摘要:

REVIEWS 51 EAUX DOUCES ET EAUX MINERALES. By F. DIENERT. Paris : Ch. BQranger. 1912. This volume is one of the series of 6 4 Manuels Pratiques d’Analyses Chimiques,” published under the direction of MM. Bordas and Roux. Of these nine or ten have already appeared, and the complete series will comprise twenty-four volumes. The series is intended more especially for the use of analysts and experts attached to ofticial laboratories in France, and the volume under review is written by the chief of the (( Service de la Surveillance des Eaux d’Alimentation de Paris.” About half of the book is devoted to the methods of analysis, chemical, physical, and bacterio- logical, of soft ” and mineral waters, and tables are given showing the composition of almost all the better-known Continental mineral waters.The analytical methods given are mainly confined to those which have received ‘‘ official ” sanction in France ; and in several sections, notably in that dealing with the estimation of nitrates, no mention is made of several well-known methods which are commonly employed by water analysts. Such analytical methods as are given are, for the most part, clearly described, and the book would appear to be admirably suited to the purpose for which it is intended; but from the point of view of the water analyst, who is called upon to express an opinion as to the quality of a water-supply, and to suggest the most efficient means of purification, it is to be regretted that no actual figures are given of the results of analysis of waters of different types, which would illustrate the principles upon which such an opinion should be based.More detailed criticism of and comparisons between the different analytical methods employed, and references to recent work on water purification, such as is to be found in the annual reports of the Metropolitan Water Board, would have materially enhanced the value of what is otherwise 8 useful book.The chapters on investigation in the ‘( field,” sampling, etc., contain some interesting and suggestive details, many of which are apt to be overlooked when collecting samples for analysis. The volume concludes with an appendix, containing information as to the more important legislation enacted in respect of the sale of mineral waters in France. G. W. MONIER-WILLIAMS.Pp. 354 + Table of Contents. Price 6s. INSTITUTE OF CHEMISTRY OF GREAT BRITAIN AND IRELAND. FINAL EXAMINATION FOR THE ASSOCIATESHIP IN THE BRANCH OF BIOLOGICAL CHEMISTRY. OCTOBER 14 TO 18, 1912. The following candidates passed : Robert Philip Keith, Eric Richards, and Frederic Robinson.54 SAUL: DELICATE COLOUR REACTIONS OF GOLD SALTS those who were privileged to number him among their personal friends, his loss seems irreparable. He was ever one of the kindliest of men, always looking out to lend a helping hand in a quiet, unobtrusive way, either by personal service or finan- cially in cases of need. Even those who were intimately associated with him never knew how many and varied were his activities in the interests of others. He will be sadly missed. F. W. HARBORD.

ISSN:0003-2654    

DOI:10.1039/AN9133800053

出版商:RSC    

年代:1913

数据来源: RSC

摘要:

54 SAUL: DELICATE COLOUR REACTIONS OF GOLD SALTS PROCEEDINGS OF THE SOCIETY OF PUBLIC ANALYSTS AND OTHER ANALYTICAL CHEMISTS. DELICATE COLOUR REACTIONS OF GOLD SALTS. BY J. E. SAUL, F.I.C. IT is found that dilute solutions of certain aromatic reducing agents added to solutions of gold salts result in the formation of coloured colloidal solutions of gold. Quinol, pyrogallol, gallotannic acid, p-oxyphenylaminoacetic acid (glycin), and salts of phenylhydrazine, 1 : 2 : 4 diaminophenol (amidol), the monornethyl derivatives of m- and p- (metol), and o-aminophenol, associated with quinol in (ortol), and m-phenylenediamine, may be mentioned amongst others as producing these reactions, If one volume of a 0.1 per cent.solution of any of the above compounds is added to ten volumes of a solution containing 0,002 per cent.of auric chloride, a violet- coloured colloidal solution of gold is produced in the course of a couple of minutes. The colours vary according to the reagents used and the strength of the solution@. I n the case of gallotannic acid the colloidal solution in that dilution is rose-coloured, and the tint takes a longer time to develop.The colours are generally very beautiful and effective, in some cases much more than in others. The colours yielded with (metol) and quinol, for example, are particularly fine. In studying these reactions, the writer has observed that p-phenylenediamine acte abnormally, and, as the resulting reaction is of extraordinary delicacy, he ventures to suggest its use as a test for traces of gold salts.In this case a dark yellowish-green solution results, which, after the lapse of some time, undergoes further changes. In using the test it is suggested that a weaker solution of the gold salt be employed. One volume of a 0.1 per cent. solution of p-phenylenediamine hydrochloride should be added to ten volumes of a solution containing 0.0005 per cent. of the gold chloride. A distinct greenish-yellow coloration results, and this is still quite visible in a solution containing only 0.0001 per cent. of the gold salt. The reaction appears to transcend in delicacy any of the violet reactions before referred to, and it may be found useful occasionally in analysis.

ISSN:0003-2654    

DOI:10.1039/AN9133800054

出版商:RSC    

年代:1913

数据来源: RSC

摘要:

