60 100.0 90 100*0 - - 120 99.8 120 100.1 150 99.9 - - 180 99.8 180 100.1 ACTION OF BOILING POTASSIUM HYDROXIDE SOLUTION ON DDX- (i) Efect of time on the decomposition of DDX by boiling alcoholic alkali-A series of experiments as in (c) above were carried out with DDX, the percentage decomposition being calculated on the assumption that both non-nuclear chlorine atoms become displaced as chloride ion.TABLE IV EFFECT OF DURATION OF BOILING AND PRESENCE OF POTASSIUM CHLORIDE ON Results are given in Table IV. THE DECOMPOSITION OF DDX Duration of boiling, hrs. . . 0.5 4.0 8.0 24.0 48.0 Decomposition of DDX, yo: In absence of KCl . . 0.12 to <0*08 0.12 0-4 1 3.51 15-09 In presence of KCl . . <0.08 0.6 to <0*08 0.35 1.71 5:67 The weight of DDX taken for each experiment was approximately 500 mg. (496.1 to 506.7) (ii) Injuence of potassium chloride on the rate of decomposition of DDX by boiling alcohotic alkali-A further series of experiments carried out as in (i) above but in presence of an approximately equimolecular quantity of potassium chloride gave the results shown in Table IV.4 FORMATION OF BIS-(p-CHLOROPHENYL)-ACETIC ACID FROM p,p'-DDT AND FROM DDX- (a) Eight g.of DDX were heated at 120" C. for 24 hours in a sealed Carius tube with alcoholic sodium ethoxide, prepared by dissolving 1.8 g. of sodium in 30 ml. of absolute alcohol. To the product 300 ml. of water were added, and the alcohol was then distilled off and the mixture extracted with ether. The extract, after removal of ether, gave 4.72 g. of solid having m.p. 72" to 79" C. After crystallisation from alcohol it melted at 83" to 87" C. This substance did not depress the melting-point of pure DDX and was therefore the unchanged starting material.The aqueous layer was freed from ether and filtered. On acidification the filtrate yielded 3.05 g. of a white crystalline solid havihg m.p. 164" to 166" C. This was crystallised twice from chloroform and obtained as colourless prisms, m.p. 166" C., which were shown by analysis to be bis-(p-chloropheny1)-acetic acid. Yield: 33.8 per cent. (Found: C, 5943%; H, 3.3%; equiv., 281.0. Calc. for Cl,HlOO,C1,: C, 5943%; H, 3.6%; equiv., 281.0.) Grummitt et aZ.* give m.p. 163 to 164" C. WAIN AND MARTIN : THE ESTIMATION OF 2: %BIS-(~-CHLOROPHENYL)- The following derivatives were prepared- Ethyl bis-(P-chlorophenyl acetate) (C1C6H4) ,CHCOOC,H,.* Colourless prisms from alcohol, m.p. 89" C. Bis-(p-clzZorophenyZ)-acetamide (ClC,H,) ,CHCONH,.Colourless needles from methyl alcohol, m.p. 157" C. (Found: N, 4.9%; Cl4HllONC1, requires N, 5*oy0.) Bis-(p-chloropheny1)-acetanilide (ClC,H,) ,CHCONHC,H,.* Slender colourless needles from methyl alcohol, m.p. 208" to 209" C. (Found: N, 4.1%. C,,H,,ONCl, requires N 3.9%.) (b) A similar experiment using 10 g. of p,p'-DDT, 2.6 g. of sodium and 45 ml. of alcohol, heated in a sealed tube at 120" C. for 24 hours, yielded 3-35 g. of bis-(9-chloropheny1)-acetic acid of m.p. 164" to 165" C (42.2% of theoretical) and 4.7 g. of unchanged DDX. (c) A solution of 4 g. of DDX in 100 ml. of absolute alcohol containing 25 g. of potassium hydroxide was heated under reflux. The solution gradually became cloudy and, after 4 hours a small portion gave a strongly positive reaction for chloride.After 16 hours the mixture was diluted with water, alcohol was distilled off and the aqueous solution extracted with ether. The extract yielded unchanged DDX, having m.p. 83" to 86" C. after one crystallisation from methyl alcohol. The white solid that separated was crystallised successively from methyl alcohol and twice from chloro- form, yielding colourless prisms, m.p. 166" C., which did not depress the melting-point of the analysed specimen of bis-(p-chloropheny1)-acetic acid. (d) An experiment carried out exactly as in ( c ) , but on 4 g. of $,$'-DDT, gave 0.32 g. of the same acid. (e) Five g. of p,$'-DDT boiled under reflux with N alcoholic potassium hydroxide gave a small yield (about 15 me;.) of bis-(p-chloropheny1)-acetic acid, the identity of which was proved by melting and mixed melting points.DISCUSSION Methods of analysis of p,p'-DDT based on the determination of chloride or consumed alkali after boiling under reflux with N alcoholic potassium hydroxide gave results significantly higher than the theoretical value (Tables I and 11). Gunther,2 however, who used similar conditions and method of estimating chloride ion, obtained not more than 101.0 per cent. recovery in his experiments with pure p,p'-DDT, and in two of his seven recorded estimations less than 100 per cent. recovery was obtained. Nevertheless, the treatment he recommended, viz., boiling under reflux with N alcoholic potassium hydroxide for 30 minutes, would appear to be unnecessarily drastic, for, as Brand and Busse-Sundermannu have shown, 5g.of P,$'-DDT become dehydrohalogenated completely within three minutes on heating with M) ml. of 0-5 N alcoholic alkali under reflux (see also Table 11). That $,p'-DDT becomes partially converted to bis-(9-chloropheny1)-acetic acid by boiling with alcoholic potash, has been demonstrated. If it is assumed that DDX is not an inter- mediate product, this reaction may be represented as follows: (Found: C, 6203%; H, 4.7%; C,,H,,O,Cl, requires C, 62.2y0; H, 4.6y0.) The aqueous solution was freed from ether, filtered and acidified. C I c t $ e + 30H'-+ C1 * H e + 3C1' + H,O CCI, COOH * Since this work was completed the ethyl ester and anilide have been described by G%tzi and Stammbach (Helu. Chim. Ada, 1946, 29, 663) who give melting-points 89' to 90" C.and 213O to 214" C. respectively.1 : 1 : 1 -TRICHLOROETHANE (p,@'-DDT) 5 and it will be noted that three atoms of chlorine per molecule of DDT are liberated as chloride ion. Thus, although this substance is dehydrochlorinated only 1/67th as fast as the on boiling with alcoholic alkali for 30 minutes, Cristol and Hallerl2 showed that the former com- pound undergoes a decomposition in which 4 per cent. of (0-chloropheny1)-(p-chloropheny1)- acetic acid is produced. The same workers, however, demonstrated that this amount is not further increased by longer heating and also that the ethylene derivative, 2-(o-chlorophenyl)- (9-chloropheny1)-1 : 1-dichloroethylene, is stable to boiling alcoholic alkali. For these reasons it was concluded that the ethylene derivative is not an intermediate product in the formation of the substituted acetic acid from o,p'-DDT.Thus, whenp,p'-DDT was boiled under reflux with N alcoholic potassium hydroxide for 30 minutes, approximately 1.04 equivalents of chloride ion per mole of DDT were liberated, an amount which increased only slightly on continuing the boiling for longer periods up to 24 hours (Tables I and 11). Further, DDX was found to be almost completely stable to boiling N alcoholic alkali for periods up to 4 hours (Table IV). These results suggest that when p,p'-DDT is boiled with alcoholic alkali, two reactions are possible, one involving simple dehydrohalogenation to DDX and the other a direct hydrolysis of the -CCl, group to -COOH. In this latter reaction it is immaterial whether two or three chlorine atoms are hydrolysed simultaneously. If three are removed, the acid is produced directly as in the equation above. A bimolecular attack on this group, however, would displace two chlorine atoms to form the acid chloride, which would then yield the acid by secondary hydrolysis. That DDX yields negligible chloride ion on boiling with N alcoholic alkali supports the view that this substance is not an intermediate product in the formation of bis-(p-chloro- pheny1)-acetic acid from p,p'-DDT.There remains, however, the possibility that chloride displaced from $,p'-DDT in dehydrohalogenation might influence the stability of the pro- duced DDX to boiling alcoholic alkali. To test this possibility a series of experiments with DDX were made in which potassium chloride was added equivalent in amount to that which would be present if the substance had been formed in situ from p,p'-DDT.Again, the alcoholic alkali had little action (Table IV). This stability of DDX is not surprising in view of the known resistance to hydrolysis of compounds containing chlorine attached to an unsaturated carbon atom. When more drastic conditions were employed, however, such as boiling DDX with 25 per cent. alcoholic potash for 16 hours under reflux or heating with sodium ethoxide in a sealed tube a$ 120" C., bis-(p-chloropheny1)-acetic acid was produced. C l o - i - c ) . l + 20H' --+ [3p]---+ C l e r e c1 /"\ c1 d'0H 0 OH The dehydrohalogenation experiments carried out at lower temperatures (Table IIT), showed the conversion of p,p'-DDT to DDX to proceed rapidly and quantitatively, and even after three hours the alkali was apparently without further action." It will be noted that with a concentration of alkali of only 0.1 N the reaction was almost complete within 30 minutes (Table 111).It would therefore appear that, although boiling under reflux with alcoholic alkali enables a reaction, undesirable from the analytical point of view, to take place, the action of this reagent on p,p'-DDT at laboratory temperatures is mainly one of simple dehydrohalogenation. It is of interest here to note that Cristol and HalleF found that o,p'-DDT treated with etha- nolic sodium hydroxide a t room temperatures for periods up to four days yields only one molecule of hydrogen chloride per molecule.The present results clearly indicate that with p,p'-DDT, treatment with 0.1 N alcoholic alkali for 30-60 minutes provides more suitable conditions for quantitative dehydrochlorina- tion than those described by Gunther.2 Experiments are being continued and further results will be communicated in a later paper. A similar decomposition has recently been shown to occur with o,p'-DDT. In the present work similar results were noted. / \ + 2C1' * That traces of bis(p-chloropheny1)-acetic acid can be produced under these conditions has been The amount produced, however, apparently has an insignificant indicated by experiments now in progress. effect in the estimation.6 MILTON AND HOSKINS: THE ESTIMATION OF TRACES OF MERCURY IN URINE SUMMARY When boiled under reflux with N alcoholic alkali, p,p'-DDT has been shown to lose slightly more than one gram-ion of chloride per mole, indicating that the reaction is not one of simple dehydrohalogenation. This was confirmed by the isolation of bis-(9-chlorophenyl) acetic acid as well as DDX from the products of the reaction. This acid could only be produced from DDX by drastic treatment such as prolonged boiling with concentrated alcoholic potash or heating with alcoholic sodium ethoxide in a sealed tube; boiling under reflux with N alcoholic alkali for periods up to 4 hours had apparently no effect. These results indicate that by boiling p,p'-DDT with N alcoholic alkali the acid can be formed directly by a hydrolysis of -CCl, to -COOH with consequent liberation of three chloride ions per molecule, and that DDX is not an intermediate product of the reaction. The presence of potassium chloride was found not to affect the stability of DDX to boiling N-alcoholic alkali. The action of N and 0.1 N alcoholic alkali on p,p'-DDT at lower temperatures appeared to be one of simple dehydrohalogenation, and it is suggested that such milder treatment will enable more accurate estimation of this isomer than the procedure recommended by other workers. Three derivatives of bis-(p-chloropheny1)-acetic acid are described. 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. WYE REFERENCES Zeidler, O., B e y . , 1874, 7, 1180. Gunther, F. A., Ind. Eng. Chem., Anal. Ed., 1945, 17, 149. Neal, P. A., and co-workers, U.S. Pub. Health Serv., Pub. Health Depts. supp., 1944, No. 177. Powning, R. F., J. Coun. Sci. Ind. Res. Aust.. 1945, 18, 121. Fleck, E. E., J. Assoc. 08. Agr. Chem., 1945, 28, 585. Cristol, S. J., J. Amer. Chem. Soc., 1945, 67, 1404. Wichmann, H. J., and co-workers, J. Assoc. 08. Agr. Chent., 1946, 29, 188. Grummitt, O., Buck, A., and Stearns, J., J. Amer. Chem. SOC., 1945, 67, 156. Fritsch, P., and Feldman, F., Annalen, 1899, 306, 81. Haller, H. L., and co-workers, J. Amer. Chem. SOL, 1945, 67, 1591. Brand, K., and Busse-Sundermann, A., Bet'., 1942, 75B, 1819. Cristol, S. J . , and Haller, H. L., J. Awer. Chem. SOC., 1945. 47, 2222. COLLEGE (UNIVERSITY OF LONDON) KENT November, 1946

ISSN:0003-2654    

DOI:10.1039/AN947720001b

出版商:RSC    

年代:1947

数据来源: RSC

ISSN:0003-2654    

DOI:10.1039/AN94772BX003

出版商:RSC    

年代:1947

数据来源: RSC

摘要:

426 REVIEWS INKS : THEIR COMPOSITION AND MANUFACTURE. By C. AINSWORTH MITCHELL, D.Sc., F.I.C. Fourth Edition. Pp. xi + 408. London: Charles Grihn tt Co., Ltd. 1937. Price 12s. 6d. net. This, the fourth edition of the standard and, indeed, so far as the reviewer’s knowledge goes, the only text-book on the subject in the language, bridges L gap of 13 years. The author, pre-eminent in his particular sphere, needs little more introduction to the world of technical industry than he does in his official capicity to readers of THE ANALYST, while his reputation in forensic science in all that appertains to handwriting is international. The chemistry of ink, difficult as it is and at times not a little obscure, hcl- riot developed markedly in the interval since 1924; but what progress has been made is covered by Dr.Mitchell in this edition in a very thorough manner. He has found it necessary to enlarge his work to the extent of some 20 per cent. and, in addition, to rewrite a large portion. The arrangement of the book follows the lines of previous editions. After a comprehensive historical introduction, the work is divided into three sections dealing with writing inks, printing inks, and inks for miscellaneous purposes, respectively. Under Section 1 are considered the chemical nature and treatment of the various raw materials used for writing inks from lcmp black to galls, the composition of finished iron-gall, logwood, vanadium, aniline black, and coloured inks, as well as a comprehensive scheme €or the tech~ical examination of inks, handwriting specimens and the identification of forge:-ies.Section 2 deals with the manufacture and examination of printing inks. ,tnd Section 3 with the miscellaneous materials entering into the compositilxx of copying, marking, safety, sympathetic, typewriter inks and so on. Amongst new matter may be noted references to the use of lignone sulphni--,ites in connection with writing ink, a scheme for the identification of individual con- stituents in inks in the form of writing, and the application of filtered ultra-.& if )let light and of infra-red photography in the elucidation of those problems to which such methods are suited. The British Government Standard Specificatior:s for Writing Inks, revised in 1928, are included for the first time. The avaihble evidence upon the constitution of gallotannin is brought up to date and <tbly reviewed, and there is a Comprehensive list of British patents.It is as difficult to withhold admiration of the encyclopaedic scope cjf the matter and references in this book as it is of the erudition and industry displiiyed in its compilation. Practically nothing that comes to mind has escaped atterition, and it is with rather impish glee that the reviewer, after careful search, asserts that he finds no specific reference to the type of alkaline (ammoniacal) gallotannate- iron ink, said t o find favour in the United States, although the di-ammonium hydroxyferrigallate compound of Silbermann and Ozorovitz receives notice. Nor is there mention of that class of quick-drying writing fluids which depend for their efficiency upon partial destruction of the paper sizing by caustic alk 1.5 or sodium silicate.There is no evidence that lignone sulphonate inks have proved se-rious competitors to iron-gall writing inks (pp. 15 and 175). Apart from the unkttmwn quantity of permanence, the principal failing of this type lies in their liability to contain traces of free sulphurous acid to which suspicion attaches in connt-ction426 REVIEWS INKS : THEIR COMPOSITION AND MANUFACTURE. By C. AINSWORTH MITCHELL, D.Sc., F.I.C. Fourth Edition. Pp. xi + 408. London: Charles Grihn tt Co., Ltd. 1937. Price 12s. 6d. net. This, the fourth edition of the standard and, indeed, so far as the reviewer’s knowledge goes, the only text-book on the subject in the language, bridges L gap of 13 years. The author, pre-eminent in his particular sphere, needs little more introduction to the world of technical industry than he does in his official capicity to readers of THE ANALYST, while his reputation in forensic science in all that appertains to handwriting is international.The chemistry of ink, difficult as it is and at times not a little obscure, hcl- riot developed markedly in the interval since 1924; but what progress has been made is covered by Dr. Mitchell in this edition in a very thorough manner. He has found it necessary to enlarge his work to the extent of some 20 per cent. and, in addition, to rewrite a large portion. The arrangement of the book follows the lines of previous editions. After a comprehensive historical introduction, the work is divided into three sections dealing with writing inks, printing inks, and inks for miscellaneous purposes, respectively.Under Section 1 are considered the chemical nature and treatment of the various raw materials used for writing inks from lcmp black to galls, the composition of finished iron-gall, logwood, vanadium, aniline black, and coloured inks, as well as a comprehensive scheme €or the tech~ical examination of inks, handwriting specimens and the identification of forge:-ies. Section 2 deals with the manufacture and examination of printing inks. ,tnd Section 3 with the miscellaneous materials entering into the compositilxx of copying, marking, safety, sympathetic, typewriter inks and so on. Amongst new matter may be noted references to the use of lignone sulphni--,ites in connection with writing ink, a scheme for the identification of individual con- stituents in inks in the form of writing, and the application of filtered ultra-.& if )let light and of infra-red photography in the elucidation of those problems to which such methods are suited.The British Government Standard Specificatior:s for Writing Inks, revised in 1928, are included for the first time. The avaihble evidence upon the constitution of gallotannin is brought up to date and <tbly reviewed, and there is a Comprehensive list of British patents. It is as difficult to withhold admiration of the encyclopaedic scope cjf the matter and references in this book as it is of the erudition and industry displiiyed in its compilation.Practically nothing that comes to mind has escaped atterition, and it is with rather impish glee that the reviewer, after careful search, asserts that he finds no specific reference to the type of alkaline (ammoniacal) gallotannate- iron ink, said t o find favour in the United States, although the di-ammonium hydroxyferrigallate compound of Silbermann and Ozorovitz receives notice. Nor is there mention of that class of quick-drying writing fluids which depend for their efficiency upon partial destruction of the paper sizing by caustic alk 1.5 or sodium silicate. There is no evidence that lignone sulphonate inks have proved se-rious competitors to iron-gall writing inks (pp. 15 and 175). Apart from the unkttmwn quantity of permanence, the principal failing of this type lies in their liability to contain traces of free sulphurous acid to which suspicion attaches in connt-ction426 REVIEWS INKS : THEIR COMPOSITION AND MANUFACTURE.By C. AINSWORTH MITCHELL, D.Sc., F.I.C. Fourth Edition. Pp. xi + 408. London: Charles Grihn tt Co., Ltd. 1937. Price 12s. 6d. net. This, the fourth edition of the standard and, indeed, so far as the reviewer’s knowledge goes, the only text-book on the subject in the language, bridges L gap of 13 years. The author, pre-eminent in his particular sphere, needs little more introduction to the world of technical industry than he does in his official capicity to readers of THE ANALYST, while his reputation in forensic science in all that appertains to handwriting is international. The chemistry of ink, difficult as it is and at times not a little obscure, hcl- riot developed markedly in the interval since 1924; but what progress has been made is covered by Dr.Mitchell in this edition in a very thorough manner. He has found it necessary to enlarge his work to the extent of some 20 per cent. and, in addition, to rewrite a large portion. The arrangement of the book follows the lines of previous editions. After a comprehensive historical introduction, the work is divided into three sections dealing with writing inks, printing inks, and inks for miscellaneous purposes, respectively. Under Section 1 are considered the chemical nature and treatment of the various raw materials used for writing inks from lcmp black to galls, the composition of finished iron-gall, logwood, vanadium, aniline black, and coloured inks, as well as a comprehensive scheme €or the tech~ical examination of inks, handwriting specimens and the identification of forge:-ies.Section 2 deals with the manufacture and examination of printing inks. ,tnd Section 3 with the miscellaneous materials entering into the compositilxx of copying, marking, safety, sympathetic, typewriter inks and so on. Amongst new matter may be noted references to the use of lignone sulphni--,ites in connection with writing ink, a scheme for the identification of individual con- stituents in inks in the form of writing, and the application of filtered ultra-.& if )let light and of infra-red photography in the elucidation of those problems to which such methods are suited. The British Government Standard Specificatior:s for Writing Inks, revised in 1928, are included for the first time.The avaihble evidence upon the constitution of gallotannin is brought up to date and <tbly reviewed, and there is a Comprehensive list of British patents. It is as difficult to withhold admiration of the encyclopaedic scope cjf the matter and references in this book as it is of the erudition and industry displiiyed in its compilation. Practically nothing that comes to mind has escaped atterition, and it is with rather impish glee that the reviewer, after careful search, asserts that he finds no specific reference to the type of alkaline (ammoniacal) gallotannate- iron ink, said t o find favour in the United States, although the di-ammonium hydroxyferrigallate compound of Silbermann and Ozorovitz receives notice.Nor is there mention of that class of quick-drying writing fluids which depend for their efficiency upon partial destruction of the paper sizing by caustic alk 1.5 or sodium silicate. There is no evidence that lignone sulphonate inks have proved se-rious competitors to iron-gall writing inks (pp. 15 and 175). Apart from the unkttmwn quantity of permanence, the principal failing of this type lies in their liability to contain traces of free sulphurous acid to which suspicion attaches in connt-ction426 REVIEWS INKS : THEIR COMPOSITION AND MANUFACTURE. By C. AINSWORTH MITCHELL, D.Sc., F.I.C. Fourth Edition. Pp. xi + 408. London: Charles Grihn tt Co., Ltd. 1937. Price 12s. 6d. net. This, the fourth edition of the standard and, indeed, so far as the reviewer’s knowledge goes, the only text-book on the subject in the language, bridges L gap of 13 years.The author, pre-eminent in his particular sphere, needs little more introduction to the world of technical industry than he does in his official capicity to readers of THE ANALYST, while his reputation in forensic science in all that appertains to handwriting is international. The chemistry of ink, difficult as it is and at times not a little obscure, hcl- riot developed markedly in the interval since 1924; but what progress has been made is covered by Dr. Mitchell in this edition in a very thorough manner. He has found it necessary to enlarge his work to the extent of some 20 per cent. and, in addition, to rewrite a large portion.The arrangement of the book follows the lines of previous editions. After a comprehensive historical introduction, the work is divided into three sections dealing with writing inks, printing inks, and inks for miscellaneous purposes, respectively. Under Section 1 are considered the chemical nature and treatment of the various raw materials used for writing inks from lcmp black to galls, the composition of finished iron-gall, logwood, vanadium, aniline black, and coloured inks, as well as a comprehensive scheme €or the tech~ical examination of inks, handwriting specimens and the identification of forge:-ies. Section 2 deals with the manufacture and examination of printing inks. ,tnd Section 3 with the miscellaneous materials entering into the compositilxx of copying, marking, safety, sympathetic, typewriter inks and so on.Amongst new matter may be noted references to the use of lignone sulphni--,ites in connection with writing ink, a scheme for the identification of individual con- stituents in inks in the form of writing, and the application of filtered ultra-.& if )let light and of infra-red photography in the elucidation of those problems to which such methods are suited. The British Government Standard Specificatior:s for Writing Inks, revised in 1928, are included for the first time. The avaihble evidence upon the constitution of gallotannin is brought up to date and <tbly reviewed, and there is a Comprehensive list of British patents. It is as difficult to withhold admiration of the encyclopaedic scope cjf the matter and references in this book as it is of the erudition and industry displiiyed in its compilation.Practically nothing that comes to mind has escaped atterition, and it is with rather impish glee that the reviewer, after careful search, asserts that he finds no specific reference to the type of alkaline (ammoniacal) gallotannate- iron ink, said t o find favour in the United States, although the di-ammonium hydroxyferrigallate compound of Silbermann and Ozorovitz receives notice. Nor is there mention of that class of quick-drying writing fluids which depend for their efficiency upon partial destruction of the paper sizing by caustic alk 1.5 or sodium silicate. There is no evidence that lignone sulphonate inks have proved se-rious competitors to iron-gall writing inks (pp.15 and 175). Apart from the unkttmwn quantity of permanence, the principal failing of this type lies in their liability to contain traces of free sulphurous acid to which suspicion attaches in connt-ction426 REVIEWS INKS : THEIR COMPOSITION AND MANUFACTURE. By C. AINSWORTH MITCHELL, D.Sc., F.I.C. Fourth Edition. Pp. xi + 408. London: Charles Grihn tt Co., Ltd. 1937. Price 12s. 6d. net. This, the fourth edition of the standard and, indeed, so far as the reviewer’s knowledge goes, the only text-book on the subject in the language, bridges L gap of 13 years. The author, pre-eminent in his particular sphere, needs little more introduction to the world of technical industry than he does in his official capicity to readers of THE ANALYST, while his reputation in forensic science in all that appertains to handwriting is international.The chemistry of ink, difficult as it is and at times not a little obscure, hcl- riot developed markedly in the interval since 1924; but what progress has been made is covered by Dr. Mitchell in this edition in a very thorough manner. He has found it necessary to enlarge his work to the extent of some 20 per cent. and, in addition, to rewrite a large portion. The arrangement of the book follows the lines of previous editions. After a comprehensive historical introduction, the work is divided into three sections dealing with writing inks, printing inks, and inks for miscellaneous purposes, respectively. Under Section 1 are considered the chemical nature and treatment of the various raw materials used for writing inks from lcmp black to galls, the composition of finished iron-gall, logwood, vanadium, aniline black, and coloured inks, as well as a comprehensive scheme €or the tech~ical examination of inks, handwriting specimens and the identification of forge:-ies.Section 2 deals with the manufacture and examination of printing inks. ,tnd Section 3 with the miscellaneous materials entering into the compositilxx of copying, marking, safety, sympathetic, typewriter inks and so on. Amongst new matter may be noted references to the use of lignone sulphni--,ites in connection with writing ink, a scheme for the identification of individual con- stituents in inks in the form of writing, and the application of filtered ultra-.& if )let light and of infra-red photography in the elucidation of those problems to which such methods are suited.The British Government Standard Specificatior:s for Writing Inks, revised in 1928, are included for the first time. The avaihble evidence upon the constitution of gallotannin is brought up to date and <tbly reviewed, and there is a Comprehensive list of British patents. It is as difficult to withhold admiration of the encyclopaedic scope cjf the matter and references in this book as it is of the erudition and industry displiiyed in its compilation. Practically nothing that comes to mind has escaped atterition, and it is with rather impish glee that the reviewer, after careful search, asserts that he finds no specific reference to the type of alkaline (ammoniacal) gallotannate- iron ink, said t o find favour in the United States, although the di-ammonium hydroxyferrigallate compound of Silbermann and Ozorovitz receives notice.Nor is there mention of that class of quick-drying writing fluids which depend for their efficiency upon partial destruction of the paper sizing by caustic alk 1.5 or sodium silicate. There is no evidence that lignone sulphonate inks have proved se-rious competitors to iron-gall writing inks (pp. 15 and 175). Apart from the unkttmwn quantity of permanence, the principal failing of this type lies in their liability to contain traces of free sulphurous acid to which suspicion attaches in connt-ction 6 MILTON AND HOSKINS: THE ESTIMATION OF TRACES OF MERCURY IN URINE The Estimation of Traces of Mercury in'Urine BY R.F. MILTON AND J. L. HOSKINS INTRODUCTION- In the course of an investigation into the effect of mercury upon the health of workers in a thermometer factory and a chemical factory, published elsewhere,l it became necessary to make estimations of the minute quantities of mercury excreted in the urine in such cir- cumst ances. From preliminary work on various methods tried for this purpose, only two seemed at all promising. The method due to Stock and Zimmerman2 was investigated at great length. This consists of oxidation of the urine, electro-deposition of the mercury on a gold electrode, volatilisation from the electrode into a capillary tube, centrifuging of the droplets into a single drop and micro-metric measurement of the diameter of the globule.This technique was found to be so difficult to reproduce, owing to loss of mercury in the glass, film formation, oxidation and so forth, that it was abandoned. The second method involved the use of dithizonc and subsequent colorimetric estimation of the mercury complex. Dithizone undergoes complex formation with a whole range of metals, and its use as an analytical reagent has been admirably expounded by SandelL3 Significantly, a group of metals lying close together in the periodic table are capable of forming dithizonates. These are:- Mn Fe Co Ni Cu Zn Pd Ag Cd In Sn Pt Au Hg Ti Pb Bi Dithizone may form with metals compounds of both keto and enol types, the former containing twice as much metal as the latter.MILTON AND HOSKINS: THE ESTIMATION OF TRACES OF MERCURY IN URINE 7 The enol form generally occurs in alkaline or neutral solution or in absence of an excess of dithizone. Acidification and addition of excess of dithizone usually results in transforma- tion of the metal complex into the keto form.Alternatively, alkalisation may convert it into the enol form. Dithizone readily undergoes oxidation to diphenylthiocarbodiazone, which is always present in the solid reagent as purchased. The oxidation product dissolves in chloroform or similar solvents to give a yellow-brown solution which interferes with colorimetric estimations. It is however insoluble in dilute ammonia and use is made of this fact to purify the com- mercial preparation. (The analyst should always purify his reagent-preferably in small quantities-prior to use, by the method advised by Sandell-see below.) The solution of dithizone is unstable to heat and light and for this reason should be freshly prepared and kept in a darkened container in a cool place. Because traces of oxidising agents and certain metals in alkaline solution cause formation of the carbodiazone, hydroxylamine hydrochloride is added to the aqueous solutions of the metals prior to dithizone treatment, to prevent this occurring.Despite the fact that dithizone reacts to form complexes with so many metals, it may be made almost specific for certain metals by regulating the conditions of reaction. If the acidity of the aqueous solution be adjusted to PH 1.0, then dithizone in chloroform will react with copper, mercury, palladium and silver.This behaviour is the basis of the method here proposed, and the assumption is made that the noble metals are completely absent. APPLICATION OF THE DITHIZONE REAGENT TO THE ESTIMATION OF MERCURY INTERFERING EFFECT OF CoPPER-Copper is always present to an appreciable extent in human urine and biological substances generally and will thus complicate the straightforward estimation of mercury by the direct extraction technique in acid solution (pH 1.0). Various methods have therefore been investigated in an attempt to overcome inter- ference by copper. 1. Addition of potassium iodide to form a complex with mercury--In this method acid potassium iodide solution is added and the dithizone extraction is carried out to remove copper, which does not form a complex iodide under these conditions.Subsequent alkali- sation breaks up the mercury complex, and re-extraction with dithizone allows removal of the mercury. Experiments were carried out to ascertain the optimum conditions for this procedure and to ensure that satisfactory recovery of mercury eventually occurs. Fifty pg. of copper were used in each experiment, and extraction was made with 5-ml. quantities of 0.1 per cent. dithizone solution in chloroform. No. of extractions to give complete removal of copper pH of solution 1.0 to 2.0 10 2.0 to 4-0 6 4.0 to 6.0 3 Thus adequate removal of copper will occur only at about pH 5.0. It was then necessary to ascertain whether satisfactory recovery of mercury could be ensured under these conditions, and a similar experiment was carried out in which mixtures of copper and mercury were extracted.Cu taken Hg taken PH Cu extraction Hg found tLg. f%. Pg. 50 25 5-0 Complete 7 60 50 6.0 $ 9 16 60 25 1.0 Incomplete 18 50 50 1.0 $ D 43 From these experiments it was concluded that copper is not completely extracted by dithizone in presence of potassium iodide unless the fiH of the solution is at least 5-0. At this pH, however, appreciable quantities of mercury are also extracted. 2. Formation of rubeanic acid complex with copper-Copper forms a complex with rubeanic acid, Extraction of copper with dithizone is thus prevented. Experiments with solutions containing copper and mercury (see below) indicate that at PH 1.0 incomplete precipitation of copper results, leading to .enhanced dithizone extraction. If the PH of the8 MILTON AND HOSKINS: THE ESTIMATION OF TRACES OF MERCURY IN URINE solution is increased dithizone will not completely extract mercury, which appears to be adsorbed on the copper complex.Cu taken Hg taken P!+ Clg. 60 26 11 60 I * 25 ,I 60 11 50 I J 20 PH Hg found 1.0 1.0 11 I1 I1 ,I 11 4.0 21 4.0 38 7.2 18 7.2 38 Pg. Copper pptn. incomplete; result masked 3. Removal of mercury as mercuric chloride by extraction with ethw-Mercuric chloride is extracted by ether from acid solutions. Attempts to utilise this property for separation from copper did not meet with complete success. Incomplete recovery of mercury resulted, although three extractions with 20ml. of ether were carried out from 1Oml. of aqueous solution.Hg present Cu present Hg found Cu extracted cCg* M- f% 60 600 46 Nil 50 - 43 - 26 - 23 - 60 - 48 - 4. Selective extraction of mercury by very dilute dithizone solution-In strongly acid solution, preferential complex formation with mercury and the noble metals occurs, if the dithizone i s mt addd in excess. The sudden change in colour indicates the end of the extraction. This method was tested, with various concentrations of hydrochloric acid in the aqu6ous phase. Preliminary investigation indicated that a 0405 per cent. solution of dithizone in chloroform was satisfactory €or extraction] and that shaking 25 ml. of aqueous solution with repeated 2-ml. quantities of this chloroform solution provided a satisfactory technique. Hg present Cu present Concn.of HC1 Hg found Cu effect ILg. Pg. 60 600 0.05 N 50 Contamination of H g colour 60 500 0-076 N 60 nil 60 600 0.10 N 60 nil 60 600 0.20 N 47 nil 60 500 0.30 N 42 nil These results indicate that small quantities of mercury may be selectively extracted from hydrochloric acid solution in the presence of at least ten times the quantity of copper, pro- vided that the solution is more acid than 0.075 N . If, however, the acidity is greater than 0-15 N incomplete removal of mercury results. To confirm the efficiency of the separation and recovery technique, a series of m e r c q solutions containing 0.5 mg. of copper were subjected to the extraction technique and a graph plotted of colour readings against concentrations, using the Spekker absorptiometer fitted with violet filter No.8. The technique was as follows: Solutions containing 0 to 50 pg. of mercury and 0.5 mg. of copper were acidified to 0.1 N with concentrated hydrochloric acid solution. The solution was then extracted with successive l-ml. quantities of a 0.005 per cent. solution of dithizone in chlorofonn until the characteristic golden yellow colour due to mercury dithizonate was no longer exhibited and green colour due to unchanged dithizone was apparent. The combined extracts were made up to 15 ml. with the dithizone solution in chloroform and shaken with two 10 ml. quantities of 5 ber cent. ammonia to remove excess of dithizone. The mercury dithizonate remained in the chloroform layer, but its acid golden brown colour was now changed by the ammonia treatment to the yellow of the keto form, which is the more stable condition.After the chloroform solution had been shaken with exsiccated sodium sulphate and filtered, the absorption was measured in the Spekker photo-electric absorptio- meter. The results are given below; they show this method of procedure to be quite satis- factory. Mercury present, pg. .. .. .. 0 10 20 30 40 50 Spekker reading . . . . . . . . 0.01 0.16 0.26 0.34 0.43 0.62 Reading corrected for blank, x 100 . . - 9 18 27 36 46MILTON AND HOSKINS: THE ESTIMATION OF TRACES OF MERCURY IN URINE APPLICATION OF THE METHOD TO THE ESTIMATION OF MERCURY IN URINE 9 1. OXIDATION OF URINE- Great care must be observed during the oxidation of organic matter to avoid loss of mercury by volatilisation. Whatever oxidation procedure is adopted, the operation is best carried out with use of a reflux condenser and in all-glass apparatus.It is advisable to use a 2-litre flask with a twelve-inch water-cooled condenser fitted in the neck, since the rise in boiling-point due to removal of water predisposes to volatilisation losses. Of the various oxidising procedures tried, that involving the use of sulphuric acid and permanganate was the most rapid and gave the most concordant results. 2. SEPARATION OF MERCURY FROM SOLUTION AS THE SULPHIDE- Prior to estimation with dithizone, it is essential to separate the mercury from the oxidised solution. This is effected by precipitation as the sulphide, ushg another metal of the same group as “collector.” By this technique, a quantity of an appropriate metal salt is added to the solution.On treatment with hydrogen sulphide the minute amount of mer- cury sulphide, which would otherwise remain in colloidal suspension, is co-precipitated. Of the various metals chosen for this purpose, arsenic and antimony were most satisfactory as they do not form dithizonates. At the concentration of acid used for dithizonate extraction, antimony tends to be precipitated as the oxychloride and this results in low mercury re- coveries. Arsenic, however, exhibits no such complications and proved to be excellent for the purpose. The combined sulphides are separated by centrifuging and dissolved in a mixture of nitric and hydrochloric acids. Nitric acid is then destroyed by addition of hy- droxylamine and, after appropriate acidity adjustment, extraction with dithizone solution and estimation of colour follow. 3.RECOMMENDED PROCEDURE- To about 1 litre of urine (preferably a 24-hour collection) in a 2-litre flask, add 100 ml. of sulphuric acid and 20g. of potassium permanganate. Heat gently under reflux for about 2 hours to oxidise organic matter and then decolorise excess of permanganate by careful additions of crystals of oxalic acid. Add 1 ml. of 10 per cent. sodium arsenate solution and pass in hydrogen sulphide for 3 minutes. Then heat the contents of the flask to boiling-point in order to coagulate the precipitate and allow it to settle overnight. Separation of the precipitate is best carried out by centrifuging, first in 250-ml. buckets and then finally concentrating in 16-ml.tubes, but filtration by the filter stick technique may also be used. Wash the precipitate once with water and then dissolve it in 0.4 ml. of nitric and 1 ml. of hydrochloric acids. Warm if necessary to aid solution and to oxidise sulphide to sulphate. Add about 20ml. of water and 1 g. of hydroxylamine hydrochloride and then make up to 100 ml. with water. With strict adherence to this technique, no further additions of acid should be necessary, but it is well to check that the acidity of the solution is of the order of 0.1 N before proceeding to the extraction stage. Next transfer to a separating funnel and shake with successive 1-ml. portions of a freshly prepared 0.005 per cent. solution of purified* dithizone in chloroform, until the golden brown mercury colour is no longer apparent in the chloroform layer.Unite the chloroform extracts and make them up to 15ml. with the dithizone solution (or pro- portions of 15 ml. if more has been added). Remove excess of dithizone by shaking twice with 10 ml. of diluted ammonia (1 in 20). Clarify the chloroform solution by addition of 1 g. of exsiccated sodium sulphate and after filtration read in the Spekker absorptiometer, fitted with violet filter No. 8, and compare with a calibration curve previously prepared from standard solutions of mercury. This method has been used extensively to investigate the toxic effect of mercury metal on workers in a thermometer factory and on workers in a factory preparing mercury salts. * Purijication of dithizone-Dissolve 0.5 g. of dithizone in 50 ml.of chloroform and filter through sintered glass into a dry receiver. Shake with 50ml. of diluted ammonia (1 in 100) and separate from the chloro- form layer. Repeat the ammonia extraction four times, unite the extracts and shake with a small volume of chloroform. After separating and discarding this chloroform washing, make the ammoniacal solution just acid with pure hydrochloric acid to precipitate the dithizone and extract this with four 15-ml. portions of chloro- form. Wash the combined chloroform extracts with two equal quantities of water and evaporate the chloroform off a t about 50” C. Place in an amber tube, seal and store a t low temperature in the dark, Prior to use, about 10 mg. should be repurified by the process described above and the final chloroform solution diluted to the required concentration.10 MILTON AND HOSKINS: THE ESTIMATION OF TRACES OF MERCURY IN URINE The full results and conclusions have been published elsewhere? The following table shows an example of the mercury excretion in these cases and also that of some laboratory workers considered to be normal.URINARY MERCURY EXCRETION FROM WORKERS IN A THERMOMETER FACTORY (Reproduced from Brit.. Jozlm. I d . Med.) Volume per ml. 1040 1600 B. “Contracting” . . .. .. .. 2350 1300 2300 1500 1500 C. “Boiling in” . . . . . . .. 2249 1409 880 1550 1230 D. Finishing . . . . .. .. 1330 1160 900 1200 2250 Operation 24 hours A. Calibrating . , . . .. . . 2200 Workers in factory preparing mercury salts 1000 1900 2400 1900 1400 Normal controls (laboratory workers) . . 2250 750 2500 2600 1800 SUMMARY Mercury present Pg. 175 278 136 2260 500 3478 866 580 2280 1200 2040 1420 1250 730 1700 800 1440 1350 520 750 1360 520 530 23 12 50 65 9 Mercury p.p.m. 0.080 0-267 0.085 0.961 0.385 1.500 0.577 0.433 1.017 0.857 2.329 0-916 1.015 0.561 1.465 0.889 1.200 0.600 0-520 0-395 0-566 0.273 0.378 0-010 0-01 6 0.020 0.025 0.005 (1) A dithizone extraction technique is described for the estimation of small amounts of .mercury in presence of the commonly occurring metals, with special reference to copper. (2) The method is applied to the measurement of the small amounts of mercury that may be found in urine and involves:- (a) Preliminary oxidation of organic matter ; (b) Separation of mercury as the sulphide, with arsenic as ‘‘ collector ”; (c) Extraction of mercury as dithizone complex by means of extremely dilute dithizone solution in the presence of 0.1 N hydrochloric acid; ( d ) Colorimetric estimation of the dithizone complex in chloroform with the Spekker absorptiometer. (3) Results obtained by using this technique on urine from normal persons, workers Part of this work was carried out at the Medical Research Council’s Industrial Medicine in a thermometer factor and workers preparing mercury salts are given. Department, London Hospital. REFERENCES 1. 2. 3. Bucknell, M., Hunter, D., Milton, R., and Perry, K., Brit. Journ. Ind. ,Wed., 1946, 3, 55. Stock, J., and Zimmerman, W., 2. angew. Chem., 1928, 41, 546. Sandell, E. B., “Colorimetric Determination of Traces of Metals,” New York, 1944. 23-24, WELBECK WAY October, 1946 LONDON: W.l

