摘要:

OCTOBER, 1912 Vol. XXXVII., No, 439. THE ANALYST. PROCEEDINGS OF THE SOCIETY OF PUBLIC ANALYSTS AND OTHER ANALYTICAL CHEMISTS. THE IODIMETRIC TITRATION OF SULPHITES IN PRESENCE OF ALCOHOL AND SUGARS. BY JULIAN L. BAKER, F.I.C., AND F. E. DAY, B.Sc., A.I.C. IN a paper published recently (J. Inst. Brewing, 1911, 17, 465; ANALYST, 1911, 36, 495), dealing with the behaviour of sulphites added to beer for preservative purposes, we showed that the bulk of the sulphite combines with various constituents of the beer, with the formation of stable, chemically inert bodies.We based this conclusion partly on the differences between the results obtained by direct titration and by the distillation method. K. Farnsteiner (Zeitsch. Untersuch. Nahr. Genussm., 1902, 5, 1124) employed a method for estimating sulphites in light-coloured liquids, such as lime-juice, which consisted in adding alkali and then acid previously to titration.We found that under these conditions a higher value for sulphurous acid is obtained than by direct titration. Among several constituents of beer, whose action on sulphites we tested separately, was alcohol, industrial spirit, partially purified by repeated distillatiou , being employed.We have considered it desirable to repeat our experiments, using pure alcohol; and, contrary to our expectations, we have found that the results obtained by Farnsteiner’s method were considerably lower than by direct titration. Potassium hydrogen sulphite was made up to ZT strength with (a) distilled water containing 5 per cent.by volume of pure alcohol, and (b) distilled water alone. Twenty C.C. portions diluted with water were titrated with TG iodine under varying conditions : T i m after Preparation of Solution. 5 per cent. alcohol : 4 hour ... ... ... 20 hours ... ... ... 70 ,, ... .., .I. At once ... ... ... 70 hours ... ... ... No alcohol : Direct Titration. 9.70 9.55 9.40 9.80 9.40 C.C.Iodine used. After Acidifying with HC1. Farnsteiner’s Method. 8-90 9-10 8.95 8.80 8.65440 BAKER AND DAY THE IODIMETRIC TITRATION OF Though the results are unaffected by the presence of alcohol, which plainly does not combine with the sulphite, yet the difference in the values of the second and third columns as compared with the first is marked, and in the opposite sense to that anticipated.The purity of the reagents was beyond question, and, if the acid and alkali were previously mixed and then added to the sulphite solution, a normal titration result was obtained. I t seemed probable to us that the oxygen dissolved in the liquid might be the cause of this difference, and the following experiments were made to throw some light on the matter: A solution of potassium hydrogen sulphite was titrated with iodine under varying conditions, 70 C.C.of either distilled or tap water (both saturated with air, unless otherwise stated) being used to dilute the liquid before titration. I n the table, the results obtained by diluting with distilled and tap water are recorded in separate columns, and the constituents of the mixture titrated are given in the order in which they were added. The total volume titrated in most cases was 80 c.c., which contains approximately 0*0007 grm.dissolved oxygen : Mixture in Titration Flask 5 C.C. sulphite + 70 C.C. water . . . ... 5 C.C. sulphite + 2 C.C. concentrated HC1 5 C.C. sulphite + 70 C.C. water + 5 C.C. 6 per cent. NaOH+2 C.C. HC1 5 C.C. sulphite + 70 C.C. freshly-boiled water and 5 C.C.6 per cent. NaOH + 2 C.C. HCl 5 C.C. sulphite + 70 C.C. freshly-boiled water + 5 C.C. concentrated HCI . . . ... 70 C.C. water+5 C.C. 6 per cent. NaOH f + 2 C.C. HCl+ 5 C.C. sulphite \ 1 .( Time between Mixinu and Titlszng. At once At once 7 minutes At once 3 minutes At once At once At once 7 minutes C.C. Iodine used. i O c c. Distilled Water. i O c.c.* Tap Water.4.9 4-6 4-6 4.8 4.3 - - 5-0 4.7 It is evident that in dilute acid solutions the sulphite rapidly combines with the dissolved oxygen, and it seems likely that the action is hastened by the act of neutralising the added alkali, thus exhibiting the phenonienon of an (‘ induced reaction.” The amount of oxygen dissolved in the solution is capable of oxidising 0.9 C.C. of ij sulphite.It will be noted that the addition of a considerable quantity of hydrochloric acid appreciably lowers the titration value. The experiments plainly show the inaccuracy of estimating the amount of sulphurous acid in liquids by Farnsteiner’s method. Having traced the source of the discrepancy in the previous results to the disturb- ing effect of dissolved oxygen, and having also shown that pure alcohol does not combine with sulphites, experiments similar to those described in our previous paper * This water had a distinct alkaline reaction t o methyl orange.SULPHlTES I N PRESENCE O F ALCHOHOL AND SUGARS 441 Hour.were carried out with alcohol derived from various sources. A & solution of potassium hydrogen sulphite was prepared, containing 5 per cent. of the alcohol under examina- tion, and titrated with iodine.I n the table, the column headed ‘( real loss ” repre- sents the difference between the amount of sulphurous acid actually present after four weeks, aB determined by the distillation method, and that originally present. The ‘( apparent loss ” is the difference between the amount shown by direct titration and that originally present ; this value includes the “ real loss,” together with the amount of sulphite in stable combination.The difference between the ‘‘ apparent loss ” and the g L real loss ” is 8: measure of the sulphite in combination : $ 4 Hours. Pure alcohol Alcohol distilled from old ale ... Methylated spirit . . . Brandy ... ... 10*00 C.C. 2- Iodine Solution used. 1 0 9.90 Bv Direct Titration Alcohol from Old Ale.“ after- illethylated Spirit. 9-70 9.45 10.15 9.95 9.45 9.90 23 Hours 9.90 9.95 9-25 9.90 50 Hours 9.9 9-8 9.2 9-8 After 4 Weeks. Direct. 9.20 9.35 9.10 9.70 Distilled 9-40 9-55 9.60 9.90 Expressed as C.C. & Iodine. Apparel1 t Loss. Real Combined Loss. SO,. 23 H0ul.s. 0.10 0.05 0.75 (0.25 (0.10 4 Weeks 0.80 0.65 0.90 0.30 0-45 4 Weeks 0.60 0 -45 0.40 3.10 3.25 ::: 4 Weeks.0.20 0.20 0-50 )0.20 I t would be expected that the (‘ real loss ” would be greater where least com- bination had occurred, but this idea is hardly borne out by the last column. For example, the L( real loss ” is far less in the case of brandy than in that of pure alcohol, whereas, according to the results, the amount of sulphite in combination is the same.As regards odour and flavour of sulphurous acid, the test solutions were arranged as above, most odour-and it is to be supposed least combination-occurring in the solution with pure alcohol, and least odour and most combination in the brandy solution. This was confirmed by blowing a litre of air, during a seven and a half minutes’ period, through 10 C.C. of each. On titration with iodine tbe following figures were obtained : Pure Alcohol.Brandy. Before ... ... After . . . ... Loss ... ... 9-20 8-75 0.45 9-35 9.10 0.25 9.10 9.05 0.05 9.70 9.60 0.10 * The diluted brandy showed a slight initial absorption of iodine, which has been allowed for in the lower set of figures.442 IODTMETRIC TITRATION OF SULPHI I‘ES, ETC. These figures confirm the previous ‘( real losses,” and from these experiments we infer that at least two states of combination exist between sulphites and some con- stituent of alcohols of commercial origin.One results in either decreased volatility of the sulphurous anhydride, or resistance to oxidation by molecular oxygen ; the other, more stable, resists even oxidation by iodine, The latter state seems to occur but slightly in the case of pure alcohol, or alcohol derived from fermented liquids, but is exhibited in a marked degree even by good quality methylated spirit.I n our previous paper we showed that there was a considerable amount of com- bination between maltose and dextrin and sulphites. We have extended tbese observations by including glucose and cane-sugar. A 10 per cent.solution of t h e sugar was mixed with potassium hydrogen sulphite and titrated with +& iodine : Sugar. C.C. Sugar Solution. C.C. KHSO,. Duration before Tit ration. C.C. -U Iodine. 1 0 Glucose ... ... 9 , 9 9 . .. ... ... ... Sucrose ... ... ... ... 2, 9 9 ... 5.0 10.0 50.0 10.0 40.0 50.0 10.0 10.0 10.0 10.0 10.0 10.0 - 10 minutes 10 minutes 5 minutes 19.4 19.4 19.3 20.0 20.0 20.0 The apparent loss of sulphite caused by the addition of glucose is striking, and can probably be correlated with its aldehydic constitution, which would explain wby cane-sugar does not show any such effect.The conclusions to be derived from the preceding experiments are, we consider, as follows : 1. That sulphurous acid is readily oxidised by dissolved oxygen in dilute acid solution. 2. That this action is greatly facilitated by the occurrence in the solution of a reaction between alkali and acid, This obviously affects the results obtained by the method of sulphite estimation proposed by Farnsteiner (Zoc. cit.). 3. That commercial alcohols and alcoholic liquids contain substances capable of combining with sulphites. These substances partially prevent the oxidation of sulphites by iodine. 4. That glucose, by virtue of its aldehydic structure, combines to a certain extent with sulphites, but cane-sugar does not. STAG BEEWERT, LOKDOK.

ISSN:0003-2654    

DOI:10.1039/AN9123700439

出版商:RSC    

年代:1912

数据来源: RSC

摘要:

THE GRAVIMETRIC SEPARATION OF ZINC AND NICKEL 443 Weight O f Nickel taken. THE GRAVIMETRIC SEPARATION OF ZINC AND NICKEL. BY T. COCKBURN, F.I.C., A. D. GARDINER, AND J. W. BLACK. THE unsatisfactory results obtained by the commoner methods for the separation of zinc and nickel renders the analysis of German silver a matter of some difficulty. For the purpose of our inquiry we selected a few of the better-known processes, omitting those involving the uge of cyanides or fixed organic acids, whilst we directed special attention to obtaining zinc sulphide in a form in which it could be filtered--a, desideratum which is frequently unattainable.In order to obtain strictly comparable results, the same standard solutions of zinc and nickel and the same graduated glass apparatus were used throughout.1. Precipitation of Zinc as Zinc Subhide from an Acetic Acid Solution.-We found considerable dificulty in finding the correct conditions when employing this process. In many of our trials, either the precipitation of the zinc or the physioal condition of the zinc sulphide proved unsatisfactory, but by adhering to the following details our best results were obtained : To a faintly acid solution of the two metals a solution of sodium carbonate is added until a faint turbidity is produced, then 100 C.C.glacial acetic acid, the solution thoroughly cooled, and hydrogen sulphide passed into it for one hour at the rate of about 2 bubbles per second (cf. Lewis, J. SOC. Chem. Ind., 1909, 78, 587). These conditions insure the production of zinc sulphide perfectly white in colour, and in a granular form permitting of easy filtration. The precipitated zinc sulphide is allowed to stand in the cold for some bours, and the clear supernatant liquid then completely decanted through a hardened Schleicher and Schiill No.5 paper. The precipitate is washed with sulphuretted hydrogen water containing 2 per cent. ammonium acetate.After drying, the precipitate is separated from the paper, and ignition started at a low red heat, the temperature being gradually increased until a bright red heat is obtained. The duration of the ignition at a gradually rising femperature lasted one hour, when the zinc sulphide was entirely converted into zinc No. of C.C. of Total Weight Acetic Acid. Solution. Zinc found.Glacial Volume of' of Difference. oxide. The precipitates were tested for nickel by the exceedingly delicate reaction discovered by Tschugaeff (Chenz. Zeit. Rep, 1905,29, 247)-namely, the production of a dark scarlet nickel glyoxime when to the dilute hydrochloric acid solution of the precipitates, made slightly ammoniacal, was added an alcoholic solution of dimethyl- glyoxime : 1 3 3 4 5 TABLE I.0.1102 0.2203 0.3672 0.3672 0.6793 0.1934 0.1934 0,1934 0.1934 0-1934 I 40 210 0.1105 + 0.0003 50 260 0.2211 + 0.0008 100 260 0,3675 + 0~0003 100 260 0.3668 - 0*0004 100 260 0.6791 - 0.0002444 COCKBURN, GARDINER, AND BLACK : The results were negative in the instances shown in Table I., but we found that, when using larger quantities of nickel there was a tendency for nickel to appear in the zinc precipitate, and consequently high results mere obtained.2. Precipitation of Zinc as Zinc Xzdphide iiz Presence of Formic Acid (Waring's Method).-This process, which we prefer to the acetic acid method, was operated a s described in Low's '' Technical Methods of Ore Analysis," 5th ed., p. 294. To the acid solution of zinc and nickel is added a drop of methyl orange, then from a pipette a very dilute solution of sodium hydroxide is run in until the pink colour barely but permanently changes to a light yellowish tint.Then sufficient formic acid (50 per cent. strength) is added drop by drop just to restore the permanent pink colour, and 8 C.C. is added in addition. The solution is diluted to about 250 C.C. (or so that 100 C.C.contains not more than 0.2 grm. of metallic zinc), and heated to about 80" C . Sulphuretted hydrogen is then passed through the solution under a slight pressure, and when the zinc has been completely precipitated the flask is disconnected, the precipitate allowed to subside, and the clear super- natant liquid passed through a hardened No, 5 filter or ordinary Swedish filter-paper, and the precipitate washed with hot water.As in the foregoing process, the zinc was weighed as zinc oxide : TABLE 11. No. of Experiment. 1 2 3 4 5 6 7 Weight of Zinc taken. Grm. 0.3672 0.1836 0.1836 0.0734 0.0734 0.2570 0.0734 Weight of Nickel taken. Weight of Zinc found. Grrii. 0.0704 0.0704 0.1760 0.1760 0.3521 0.3521 0.7042 Grm. 0.3684 0.1844 0.1827 0.0724 0*0730 0.2580 0-0769 Diflerence.Grin. + 0.0012 + 0.0008 - 0*0009 - 0-0010 - 0.0004 + 0.0010 + 0-0035 The precipitates were tested for nickel by dimethylglyoxirne. Positive results were obtained in Nos. 6 and 7. We found this method rapid and easily worked, whilst the separation, except in the case of No. 7, which contained a high proportion of nickel, was clean and sharp. 3. Precipitation of Zinc as Zinc Xzdphide from a Solution faintly Acidi,fied with Hydrochloric Acid.-The results obtained by this method were unsatisfactory, and after an extended trial it was abandoned.As we anticipated, the main difficulty was to determine the quantity of free acid to employ, whilst the constantly increasing proportion of highly ionised free acid militates against accurate results being obtained.4. Zimmermann's Process (Ann. d. Chem. und Pharm., 1879, 199, 3 ; 1880, 204, 226).-More was expected of this method, biit notwithstanding the fact that we carried out the process exactly as described in Treadwell, vol. ii., p. 127, we were unable to obtain concordant results.THE GRAVIMETRIC SEPARATION OF ZINC AND NICKEL 445 No. of Experiment. With a view to estimating the nickel in the filtrates from the above, we reviewed the recent work of L.Dede (ANALYST, 1911, 36, 598), which promised to obviate the error arising from the well-known occlusion of alkali by nickel hydroxide. Dede employed potassium persulphate instead of bromine as the oxidising agent, and his results indicated an accuracy of k0.2 mgrm. on weighings up to 0-3 grm.The results obtained by us did not conform to this degree of accuracy, notwith- standing the fact that the amount of alkali required in each test was calculated, and great care taken to employ only the smallest possible excess. We found that the precipitates and the nickel reduced therefrom invariably contained alkali, the amount of occluded matter being approximately proportional to the concentration of the nickel.The following results, which are typical of many obtained, plainly indicate this : TABLE 111. Nickel taken. Nickel fonnd. DiRerence. 1 2 3 Grin. 0.0704 0.1408 0.2464 Grm. 0.0747 0-1516 0.2598 Grni . + 0.0043 3- 0.0108 + 0.0134 Separation of Nickel from Zinc.-In close connection with the foregoing work, we made an examination of the dimethylglyoxime method of separating nickel from zinc as detailed by 0.Brunck (ANALYST, 1907, 32, 431). To the solution, first neutralised with dilute ammonia and rendered faintly acid with dilute hydrochloric acid, is added a 1 per cent. alcoholic solution of dimethylglyoxime in amount equiva- lent to seven times the quantity of nickel present. This was followed by the addition of a few C.C.of 10 per cent. sodium acetate solution. The solutions were maintained at the boiling-point for half an hour, filtered through a, Gooch crucible having an asbestos felt, and washed with hot water. The precipitate was weighed ZEB Ni(C,H70,N2),. after drying at 110" C. TABLE IV. of Experiment. No. 1 2 3 4 5 6 7 Weight of Nickel taken. Weight of Zinc taken. Weight of Nickel found.Grill. 0.0704 0.0704 0.0704 0.0704 0.1408 0.1408 0.1408 Grm. 0.0734 0.3672 0.5508 0.1468 0.3672 - - Grm . 0.0714 0.0709 0.0712 0,0724 0.1407 0.1408 0.1410 Difference. GrtX + 0~0010 + 0.0005 + 0.0008 + 0.0020 - 0*0001 r 0~0000 + 0.0002446 ABSTRACTS OF CHEMICAL PAPERS The nickel glyoxime forms an extremely bulky precipitate, and we found that the concentration of 0.07 grm. of nickel per 250 C.C. was as high as desirable. The process is applicable to the determination of nickel in the filtrates obtained from the separation of zinc after the removal of the sulphuretted hydrogen, formic acid, etc. The results obtained are shown in Table IV. One of us is making an examination of the dicyan-diamidine method for the estimation of nickel with special reference to German silver, and will shortly publish his results. CORPORATION CHEMICAL DEPARTMENT, GL ASGOW.