54 SAUL: DELICATE COLOUR REACTIONS OF GOLD SALTS PROCEEDINGS OF THE SOCIETY OF PUBLIC ANALYSTS AND OTHER ANALYTICAL CHEMISTS. DELICATE COLOUR REACTIONS OF GOLD SALTS. BY J. E. SAUL, F.I.C. IT is found that dilute solutions of certain aromatic reducing agents added to solutions of gold salts result in the formation of coloured colloidal solutions of gold. Quinol, pyrogallol, gallotannic acid, p-oxyphenylaminoacetic acid (glycin), and salts of phenylhydrazine, 1 : 2 : 4 diaminophenol (amidol), the monornethyl derivatives of m- and p- (metol), and o-aminophenol, associated with quinol in (ortol), and m-phenylenediamine, may be mentioned amongst others as producing these reactions, If one volume of a 0.1 per cent.solution of any of the above compounds is added to ten volumes of a solution containing 0,002 per cent.of auric chloride, a violet- coloured colloidal solution of gold is produced in the course of a couple of minutes. The colours vary according to the reagents used and the strength of the solution@. I n the case of gallotannic acid the colloidal solution in that dilution is rose-coloured, and the tint takes a longer time to develop.The colours are generally very beautiful and effective, in some cases much more than in others. The colours yielded with (metol) and quinol, for example, are particularly fine. In studying these reactions, the writer has observed that p-phenylenediamine acte abnormally, and, as the resulting reaction is of extraordinary delicacy, he ventures to suggest its use as a test for traces of gold salts.In this case a dark yellowish-green solution results, which, after the lapse of some time, undergoes further changes. In using the test it is suggested that a weaker solution of the gold salt be employed. One volume of a 0.1 per cent. solution of p-phenylenediamine hydrochloride should be added to ten volumes of a solution containing 0.0005 per cent. of the gold chloride.A distinct greenish-yellow coloration results, and this is still quite visible in a solution containing only 0.0001 per cent. of the gold salt. The reaction appears to transcend in delicacy any of the violet reactions before referred to, and it may be found useful occasionally in analysis.54 SAUL: DELICATE COLOUR REACTIONS OF GOLD SALTS PROCEEDINGS OF THE SOCIETY OF PUBLIC ANALYSTS AND OTHER ANALYTICAL CHEMISTS.DELICATE COLOUR REACTIONS OF GOLD SALTS. BY J. E. SAUL, F.I.C. IT is found that dilute solutions of certain aromatic reducing agents added to solutions of gold salts result in the formation of coloured colloidal solutions of gold. Quinol, pyrogallol, gallotannic acid, p-oxyphenylaminoacetic acid (glycin), and salts of phenylhydrazine, 1 : 2 : 4 diaminophenol (amidol), the monornethyl derivatives of m- and p- (metol), and o-aminophenol, associated with quinol in (ortol), and m-phenylenediamine, may be mentioned amongst others as producing these reactions, If one volume of a 0.1 per cent.solution of any of the above compounds is added to ten volumes of a solution containing 0,002 per cent. of auric chloride, a violet- coloured colloidal solution of gold is produced in the course of a couple of minutes.The colours vary according to the reagents used and the strength of the solution@. I n the case of gallotannic acid the colloidal solution in that dilution is rose-coloured, and the tint takes a longer time to develop. The colours are generally very beautiful and effective, in some cases much more than in others.The colours yielded with (metol) and quinol, for example, are particularly fine. In studying these reactions, the writer has observed that p-phenylenediamine acte abnormally, and, as the resulting reaction is of extraordinary delicacy, he ventures to suggest its use as a test for traces of gold salts. In this case a dark yellowish-green solution results, which, after the lapse of some time, undergoes further changes. In using the test it is suggested that a weaker solution of the gold salt be employed.One volume of a 0.1 per cent. solution of p-phenylenediamine hydrochloride should be added to ten volumes of a solution containing 0.0005 per cent. of the gold chloride. A distinct greenish-yellow coloration results, and this is still quite visible in a solution containing only 0.0001 per cent.of the gold salt. The reaction appears to transcend in delicacy any of the violet reactions before referred to, and it may be found useful occasionally in analysis.54 SAUL: DELICATE COLOUR REACTIONS OF GOLD SALTS PROCEEDINGS OF THE SOCIETY OF PUBLIC ANALYSTS AND OTHER ANALYTICAL CHEMISTS. DELICATE COLOUR REACTIONS OF GOLD SALTS.BY J. E. SAUL, F.I.C. IT is found that dilute solutions of certain aromatic reducing agents added to solutions of gold salts result in the formation of coloured colloidal solutions of gold. Quinol, pyrogallol, gallotannic acid, p-oxyphenylaminoacetic acid (glycin), and salts of phenylhydrazine, 1 : 2 : 4 diaminophenol (amidol), the monornethyl derivatives of m- and p- (metol), and o-aminophenol, associated with quinol in (ortol), and m-phenylenediamine, may be mentioned amongst others as producing these reactions, If one volume of a 0.1 per cent.solution of any of the above compounds is added to ten volumes of a solution containing 0,002 per cent. of auric chloride, a violet- coloured colloidal solution of gold is produced in the course of a couple of minutes.The colours vary according to the reagents used and the strength of the solution@. I n the case of gallotannic acid the colloidal solution in that dilution is rose-coloured, and the tint takes a longer time to develop. The colours are generally very beautiful and effective, in some cases much more than in others. The colours yielded with (metol) and quinol, for example, are particularly fine.In studying these reactions, the writer has observed that p-phenylenediamine acte abnormally, and, as the resulting reaction is of extraordinary delicacy, he ventures to suggest its use as a test for traces of gold salts. In this case a dark yellowish-green solution results, which, after the lapse of some time, undergoes further changes. In using the test it is suggested that a weaker solution of the gold salt be employed.One volume of a 0.1 per cent. solution of p-phenylenediamine hydrochloride should be added to ten volumes of a solution containing 0.0005 per cent. of the gold chloride. A distinct greenish-yellow coloration results, and this is still quite visible in a solution containing only 0.0001 per cent. of the gold salt.The reaction appears to transcend in delicacy any of the violet reactions before referred to, and it may be found useful occasionally in analysis.54 SAUL: DELICATE COLOUR REACTIONS OF GOLD SALTS PROCEEDINGS OF THE SOCIETY OF PUBLIC ANALYSTS AND OTHER ANALYTICAL CHEMISTS. DELICATE COLOUR REACTIONS OF GOLD SALTS. BY J. E. SAUL, F.I.C. IT is found that dilute solutions of certain aromatic reducing agents added to solutions of gold salts result in the formation of coloured colloidal solutions of gold.Quinol, pyrogallol, gallotannic acid, p-oxyphenylaminoacetic acid (glycin), and salts of phenylhydrazine, 1 : 2 : 4 diaminophenol (amidol), the monornethyl derivatives of m- and p- (metol), and o-aminophenol, associated with quinol in (ortol), and m-phenylenediamine, may be mentioned amongst others as producing these reactions, If one volume of a 0.1 per cent.solution of any of the above compounds is added to ten volumes of a solution containing 0,002 per cent. of auric chloride, a violet- coloured colloidal solution of gold is produced in the course of a couple of minutes. The colours vary according to the reagents used and the strength of the solution@.I n the case of gallotannic