ISSN:0003-2654    

DOI:10.1039/AN9477200006

出版商:RSC    

年代:1947

数据来源: RSC

摘要:

426 REVIEWS INKS : THEIR COMPOSITION AND MANUFACTURE. By C. AINSWORTH MITCHELL, D.Sc., F.I.C. Fourth Edition. Pp. xi + 408. London: Charles Grihn tt Co., Ltd. 1937. Price 12s. 6d. net. This, the fourth edition of the standard and, indeed, so far as the reviewer’s knowledge goes, the only text-book on the subject in the language, bridges L gap of 13 years. The author, pre-eminent in his particular sphere, needs little more introduction to the world of technical industry than he does in his official capicity to readers of THE ANALYST, while his reputation in forensic science in all that appertains to handwriting is international. The chemistry of ink, difficult as it is and at times not a little obscure, hcl- riot developed markedly in the interval since 1924; but what progress has been made is covered by Dr.Mitchell in this edition in a very thorough manner. He has found it necessary to enlarge his work to the extent of some 20 per cent. and, in addition, to rewrite a large portion. The arrangement of the book follows the lines of previous editions. After a comprehensive historical introduction, the work is divided into three sections dealing with writing inks, printing inks, and inks for miscellaneous purposes, respectively. Under Section 1 are considered the chemical nature and treatment of the various raw materials used for writing inks from lcmp black to galls, the composition of finished iron-gall, logwood, vanadium, aniline black, and coloured inks, as well as a comprehensive scheme €or the tech~ical examination of inks, handwriting specimens and the identification of forge:-ies.Section 2 deals with the manufacture and examination of printing inks. ,tnd Section 3 with the miscellaneous materials entering into the compositilxx of copying, marking, safety, sympathetic, typewriter inks and so on. Amongst new matter may be noted references to the use of lignone sulphni--,ites in connection with writing ink, a scheme for the identification of individual con- stituents in inks in the form of writing, and the application of filtered ultra-.& if )let light and of infra-red photography in the elucidation of those problems to which such methods are suited. The British Government Standard Specificatior:s for Writing Inks, revised in 1928, are included for the first time. The avaihble evidence upon the constitution of gallotannin is brought up to date and <tbly reviewed, and there is a Comprehensive list of British patents.It is as difficult to withhold admiration of the encyclopaedic scope cjf the matter and references in this book as it is of the erudition and industry displiiyed in its compilation. Practically nothing that comes to mind has escaped atterition, and it is with rather impish glee that the reviewer, after careful search, asserts that he finds no specific reference to the type of alkaline (ammoniacal) gallotannate- iron ink, said t o find favour in the United States, although the di-ammonium hydroxyferrigallate compound of Silbermann and Ozorovitz receives notice. Nor is there mention of that class of quick-drying writing fluids which depend for their efficiency upon partial destruction of the paper sizing by caustic alk 1.5 or sodium silicate.There is no evidence that lignone sulphonate inks have proved se-rious competitors to iron-gall writing inks (pp. 15 and 175). Apart from the unkttmwn quantity of permanence, the principal failing of this type lies in their liability to contain traces of free sulphurous acid to which suspicion attaches in connt-ction426 REVIEWS INKS : THEIR COMPOSITION AND MANUFACTURE. By C. AINSWORTH MITCHELL, D.Sc., F.I.C. Fourth Edition. Pp. xi + 408. London: Charles Grihn tt Co., Ltd. 1937. Price 12s. 6d. net. This, the fourth edition of the standard and, indeed, so far as the reviewer’s knowledge goes, the only text-book on the subject in the language, bridges L gap of 13 years. The author, pre-eminent in his particular sphere, needs little more introduction to the world of technical industry than he does in his official capicity to readers of THE ANALYST, while his reputation in forensic science in all that appertains to handwriting is international.The chemistry of ink, difficult as it is and at times not a little obscure, hcl- riot developed markedly in the interval since 1924; but what progress has been made is covered by Dr. Mitchell in this edition in a very thorough manner. He has found it necessary to enlarge his work to the extent of some 20 per cent. and, in addition, to rewrite a large portion. The arrangement of the book follows the lines of previous editions. After a comprehensive historical introduction, the work is divided into three sections dealing with writing inks, printing inks, and inks for miscellaneous purposes, respectively.Under Section 1 are considered the chemical nature and treatment of the various raw materials used for writing inks from lcmp black to galls, the composition of finished iron-gall, logwood, vanadium, aniline black, and coloured inks, as well as a comprehensive scheme €or the tech~ical examination of inks, handwriting specimens and the identification of forge:-ies. Section 2 deals with the manufacture and examination of printing inks. ,tnd Section 3 with the miscellaneous materials entering into the compositilxx of copying, marking, safety, sympathetic, typewriter inks and so on. Amongst new matter may be noted references to the use of lignone sulphni--,ites in connection with writing ink, a scheme for the identification of individual con- stituents in inks in the form of writing, and the application of filtered ultra-.& if )let light and of infra-red photography in the elucidation of those problems to which such methods are suited.The British Government Standard Specificatior:s for Writing Inks, revised in 1928, are included for the first time. The avaihble evidence upon the constitution of gallotannin is brought up to date and <tbly reviewed, and there is a Comprehensive list of British patents. It is as difficult to withhold admiration of the encyclopaedic scope cjf the matter and references in this book as it is of the erudition and industry displiiyed in its compilation.Practically nothing that comes to mind has escaped atterition, and it is with rather impish glee that the reviewer, after careful search, asserts that he finds no specific reference to the type of alkaline (ammoniacal) gallotannate- iron ink, said t o find favour in the United States, although the di-ammonium hydroxyferrigallate compound of Silbermann and Ozorovitz receives notice. Nor is there mention of that class of quick-drying writing fluids which depend for their efficiency upon partial destruction of the paper sizing by caustic alk 1.5 or sodium silicate. There is no evidence that lignone sulphonate inks have proved se-rious competitors to iron-gall writing inks (pp. 15 and 175). Apart from the unkttmwn quantity of permanence, the principal failing of this type lies in their liability to contain traces of free sulphurous acid to which suspicion attaches in connt-ction426 REVIEWS INKS : THEIR COMPOSITION AND MANUFACTURE.By C. AINSWORTH MITCHELL, D.Sc., F.I.C. Fourth Edition. Pp. xi + 408. London: Charles Grihn tt Co., Ltd. 1937. Price 12s. 6d. net. This, the fourth edition of the standard and, indeed, so far as the reviewer’s knowledge goes, the only text-book on the subject in the language, bridges L gap of 13 years. The author, pre-eminent in his particular sphere, needs little more introduction to the world of technical industry than he does in his official capicity to readers of THE ANALYST, while his reputation in forensic science in all that appertains to handwriting is international. The chemistry of ink, difficult as it is and at times not a little obscure, hcl- riot developed markedly in the interval since 1924; but what progress has been made is covered by Dr.Mitchell in this edition in a very thorough manner. He has found it necessary to enlarge his work to the extent of some 20 per cent. and, in addition, to rewrite a large portion. The arrangement of the book follows the lines of previous editions. After a comprehensive historical introduction, the work is divided into three sections dealing with writing inks, printing inks, and inks for miscellaneous purposes, respectively. Under Section 1 are considered the chemical nature and treatment of the various raw materials used for writing inks from lcmp black to galls, the composition of finished iron-gall, logwood, vanadium, aniline black, and coloured inks, as well as a comprehensive scheme €or the tech~ical examination of inks, handwriting specimens and the identification of forge:-ies.Section 2 deals with the manufacture and examination of printing inks. ,tnd Section 3 with the miscellaneous materials entering into the compositilxx of copying, marking, safety, sympathetic, typewriter inks and so on. Amongst new matter may be noted references to the use of lignone sulphni--,ites in connection with writing ink, a scheme for the identification of individual con- stituents in inks in the form of writing, and the application of filtered ultra-.& if )let light and of infra-red photography in the elucidation of those problems to which such methods are suited. The British Government Standard Specificatior:s for Writing Inks, revised in 1928, are included for the first time.The avaihble evidence upon the constitution of gallotannin is brought up to date and <tbly reviewed, and there is a Comprehensive list of British patents. It is as difficult to withhold admiration of the encyclopaedic scope cjf the matter and references in this book as it is of the erudition and industry displiiyed in its compilation. Practically nothing that comes to mind has escaped atterition, and it is with rather impish glee that the reviewer, after careful search, asserts that he finds no specific reference to the type of alkaline (ammoniacal) gallotannate- iron ink, said t o find favour in the United States, although the di-ammonium hydroxyferrigallate compound of Silbermann and Ozorovitz receives notice.Nor is there mention of that class of quick-drying writing fluids which depend for their efficiency upon partial destruction of the paper sizing by caustic alk 1.5 or sodium silicate. There is no evidence that lignone sulphonate inks have proved se-rious competitors to iron-gall writing inks (pp. 15 and 175). Apart from the unkttmwn quantity of permanence, the principal failing of this type lies in their liability to contain traces of free sulphurous acid to which suspicion attaches in connt-ction MILTON AND DUFFIELD: THE ESTIMATION OF MERCURY COMPOUNDS IN THE ATMOSPHERE 11 The Estimation of Mercury Compounds in the Atmosphere BY R. F. MILTON AND W. D. DUFFIELD THE sampling of mercury in the air involves two distinct problems according to whether the mercury is present as vapour or in particulate form.Mercury vapour has been estimated by a number of methods, all of which have some disadvantages. These are well summarised by Jacobs.1 A method that involves trapping the mercury vapour in aqua regia has been criticised by Norlander2 on the grounds that the mercuric chloride which fonns becomes particulate and passes through solutions as mist. Of the other trapping methods may be mentioned that of Pyankoff,* which relies on the action of iodine crystals in the curve of a U-tube to combine with the mercury, that of Polejaeff: in which absorption in iodine and potassium iodide is used, and that of Moldav~ky,~ which utilises gaseous bromine as fixative.All these methods are apt to give incomplete absorption and recovery if the mercury concentrations in the air are low and if the flow rate is raised to practical magnitudes. In the method used by Stocks the air is passed through a tube chilled with either liquid air or carbon- dioxide-snow and ether. The mercury metal so con- densed is dissolved in chlorine water and subsequently estimated. With this method we have found great difficulty in disposing of the large volume of ice that separates in the U-tube and have consistently lost some of the mercury in the process. Filter papers impregnated with selenium sulphide' have also been used for estimating mercury vapours, the air being drawn through at a fairly rapid rate. The degree of darkening of the paper indicates the mercury concentration. In this method (a) the temperature must be raised to 70" C.for the reaction to occur, and (b) it is certain that trapping is incomplete. Photo-electric methods are available involving measurement of the scattering of the resonance radiation of mercury by mercury vapour.8 The appara- tus, when procurable, is costly. Mercury salts-These are not accurately estimated by any of the above methods, and therefore when they co-exist with mercury vapour in the atmosphere a specialised technique is necessary. Substances in particulate form in the air, if above a certain particle size, are not trapped in a satisfactory manner by absorption in liquids, as may be readily demon- strated by blowing tobacco smoke into water. Where the particle size is above the limits allowing of absorption by liquids, it is best to use a filter paper through which the air is drawn to absorb the substance.With mercury salts, where the vapour pressure is con- siderable, absorption on a filter would be accompanied by volatilisation as aspiration proceeded. The loss that this would entail may be overcome by backing the filter with a liquid scrubbing device. Th'is is essential if mercury vapour is also present. The arrangement shown in Fig. 1 is satisfactory for the purpose. The particle filter (a Whatman No. 3) is held in a device such as is used by Fairhall and Sayersg for the estimation of lead fumes. This is connected by butted glass tubes to a bead absorption bubbler as described by Miltonlo for the estimation of benzene in the air.ABSORPTION OF MERCURY VAPOUR- In order to remove mercury vapour from the air it is first essential to oxidise and fix it as a salt so as to allow of absorption in liquids. We have found alkaline hypobromite to be very satisfactory for this purpose. A solution was prepared by dissolving 4ml. of bromine in 100 ml. of 8 per cent. sodium hydroxide solution, and 5 ml. of this solution were introduced into the absorption bubbler shown in the figure. Three such bubblers were N GAS-ABSORBING12 MILTON AND DUFFIELD: THE ESTIMATION OF MERCURY COMPOUNDS IN THE ATMOSPHERE connected in a series, in front of which was connected a tube containing a little metallic mercury. Air was aspirated over the mercury and through the system at a rate of 2 litres per minute for about 60 minutes, and the mercury-laden atmosphere was thus drawn through the absorption tubes.The contents of each bubbler and the filter were analysed separately for mercury; results are shown in Table I. TABLE I Hg in 1st Experiment bubbler Pg- 1 408 2 340 3 460 4 125 5 345 Hg in 2nd bubbler Pg. 42 30 37 12 20 Slip from 1st bubbler 10 9 8 10 6 % The slip from the first bubbler is approximately 10 per cent. and this is of the order usually obtained in absorption apparatus of this type. For accurate work it is therefore desirable practice to use two such bubblers in series. In this absorption system the brownish-yellow hypobromite solution gradually becomes decolorised. This fact does not appear to influence the absorption of the mercury vapour, as is evidenced by Table 11.In these experiments three bubblers in series were charged with hypobromite and aspirated with mercury-free air until the solution was decolorised. The apparatus was then connected to a tube containing metallic mercury and air was aspirated through the system. It will be seen that absorption is similar to that with fresh hypobromite solution, as shown in Table I. TABLE I1 Pg. Experiment Hg in 1st bubbler Hg in 2nd bubbler 1 350 25 2 410 34 3 340 21 ABSORPTION OF MERCURY SALTS- The particulate nature of mercury salts makes their absorption in liquids an incomplete operation, since particles between 5pand 25p may pass through. On the other hand, the use of a filter paper of low resistance in the apparatus mentioned above is very effective for this purpose.In view, however, of the relatively high vapour pressure of the mercury halides, the continual passage of air through the filter results in losses by volatilisation. I t is therefore essential to back the particle filter with a liquid absorption device. ESTIMATION OF MERCURY AFTER ABSORPTION- (a) Mercury vapour-Transfer the hypobromite solution containing the mercury to a flask, and rinse out the bubbler three or four times with 5 ml. of water to ensure quantitative transference. Then acidify the solution with a few drops of hydrochloric acid, whereupon the colour turns brown owing to liberation of free bromine. Add, drop by drop, a 50 per cent. aqueous solution of hydroxylamine hydrochloride until the bromine is decolorised. Introduce a small piece of litmus paper into the flask and add dilute sodium hydroxide solution drop by drop until the liquid is just neutral.Then add hydrochloric acid until the acidity of the solu- tion is 0.1 N . At this stage the solution (or an aliquot) is ready for estimation of mercury by the dithizone colour method described below. (b) Mercury in particulate forms-Transfer the filter paper containing the mercury salts to a small beaker and extract it for about 10 minutes with 2 to 5 ml. of aqua regia on a boiling water bath. Pour the acid mass on a sintered filter-, or dilute and pour it on to a filter paper, and wash thoroughly, using up to 60 ml. of distilled water for the purpose. To the solution add about 5 ml. of 50 per cent. hydroxylamine hydrochloride solution to destroy nitric com- pounds and then carefully neutralise the solution, using first 40 per cent.and finally 1 per cent. sodium hydroxide solution. Then add so much hydrochloric acid that the acidity of the solution is eventually 0.1 N , and carry out the dithizone colour estimztion as described below. (c) Colorimetric estimation of mercuyy-This is in accordance with the method of Milton and Hoskins previously describedJ1 Shake the solution containing mercury in 0-1 N hydro- chloric acid with successive l-ml. quantities of a 0.005 per cent. solution of purified dithizone in chloroform until the golden colour due to mercury dithizonate is replaced by the greenMILTON AND DUFFIELD : THE ESTIMATION OF MERCURY COMPOUNDS IN THE ATMOSPHERE 13 colour due to excess of reagent. Combine the chloroform extracts, make them up to 16 ml.(or an aliquot) and wash with diluted ammonia (1 in 20) in order to remove‘excess of dithizone. Then clarify the chloroform extract by shaking it with anhydrous sodium sulphate, filter it, and measure the absorption in a Spekker absorptiometer, using the violet filter No. 8. Refer the result to a graph constructed from readings obtained from standard solutions of mercury submitted to the above extraction technique. The method was devised in order to carry out estimations of mercury vapour in a ther- mometer factory and in a factory preparing mercury salts.12 A few of these results are reproduced in Table 111. TABLE I11 (1) ESTIMATIONS OF MERCURY VAPOUR IN AIR (Thermometer factory) Site of mercury Concentration pg. per cubic metre (a) In general shop .... .. .. .. 25 (b) Where mercury is boiled in stems to remove air . . 100 108 (c) Where mercury is centrifuged into glass stems . . 175 70 670 220 Multiple results represent findings on different days (2) ESTIMATION OF MERCURY SALTS AND MERCURY VAPOUR IN AIR (Factory manufacturing mercury salts) Concentration of Hg Site pg. per cubic metre (a) Weighing booth (Hg metal) .. .. . . . . “Vapour” 185 “Particulate” nil (b) Preparation of mercury oxide and mercury iodide . . “Vapour” 150 “Particulate” 130 (c) In sieving room . . .. .. .. .. . . “Vapour” 160 ‘ ‘Particulate’ ’ 18,000 (d) In sublimate manufacturing room . . .. . . “Vapour” 125 “Particulate” 230 ( e ) In sublimate packing room . . .. .. . . “Vapour” 126 “Particulate” 540 SUMMARY (1) Methods for the estimation of mercury in the air have been discussed. (2) A new method using alkaline hypobromite for the trapping of mercury vapour is described. (3) The collection of particulate mercury in air is also described. (4) The subsequent estimation of mercury in the samples is outlined. (5) The method has been applied to the estimation of mercury vapour and mercury Part of this work was carried out at the Medical Research Council‘s Industrial Medicine salts in factory air, and some results are tabulated. Department , London Hospital. REFERENCES I. 2. 3. 4. 6. 6. 7. 8. 9. 10. 11. 12. Jacobs, M. B., “The Analytical Chemistry of Industrial Poisons, Hazards and Solvents,” New York, Nordlander, B. W., Ind. Eng. Chem., 1927, 19, 518, 522. Pyankoff, V. A., J . Applied Chem., U.S.S.R., 580; Chem. Abstr., 1936,30, 7488. Polejaeff, see Jacobs, Ref. 1, p. 190. Moldavsky, B. L., Zhur. Prikladnoi. Khim., 1930, 3, 955. Stock, A., and Cucuel, F., Bey., 1934, 6 7 ~ , 122. Biggs, L. R., J . Ind. Hyg. Toxicol., 1938, 20, 161. Burke, W. J., Moskowitz, S., and Dolin, New York State Ind. Bull., 1939, 18, 235. Fairhall, L. T., and Sayers, R. R., U.S. Pub. Health Service, 1940, Bull. No. 253. Milton, R. F., Brit. Journ. Ind. Med., 1945, 2, 36. Milton, R. F., and Hoskins, J.. ANALYST, 1947, 72, 6. Bucknell, M., Hunter, D., Milton, R. F., and Perry, K., Brit. Journ. Ind. Med., 1946,3, p. 66. 1944, p. 183. 23-24, WELBECK WAY October, 1946 LONDON, W.l