ISSN:0003-2654    

DOI:10.1039/AN9123700443

出版商:RSC    

年代:1912

数据来源: RSC

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446 ABSTRACTS OF CHEMICAL PAPERS ABSTRACTS OF PAPERS PUBLISHED IN OTHER JOURNALS. ANALYSIS OF FOOD AND DRUGS. Estimation of Benzaldehyde in Maraschino Cherries and Liqueur. A. G. Woodman and L. Davis. (J. Ind. and Eng. Chem., 1912, 4, 588-589.)- The following method is recommended for this estimation, which aBords a means of determining the genuine nature of these products : 100 C.C. of the liquor from Maraschino cherries, or 50 C.C.of the liqueur, are diluted with water to 140 c.c., and 110 C.C. distilled over. The amount of alcohol in the distillate is estimated approximately from the sp. gr., and sufficient alcohol or water added to 100 C.C. of the liquid to make its content of alcohol approximate to 10 per cent. by volume. One hundred C.C. of the phenylhydrazine reagent (freshly prepared by thoroughly shaking 3 C.C.of glacial acetic acid with 40 C.C. of water and 2 C.C. of pure phenyl- hydrazine, and filtering till clear) is added as soon as possible after the distillate is obtained, and the mixture vigorously shaken for ten minutes. The liquid is filtered through a tared Gooch crucible, washing the precipitated hydraxone with cold water, and finally with 10 C.C.of dilute alcohol (10 per cent.). A rotary motion of the liquid during filtration prevents loss of hydraxone, which has a tendency to adhere to the sides of the vessel. The precipitate is dried in a vacuum desiccator for twenty-four hours, or at 70" to 80' C. in a vacuum oven for three hours, keeping the precipitate away from strong light. A blank experiment must be made, and the weight of precipitate deducted.The weight of hydrazone corrected, multiplied by 0.5411, gives the weight of benxaldehyde present. The method is applicable to the determination of the benzaldehyde in almond extracts, using 10 C.C. of the extract diluted to 100 C.C. with water, and 15 C.C. of the reagent. Control experiments with pure benxaldehyde showed the method to give results from 95 to about 98 per cent.of the theoretical. Commercial samples of Maraschino cherries were found to contain from 4 to 36 ingrms. of benzaldehyde per 100 c.c., and the liqueurs from 0 to 41 mgrms. per 100 C.C. Genuine Maraschino appears to have a very low benxaldehydeFOOD AND DRUGS ANALYSIS 447 content, and Xaraschino cherries showing a relatively large amount of the aldehyde are in all probability artificially flavoured.A. R. T. Estimation of Crude Fibre. E. Gury. (Mitt. Lebensmitteluntersuch. u. Hyg., 1912, 3, 99-105 ; through Chem. Zentralbl., 1912, II., 556-557.)-The author has sub- mitted filter-paper, cocoa, cocoa-shell, and sawdust to Konig’s process ( Unters. Zandw. u. gew. Wichtiger Stofe, third edition, p.249), Parry’s modification (Chemist and Druggist, 1911, 167) of Henneberg’s process, Filsinger’s process, and to a modification, now described, of the Zeisel-Stritar process (Ber., 1902, 35, 1252). The modification consists in treating the finely-divided, fat-free substance (1 to 1.5 grm.) with 200 C.C. of water and 10 C.C. of concentrated lactic acid, the whole being boiled under a reflux condenser for thirty minutes.The function of the lactic acid is to render the material more open to the attack of the reagents used subsequently; it also shortens the time required for filtration. The insoluble matter is filtered off on an ordinary filter-paper, washed, and returned to the flask with 180 C.C. of water and 20 C.C. of nitric acid, and, after digesting for thirty minutes, is submitted to the process of Zeisel and Stritar.Konig’s method, as well as that of Parry, leads to the hydrolysis of from 13 to 16 per cent. of the cellulose in filter-paper, whereas the method of Zeisel and Stritar does not attack cellulose. Yet the methods of Konig and Parry frequently discover more than 50 per cent. more crude fibre in cocoa or cocoa-shell than is found by the author’s modification of Zeisel and Stritar’s method.This is due to the fact that, even with very fine division of the sample, the interior portions of the larger particles escape the action of the reagents, unless opened to this action iu some such way as that now suggested. Even when using his lactic acid method, the author subjects cocoa and cocoa-shell to special methods to secure fine division of the sample.The paper includes a description of a small winnowing-machine of siniple construction. By means of this machine the finer particles of a small sample are driven forward, and the heavier residue is repeatedly ground and returned to the machine until all is fine enough. In view of the small difference in crude fibre content of cocoa mass (5.5 to 8 per cent.) and cocoa-shell (11 to 18 per cent.), the author thinks that an adverse judgment on cocoa should never be based on the percentage of crude fibre alone.On the other hand, he thinks the Swiss Lebensmittelbuch is unduly lenient in fixing 11 per cent. as the permissible limit of crude fibre in cocoa. Though Konig’s method may show nearly 9 per cent. of crude fibre in some genuine samples, the author’s process never discovers as much as 8 per cent.Filsinger’s method is much too crude to give results of any value in examining cocoa for shell. G. C. J. Modification of the Sweeney Method for Crude Fibre. C. Kennedy. (J. Ind. and Eng. Chem., 1912, 4, 600-601.)-Sweeney (U.S. Dept. Agri. Bur. Chena. BUZZ., No. 137, 157) has modified the U.S.A. official method of fibre determination, by dispensing with the filtration of the material after boiling with acid.He merely neutralises the whole with 10 per cent. caustic soda and then adds 200 C.C. of boiling 2.65 per cent. caustic soda for the final boil. This neutralisation, the author points448 ABSTRACTS O F CHEMICAL PAPERS Grms. Ether Dis- N~EE:$ b loo Grms- out, throws down a certain amount of the material dissolved by the acid, and thereby introduces an error, since the precipitate will be weighed as fibre.It is recommended that, instead of neutralisation as carried out by Sweeney after boiling with acid, suffi- cient boiling caustic soda should be added in one operation to leave 1-25 per cent. soda after its addition. Boiling for half an hour follows, and the fibre is filtered on a linen filter and washed free of alkali.The precipitate is then washed on the filter with boiling 1.25 per cent. sulphuric acid, thus dissolving any material precipitated by the addition of alkali, and finally washed free of acid with water. The advantage of the Sweeney method over the official method-namely, the saving of time and trouble due to two filtrations-is thus preserved, and the results as recorded show that the modification proposed yields results in agreement with the official figures within the experimental error, which is not the case with the Sweeney method.H. F. E. H. c,c. Etller (150 c.) ' Dissolved by 100 C.c, Normal Salt Solution. Solubility of Ether in Normal Salt Solution. R. R.Bennett. (Phamz. J., 1912,89,146.)-The author has determined, by the cryoscopic method, the solubility of pure and commercial ether in ( ( normal " salt solutions, prepared by dissolving 0.91 grm. pure sodium chloride in 99-09 grms. of distilled water. The freezing-point of this (' normal" solution is - 0.56' C. When commercial ether is added to the salt solution, the freezing-point of the solution is always a little lower than when the same quantity of pure ethyl ether has been added.This is due to the fact that alcohol has a smaller molecular weight than ether, and therefore produces a greater depression. I t is found that there is increased molecular dissociation in the salt solution in the presence of ether. The solubility results are shown below : Pure Ethyl Ether.Solution, Salt Solution. Temperature, "C. 0" 5" 10" 1 5 O 20" 25" 30" 13.08 11-15 9-45 8-10 6.87 5.96 5-30 18-27 15.58 13.20 11.31 9.60 8.33 7-40 Purified Ethyl Ether Prepared from Methylated Spirit. 13.46 11.55 9 -87 8.50 7-38 6 *46 5.83 18.80 16.14 13-79 11.87 10.31 9-02 8.14 The amount of ether present in solution at the different temperatures was ascertained by reference to a curve of freezing-points plotted out from actual deter- minations mado on solutions containing known quantities of ether. A.R. T.FOOD AND DRUGS ANALYSIS 449 Examination of Methods used in the Analysis of Honey. J. Fiehe and Stegmuller. (Arbeit. Kaiserl. Gesundheitsamte, 1912, 40, 305-356.)-The authors give the results of a critical examination and comparison of various methods which have been proposed and which are used for the analysis of honey.The results of their work may be summarised as follows : The total solids of honey may be estimated accur- ately as follows : The honey, or its solution, is mixed with sand and dried at about 65" C. in a closed vessel from which the air is exhausted, and to which a current of dry sir is admitted in such quantity that the pressure in the vessel is maintained at about 30 mm.When the total solids are calculated from the sp. gr. (d) of a 20 per cent. d-1 only approximately solution of the honey, according to the formula, T. S - ' - 0.0007714' correct results are obtained. Litmus-paper is the best indicator to use in titrating the acidity of honey, and, as it is doubtful whether the acidity is due entirely to &he presence of formic acid, the result should be expressed in C.C.of alkali solution. The estimation of the alkalinity of the ash of honey may be combined with a simple acidimetric titration of the phosphates present; the weighed ash is heated with 20 C.C. of i> hydrochloric acid in a covered flask on a water-bath for one hour and, after cooling, the solution is titrated with & alkali solution using methyl orange as indicator.Two C.C. of a neutral 2 per cent. calcium chloride solution are now added, together with a few drops of phenolphthalein solu- tion, and the titration with alkali is continued until a pink coloration is obtained; lthe quantity of alkali used in this second titration is equivalent to the phosphate present, each C.C.of & solution corresponding with 0.0035 grm. of P,O,. The sugars, according to the author, should be estimated gravimetrically. As regards the tests which have been proposed for the detection of artificial invert sugar, Fiehe's reaction (ANALYST, 1908, 33, 397) yields the most trustworthy results, especially in combination with the test for enzymes (ANALYST, 1910, 35, 165); the presence of starch syrup may be detected by a test also described by Fiehe (ANALYST, 1909, 34, 440).Ley's test (ANALYST, 1907, 32, 291) was found to be unsuitable for the detection of added invert sugar, and the results obtained by Lund's test for protein- (precipitation with tannin) did not afford much evidence as to the purity of the samples of honey examined.w. P. s. Estimation of Lecithin in Medicinal Tablets. C. Virchow. (Chem. Zeit., 1912, 36, 906-907.)-A modification of a process described previously by the author {cf. ANALYST, 1911, 36,510) is recommended for the estimation of lecithin in tablets, in the so-called lecithin-albumin, etc. Two grms. of the substance are boiled with three successive quantities of 25 C.C.of absolute alcohol, the alcoholic extracts are filtered and evaporited together with a quantity of alcohol which is used for washing the extracted mass and the filter. The residue obtained after the evaporation of the alcohol is dried completely, and extracted with 20 C.C. of warm anhydrous ether, the ethereal extract being then evaporated, the residue weighed, and the phosphorus contained in i t estimated as described (Zoc.cit.). w. P. s.450 ABSTRACTS OF CHEMICAL PAPERS Estimation of Dirt in Milk. W. F. Lowe. (Chem. News, 1912, 106, 61-62.) -The dirt which is present in certain samples of milk usually consists of cow-dung, and several methods for its estimation have been proposed. I n experiments carried out by the author it was found that when cow-dung is added to milk, then separated by sedimentation, collected on a filter, washed, and weighed, the dry residue obtained only weighs about one-eighth of the weight of moist cow-dung added, I t was, however, ascertained as the result of further experiments that the volume of the sediment (in c.c.) was practically equal to the weight of the added cow-dung (in grms.), and the author, therefore, employs the following method for the estimation : Five hundred C.C.of the milk are thoroughly mixed and placed in a cylinder, the lower end of which is drawn out and attached by means of a piece of rubber tubing to a small glass tube graduated in 0.01 C.C. The bottom of this tube may be closed with a rubber stopper. After standing for about fifteen hours, the volume of the sediment is noted ; the sedi- ment is then removed from the tube and examined microscopically.I t will usually be found to consist of undigested vegetable fibre and tissue stained yellowish with bile, and the presence of bile may be proved by moistening the sediment with sugar solution, drying the mixture, and adding a drop of sulphuric acid. A red colour w. P. s.develops round the particles stained with bile. Preparation of Milk Serums and their Use in the Analysis of Milk. B. Pfyl and R. Turnau. (Arbeit. Kaiserl. Geszmdheitsamte, 1912, 40, 245-304.)