acid the colloidal solution in that dilution is rose-coloured, and the tint takes a longer time to develop. The colours are generally very beautiful and effective, in some cases much more than in others. The colours yielded with (metol) and quinol, for example, are particularly fine. In studying these reactions, the writer has observed that p-phenylenediamine acte abnormally, and, as the resulting reaction is of extraordinary delicacy, he ventures to suggest its use as a test for traces of gold salts.In this case a dark yellowish-green solution results, which, after the lapse of some time, undergoes further changes. In using the test it is suggested that a weaker solution of the gold salt be employed.One volume of a 0.1 per cent. solution of p-phenylenediamine hydrochloride should be added to ten volumes of a solution containing 0.0005 per cent. of the gold chloride. A distinct greenish-yellow coloration results, and this is still quite visible in a solution containing only 0.0001 per cent. of the gold salt. The reaction appears to transcend in delicacy any of the violet reactions before referred to, and it may be found useful occasionally in analysis.54 SAUL: DELICATE COLOUR REACTIONS OF GOLD SALTS PROCEEDINGS OF THE SOCIETY OF PUBLIC ANALYSTS AND OTHER ANALYTICAL CHEMISTS.DELICATE COLOUR REACTIONS OF GOLD SALTS. BY J. E. SAUL, F.I.C. IT is found that dilute solutions of certain aromatic reducing agents added to solutions of gold salts result in the formation of coloured colloidal solutions of gold.Quinol, pyrogallol, gallotannic acid, p-oxyphenylaminoacetic acid (glycin), and salts of phenylhydrazine, 1 : 2 : 4 diaminophenol (amidol), the monornethyl derivatives of m- and p- (metol), and o-aminophenol, associated with quinol in (ortol), and m-phenylenediamine, may be mentioned amongst others as producing these reactions, If one volume of a 0.1 per cent.solution of any of the above compounds is added to ten volumes of a solution containing 0,002 per cent. of auric chloride, a violet- coloured colloidal solution of gold is produced in the course of a couple of minutes. The colours vary according to the reagents used and the strength of the solution@. I n the case of gallotannic acid the colloidal solution in that dilution is rose-coloured, and the tint takes a longer time to develop.The colours are generally very beautiful and effective, in some cases much more than in others. The colours yielded with (metol) and quinol, for example, are particularly fine. In studying these reactions, the writer has observed that p-phenylenediamine acte abnormally, and, as the resulting reaction is of extraordinary delicacy, he ventures to suggest its use as a test for traces of gold salts.In this case a dark yellowish-green solution results, which, after the lapse of some time, undergoes further changes. In using the test it is suggested that a weaker solution of the gold salt be employed. One volume of a 0.1 per cent. solution of p-phenylenediamine hydrochloride should be added to ten volumes of a solution containing 0.0005 per cent.of the gold chloride. A distinct greenish-yellow coloration results, and this is still quite visible in a solution containing only 0.0001 per cent. of the gold salt. The reaction appears to transcend in delicacy any of the violet reactions before referred to, and it may be found useful occasionally in analysis.54 SAUL: DELICATE COLOUR REACTIONS OF GOLD SALTS PROCEEDINGS OF THE SOCIETY OF PUBLIC ANALYSTS AND OTHER ANALYTICAL CHEMISTS.DELICATE COLOUR REACTIONS OF GOLD SALTS. BY J. E. SAUL, F.I.C. IT is found that dilute solutions of certain aromatic reducing agents added to solutions of gold salts result in the formation of coloured colloidal solutions of gold. Quinol, pyrogallol, gallotannic acid, p-oxyphenylaminoacetic acid (glycin), and salts of phenylhydrazine, 1 : 2 : 4 diaminophenol (amidol), the monornethyl derivatives of m- and p- (metol), and o-aminophenol, associated with quinol in (ortol), and m-phenylenediamine, may be mentioned amongst others as producing these reactions, If one volume of a 0.1 per cent. solution of any of the above compounds is added to ten volumes of a solution containing 0,002 per cent.of auric chloride, a violet- coloured colloidal solution of gold is produced in the course of a couple of minutes. The colours vary according to the reagents used and the strength of the solution@. I n the case of gallotannic acid the colloidal solution in that dilution is rose-coloured, and the tint takes a longer time to develop.The colours are generally very beautiful and effective, in some cases much more than in others. The colours yielded with (metol) and quinol, for example, are particularly fine. In studying these reactions, the writer has observed that p-phenylenediamine acte abnormally, and, as the resulting reaction is of extraordinary delicacy, he ventures to suggest its use as a test for traces of gold salts.In this case a dark yellowish-green solution results, which, after the lapse of some time, undergoes further changes. In using the test it is suggested that a weaker solution of the gold salt be employed. One volume of a 0.1 per cent. solution of p-phenylenediamine hydrochloride should be added to ten volumes of a solution containing 0.0005 per cent.of the gold chloride. A distinct greenish-yellow coloration results, and this is still quite visible in a solution containing only 0.0001 per cent. of the gold salt. The reaction appears to transcend in delicacy any of the violet reactions before referred to, and it may be found useful occasionally in analysis.FOOD AND DRUGS ANALYSIS 61 (caffeine, theobromine, etc.) is based upon the fact that they are readily oxidised to carbylamine, which may be recognised by its characteristic odour.A small quantity of the substance under examination is mixed with a few drops of a concentrated solu- tion of potassium hydroxide, followed by a few drops of a saturated solution of potas- sium permanganate, and the mixture gently heated. By mean8 of this test it was found that ordinary commercial cocoa butter contains traces of xanthine bases.Estimation of Xanthine Bases.--Ten grms. of, e.g., cocoa or chocolate are boiled for thirty minutes with 150 C.C. of water and 50 C.C. of sulphuric acid, and the liquid then diluted to 500 c.c., heated on the water-bath, and filtered while hot. The filtrate is cooled, and 250 C.C. of it neutralised with magnesium oxide and evaporated to about 80 c.c., after which it is transferred to a special form of Soxhlet’s extractor, and extracted for two to three hours with boiling carbon tetrachloride.Or it may be shaken in a separating funnel with three times its volume of carbon tetrachloride. This solvent extracts the caffeine and a little of the theobromine simultaneously with the fat, whilst the bulk of the theobromine remains in the aqueous layer. The carbon tetrachloride is evaporated after the addition of a little paraffin wax, and the residue repeatedly treated with small quantities (25 to 30 C.C. at a time) of boiling water slightly acidified with sulphuric acid. The aqueous extracts are filtered and added to the original aqueous layer, and the whole mixed with 5 grms. of magnesium oxide and evaporated to dryness. The residual masB is then powdered and extracted four or five times with successive portions (100 c.c.) of boiling chloroform, for ten minutes each time. If the extracted theobromine and caffeine are not perfectly white and well crystsllised, they are purified by treating their aqueous solution with 1 per cent. of cold potassium permanganate solution, and again extracting them with chloroform in a separating funnel. C. A. M.