ISSN:0003-2654    

DOI:10.1039/AN9477200011

出版商:RSC    

年代:1947

数据来源: RSC

摘要:

426 REVIEWS INKS : THEIR COMPOSITION AND MANUFACTURE. By C. AINSWORTH MITCHELL, D.Sc., F.I.C. Fourth Edition. Pp. xi + 408. London: Charles Grihn tt Co., Ltd. 1937. Price 12s. 6d. net. This, the fourth edition of the standard and, indeed, so far as the reviewer’s knowledge goes, the only text-book on the subject in the language, bridges L gap of 13 years. The author, pre-eminent in his particular sphere, needs little more introduction to the world of technical industry than he does in his official capicity to readers of THE ANALYST, while his reputation in forensic science in all that appertains to handwriting is international. The chemistry of ink, difficult as it is and at times not a little obscure, hcl- riot developed markedly in the interval since 1924; but what progress has been made is covered by Dr.Mitchell in this edition in a very thorough manner. He has found it necessary to enlarge his work to the extent of some 20 per cent. and, in addition, to rewrite a large portion. The arrangement of the book follows the lines of previous editions. After a comprehensive historical introduction, the work is divided into three sections dealing with writing inks, printing inks, and inks for miscellaneous purposes, respectively. Under Section 1 are considered the chemical nature and treatment of the various raw materials used for writing inks from lcmp black to galls, the composition of finished iron-gall, logwood, vanadium, aniline black, and coloured inks, as well as a comprehensive scheme €or the tech~ical examination of inks, handwriting specimens and the identification of forge:-ies.Section 2 deals with the manufacture and examination of printing inks. ,tnd Section 3 with the miscellaneous materials entering into the compositilxx of copying, marking, safety, sympathetic, typewriter inks and so on. Amongst new matter may be noted references to the use of lignone sulphni--,ites in connection with writing ink, a scheme for the identification of individual con- stituents in inks in the form of writing, and the application of filtered ultra-.& if )let light and of infra-red photography in the elucidation of those problems to which such methods are suited. The British Government Standard Specificatior:s for Writing Inks, revised in 1928, are included for the first time. The avaihble evidence upon the constitution of gallotannin is brought up to date and <tbly reviewed, and there is a Comprehensive list of British patents.It is as difficult to withhold admiration of the encyclopaedic scope cjf the matter and references in this book as it is of the erudition and industry displiiyed in its compilation. Practically nothing that comes to mind has escaped atterition, and it is with rather impish glee that the reviewer, after careful search, asserts that he finds no specific reference to the type of alkaline (ammoniacal) gallotannate- iron ink, said t o find favour in the United States, although the di-ammonium hydroxyferrigallate compound of Silbermann and Ozorovitz receives notice. Nor is there mention of that class of quick-drying writing fluids which depend for their efficiency upon partial destruction of the paper sizing by caustic alk 1.5 or sodium silicate.There is no evidence that lignone sulphonate inks have proved se-rious competitors to iron-gall writing inks (pp. 15 and 175). Apart from the unkttmwn quantity of permanence, the principal failing of this type lies in their liability to contain traces of free sulphurous acid to which suspicion attaches in connt-ction426 REVIEWS INKS : THEIR COMPOSITION AND MANUFACTURE. By C. AINSWORTH MITCHELL, D.Sc., F.I.C. Fourth Edition. Pp. xi + 408. London: Charles Grihn tt Co., Ltd. 1937. Price 12s. 6d. net. This, the fourth edition of the standard and, indeed, so far as the reviewer’s knowledge goes, the only text-book on the subject in the language, bridges L gap of 13 years. The author, pre-eminent in his particular sphere, needs little more introduction to the world of technical industry than he does in his official capicity to readers of THE ANALYST, while his reputation in forensic science in all that appertains to handwriting is international.The chemistry of ink, difficult as it is and at times not a little obscure, hcl- riot developed markedly in the interval since 1924; but what progress has been made is covered by Dr. Mitchell in this edition in a very thorough manner. He has found it necessary to enlarge his work to the extent of some 20 per cent. and, in addition, to rewrite a large portion. The arrangement of the book follows the lines of previous editions. After a comprehensive historical introduction, the work is divided into three sections dealing with writing inks, printing inks, and inks for miscellaneous purposes, respectively.Under Section 1 are considered the chemical nature and treatment of the various raw materials used for writing inks from lcmp black to galls, the composition of finished iron-gall, logwood, vanadium, aniline black, and coloured inks, as well as a comprehensive scheme €or the tech~ical examination of inks, handwriting specimens and the identification of forge:-ies. Section 2 deals with the manufacture and examination of printing inks. ,tnd Section 3 with the miscellaneous materials entering into the compositilxx of copying, marking, safety, sympathetic, typewriter inks and so on. Amongst new matter may be noted references to the use of lignone sulphni--,ites in connection with writing ink, a scheme for the identification of individual con- stituents in inks in the form of writing, and the application of filtered ultra-.& if )let light and of infra-red photography in the elucidation of those problems to which such methods are suited.The British Government Standard Specificatior:s for Writing Inks, revised in 1928, are included for the first time. The avaihble evidence upon the constitution of gallotannin is brought up to date and <tbly reviewed, and there is a Comprehensive list of British patents. It is as difficult to withhold admiration of the encyclopaedic scope cjf the matter and references in this book as it is of the erudition and industry displiiyed in its compilation.Practically nothing that comes to mind has escaped atterition, and it is with rather impish glee that the reviewer, after careful search, asserts that he finds no specific reference to the type of alkaline (ammoniacal) gallotannate- iron ink, said t o find favour in the United States, although the di-ammonium hydroxyferrigallate compound of Silbermann and Ozorovitz receives notice. Nor is there mention of that class of quick-drying writing fluids which depend for their efficiency upon partial destruction of the paper sizing by caustic alk 1.5 or sodium silicate. There is no evidence that lignone sulphonate inks have proved se-rious competitors to iron-gall writing inks (pp. 15 and 175). Apart from the unkttmwn quantity of permanence, the principal failing of this type lies in their liability to contain traces of free sulphurous acid to which suspicion attaches in connt-ction426 REVIEWS INKS : THEIR COMPOSITION AND MANUFACTURE.By C. AINSWORTH MITCHELL, D.Sc., F.I.C. Fourth Edition. Pp. xi + 408. London: Charles Grihn tt Co., Ltd. 1937. Price 12s. 6d. net. This, the fourth edition of the standard and, indeed, so far as the reviewer’s knowledge goes, the only text-book on the subject in the language, bridges L gap of 13 years. The author, pre-eminent in his particular sphere, needs little more introduction to the world of technical industry than he does in his official capicity to readers of THE ANALYST, while his reputation in forensic science in all that appertains to handwriting is international. The chemistry of ink, difficult as it is and at times not a little obscure, hcl- riot developed markedly in the interval since 1924; but what progress has been made is covered by Dr.Mitchell in this edition in a very thorough manner. He has found it necessary to enlarge his work to the extent of some 20 per cent. and, in addition, to rewrite a large portion. The arrangement of the book follows the lines of previous editions. After a comprehensive historical introduction, the work is divided into three sections dealing with writing inks, printing inks, and inks for miscellaneous purposes, respectively. Under Section 1 are considered the chemical nature and treatment of the various raw materials used for writing inks from lcmp black to galls, the composition of finished iron-gall, logwood, vanadium, aniline black, and coloured inks, as well as a comprehensive scheme €or the tech~ical examination of inks, handwriting specimens and the identification of forge:-ies.Section 2 deals with the manufacture and examination of printing inks. ,tnd Section 3 with the miscellaneous materials entering into the compositilxx of copying, marking, safety, sympathetic, typewriter inks and so on. Amongst new matter may be noted references to the use of lignone sulphni--,ites in connection with writing ink, a scheme for the identification of individual con- stituents in inks in the form of writing, and the application of filtered ultra-.& if )let light and of infra-red photography in the elucidation of those problems to which such methods are suited. The British Government Standard Specificatior:s for Writing Inks, revised in 1928, are included for the first time.The avaihble evidence upon the constitution of gallotannin is brought up to date and <tbly reviewed, and there is a Comprehensive list of British patents. It is as difficult to withhold admiration of the encyclopaedic scope cjf the matter and references in this book as it is of the erudition and industry displiiyed in its compilation. Practically nothing that comes to mind has escaped atterition, and it is with rather impish glee that the reviewer, after careful search, asserts that he finds no specific reference to the type of alkaline (ammoniacal) gallotannate- iron ink, said t o find favour in the United States, although the di-ammonium hydroxyferrigallate compound of Silbermann and Ozorovitz receives notice.Nor is there mention of that class of quick-drying writing fluids which depend for their efficiency upon partial destruction of the paper sizing by caustic alk 1.5 or sodium silicate. There is no evidence that lignone sulphonate inks have proved se-rious competitors to iron-gall writing inks (pp. 15 and 175). Apart from the unkttmwn quantity of permanence, the principal failing of this type lies in their liability to contain traces of free sulphurous acid to which suspicion attaches in connt-ction 14 SMALES: THE PRECIPITATION OF ALUMINIUM AND ITS SEPARATION FROM The Precipitation of Aluminium and its Separation from Cobalt, Chromium, Nickel or Zinc by means of Ammonium Benzoate BY A. A.SMALES INTRODUCTION- The analysis of materials containing aluminium together with cobalt, chromium, nickel or zinc is often required. The classical method of separation of these metals from aluminium is to remove them from a sulphuric or perchloric acid solution by electrolysis with a mercury cathode. This procedure is time-consuming, however, and a direct precipita- tion of the aluminium would be preferable. Precipitation with ammonium hydroxide (in the case of chromium after oxidation of CrlI1 to- CrV1) is ruled out because occlusion by alu- minium hydroxide makes repeated precipitations necessary. Several other direct precipitants have been suggested, but of these only ammonium benzoate1p2ss appeared to be suitable for our purpose. This ammonium benzoate precipitation has been attempted at Billingham on one or two occasions previously and, although some good results have been obtained, a few were poor, and hence no confidence could be placed in the procedure used, which was that of Kolthoff .l Thus it was first necessary to standardise conditions of precipitation.The use of benzoate for sephration of aluminium from chromium does not appear to have been mentioned previously and it was therefore necessary to determine the efficiency of the separation. It was considered also that a more direct method of determining the cobalt, nickel and zinc in the final alumina would be preferable to Kolthoff’s indirect method. (1) PRECIPITATION CONDITIONS- Instructions given by Kolthoff (“ cautiously neutralise with dilute ammonia solution until the precipitate redissolves very slowly, then add 1 ml.of glacial acetic acid and 1 g . of ammonium chloride”), allow a fairly wide variation in the pH at which precipitation takes place. A standard aluminium solution containing approximately 1 mg. of aluminium per ml. was prepared from ammonium alum and standardised gravimetrically by precipitation with ammonium hydroxide; 50 ml. gave 93.0 mg. of alumina. Several 50-ml. lots were measured out and diluted to 100ml., and to each was added a solution containing 1 g . of ammonium chloride and 2 g. of ammonium benzoate. The pH of each was adjusted by addition of N hydrochloric acid or ammonia in the cold, to give values of 2.5, 3, 3.5, 4, 5, 5.5, 6 and 7, respectively. (The fiH was measured by means of a Marconi-Ekco pH meter with glass electrode.) The solutions were then boiled, the precipi- tates were allowed to settle for 30 minutes, filtered through 12.5-cm.Whatman No. 40 papers and washed with a warm solution containing 10 g. of ammonium benzoate and 20 ml. of glacial acetic acid per litre. They were ignited to constant weight, first in a muffle furnace, and finally over a blast lamp. The weights of alumina so obtained are shown in Table I. EXPERIMENTAL Therefore the first step was to find the optimum pH for precipitation. TABLE I EFFECT OF VARIATION OF $H ON THE PRECIPITATION OF ALUMINIUM BENZOATE PH value . . 2.5 3 3.5 4 5 5.5 6 7 AZO,, mg. . . 70-9 85.2 93.2 93.0 93.0 93.0 93.5 93.3 The appearance of the precipitates at the various pH values was informative.Those at pH 2-5, 3 and 3.5 gave trouble owing to crystallisation of benzoic acid during filtration. Those at fiH 4 and 5 were granular and filtered easily, whilst those at pH 5.5, 6 and 7 became gelatinous and difficult to filter-apparently the hydroxide, and not the benzoate, began to form the major part of the precipitate at these higher fiH values. Thus, the optimum PH range is from 3.5 to 5, preferably 4, as occlusion of other ions might be expected to be least at the lower pH. For routine work an easier method of pH control than the use of a glass electrode PH meter was desirable. Hence bromophenol blue ($H 3-3.6) was used as indicator in subsequentCOBALT, CHROMIUM, NICKEL OR ZINC BY MEANS OF AMMONIUM BENZOATE 15 work, although for information the $H value of all filtrates was also measured by theglass electrode pH meter.The next step was to carry out benzoate precipitations on pure aluminium solutions, with bromophenol blue as indicator, to confirm that (a) quantitative results, and (b) adequate pH control, were obtainable. Table I1 shows results of experiments in which 25- and 50-ml. lots of the standard aluminium solution were treated with 1 g. of ammonium chloride and 2 g. of ammonium benzoate, acidified, heated and then treated with dilute ammonia from a burette until just blue to bromophenol blue. The solutions were boiled and filtered and the pre- cipitates ignited as before. TABLE I1 fiH CONTROL AND ALUMINIUM RECOVERY WHEN BROMOPHENOL BLUE INDICATOR WAS USED Std. A1 solution, ml. A&O, recovered, mg.PH of filtrate 26 46-4 5.6 25 46-5 4.8 50 92.6 6-4 60 93.0 6-1 Thus although quantitative results were obtained pH control (and presumably therefore occlusion control) was poor. It was therefore necessary to have more buffering capacity in the PH 4 range;’so in the following precipitations 2 g. of ammonium acetate were added in addition to the 1 g. of am- monium chloride and 2 g. of ammonium benzoate. The conditions of precipitation were also standardised to give consistently a granular, rapidly filterable precipitate. The conditions under which this occurs result from the following procedure :-To the slightly acid (usually hy- drochloric acid) solution containing aluminium, of volume 250-300 ml., add 1 g. of ammonium chloride, 20 ml. of 10 per cent. ammonium acetate solution, 20 ml.of 10 per cent. ammonium benzoate solution and 2 ml. of bromophenol blue indicator solution. * Heat to 80” C., add sufficient hydrochloric acid to dissolve any precipitated aluminium benzoate (the benzoic acid, which precipitates in the cold, is soluble at 80” C.) and add dilute ammonia from a burette slowly, and with shaking, until the indicator just begins to change colour and precipitation just begins. At this point, boil the solution for one or two minutes, whereupon further precipitation takes place giving a granular precipitate. Usually at this point the solution becomes just acid again. Continue the addition of dilute ammonia from the burette until the indicator just gives the red-blue colour characteristic of $H 3.5 to 4. Boil the solution gently for 2-3 minutes and place on a water bath for 30 minutes to allow the precipitate to settle.Filter through a Whatman No. 40 paper and wash 10 times with hot wash liquor containing 10 g. of ammonium benzoate and 20 ml. of glacial acetic acid per litre ($H 3.8). Results of precipitations carried out under these conditions are shown in Table 111, EiOml. of the standard aluminium solution being used. TABLE I11 pH CONTROL AND ALUMINIUM RECOVERY UNDER NEW CONDITIONS OF PRECIPITATION AbO, recovered, mg.. . 93.6 93.0 92-8 93.0 p H of filtrate . . 3.6 3.8 4.05 4.0 Thus, $H control now appeared satisfactory. Results of experiments involving separations, described below, give further evidence of this. 2. SEPARATIONS- The efficiency of separations was measured (a) by weighing the alumina after ignition of the benzoate precipitate to constant weight and (b) by polarographic determinations (see Note 1) of the “contaminating” metal after fusion of the “contaminated” alumina with 2g.of potassium hydrogen sulphate. The fusions containing chromium, nickel or zinc were dissolved in water, diluted to 100 ml. and polarographed over a suitable voltage range. (Two or three drops of sulphurous acid were added to the chromium solution and excess was boiled off, to make quite certain that chromium was present as Cr”‘). The fusions containing cobalt were dissolved in water, 1 g. of tartaric acid was added and the solution made am- moniacal before dilution to 1OOml. In all four cases standard polarograms were obtained for known amounts of the metals under similar conditions.That is, for chromium, nickel or zinc, four lots of 2 g. of potassium hydrogen sulphate and 50 mg. of aluminium as alumina were fused, and to the dissolved fusions were added 0,06, 1 and 2 mg. of the metal in question (as the sulphate) before diluting; for cobalt the dissolved fusions wei-e made ammoniacal after addition of 1 g. of tartaric acid and 0, 0.5, 1 and 2 mg. of cobalt (also as sulphate) and then diluted to 100ml.16 SMALES: THE PRECIPITATION OF ALUMINIUM BY AMMONIUM BENZOATE In each experiment two lots of 50 ml. (= 93.0 mg. of alumina) of the standard aluminium solution were taken, together with 50 and 100mg. respectively of the metal in question, chromium as potassium dichromate (see Note 2), and cobalt, nickel and zinc as sulphates; precipitation was carried out as described above. Table IV gives the results obtained.TABLE IV SEPARATION OF ALUMINIUM FROM COBALT, CHROMIUM~', NICKEL OR ZINC BY MEANS OF A SINGLE AMMONIUM BENZOATE PRECIPITATION Wt. of oxide obtained, Wt. of alien metal (not Alien mg. (should be 93.0 oxide) determined PH of metal, mg. for perfect separation) polarographically, mg. filtrate 50 Co 92-8 0.1 3.65 100 ,, 93.4 0.1 3.7 60 Crv* 93.2 0.1 3.8 100 *, 93.4 0.1 3.8 50 Ni 93.4 0.5 3.8 100 ,, 93.7 0-5 3.9 50 Zn 93.4 0.3 3.8 loo I J 94.0 0.7 3.8 From these results it can be seen that, for the quantities given, separation by a single precipitation is satisfactory at least for cobaltn and chromiumm. A further series of experiments on 50-ml.portions of the standard aluminium, solution, with 100mg. of cobalt, chromiumm, nickel or zinc, was carried out with a reprecipitation, i.e., the original benzoate precipitate, after being washed, was dissolved off the paper by hydrochloric acid and the aluminium precipitated a second time, again at a volume of 250-300 ml., under the same conditions as before. The ignited precipitates were not weighed, however, but simply fused with potassium hydrogen sulphate and polarographed as before. In each case the amount of alien metal in the ignited oxide was less than 0.1 mg. Thus a double precipitation is entirely satisfactory for the quantities tried, in all four cases. NOTES- 1. In the polarograph determinations no attempt was made to establish optimum conditions for the accurate determination of each metal concerned.The polarograph was the most convenient means of quickly determining the amount of alien metal present in the residual alumina and the most convenient supporting electrolyte happened to be a potassium hydrogen sulphate solution, which gave waves sufficiently good for the purpose and which were easily reproducible with chromium, nickel or zinc. This medium was not suitable for cobalt however, but neutralisation of the potassium hydrogen sulphate solution by am- monia in the presence of tartaric acid gave suitable conditions for a good reduction wave for cobalt. In each case a saturated calomel electrode was used as anode and waves were obtained at a sensitivity of 1/10. The polarograph used was a Cambridge instrument, and solutions were de-oxygenated by means of a stream of electrolytic hydrogen before the polarograms were taken. 2. The character of the precipitate of aluminium benzoate seems to be particularly important in the separation from chromiumm, e.g., an experiment in which 50 mg. of aluminium were precipitated in presence of 50 and 100 mg. of chromiumm and in which the aluminium benzoate was purposely precipitated as a very flocculent mass by rapid addition of ammonia, gave final alumina containing 1.5 and 2mg. of chromium respectively. SUMMARY Optimum conditions have been fixed for precipitation of aluminium as benzoate. It has been shown that a single precipitation will give a practicable separation of 50mg. of aluminium from quantities of cobaltn and chromiumV1 up to at least 100 mg., but that a double precipitation is desirable for similar mounts of nickeln or zinc. REFERENCES 1. 2. 3. IMPERIAL CHEMICAL INDUSTRIES LTD. Kolthoff, I. M., Stenger, V. A., and Moscovitz, B., J . A m y . Chem. SOC., 1934, 56, 812. Lehrman, L., and Kramer J., Ibid., 2648. Stenger, V. A., Kramer, J., and Beshgetoor, Ind. Eng. Chem., Anal. Ed., 1942, 14, 797. RESEARCH DEPARTMENT October, 1946 BILLINGHAM

ISSN:0003-2654    

DOI:10.1039/AN9477200014

出版商:RSC    

年代:1947

数据来源: RSC

摘要:

426 REVIEWS INKS : THEIR COMPOSITION AND MANUFACTURE. By C. AINSWORTH MITCHELL, D.Sc., F.I.C. Fourth Edition. Pp. xi + 408. London: Charles Grihn tt Co., Ltd. 1937. Price 12s. 6d. net. This, the fourth edition of the standard and, indeed, so far as the reviewer’s knowledge goes, the only text-book on the subject in the language, bridges L gap of 13 years. The author, pre-eminent in his particular sphere, needs little more introduction to the world of technical industry than he does in his official capicity to readers of THE ANALYST, while his reputation in forensic science in all that appertains to handwriting is international. The chemistry of ink, difficult as it is and at times not a little obscure, hcl- riot developed markedly in the interval since 1924; but what progress has been made is covered by Dr.Mitchell in this edition in a very thorough manner. He has found it necessary to enlarge his work to the extent of some 20 per cent. and, in addition, to rewrite a large portion. The arrangement of the book follows the lines of previous editions. After a comprehensive historical introduction, the work is divided into three sections dealing with writing inks, printing inks, and inks for miscellaneous purposes, respectively. Under Section 1 are considered the chemical nature and treatment of the various raw materials used for writing inks from lcmp black to galls, the composition of finished iron-gall, logwood, vanadium, aniline black, and coloured inks, as well as a comprehensive scheme €or the tech~ical examination of inks, handwriting specimens and the identification of forge:-ies.Section 2 deals with the manufacture and examination of printing inks. ,tnd Section 3 with the miscellaneous materials entering into the compositilxx of copying, marking, safety, sympathetic, typewriter inks and so on. Amongst new matter may be noted references to the use of lignone sulphni--,ites in connection with writing ink, a scheme for the identification of individual con- stituents in inks in the form of writing, and the application of filtered ultra-.& if )let light and of infra-red photography in the elucidation of those problems to which such methods are suited. The British Government Standard Specificatior:s for Writing Inks, revised in 1928, are included for the first time. The avaihble evidence upon the constitution of gallotannin is brought up to date and <tbly reviewed, and there is a Comprehensive list of British patents.It is as difficult to withhold admiration of the encyclopaedic scope cjf the matter and references in this book as it is of the erudition and industry displiiyed in its compilation. Practically nothing that comes to mind has escaped atterition, and it is with rather impish glee that the reviewer, after careful search, asserts that he finds no specific reference to the type of alkaline (ammoniacal) gallotannate- iron ink, said t o find favour in the United States, although the di-ammonium hydroxyferrigallate compound of Silbermann and Ozorovitz receives notice. Nor is there mention of that class of quick-drying writing fluids which depend for their efficiency upon partial destruction of the paper sizing by caustic alk 1.5 or sodium silicate.There is no evidence that lignone sulphonate inks have proved se-rious competitors to iron-gall writing inks (pp. 15 and 175). Apart from the unkttmwn quantity of permanence, the principal failing of this type lies in their liability to contain traces of free sulphurous acid to which suspicion attaches in connt-ction426 REVIEWS INKS : THEIR COMPOSITION AND MANUFACTURE. By C. AINSWORTH MITCHELL, D.Sc., F.I.C. Fourth Edition. Pp. xi + 408. London: Charles Grihn tt Co., Ltd. 1937. Price 12s. 6d. net. This, the fourth edition of the standard and, indeed, so far as the reviewer’s knowledge goes, the only text-book on the subject in the language, bridges L gap of 13 years. The author, pre-eminent in his particular sphere, needs little more introduction to the world of technical industry than he does in his official capicity to readers of THE ANALYST, while his reputation in forensic science in all that appertains to handwriting is international.The chemistry of ink, difficult as it is and at times not a little obscure, hcl- riot developed markedly in the interval since 1924; but what progress has been made is covered by Dr. Mitchell in this edition in a very thorough manner. He has found it necessary to enlarge his work to the extent of some 20 per cent. and, in addition, to rewrite a large portion. The arrangement of the book follows the lines of previous editions. After a comprehensive historical introduction, the work is divided into three sections dealing with writing inks, printing inks, and inks for miscellaneous purposes, respectively.Under Section 1 are considered the chemical nature and treatment of the various raw materials used for writing inks from lcmp black to galls, the composition of finished iron-gall, logwood, vanadium, aniline black, and coloured inks, as well as a comprehensive scheme €or the tech~ical examination of inks, handwriting specimens and the identification of forge:-ies. Section 2 deals with the manufacture and examination of printing inks. ,tnd Section 3 with the miscellaneous materials entering into the compositilxx of copying, marking, safety, sympathetic, typewriter inks and so on. Amongst new matter may be noted references to the use of lignone sulphni--,ites in connection with writing ink, a scheme for the identification of individual con- stituents in inks in the form of writing, and the application of filtered ultra-.& if )let light and of infra-red photography in the elucidation of those problems to which such methods are suited.The British Government Standard Specificatior:s for Writing Inks, revised in 1928, are included for the first time. The avaihble evidence upon the constitution of gallotannin is brought up to date and <tbly reviewed, and there is a Comprehensive list of British patents. It is as difficult to withhold admiration of the encyclopaedic scope cjf the matter and references in this book as it is of the erudition and industry displiiyed in its compilation.Practically nothing that comes to mind has escaped atterition, and it is with rather impish glee that the reviewer, after careful search, asserts that he finds no specific reference to the type of alkaline (ammoniacal) gallotannate- iron ink, said t o find favour in the United States, although the di-ammonium hydroxyferrigallate compound of Silbermann and Ozorovitz receives notice. Nor is there mention of that class of quick-drying writing fluids which depend for their efficiency upon partial destruction of the paper sizing by caustic alk 1.5 or sodium silicate. There is no evidence that lignone sulphonate inks have proved se-rious competitors to iron-gall writing inks (pp. 15 and 175). Apart from the unkttmwn quantity of permanence, the principal failing of this type lies in their liability to contain traces of free sulphurous acid to which suspicion attaches in connt-ction426 REVIEWS INKS : THEIR COMPOSITION AND MANUFACTURE.By C. AINSWORTH MITCHELL, D.Sc., F.I.C. Fourth Edition. Pp. xi + 408. London: Charles Grihn tt Co., Ltd. 1937. Price 12s. 6d. net. This, the fourth edition of the standard and, indeed, so far as the reviewer’s knowledge goes, the only text-book on the subject in the language, bridges L gap of 13 years. The author, pre-eminent in his particular sphere, needs little more introduction to the world of technical industry than he does in his official capicity to readers of THE ANALYST, while his reputation in forensic science in all that appertains to handwriting is international. The chemistry of ink, difficult as it is and at times not a little obscure, hcl- riot developed markedly in the interval since 1924; but what progress has been made is covered by Dr.Mitchell in this edition in a very thorough manner. He has found it necessary to enlarge his work to the extent of some 20 per cent. and, in addition, to rewrite a large portion. The arrangement of the book follows the lines of previous editions. After a comprehensive historical introduction, the work is divided into three sections dealing with writing inks, printing inks, and inks for miscellaneous purposes, respectively. Under Section 1 are considered the chemical nature and treatment of the various raw materials used for writing inks from lcmp black to galls, the composition of finished iron-gall, logwood, vanadium, aniline black, and coloured inks, as well as a comprehensive scheme €or the tech~ical examination of inks, handwriting specimens and the identification of forge:-ies.Section 2 deals with the manufacture and examination of printing inks. ,tnd Section 3 with the miscellaneous materials entering into the compositilxx of copying, marking, safety, sympathetic, typewriter inks and so on. Amongst new matter may be noted references to the use of lignone sulphni--,ites in connection with writing ink, a scheme for the identification of individual con- stituents in inks in the form of writing, and the application of filtered ultra-.& if )let light and of infra-red photography in the elucidation of those problems to which such methods are suited. The British Government Standard Specificatior:s for Writing Inks, revised in 1928, are included for the first time.The avaihble evidence upon the constitution of gallotannin is brought up to date and <tbly reviewed, and there is a Comprehensive list of British patents. It is as difficult to withhold admiration of the encyclopaedic scope cjf the matter and references in this book as it is of the erudition and industry displiiyed in its compilation. Practically nothing that comes to mind has escaped atterition, and it is with rather impish glee that the reviewer, after careful search, asserts that he finds no specific reference to the type of alkaline (ammoniacal) gallotannate- iron ink, said t o find favour in the United States, although the di-ammonium hydroxyferrigallate compound of Silbermann and Ozorovitz receives notice.Nor is there mention of that class of quick-drying writing fluids which depend for their efficiency upon partial destruction of the paper sizing by caustic alk 1.5 or sodium silicate. There is no evidence that lignone sulphonate inks have proved se-rious competitors to iron-gall writing inks (pp. 15 and 175). Apart from the unkttmwn quantity of permanence, the principal failing of this type lies in their liability to contain traces of free sulphurous acid to which suspicion attaches in connt-ction426 REVIEWS INKS : THEIR COMPOSITION AND MANUFACTURE. By C. AINSWORTH MITCHELL, D.Sc., F.I.C. Fourth Edition. Pp. xi + 408. London: Charles Grihn tt Co., Ltd. 1937. Price 12s. 6d. net. This, the fourth edition of the standard and, indeed, so far as the reviewer’s knowledge goes, the only text-book on the subject in the language, bridges L gap of 13 years.The author, pre-eminent in his particular sphere, needs little more introduction to the world of technical industry than he does in his official capicity to readers of THE ANALYST, while his reputation in forensic science in all that appertains to handwriting is international. The chemistry of ink, difficult as it is and at times not a little obscure, hcl- riot developed markedly in the interval since 1924; but what progress has been made is covered by Dr. Mitchell in this edition in a very thorough manner. He has found it necessary to enlarge his work to the extent of some 20 per cent. and, in addition, to rewrite a large portion.The arrangement of the book follows the lines of previous editions. After a comprehensive historical introduction, the work is divided into three sections dealing with writing inks, printing inks, and inks for miscellaneous purposes, respectively. Under Section 1 are considered the chemical nature and treatment of the various raw materials used for writing inks from lcmp black to galls, the composition of finished iron-gall, logwood, vanadium, aniline black, and coloured inks, as well as a comprehensive scheme €or the tech~ical examination of inks, handwriting specimens and the identification of forge:-ies. Section 2 deals with the manufacture and examination of printing inks. ,tnd Section 3 with the miscellaneous materials entering into the compositilxx of copying, marking, safety, sympathetic, typewriter inks and so on.Amongst new matter may be noted references to the use of lignone sulphni--,ites in connection with writing ink, a scheme for the identification of individual con- stituents in inks in the form of writing, and the application of filtered ultra-.& if )let light and of infra-red photography in the elucidation of those problems to which such methods are suited. The British Government Standard Specificatior:s for Writing Inks, revised in 1928, are included for the first time. The avaihble evidence upon the constitution of gallotannin is brought up to date and <tbly reviewed, and there is a Comprehensive list of British patents. It is as difficult to withhold admiration of the encyclopaedic scope cjf the matter and references in this book as it is of the erudition and industry displiiyed in its compilation.Practically nothing that comes to mind has escaped atterition, and it is with rather impish glee that the reviewer, after careful search, asserts that he finds no specific reference to the type of alkaline (ammoniacal) gallotannate- iron ink, said t o find favour in the United States, although the di-ammonium hydroxyferrigallate compound of Silbermann and Ozorovitz receives notice. Nor is there mention of that class of quick-drying writing fluids which depend for their efficiency upon partial destruction of the paper sizing by caustic alk 1.5 or sodium silicate. There is no evidence that lignone sulphonate inks have proved se-rious competitors to iron-gall writing inks (pp.15 and 175). Apart from the unkttmwn quantity of permanence, the principal failing of this type lies in their liability to contain traces of free sulphurous acid to which suspicion attaches in connt-ction426 REVIEWS INKS : THEIR COMPOSITION AND MANUFACTURE. By C. AINSWORTH MITCHELL, D.Sc., F.I.C. Fourth Edition. Pp. xi + 408. London: Charles Grihn tt Co., Ltd. 1937. Price 12s. 6d. net. This, the fourth edition of the standard and, indeed, so far as the reviewer’s knowledge goes, the only text-book on the subject in the language, bridges L gap of 13 years. The author, pre-eminent in his particular sphere, needs little more introduction to the world of technical industry than he does in his official capicity to readers of THE ANALYST, while his reputation in forensic science in all that appertains to handwriting is international.The chemistry of ink, difficult as it is and at times not a little obscure, hcl- riot developed markedly in the interval since 1924; but what progress has been made is covered by Dr. Mitchell in this edition in a very thorough manner. He has found it necessary to enlarge his work to the extent of some 20 per cent. and, in addition, to rewrite a large portion. The arrangement of the book follows the lines of previous editions. After a comprehensive historical introduction, the work is divided into three sections dealing with writing inks, printing inks, and inks for miscellaneous purposes, respectively. Under Section 1 are considered the chemical nature and treatment of the various raw materials used for writing inks from lcmp black to galls, the composition of finished iron-gall, logwood, vanadium, aniline black, and coloured inks, as well as a comprehensive scheme €or the tech~ical examination of inks, handwriting specimens and the identification of forge:-ies.Section 2 deals with the manufacture and examination of printing inks. ,tnd Section 3 with the miscellaneous materials entering into the compositilxx of copying, marking, safety, sympathetic, typewriter inks and so on. Amongst new matter may be noted references to the use of lignone sulphni--,ites in connection with writing ink, a scheme for the identification of individual con- stituents in inks in the form of writing, and the application of filtered ultra-.& if )let light and of infra-red photography in the elucidation of those problems to which such methods are suited.The British Government Standard Specificatior:s for Writing Inks, revised in 1928, are included for the first time. The avaihble evidence upon the constitution of gallotannin is brought up to date and <tbly reviewed, and there is a Comprehensive list of British patents. It is as difficult to withhold admiration of the encyclopaedic scope cjf the matter and references in this book as it is of the erudition and industry displiiyed in its compilation. Practically nothing that comes to mind has escaped atterition, and it is with rather impish glee that the reviewer, after careful search, asserts that he finds no specific reference to the type of alkaline (ammoniacal) gallotannate- iron ink, said t o find favour in the United States, although the di-ammonium hydroxyferrigallate compound of Silbermann and Ozorovitz receives notice.Nor is there mention of that class of quick-drying writing fluids which depend for their efficiency upon partial destruction of the paper sizing by caustic alk 1.5 or sodium silicate. There is no evidence that lignone sulphonate inks have proved se-rious competitors to iron-gall writing inks (pp. 15 and 175). Apart from the unkttmwn quantity of permanence, the principal failing of this type lies in their liability to contain traces of free sulphurous acid to which suspicion attaches in connt-ction DAVIES AND KEY: THE DETERMINATION OF COPPER AND ARSENIC IN PYRITES 17 The Determination of Copper and Arsenic in Iron Pyrites by the Method of Internal Electrolysis BY W.CULE DAVIES AND CYRIL KEY THE method commonly used for the determination of copper in iron pyrites1 involves attacking the ore with acid, precipitation of copper sulphide and final deposition of the copper electro- lytically. The method is long, tedious and liable to considerable manipulative error. We have found that the method of internal electrolysis developed by Sand2 and applied to the determination of copper in steel by Fife and Torrance3 can be so modified that the determination of copper in a pyrites is simple, direct, rapid and capable of high accuracy. Some samples of pyrites, the copper content of which had been determined by other methods and other analysts, were examined by the method df internal electrolysis (Table I) with a platinum gauze cathode and the apparatus described by Davies and Key.* Mixtures of concentrated nitric and hydrochloric acids or of nitric and sulphuric acids were used for breaking down the ore.Hydrazine sulphate or hydroxylamine hydrochloride was used to reduce the ferric salt, the much more soluble hydroxylamine salt being preferred because of its superior reducing properties in these solutions. It was found difficult to reduce all the ferric iron in the catholyte by this means, but the residual amount was soon reduced in the electrolysis. Some other reducing agents, e.g., zinc and acid and sodium hypophosphite, precipitate copper; sulphur dioxide is not so satisfactory as the hydrazine or hydroxylamine salt, since when it is used the copper tends to be loosely held on the cathode.METHODS METHOD A. DETERMINATION OF COPPER IN ABSENCE OF ARSENIC- Treat pyrites (3 g., or sufficient to give up to 50 mg. of copper deposit), which has been ground to pass a 100-mesh sieve and dried at 105" C., in a covered dish with 25 to 30 ml. of an acid mixture (70 vols. of concentrated nitric acid with 30 vols. of concentrated sulphuric acid) added in separate small portions. Finally, heat the mixture until copious fuming occurs. Remove insoluble matter by filtration, and treat filtrate and washings (about 300ml.) with ammonia until a slight permanent precipitate appears. Then to the almost boiling solution gradually add 2 to 3 g. of hydroxylamine hydrochloride.Finally, electrolyse at 70" C. for 50 to 75 minutes. Iron rods are used as anodes, with an anolyte of acidified ferrous sulphate solution (containing 5 g. of iron and 3 ml. of concentrated sulphuric acid per 100 ml.) contained in small parchment bags. TABLE I DETERMINATION OF COPPER IN PYRITES Wash the cooled product into a beaker with water and reheat. Some results are given in column 2 of Table I. Copper found, yo I A \ Pyrites sample No. (contains 0.5y0 As) (copper pyrites) BY Method A 1-73 1.71 1-71 1-63 1.62 1-54 1-51 1.55 1.52 1-85 1.83 - - - - BY Method B 1-72 1-72 1-70 1.72 1.58 1.58 1.84 1-86 2-28 1-76 1.765 26-2 By other analysts using other methods- - - 1-70 1.50 1-61 1-55 - 1.90 1.80 - 2-35 2.28 - 1.71 1.64 1-76 - - - - 26- 118 DAVIES AND KEY: THE DETERMINATION OF COPPER AND ARSENIC IN METHOD B.DETERMINATION OF COPPER IN PRESENCE OF ARSENIC- Dissolve the pyrites, neutralise with ammonia, and reduce with hydroxylamine hydro- chloride, as in Method A. Then add a 50 per cent.solution of sodium citrate (40 ml. for about 5 g. of pyrites) and dilute the whole to about 300 ml. If some cuprous oxide is precipitated add enough hydrochloric acid to the hot solution to dissolve this precipitate. This final solution is the catholyte. Prepare the anolyte by adding 20 ml. of the sodium citrate solution to 50 ml. of a ferrous sulphate solution containing the equivalent of 5 g. of iron and 3 ml. of concentrated sulphuric acid per 100 ml. The time required for complete deposition of 50 mg. of copper is 50 minutes.Table I1 gives some results obtained with known mixtures of copper, ferric and arsenic salts. Electrolyse as before at 70" C . Some results for pyrites by Method B are also given in Table I. TABLE I1 DETERMINATION OF COPPER IN MIXTURES OF COPPER, FERRIC AND ARSENIC SALTS Composition of mixture As Fe cu (added as (added as (added as sodium arsenite) ferric alum) copper sulphate) g. g- g. 0.0500 2.0 0.0250 0.1000 3-0 0.0250 0.5000 2.5 0.0250 0.0250 4.0 0-0250 0~1000 4.0 0.0250 0.1000 2-0 0.0500 0-1000 4.0 0.0500 0.5000 3.0 0.0500 0-5000 3.0 0.0300 I A \ cu found g. 0.0250 0.0249 0-0249 0-0250 0.0250 0.0499 0.0500 0-0499 0.0300 TABLE I11 DETERMINATION OF COPPER AND ARSENIC IN SOLUTIONS CONTAIN~NG COPPER SULPHATE, SODIUM ARSENITE AND FERROUS SULPHATE; NO CHLORIDE ION PRESENT Total Total Original Copper added copper and copper and quantity Arsenic during the arsenic arsenic of copper present electrolysis present found g- g.g. g. €5 0.0448 0.010 0-025 0.010 0.045 0-010 0-025 0.020 0.055 0.0551 0-015 0.035 0.025 0.075 0.0749 0.010 0-050 0*010 0.070 0.0698 0.025 0.075 0.020 0.120 0.1202 0.005 0.020 0.010 0.035 0.0352 (b) DETERMINATION OF COPPER AND ARSENIC IN SOLUTIONS CONTAINING COPPER, QUINQUEVALENT ARSENIC AND FERROUS IRON Original quantity of copper g. 0.0250 0-0440 0.0350 0-0500 0.0330 0-0780 0.0590 0.0 Copper found by Method B g. 0.0250 0-0440 0.0349 0-0600 0,0330 0.0782 0.0585 - Arsenic present g. 0.0093 0.0220 0.0080 0-0125 0-0110 0.0310 0.0950 0.00485 Arsenic found g. 0-0092 0.0215 0-0080 0.0124 0.0109 0.03 13 0-0952 0-0048 Iron present as Fe g.2.0 3.0 2.5 2.5 2-5 2.0 2.0 2.0 Extra copper added g. 0.0200 0-0200 0~0100 0~0100 0.0100 0*0200 0.0100 0.0200IRON PYRITES BY THE METHOD OF INTERNAL ELECTROLYSIS 19 (c) DETERMINATION OF COPPER AND ARSENIC IN IRON PYRITES, ETC. Copper found by Sample Method B 1 0-496 2 0.350 3 0-705 4 1-765 5 (pyrites flue dust) 0.01 6 (copper-arsenic 55-6 7 (sulphuric acid) - 8 Ditto - % alloy) (55.5 volumetric) Arsenic found by Method C 0.13 0.12 0.0875. 0.525 0-72 36-2 (36.5 volumetric) 140 parts per lo8 58 Ditto % Arsenic found by Evans's methods 0.12 0.115 0-0875 0.53 0.718 % - 132 parts per lo6 60 parts per 10' METHOD C. DETERMINATION OF ARSENIC IN PYRITES- Make up the pyrites solution to a convenient volume, and take aliquot parts for copper and arsenic determinations.When determining both elements together, add ammonia in the cold until a faint permanent precipitate appears and evaporate the mixture to about 75ml. Reduce ferric iron with hydroxylamine hydrochloride, as described in Method A, add 16 ml. of concentrated hydrochloric acid and 5 g. of sodium hypophosphite, and boil the mixture gently under reflux for 20 minutes. Dilute the solution, transfer to the electrolytic cell, make up to about 300 ml. and electrolyse at 70" C. Add 10 ml. of standard copper solution (1 ml. = 1 mg. Cu) to the catholyte after electrolysis has proceeded for 30 minutes. If necessary, make a further addition of standard copper solution 15 minutes later to complete the deposition of arsenic. The anolyte is a ferrous sulphate solution containing the equivalent of 5g. of iron and 3ml.of concentrated sulphuric acid per 1OOml. When deposition is complete, remove the platinum gauze cathode, wash successively with water, alcohol, and ether, dry at 100" C. and weigh. Deduction of the extra copper added gives the total amount of copper and arsenic originally present; the amount of arsenic is obtained by deducting the copper as detemined by Method B. ARSENIC IN OTHER MATERIALS- To determine arsenic in a solution containing tervalent arsenic and copper, add ferrous sulphate solution equivalent to about 24g. of iron, dilute the mixture to 300ml. and electrolyse at 70" C. To determine arsenic in other materials containing little or no iron, reduce quinquevalent arsenic with sulphurous acid and remove excess of sulphur dioxide by boiling.After the addition of standard copper and ferrous sulphate solutions, electrolyse the mixture in the usual manner. Alternatively, reduce the -arsenic with sodium hypophosphite. To determine arsenic in sulphuric acid, neutralise the acid with ammonia, reduce arsenic with sodium hypophosphite in 15 to 20 per cent. hydrochloric acid solution, add standard copper and ferrous sulphate solutions, and electrolyse in the usual way. Treat flue dusts, from pyrites burners, with nitric acid, and remove excess of nitric acid by adding sulphuric acid and evaporating to fuming. The Whatman diffusion shells used in the determinations to contain the anolyte are slowly attacked by solutions containing hypophosphite and require renewal after one day's continuous use.Where occasional determinations are made, the shells can be preserved for some time, if after being washed they are kept in dilute sulphuric acid. Then proceed as for pyrites. INFLUENCE OF OTHER ELEMENTS- Lead and zinc frequently occur in pyrites. Lead is removed as the insoluble sulphate by the nitric - sulphuric acid mixture used for attacking the ore, but it has no adverse influence, even if present, in the citrate solution of Method B. Zinc, being less noble than iron, is not deposited. Cobalt and nickel sometimes occur in traces in pyrites, but would not be de- posited. Antimony would not normally be removed and if in the tervalent state would be deposited in the acid solution of Method A, but not in the citrate solution of Method B; its occurrence, however, in pyrites is rare, and even then in very small amount.Tin, bismuth and mercury, which Silver, which sometimes occurs in traces, could be removed as chloride.20 DAVIES AND KEY: THE DETERMINATION OF COPPER AND ARSENIC IN might cause difficulties, seldom occur in pyrites : cadmium does not interfere. Table IV gives the results of some determinations of copper in presence of certain other elements. TABLE IV DETERMINATION OF COPPER IN PRESENCE OF OTHER ELEMENTS Copper present g. 0-0250 0.0250 0.0250 0.0400 0-0250 0.0500 0.0400 0-0250 0.0400 Copper found g. 0.0251 0.0250 0.0250 0.0399 0.0251 O.aQ99 0.0400 0.0250 0.0400 Method Other metals present Co, Ni-0.5 g. of each Co, Ni, As-0.5 g. of each Sn-1 g. ; As-0.6 g. Cd-0.1 g .Ditto Ditto cd-0.1 g . PbO-075 g. S b O - 5 g. DISCUSSION The internal electrolysis method described by Fife and TorranceS for the determination of copper in steel, as would be expected, can be applied to the determination of copper in iron pyrites (Method A). In determinations by Method A with certain pyrites, however, the copper deposit on the cathode darkened slightly towards the end of the electrolysis. This was due to simultaneous deposition of arsenic. Provided the arsenic content of the pyrites is not more than 100 parts per million, the error introduced is negligible, for in any event the arsenic is incompletely deposited under these conditions. Many pyrites ores contain appreciable amounts of arsenic, and, therefore, a method of determining copper in them was sought, not involving removal of arsenic by chemical separation.It was established that by carrying out the electrolysis in an almost neutral solution to which excess of sodium citrate had been added, copper was deposited completely and rapidly, without simultaneous deposition of arsenic. Method B, for the determination of copper in presence of arsenic, makes use of this discovery. Since arsenic is deposited with copper on the cathode from a suitable solution, it appeared possible that both elements could be determined together. Solutions containing known amounts of arsenic (as arsenite), ferrous sulphate and copper were electrolysed under the conditions of Method A. The cathode deposit weighed about 16mg. less than theoretical, but contained all the copper originally present.The electrolysis was repeated, but this time a further quantity of a standard copper solution was added after the electrolysis had proceeded for some time. A layer of copper containing the remainder of the arsenic was deposited over the first, dark-coloured, combined deposit of copper and arsenic. The total weight of copper, deducted from the final weight of the combined deposit, gave the weight of arsenic, and this was now equal to the whole quantity originally present. It was found to be important to add a sufficient excess of standard copper solution during the electrolysis to ensure complete deposition of arsenic. The time required for the deposition of 10mg. of arsenic, using a total of 50 mg. of copper, was about 55 minutes at 70" C., the additional 10mg. of copper being added after the electrolysis had proceeded for 30 minutes. If the arsenic was originally present in the quinquevalent state it was necessary first to reduce it to the tervalent state.It was found that sodium hypophosphite in hydrochloric acid was the most satisfactory reducing agent. The solution to be reduced should contain hydrochloric acid equivalent to 15 to 25ml. of the concentrated acid per 100ml. of solution. According to Torrance,6 quantitative electro-deposition of arsenic from a solutionc on- taining it in the tervalent state requires the presence of chloride ion and simultaneous deposi- tion of copper. We now find, however, that, under the conditions we describe for the internal electrolysis method, arsenic is completely deposited with copper even in absence of chloride ion.It should, however, be pointed out that whereas Torrance worked in hydrochloric acid solution of about normal acid concentration, the solutions used in the present methods are almost neutral, so that arsenious acid anions may be present. Such anions may be a possible source of the differences now observed. Table IIT(a) gives a selection of determinations carried out in absence of chloride. ion. Table III(b) gives some determinations in which chloride ion is present, quinquevalent arsenic being reduced by sodium hypophosphite in hydrochloric acid.IRON PYRITES BY THE METHOD OF INTERNAL ELECTROLYSIS 21 It is not possible completely to deposit the arsenic of a pyrites containing carbonaceous matter, although the copper is satisfactorily deposited. Attempts to oxidise the carbonaceous material were not altogether successful, and many of the oxidising agents tried introduced difficulties in the subsequent electrolysis. SUMMARY The internal electrolysis method has been applied to the determination of copper in iron pyrites. For pyrites ore containing appreciable amounts of arsenic, the method is modified to prevent simultaneous deposition of arsenic with copper. It was found that arsenic was not deposited with copper if the electrolysis was conducted in almost neutral solution contain- ing sodium citrate. Details are given for determining arsenic together with copper, by continued electrolysis following further additions of standard copper solution. The influence of possible interfering elements has been studied. REFERENCES 1. Lunge, G., “Technical Chemists’ Handbook,” London, 1010, p. 111. 2. Sand, H. J. S., ANALYST, 1930, 55, 309. 3. Fife, J. G., and Torrance, S., Ibid., 1937, 62, 29. 4. Davies, W. C., and Key, C., Industrial Chemist, 1944,20, 643. 6. Evans, B. S., ANALYST, 1929.54, 623, 1932,57, 492. 6. Torrance, S., Ibid., 1938, 63, 104. CENTRAL RESEARCH DEPARTMENT BROTHERTON & Co., LTD., LEEDS September, 1946