-A serum which contains the albumin and globulin of the milk may be obtained by shaking 50 C.C. of the milk with 5 C.C. of carbon tetrachloride for ten minutes, then adding 1 C.C. of 20 per cent.acetic acid, again shaking the mixture, and submitting it to centrifugal action. When it is desired to prepare a serum free from coagulable proteins, the milk is heated in a flask on a boiling water-bath for twenty minutes, the flask being provided with a reflux apparatus; 50 C.C. of the heated milk are then treated as described above. The serums may be employed in place of those obtained by the use of calcium chloride, etc.(cf. ANALYST, 1907, 32, 117), over which they possess certain advantages. They are suitable for the determination of various physical and chemical constants in the analysis of milk, and afford a means of dis- tinguishing raw from heated milk. The serum obtained from heated milk does not yield a precipitate when again heated. w. P.s. Estimation of Suerose in Condensed Milk. H. Nowak. (Zeitsclz. anaL Chem., 1912, 51, 610-614.)-The method proposed recently by Jolles (cf. ANALYST, 1911, 36, 28) was found to be trustworthy; it depends on the fact that all mono- and disaccharides, with the exception of sucrose, are rendered optically inactive when they are heated with sodium hydroxide solution under certain conditions.The author finds that the most convenient and satisfactory method of carrying out the process is as follows : Five grms. of the condensed milk under examination are dis- solved in about 200 c . ~ . of water in a 250 c . ~ . flask, 10 C.C. of Fehling’s copper sulphate solution are added, the mixture is nearly neutraliaed with sodium hydroxide solution (it should still have a very faintly acid reaction), then diluted to the mark, and filtered.The lactose may be estimated in a portion of the filtrate in the usual way. AnotherFOOD AND DRUGS ANALYSIS 451 portion of about 100 C.C. of the filtrate is now treated with about 0-5 grm. (or more, if necessary) of potassium ferrocyanide, in order to precipitate the excess of copper, and again filtered. Fifty C.C.of this filtrate are placed in a Lintner’s pressure flask, 1.3 C.C. of a 16 per cent. sodium hydroxide solution are added, the flask is closed, and heated for forty-five minutes in a boiling water-bath. After cooling, 3.7 C.C. of basic lead acetate solution are added, the mixture is shaken, and filtered. The optical rotation of the filtrate is then observed in a 220 mm.tube. The reading multiplied by 0.75 gives grms. of sucrose per 100 C.C. of the filtrate, and the percentage quantity of the sugar is then calculated. The addition of the alkali and basic lead acetate increases the volume of the 50 C.C. of filtrate to 55 c.c., and the reading is conse- quently observed in a 220 mm. tube. For example, 5 grms. of a sample of condensed milk to which 40 per cent.of sucrose had been added, when treated as described above, gave a reading of + 1.06” corresponding with 39.75 per cent. of sucrose. w. P. s. Direct Determination of Sucrose in the Presence of Reducing Sugars. W. E. Cross and W. G. Taggart. (Intern. Sugar J., 1912, 14, 444-448; through J. SOC. Chem. Ind., 1912, 31, 831.)-As a more rapid means than the Clerget inversion procees of determining the sucrose content of sugar-factory products containing reducing sugars, Jolles (ANALYST, 1911, 36, 28) has recommended destruction of the rotatory power of the dextrose and lcevulose by sodium hydroxide.Using samples of cane sugars and molasses the authors obtained much lower results than the Pellet- Lemeland process with the Clerget-Herzfeld inversion method, the differences varying from 2 to 14 per cent., and determinations made with pure solutions of sucrose, dextrose, and lcevulose, in the proportions obtaining in cane molasses confirmed these figures.Experiments were afterwards made for the purpose of modifying the process to obtain more trustworthy results. As finally elaborated the procedure now recommended is as follows: Fifty C.C.of the “norma1” sugar solution are transferred to a 100 C.C. flask, 6.3 C.C. of sodium hydroxide solution (sp. gr. 1.332) and 7.5 C.C. of hydrogen peroxide (100 vol.) added, and the mixture cooled to present eifervescence. The flask is then immersed in a water-bath a t 55” C. for twenty minutes, after which the liquid is cooled, acidified with acetic acid, made up to the mark, clarified with dry basic lead acetate, filtered, and polarised, using preferably the 400 mm.tube. I t is stated that the solution thus obtained is almost colourless and quite bright. On applying (a) this modification, and com- paring the results with ( b ) the Clerget-Herzfeld process, satisfactory results were obtained, some of these being as follows : Syrup (a) 32-40, ( b ) 31.87 ; open-kettle molasses (a) 41.12, (b) 40.98 ; molasses (a) 28.40, ( b ) 27-93 per cent.As this method has been found so reliable in the authors’ hands, they recommend it as a substitute for the Clerget-Herxfeld inversion method in the analysis of eyrups and molasses, and especially as a routine method for the determination of the sucrose content of low-grade products in hot-room goods.Estimation of Essential Oil in Preparations of Mustard. H. P6nau. ( J . Phtarm. Chim., 1912, 6, 160-164.)-Estimation of essential oil in mustard by the452 AESTRACTS OF CHEMICAL PAPERS silver sulphide gravimetric method is unreliable, results differing by 16 per cent. being obtained with the same sample of mustard. The following modification of the French Codex method was found to be the most accurate of any : Five grms.of the mustard are digested with 100 C.C. of water in a closed flask for six hours, after which 20 C.C. of alcohol and 20 C.C. of poppy-seed oil are introduced, and the flask thoroughly shaken. The liquid is then vary slowly distilled on a glycerol bath, and 90 C.C. of the distillate collected in a, flask containing 10 C.C.of 50 per cent. ammonia solution. After the addition of 20 C.C. of TG silver nitrate solution, the flask contain- ing the distillate is closed, and left in the dark for twenty-four hours, the precipitate being then rapidly filtered off, and washed with water. The filtrate is slightly acidified with nitric acid, the silver precipibated with 1 C.C. of ;k hydrochloric acid, and the precipitate dried on counterpoised filters and weighed.The excess of silver may also be estimated volumetrically by the potassium cyanid2 method, though the results are not so good as by the gravimetric method (error in five estimations of ally1 mustard oil = 2.4 per cent.). Volumetric estimation of the silver with ammonium thiocyanate is inaccurate (error in five estimations = 5.1 per cent.).(Cf. ANALYST, 1912, 309.) C. A. M. Methods of Estimating Nicotine in Tobacco and Tobaceo Extracts. J. Toth. (Chern. Zeit., 1912, 36, 937-938.)-The silico-tungstic acid method of Bertrand and Javillier (ANALYST, 1909,34,219) gives results in close agreement with those given by the methods of the author and of Kissling. The following modific- ation of the method was used : Ten grms.of the dried powdered tobacco are digested for fifteen to twenty minutes on the water-bath with 100 C.C. of 0.5 per cent. hydro- chloric acid, then centrifuged and decanted, and the residue treated similarly three times. To the solutions thus obtained are added 10 to 20 per cent. of silico-tungstic acid or potassium siiico-tungstate, and the precipitated nicotine silico-tungstate separated in the centrifuge. After standing for one or two days the precipitate is taken up in a little dilute hydrochloric acid, mixed with the reagent, and again separated.I t is next mixed with ignited magnesia, and heated in a current of steam, and the nicotine in the distillate titrated, using iodeosin as indicator. The method is particularly useful for estimating nicotine in the presence of ammonia or pyridine bases, none of which are precipitated by silico-timgstic acid from a hydro- chloric acid solution, (Cf.ANALYST, 1911, 36, 106, 143, 279, 348, 544, 545.) C. A. M. Solidified (Hydrogenised) Oils. A. Bomer. (Zeeitsclz. Untersuch. Nahr, Genussm., 1912, 24, 104-112.)-During recent years many processes for solidifying oils have been patented, and these methods consist essentially in subjecting the oil to the action of hydrogen in the presence of a catalyst.According to the claims of the patentees the catalysts employed may be metals (such as nickel, platinum, palladium, etc.) or metallic oxides in a fine state of division. The solidifying process is carried on to any desired extent according to the consistence desired in the finished product.For instance, earthnut oil may be hydrogenised until it resembles tallow, or, by a shorter period of treatment, it may be converted into aFOOD AND DRUGS ANALYSIS 453 product which cannot be distinguished from lard as regards its appearance, consistence, taste, smell. The process results in the conversion of the unsaturated fatty acids (oleic acid, etc.) of the oil into stearic acid ; the iodine value is diminished to a very considerable extent, and the melting and solidifying points raised. For example, solidified earthnut oil may have an iodine value as low as 424 and sesame oil 25.4, these being the results obtained by the author on the examination of some of the products.The phytosterol present in vegetable fats is not altered by the treatment, and the phytosterol acetate test described previously by the author enables a solidified vegetable oil to be distinguished from an animal fat yielding similar chemical and physical constants.w. P. s. Estimation of Succinic and Malic Acids in Wine. C. von der Heide and E. Sehwenk. (Zeitsch. anal. Chem., 1912, 51, 628-638.)-Slight modifications are made in the methods described previously by von der Heide and Steiner (cf.ANALYST, 1909, 34, 278, 279). In the case of succinic acid, the ethereal solution obtained at the end of the process (Zoc. cit.) is evaporated after the addition of water, and the residual aqueous solution is rendered alkaline with barium hydroxide. The mixture is then heated on a water-bath for ten minutes, the excess of barium is removed as carbonate, the mixture is cooled, filtered, and the filtrate titrated with silver nitrate solution.I t is recommended that at least two hours should elapse after the addition of the silver nitrate, and before the excess of the latter is titrated. For the estimation of malic and succinic acids together, 100 C.C. of the wine are evaporated to a volume of 20 c.c., and in this residual liquid the tartaric acid is separated and estimated.The filtrate from the potassium hydrogen tartrate precipitate is treated as described (Zoc. cit.), but, after the ether has been evaporated from the ethereal extract, the residue is treated with barium hydroxide, and the solution containing soluble barium salts of the two acids is evaporated, the residue ignited, and titrated.The alkalinity gives the sum of the quantity of succinic and malic acids present. w. I?. s. Estimation of Phosphoric Acid in Wines. C. von der Hiide and J. Schwenk. (Z&tsch. anal. Chem., 1912, 51, 615-627.)-As regards the alleged loss of phosphoric acid during the ignition of the total solids of wine, the authors find that no such loss takes place, and that in the case of ordinary table wines, sweet wines, musts, and yeast, the addition of sodium carbonate and potassium nitrate previous to the ignition is quite unnecessary. I n preparing the ash of the wine for the estimation of the phosphoric acid, it is recommended that 60 C.C. of the sample be evaporated, and the residue incinerated ; the carbonaceous mass is then extracted with water, and the washed carbon is ignited to a white ash, which is dissolved in nitric acid and the solution added to the aqueous extract. This solution is used for the estimation of the phosphoric acid, for which purpose the method proposed by von Lorenz (Landw. Versuchsst., 1901, 55, 183; cf. ANALYST, 1903, 28, 229) is recommended. Grete’s method (ANALYST, 1909, 34, 541) is also trustworthy, and may be employed for estimating the total phosphoric acid directly-that is, without previously incinerating the wine residue. The amount of organically combined phosphoric acid in mine is only a small proportion of the total phosphoric acid ; it454 SBSTRACTS OF CHEMICAL PAPERS may be estimated by the method described by Philippe and Duperthius (Mitt. a. d. Geb. der Lehensmittelunters. u. Hyg., 1910, 1, 125), which depends on the precipita- tion of the inorganic phosphoric acid by means of barium hydroxide, the barium salts of the organically combined phosphoric acid being soluble in water. w. P. s.