ISSN:0003-2654    

DOI:10.1039/AN9133800055

出版商:RSC    

年代:1913

数据来源: RSC

摘要:

FOOD AND DRUGS ANALYSIS 61 BACTERIOLOGICAL, PHYSIOLOGICAL, ETC. Action of ‘‘ Activated ” Aluminium on Alkaloid Extracts and its Employ- ment in Toxicology. E. Kohn-Abrest. (Comptes rend., 1912, 155, 1179-1181.)- In many cases ‘‘ activated ” aluminium may be substituted with advantage for basic lead acetate or animal charcoal for the clarification of organic liquids. Thin sheets of aluminium foil are immersed for three minutes in a 1 per cent.solution of mercuric cfhoride. In presence of water this “ activated ” foil causes a gentle evolution of hydrogen, the decolorising and preservative action of which is supplemented by the absorptive affinity of the aluminium oxide produced. Such foil has been used with much success in the treatment of the aqueous-alcoholic extracts of putrid or putrifi- able animal organs for the toxicological separation of alkaloids.A series of experi- ments was first performed with solutions of the pure alkaloids in a, mixture of 80 C.C. of alcohol, 20 C.C. of water, and 1 grm. of tartaric acid, 0.1 grm. of alkaloid being added in each case. These solutions were each treated for twenty-four hours with a, piece of foil weighing 3 to 4 grms.: the alkaloids were then estimated by approved methods. In the case of morphine, heroine, narcotine, codeine, atropine, brucine, narceine, and antipyrine, the quantity of alkaloid recovered was 90 to 100 per cent. ; in the case of caffeine and veratrine, 80 to 85 per cent. ; and with strychnine, quinine,FOOD AND DRUGS ANALYSIS 61 BACTERIOLOGICAL, PHYSIOLOGICAL, ETC. Action of ‘‘ Activated ” Aluminium on Alkaloid Extracts and its Employ- ment in Toxicology.E. Kohn-Abrest. (Comptes rend., 1912, 155, 1179-1181.)- In many cases ‘‘ activated ” aluminium may be substituted with advantage for basic lead acetate or animal charcoal for the clarification of organic liquids. Thin sheets of aluminium foil are immersed for three minutes in a 1 per cent.solution of mercuric cfhoride. In presence of water this “ activated ” foil causes a gentle evolution of hydrogen, the decolorising and preservative action of which is supplemented by the absorptive affinity of the aluminium oxide produced. Such foil has been used with much success in the treatment of the aqueous-alcoholic extracts of putrid or putrifi- able animal organs for the toxicological separation of alkaloids.A series of experi- ments was first performed with solutions of the pure alkaloids in a, mixture of 80 C.C. of alcohol, 20 C.C. of water, and 1 grm. of tartaric acid, 0.1 grm. of alkaloid being added in each case. These solutions were each treated for twenty-four hours with a, piece of foil weighing 3 to 4 grms. : the alkaloids were then estimated by approved methods. In the case of morphine, heroine, narcotine, codeine, atropine, brucine, narceine, and antipyrine, the quantity of alkaloid recovered was 90 to 100 per cent.; in the case of caffeine and veratrine, 80 to 85 per cent. ; and with strychnine, quinine,FOOD AND DRUGS ANALYSIS 61 BACTERIOLOGICAL, PHYSIOLOGICAL, ETC. Action of ‘‘ Activated ” Aluminium on Alkaloid Extracts and its Employ- ment in Toxicology.E. Kohn-Abrest. (Comptes rend., 1912, 155, 1179-1181.)- In many cases ‘‘ activated ” aluminium may be substituted with advantage for basic lead acetate or animal charcoal for the clarification of organic liquids. Thin sheets of aluminium foil are immersed for three minutes in a 1 per cent. solution of mercuric cfhoride.In presence of water this “ activated ” foil causes a gentle evolution of hydrogen, the decolorising and preservative action of which is supplemented by the absorptive affinity of the aluminium oxide produced. Such foil has been used with much success in the treatment of the aqueous-alcoholic extracts of putrid or putrifi- able animal organs for the toxicological separation of alkaloids.A series of experi- ments was first performed with solutions of the pure alkaloids in a, mixture of 80 C.C. of alcohol, 20 C.C. of water, and 1 grm. of tartaric acid, 0.1 grm. of alkaloid being added in each case. These solutions were each treated for twenty-four hours with a, piece of foil weighing 3 to 4 grms. : the alkaloids were then estimated by approved methods.In the case of morphine, heroine, narcotine, codeine, atropine, brucine, narceine, and antipyrine, the quantity of alkaloid recovered was 90 to 100 per cent. ; in the case of caffeine and veratrine, 80 to 85 per cent. ; and with strychnine, quinine,FOOD AND DRUGS ANALYSIS 61 BACTERIOLOGICAL, PHYSIOLOGICAL, ETC. Action of ‘‘ Activated ” Aluminium on Alkaloid Extracts and its Employ- ment in Toxicology.E. Kohn-Abrest. (Comptes rend., 1912, 155, 1179-1181.)- In many cases ‘‘ activated ” aluminium may be substituted with advantage for basic lead acetate or animal charcoal for the clarification of organic liquids. Thin sheets of aluminium foil are immersed for three minutes in a 1 per cent. solution of mercuric cfhoride. In presence of water this “ activated ” foil causes a gentle evolution of hydrogen, the decolorising and preservative action of which is supplemented by the absorptive affinity of the aluminium oxide produced.Such foil has been used with much success in the treatment of the aqueous-alcoholic extracts of putrid or putrifi- able animal organs for the toxicological separation of alkaloids. A series of experi- ments was first performed with solutions of the pure alkaloids in a, mixture of 80 C.C. of alcohol, 20 C.C.of water, and 1 grm. of tartaric acid, 0.1 grm. of alkaloid being added in each case. These solutions were each treated for twenty-four hours with a, piece of foil weighing 3 to 4 grms. : the alkaloids were then estimated by approved methods. In the case of morphine, heroine, narcotine, codeine, atropine, brucine, narceine, and antipyrine, the quantity of alkaloid recovered was 90 to 100 per cent.; in the case of caffeine and veratrine, 80 to 85 per cent. ; and with strychnine, quinine,BACTERIOLOGICAL, PHYSIOLOGICAL, ETC. 65 quantities of phenylhydrazine hydrochloride and sodium acetate must be used. For the detection of pentoses in urine which is free from sugar, it; is advisable to add about 1 per cent.of dextrose before proceeding with the test. w. P. s. Estimation of Sugar (Dextrose) in Urine. K. K. Jarvinen. (Zeitsch. anal. Chem., 1913, 52, 14-15.1-The colorimetric method described depends on the production of a black colour when dextrose is heated with AlmBn-Nylander’s reagent (2 grms. of bismuth subnitrate and 4 grms.of Rochelle salt dissolved in 100 grms. of 8 per cent. sodium hydroxide solution). Ten C.C. of the urine (diluted with twice its volume of water if much sugar is present) are placed in a test-tube, and 0-5 C.C. of the reagent is added; other test-tubes are prepared, each containing 10 C.C. of diluted sugar-free urine and 0.5 C.C. of the reagent, and to these tubes are added quantities (0.1 c.c., 0.2 c.c., 0.5 c.c., 1 c.c., etc., respectively) of a, 1 per cent.dextrose solution. The contents of the tubes are then diluted to a, volume of 12.5 c.c., and they are heated in a boiling water-bath. The coloration given by the sample of urine is then compared with that obtained in the other tubes. w. P. s. Estimation of Uric Acid in Urine. F. Herles. (Eighth Int.Cong. App. Chem., 1912, vol. 19, 141-144.)-The method proposed consists in precipitating the uric acid as ammonium urate, and titrating the latter with a mineral acid. One hundred C.C. of the urine are treated in a beaker with 36 grms. of powdered ammonium chloride, the mixture being stirred until the salt has dissolved. After the lapse of thirty minutes the precipitate is collected on a filter and washed three times with saturated ammonium chloride ; the filter and precipitate are then placed in the beaker, heated to boiling with about 50 C.C.of water, and the solution is titrated with & sulphuric acid, 2 drops of methyl-orange solution being added as indicator. It is advisable to add a slight excess of the acid, and to titrate this excess with & alkali solution. One C.C. of & acid corresponds with 0.0168 grm. of uric acid. If the urine under examination is not clear, 100 C.C. of it are warmed and treated with sodium hydroxide solution until alkaline to phenolphthaleln. The alkaline solution is then partially evaporated, transferred to a 100 C.C. flask, cooled, diluted to 100 c.c., and filtered. Fifty C.C. of the filtrate are used for the estimation of the uric acid. Results of experiments with pure uric acid show that the method is accurate. w. P. s.

ISSN:0003-2654    

DOI:10.1039/AN9133800061

出版商:RSC    

年代:1913

数据来源: RSC

摘要:

INORGANIC ANALYSIS 75 wheat starch requires twenty-four minutes ; any ungelatinised starch granules observ-able in such a mixture after seven minutes’ heating indicate the probable presence of wheatmeal. w. P. s

ISSN:0003-2654    

DOI:10.1039/AN9133800065

出版商:RSC    

年代:1913

数据来源: RSC

摘要:

INORGANIC ANALYSIS 75 INORGANIC ANALYSIS. (Zeitsch. anal. Chem., 1913, 52, 28-31.)-A definite volume of the barium sulphide solution is treated with an excess of standardised lead nitrate solution, the mixture is rendered slightly acid with acetic acid, and after the lapse of a short time the lead sulphide is separated by filtration and washed with cold water. The excess of lead in the filtrate and wash-water is then titrated with ammonium molybdate solution, as Method for the Analysis of Barium Sulphide.J. F. Sacher. described previously by the author (cf. ANALYST, 1910, 35, 79). w. P. s. Estimation of Small Quantities of Carbon Monoxide. 0. Brunck. (Zeitsch. angew. Chenz., 1912, 25, 2479-2481.)-The method described depends on the reduction of palladium chloride to metallic palladium by the action of carbon monoxide.The gas in which the carbon monoxide is to be estimated is collected in a flask of from 0.5 to 1 litre capacity; this flask is fitted with a rubber stopper having two holes, which are closed by means of two short pieces of glass rod, and the actual capacity of the flask is determined accurately. After the flask has been filled with the gas, about 20 C.C.of a sodium-palladous chloride solution (containing a quantity of the salt per litre equivalent to about 4.7 grms. of palladium) and 10 C.C. of a 5 per cent. sodium acetate solution are added successively by means of a pipette the stem of which passes through one of the holes in the stopper ; while the solutions are being added the glass-rod in the other hole is loosened slightly.The glass rods are af once reinserted in the stopper, and the flask is agitated gently for about thirty minutes. Should the liquid in the flask remain quite clear, carbon monoxide is not present; but if metallic palladium is precipitated it is collected on a filter, washed with hot water, incinerated, and the metal heated in a current of hydrogen before being weighed.One grm. of palladium is equivalent to 0.2624 grm. or 210 C.C. (N.T.P.) of carbon monoxide. I t has already been proposed to absorb carbon monoxide in cuprous chloride solution, and to then add palladous chloride, but Winkler has shown that the metallic palladium precipitated under these conditions always retains copper, even after washing with hydrochloric acid and ammonia.w. P. s. Estimation of Copper by Means of Sodium Hypophosphite. R. Windiseh. (Zeitsclz. anal. Chem., 1913, 52, l-I3.)-The method described by Dallimore (cf. ANALYST, 1909, 34, 452) was found to yield accurate results; pure copper sulphate yielded 31.60 per cent. of cupric oxide against 31.78 per cent. required by theory and 31.62 found by the electrolytic method. The author prefers to use sodium hypophosphite in place of hypophosphorus acid as recommended by Dallimore.A quantity of about 100 grms. of the copper salt under examination are dissolved in water, and diluted to 1 litre; 50 C.C. of this solution are acidified with 3 C.C. of sulphuric acid, 20 C.C. of a 20 per cent. sodium hypophosphite solution are76 ABSTRACTS OF CHEMICAL PAPERS added, and the mixture is heated to boiling for ten minutes, The reduced copper is then collected on a filter, dried, ignited to oxide, and weighed.The presence of considerable amounts of iron salts does not affect the accuracy of the results obtained by the method. w. P. s. Analysis of Ferro-Silicon. S. Camilla and C. Pertusi. (Ann. Lab. C h h . Centr. delle Gabelle, 1912, 6, 627-630.)-Since the impurities in commercial ferro- silicon (aluminium, manganese, phosphorus, sulphur, and carbides) never exceed 2 per cent., the following rapid method of analysis will give results sufliciently accurate for general purposes : From 0.4 to 0.5 grm.of the finely powdered sample is treated in a platinum crucible with 20 to 30 C.C. of hydrofluoric acid, followed by a few drops of concentrated nitric acid.As soon as a clear solution is obtained, a few C.C. of dilute sulphuric acid are added, the liquid evaporated to dryness, and the residue ignited in a muffle until constant in weight, and weighed as ferric oxide. The silicon is then found by difference. C. A. M. Influence of Colloids on the Electrolytic Separation of Lead. H. Freundlich and J.Fiseher. (Zeitsch. Elektrochern., 1912, 18, 885-891 ; through Chew. Zentralbl., 1912, II., 1885.)-It is known that the cathodic deposition of certain metals, particularly lead, is assisted by the presence of certain foreign matters of colloidal nature. The deposition itself is probably a complex process, and consists of discharging, dehydration, and crystallisation. I t would, then, appear that the action of the colloid consists in a retardation of the crystallisation velocity, as has recently been suggested by Marc.In that case a parallelism should exist between the protective action of the colloid, for instance, towards colloidal gold solution and its power of facilitating the cathodic deposition of lead. The author has tested this hypothesis experimentally. To solutions of lead in hydrofluosilicic acid and perchloric acid there were added during electrolysis increasing quantities of gelatin, dextrin, and a few other organic colloids, and the quantities necessary for the production of a smooth, adherent deposit of lead were estimated.Then the protective action of the same colloids in gold solutions was tested, and the quantities were estimated which were required to change the red solution into violet.No definite parallelism which would confirm the above hypothesis could be observed. Nevertheless, the investigations indicated that the colloids are adsorbed by nascent germs of the metal, that the crystallisation velocity is thereby retarded, and the compactness of the deposit improved; also in the precipitation of the lead by zinc a similar influence of colloids was established as in the case of electrolysis.J. F. B. Calorimetric Detection and Estimation of Magnesium Oxide in Mag- nesium Carbonate, Asbestos Mixtures, etc. V. Fortini. (Ann. Lab. Chim. Centr. delle Gabelle, 1912, 6, 509-512.)-Magnesium oxide (or other oxide of an alkali earth) may be estimated in carbonates or mixtures containing asbestos, glass wool, etc., by the rise of temperature produced on treatment with dilute hydrochloric acid, Twenty-five C.C.of the acid (sp. gr. 1.19 diluted with an equal quantity of water)INORGANIC ANALYSIS 77 are placed in a small Dewar's vacuum tube, the temperature taken, a weighed quantity (0.5 grm. or 1 grm.) of the substance introduced, the mixture stirred with the thermometer, and the rise in temperature noted.The increase will be propor- tional to the quantity of magnesium oxide, etc., in the sample, provided that the same calorimeter and method of working be used. The apparatus is first standard- ised upon pure magnesium oxide and calcium oxide. For example, in the author's experiments the following results were obtained : Magnesium oxide (grms.) ... 1.0 0.5 0.4 0.3 0.2 0.1 Rise in temperature (" C.) 37.0 19.0 13.9 11.3 7.3 3.7 Calcium oxide (grms.) ...1.0 0.5 0.4 0.3 0.2 0-1 Rise in temperature (" C.) 36-8 18-8 14.8 11.4 7.4 3.7 No rise of temperature was obtained with pure neutral magnesium carbonate or calcium carbonate, but ordinary commercial magnesium carbonate showed a rise of 1' to 2O C.per grm., owing to the presence of small quantities of basic carbonate. In the examination of mixtures containing magnesium oxide the following results are typical of those obtained. In each case 1 grm. was used. Magnesium Oxide. Per Cent. 50 60 70 80 90 10 20 20 40 20 Xagnesium Carbonate. Per Cent. 50 40 30 20 10 40 30 40 30 50 Asbestos. Per Cent. - - - - - 50 50 40 30 50 ~ ~ _ _ _ Increase of Temperature.0 bserved. O c. 19.0 14.8 11.5 7.2 3.8 3.4 7.1 7.2 14.3 7.2 Calculated. c. 18.5 14.8 11.1 7.4 3.7 3.7 7.4 7.4 14.8 7.4 C. A. M. Reduction of Manganese Dioxide by Nitrous Acid, and the Use of this Reaction in the Estimation of Phosphorus in Iron and Steel without Separation of Silieon. E. R. E. Muller. (Chem. Zeit., 1912, 36, 1490.)-In the author's method for estimating phosphorus without the separation of silicon (Chem.Zeit., 1911, 35, 1201) sodium peroxide was used to reduce the manganese dioxide formed. The following procedure may be substituted with advantage : After the boiling with permanganate (2 C.C. of a solution containing 40 grms. per litre), the beaker is withdrawn from the hot-plate, and 0.5 C.C. of absolute alcohol and 1 C.C.of 10 per cent. sodium nitrite solution added. On agitation the manganese dioxide is dissolved, and evolution of ethyl nitrite usually begins; 1 C.C. of concentrated ammonia is added, and the solution precipitated with ammonium molybdate solution.78 ABSTRACTS OF CHEMICAL PAPERS Not more than 0.5 C.C. of alcohol should be used, as otherwise the quantity of nitric acid present is unduly reduced.The sodium nitrite is added to start the reaction. 0. E. M. Qualitative Detection of Nitric Acid in Sulphuric Anhydride. W. N. Iwanow. (J. Rz~ss. Phys. Chem. SOL, 1912,44,1334-1337 ; through Chem. Zentralbl., 1912, II., 1944.)-In testing sulphuric anhydride for the presence of nitric acid by the diphenylamine test erroneous conclusions may be drawn in certain cases.A sulphuric anhydride containing 20 per cent. of trioxide and free from nitric acid gives no coloration with diphenylamine, but a product containing more than 20 per cent. of trioxide may sometimes give a coloration owing to the fact that tbe sulphur trioxide may act as an oxidising agent, splitting up into sulphur dioxide and active oxygen. For testing acids containing much sulphur trioxide, the author recommends that 10 C.C.of the fuming acid, containing about 30 per cent. of trioxide, should be diluted with 20 C.C. of pure sulphuric acid of sp. gr. 1-84, so that the mixture represents approxi- mately a monohydrate. The mixture is cooled, treated with 1 C.C. of the diphenyl- amine reagent, shaken, and allowed to stand for a minute; if no blue coloration appears, the acid is free from nitric acid.J. F. B. Osmium Tetroxide as an Oxygen-Carrier and the Rendering Active of Chlorate Solutions. K. A. Hofmann. (Ber., 1912, 45, 3329-3336.)