ISSN:0003-2654    

DOI:10.1039/AN9477200017

出版商:RSC    

年代:1947

数据来源: RSC

摘要:

426 REVIEWS INKS : THEIR COMPOSITION AND MANUFACTURE. By C. AINSWORTH MITCHELL, D.Sc., F.I.C. Fourth Edition. Pp. xi + 408. London: Charles Grihn tt Co., Ltd. 1937. Price 12s. 6d. net. This, the fourth edition of the standard and, indeed, so far as the reviewer’s knowledge goes, the only text-book on the subject in the language, bridges L gap of 13 years. The author, pre-eminent in his particular sphere, needs little more introduction to the world of technical industry than he does in his official capicity to readers of THE ANALYST, while his reputation in forensic science in all that appertains to handwriting is international. The chemistry of ink, difficult as it is and at times not a little obscure, hcl- riot developed markedly in the interval since 1924; but what progress has been made is covered by Dr.Mitchell in this edition in a very thorough manner. He has found it necessary to enlarge his work to the extent of some 20 per cent. and, in addition, to rewrite a large portion. The arrangement of the book follows the lines of previous editions. After a comprehensive historical introduction, the work is divided into three sections dealing with writing inks, printing inks, and inks for miscellaneous purposes, respectively. Under Section 1 are considered the chemical nature and treatment of the various raw materials used for writing inks from lcmp black to galls, the composition of finished iron-gall, logwood, vanadium, aniline black, and coloured inks, as well as a comprehensive scheme €or the tech~ical examination of inks, handwriting specimens and the identification of forge:-ies.Section 2 deals with the manufacture and examination of printing inks. ,tnd Section 3 with the miscellaneous materials entering into the compositilxx of copying, marking, safety, sympathetic, typewriter inks and so on. Amongst new matter may be noted references to the use of lignone sulphni--,ites in connection with writing ink, a scheme for the identification of individual con- stituents in inks in the form of writing, and the application of filtered ultra-.& if )let light and of infra-red photography in the elucidation of those problems to which such methods are suited. The British Government Standard Specificatior:s for Writing Inks, revised in 1928, are included for the first time. The avaihble evidence upon the constitution of gallotannin is brought up to date and <tbly reviewed, and there is a Comprehensive list of British patents.It is as difficult to withhold admiration of the encyclopaedic scope cjf the matter and references in this book as it is of the erudition and industry displiiyed in its compilation. Practically nothing that comes to mind has escaped atterition, and it is with rather impish glee that the reviewer, after careful search, asserts that he finds no specific reference to the type of alkaline (ammoniacal) gallotannate- iron ink, said t o find favour in the United States, although the di-ammonium hydroxyferrigallate compound of Silbermann and Ozorovitz receives notice. Nor is there mention of that class of quick-drying writing fluids which depend for their efficiency upon partial destruction of the paper sizing by caustic alk 1.5 or sodium silicate.There is no evidence that lignone sulphonate inks have proved se-rious competitors to iron-gall writing inks (pp. 15 and 175). Apart from the unkttmwn quantity of permanence, the principal failing of this type lies in their liability to contain traces of free sulphurous acid to which suspicion attaches in connt-ction426 REVIEWS INKS : THEIR COMPOSITION AND MANUFACTURE. By C. AINSWORTH MITCHELL, D.Sc., F.I.C. Fourth Edition. Pp. xi + 408. London: Charles Grihn tt Co., Ltd. 1937. Price 12s. 6d. net. This, the fourth edition of the standard and, indeed, so far as the reviewer’s knowledge goes, the only text-book on the subject in the language, bridges L gap of 13 years. The author, pre-eminent in his particular sphere, needs little more introduction to the world of technical industry than he does in his official capicity to readers of THE ANALYST, while his reputation in forensic science in all that appertains to handwriting is international.The chemistry of ink, difficult as it is and at times not a little obscure, hcl- riot developed markedly in the interval since 1924; but what progress has been made is covered by Dr. Mitchell in this edition in a very thorough manner. He has found it necessary to enlarge his work to the extent of some 20 per cent. and, in addition, to rewrite a large portion. The arrangement of the book follows the lines of previous editions. After a comprehensive historical introduction, the work is divided into three sections dealing with writing inks, printing inks, and inks for miscellaneous purposes, respectively.Under Section 1 are considered the chemical nature and treatment of the various raw materials used for writing inks from lcmp black to galls, the composition of finished iron-gall, logwood, vanadium, aniline black, and coloured inks, as well as a comprehensive scheme €or the tech~ical examination of inks, handwriting specimens and the identification of forge:-ies. Section 2 deals with the manufacture and examination of printing inks. ,tnd Section 3 with the miscellaneous materials entering into the compositilxx of copying, marking, safety, sympathetic, typewriter inks and so on. Amongst new matter may be noted references to the use of lignone sulphni--,ites in connection with writing ink, a scheme for the identification of individual con- stituents in inks in the form of writing, and the application of filtered ultra-.& if )let light and of infra-red photography in the elucidation of those problems to which such methods are suited.The British Government Standard Specificatior:s for Writing Inks, revised in 1928, are included for the first time. The avaihble evidence upon the constitution of gallotannin is brought up to date and <tbly reviewed, and there is a Comprehensive list of British patents. It is as difficult to withhold admiration of the encyclopaedic scope cjf the matter and references in this book as it is of the erudition and industry displiiyed in its compilation.Practically nothing that comes to mind has escaped atterition, and it is with rather impish glee that the reviewer, after careful search, asserts that he finds no specific reference to the type of alkaline (ammoniacal) gallotannate- iron ink, said t o find favour in the United States, although the di-ammonium hydroxyferrigallate compound of Silbermann and Ozorovitz receives notice. Nor is there mention of that class of quick-drying writing fluids which depend for their efficiency upon partial destruction of the paper sizing by caustic alk 1.5 or sodium silicate. There is no evidence that lignone sulphonate inks have proved se-rious competitors to iron-gall writing inks (pp. 15 and 175). Apart from the unkttmwn quantity of permanence, the principal failing of this type lies in their liability to contain traces of free sulphurous acid to which suspicion attaches in connt-ction IRON PYRITES BY THE METHOD OF INTERNAL ELECTROLYSIS 21 Notes A NOTE ON ALCOHOL IN BLOOD AND URINE DURING the past ten years this Laboratory has often been called upon to determine the alcohol in sarnples*of blood and urine and we have used the Widmark method.From the first it was noticed that the urine figures were invariably higher than thdse for the blood and that the discrepancy was more pronounced if the samples had been kept overnight before the analysis. In a case where death occurred one morning, a post-mortem examination was carried out in the afternoon, and the blood and urine were analysed for alcohol the following morning. The urine was found to contain 0-37 per cent.of alcohol, whereas the blood contained only 0.22 per cent. Experiments were carried out and it was found that the concentration of alcohol in blood decreased rapidly on keeping, especially if the samples were not stored in the refrigerator. In one typical case, in 24 hours, even though the sample was stored in the refrigerator, the concentration dropped from 0-09 per cent. to 0.06 per cent. On the other hand, refrigerator-stored urines were constant for long periods. Three uMes, with alcohol contents of 0-14, 0.30 and 0.24 per cent., had the same values after one month’s keeping, and one of 0-34 per cent. was unchanged after two months’ storage. It is now the practice of the Laboratory to regard the urine figures as the more reliable, especially if any time elapses between the taking of the sample and the analysis.DOMINION LABORATORY DEPARTMENT OF SCIENTIFIC AND INDUSTRIAL RESEARCH WELLINGTON, NEW ZEALAND R. L. ANDREW L. G. NEUBAUER September, 1946 THE DISTRIBUTION OF BARBITURATES IN THE HUMAN BODY DURING the past twenty years we have examined many exhibits for barbiturates, mostly in cases of suicide. During 1936 in a case (A) where sodium barbitone (medinal) equivalent to 225 grains of barbitone (veronal) had been taken by the deceased a wide range of organs was submitted for examination. The amounts found in the various organs were approximately the same, and the muscle tissue contained a similar amount. It could therefore be concluded that the barbitone was uniformly distributed throughout the body.The results from cases B, C , D and E confirm this. It will be seen that there is no concentration in the liver or in the brain, although in “ Toxicology ” by McNally, p. 721 , there is a reference to a fatal case of poisoning by pheno- barbitone (Wright, Arch. Int. Med., 1929, 43, 85) in which the concentration of the drug is22 ABSTRACTS OF CHEMICAL PAPERS given as 90mg. per 100 grams in the brain, but as only 3 and 5 milligrams in the stomach and liver respectively. Our figures show that there is no concentration in the brain and we are of the opinion that the figures given by McNally are erroneous. The figures obtained by us indicate that the approximate amount of barbiturate in the body can be calculated from the proportion found in any one organ. The following table gives the results obtained from five typical cases: CONCENTRATION, MILLIGRAMS PER 100 GRAMS Cerebro- Intes- Thigh spinal Case found Liver Brain Kidney Stomach contents Lung tine muscle Urine fluid A. Barbitone . . 13 16 14 12 - 12 14 11 37 - B. Phenobarbitone 6 6 - - - - - - - - C. Barbitone . . 9 13 9 8 8 D. ,, .. 20 20 24 - 277 - - 21 - I S 27 24 E. .. 28 - 28 29 Barbiturate Stomach - - - - - - - - - - In Case D the high concentration in the stomach contents was due to the presence of a large quantity of undissolved drug, death having occurred fairly rapidly after the taking of the drug. The white lumps could be easily picked out and washed and identified. It will be seen that the figure for urine in Case E corresponds to that in the organs examined but in Case A the figure for urine is much higher than the figures for the organs. We can offer no explanation for this difference. DOMINION LABORATORY L. G. NEUBAUER R. L. ANDREW DEPARTMENT OF SCIENTIFIC AND INDUSTRIAL RESEARCH September, 1946 WELLINGTON, NEW ZEALAND '

ISSN:0003-2654    

DOI:10.1039/AN9477200021

出版商:RSC    

年代:1947

数据来源: RSC

摘要:

426 REVIEWS INKS : THEIR COMPOSITION AND MANUFACTURE. By C. AINSWORTH MITCHELL, D.Sc., F.I.C. Fourth Edition. Pp. xi + 408. London: Charles Grihn tt Co., Ltd. 1937. Price 12s. 6d. net. This, the fourth edition of the standard and, indeed, so far as the reviewer’s knowledge goes, the only text-book on the subject in the language, bridges L gap of 13 years. The author, pre-eminent in his particular sphere, needs little more introduction to the world of technical industry than he does in his official capicity to readers of THE ANALYST, while his reputation in forensic science in all that appertains to handwriting is international. The chemistry of ink, difficult as it is and at times not a little obscure, hcl- riot developed markedly in the interval since 1924; but what progress has been made is covered by Dr.Mitchell in this edition in a very thorough manner. He has found it necessary to enlarge his work to the extent of some 20 per cent. and, in addition, to rewrite a large portion. The arrangement of the book follows the lines of previous editions. After a comprehensive historical introduction, the work is divided into three sections dealing with writing inks, printing inks, and inks for miscellaneous purposes, respectively. Under Section 1 are considered the chemical nature and treatment of the various raw materials used for writing inks from lcmp black to galls, the composition of finished iron-gall, logwood, vanadium, aniline black, and coloured inks, as well as a comprehensive scheme €or the tech~ical examination of inks, handwriting specimens and the identification of forge:-ies.Section 2 deals with the manufacture and examination of printing inks. ,tnd Section 3 with the miscellaneous materials entering into the compositilxx of copying, marking, safety, sympathetic, typewriter inks and so on. Amongst new matter may be noted references to the use of lignone sulphni--,ites in connection with writing ink, a scheme for the identification of individual con- stituents in inks in the form of writing, and the application of filtered ultra-.& if )let light and of infra-red photography in the elucidation of those problems to which such methods are suited. The British Government Standard Specificatior:s for Writing Inks, revised in 1928, are included for the first time. The avaihble evidence upon the constitution of gallotannin is brought up to date and <tbly reviewed, and there is a Comprehensive list of British patents.It is as difficult to withhold admiration of the encyclopaedic scope cjf the matter and references in this book as it is of the erudition and industry displiiyed in its compilation. Practically nothing that comes to mind has escaped atterition, and it is with rather impish glee that the reviewer, after careful search, asserts that he finds no specific reference to the type of alkaline (ammoniacal) gallotannate- iron ink, said t o find favour in the United States, although the di-ammonium hydroxyferrigallate compound of Silbermann and Ozorovitz receives notice. Nor is there mention of that class of quick-drying writing fluids which depend for their efficiency upon partial destruction of the paper sizing by caustic alk 1.5 or sodium silicate.There is no evidence that lignone sulphonate inks have proved se-rious competitors to iron-gall writing inks (pp. 15 and 175). Apart from the unkttmwn quantity of permanence, the principal failing of this type lies in their liability to contain traces of free sulphurous acid to which suspicion attaches in connt-ction426 REVIEWS INKS : THEIR COMPOSITION AND MANUFACTURE. By C. AINSWORTH MITCHELL, D.Sc., F.I.C. Fourth Edition. Pp. xi + 408. London: Charles Grihn tt Co., Ltd. 1937. Price 12s. 6d. net. This, the fourth edition of the standard and, indeed, so far as the reviewer’s knowledge goes, the only text-book on the subject in the language, bridges L gap of 13 years. The author, pre-eminent in his particular sphere, needs little more introduction to the world of technical industry than he does in his official capicity to readers of THE ANALYST, while his reputation in forensic science in all that appertains to handwriting is international.The chemistry of ink, difficult as it is and at times not a little obscure, hcl- riot developed markedly in the interval since 1924; but what progress has been made is covered by Dr. Mitchell in this edition in a very thorough manner. He has found it necessary to enlarge his work to the extent of some 20 per cent. and, in addition, to rewrite a large portion. The arrangement of the book follows the lines of previous editions. After a comprehensive historical introduction, the work is divided into three sections dealing with writing inks, printing inks, and inks for miscellaneous purposes, respectively.Under Section 1 are considered the chemical nature and treatment of the various raw materials used for writing inks from lcmp black to galls, the composition of finished iron-gall, logwood, vanadium, aniline black, and coloured inks, as well as a comprehensive scheme €or the tech~ical examination of inks, handwriting specimens and the identification of forge:-ies. Section 2 deals with the manufacture and examination of printing inks. ,tnd Section 3 with the miscellaneous materials entering into the compositilxx of copying, marking, safety, sympathetic, typewriter inks and so on. Amongst new matter may be noted references to the use of lignone sulphni--,ites in connection with writing ink, a scheme for the identification of individual con- stituents in inks in the form of writing, and the application of filtered ultra-.& if )let light and of infra-red photography in the elucidation of those problems to which such methods are suited.The British Government Standard Specificatior:s for Writing Inks, revised in 1928, are included for the first time. The avaihble evidence upon the constitution of gallotannin is brought up to date and <tbly reviewed, and there is a Comprehensive list of British patents. It is as difficult to withhold admiration of the encyclopaedic scope cjf the matter and references in this book as it is of the erudition and industry displiiyed in its compilation.Practically nothing that comes to mind has escaped atterition, and it is with rather impish glee that the reviewer, after careful search, asserts that he finds no specific reference to the type of alkaline (ammoniacal) gallotannate- iron ink, said t o find favour in the United States, although the di-ammonium hydroxyferrigallate compound of Silbermann and Ozorovitz receives notice. Nor is there mention of that class of quick-drying writing fluids which depend for their efficiency upon partial destruction of the paper sizing by caustic alk 1.5 or sodium silicate. There is no evidence that lignone sulphonate inks have proved se-rious competitors to iron-gall writing inks (pp. 15 and 175). Apart from the unkttmwn quantity of permanence, the principal failing of this type lies in their liability to contain traces of free sulphurous acid to which suspicion attaches in connt-ction 22 ABSTRACTS OF CHEMICAL PAPERS ABSTRACTS OF PAPERS PUBLISHED IN OTHER JOURNALS Food and Drugs South African Fish Products.Part XXII. Periodic Acid as Reagent in the Analysis of the Unsaponifiable Fraction of Natural Fats. M. L. Karnovsky and W. S . Rapson ( J . SOC. Chem. Ind., 1946,65, 138--140)-Since the a-glyceryl ethers are the only 1 : 2-glycols recorded as com- ponents of unsaponifiable fractions of natural fats, their estimation by means of such reagents as lead tetra-acetate or periodic acid, which act specifically on 1 : 2-glycols, has been explored. Both these reagents effect the oxidation of a-glyceryl ethers according to the scheme CH,OR.CHOH.CH,OH -+ CH,OR.CHO + CH,O and the course of the reaction has been followed by estimation both of the reagent consumed and of the formaldehyde generated.The use of lead tetra-acetate was abandoned because it attacked other constituents of the unsaponifiable matter, especially squalene. Periodic acid, applied first in acetic acid and later in ethyl alcohol and ethyl acetate solutions, proved to be a more selective reagent. It was considered desirable that the method of estimating a-glyceryl ethers should be a direct sequel to the ordinary S.P.A. method for determining unsaponifiable matter, using 2 g. of fat (or more when necessary), and should be applic- able to the very small amounts of material often obtained in that method. Consequently, conditions were determined for the use of 0.0325 N periodic acid, and, under these conditions, the oxidation of batyl alcohol was found to be complete in 4 hr.Acetic acid was not used in the final procedure owing to the difficulty of adjusting the PH of the reaction mixture in its presence in the subsequent method for estimating the excess of oxidising agent with sodium arsenite. Under the conditions finally selected, the sample of batyl alcohol available assayed a t 98.13 per cent. pure on the basis of reagent consumed, and at 99-9 per cent. on the basis of formaldehyde generated in the reaction. Samples of unsaponifiable matter were prepared by dissolving them in either ethyl alcohol or ethyl acetate, or in mixtures of both, there being no interference by either of these solvents.Procedure-To prepare the periodic acid reagent, dissolve 2.4 g. of sodium paraperiodate in 15 ml. of water containing 0.8 ml. of sulphuric acid, and add 235 ml. of 96 per cent. alcohol, purified, if necessary, by distillation from potassium hydroxide in presence of aluminium turnings. Remove the white pre- cipitate by filtration, and allow the reagent to stand overnight. The standard sodium arsenite solution is about 0.02 N, and contains 10 g. of sodium bicarbonate per litre, and is adjusted to give a back-titration figure of 3 to 5 ml. of 0.02 I\I iodine for 5 ml. of periodic acid in a blank determination. It is useful to know, in each batch of solutions, the direct titre of the standard iodine solution used (0.02 N) against the sodium arsenite solution so that, in any experiment, it is immediately evident that the necessary excess of periodic acid has been added.Isolate the unsaponifiable matter by the method of the S.P.A. (ANALYST, 1933, 58, 203): but with four ether extractions instead of three. To 5 ml. of a solution of 35 to 50mg. of unsaponifiable matter in 5 ml. of alcohol or ethyl acetate in a conical flask, add 5 ml. of periodic acid reagent, and swirl the mixture at 10-min. intervals for the first half-hour and, subsequently, a t half-hourly intervals. If the a-glyceryl content is high, a white precipitate of iodic acid separates within 10 min. At the end of four hours, add 25ml. of saturated sodium bicarbonate solution, measuredBIOCHEMICAL 23 from a cylinder, and 25 ml. of the standard sodium arsenite solution from a pipette.Organic matter will be precipitated (this is less evident when ethyl acetate is the solvent) and the iodic acid will dissolve, Add 3 ml. of 10 per cent. potassium iodide solution, swirl the mixture thoroughly, allow it to stand for 15 min., rinse down the sides of the flask with about 15 ml. of water, and titrate the excess of sodium arsenite with 0.02 N iodine, starch being used as indicator. Carry out blank determinations simultaneously, 5 ml. of the solvent instead of the sample solution being used. From the result of the titration, calculate the percentage of a-glyceryl ether as selachyl alcohol (50 mg. of selachyl alcohol 5 0.146 mg.-mol.). To determine the formaldehyde generated in the reaction, add to the oxidation mixture that has been ailowed to stand for 4 hr.(supra-) 30ml. of water, 9 ml. of N hydrochloric acid, and 3 ml. of sodium arsenite. Mix thoroughly, and when the colour formed has disappeared, add 60 ml. of a buffer solution made by mixing 1 volume of 1.7 N hydrochloric acid with 2 volumes of 1.7 N sodium acetate, and filter through a pad of filter-aid, gentle suction being used. pad with another 20 ml. of buffer solution, and then with about 10ml. of water from 3 wash- To the clear filtrate (pH 4.6), add 2 ml. of 5 per cent, alcoholic -dimedone solution, shake the mixture thoroughly, and allow it to stand for 18 hr. Collect the precipitate in a tared, sintered glass crucible, wash it with distilled water, dry the crucible a t 85" C. for 20 min., and weigh. A blank determination may be made with the reagents, but this has never been found to be positive.The method is regarded as giving results to an accuracy not greater than 1.5 per cent. Where the a-glyceryl ether content is low, i t is always advisable to use 5-ml. aliquots containing more than 50mg. of unssponifiable matter, and, owing to its greater solvent power, ethyl acetate is then the better solvent. The use of aliquots greater than 5 ml. introduces difficulties in adjusting the conditions. With many fats, as with batyl alcohol itself, agreement was found between the results of the two methods. Discrepancies with a iiumber of fats indicate, however, the existence in their unsaponifiable fractions of substances other than a-glyceryl ethers that are attacked by periodic acid, and these instances are under fuller investiga- tion.A. 0. J. Assay for Choline Chloride in Pharma- ceutical Products. W. C. Gakenheimer and R. M. Regnera (1. Amer. Pharm. Assoc., 1946, 35, 311-312)-The recent interest in the oral administration of choline for the treatment of certain diseases of the liver has led to the need for an accurate assay of choline chloride in pharma- ceutical products. The use of phosphotungstic acid as a precipitant has been found to be rapid and reliable. Melhod-(a) For liquid samples (solutions in water, elixirs, syrups, etc.)-Transfer such a volume of the sample as may be expected to contain about 1 g. of choline chloride to a 100-ml. volumetric flask and heat on a steam bath a t a reduced pressure (100-125 mm. of Hg) to drive off moisture and any interfering decomposition products, such as ethyl- amine, that may be present.While the residue is still warm, shake i t with 80 ml. of absolute alcohol, COOL and dilute to 100ml. with the same solvent. Allow to settle, transfer 5 ml, of the clear super- iiatant liquid to a beaker containing 10ml. of a Wash the flask and, ' bottle. filtered, 10 per cent, solution of phosphotungstic acid in absolute alcohol, digest the mixture on a steam bath for 5 min., and filter through a tared, sintered glass crucible of fine porosity. Wash the residue on the filter with 6 ml. of absolute alcohol, dry a t 55O C. for 2 hr., and weigh. Multiply the weight of the precipitate by the factor 0.1375 to convert to choline chloride. (b) For solid samples (tablets, capsules, etc.)- Extract an accurately weighed portion of the sample, expected to contain about 0-6 g. of choline chloride, in a micro-Soxhlet apparatus with 20 ml. of absolute alcohol for 3 hr. Transfer the extract quantita- tively to a 50-ml. volumetric flask, distil off the alcohol, and heat the residue a t 100°C. under reduced pressure for 15 min. as before. Dissolve in absolute alcohol, dilute to 50ml. with the same solvent, and continue the assay as described above. The factor given for converting the weight of precipitate to that of choline chloride is higher than the theoretical one of 0.1291 to compensate for the slight soliibility of choline phosphatungstate in absolute alcohol under the assay conditions de- scribed. Different batches of phosphotungstic acid have been examined under the same conditions: the maximum variation in the weights of precipitate obtained was 0.7 per cent. and, although absolute alcohol was used in the experiments, i t is stated that anhydrous denatured alcohol is satisfactory. No interfering substances have been encountered in several common vehicles tested. Results cited indicate that a satisfactory recovery of choline chloride is obtained when typical pharmaceutical products are submitted to the assay procedure. J. A.