ISSN:0003-2654    

DOI:10.1039/AN9123700446

出版商:RSC    

年代:1912

数据来源: RSC

摘要:

454 SBSTRACTS OF CHEMICAL PAPERS BACTERIOLOGICAL, PHYSIOLOGICAL, ETC. Studies of Amylases. IV. A Further Investigation of the Properties of Pancreatic Amylase. H e C. Sherman and M. D. Sehlesinger. (J. Amer. Chem. SOC., 1912, 34, 1104-1111,)-1n a previous paper ( J . Amer. Chem. SOC., 1911, 33,1195) the authors describe preparations of purified pancreatic amylase, having an activity of about 5,000 on Lintner’s scale for purified diastases.A detailed method of preparing such amylase is described with modifications suggested by recent work, the preparation having a heat of combustion of 5,568 calories per grm., and the following approximate composition, C 51.9, H 6.6, N 15.3, S 1.0, P 0.8, 0 (and undetermined) 24-4. Coagulation occurs a t 70’ C. In the determination of diastatic activity it was at first found that the yield of reducing sugar did not amount to more than 85 per cent.of the starch used, but, on increasing the amount of enzyme and allowing it to act on relatively small amounts of starch, such as 20 mgrms. of enzyme to 100 C.C. of 1 per cent. soluble starch for seventy-two hours, the resulting sugars were found to be a mixture of maltose and glucose, and confirmed by a special quantitative modification of the osazone method.The method of purification of the pancreatic-amylase had thus resulted in a concentration of a glucase or maltase in addition to the amylase. I n the absence of electrolytes, the preparations very rapidly lose their enzymic activity, and even in the presence of salt and phosphate, as used for the determination of diastatic power, the purified amylase deteriorated from 33 to 50 per cent.in twenty-four hours, the commercial pancreatins being much more stable. This was thought to be due to the presence of a protease of a trypsin- like character, which might digest the protein with which the amylase was associated. I t was found on measuring the proteolytic activity of both the crude pancreatin and the purified amylase prepared from it, that the increase in activity of both enzymes was about proportional, Other preparations examined showed much higher pro- teolytic activity with an amylolytic action only one-fifth as great.I t is possible that one of the pancreas enzymes is both a protease and amylase, with the potentiality of an increase in the one activity accompanied by a decrease in the other.H. F. E. H. Note by Abstracter.-The formation of glucose, if it occurs, of coursevitiates the Lintner value for diastatic activity, since this value is an expression of the activity of the enzyme in terms of maltose produced. The fact that in some cases the “R” (=per cent. of maltose) does not exceed 100 does not rule out the possibility of glucose having been formed simultaneously with or at the expense of the maltose.Chemieal Detection of Blood in Blood-Stains. E. Schar. (Pharm. J., 1912, 89, 157-158.)-1n cases where the quantity of suspected material is too smallBACTERIOLOGICAL, PHYSIOLOGICAL, ETC. 455 for spectroscopic examination, or for the preparation of haemin crystals, the author employs several of the well-known colour-reactions based on athe action of blood upon hydrogen peroxide in presence of oxidisable substances forming coloured oxidation- products.The blood, in solution, is mixed with the solution of oxidisable substance and either hydrogen peroxide, or turpentine oil previously shaken with water in the presence of air. The tests are : (1) tincture of guaiacum, which yields a blue colour ; (2) tincture of aloes (isobarbaloin), a raspberry-red colour ; (3) Adler's test with an acetic benzidine solution, a greenish-blue ; (4) Adler and v.Fiirth's leucomalachite green test, giving a dark green; (5) and the author's test with hydroccerulignone, yielding the scarlet-coloured ccerulignone. Certain inorganic substances (iron and copper salts) and substances containing enzymes of the '( peroxydase ') class give similar reactions, but these may be ruled out, in the first instance (inorganic substances), by control reactions, and secondly, as regards interfering enzymes, by first heating the material for a short time from 80Oto 100" C.I n any case, a negative result may be considered as proof of the absence of blood.According to the author, the best method of preparing the blood solution for the tests, whether from old or recent stains, is by means of chloral hydrate. The spot or stain is first moistened with a drop of acetic acid, and then soaked for one to several hours in chloral hydrate solution of 70 to 80 per cent. strength. The blood solution may then be used for the above tests.Zone reactions may be carried out by dissolving a little of the solutions of one of the oxidisable matters in the chloral hydrate solution of the blood, and carefully adding a quantity of hydrogen peroxide solution (3 per cent.), diluted with twice its volume of alcohol and slightly acidulated with acetic acid, by superposition. A deeply-coloured zone will appear between the two strata in the presence cf blood, and will gradually spread into the liquids. When pyridine is used for the extraction of blood from stains, etc., the colour-reaction is accelerated and intensified.A. R. T. Physico-Chemieal Method for Determining the Changes taking place in Meats. 0. von Furth and E. Lenk. (Zeitsch. Untersuch. Nah?: Genussm., 1912, 24, 189-197.)-When flesh is immersed in a 15 to 25 per cent.sodium chloride solution it gradually diminishes in weight, but this only holds good for flesh one day old, counting from the death of the animal from which it was obtained. I n the case of flesh more than one day old, an increase in weight is observed during the first ten to fifteen hours it is immersed in the salt solution, and this increase is always followed by a decrease during the succeeding hours.Chilled beef rapidly increases in weight when placed in sodium chloride solution. The increase in weight is probably due to the formation of lactic acid, as acids, when not above certain con- centrations, greatly accelerate the imbibition capacity of muscular tissue, etc. ; the subsequent decrease in weight appears to be due to a coagulation of the proteins, It is suggested that when the subject has been further investigated the phenomenon may be of use in testing meats.w. P. s. Quantitative Estimation of Quinine in Urine and in Blood. A. Baldoni. (Arch, d. Farmacol. sperim., 1912, 13, 324-353 ; through Chena. Zentralb., 1912, IT.,456 ABSTRACTS OF CHEMICAL PAPERS 554.)-An experimental examination of the methods of Gordin (Ber., 1899, 32, 2843), Kleine (Zeitsch.f. Hyg.- u. Infect.- Krankh., 1901, 38, 458), Gaglio (Atti per gli studi del. Malaria, 1905, 6, 77), and Nishi (Arch. f. exp. Pathol. u. Pharrnak., 1909, 60, 312). The method of Nishi was found to give results which were uniformly some- what low, whilst the method of Kleine showed errors somewhat beyond the permissible limit, and not all in the same direction.The results obtained. by the methods of Gordin and Gaglio agreed closely with each other and with the amount of quinine actually present. Making use of these methods, the author was able to show that the resorption of quinine is more rapid when it is administered by the mouth than when administered hypodermically. Quinine disappears from the blood in a very few hours, and in no cme could it be detected twenty-four hours after administration, a statement which conflicts with that of De Luca (Arch.d. Farmacol. sperim., 1901, 2, 390). G. C. J. Iodine Content of Thyroid Glands. N. H. Martin. (Pharm J., 1912, 89, 144-145.)-The following analyses of sheeps’ thyroid glands, normal in size, are given : Date. 1911.July ... August ... September.. . October . . . November . . . December . . . 1912. January ... February ... March ... April ... June ... ... May Numbei of Glands Used. 590 885 490 490 190 253 216 184 393 958 830 1,081 5,560 Weight of Fresh Glands. Grnis. 787 1,096 631 584 243 408 320 289 618 1,580 1,459 1,284 3,299 Weight of T?LyroZ’- deunz siccrom Obtained. Grms. 195 235 200 162 54 72 64 60 171 611 487 426 2,737 Average Weight of Each Fresh Gland.Grins. 1.33 1.24 1.29 1.19 1.28 1.61 1-48 1-57 1.57 1.46 1.52 1.55 1 *42 Average Yield of SiCCUlIZ per Gland (:rills. 0.33 0.27 0-41 0-30 0.28 0.28 0-29 0.33 044 0.57 0.51 0-51 0.38 Iodine in ,S’icc,lm2. Per Cent. 0 -40 0-36 0.34 0.38 0.30 0.34 0.32 0.32 0.34 0.30 0.34 0.38 Iodine on Fresh Weight. Per Cent.0.099 0.077 0.107 0.105 0.066 0.060 0.064 0.066 0.095 0.116 0,113 0,126 Average Iodine per Gland, Grms. 0.00132 0.00095 0.00138 0.00125 0*00085 0*00097 0.00095 0.00104 3.00149 3.00169 3.00172 3-00195 ~ 1.00129 The author has examined glands having the enormous weights of 12.0, 14.0, and 32.5 grms., containing 0.22 per cent., 0.20, and 0.08 per cent. of iodine in the thyroideupn siccum, and 0.00616, 0*00660, and 0*00600 grms.iodine per gland respectively. Thus the larger amount of iodine in these glands was not proportional to their increased weight, and the percentage of iodine in the dry substance was reduced. The figures, as a whole, lend no support to the statement that the amount of iodine in the dry substance is greater in the winter months. A. R. T.BACTERIOLOGICAL, PHYSIOLOGICAL, ETC.457 Measurement of Relative Tryptic Activity. A. R. Smith. (Pharm. J., 1912, 89, 137-139.)-The author has applied the method of Sorensen (Compt. rend. Trav. du Lab. de Cadsberg, 1907, 7, 1) to the determination of the relative tryptic activity of certain pharmaceutical preparations. The method is based on the facts that the main products of the hydrolysis by trypsin are amino-acids, and that if the basicity of the amino-groups be neutralised, the carboxyl-groups can be titrated in the usual way.Schiff has shown that these amino-groups can be converted into neutral methylenic groups by adding formaldehyde, and the acids can then be estimated by titration. The reaction with formaldehyde is reversible in presence of water, but an increase of formaldehyde or decrease in the amount of water present tends to make the reaction proceed in the desired direction.The tests are carried out as follows: A 4 per cent. solution of casein is pre- pared by dissolving the substance in recently-boiled and cooled water containing 30 C.C. of The solution is made neutral to phenol- phthalein with alkali before making up to volume, and a little chloroform is added as an antiseptic.Twenty-five C.C. of this casein solution at 55" C. is mixed with a known volume of the trypsin-containing solution at the same temperature, and water added (55" C.) to make the volume to 50 C.C. One grm. of the enzyme pre- paration to be tested is triturated in a mortar with a little chloroform-water, and the solution made up to 100 C.C. After standing one hour, 1 C.C.of the well-mixed, unfiltered solution is added to the 25 C.C. of casein solution at 5 5 O C., and the mixture diluted as stated. The mixed solutions are kept at this temparature for twenty minutes, when 20 C.C. of the liquid is removed, and titrated with sodium hydroxide solution after first adding 10 C.C. of neutral formaldehyde solution.(This solutioii is prepared immediately before use by mixing 1 C.C. of a $ per cent. solution oE phenolphthaleln in 50 per cent. alcohol with 50 C.C. of 40 per cent. formaldehyde solution, and adding Sorensen recommends that the titration of the '' digest " solution should be carried on till the liquid is the same colour a8 a control prepared by adding 10 C.C.of the formaldehyde reagent to 20 C.C. of water and 5 C.C. of caustic soda. The solution is titrated back with hydrochloric acid till just pink, when 1 drop of standard alkali makes it distinctly pink, and 2 drops, red. A blank experiment must be made by titrating 20 C.C. of the mixed casein and trypsin solutions before digesting, in order to ascertain the volunie of alkali required.The difference after digestion is that due to the acids produced in the hydrolysis. The figure multiplied by 100 may be used to express the relative activity of trypsin preparations. Further experiments with the method showed : (I) That relative measurement of activity can be made so loug as not more than 3-5 to 3.7 C.C. of alkali are used in the titration of 20 C.C. of the '' digest " ; (2) that 56" C. is the optimum tempera- ture for digestion; (3) that under conditions (1) and (2) a period of twenty minutes for digestion is convenient, since then the relative hydrolysis is in direct proportion to the trypsin present. The following figures were obtained by using this method on certain preparations : sodium hydroxide per litre. sodium hydroxide till the colour is just pink.) This is the end-point.458 ABSTRACTS OF CHEMICAL PAPERS Blank. Sample. Tryptic Activity. ... ... Pancreatin 1 ... ... ... ... 9 9 2 9 9 3 9 9 4 >> 5 ... ... ... ... ... ... ... ... ... ... ... Trypsin 1 ... ... ,, 2 ... ... ... ... Titration. 3.45 2.76 4.02 3.64 3-42 3.34 3.78 C.C. NaOH 5. I I 2.08 2.04 2-05 2-08 2.05 ,2-06 2.06 1-37 0.72 1.97 1.56 1.37 1-28 1.72 A. R. T.

ISSN:0003-2654    

DOI:10.1039/AN9123700454

出版商:RSC    

年代:1912

数据来源: RSC

摘要:

458 ABSTRACTS OF CHEMICAL PAPERS ORGANIC ANALYSIS. The Coagulation of Albumin by Heat and its Precipitation by Mercuric- Potassium Iodide. Gravimetric and Volumetric Estimations. L. Vallery. (Compt. rend., 1912, 155, 417-420.)-1n a previous note (Compt. Tend., 1911, 153), the author showed that the coagulation of albumin in urine by heat in presence of acetic or trichloracetic acid is incomplete, and he described a new gravimetric method for its estimation, based on the use of Tanret’s or Esbach’s reagent, giving distinctly higher results. I t is now shown that the deficiency in the quantity of albumin coagulated by heat is due to the partial hydrolysis of the albumin by the action of the acid, and the loss when acetic acid is used is always less than when trichloracetic acid is present, owing to the greater degree of dissociation of the latter. It is now found that if a non-dissociated acid-e.g., normal caproic acid--be employed, perfectly satisfactory results are obtainable without appreciable hydrolysis. A few drops of this acid are to be added to the sample after this has been neutralised with sodium hydroxide in presence of phenolphthaleln, but without the addition of an electrolyte.This procedure is especiaily recommended in the analysis of urine. The volumetric estimation of albumin by the use of Tanret’s reagent depends on an adsorption reac- tion with mercury which can be represented by a hyperbolic formula. In the case of serum and egg albumins this law is expressed by the equation log. ---- --- = K ; where x= the quantity of albumin, H = the initial quantity of mercury, h = the quan- tity of mercury adsorbed, and K is a constant.By making H= 0-20 grm. and dilut- ing to 200 C.C. after precipitation, the value of K is 0.54 for serum albumin and 0.52 for egg albumin. The presence of urea and sodium chloride is without influence on the curve, but the presence of phosphates lowers the constant considerably, to an extent depending on their quantity.For this reason thevolumetric process is not a t present applicable for urine and other organic fluids containing more phosphates than serum and egg albumins. 1 H x E - h J. F. B. Benzoic Acid as an Acidimetric Standard. G. W. Morey. (J. Arner. Chem. Soc., 1912, 34, 1027.)-A hydrochloric acid solution was standardised by theORGANIC ANALYSIS 459 distillation method of Hulett and Bonner (J.Amer. Chem. Soc., 1909, 31, 390), by the gravimetric silver chloride method, against sulphuric acid standardised gravi- metrically by precipitation as barium sulphate and volumetrically against sodium oxalate, and was finally standardised against benzoic acid. The methods used are described in detail.The benzoic acid was prepared by recrystallising pure samples, twice from alcohol and once from water, subliming in vacuo, fusing at 140° C., and casting into sticks. About 1 grm. was weighed, placed in a 300 C.C. flask, swept free frorn carbon dioxide, dissolved in 20 C.C. of alcohol, and titrated with FG alkali, 3 drops of 1 per cent. phenolphthaleyn being used as indicator, and air, free from carbon dioxide, being led through the liquid.A correction for the effect of the alcohol on the end-point was applied. The appended table shows the accuracy of the benzoic acid method : Method. TG factor for HC1. ... ... 0-9980 Direct by Hulett ... ... ... Direct by AgCl ... ... ... ... ... 0.9984 H2S0,-BaS0,-NaOH-HC1 ... ... ... 0.9984 H,S0,-Ns,C20,-NaOH-HC1 ...... ... 0-9982 C,H,CO,H--NaOH-HCl ... ... ... ... 0-9981 C,H,CO,H-Ba( OH),-HC1 ... ... .,. 0.9984 Its stability and lack of hygroscopicity make it convenient, and the method involves only a single weighing and a titration. 0. E. M. Estimation of Carbon by Moist Combustion. H. Simonis and F. H. Thies. (Chem. Zeit., 1912, 36, 917-918.)-The following method is recommended for the estimation of carbon in such substances as phenylacetaldehyde, etc., the oxidation being carried out by means of potassium bichromate and sulphuric acid.A portion of about 0.2 grm. of the substance is weighed into a small platinum boat, which is then filled with powdered potassium bichromate and introduced into a round-bottomed flask of about 200 C.C. capacity. A further quantity of 20 grms.of bichromate are placed in the flask, which is then closed with a stopper through which pass the stem of a tapped funnel and a delivery-tube. The latter connects with a wide tube filled with glass-wool in which most of the moisture leaving the flask is coridensed; the other end of the wide tube is in communication with a combustion-tube filled with copper oxide and heated by suitable meaus.The necessary drying and absorption apparatus are attached to the end of this combustion-tube. I t is essential that the gases leaving the oxidation-flask be passed over hot copper oxide, as they contain small quantities of unoxidised carbon compounds. At the commencement of the .operation, a soda-lime tube is attached to the combustion-tube in place of the absorption apparatus, and a current of oxygen is passed through the whole apparatus, fhe supply of oxygen being introduced through a T-piece and narrow tube which extends through the delivery-tube to the bottom of the flask; oxygen is also supplied to the top of the funnel which contains sulphuric acid.When the apparatus has been filled with oxygen the absorption apparatus is connected, and the sulphuric acid is admitted frorn the funnel, drop by drop, or at such a rate that the evolved gases pass through the absorption vessels at the rate of a few bubbles a second.460 ABSTRACTS OF CHEMICAL PAPERS The contents of the flask are eventually heated with a burner for thirty minutes, and pure air is passed through the apparatus before the absorption vessels are weighed.Duplicate estimations of carbon in phenylacetaldehyde yielded 79.98 and 79.96 per cent. of carbon, respectively, against 80 per cent. required by theory. w. P. s. Methods for Determining Neo- and Allo-Chlorophyll in the Presence of one Another. C. A. Jacobson and L. Marchlewski. (Anzer. Ckent. J., 1912, 48, 111-124.)-The authors have shown previously (Anzcr. Chem.J., 1911, 47, 221) that the ratio of neo-chlorophyll to allo-chlorophyll in plants is not a constant one, varying not only in different species, but in the same when the samples have been grown under different conditions. Metlzod 1.-Using ultra-violet spectrum. Neo-chlorophyllan was prepared by two methods in order to obtain a photograph of the ultra-violet spectrum of this material in the pure state.By the shorter method the starting-point is chlorophyllan and the neo-chlorophyllan so obtained is a black, amorphous substance something like oak bark. I t gives a deep, olive-green solution, thus distinguishing it from allo-chlorophyllan which has a reddish-brown colour. The ultra-violet spectrum in a concentration of 0*00004 grm. per C.C. of chloroform shows three absorption bands, the wave-lengths in a layer of 6 mm.thickness being (1) h 365.0 to 382.7, (2) h 388.8 to 405.0, (3) X 407.4 to 426.5. By the second and longer method of preparation, the neo-chlorophyllan is ex- tracted directly from leaves by the use of organic solvents alone and remains in solution in carbon disulphide, while the allo-chlorophyllan is removed by continuous alcoholic extraction.The ultra-violet spectrum is identical with that obtained by fhe first method. A series of eleven photographs is supplied showing the ultra-violetl spectra of artificial mixtures of the neo- and allo- varieties in different proportions equally graded, and the method consists in preparing the chlorophyllan of the plant to be examined in the ordinary way, and then to take a photograph in the ultra- violet of the spectrum yielded by a solution whose concentration is equal to those photographed in the series.A direct comparison with the plates supplied will then reveal the composition of the mixture to within 2 per cent. Care must be taken, first to remove all the yellow colouring matters by means of several precipitations with alcohol from the concentrated chloroform solution before photographing the spectrum, except in the case of Acer platinoides, whose yellow colouring matter was found not to interfere.Method 2 is based on the extinction co-efficients of the chloroform solutions, and has already been employed by one of the authors for determining the total green colouring matter in a plant. A cadmium lamp was employed, giving true mono- chromatic light in the green part of the spectrum.A table is given of the same eleven artificial mixtures as given above with their extinction co-efficients, for cadmium light h = 508 pp and sodium light h = 589 pp. The values for both lights are plotted and yield practically straight line curves, and show that the percentage composition of any mixture of neo- and allo-chlorophyllan is a linear function of its extinction co-efficient.The first method is less sensitive to impurities, is more adapted to practical application, and can be used in very small quantities, but whereORGANIC ANALYSIS 46 1 sufficient material is available to allow of very thorough purification, the extinction method allows of greater accuracy. H.F. E. H. Estimation of Cineol in Volatile Oils. F. D. Dodge. (J. Ind. and Eng. Chem., 1912, 4, 592-593.)-The author oxidises the terpenes and unsaturated com- pounds in the cold with potassium permanganate, and measures the remaining insoluble cineol. For the test 10 C.C. of the oil (eucalyptus, cajeput) are treated in a flask of 500 C.C. capacity with potassium permanganate solution (5 to 6 per cent.) added in small quantities, with shaking, till the reagent is no longer reduced.The flask must be kept in ice-cold water throughout the addition of the permanganate, of which from 100 to 400 C.C. are required. When excess has been added, the mixture is kept cold for twelve to eighteen hours with occasional shaking. The precipitated manganic oxide is then dissolved by sulphurous acid and the flask filled with water, the unoxidised oil collecting in the narrow neck.The oil is then transferred by a capillary pipette to a graduated tube, washed with a little alkali and its volume read off. The cineol should have the following characters : Sp. gr. 15" C., 0.929 to 0.930 ; be optically inactive ; soluble in 34 volumes of 60 per cent.alcohol at 25" C . The isolation of the cineol itself allows of a, determination of its purity, or of a detection of other compounds when present with it. Thus camphor, fenchone and bornyl acetate increase the sp. gr. of the residual oil and show optical rotation; inactive camphor increases the sp. gr. ; petroleum products lower the sp. gr. and diminish the solubility ; borneol and menthol are oxidised to camphor and menthone respectively ; and menthone lowers the gravity and shows optical activity.A. R. T. Detection and Estimation of Halides in the Presence of Cyanides by Means of Formaldehyde. K. Polstorff and H. Meyer. (Zeitsch. anaZ. Chem., 1912, 51, 601-609.)-The method is based on the fact that formaldehyde combines with potassium cyanide to form a compound which does not reduce silver nitrate or yield a precipitate with the latter in the presence of nitric acid; Romijn has previously made use of this reaction for the estimation of formaldehyde (ANALYST, 1897,22,221).For the detection of chlorides in mixtures of the same with cyanides, a solubon of the salt is rendered alkaline with potassium hydroxide and formaldehyde is added in excess ; the solution is then acidified with nitric acid and tested with silver nitrate when the formation of a white, curdy precipitate which is soluble in ammonia indicates the presence of chlorides.For the estimation of chloride, bromide, or iodide in the presence of cyanide, a quantity of about 0.6 grm. of the sample is dissolved in 100 C.C. of water, the solution is rendered alkaline with potassium or sodium hydroxide, and 30 drops of a 35 per cent.formaldehyde solution are added. After the lapse of a few minutes, the mixture is acidified with nitric acid, and the halide is titrated according to Volhard's method. The cyanide may he estimated in a separate portion of the sample by Liebig's method. w. P. s. Estimation of Halogens in Organic Compounds, including a Device for the Combustion of Volatile Substances.E. E. Reed. (J. Amer. Chem. SOC. 1912, 34, 1033.)-The substance containing halogen is subjected to combustion in a462 ABSTRACTS OF CHEMICAL PAPERS quartz tube, for the arrangement of which the original should be consulted, and the halogen arrested by means of silver powder and silver oxide. The silver is weighed in a silver boat, and the separately weighed silver oxide (0.2 to 0.5 grin.) then added.The silver oxide is prepared from silver nitrate, washed, dried at 100" C., well mixed, and sealed up in 0.5 to 1.0 grm. portions. The loss on reduction is determined by heating a portion in hydrogen from 160' to 170' C. for thirty minutes. I t is higher than the theory demands, on account of retention of water by the silver oxide ; this is of no consequence if it is uniform.During the combustion the silver and silver oxide is maintained at about 270" C., and when it is finished, reduced by hydrogen at 170" C. In the calculation the loss in weight on reduction of the ,quantity of oxide used is deducted from the original weight of the boat. I n the device for the combustion of volatile liquids (cf.original) the substance sealed in il, bulb is placed in the larger limb of a U-tube communicating with the heated com- bustion tube into which its vapour is swept, after the bulb has been broken, by means of a, current of air or nitrogen. A table shows that analyses are consistent and sufficiently accurate, and that 0-2 to 0-25 grm. of substance, but not m.ore, may be burnt in twenty minutes.0. E. M. Analysis of Hydrocarbon Mixtures. 0. Routala. ( A m . Acad. Sci. Fenniccz, 1912, Ser. A, 2, 19; through Chem. Zentralbl., 1912, IT., 638.)--The iodine value for mineral oils and their derivatives has only a, significance when accompanied by an exact description of the conditions under which the estimation was carried out.I n the estimation of ethylenic hydrocarbons in mixtures, the results deduced from the iodine value vary according to the method employed, the time of action, the temperature, and the quantity of iodine solution; these should always be specified. The bromine value, estimated according to Frank's method, affords a quantitative measure of the ethylenic hydrocarbons, and is particularly to be recommended when the quantity of the sample is small, for the determination of the degree of refining of colourless or slightly coloured mineral oil products, and for testing the purity of particular fluid ethylenic hydrocarbon preparations. The percentage of ethylenic hydrocarbons can be calculated direct from the bromine value by the formula A = [K + (n - 5)c].G, in which A = the percentage of ethylenes ; K = a constant ; n= the mean number of carbon atoms (not less than 5) in the ethylenes corresponding to the particular limits of boiling-point ; and G is the bromine value.G=Lo2= !?EE8, in which g is the quantity of bromine absorbed in grms., S is the quantity of the substance taken in grins., and w=c.c. of Tc bromine solution. The constants K and c are calculated for each hydrocarbon, so that K is 0.4375 for arnylene, 0.5950 for hexylene, percentage of ethylenes bromine value 0.6075 for heptylene; for each increment of CH, the constant increases on the average by 0*0875=c.For instance, in a, mixture of arnylene and isopentane of sp. gr. 1 5 O C. =0*6424, a quantity of 0,2277 grm. of the sample required 39.5 C.C. of a & bromide-bromate solution, corresponding to 0,3160 grm.of bromine ; the bromine number is thus 138, and the sample contains 0.4375 x 138= 60.37 per cent. of S S = a constant. -ORGANIC ANALYSIS 463 Undecylenic acid, CH,:CH.(CH,),.COOH, . . Crotonic acid, CH,.CH:CH.COOH 2--3 Oleic acid, CH,(CH,),,.CH:CH.COOH . .. 2-3 Hypogaeic acid, CH,(CH,),,.CH:CH:COOH amylene. by those of the sulphuric acid method.The accuracy of the results obtained by the bromine method is confirmed J. F. B. 135.1 137.3 - 137.8 17.4 10.3 4.3 295.0 6.6 20.4 1.9 99.8 8.7 18.0 3.0 89.7 Relationship between the Iodine Value and the Structure of Acids of the Oleic Series. G. Ponzio and C. Gastaldi. (Gaez. Chinz. IttaZ., 1912, 42, 92-95.)