-The reaction of osmium tetroxide with fats is known to be one of oxidation, the black coloration being that of the reduced osmium dioxide formed. In order to utilise this property of osmium tetroxide for practical purposes it is desirable to make the reaction catalytic by ensuring ?he reoxidation of the dioxide to the tetroxide as fast as the latter is deoxidised.The action of atmospheric oxygen in this connection is distinct, but feeble and slow ; it can be demonstrated by shaking acid solutions of leuco-bases with air and a trace of the tetroxide.Oxidising effocts which are satisfactory and rapid may, however, be carried out with oxygen under a pressure of 50 atmospheres at temperatures of 50" to 100' C. in the autoclave, using osmium tetroxide as a catalyst in the proportion of 0.01 grm. per 200 C.C. of liquid. Ethyl and methyl alcohols i n aqueous solution give, in this manner, mixtures of the corresponding aldehydes and acids.Aldehydes are comparatively resistant under these conditions ; anthracene in acetic acid solution is oxidised to anthraquinone. The most generally effective oxidising agent for preparation purposes consists of a neutral or faintly acid solution of a chlorate rendered active by a trace of osmium tetroxide, For instance, a mixture of 15 grms. of arsenious acid, 10 grms. of potassium chlorate, and 50 C.C.of water shows no reaction even after the addition of a little dilute sulphuric acid ; but if 1 C.C. of a solution of 1.5 grm. of osmium tetroxide in 100 C.C. of water be added, a violent oxidation ensues with rapid rise of temperature. A large number of analogous oxidations of inorganic and organic substances are described. ' The reaction may be utilised for the estimation of hydrazine ; for instance : 0.02288 grm.of hydrazine sulphate with 50 C.C. of water and 2 grms. of potassium chlorate, when treated with 1 C.C. of the osmium solution in a current of carbon dioxide, gave 43.64 C.C. of nitrogen, equal to 21.59 per cent., as against 21.55 per cent. calculated.INORGANIC ANALYSIS 79 Rapid oxidations of indigo carmine, quinol, aniline, benzidine, pyrocatechol, tannic acid, resorcinol, anthracene, and other substances are described.Quantitative experiments with alcohol proved that the reaction is purely one of oxidation with no tendency to chlorination. The plain solution of osmium tetroxide may be used as a test for pure benzene, which shows no blackening, whilst a trace of thiophene impurity reduces the tetroxide to the black dioxide.Pure pentane and hexane also do not reduce, whereas the commercial hydrocarbons and those with ethylene bonds reduce readily. Saturated ketones are not affected, but commercial acetone shows the black coloration. J. F. B. Estimation of Available Oxygen in Per-Salts by Means of Titanium Trichloride. L. Moser and F. Seeling. (Zeitsch. anal.Chem., 1913, 52, 79-86.)- The method depends on the reaction between titanium trichloride and the hydrogen peroxide which is formed when perborates, percarbonates, etc., are treated with water ; the reaction proceeds according to the equations : NaBO, + H,O = NaBO, + H,O, and H,O, + 2TiC1, t 2HCl= 2TiCl42H,O. Pertitanic acid is first formed, and produces a yellow coloration in the solution ; this acid is decomposed on the addition of a further quantity of titanium trichloride, and the disappearance of the yellow colour is taken as the end-point of the titration.A weighed quantity of perborate is dissolved in cold water in a flask, dilute sulphuric acid is added, and the mixture is titrated with a standardised titanium trichloride solution, while an atmosphere of carbon dioxide is maintained in the flask.The process may be applied to washing powders containing perborates, but when soap is present it is advisable to add about 10 C.C. of carbon tetrachloride after the addition of the sulphuric acid, in order to remove the fatty acids from the sphere of action of the pertitanic acid. In the case of percarbonates the sample must be dissolved in ice-cold water, and an aliquot portion of the solution then pipetted into an excess of the titanium trichloride solution; the excess of the latter is titrated with ferric sulphate solution.A current of carbon dioxide is passed through the flask during these operations. I n the case of ammonium persulphate there is no formation of pertitanic acid ; a solution of the salt is therefore treated with an excess of titanium trichloride, and the mixture then titrated with ferric sulphate solution, using potassium thiocyanate as indicator.w. P. S. Estimation of Palladium, and its Separation from Copper and Iron. M. Wunder and V. Thuringer. (Zeitsch. anal. Chem., 1913, 52, 101-104.)- Palladium forms a compound with dimethylglyoxime which is practically insoluble in dilute acids (the solubility in 2 per cent.hydrochloric acid is 0-001 per cent.); the compound is, however, readily soluble in ammonia and potassium cyanide solution, and in this respect differs from the corresponding nickel compound (cf. ANALYST, 19C9, 34, 74). The palladium compound contains 31.61 per cent. of the metal, For the estimation, the palladium solution is acidified with hydro- chloric acid, diluted to 150 c.c., and an excess of a 1 per cent.dimethylglyoxime solution (in hydrochloric acid) is added. The mixture is heated for thirty minutes80 ABSTRACTS OF CHEMICAL PAPERS on a water-bath, and the precipitate is then collected on a filter, washed, dried, and ignited. A very small flame must be used a t the commencement of the ignition in order to prevent loss of metal, but when the filter is incinerated completely the heat may be increased to bright redness.When the solution contains copper and iron in addition to palladium, the latter is first separated as described above, but a larger proportion of the reagent is required should ferric salm be present. The filtrate from the palladium compound is treated with sulphurous acid and potassium thiocyanate, in order to precipitate the copper, and the iron is then separated a8 sulphide, dissolved in hydrochloric acid, oxidised, and precipitated as hydroxide. w P.s. Detection and Estimation of White Phosphorus in Phosphorus Sesqui- sulphide. T. Schloesing jun. (Comptes rend., 1912, 155, 1461-1463.)-The method is based upon the difference in solubility of white phosphorus and phosphorus sesquisulphide in that fraction of petroleum spirit distilling below 45" C. Twenty grms.of the sample are shaken vigorously for some minutes with 125 C.C. of the solvent, and if it does not immediately clarify, the liquid is rapidly filtered through asbestos, with precautions against loss by evaporation. An aliquot portion (100 c.c.) of the filtrate is transferred to a tared flask, immersed in water at 1 5 O to 20° C.and evaporated with the aid of a water-pump, and traces of solvent expelled by a current of air, after which the residue is weighed. In the case of pure sesquisulphide tbe ratio of phosphorus to sulphur will approximate 5 =E4 In this way the following results, calculated upon the total 125 c.c., were obtained with pure phosphorus sesquisulphide alone and with the addition of 1 per cent.of white phosphorus : S , 43.6' A. B. Pure Sesquisulphide. ~ ~ ~ h ' , ~ ~ ~ Residue (mgrms.) . . . ... 284 433 Excess over 284 mgrms. ... - 149 295 { 3 4 4 3 Composition of residue = 1641 Ratio.. . ... ... S = 1311 - 55.6 S 131 - - 44-4 - P 164 - - The differences between the sums of the phosphorus and sulphur and the residues obtained were attributed to errors of manipulation.The white phosphorus added to B was not entirely recovered, a portion having combined with the sesquisulphide to form a sulphide only a fraction of which was dissolved. The amount of phosphorus remaining in the free state was calculated from these results to be 120 mgrms., or 0.6 per cent.Phosphorous and phosphoric acids, which are frequently present in commercial sesquisulphide, have no influence upon the results. The solubility of white phosphorus in the rectified petroleum spirit used was 8 grms. per litre. The phosphorescence shown by sesquisulphide containing a little free white phosphorus is greatly intensified by applying the test to the residue from the petroleum spirit.A little fine quartz sand is added to the petroleum spirit solution before evaporationINORGANIC ANALYSIS 81 in vacuo, and the last traces of solvent expelled with air. On now shaking the sand in the fiaak in the dark, phosphorescence is observed in the presence of minute traces of white phosphorus. C. A. M. Estimation of Potassium by Cobaltinitrite Method.F. H. MacDougall. (J. Amer. Chsm. SOL, 1912, 34, 1684-1686.)-1n the usual method the yellow cobaltinitrite compound, K,NaCo(N0,),,zH20, is boiled with excess of & per- manganate for several minutes, dilute sulphuric acid is added, then oxalic acid, and finally & permanganate till the end-point is reached, Thus the oxidation of the nitrite takes place in alkaline solution, and the factor for the FG permanganate is 0*00071 grm.K per 1 C.C. The author now proposes to oxidise the nitrite in acid solution, adding first dilute sulphuric acid to the yellow precipitate, and finally oxidising with permanganate, when 1 C.C. = 0*000651 grm. K. (In acid solution the cobaltic salt formed changes to the cobaltous salt with evolution of oxygen, and thus in the acid method the amount of permanganate required is greater than in the alkaline method in the proportion of 12 to 11.) The results compare favourably with the older method.A. R. T. Determination of Chromium and Vanadium in Steels. D. J. Davenport. (J. Ind. Ey. Chem., 1912, 4, 895.)