ISSN:0003-2654    

DOI:10.1039/AN9477200022

出版商:RSC    

年代:1947

数据来源: RSC

摘要:

426 REVIEWS INKS : THEIR COMPOSITION AND MANUFACTURE. By C. AINSWORTH MITCHELL, D.Sc., F.I.C. Fourth Edition. Pp. xi + 408. London: Charles Grihn tt Co., Ltd. 1937. Price 12s. 6d. net. This, the fourth edition of the standard and, indeed, so far as the reviewer’s knowledge goes, the only text-book on the subject in the language, bridges L gap of 13 years. The author, pre-eminent in his particular sphere, needs little more introduction to the world of technical industry than he does in his official capicity to readers of THE ANALYST, while his reputation in forensic science in all that appertains to handwriting is international. The chemistry of ink, difficult as it is and at times not a little obscure, hcl- riot developed markedly in the interval since 1924; but what progress has been made is covered by Dr.Mitchell in this edition in a very thorough manner. He has found it necessary to enlarge his work to the extent of some 20 per cent. and, in addition, to rewrite a large portion. The arrangement of the book follows the lines of previous editions. After a comprehensive historical introduction, the work is divided into three sections dealing with writing inks, printing inks, and inks for miscellaneous purposes, respectively. Under Section 1 are considered the chemical nature and treatment of the various raw materials used for writing inks from lcmp black to galls, the composition of finished iron-gall, logwood, vanadium, aniline black, and coloured inks, as well as a comprehensive scheme €or the tech~ical examination of inks, handwriting specimens and the identification of forge:-ies.Section 2 deals with the manufacture and examination of printing inks. ,tnd Section 3 with the miscellaneous materials entering into the compositilxx of copying, marking, safety, sympathetic, typewriter inks and so on. Amongst new matter may be noted references to the use of lignone sulphni--,ites in connection with writing ink, a scheme for the identification of individual con- stituents in inks in the form of writing, and the application of filtered ultra-.& if )let light and of infra-red photography in the elucidation of those problems to which such methods are suited. The British Government Standard Specificatior:s for Writing Inks, revised in 1928, are included for the first time. The avaihble evidence upon the constitution of gallotannin is brought up to date and <tbly reviewed, and there is a Comprehensive list of British patents.It is as difficult to withhold admiration of the encyclopaedic scope cjf the matter and references in this book as it is of the erudition and industry displiiyed in its compilation. Practically nothing that comes to mind has escaped atterition, and it is with rather impish glee that the reviewer, after careful search, asserts that he finds no specific reference to the type of alkaline (ammoniacal) gallotannate- iron ink, said t o find favour in the United States, although the di-ammonium hydroxyferrigallate compound of Silbermann and Ozorovitz receives notice. Nor is there mention of that class of quick-drying writing fluids which depend for their efficiency upon partial destruction of the paper sizing by caustic alk 1.5 or sodium silicate.There is no evidence that lignone sulphonate inks have proved se-rious competitors to iron-gall writing inks (pp. 15 and 175). Apart from the unkttmwn quantity of permanence, the principal failing of this type lies in their liability to contain traces of free sulphurous acid to which suspicion attaches in connt-ction426 REVIEWS INKS : THEIR COMPOSITION AND MANUFACTURE. By C. AINSWORTH MITCHELL, D.Sc., F.I.C. Fourth Edition. Pp. xi + 408. London: Charles Grihn tt Co., Ltd. 1937. Price 12s. 6d. net. This, the fourth edition of the standard and, indeed, so far as the reviewer’s knowledge goes, the only text-book on the subject in the language, bridges L gap of 13 years. The author, pre-eminent in his particular sphere, needs little more introduction to the world of technical industry than he does in his official capicity to readers of THE ANALYST, while his reputation in forensic science in all that appertains to handwriting is international.The chemistry of ink, difficult as it is and at times not a little obscure, hcl- riot developed markedly in the interval since 1924; but what progress has been made is covered by Dr. Mitchell in this edition in a very thorough manner. He has found it necessary to enlarge his work to the extent of some 20 per cent. and, in addition, to rewrite a large portion. The arrangement of the book follows the lines of previous editions. After a comprehensive historical introduction, the work is divided into three sections dealing with writing inks, printing inks, and inks for miscellaneous purposes, respectively.Under Section 1 are considered the chemical nature and treatment of the various raw materials used for writing inks from lcmp black to galls, the composition of finished iron-gall, logwood, vanadium, aniline black, and coloured inks, as well as a comprehensive scheme €or the tech~ical examination of inks, handwriting specimens and the identification of forge:-ies. Section 2 deals with the manufacture and examination of printing inks. ,tnd Section 3 with the miscellaneous materials entering into the compositilxx of copying, marking, safety, sympathetic, typewriter inks and so on. Amongst new matter may be noted references to the use of lignone sulphni--,ites in connection with writing ink, a scheme for the identification of individual con- stituents in inks in the form of writing, and the application of filtered ultra-.& if )let light and of infra-red photography in the elucidation of those problems to which such methods are suited.The British Government Standard Specificatior:s for Writing Inks, revised in 1928, are included for the first time. The avaihble evidence upon the constitution of gallotannin is brought up to date and <tbly reviewed, and there is a Comprehensive list of British patents. It is as difficult to withhold admiration of the encyclopaedic scope cjf the matter and references in this book as it is of the erudition and industry displiiyed in its compilation.Practically nothing that comes to mind has escaped atterition, and it is with rather impish glee that the reviewer, after careful search, asserts that he finds no specific reference to the type of alkaline (ammoniacal) gallotannate- iron ink, said t o find favour in the United States, although the di-ammonium hydroxyferrigallate compound of Silbermann and Ozorovitz receives notice. Nor is there mention of that class of quick-drying writing fluids which depend for their efficiency upon partial destruction of the paper sizing by caustic alk 1.5 or sodium silicate. There is no evidence that lignone sulphonate inks have proved se-rious competitors to iron-gall writing inks (pp. 15 and 175). Apart from the unkttmwn quantity of permanence, the principal failing of this type lies in their liability to contain traces of free sulphurous acid to which suspicion attaches in connt-ction426 REVIEWS INKS : THEIR COMPOSITION AND MANUFACTURE.By C. AINSWORTH MITCHELL, D.Sc., F.I.C. Fourth Edition. Pp. xi + 408. London: Charles Grihn tt Co., Ltd. 1937. Price 12s. 6d. net. This, the fourth edition of the standard and, indeed, so far as the reviewer’s knowledge goes, the only text-book on the subject in the language, bridges L gap of 13 years. The author, pre-eminent in his particular sphere, needs little more introduction to the world of technical industry than he does in his official capicity to readers of THE ANALYST, while his reputation in forensic science in all that appertains to handwriting is international. The chemistry of ink, difficult as it is and at times not a little obscure, hcl- riot developed markedly in the interval since 1924; but what progress has been made is covered by Dr.Mitchell in this edition in a very thorough manner. He has found it necessary to enlarge his work to the extent of some 20 per cent. and, in addition, to rewrite a large portion. The arrangement of the book follows the lines of previous editions. After a comprehensive historical introduction, the work is divided into three sections dealing with writing inks, printing inks, and inks for miscellaneous purposes, respectively. Under Section 1 are considered the chemical nature and treatment of the various raw materials used for writing inks from lcmp black to galls, the composition of finished iron-gall, logwood, vanadium, aniline black, and coloured inks, as well as a comprehensive scheme €or the tech~ical examination of inks, handwriting specimens and the identification of forge:-ies.Section 2 deals with the manufacture and examination of printing inks. ,tnd Section 3 with the miscellaneous materials entering into the compositilxx of copying, marking, safety, sympathetic, typewriter inks and so on. Amongst new matter may be noted references to the use of lignone sulphni--,ites in connection with writing ink, a scheme for the identification of individual con- stituents in inks in the form of writing, and the application of filtered ultra-.& if )let light and of infra-red photography in the elucidation of those problems to which such methods are suited. The British Government Standard Specificatior:s for Writing Inks, revised in 1928, are included for the first time.The avaihble evidence upon the constitution of gallotannin is brought up to date and <tbly reviewed, and there is a Comprehensive list of British patents. It is as difficult to withhold admiration of the encyclopaedic scope cjf the matter and references in this book as it is of the erudition and industry displiiyed in its compilation. Practically nothing that comes to mind has escaped atterition, and it is with rather impish glee that the reviewer, after careful search, asserts that he finds no specific reference to the type of alkaline (ammoniacal) gallotannate- iron ink, said t o find favour in the United States, although the di-ammonium hydroxyferrigallate compound of Silbermann and Ozorovitz receives notice.Nor is there mention of that class of quick-drying writing fluids which depend for their efficiency upon partial destruction of the paper sizing by caustic alk 1.5 or sodium silicate. There is no evidence that lignone sulphonate inks have proved se-rious competitors to iron-gall writing inks (pp. 15 and 175). Apart from the unkttmwn quantity of permanence, the principal failing of this type lies in their liability to contain traces of free sulphurous acid to which suspicion attaches in connt-ction426 REVIEWS INKS : THEIR COMPOSITION AND MANUFACTURE. By C. AINSWORTH MITCHELL, D.Sc., F.I.C. Fourth Edition. Pp. xi + 408. London: Charles Grihn tt Co., Ltd. 1937. Price 12s. 6d. net. This, the fourth edition of the standard and, indeed, so far as the reviewer’s knowledge goes, the only text-book on the subject in the language, bridges L gap of 13 years.The author, pre-eminent in his particular sphere, needs little more introduction to the world of technical industry than he does in his official capicity to readers of THE ANALYST, while his reputation in forensic science in all that appertains to handwriting is international. The chemistry of ink, difficult as it is and at times not a little obscure, hcl- riot developed markedly in the interval since 1924; but what progress has been made is covered by Dr. Mitchell in this edition in a very thorough manner. He has found it necessary to enlarge his work to the extent of some 20 per cent. and, in addition, to rewrite a large portion.The arrangement of the book follows the lines of previous editions. After a comprehensive historical introduction, the work is divided into three sections dealing with writing inks, printing inks, and inks for miscellaneous purposes, respectively. Under Section 1 are considered the chemical nature and treatment of the various raw materials used for writing inks from lcmp black to galls, the composition of finished iron-gall, logwood, vanadium, aniline black, and coloured inks, as well as a comprehensive scheme €or the tech~ical examination of inks, handwriting specimens and the identification of forge:-ies. Section 2 deals with the manufacture and examination of printing inks. ,tnd Section 3 with the miscellaneous materials entering into the compositilxx of copying, marking, safety, sympathetic, typewriter inks and so on.Amongst new matter may be noted references to the use of lignone sulphni--,ites in connection with writing ink, a scheme for the identification of individual con- stituents in inks in the form of writing, and the application of filtered ultra-.& if )let light and of infra-red photography in the elucidation of those problems to which such methods are suited. The British Government Standard Specificatior:s for Writing Inks, revised in 1928, are included for the first time. The avaihble evidence upon the constitution of gallotannin is brought up to date and <tbly reviewed, and there is a Comprehensive list of British patents. It is as difficult to withhold admiration of the encyclopaedic scope cjf the matter and references in this book as it is of the erudition and industry displiiyed in its compilation.Practically nothing that comes to mind has escaped atterition, and it is with rather impish glee that the reviewer, after careful search, asserts that he finds no specific reference to the type of alkaline (ammoniacal) gallotannate- iron ink, said t o find favour in the United States, although the di-ammonium hydroxyferrigallate compound of Silbermann and Ozorovitz receives notice. Nor is there mention of that class of quick-drying writing fluids which depend for their efficiency upon partial destruction of the paper sizing by caustic alk 1.5 or sodium silicate. There is no evidence that lignone sulphonate inks have proved se-rious competitors to iron-gall writing inks (pp.15 and 175). Apart from the unkttmwn quantity of permanence, the principal failing of this type lies in their liability to contain traces of free sulphurous acid to which suspicion attaches in connt-ction426 REVIEWS INKS : THEIR COMPOSITION AND MANUFACTURE. By C. AINSWORTH MITCHELL, D.Sc., F.I.C. Fourth Edition. Pp. xi + 408. London: Charles Grihn tt Co., Ltd. 1937. Price 12s. 6d. net. This, the fourth edition of the standard and, indeed, so far as the reviewer’s knowledge goes, the only text-book on the subject in the language, bridges L gap of 13 years. The author, pre-eminent in his particular sphere, needs little more introduction to the world of technical industry than he does in his official capicity to readers of THE ANALYST, while his reputation in forensic science in all that appertains to handwriting is international.The chemistry of ink, difficult as it is and at times not a little obscure, hcl- riot developed markedly in the interval since 1924; but what progress has been made is covered by Dr. Mitchell in this edition in a very thorough manner. He has found it necessary to enlarge his work to the extent of some 20 per cent. and, in addition, to rewrite a large portion. The arrangement of the book follows the lines of previous editions. After a comprehensive historical introduction, the work is divided into three sections dealing with writing inks, printing inks, and inks for miscellaneous purposes, respectively. Under Section 1 are considered the chemical nature and treatment of the various raw materials used for writing inks from lcmp black to galls, the composition of finished iron-gall, logwood, vanadium, aniline black, and coloured inks, as well as a comprehensive scheme €or the tech~ical examination of inks, handwriting specimens and the identification of forge:-ies.Section 2 deals with the manufacture and examination of printing inks. ,tnd Section 3 with the miscellaneous materials entering into the compositilxx of copying, marking, safety, sympathetic, typewriter inks and so on. Amongst new matter may be noted references to the use of lignone sulphni--,ites in connection with writing ink, a scheme for the identification of individual con- stituents in inks in the form of writing, and the application of filtered ultra-.& if )let light and of infra-red photography in the elucidation of those problems to which such methods are suited.The British Government Standard Specificatior:s for Writing Inks, revised in 1928, are included for the first time. The avaihble evidence upon the constitution of gallotannin is brought up to date and <tbly reviewed, and there is a Comprehensive list of British patents. It is as difficult to withhold admiration of the encyclopaedic scope cjf the matter and references in this book as it is of the erudition and industry displiiyed in its compilation. Practically nothing that comes to mind has escaped atterition, and it is with rather impish glee that the reviewer, after careful search, asserts that he finds no specific reference to the type of alkaline (ammoniacal) gallotannate- iron ink, said t o find favour in the United States, although the di-ammonium hydroxyferrigallate compound of Silbermann and Ozorovitz receives notice.Nor is there mention of that class of quick-drying writing fluids which depend for their efficiency upon partial destruction of the paper sizing by caustic alk 1.5 or sodium silicate. There is no evidence that lignone sulphonate inks have proved se-rious competitors to iron-gall writing inks (pp. 15 and 175). Apart from the unkttmwn quantity of permanence, the principal failing of this type lies in their liability to contain traces of free sulphurous acid to which suspicion attaches in connt-ction426 REVIEWS INKS : THEIR COMPOSITION AND MANUFACTURE. By C. AINSWORTH MITCHELL, D.Sc., F.I.C.Fourth Edition. Pp. xi + 408. London: Charles Grihn tt Co., Ltd. 1937. Price 12s. 6d. net. This, the fourth edition of the standard and, indeed, so far as the reviewer’s knowledge goes, the only text-book on the subject in the language, bridges L gap of 13 years. The author, pre-eminent in his particular sphere, needs little more introduction to the world of technical industry than he does in his official capicity to readers of THE ANALYST, while his reputation in forensic science in all that appertains to handwriting is international. The chemistry of ink, difficult as it is and at times not a little obscure, hcl- riot developed markedly in the interval since 1924; but what progress has been made is covered by Dr. Mitchell in this edition in a very thorough manner.He has found it necessary to enlarge his work to the extent of some 20 per cent. and, in addition, to rewrite a large portion. The arrangement of the book follows the lines of previous editions. After a comprehensive historical introduction, the work is divided into three sections dealing with writing inks, printing inks, and inks for miscellaneous purposes, respectively. Under Section 1 are considered the chemical nature and treatment of the various raw materials used for writing inks from lcmp black to galls, the composition of finished iron-gall, logwood, vanadium, aniline black, and coloured inks, as well as a comprehensive scheme €or the tech~ical examination of inks, handwriting specimens and the identification of forge:-ies.Section 2 deals with the manufacture and examination of printing inks. ,tnd Section 3 with the miscellaneous materials entering into the compositilxx of copying, marking, safety, sympathetic, typewriter inks and so on. Amongst new matter may be noted references to the use of lignone sulphni--,ites in connection with writing ink, a scheme for the identification of individual con- stituents in inks in the form of writing, and the application of filtered ultra-.& if )let light and of infra-red photography in the elucidation of those problems to which such methods are suited. The British Government Standard Specificatior:s for Writing Inks, revised in 1928, are included for the first time. The avaihble evidence upon the constitution of gallotannin is brought up to date and <tbly reviewed, and there is a Comprehensive list of British patents.It is as difficult to withhold admiration of the encyclopaedic scope cjf the matter and references in this book as it is of the erudition and industry displiiyed in its compilation. Practically nothing that comes to mind has escaped atterition, and it is with rather impish glee that the reviewer, after careful search, asserts that he finds no specific reference to the type of alkaline (ammoniacal) gallotannate- iron ink, said t o find favour in the United States, although the di-ammonium hydroxyferrigallate compound of Silbermann and Ozorovitz receives notice. Nor is there mention of that class of quick-drying writing fluids which depend for their efficiency upon partial destruction of the paper sizing by caustic alk 1.5 or sodium silicate.There is no evidence that lignone sulphonate inks have proved se-rious competitors to iron-gall writing inks (pp. 15 and 175). Apart from the unkttmwn quantity of permanence, the principal failing of this type lies in their liability to contain traces of free sulphurous acid to which suspicion attaches in connt-ction BIOCHEMICAL 23 Biochemical Micro-determination of Serine and Ethanol- amine in Phospholipid Hydrolysates. C. F. Burmaster ( J . Bid. Chem., 1946, 165, 1-6). The method depends on measuring the ammonia formed by the action of periodate on serine and ethanolamine by the micro-diffusion technique of Conway (“ Micro- diffusion Analysis and Volumetric Error. ” London, 1939). Method-Put 1 to 5 ml.of 0.005N-hydrochloric acid containing a few drops of mixed indicator (0.08 g. of methyl red and 0.02 g. of methylene blue dissolved in 100 rnl. of 1 : 1 alcohol-water mixture and adjusted to a neutral grey colour with 0.005 N sodium hydroxide) into the central chamber of the diffusion cell and 1 to 5 ml. of the water-soluble extract from an acid hydrolysate of phospholipid into the outer chamber. The sample should contain from 0.05 to 0.3 mg. of total serine- and ethanolamine-nitrogen. Add 1 to 5 ml. of saturated potassium metaborate solution (prepared by mixing 61-9 g. of boric acid and 56.1 g. of potassium hydroxide in a mortar, and dissolving in 120 mi. of water), mix by rocking the cell, and place the cover on the cell, sliding it so as to cover all but a small portion of the outer chamber.Pipette 1 ml. of 0.05 M periodic acid through the small opening and quickly slide the cover shut. Mix the contents of the outer chamber by rotation and allow diffusion to proceed a t room temperature overnight. Titrate the standard acid remaining in the central chamber to a neutral grey colour with 0-005 N-sodium hydroxide (carbonate-free) . Carry out a similar procedure without the addition of periodate on a similar sample to serve as a “blank.” The differEnce between the values for the sample and the blank” is a measure of the serine- plus ethanolamine-nitrogen. The serine-24 ABSTRACTS OF CHEMICAL PAPERS nitrogen can be determined separately on another sample by the ninhydrin method. One ml. of 0.005 N-sodium hydroxide is equivalent to 0.007 mg.of ‘’ periodate nitrogen.” Recoveries of serine and ethanolamine added to phospholipid hydrolysates were almost theoretical. M. L. Scott, F. W. Hill, L. C. Norris, and G. F. Heuser ( J . Biol. Chem., 1946, 165, 65-71)-The method of Hodson and Norris ( J . B i d . Chem., 1939, 131, 621; ANALYST, 1940, 65, 114) has been modified to eliminate interference by highly fluorescent non- riboflavine pigments. The major modification consists in the substitution of potassium perman- ganate oxidation of the interfering pigments for the reduction procedure previously used. Method-To 1 to 5 g. of the finely ground sample in a 250-ml., red conical flask add 100 ml. of acid acetone solution (250 ml. of N-hydrochloric acid diluted to 1 litre with acetone).Heat the mixture gently under reflux for 1 hour, cool to room tem- perature, and adjust to pH 6-6 to 6.8 with trisodium phosphate solution. Dilute with water to 200 ml., leave for 5 min., and filter through a No. 12 Whatman fluted filter paper, discarding the first 10 to 20 ml. of filtrate. Pipette a 10- to 50-ml. portion of the filtrate into a 200-ml. volumetric flask, adjust the pH to 3-7 with glacial acetic acid, and add 2 ml. of 4 per cent. potassium perman- ganate solution for each 10ml. of filtrate. Leave for 3 min., and then add 3 per cent. hydrogen peroxide until the colour changes from purple to light brown. Make up to volume, add 1 to 2 g. of Celite filter aid, and filter through a No. 44 Whatman filter paper, discarding the first 10 to 20ml.of filtrate. Put 15 ml. of the remainder into the glass cell of a fluorimeter, and take the reading ( A ) after setting the galvanometer to zero with the aid of a distilled water “ blank,” and after recording the reading (S) given by a standard solution of ribo- flavine prepared as follows :- First prepare a stock solution of riboflavine by dissolving 50 mg. in a litre of water containing a few drops of glacial acetic acid to stabilise the solution, and then mix 20 ml. of this aqueous solution with 100ml. of acid acetone solution neutralised to pH 6.6 to 6-8 with trisodium phosphate solution, and dilute to 200 ml. with water. Adjust the pH of 40 ml. of this solution to 3-7 with glacial acetic acid, add 8ml. of 4 per cent. potassium permanganate solution and, after 3 min., almost decolorise the solution by means of 3 per cent.hydrogen peroxide. Dilute t o 200 ml., and filter through a No. 44 Whatman filter paper after adding Celite filter aid. Add 1 ml. of this standard riboflavine solution to 15ml. of water in the fluorimeter cell and note the reading (S). When the fluorescence ( A ) of the unknown solution has been measured, add to it 1 ml. of the standard riboflavine solution and again take a reading ( B ) . Then reduce the riboflavine to the non-fluorescing leuco form by adding 1 ml. of sodium hydrosulphite solution prepared by dis- solving 6 g. of Na$,O, in 100 ml. of 0.2 M N+HPO,, adding 1 to 2 g. of filter aid, and filtering through a No. 44 Whatman filter paper. Take a third reading ( C ) . Finally, repeat the reading (S) with the standard solution alone to ensure that the light intensity has not changed during the above opera- tions.The amount of riboflavine (pg. per g.) in the unknown solution is calculated from the exmession : F. A. R. Chemical Estimation of Riboflavine. A - (17C/15) (16 B,15) - A x 0-0626 x dilution factor A comparison of the values obtained by this method for the riboflavine contents of a wide variety of foods and feeding stuffs with those obtained by the micro-biological method shows good agreement between the two methods. Microbiological Estimation of Riboflavine in Blood. E. A . M. Bradford and H. Coke (Biochem. J., 1945, 39, 379-385)-Strong et al. ( J . .BioZ. Chem., 1941, 137, 363) estimated ribo- flavine microbiologically in whole, haemolyzed blood.This on being autoclaved, however, pro- duces a large amount of solid which makes the results somewhat variable. In the present method an acid extract of blood is prepared; this not only . eliminates most of the solid but also gives a stable extract which can be stored overnight, if desired. It is pointed out that acid‘$roduction after 72 hrs.’ incubation at any level of riboflavine is a measure of the maximum population supportable in the medium at that level, whereas after shorter periods of incubation the population may not have reached the stable maximum, so that neither acid production nor opacity will be directly proportional to the riboflavine concentration. To obtain satisfactory results therefore: (a) time must be allowed for the population to reach a stable maximum; (b) the size of the original inoculum must be standardised; and (c) the culture should be in a certain relatively deficient state.Mix 1 ml. of venous blood, immediately after withdrawal, with 4 ml. of 0.1 ’N hydrochloric acid in a conical centrifuge-tube. Plug with cotton- wool, autoclave at 15 lb. pressure for 15 mins., cool and store in the dark until required. Add 0-4 ml. of N sodium hydroxide, neutralise t o pH 4.5 with 0.02 N acetic acid and centrifuge. Transfer the supernatant liquid to a 10-ml. volu- metric flask, add 2 ml. of water to the residue, shake, centrifuge and add the washing to the flask. Wash with another 2 ml. of water, again add the washing to the flask, adjust to pH 6.7 with 0-1 N sodium hydroxide and dilute to 10 ml.Centri- fuge if necessary. Assay 2-ml. portions of the extract in duplicate by the method of Strong et al., indculating each tube with one drop of a 24-hr.