-While the iodine value of ordinary oleic acid as estimated by the usual lnethods is in close agreement with the theoretical value, the results obtsined with crotonic acid and certain other fatty acids are much too low.Thus in the estimn- fion of the iodine value by the methods of Hiibl (4 hours' absorption), Wijs (30 minutes) and Hanus (30 minutes) the following results were obtained : From these and similar results the conclusion is drawn that it is the position of the double bond in unsaturated acids of the series CnH,n -- 20, that influences the amount of the iodine value.If the double bond is distant from the carboxyl group, as in ordinary oleic and undecylenic acids, the iodinevalue will be normal, whilst if it adjoins the carboxyl group, as in the case of the other acids in the table above, the iodine value will be lower than the theoretical value.Further experiments showed that it was only the velocity of the reaction that was affected by the position of the bond ; for by prolonging the time of absorption to seventy hours, 2-3-oleic acid gave an iodine value of 45.9 by Hanus' method, and of 86.8 by the method of Wijs. The absorption was due to addition and not to substitution.I t thus appears that an estimation of the iodine value is a good method of establishing the position of the double bond in an unsaturated acid. C. A. M. Proximate Analysis of Corn plex Lipoids by Alcoholysis. Fourneau and Piettre. (BdZ. SOC. Clzim., 1912, 11, 805-810.)-The authors have studied the separation of complex fatty bodies into their proximate constituents by the action of alcoholysis.The material used was lecithin containing 1.76 per cent. of nitrogen and 3-86 per cent. of phosphorus. &4 solution of 50 grms. of lecithin in 100 grms. of methyl alcohol was saturated at a temperature of 0" C. with gaseous hydrogen ahloride. The solution was then heated at about 50" C. for one hour until the excess of hydrochloric acid had disappeared. The liquid then separated into two layers, the upper containing the esters of the fatty acids, and the lower containing the glycero- phosphoric acid and choline hydrochloride.The upper layer was carefully decanted off, and washed with a little water, the washings being added to the aqueous acid layer, which latter was then exhausted with ether to remove the last traces of fatty matters. The ethereal extract was added to the fatty eshers previously separated,464 ABSTRACTS OF CHEMICAL PAPERS dried first over sodium sulphate, then over sodium carbonate; the ether was evaporated and the residue distilled under a pressure of 18 mm.Between 200" and 203' C., 18 grms. of a liquid partially crystallising at about 12' C. was distilled over. A second fraction of 13 grms. distilled between 207" and 210' C.Lastly, 3.5 grms. came over between 210' and 230' C. without any definite boiling-point, and the residue amounted to 2.5 grms. The acid solution containing the glycerophosphoric acid and the choline was concentrated at a low temperature in 'uacz~o to expel most of the hydrochloric acid ; the residue was treated with 500 C.C.of water and 10 grma. of animal charcoal. The solution was neutralised with chalk, made faintly alkaline with milk of lime, and, lastly, very slightly acidified with hydrochloric acid. The filtered solution was evaporated at a temperature not exceeding 55" C. The residue was taken up with absolute alcohol, which dissolves the choline hydrochloride and the calcium chloride, leaving the calcium glycerophosphate undissolved. This latter, after drying, weighed 12 grms.The alcoholic solution was evaporated, the residue dissolved in water, and the solution treated with exactly the qnantity of sodium carbonate necessary to precipitate the calcium. The filtrate was evaporated and the choline hydrochloride extracted from the residue by absolute alcohol, the yield on evaporation being 7 grms.The products obtained by the quantitative alcoholysis of the lecithin were thus: 68 per cent. of stearo-oleic methyl esters, 24 per cent. of calcium glycerophosphate, and 14 per cent. of choline hydrochloride, whereas the theoretical values are respectively 76,26, and 17 per cent. The fatty esters consisted of methyl stearate and oleate, with possibly a little linoleate.The calcium glycero- phosphate was optically inactive, and could be split up into two fractions, one of which was crystalline and anhydrous. Alcoholysis is the best method of preparing cholesterin, which body, if present, separates in a remarkably pure crystalline state after the alcoholysis. The method has been applied to the investigation of the com- plex fats cf yolk of eggs, suprarenal capsules, and sheep's skin. J.F. B. Volumetric Method for the Determination of Phenol-p-Sulphonic Acid. C. E. Smith and H. C. Freg. ( J . Amer. Chenz. Soc., 1912, 34, 1040.)-A quantity corresponding to 0.18 to 0.2 grm. of phenol-p-sulphonic acid, is dissolved in 50 C.C. of water in a 250 C.C. stoppered flask with a long, narrow neck. To this are added 50 C.C.of a water solution containing 2-7833 grms. of potassium bromate and about 40 grms. of potassium bromide per litre, and 5 C.C. of hydrochloric acid of sp. gr. 1.13 to 1.19, the flask quickly stoppered to prevent loss of bromine, and allowed to stand at 20' to 25" C. for not less than ten or more than fifteen minutes. Potassium iodide solution, 1 grin. in 5 C.C. of water, is added, by pouring a small quantity round the stopper, which is then raised while the rest is quickly introduced.The solution is shaken and titrated with TG sodium thio- sulphate. The number of C.C. required is subtracted from 50 ; each C.C. of the remainder corresponds to 0.00435 grm. of phenol-p-sulphonic acid. The limit of error is t_ 0.5 per cent. If accurate results are required, a rough preliminary determination is necessary when the approximate quantity of phenolsulphonic acid is unknown.No indicator is needed, but starch can be used. 0. E. M.ORGANIC ANALYSIS 4G5 Parchment Paper. A. Burr, A. Wolff, and F. M. Berberich. (Zeitsch. Uutersuch. Nahr. Genussm., 1912, 24, 197-227.)-Analysss of some fifty-eight saniples of commercial parchment paper yielded the following result6 : The moisture varied from 5.49 to 13.10 per cent., but thirty-four of the samples contained less than 8 per cent.The amount of ash present in the papers ranged from 0.23 to 17-10 per cent., but in only twenty-one samples did it exceed 4 per cent. ; in a few cases lead was detected in the ash. The papers yielded from 0.05 to 31.10 per cent. of water-soluble matters, thirty-four of the samples giving more than 10 per cent.One sample of paper contained 25.78 per cent. of sugar, and only sixteen were free from this con- stituenb. There was evidence that magnesium chloride and calcium chloride were present in some of the papers. Experiments were also carried out with the object of ascertaining the suitability of parchment paper as a wrapper for butter, etc., particular attention being paid to the behaviour of those papers which contained an undue proportion of foreign substances.Parchment paper containing a large quantity of sugar favours the growth of moulds when wrapped round fresh butter, especially when the latter contains st large amount of water or butter-milk. The presence of salt (1 per cent.) in the butter hinders the growth of the moulds.When butter has to be kept in parchment-paper wrapping for some length of time, it is recommended that the paper before use be washed with hot water and then dipped in a salt solution. Although moulds do not grow well in the presence of glycerol, they are scarcely affected by the quantities of this substance which are present in parchment papers.A satisfactory paper for use as a butter wrapper would probably be one containing not more than 8 per cent. of water-soluble constituents, and yielding not more than 3 per cent. of ash. w. P. s. Hubener Bromide Method for the Estimation of Rubber. G. Hubener. (Gummi-Zeit., 1912, 26, 1284 ; through Chem. Zeiatrnlbl., 1912, II., 762.)-The author replies to criticisms, especially by Hinrichsen and Kindscher (ANALYST, 1912, 202), of his bromide method (ibid., 1909, 34, 365), and mentions a case in which a rubber, stated to consist of 90 per cent.caoutchouc and 10 per cent. sulphur, in reality contained only 65 per cent. caoutchouc, as the bromide method had shown. The substance must be sufficiently finely divided, and, in particular, not too much should be taken for bromination.Thus, 0-1 grm. of the rubber mentioned above was completely brominated by a single application of bromine water, while 0.5 grm. required four; there was no over- bromination on six applications. Commercial bromine contains sulphuric acid, so that with repeated brominations a figure may be obtained for the free sulphur in excess of the total sulphur.If the author's conditions are adhered to this is of small importance, since a similar quantity of bromine is used in the estimation of the free sulphur; and it is the difference between the figures, and not the actual figures, which is of importance. After a single bromination of 0.1 grm. substance, the vulcanisation sulphur, from the difference between free and total sulphur, was 2.06 per cent.; after four brominations, 2.61 ; and after six, 2.11. It is, therefore, not possible to assume that vulcanisation sulphur is oxidised out of rubber by bromine, and this is supported by the higher percentage of vulcanisation sulphur in Sources of error are mentioned.466 ABSTRACTS OF crmimcAL PAPERS hard rubber than. is found in soft rubber. I t is not surprising that Hinrichsen and Kindscher found a higher value for free sulphur from the sulphur in bromine water than from the sulphur dissolved in acetone.Budde (ibid., 1909, 34, 407) has already shown that acetone does not extract all the free sulphur. There is no material error due to loss of bromine from the bromide. 0. E. M. Studies on Soil Humus. S. Davitt. ( J . Ind. and Eizg.Chem., 1912,4,601-604.) -Five samples of soil were experimented with, four being low-grade soils poor in humus from Tennessee, and one rich in humus from Florida. Two methods were employed for the removal of clay-firstly, that of Mooers and Hampton, involving extraction with 1 per cent. hydrochloric acid, followed by successive volumes of 4 per cent. ammonia. The extracts are repeatedly evaporated to dryness and baked.Some months of standing with water follow, to allow the clay to settle out. The second method employed was that of mechanical separation of the clay by long standing without evaporation to dryness. Some preliminary investigations are recorded dealing with the retention of humus from water solution by ferrous iron, ferric iron, and calcium chloride. After such treatment there always remained some organic matter in solution which could be removed more or less completely by a copper salt.A starch-like substance, which gave no iodine coloration, was present to the extent of from 4 to 10 per cent. in humus from Florida; it can be hydrolised by acids and also acted upon by diastase with subsequent acid hydrolysis. Both of these processes gave reducing sugars, one of which was obtained in a cryst’alline forni, but could not be identified.The mother liquor from which this sugar was crystallised was optically inactive and easily fermentable. After fermentation it contained alcohol and acetic acid and still reduced alkaline copper solution. H. F. E. H. Study of the Acidity of Soils. A. Gregoire. (BzcZZ.SOC. Chim. Belg., 1912, 26, 386-409.)--.In a previous communication (ANALYST, 1912, 422) a method was described for the estimation of acidity based on the react’ion between potassium iodide and iodate by the use of (( Kjeldahl’s solution.” This reagent is capable of estimating the feeblest of organic acids, even those insoluble in water. At the same time it reacts also with inorganic compounds of acid function and shows marked acidity with aluminium compounds and silica.On applying the method to soils it was found that all soils, even those of alkaline reaction to litmus and containing notable proportions of calcium carbonate, showed some acidity with Kjeldahl’s reagent, and it is necessary in interpreting the results to establish some limiting standard, Un- doubtedly the main acidity of soils is due to the organic matter, and whilst the total acidity has little absolute significance, the ratio of Kjeldahl acidity to organic carbon is capable of giving very valuable information as to the normal or abnormal character of the soil.The results obtained by the author’s method as a general rule run parallel with those shown by the litmus method of Larsen and Christensen, and the Kjeldahl reagent possesses the advantage of affording direct numerical expression of the acidity or hydrogen ions.In view of the close correlation between the acidityORGANIC ANALYSIS 467 and the organic matter, the author has worked out a method for the estimation of the organic carbon by combustion of the soil previously treated with acid to decom- pose the carbcnates.The combustion tube is of quartz, 20 to 22 mm. in diameter and 700 to 800 mm. long, connected with the usual supply of oxygen at one end and charged with a layer of about 100 rnm. of copper oxide; about 5 grms. of soil are weighed out in one or two quartz boats. The arrangement for absorbing the carbon dioxide produced consists of a Pettenkofer tube, 18 to 20 min.iu diameter and 1.5 to 1.8 metre long. I t has an inclination of 120 rnm. per metre and is provided with three or four baffle cones of platinum to prevent the direct passage of the bubbles of gas. When the conibus- tion is finished the further end of the absorption tube is attached to a filter-tube con- taining a plug of abestos, similar to, but larger than, those employed for collecting the cuprous oxide in the estimation of reducing sugars.The absorption tube is then detached from the furnace and placed in a vertical position. The filtration of the barium carbonate takes place fairly rapidly and the tube is rinsed down with boiled water. The barium carbonate in the filter tube is estimated gasometrically. Scheibler's apparatus is unsuitable because it has been found that the caoutchouc The absorption liquid is a solution of barium hydroxide.bag absorbs carbon dioxide. The carbon dioxide must therefore be generated in a glass vessel and measured by displacement of air, air only coming in contact with the rubber connections. The gas evolution vessel employed is shown in the accompanying sketch (see Fig.); it is a cylinder 45 mm.in diameter and 350 mm. long, surmounted by a stopcock and bulb which is charged with acid, whilst the lower end is ground for insertion either into the neck of a flask or into the filter- tube containing the barium carbonate. This vessel is adapted to lie in a large trough of water, whilst the upper end is connected by a rubber tube with the gas-measuring apparatus. Nitric acid of 1.20 sp. gr. is employed, since with hydrochloric acid the barium chloride is only sparingly soluble. A correction must be made for the solubility of the carbon dioxide in the acid liquid. The author points out that a fixed correction, such as is usually recommended, is quite inaccurate, since the solubility of the gas depends on its partial pressure, so that the correction varies with the relative quantity of gas evolved and air present. I t is necessary, however, after evolution of the gas is complete, to close the stopcock and effect a thoroughly uniform mixture of the carbon dioxide and air remaining in the cylinder; the cock is then opened again, the levels readjusted and the reading taken. The correction for solubility is then found S x V x H by means of the formula -___-- , where S=the coeficient of solubility of pure A x 760 carbon dioxide, V = the volume of carbon dioxide read off, H = the atmospheric pres- sure reduced to 0" C., and A=the volume of the evolution vessel, up to the stopcock minus the volume of the acid. The coefficients of solubility of pure carbon dioxide in 10 C.C. of nitric acid of 1-20 sp. gr. are given as follows, in terms of gas at 0" C. and 760 mm. pressure : At 10" C., 11.48 C.C. ; 12" C., 11.28 C.C. ; 14" C.. 11.02 C.C. ; 16' C.,468 ABSTRACTS OF CHEMICAL PAPERS 10.67 C.C. ; 18" C., 10.28 C.C. ; 20" C., 9.78 C.C. ; 22" C., 9.25 C.C. ; 24" C., 8-56 C.C. I n the case of hydrochloric acid the coefficient of solubility may be taken as the same as in the case of water. J. F. B.