-The author’s method for the estimation of vanadium (J. Ind. Eng. Chem., 1912,4,249) is extended to steals containing chromium in addition. To a solution of 9 grins.of the sample in 12 C.C. of strong sulphuric acid and 50 C.C. of water are cautiously added 25 C.C. of nitric acid (sp. gr. 1-42), oxides of nitrogen removed by boiling, and sodium bismuthate added until the permanganic acid formed from the manganese present does not disappear on shaking. The solution is diluted to 200 c.c., and, after addition of a further small quantity of sodium bismuthate, boiled for twenty minutes to convert the permanganic acid into manganese dioxide.It is cooled by the addition of 50 C.C. of water, filtered through asbestos, made up to 300 c.c., cooled, 5 C.C. of syrupy phosphoric acid added, and $a ferrous sulphate solution run in until there is an excess, as shown by testing on a plate with ferricyanide; an excess of several C.C.over the amount of +& potassium permanganate required to produce a permanent pink tint is added, the solution stirred for one minute, and the pink colour just removed with & ferrous sulphate solution. The total ferrous: sulphate less the permanganate, multiplied by 0-000173, gives the amount of chromium present.To determine the vanadium, ferrous sulphate considerably in excess of that required to reduce the vanadium and 1 grm. of powdered manganese dioxide are added in such a fine state of division that it will settle clear in fifteen seconds in a beaker of water. The solution is shaken until all ferrous iron is oxidised to ferric, as shown by the ferricyanide test, and filtered with suction through asbestos; i& potassium parmanganate is run in until a permanent pink is reached, when several C.C.in excess are added and the solution is shaken for one minute. The pink tint is then just removed with & ferrous sulphate solution. The permanganate minus the ferrous sulphate, multiplied by 0.00051, gives the vanadium present. 0. E. M.82 ABSTRACTS OF CHEMICAL PAPERS Direct Volumetric Determination of Tin.H. B. J. Rawlins. (J. Sot. Chem. had., 1913, 32, 27.)-In an investigation to ascertain the degree of accuracy attainable by technical methods in the direct determination of tin in the commercial metal, the following processes were employed: (1) Titration with excess of ferric chloride and working back with a dilute solution of titanium chloride (method of Knecht and Hibbert, J.SOC. Chem. Ind., 1905, 24, 1192); (2) titration with ferric chloride, employing starch and cuprous iodide as indicator ; (3) titration with iodine. The procedure adopted in the second and third methods consisted in oxidising the bulk of the stannous chloride by the addition of a definite volume of a strong solution of ferric chloride or iodine from an automatic burette, and completing the titration with a corresponding weak solution.It was found that by treating 1 grm. of the metal (thinly rolled or in the form of filings) with 50 C.C. of cold or slightly warm strong hydrochloric acid in a, flask through which a current of carbon dioxide was maintained, and into which a small piece of marble had been previously placed, solution was effected in from forty-five to ninety minutes, the whole of the tin being retained in the stannous condition.I n determinations made by the three methods upon commercial tin containing only traces of antimony, the maximum differences obtained (in terms of tin) were 0.14 per cent. by the first, 0.15 by the second, and 0.10 by the third process. Copper in small quantity was found to be practically without influence on the titanium chloride titration ; it is generally known, however, that finely divided antimony is dissolved by solutions of ferric chloride and iodine, but since this constituent is present in only the smallest quantity in many brands of commercial tin-and when present may be determined and allowed for- the author considers that the results for tin obtainable by the direct methods indicated are not only sufficiently accurate for technical purposes, but in many cases more correct than those obtainable by the ‘( difference ” method involving rapid technical determinations of the impurities.Estimation of Titanium in the Presence of Iron. W. J. Thorntonjun. (Zeitsch. anorg. Chem., 1912, 79, 190-194.)-The following rapid modification of Gooch’s method of estimating titanium in the presence of iron is applicable in the case of minerals containing but little aluminium.Iron is first removed by adding tartaric acid (three times the weight of the total oxides), introducing hydrogen sulphide until the iron is converted into the ferrous state, then adding a slight excess of ammonia, and continuing the current of hydrogen sulphide until the iron is com- pletely precipitated, leaving the liquid still faintly alkaline to litmus.The precipitate is separated and washed with very dilute ammonium sulphide solution, and the filtrate and washings will then contain the whole of the titanium. The tartaric acid in solution must next be destroyed, and this is best done by means of a mixture of sulphuric and concentrated nitric acid.For example, to 25 C.C. of a solution containing about 0.1 grm. of titanium oxide there are added from 10 to 12 C.C. of concentrated’ sulphuric acid, and the liquid is evaporated until the tartaric acid begins to carbonise. The dish is then covered with a clock-glass, and the heating continued until frothing begins, after which its contents are cooled and cautiouslyINORGANIC AXALYSIS 83 treated with 5 C.C.of concentrated nitric acid. The pale yellow viscous fluid eventu- ally obtained is poured into 100 C.C. of cold water, and the titanium precipitated by the basic acetate method. A single precipitation is sufficient when only a little aluminium is present, and in this way the original method is greatly accelerated.C. A. M. Present Position and Importance of Analytical Chemistry. W. Fre- senius. (Zeitsch. arqew. Chem., 1912, 25, 2513-2518.)-Reviewing the development of analytical chemistry, the author states that this branch of the science, though merely a means to an end, has become a factor of indispensable importance in most departments of public activity, comparable in its fundamental utility with the art of calculating. In the domain of pure science, also, the fixation of the atomic weights, the periodic law, the phenomena of isomorphism, isomerism, and homologous series, are founded on the results of chemical analysis.The reawakening of interest in inorganic and physical chemistry, which may be dated from about 1880, has led to a complete change of attitude in the scientific treatment of analytical chemistry.In this connection may be cited the recognition of reversibility of reactions and the laws which govern it, the recognition of the influence of the size of particles on their solubility, the conceptions of occlusion and adsorption, the ionisation of electrolytes- I n volumetric analysis many reactions, which do not involve the removal of one of the components in the form of a precipitate or a gas, have been recognised as com- plex equilibria, the results of which do not follow the simple chemical equations, but depend on the total factors present ; thus, it is commonly found that volumetric solut o can only be standardised against substances similar in nature to the material analysed.The application of physical methods has attained a great development, and the principles involved in the standardisation and use of ‘‘ con- stants ” for analytical purposes have opened up new fields. The ionic theory has revolutionised the previous conceptions of acidimetry, and the analyst now has to take into account the temporary ionic conditions of the liquid to be titrated, often disregarding the total potential acidity as revealed by ordinary titration. Micro- scopic analysis, starting from petrography, has spread to metallurgy and other fields of usef ulnees.J. F. B. Microchemical Reagents. W. Lenz. (Zeitsch. anal. Chem., 1913, 52, 90-99.) -Directions are given for the preparation and storing of reagents used in micro- chemical analysis. Glass vessels must be avoided, as they yield soluble substances to acids, etc. ; for instance, if a drop of sulphuric acid which has been kept in a glass bottle is evaporated on a microscope slide, a distinct residue will be obtained in which potassium and sodium may be detected microchemically. It is recom- mended that all acids, ammonia, and solid reagents, be stored in small silica bottles, and that water (freed from ammonia) he stored in a gilded silver flask. The liquid acids and ammonia, must be distilled from silica flasks, the condenser and84 t * /c--c ABSTRACTS OF CHEMICAL PAPERS C receiver also being made of silica. Microscope slides made of silica, should be used in microchemical analysis. w. P. s. APPARATUS, ETC. Estimation of Solubilities. W. R. Forbes. (Chem. News, l912,106,300.)-!J!he author has modified Goldschmidt’s apparatus (see figure) by widening the filter area, eliminating rubber connections, and sirnplify- ing the stirrer (G). Water and the salt are placed in A , and the tap D closed. When the solution is saturated, D is opened, and the liquid drawn into the weighing bottle B by exhausting through C. The weighing bottle is detached from its ground-glass joints with A and C, dried and weighed. When in use the apparatus and stand are placed in a, water-bath at the desired tem- perature. A. R. T.