-old culture introduced by means of a 1-ml. syringe fitted with a No. 10 needle from which the oblique tip has been cut. To prepare the culture, inoculate the liquid medium directly from a stab-culture, incubate for 24 hr., centrifuge and re-suspend the cells in 10 ml of sterile saline. Check the opacity by means of a Spekker photo-electric absorptiometer. With these precautions, the standard curve should be linear. The average error with 25-pg. quantities of ribo- flavine per 100 ml. was estimated to be f 8%. By destroying the riboflavine in blood by irradiation, it was shown that the riboflavine-free blood did not stimulate the growth of the organism a t any level but that, when added to known amounts of riboflavine, it exerted a marked inhibitory effect if more than 0.2 ml.was used. A method of removing this inhibitory substance has not been yet devised. F. A. R. F. A. R. Method for the Determination of Alloxan. G. Bruckmann (J. B i d . Chm., 1946, 165, 103- 113)-Alloxan in amounts ranging from 0.04 to 0.4 mg. can be determined by a method based on the following principle : (a) conversion to violuric acid by evaporation in vacm with hydroxylamine NH.CO.NH.CO.CO.CO + H,N.OH 1 1 3 NH.CO.NH.CO.C (:N.OH).CO + H,O, I IBIOCHEMICAL 26 followed by (b) photometric estimation of the violuric acid in the form of its ferrous complex 3 C,H,N,O, + FeSO, Method-Put the sample into a 50-ml.distillation flask, fitted with a fine capillary reaching exactly to the bottom, and immerse the flask in a glycerol bath. Add 1 ml. of hydroxylamine solution, prepared by dissolving 15 mg. of the hydrochloride per ml. in a mixture of equal volumes.of glycerol and absolute alcohol, and add sufficient alcohol t o bring the volume to about 20ml. Heat the bath to 40 to 50” C. and begin distillation with the aid of a water pump, raising the temperature gradually over a period of about 12 mins. to 90 to 100” C., and then within the next 5 mins., to 110 to 120°C. Allow the flask to cool in air under the reduced pressure, and then add exactly 4.5 ml. of absolute alcohol followed by 0-2 to 0.3 g. of solid quinine hydrochloride. Shake thoroughly for 1 min.to ensure complete solution, and finally add 0.1 ml. of a solution prepared by adding 3 drops of water and 6 ml. of 1 : 1 glycerol - alcohol mixture to 25 mg. of ferrous ammonium sulphate. Filter the blue solution, if necessary, and evaluate the colour in a photometer at 610mp. Calculate the results from a standard curve prepared from pure alloxan monohydrate. Alternatively, violuric acid can be used as a convenient and stable standard, but then the efficiency of the condensation procedure should be checked by comparing the calibration curve from an alloxan standard with that obtained directly from violuric acid. Each milligram of alloxan monohydrate should give the same colour as 0-97 mg. of violuric acid. All N-substituted alloxans yield blue iron violurates by this method, whilst dialuric acid and alloxantin also behave in the same way as alloxan.No colour is produced by alloxanic acid, parabanic acid, murexide, uric acid, barbituric acid, or phenobarbitone. Ninhydrin gives a brown colour. Contrary to expectations, Folin-Wu or tri- chloroacetic acid extracts of biological materials were unsatisfactory, as these filtrates contain interfering substances. Better results were obtained by treatment with ammonium sulphate, alcohol, and fuller’s earth. Procedure-Grind 1 g. of tissue with 0-5 g. of ammonium sulphate and extract the mixture with successive ’ portions of ice-cold, absolute alcohol, using a total of 20ml. Centrifuge and shake the supernatant liquid with 1 g . of fuller’s earth after adding 2 drops of N hydrochloric acid.Again centrifuge, and use the clear liquor for the colour development. In a similar way, shake 1 ml. of blood containing anticoagulant with 0.5 g. of ammonium sulphate, and then with 20 ml. of cold, absolute alcohol. Centrifuge and shake the super- natant liquid with fuller’s earth, and continue the procedure recommended for the estimation of alloxan in tissue. The recovery of alloxan from alcoholic tissue extracts was 70 to 90 per cent. of the theoretical, but recoveries from the tissues themselves were very much lower owing to the rapidity with which alloxan is destroyed by the tissues. F. A. R. + Fe(C,H,N,O,),.C,H,N,O, + HzS04. Colorimetric Estimation of Canavanine. R. M. Archibald ( J . Biol. Chem., 1946, 165, 169-178)Aanavanine reacts with a solution of sodium nitroprusside that has been exposed t o sunlight to form it ruby-coloured solution.This reaction appears to be specific for substances of the type NH II NH, - C - NH - OR and has been made the basis of a simple quantitative method of estimating canavanine. Procedure-To 1 ml. of the neutralised unknown solution containing up to 0.25 mg. of canavanine, add 0-5 ml. of M phosphate buffer solution of pH 7-2 (34-5 g. of NaH,P04.H,0 and 130.6 g. of K,HPO, in 1 litre), and 0-5 ml. of a nitroprusside reagent prepared by mixing 0-5 ml. of 20 per cent. potassium carbonate solution and 0.4ml. of 30 per cent. hydrogen peroxide with 10 ml. of 2 per cent. sodium nitroprusside solution ; after standing for 30 mins. at room temperature, this reagent, which should be prepared daily, is ready for use.Put into test tubes 0-2-, 0 6 , 04-, and 1-0-ml portions of a solution containing 0.25 mg. of canavanine per ml., and dilute each solution to 1.0ml. with water. Put 1 ml. of water into another tube to serve as a reagent “blank,” and add phosphate buffer and nitroprusside reagent t o each tube. Leave the solutions for 2 hours in the dark, and then evaluate the colours at 520 mp, after adjusting the instrument to zero by means of the blank. Calculate the canavanine content of the unknown from the curve obtained by plotting the optical density of the standard solutions against their concentrations. The method gives satisfactory results with pure solutions ; blood filtrates and urine contain un- identified substances that inhibit the development of the colour, so that in its present form the method is not applicable to these .materials.I t appears to be applicable to some plant extracts, however. The blue colours given by thiourea and other organic sulphur compounds are unstable, and are not likely to interfere with the application of the method. F. A. R. Hydrolysis Procedures for the Estimation of Tryptophan in Proteins and Foodstuffs by the Micro- biological Procedure. I. T. Green- hut, B. s. Schweigert, and C. A. Elvehjem ( J . Biol. Chem., 1946, 165, 325-332)-The liberation of tryptophan from proteins and foodstuffs by acids, alkalis, and enzymes has been investigated. The most satisfactory recoveries were obtained by incubation with a mixture of pancreatin and hog mucosa. Pancreatin alone gave wide variations in the amount of tryptophan liberated, and the addition of hog mucosa did not eliminate this variability if the solutions were not shaken.If, however, the samples were shaken continuously, the liberation achieved in one day was as great as that achieved in 5 days without shaking, and the variability between samples was almost eliminated. Procedure-Put a l-g. sample of animal tissue or 100- to 200-mg. sample of protein into a 100-ml. volumetric flask, add 50 mg. of pancreatin, and 25mg. of hog mucosa. Dilute with water to approximately 60 ml., and adjust the pH to 8.2 with 0.1 N sodium hydroxide. Cover the solution with toluene, and incubate at 37°C. with con- tinuous shaking for one day. The digest can be used for micro-biological assays by the recognised procedure.F. A. R. Determination of Sulphonamides in Tungstic Acid (Folin - Wu) Blood Filtrates. E. G. Schmidt ( J . Lab. Clan. Med.. 1946, 31, 694-699)-The determination of blood urea, non-protein nitrogen,ABSTRACTS OF CHEMICAL PAPERS sugar, etc., and of the unconjugated sulphonamides is often required for the same sample of blood. Routine blood filtrates generally contain tungstate ions, derived from the deproteinisation procedure, which interfere with the colorimetric determination of sulphonamides by the method of Bratton and Marshall ( J . Biol. Chem., 1939, 128, 537). A modification of this test is described wherein the effect of the tungstate ions is obviated. Method-Haemolyse the sample of oxalated blood by mixing 1 volume with 8 volumes of 0-0877 N sulphuric acid, adding 1 drop of N sulphuric acid as a precaution against undue alkalinity of the potassium oxalate, and precipitate the proteins with 10 per cent.sodium tungstate solution in the usual way. To 5 ml. of the deproteinised blood filtrate add 5 ml. of a 15 per cent. aqueous solution of p-toluene sulphonic acid monohydrate con- taining 2 per cent. of citric acid, and 1 ml. of a 0.1 per cent. solution of sodium nitrite. Leave for 3 min. and add 1 ml. of a 0.1 per cent. aqueous solution of N-(1-naphthy1)-ethylenediamine di- hydrochloride. Compare the red colour produced with that of the appropriate standard treated in the same manner in a Duboscq-type colorimeter. If a photo-electric instrument is used, the method is modified as follows.Add 5 ml. of the p-toluene sulphonic acid mixture, previously diluted with an equal volume of water, or of the citric acid - sulphuric acid solution, similarly diluted, to 2 ml. of the blood filtrate, 2 ml. of the appropriate standard solution, and 2 ml. of distilled water, respectively. Then add 0.5 ml. of 0.1 per cent. sodium nitrite solution to each, followed, after 3 min., by 0-5 ml. of an aqueous solution containing 0.5 per cent. of ammonium sulphamate and 13-8 per cent. of sodium dihydrogen phosphate (NaH,PO,.H,O) . Leave for a further period of 3 min. and add to each 0.5 ml. of N-( l-naphthy1)-ethylenediamine dihydrochloride solution. Set the photo-electric instrument a t zero with the water blank and then compare the colour produced by the test with that of the standard; a green filter (No.54) should be used. The standard solutions are prepared by dissolving 250 mg. of the sulphonamide (or 1 g. if sulphanilamide) in 1 litre of 0.0877 N sulphuric acid and diluting these stock solutions to form working standards of the required con- centration before use. The p-toluene sulphonic acid - citric acid solution prevents the formation of a violet tint due to the presence of tungstate ions; except with sulphathiazole, it is possible to use a 2 per cent. solution of citric acid in 0.2 N sulphuric acid in place of the more expensive p-toluene sulphonic acid mixture. It is stated that except with sulphanilamide, which gives an orange-red colour in the test, the tints produced by the various sulphonamides match each other reasonably well, and that only one standard, therefore, need be prepared, conversion factors being determined experimentally by comparative analyses.Since it is known that sulphonamides are, in some degree, adsorbed by the protein precipitate during the preparation of blood filtrates (Schmidt, J . Biol. Chem., 1938, 122, 757; J . Lab. Clin. Med.. 1939, 24, 982; Scudi, J . Biol. Chem., 1938, 122, 539), percentage recoveries have been determined and found to be consistent and independent of the initial concentration of the drug in the blood. At 26" C., the figures obtained are: sulphanilamide, 88.3% ; sulphadiazine, 75.7% : sodium sulphadiazine, 75.8% ; sulphamerazine, 75.8% ; sulphamethazine, 76-1 % : sulphapyridine, 74.4% : sulphathiazole, 66.7% ; and sulphacetamide, 83.8%.These values are slightly higher (from 2 to 6%) at 33"C., and slightly lower (from 0-5 to 2%) at 18" C. Com- parison of the results obtained on whole blood by the method of Bratton and Marshall (loc. ciC.) and the proposed modification indicates that agreement is satisfactory. J. A. Polarographic Estimation of Steroid Hor- mones. Polarography of Neutral 17-Keto- steroids in Urinary Extracts. J. Barnett, A. A. Henly, and C. J. 0. R. Morris (Biochem. J., 1946, 40, 445--449)-Wolfe et al. ( J . Biol. Chem,, 1940, 136, 653) showed that certain ketosteroids condensed with the Girard T reagent to give water- soluble hydrazones, which under suitable conditions yielded well-defined polarographic waves. The wave span was proportional to the steroid concen- tration over a considerable range and amounts of the order of 10 pg.could be estimated with accuracy. This wave appears to be specific for 17-ketosteroids. The method was later extended ( J . Bid. Chem., 1941, 140, 215) to hydroxysteroids, which were oxidised to the corresponding ketones. In applying this method to the estimation of 17-ketosteroids in urinary extracts, it was found that the form of the wave was distorted because, (a) the final discharge occurred a t a lower voltage, so that the point of inflexion of the wave was difficult to distinguish, and ( b ) a second small wave extending from about -1.0 to - 1 . 3 ~ . made it difficult to establish a true base line. The inter- fering substance was ketonic in nature, since extracts not treated with Girard T reagent gave no polaro- graphic wave.The difficulties arising from the presence of this impurity were overcome (a) by decreasing the rate of rise of applied voltage as suggested by Werthessen and Baker (Endocrinology, 1945, 36, 351), and (b) by destroying a considerable proportion of the impurity by oxidation with potassium permanganate in aqueous dioxan. Heat a portion of the urine, estimated to contain 0.5 to 1 mg. of ketosteroids, rapidly to boiling and add 15ml. of conc. hydrochloric acid per 100ml. of urine. Continue boiling under reflux for exactly 10 mins., cool immediately and add 26 g. of sodium chloride. Extract with four 50-ml. portions of benzene, wash the combined extracts twice with a 9% solution of sodium carbonate and evaporate under reduced pressure to slightly less than 100 ml.Transfer to a separating funnel and rinse out the flask with sufficient benzene to bring the total volume to 100ml. Remove phenols by shaking with four 25-ml. portions of 2 N sodium hydroxide and then shake with 25 ml. of a freshly prepared 10% solution of sodium hyposulphite in 2 N sodium hydroxide for 3 mins., keeping the separator stop- pered the whole time. Finally wash with four 2.5-ml. portions of water and distil the colourless benzene extract to dryness under reduced pressure, first in a bath a t about 6OOC. and finally a t room temperature. Dissolve the residue in 1-Oml. of pure benzene. To purify this crude extract, evaporate 0.1 ml. to dryness under reduced pressure and dissolve the residue in 0.5 ml. of freshly redistilled dioxan, add 0.1 ml.of 0.1 N potassium permanganate solution and 0.25 ml. of 0-01 N periodic acid, stopper the tube and leave it at room temperature for 15 mins. Transfer the solution to a separating funnel, rinsing out the tube with 5ml. of benzene and 5ml. of water. Shake and discard the lower layer. Shake the benzene solution with 3 ml. of a freshly prepared 10% solution of sodium hypo- sulphite in 2 N sodium hydroxide and then four This is the crude extract.BIOCHEMICAL 27 times with water. Evaporate the benzene extract to dryness. This is the oxidised extract. To prepare the Girard T hydrazones, evaporate 0.1 ml. of the crude extract to dryness under reduced pressure at 30°C. and to the residue, or to the total residue from the oxidised extfact, add 0-02 ml.of a freshly prepared solution containing 20 mg. of Girard T reagent in 0.2 ml. of pure acetic acid. Stopper the tube and heat in a boiling water bath for 2 mins. Cool, add 2 ml. of the base solution (a 1 :2: 1 mixture of 0.5 N sodium chloride, 0.2 N sodium hydroxide and water) and transfer the clear solution to the polarographic cell. Add about 1 ml. of mercury and pass a rapid stream of nitrogen through the solution for 3 mins. Insert the dropping electrode and measure the current in the usual way over a potential range of -0.9 to - 1-8 volts. F. A. R. Photometric Determination of Total Chole- sterol in Plasma or Serum by a Modified Liebermann-Burchard Reaction. A. Saifer and 0. F. Kammerer (1. B i d . Chem., 1946, 164, 657-677)-The new method differs from those previously described in that no attempt is made to remove the water from the biological fluid; instead an amount of water, equivalent to that present in the biological fluid, is added to the cholesterol standards. In the course of the reaction the water present in the standard or unknown is converted into acetic acid.It is well-known that the Liebermann-Burchard reaction takes place in acetic acid solution as well as in chloroform, although the rate of reaction vanes with the nature of the solvent. Pipette duplicate 0.20-ml. samples of clear un- haemolysed serum or plasma into test tubes con- taining 5 ml. of acetic anhydride - dioxan mixture (3:2). Mix well and heat in a boiling water bath for 30mins. with occasional shaking. Filter the solution through a Whatman No.428filter paper into graduated colorimeter tubes. Rinse the original tubes with 0-25-ml. portions of the acetic anhydride - dioxan mixture, filter, combine the filtrate and washings, and adjust the final vdume to 5.00ml. To each tube add 0-25ml. of conc. sulphuric acid from a micro-burette, mix well and, exactly 5 mins. later, immerse the tube in a water bath maintained at 37.5” C. Five mins. later, remove the tube and evaluate the colour in a photo- electric colorimeter with a 650mp filter against a reagent blank set a t 100% transmission. Take readings at 5-minute intervals until the maximum density value is reached. Calculate the cholesterol content corresponding to this maximum density from a standard curve prepared from solutions con- taining 0.2 to 1-2 mg.of cholesterol and 0.18 ml. of water. A more satisfactory standard for use in the assay of plasma or serum is made by dissolving 25 mg. of cholesterol and 27.7 mg. of cholesteryl acetate in 240 ml. of the acetic anhydride - dioxan mixture by heating, cooling to room temperature and diluting to 250ml. with the solvent mixture. The recoveries of cholesterol, cholesterol ester or mixtures of both added to normal human serum were almost theoretical. Activated Glycerol Dichlorohydrin. A New Colorimetric Reagent for Vitamin A. A. E. Sobel and H. Werbin (Ind. Eng. Chem., Anal. Ed., 1946, 18, 570-673)-Recently (J. Biol. Chem., 1945, 159, 681; ANALYST, 1946, 17, 43) the authors pro- posed the use of glycerol 1:Bdichlorohydrin as a new reagent for the quantitative estimation of vitamin A.It has since been found that some com- F. A. R. mercial samples of the dichlorohydrin do not give colour when added to vitamin A. By distilling these with 1 to 5% of antimony trichloride at 4- to 40-mm. pressure, a reagent was obtained which reacted satisfactorily with vitamin A. Activation could also be obtained by addition of conc. hydro- chloric acid, acetyl chloride, phosphorus penta- chloride, anhydrous aluminium chloride and benzoyl chloride, but conc. sulphuric acid, zinc chloride and stannic chloride caused the reagent to give blue colours that did not change to violet. Glycerol 2 : 3-dichlorohydrin and glycerol 1 :3-dibromohydrin when activated gave blue colours changing to violet. The concn. of antimony (as antimony trichloride) in the activated reagent varied from a trace to 0-67%, but the activation is not due to antimony trichloride per se, since glycerol dichloro- hydnn to which 0.1 to 1.0% of antimony trichloride had been added was inactive towards vitamin A. Although the activated reagent and the original reagent react in a similar manner towards vitamin A, the activated reagent behaves differently to- wards carotene and various sterols.A spectro- photometric study was made of the violet colour produced by the activated reagent with vitamin A in chloroform soln. The colour was found to be stable for 2 to 10 min after addition of the reagent a t 555 mp. the wavelength of maximum absorption, and the colour obeys Beer’s law over a wide range. With the Beckman Quartz Spectrophotometer with a band width of 5 mp or less, the extinction coefficient of the coloured liquid produced by the activated reagent with crystalline vitamin A alcohol was 1270 at its wavelength of maximum absorption, viz., 553-556 mp.The corresponding coefficient for the crystalline acetate was 1350 calculated for its vitamin A content. The lower extinction of the alcohol was subsequently shown to be due to some impurity in the vitamin alcohol. With the Beck- man spectrophotometer a nearly linear relation was found between the optical density and vitamin A concns. ranging from 1-36 to 13-63 pg. per 5 ml., the average extinction being 1300 f 24. With the Coleman Universal Spectrophotometer with its 35-mp band width a linear. relation existed within a smaller concn. range, vzz., 1-36 to 5.5pg. per 6 ml., the average extinction being 1120 f 15. The interference of carotene, vitamin D, and other related sterols in the estimation of vitamin A with the activated reagent was investigated by measuring the absorption of the coloured s o h . produced under the conditions of the vitamin A estimation. Except with carotene the interference was negligible. The error due to an equal wt. of carotene was 11 yo with the CoIeman spectrophotometer and 7.35% with the Beckman instrument. This may be com- pared with a 5% interference in the antimony trichloride method. The carotene interference may b e evaluated by the method of Dann and Evelyn (Biochem. J., 1938, 32, 1008) with the activated reagent just as with antimony trichloride. The absorption curves of crystalline vitamin A acetate and carotene treated with the reagent show that above 630mp the vitamin A product no longer absorbs light, whereas the carotene product con- tinues to do so beyond this point. Thus by taking readings a t two wavelengths, viz., 555 and 800mp, both carotene and vitamin A can be evaluated, the optical densities being additive. To prepare the reagent add 100 ml. of chloroform containing 10 to 60g. of dissolved antimony tri- chloride (prepared without “anhydrous” precautions) to 1000 ml. of glycerol dichlorohydrin. Distil the mixture under reduced pressure (4 to 40 mm.) in an28 ABSTRACTS OF CHEMICAL PAPERS all-glass apparatus. Discard the chloroform frac- tion and collect and store the product in a glass- stoppered bottle at room temp. Some samples of dichlorohydrin required two distillations to produce a colourless reagent. To develop the colour add 1 ml. of chloroform containing the desired amount of vitamin A or carotene, or both, to 4 ml. of activated reagent, shake the mixture thoroughly and main- tain it at 25" C. in a water bath until ready for the spectrophotometer, the colour being stable for 8 min. The colour is not affected by water present in a humid atmosphere, and the reagent does not leave white deposits of antimony oxychloride in the photometer cells. A.O. J.