ISSN:0003-2654    

DOI:10.1039/AN9133800075

出版商:RSC    

年代:1913

数据来源: RSC

摘要:

84 ABSTRACTS OF CHEMICAL PAPERS REVIEWS. GENERAL CHEMISTRY OF THE ENZYMES. HANS EULER. Translated from the revised and enlarged German edition by THOMAS H. POPE. New York: John Wiley and Sons. London : Chapman and Hall, Ltd. 1912. Pp. 311. Price 12s. 6d. net. The author in this work states that he does not claim to give a complete synopsis of oar knowledge of the enzymes, but only to review the more important facts from a general standpoint, and to fit them, so far as is possible, into their proper places in the fabric of general and physical chemistry.The volume is based on two reports written by the author for the (‘ Ergebnisse der Phyaiologie ” in 1907 end 1910, and he expresses the hope that the present monograph, which is intended more especially as an aid to scientific research, will also prove useful to those concerned with the practical applications of enzymic actions.Many students of this branch of chemistry will echo the question of the author, and ask whether the time is yet ripe for giving a representation of the physical chemistry of the enzymes, but after a perusal of the present laborious undertaking, they will probably agree with him that the attempt should be made, especially as the results of many of the more recent and exact investigations correspond more closely with those required to satisfy physico-chemical theories.The modern technical methods of measuring enzymic activity are dailyREVIEWS 85 becoming more numerous and important, as the ever-growing and highly specialised literature of the subject bears witness, and it would surprise many not familiar with recent research to learn the high degree of accuracy in conjunction with the most refined methods which are now employed in the assay and standardisation of such preparations as commercial pepsin, rennin, or diastase.Sorenson and many others have emphasised the extreme importance of precision in the technique of such work, and essential details, such as the exact reaction of the media employed and other points previously too often overlooked, now receive due attention from all careful workers.Following a chapter on the special chemistry of the enzymes is an account of their physical properties, so far as they are known, and of the ‘‘ activators (co- enzymes), paralysors, and poisons ” known to affect their actions. The longest section of the book, and that to which most attention has evidently been given, deals with the Chemical Dynamics of Enzyme Reactions, and the work of a host of investigators in this much-worked field is in the main ably summarised.The author would appear, however, to have missed the significance of an important paper by Adrian Brown, to which insufficient justice is done on p.162, but rightly points out that some of the recorded experimental work (notably some of Henri’s) is vitiated from the fact that when optical methods were employed for measuring such reactions as the inversion of cane-sugar, sufficient care was not taken to obviate the disturbing effects of bi-rotation. Short chapters on ‘‘ The Influence of Temperature and Radiation on Enzymic Reactions,” ‘ I Chemical Statics in Enzyme Reactions,” ‘‘ Enzymic Syntheses,” 4‘ Specificity of Enzyme Action,” and an Appendix containing a very brief description of “Practical Methods,” bring the volume to a, close.There are both Subject and Author Indexes, but they are poor and ill-arranged, the irritating method having been adopted of following a name or a subject by a string of page numbers, without further differentiation or subdivision.I t is impossible for the reviewer to attempt the appraisement in detail of a book covering so large a field of work, but so far as he is able to judge from those portions dealing with branches of the subject with which he is familiar, much care has been taken in bringing the information well up to date, and in making a judicious sdection from the original published work.The author acknowledges his indebtedness to Mr. T. H. Pope, not only for his excellent translation, on which he is to be congratulated, but also for improve- ments and additions in the section dealing with practical methods, and for the refarences to the literature. H. F. E. HULTON.ALLEN’S COMMERCIAL ORGANIC ANALYSIS, VOL. 5. A reply by W. P. DREPER to certain criticisms made by the reviewer (ANALYST, 1912, 37, 385) appears in the Journal of the Society of Dyers and Colourists, vol. xxix., pp. 19-20.86 INSTITUTE OF CHEMISTRY INSTITUTE OF CHEMISTRY. PASS LIST : DECEMBER-JANUARY EXAMINATIONS. Of twenty-seven candidates who presented themselves for the Intermediate Examinations held in Glasgow in December, and in London in January, eight passed : A.L. R. Clarke, B.Sc. (Lond.), G. N. Grinling, C. W. McHugo, El. A. Phillips, H. V. Potter, A. B. Stitch, B.Sc. (Gles.), H. E. L. Thomas and I?. D. White. Of nineteen condidates who presented themselves for the Final Examination, fifteen passed. In the Branch of Mineral Chemistry: C. D. Barber, B.Sc. (Lond.), T. T. F. Crtrtwright, B.Sc. (Lond.), A.R.C.S. (Lond.), R. M. Doidge, B.Sc. (Lond.), F. M. Potter, B.Sc. (Lond.), A.R.C.S. (Lond.), and J. A. Watson, A.C.G.I. ; in the Branch of Metallurgical Chemistry : F. G. Conyers ; in the Branch of Organic Chemistry : K. C. G. Arbuthnot, B.A. (R.U.I.), J. C. Earl, and F. G. Tarn; in the Branch of the Chemistry of Food and Drugs, and of Water: J. W. Flint, B.A. (Cantab.), D. R Frazer, H. E. Watts, Ph.D. (Zurich), B.Sc. (Lond.); for the Certificate: E. J. Wilson, M.A. (Cantab.), (F.I.C.) ; in General Chemistry : B. W. Drinkwater, A.R.S.M., A.R.C.S. (Lond.), and W. C. Ball, M.A. (Oxon.), So.D. (T.C.D.).

ISSN:0003-2654    

DOI:10.1039/AN9133800084

出版商:RSC    

年代:1913

数据来源: RSC