ISSN:0003-2654    

DOI:10.1039/AN9477200023

出版商:RSC    

年代:1947

数据来源: RSC

摘要:

426 REVIEWS INKS : THEIR COMPOSITION AND MANUFACTURE. By C. AINSWORTH MITCHELL, D.Sc., F.I.C. Fourth Edition. Pp. xi + 408. London: Charles Grihn tt Co., Ltd. 1937. Price 12s. 6d. net. This, the fourth edition of the standard and, indeed, so far as the reviewer’s knowledge goes, the only text-book on the subject in the language, bridges L gap of 13 years. The author, pre-eminent in his particular sphere, needs little more introduction to the world of technical industry than he does in his official capicity to readers of THE ANALYST, while his reputation in forensic science in all that appertains to handwriting is international. The chemistry of ink, difficult as it is and at times not a little obscure, hcl- riot developed markedly in the interval since 1924; but what progress has been made is covered by Dr.Mitchell in this edition in a very thorough manner. He has found it necessary to enlarge his work to the extent of some 20 per cent. and, in addition, to rewrite a large portion. The arrangement of the book follows the lines of previous editions. After a comprehensive historical introduction, the work is divided into three sections dealing with writing inks, printing inks, and inks for miscellaneous purposes, respectively. Under Section 1 are considered the chemical nature and treatment of the various raw materials used for writing inks from lcmp black to galls, the composition of finished iron-gall, logwood, vanadium, aniline black, and coloured inks, as well as a comprehensive scheme €or the tech~ical examination of inks, handwriting specimens and the identification of forge:-ies.Section 2 deals with the manufacture and examination of printing inks. ,tnd Section 3 with the miscellaneous materials entering into the compositilxx of copying, marking, safety, sympathetic, typewriter inks and so on. Amongst new matter may be noted references to the use of lignone sulphni--,ites in connection with writing ink, a scheme for the identification of individual con- stituents in inks in the form of writing, and the application of filtered ultra-.& if )let light and of infra-red photography in the elucidation of those problems to which such methods are suited. The British Government Standard Specificatior:s for Writing Inks, revised in 1928, are included for the first time. The avaihble evidence upon the constitution of gallotannin is brought up to date and <tbly reviewed, and there is a Comprehensive list of British patents.It is as difficult to withhold admiration of the encyclopaedic scope cjf the matter and references in this book as it is of the erudition and industry displiiyed in its compilation. Practically nothing that comes to mind has escaped atterition, and it is with rather impish glee that the reviewer, after careful search, asserts that he finds no specific reference to the type of alkaline (ammoniacal) gallotannate- iron ink, said t o find favour in the United States, although the di-ammonium hydroxyferrigallate compound of Silbermann and Ozorovitz receives notice. Nor is there mention of that class of quick-drying writing fluids which depend for their efficiency upon partial destruction of the paper sizing by caustic alk 1.5 or sodium silicate.There is no evidence that lignone sulphonate inks have proved se-rious competitors to iron-gall writing inks (pp. 15 and 175). Apart from the unkttmwn quantity of permanence, the principal failing of this type lies in their liability to contain traces of free sulphurous acid to which suspicion attaches in connt-ction426 REVIEWS INKS : THEIR COMPOSITION AND MANUFACTURE. By C. AINSWORTH MITCHELL, D.Sc., F.I.C. Fourth Edition. Pp. xi + 408. London: Charles Grihn tt Co., Ltd. 1937. Price 12s. 6d. net. This, the fourth edition of the standard and, indeed, so far as the reviewer’s knowledge goes, the only text-book on the subject in the language, bridges L gap of 13 years. The author, pre-eminent in his particular sphere, needs little more introduction to the world of technical industry than he does in his official capicity to readers of THE ANALYST, while his reputation in forensic science in all that appertains to handwriting is international.The chemistry of ink, difficult as it is and at times not a little obscure, hcl- riot developed markedly in the interval since 1924; but what progress has been made is covered by Dr. Mitchell in this edition in a very thorough manner. He has found it necessary to enlarge his work to the extent of some 20 per cent. and, in addition, to rewrite a large portion. The arrangement of the book follows the lines of previous editions. After a comprehensive historical introduction, the work is divided into three sections dealing with writing inks, printing inks, and inks for miscellaneous purposes, respectively.Under Section 1 are considered the chemical nature and treatment of the various raw materials used for writing inks from lcmp black to galls, the composition of finished iron-gall, logwood, vanadium, aniline black, and coloured inks, as well as a comprehensive scheme €or the tech~ical examination of inks, handwriting specimens and the identification of forge:-ies. Section 2 deals with the manufacture and examination of printing inks. ,tnd Section 3 with the miscellaneous materials entering into the compositilxx of copying, marking, safety, sympathetic, typewriter inks and so on. Amongst new matter may be noted references to the use of lignone sulphni--,ites in connection with writing ink, a scheme for the identification of individual con- stituents in inks in the form of writing, and the application of filtered ultra-.& if )let light and of infra-red photography in the elucidation of those problems to which such methods are suited.The British Government Standard Specificatior:s for Writing Inks, revised in 1928, are included for the first time. The avaihble evidence upon the constitution of gallotannin is brought up to date and <tbly reviewed, and there is a Comprehensive list of British patents. It is as difficult to withhold admiration of the encyclopaedic scope cjf the matter and references in this book as it is of the erudition and industry displiiyed in its compilation.Practically nothing that comes to mind has escaped atterition, and it is with rather impish glee that the reviewer, after careful search, asserts that he finds no specific reference to the type of alkaline (ammoniacal) gallotannate- iron ink, said t o find favour in the United States, although the di-ammonium hydroxyferrigallate compound of Silbermann and Ozorovitz receives notice. Nor is there mention of that class of quick-drying writing fluids which depend for their efficiency upon partial destruction of the paper sizing by caustic alk 1.5 or sodium silicate. There is no evidence that lignone sulphonate inks have proved se-rious competitors to iron-gall writing inks (pp. 15 and 175). Apart from the unkttmwn quantity of permanence, the principal failing of this type lies in their liability to contain traces of free sulphurous acid to which suspicion attaches in connt-ction426 REVIEWS INKS : THEIR COMPOSITION AND MANUFACTURE.By C. AINSWORTH MITCHELL, D.Sc., F.I.C. Fourth Edition. Pp. xi + 408. London: Charles Grihn tt Co., Ltd. 1937. Price 12s. 6d. net. This, the fourth edition of the standard and, indeed, so far as the reviewer’s knowledge goes, the only text-book on the subject in the language, bridges L gap of 13 years. The author, pre-eminent in his particular sphere, needs little more introduction to the world of technical industry than he does in his official capicity to readers of THE ANALYST, while his reputation in forensic science in all that appertains to handwriting is international. The chemistry of ink, difficult as it is and at times not a little obscure, hcl- riot developed markedly in the interval since 1924; but what progress has been made is covered by Dr.Mitchell in this edition in a very thorough manner. He has found it necessary to enlarge his work to the extent of some 20 per cent. and, in addition, to rewrite a large portion. The arrangement of the book follows the lines of previous editions. After a comprehensive historical introduction, the work is divided into three sections dealing with writing inks, printing inks, and inks for miscellaneous purposes, respectively. Under Section 1 are considered the chemical nature and treatment of the various raw materials used for writing inks from lcmp black to galls, the composition of finished iron-gall, logwood, vanadium, aniline black, and coloured inks, as well as a comprehensive scheme €or the tech~ical examination of inks, handwriting specimens and the identification of forge:-ies.Section 2 deals with the manufacture and examination of printing inks. ,tnd Section 3 with the miscellaneous materials entering into the compositilxx of copying, marking, safety, sympathetic, typewriter inks and so on. Amongst new matter may be noted references to the use of lignone sulphni--,ites in connection with writing ink, a scheme for the identification of individual con- stituents in inks in the form of writing, and the application of filtered ultra-.& if )let light and of infra-red photography in the elucidation of those problems to which such methods are suited. The British Government Standard Specificatior:s for Writing Inks, revised in 1928, are included for the first time.The avaihble evidence upon the constitution of gallotannin is brought up to date and <tbly reviewed, and there is a Comprehensive list of British patents. It is as difficult to withhold admiration of the encyclopaedic scope cjf the matter and references in this book as it is of the erudition and industry displiiyed in its compilation. Practically nothing that comes to mind has escaped atterition, and it is with rather impish glee that the reviewer, after careful search, asserts that he finds no specific reference to the type of alkaline (ammoniacal) gallotannate- iron ink, said t o find favour in the United States, although the di-ammonium hydroxyferrigallate compound of Silbermann and Ozorovitz receives notice.Nor is there mention of that class of quick-drying writing fluids which depend for their efficiency upon partial destruction of the paper sizing by caustic alk 1.5 or sodium silicate. There is no evidence that lignone sulphonate inks have proved se-rious competitors to iron-gall writing inks (pp. 15 and 175). Apart from the unkttmwn quantity of permanence, the principal failing of this type lies in their liability to contain traces of free sulphurous acid to which suspicion attaches in connt-ction426 REVIEWS INKS : THEIR COMPOSITION AND MANUFACTURE. By C. AINSWORTH MITCHELL, D.Sc., F.I.C. Fourth Edition. Pp. xi + 408. London: Charles Grihn tt Co., Ltd. 1937. Price 12s. 6d. net. This, the fourth edition of the standard and, indeed, so far as the reviewer’s knowledge goes, the only text-book on the subject in the language, bridges L gap of 13 years.The author, pre-eminent in his particular sphere, needs little more introduction to the world of technical industry than he does in his official capicity to readers of THE ANALYST, while his reputation in forensic science in all that appertains to handwriting is international. The chemistry of ink, difficult as it is and at times not a little obscure, hcl- riot developed markedly in the interval since 1924; but what progress has been made is covered by Dr. Mitchell in this edition in a very thorough manner. He has found it necessary to enlarge his work to the extent of some 20 per cent. and, in addition, to rewrite a large portion.The arrangement of the book follows the lines of previous editions. After a comprehensive historical introduction, the work is divided into three sections dealing with writing inks, printing inks, and inks for miscellaneous purposes, respectively. Under Section 1 are considered the chemical nature and treatment of the various raw materials used for writing inks from lcmp black to galls, the composition of finished iron-gall, logwood, vanadium, aniline black, and coloured inks, as well as a comprehensive scheme €or the tech~ical examination of inks, handwriting specimens and the identification of forge:-ies. Section 2 deals with the manufacture and examination of printing inks. ,tnd Section 3 with the miscellaneous materials entering into the compositilxx of copying, marking, safety, sympathetic, typewriter inks and so on.Amongst new matter may be noted references to the use of lignone sulphni--,ites in connection with writing ink, a scheme for the identification of individual con- stituents in inks in the form of writing, and the application of filtered ultra-.& if )let light and of infra-red photography in the elucidation of those problems to which such methods are suited. The British Government Standard Specificatior:s for Writing Inks, revised in 1928, are included for the first time. The avaihble evidence upon the constitution of gallotannin is brought up to date and <tbly reviewed, and there is a Comprehensive list of British patents. It is as difficult to withhold admiration of the encyclopaedic scope cjf the matter and references in this book as it is of the erudition and industry displiiyed in its compilation.Practically nothing that comes to mind has escaped atterition, and it is with rather impish glee that the reviewer, after careful search, asserts that he finds no specific reference to the type of alkaline (ammoniacal) gallotannate- iron ink, said t o find favour in the United States, although the di-ammonium hydroxyferrigallate compound of Silbermann and Ozorovitz receives notice. Nor is there mention of that class of quick-drying writing fluids which depend for their efficiency upon partial destruction of the paper sizing by caustic alk 1.5 or sodium silicate. There is no evidence that lignone sulphonate inks have proved se-rious competitors to iron-gall writing inks (pp.15 and 175). Apart from the unkttmwn quantity of permanence, the principal failing of this type lies in their liability to contain traces of free sulphurous acid to which suspicion attaches in connt-ction426 REVIEWS INKS : THEIR COMPOSITION AND MANUFACTURE. By C. AINSWORTH MITCHELL, D.Sc., F.I.C. Fourth Edition. Pp. xi + 408. London: Charles Grihn tt Co., Ltd. 1937. Price 12s. 6d. net. This, the fourth edition of the standard and, indeed, so far as the reviewer’s knowledge goes, the only text-book on the subject in the language, bridges L gap of 13 years. The author, pre-eminent in his particular sphere, needs little more introduction to the world of technical industry than he does in his official capicity to readers of THE ANALYST, while his reputation in forensic science in all that appertains to handwriting is international.The chemistry of ink, difficult as it is and at times not a little obscure, hcl- riot developed markedly in the interval since 1924; but what progress has been made is covered by Dr. Mitchell in this edition in a very thorough manner. He has found it necessary to enlarge his work to the extent of some 20 per cent. and, in addition, to rewrite a large portion. The arrangement of the book follows the lines of previous editions. After a comprehensive historical introduction, the work is divided into three sections dealing with writing inks, printing inks, and inks for miscellaneous purposes, respectively. Under Section 1 are considered the chemical nature and treatment of the various raw materials used for writing inks from lcmp black to galls, the composition of finished iron-gall, logwood, vanadium, aniline black, and coloured inks, as well as a comprehensive scheme €or the tech~ical examination of inks, handwriting specimens and the identification of forge:-ies.Section 2 deals with the manufacture and examination of printing inks. ,tnd Section 3 with the miscellaneous materials entering into the compositilxx of copying, marking, safety, sympathetic, typewriter inks and so on. Amongst new matter may be noted references to the use of lignone sulphni--,ites in connection with writing ink, a scheme for the identification of individual con- stituents in inks in the form of writing, and the application of filtered ultra-.& if )let light and of infra-red photography in the elucidation of those problems to which such methods are suited.The British Government Standard Specificatior:s for Writing Inks, revised in 1928, are included for the first time. The avaihble evidence upon the constitution of gallotannin is brought up to date and <tbly reviewed, and there is a Comprehensive list of British patents. It is as difficult to withhold admiration of the encyclopaedic scope cjf the matter and references in this book as it is of the erudition and industry displiiyed in its compilation. Practically nothing that comes to mind has escaped atterition, and it is with rather impish glee that the reviewer, after careful search, asserts that he finds no specific reference to the type of alkaline (ammoniacal) gallotannate- iron ink, said t o find favour in the United States, although the di-ammonium hydroxyferrigallate compound of Silbermann and Ozorovitz receives notice.Nor is there mention of that class of quick-drying writing fluids which depend for their efficiency upon partial destruction of the paper sizing by caustic alk 1.5 or sodium silicate. There is no evidence that lignone sulphonate inks have proved se-rious competitors to iron-gall writing inks (pp. 15 and 175). Apart from the unkttmwn quantity of permanence, the principal failing of this type lies in their liability to contain traces of free sulphurous acid to which suspicion attaches in connt-ction 28 ABSTRACTS OF CHEMICAL PAPERS Organic The Specificity of the Salicylaldehyde Re- action for the Detection of Acetone.T. Thomson (1. Soc. Chem. Ind., 1946, 65, 121-124)- Braunstein’s theory (Nature, 1937, 140, 427) of the mechanism of the salicylaldehyde reaction for detecting acetone is rejected, and it is shown that the reaction is less selective than was stated by Braunstein. The reaction evidently involves con- densation of the salicylaldehyde with a methylene group in the cc-position to an unsaturated group such as carbonyl, .and the formation of an alkali salt of the resulting resonating structure : 0 MetholGFor the test, use aqueous solutions; dissolve in alcohol substances insoluble in water, and dilute with water. Place in a test tube 5ml. of the solution under examination, and add 4 ml. of 40 per cent. sodium hydroxide solution, followed by 1 ml.of reagent prepared by diluting 20 ml. of salicylaldehyde to 100 ml. with 96 per cent. alcohol, Heat the reactants a t 40 to 50” C. for 20 mins., and compare the colour with that of a “ blank I’ carried out simultaneously on the reagents. The following results were obtained. Substance Acetone .. #I 1 , .. .. ,. .. Pyruvic acid . . E t i i l ace&aceke 3. I # ,, I , Acetophenone . . Benzalacetone ,* .. Acetaldehyde . . Propionaldehyde Methyl Lihyl ketone Dieihyl kitone ” Cyclohexanone .. .. .. .. .. .. .. .. .. .. .. .. .. . . .. .. .. .. . . * . The constitution of the coloured products has been examined. That formed with acetone is the monosodium salt of o-hydroxybenzalacetone (salicylacetone) ; the neutral material precipitated from the aqueous solution on titration with acid had, after recrystallisation from aqueous alcohol, m.p.137” to 139°C. The product formed with benzalacetone is the monosodium salt of salicyl- benzalacetone. Ethyl acetoacetate gives the sodium salt of salicylacetone, evidently formed by normal ketonic hydrolysis from the condensation product of salicylaldehyde and ethyl acetoacetate. Aceto- phenone gives the sodium salt of salicylaceto- phenone ; the neutral material obtained after acidification of the salt had m.p. 154” to 156°C. Analytical Reactions with Organic Re- agents. A. Steigmann (J. Soc. Chem. Ind., 1946, 65, 233-234)-The following specific or very selective reagents are described. (1) A sensilivs reagent for thiosulphate-By heating, dissolve 0.1 g.of thionine (B.D.H. redox indicator) in 50ml. of ethylene glycol or other inert alcohol. Add 1 ml. of this solution to 50ml. of water and dilute to 100 ml. To 3ml. of the carbon-filtered and then evaporated wash water of the gelatin to be tested, or other test solution, add 1 ml. of the diluted thionine solution. Perform a “blank” test. To the test and the “blank,” add 0.4 ml. of 5 N sulphuric acid. Stand both in boiling water for 7 to 8 min., and cool in running cold water for 20 min. Less than 1 : 40,000 sodium thiosulphate causes a colour change from violet to blue, whilst higher concentrations cause partial or total bleaching. The new test is less sensitive, but much more selective than the iodine-azide reaction. Only thiocarbamides interfere at 50 to 100 times higher concentrations by giving direct bleaching without prior colour change.(2) Specijic reagents for nitrate, guanidine, urea, and nztroso-compounds-(a) Add 1 g. of carbazole to 100ml. of isopropyl alcohol, followed by 1-4g. of dimethylglyoxime. Dissolve by heating. E. M. P. Concentration of soln. used for test (parts by volume) 1 in 50,000 1 in 250,000 1 in 6,250,000 1 in 12,500,000 1 in 50,000 1 in 260,000 1 in 200 1 in 500 1 in 250,000 1 in 200 1 in 100,000 1 in 250,000 1 in 500 1 in 600 1 in 125,000 1 in 500 1 in 50,000 1 in 500 1 in 500 1 in 250.000 Methyl cyclohexanone 1 in 500 Cyanacetic acid . . Approx. 3 in 100 Fluorene .. .. *. s, 1 in 50,000 - Colour obtained in test Red Red with yellowish tinge Pale orange; definitely deeper colour than reagents alone Lemon-yellow, indistinguishable from reagents alone.Red with yellowish tinge Pale orange, definitely deeper than reagents alone Orange-red Brownish- yellow Golden-yellow, just distinguishable when compared directly with lemon-yellow colour of reagents Bright red Lemon-yellow, indistinguishable from reagents Golden-yellow, just distinguishable when compared directly with lemon-yellow colour of reagents Golden-yellow, just distinguishable when compared directly with lemon-yellow colour of reagents Deep orange Lemon-yellow, indistinguishable from reagents Orange Golden-yellow, deeper than reagents Solden-yellow, decidedly deeper than reagents Deep orange Yellow, barely distinguishable from reagents Orange Lemon-yellow, indistinguishable from reagents Deep orange No reactionORGANIC Crystals precipitate on cooling, and are dissolved again before use.To 3 ml. of concentrated hydro- chloric acid add 0.5 ml. of 1 per cent, arginine hydro- chloride, or guanidine carbonate solution. or 1 ml. of 10 per cent. gelatin solution (as a source of arginine), and then 0.2 ml. of the reagent, followed by I to several drops of the test solution, or of water for the “blank.” Heat for 20 min. in boiling water. Traces of nitrate produce a brilliant blue coloration. By using a small amount of nitrate in the reagent instead of guanidine, the reagent can be used to test for guanidine (arginine). To 3-5 ml. of concentrated hydrochloric acid add 1 ml. of 2 per cent. gelatin solution, 2 drops of 1 per cent. potassium nitrate solution, and 0.5 ml.of the reagent. Boil for 12 min. By dissolving in 10 ml. of isopropyl alcohol the precipitate from an excess of carbazole, the blue colour goes into the aqueous solution, which can then be used for colorimetric determination of nitrate. (b) To 3 ml. of concentrated hydrochloric acid add 0.5 ml. of 0-5 per cent. alcoholic acetyl benzoyl solution, 0-2 ml. of 10 per cent. urea solution, and 1 ml. of nitrate test solution. Roil for 10 min. Nitrates cause the development of a stable, carmine colour, suitable for colorimetric determinations. Guanidines (arginine) do not interfere. The reaction is specific for ureas (citrulline) when, instead of urea, nitrate is included in the reagent. To detect citrulline in gelatin, add 2 drops of 1 per cent. potassium nitrate solution, and 0.5 ml.of 0.5 per cent. alcoholic acetyl benzoyl solution to 3 ml. of concentrated hydrochloric acid, followed by 0.5 ml. of water and 1 g. of gelatin powder. Boil for 6 min. The reagent cannot be used for proteins containing tryptophan and sugars, or giving a strong humin reaction on acid hydrolysis. A slight humin reaction is given by gelatins, but this does not interfere seriously. (c) Cheaper reagents for nitrate or urea are obtained by substituting dimethylglyoxime or diacetylmonoxime for acetyl benzoyl in (b). The reactions for nitrate described above are not interfered with by traces of nitrite, and are as sensitive as the nitrate reactions with polyhydric phenols. Resorcinol, a 1 per cent. solution in concentrated hydrochloric acid, is also a reagent for nitroso- compounds, such as a-nitroso- 8-naphthol and nitroso-R-salt.Add 3 ml. of the resorcinol solution to the evaporated test solution; transfer to a test tube, and put into boiling water, whereupon there develops a blue-violet colour which, after dilution with water, can be extracted with ether. The colour in ether is red. Resorcinol in concentrated sulphuric acid reacts also with some nitro-com- pounds, e.g., with p-nitrophenylhydrazine, but not with 2 : 4-dinitrophenylhydrazine, giving sulphon- ated dyes which are not extracted by ether. The dyes from the resorcinol nitrate and nitrite reactions are also soluble in ether. Resorcinol cannot be used for gelatin in Selivanov’s sugar reaction, as technical gelatins invariably contain traces of nitrates, or nitrites, or both.(3) Reagents for carbohydrate-sugar-(a) Dissolve 80 g . of urea in 200ml. of concentrated hydro- chloric acid. (b) Dissolve 0-2 g . of tryptophan in 100 ml. of concentrated, metal-free hydrochloric acid; use the reagent fresh and, if suitable, sensitised by 60 mg. of cysteine hydrochloride. T o 0.5 g . of gelatin powder, or the dry residue of an evaporated carbohydrate or sugar solution, add 3 ml. of solution (a) or ( b ) : Put the test tubes into boiling water for 20 mm. or 3 mh., respectively, soaking the gelatin for 10 min. in the reagents before heating A brown colour (melanin) develops with (a), and a violet colour with ( b ) , if carbohydrates or sugars are present. Results that have been obtained with gelatins of different kinds are noted.Carbo- hydrate solutions will indicate tryptophan, e.g., a solution of 1 g. of potato starch in 100ml. of ooncentrated hydrochloric acid. Raise the tem- perature of the solution to 70’ C., cool to room temperature, and use as a tryptophan (Voisenet) reagent. ( c ) Boiling monochloroacetic acid is a reagent for protein sugars. To 2 g. of mono- chloroacetic acid add 25 to 100 mg. of dry protein, and raise the temperature to 185OC. (b.p. of the acid). Reflux for 5 rnin., add 2 ml. of water, and carry out a colorimetric estimation. Hydroxy- proline or tryptophan condenses in boiling monochloroacetic acid with aldehydes to give melanin brown or violet colorations, respectively. If tryptophan and hydroxyproline are absent from the protein under test, add 6 to 10 mg.of one of these before the sugar test (this addition is un- necessary with gelatins). This test can also be used to detect tryptophan or hydroxyproline if only one of these is present. For example, to test gelatin for hydroxyproline, add 7 mg. of glucose and 10 to 20mg. of the gelatin powder to 2 g . of chloroacetic acid. Heat under reflux a t 1 8 5 O for 5 min., dilute with 2 ml. of water, and estimate colorimetrically . (4) .Anionic and cationic wetting agents and anionic and cationic “gelatins” as analytical reagents -(a) Reagent for alkaline earths-To 100ml. of 1 : 10,000 thionine solution add 2 ml. of B.D.H. Wanklyn’s volumetric soap solution and 75 ml. of 0.880 ammonia. To 2 ml. of this reagent add 1 drop of the test solution, e.g., tap water. If the solution contains an alkaline earth, the blue violet colour changes to red-violet.As the ammonia evaporates on keeping the solution, the reagent must not be too old. (b) Rfagent for soap-To 100 ml. of 1 : 10,000 thionine solution add 75 ml. of 0.880 ammonia. Traces of soap, fat or soap-forming fatty acid change the red-violet colour of the reagent to blue-violet. (c) “ Metal acid ” reagenf-To 100 ml. of 1 : 5,000 tropaeolin 00 solution (or thymol blue solution) add 2 ml. of 2 per cent. Sapamin KW 200 per cent. solution, and then 200 ml. of 0.5 N hydrochloric acid diluted with 100 ml. of distilkd water. Traces of sodium tungstate or salts’ of other metal acids turn the yellow reagent red. Cetyltrimethylammonium bromide (Cetavlon) can be used instead of Sapamin. (d) Preparation of cationic “gelatin ” and a cobalt- adsorbing reagent therefrom-Stir 30 g.of air-dried gelatin powder, practically metal-free. into 85 ml. of acetic anhydride ; raise the temperature within 20 min. to 125” while stirring. Add 150 ml. of water. Collect the acetylated gelatin on a Buchner funnel and wash several times with water. Dry the gelatin powder. To 100 ml. of 0.1 per cent. nitroso-R-salt solution add 7 g. of the cationic acetylated gelatin and 0.3 ml. of 5 N acetic acid. Heat to 60”. and stir occasionally. After 2 hrs., collect the stained gelatin powder on a Buchner funnel. Wash with water and dry. Use the powder as a sensitive cobalt-adsorbing reagent in the hot or boiling test solution (Schmidt, “ The Chemistry of the Amino Acids and Proteins,” Springfield and Baltimore, 1944, 720-778).(e) Preparation of an anionic gelatin, for the adsorption of basic dyes and ammines (cationic complexes) of silver, copper, nickel, cobalt. cadmium, and zinc from ammoniacd solsstions-Stir 30 g . of gelatin powder into a mixture30 ABSTRACTS OF CHEMICAL PAPERS of 10 ml. of 40 per cent. formaldehyde and 50 ml. of isopropyl alcohol. Heat to 8OoC., and maintain this temperature for 15 min. Decant the excess of solution. Add 100ml. of water to the tanned gelatin powder and collect it on a Buchner funnel. Wash several times with water and then with diluted ammonia (1 + 9). Wash again, filter, and dry. Example of a metal adsorption-Add to 3 mi. of 1 : 200,000 cobaltous nitrate solution 20mg. of anionic geiatin powder and 2 drops of 5 N ammonia solution.Heat and shake, centrifuge, wash, and centrifuge again. Then add 2 drops of 0.5 per cent. s-benzylthiuronium chloride solution and 2 ml. of water to the centrifuged gelatin powder containing the cobalt. Heat, add 2 drops of 5 N ammonia solution, and heat again to produce the charac- teristic mauve colour of cobalt on the gelatin grains. Adsorbed nickei is detected in the same way. The procedure is the same for adsorption of the other metals mentioned above. E. M. P. Analysis of Organoselenium Compounds. J. D. McCullough, T. W. Campbell, and N. J. Krilanovich (Ind. Eng. Chem., Anal. Ed., 1946, 18, 638-63Y)-Usual methods are either long or inaccurate. In testing available methods, the best results were obtained by a modification of the oxygen-combustion method at a glowing platinum surface’ (Niederl and Niederl, “ Micromethods of Quantitative Organic Analysis,” 2nd Ed., p.208, New York, John Wiley and Sons, 1942). Van ter Meulen’s method of determining selenium dioxide iodimetrically has been modified to eliminate errors due to the presence in a sample of hydro- chloric acid or of chlorine; the Iength of the method, and the need for constant attention rendered new procedures desirable. These now are (a) Flame combustion giving the selenium content directly. (b) Volumetric methods yielding the equivalent weight of the compound. Flame combustion method-This is based on a known method of halogen determination, but an oxygen flame is necessary for complete oxidation of the selenium to its dioxide.Apparatus and Proceduve-The apparatus used is shown approximately a quarter the actual size, ABCD being made of transparent quartz tubing, the dimensions of which are apparently not critical, and the chimney and absorption tube EFGH is of Pyrex glass with a T joint a t G. H is packed with grease-free, clean Pyrex glass-wool. The electric furnace, L, is contained in a 10 x 20cm. Pyrex electrolytic beaker, K, the heating unit consisting of 18 ft. of 22-gauge Chromel-A wire (1.0 ohm per foot) wound on a Transite frame, and energised by a variable transformer. Slight modifications are necessary to render the procedure applicable to fluid samples. A sample of 20 to 80mg. selenium content is workable depending on the thiosulphate normality, size of aliquots, etc., and is added a t A, either as a pellet, or weighed directly into a small platinum boat, and shaken to B.H.ydrogen is passed through D at 200ml. per min., and is ignited at C after expulsion of the original air. The oxygen supply is increased slowly to 100ml. per min., thus giving a stable flame. The furnace and chimney assemblies are brought into place, and a current of 1 litre of air per min. through the chimney is produced by applying suction a t J. Gauges are recommended for the three lines, but are not essential. The heater current is started, and raised to give a suitable rate of volatilisation of the sample as shown by the blue coloration of the otherwise colourless flame, which forms also an indicator of completeness of combustion.Most of the dioxide is deposited at F, but a significant quantity is drawn into H. In compounds where decom- position accompanies volatilisation, the dark non- volatile residue is slowly burned in the oxygen stream by gradually raising the temperature, the thermometer having been removed ; the decom- position may often be avoided by using a higher temperature, or higher rate of oxygen flow. Com- bustion is completed in 15 to 45 min., and the furnace is lowered to permit cooling, during which time suction is maintained. The deposit is rinsed from the chimney into a 250- or 500-ml. volumetric flask; H is rinsed by passing four 25-ml. portions of water slowly up anddown the glass wool, suction being applied alternately at G and J, and the rinsings added to the flask.Completeness of rinsing may be tested by adding the final water- rinsing to an acid solution of starch and potassium iodide, which should give no coloration. After filling the flask to the graduation mark, aliquot portions are titrated. Titration of selenious acid-The dissolved oxygen is expelled by gently boiling the solution, which is then ice-cooled, and kept air-free by the periodic addition of dry ice, or by the passage of carbon dioxide, or nitrogen, through the solution. These precautions are not essential, but give slightly more accurate results. Fifteen ml. of 2 per cent. starch solution, 10 ml. of 1.5 M potassium iodide, and 10 ml. of 6 N sulphuric acid are added in that order, with thorough mixing after each addition. The solution is then titrated at once with 0.05 N thiosulphate until the turbid brown solution turns clear red.1 ml. of 0.06 N Na&O, = 0.0870 mg. of Se.ORGANIC 31 Results and discussioti-The accuracy was tested on nine, carefully purified substances containing selenium with carbon and hydrogen, and oxygen, or nitrogen, or chlorine. Experimental and theoretical results are compared, and, for the samples analysed, the maximum deviation of 1 part in 204 occurred with p-nitrophenolselenocyanate C,H,N,O,Se of theoretical selenium content 34.77 per cent. Vohmetric metkods--Compounds containing selenium-halogen or selenium-oxygen bonds may be determined iodimetrically, since they react with potassium iodide solution to give the tri-iodide. The titration of diarylselenium dihalides has been previously described (J.D. McCullough, J . Amer. Chem. Soc., 1942, 64, 2672). Procedure for compounds reducible by potassium iodide-0-1 to 0.5 g. of the sample is weighed into 5ml. of carbon tetrachloride, 25 ml. of 0.3 M potassium iodide, and 2 ml. of 6 M sulphuric acid and, after thorough shaking, is titrated with standard thiosulphate in the presence of starch, added near the end-point. Values are given for eleven compounds in which the maximum discrepancy is 1 part in 262 for 4-bromodiphenyl- selenium dibromide, C,,H,BrSeBr,, of theoretical equivalent 2 3 6. Procedure for aryl disebnides-These may be titrated iodimetrically to the iodine monochloride end-point if the concentration of hydrochloric acid is kept a t 5.0' to 5.5' F. at the end-point. Errors of 0-5 to 1.0 per cent.are incurred by side reactions, but the complex reactions may be more simply represented by the equations :- KSe, 3- 6ICI-t ZRSeCI, +- 31,, and 21, -+ IO', + 6H' + 5C1'+ 3KO + SIC1 The iodine monochloride solution is prepared by titrating 1 ml. of 1-5 M potassium iodide in 60 ml. of 12 it$ hydrochloric acid, using 5 ml. of carbon tetrachloride for indicator purposes. When the carbon tetrachloride is just colourless, 25 ml. of 12 N hydrochloric acid and the weighed diselenide are added and, after shaking, the mixture is titrated with standard potassium iodate. M. E. D. Determination of Chlorine in 2 : 2'-Dihydroxy- 5 : 5'-dichlorodiphenylmethane. D. M. Jen- kins, I(. L. Waters, and G. D: Beal (Id. Eng. Chsm., Anal. Ed., 1946, 18, 609-610)-A rapid method for control purposes has been devised for the determination of chlorine in 2 : 2'-dihydroxy- 6 : 6'-dichlorodiphenylmethane (DDM or Compound G-4) depending upon oxidation of the compound with alkaline potassium permanganate, acidification, and reduction of the exceSs of permanganate by sodium nitrite, and the determination of the liberated chloride by the Volhard method, or by photometric measurement of the turbidity of silver chloride suspensions.General applicability of the method to organic compounds containing chlorine is not claimed, but it gives satisfactory results with DDM. Proceduve-Dissolve about 0.2 g . of DDM powder in 16 ml. of 10 per cent. sodium hydroxide solution in a 500-ml. Erlenmeyer flask, add 35 ml. of saturated potassium permanganate solution, or as much more as is necessary to maintain the purple colour of the permanganate. After introducing a few glass beads, boil the mixture gently for 10 min.Cool to room temperature, add 75 ml. of water and 10 ml. of concentrated nitric acid. Reduce the excess of potassium permanganate immediately by means of 10 per cent. sodium nitrite solution, added pre- ferably from a burette, ,add 26 ml. of 0.1 N silver nitrate, and titrate the excess with 0.1 N ammonium thiocyanate, 2 ml. of ferric alum solution being used as indicator. Make a blank determination with the reagents. The analysis of emulsions containing DDM, frequently used to impart water-repellency as well as mildew-proofness to fabrics, requires little change in the procedure described. The wax used in these emulsions readily separates on the surface of the liquid during oxidation, and does not interfere with the final titration.Owing to the small amount of DDM applied to fabrics, the chloride content of the oxidised extract cannot be conveniently titrated, but is readily determined by photometric methods, the acidity of the solution after addition of sodium nitrite being adjusted so that the silver chloride is main- tained in suspension. Extract 2 g. of the very finely cut fabric in a 150-ml. beaker three times with successive 50-ml. portions of 0.025 per cent. sodium carbonate solution by boiling gently for 6 min., and decant the hot extracts into a 200-ml. flask. Wash the extracted fabric twice with 16-ml. portions of the sodium carbonate solution, and dilute the combined extracts and washings to 200 ml.with sodium carbonate solution. Filter about 50 ml. and follow the oxidation procedure already described with these exceptions. Use a 25-ml. aliquot of the filtrate, reduce the volume of potassium permanganate solution to 25 ml., and omit the dilution with water after oxidation. After reduction of the excess of permanganate by means of acid and sodium nitrite, add a few drops of phenolphthalein indicator, and then enough 10 per cent. sodium hydroxide to produce a faint pink colour. Acidify with 10 ml. of diluted nitric acid (1 + 3), transfer the liquid to a 200-ml. flask, cool to room temperature, add 4 ml. of 0.1 N silver nitrate, dilute to the mark with water, and invert the flask several times. After 10 min., measure the turbidity with a suitable electrophotometer (the Fisher instrument was used in the investiga- tion), using a 625 filter, and determine the DDM content by reference to a s;tlandard curve.It is necessary to establish two blank '' values, v k . , an extract blank and a reagent blank. For the extract blank, pipette a 25-ml. aliquot of the filtrate into a 200-ml. flask, add 126 ml. of the sodium carbonate solution, 10 ml. of diluted nitric acid (1 + 3), and 4 ml. of 0.1 N silver nitrate, and dilute to the mark. Invert the flask several times and read after 10 min. This extract blank representing inorganic chlorides is often negligible. For the reagent blank, follow the same procedure, omitting the 25-ml. aliquot of the extract. Since the logarithm of the transmittance of silver chloride suspensions is an inverse and very nearly linear function of the turbidity, four determinations are adequate to establish the standard calibration curve.Establish the curve by first dissolving 600mg. of DDM in enough 2.6 per cent. sodium hydroxide solution to make 100 ml. of solution. Use suitable aliquots of this solution, containing 5 mg. of DDhf per ml., to cover the range of 2 to 15 mg. The procedure is then as described for the fabric extract. Solubility of Acetylene in Acetone. V. E. Brameld and M. T. Clark ( J . Suc. Chcm. Id., 1946, 65, 58-61)-A gravimetric method- for deter- mining the solubility of acetylene in acetone has been developed, and values have been determined at 6" intervals over the range 0" to 40" C. The A. 0. J.32 ABSTRACTS OF CHEMICAL PAPERS method is to saturate air-free acetone of B.S.609 foreign substances, e.g., salts, starch, and proteins. quality with acetylene until the whole system is in Methylol melamine allows of no reliable colour equilibrium under a total pressure above the solution reactions or, because of the stability of the triazole equal to one atmosphere plus the saturation vapour ring, Kjeldahl determination, the picrate is toosoluble pressure of acetone at the test temperature. Thus, to be used for a gravimetric determination, and pre- the solution is in equilibrium with acetylene at a cipitates with salts and alkali are unmanageable partial pressure of one atmosphere. From the gels. J. G. weights of vessel empty, plus acetone, and plus acetone and gas, the weight of acetylene dissolved by unit weight of acetone a t the test temperature is calculated. Certain corrections for the air in- evitably present in the acetylene are applied. Results obtained for the solubility coefficient, Sw, are : Sw, mg. of Temp., "C. &H,/g. of acetone 0 68.7 5 61.0 10 53.5 15 464 20 39.4 25 32.7 30 30.0 35 25.7 40 24.4 The equation Sw = 13100 -81.3, where T is the absolute temperature, holds over the temperature range -30" to 35" C. The following values were found for the solubility at different partial pressures of acetylene; S.= S',,/PAc where S', is the solubility under an acetylene p a h a l pressure of PA^ atmospheres. p--iw3) Test temperature 30" C. Acetylene partial pressure, atm. 0.742 0.7 60 0.805 0.835 0.897 0-905 0.982 0.999 1.047 1-054 1-164 S',, mg./g. 22.6 23.2 24.4 25.0 26.5 27.2 29.2 29.7 31.0 31.2 34.0 E. M. P. Analysis of Dilute Melamine Resin Solutions. B. Ivarsson and B. Steenberg (Svensk Pupper- stdn., 1946, 49, 1; through Tech. Bull., 1946, 23, lZ)-For routine work, a known wt. of the sample, as supplied for use in paper, is diluted to 35ml., 0.1 N sodium hydroxide is added, and after vigorous agitation, the resulting turbidity is evaluated in a Pulfrich photometer. The method must be cali- brated with known weights of resin, under constant conditions, of which the most important are the volume of sodium hydroxide added, the time elapsing after its addition, the concentration and age of the original and diluted solutions, and the presence of

ISSN:0003-2654    

DOI:10.1039/AN9477200028

出版商:RSC    

年代:1947

数据来源: RSC