ISSN:0003-2654    

DOI:10.1039/AN9123700458

出版商:RSC    

年代:1912

数据来源: RSC

摘要:

468 ABSTRACTS OF CHEMICAL PAPERS INORGANIC ANALYSIS. Colour Reaction of Ammonia. P. Thomas. (Bull. SOC. Chinz., 1912, 11, 796-799.)-The blue coloration which is developed when an ammonium compound is treated with a solution of phenol and a hypochlorite is as delicate as the reaction with Nessler’s reagent, and, in the author’s view, is more specific. I t can be used in cases where Nessler’s test fails, as, for instance, in the case of liquids containing proteins, more or less cloudy.In carrying out the quantitative test a solution of rimmonium chloride containing 1 grm. in 10 litres is employed as a standard; increasing quantities of this are placed in a series of glasses, the volume being made up to 5 C.C. in each case. Then are added 1 C.C. of a 4 per cent. solution of phenol and 1 C.C.of 6‘ eau de Javel,” the commercial liquor diluted to 10 per cent. The blue coloration develops gradually after mixing and is visible at a dilution of 1 in 500,000. The reaction is applicable to the estimation of ammonia in water, but so far it has not been possible to use it in the case of organic secretions. In testing various nitrogenous substances in order to ascertain how far this reaction is peculiar to ammoniuni compounds, it is dificult to be quite sure of the absence of ammonia as a n impurity.Among the amino-acids glycocoll would appear to be the only one which shows the coloration with any intensity ; certain others develop a slight colour, but only at concentrations above 1 per cent. The amines of the fatty series are not readily obtainable perfectly free from ammonia.I t would seem that all the primary amines give the same coloration to ilr greater or less extent, methylamine and ethylamine react with great intensity. The secondary amines react feebly, but their purity is doubtful; the tertiary amines do not give the reaction. J . F. B. Acetamide shows no colour, but urea gives a pale green.Electro-analytical Estimation of Copper in Pyrites. W. D. Treadwell. (Clzem. h i t . , 1912, 36, 961.)-Copper may be deposited quantitatively by electrolysis of a solution of pyrites in aqua regia without eliminating the aqua regia. If the follow- ing directions be adhered to, the deposit will never contain more than 1 rngrm. of iron and lead, but since it invariably includes some iron, it should always be redissolved in nitric acid and redeposited.The solution of 3 to 4 grms. pyrites, which need not be filtered from gangue, is diluted to 100 to 150 c.c., and ammonia is added until a, slight permanent turbidity is produced. About 10 grms. of Rochelle salt (about 8 grms. per grm. of iron present) is next added to hold up the iron. Ammonium sulphate (5 grms.) and ammonia (20 c.c.) are added, and the solution is alectrolysed in the cold, using a gauze cathode which is rotated at a moderate speed, and preferably a cylindrical anode.The cathode must remain covered by the liquid or copper will redissolve from it under the influence of oxygen and ammonia. With a difference of potential between the terminals of 2 volts, corresponding to a current varying from about 2.7 to 0.7 amp., 0.5 grm.copper may be deposited in sixty to seventy-five minutes from a solution containing 1.5 grms. iron. If speed is no object,INORGANIC ANALYSIS 469 the use of a rotating cathode may be avoided, and the terminals of the apparatus connected to those of a single lead accumulator and left overnight. I n this case the action is started with the temperature of the electrolyte at about 40" C., and not more pyrites than corresponds to 0.3 grm.copper should be taken for the estimation. I n any case, the deposit is washed with a jet of water as the cathode is lifted out of the bath, and is redissolved in 5 C.C. of nitric acid, and the solution is boiled to expel nitrous gases and re-electrolysed, preferably with the use of a rapidly rotating cathode, and the current from two Edison accumulators short circuited through the bath (about 2.6 volts). This second electrolysis occupies only ten to fifteen minutes.The first one may be accelerated by the use of hydrazine sulphate or sodium bisulphite to reduce the iron to the ferrous state, instead of leaving this work to the current, but this is not permissible if the pyrites contains arsenic, for these reagents reduce arsenic to the arsenious condition, with the result that arsenic is deposited on the cathode with the copper.G. C. J. Reaction of Gold Salts with m-Phenylenediamine. J. A. Siemssen. (Chem. Zeit., 1912, 36, 934.)-A solution of m-phenylenediamine (5 : 1,000) is a sensitive reagent for gold salts, and will give au immediate violet coloration with a 0.005 per cent.solution of gold chloride, With stronger solutions of the gold salt (0.5 per cent,) the reagent gives colorations ranging from yellow to dark brown. The 9%-phenylenediamine solution must be decolorised, if necessary, by boiling with freshly ignited animal charcoal. C. A. M. Separation of Iron from Titanium. F. Bourion.(Alan. Chim. anal., 1912, 17, 281-284.)-The extreme error of the method, which has been described before (ANALYST, 1912, 323), is k 2 mgrms. when operating on 0.5 grm. or less of the mixed oxides. G. C. J. Quantitative Separation of Lanthanum from Yttrium, C. James and T. 0, Smith. (Chem. News, 1912, 106, 73-74.)-The following method was found to give a more perfect separation than the potassium sulphate method.It depends on the insolubility of lanthanum magnesium nitrate in concentrated nitric acid saturated with bismuth magnesium nitrate. Yttrium forms no double nitrate with magnesium. The solution containing lanthanum and yttrium as nitrates is evaporated to dryness, and the residue is treated with 25 C.C. of concentrated nitric acid saturated with bismuth magnesium nitrate.Solid bismuth magnesium nitrate (10 grms.) and 1 grm. of magnesium nitrate are added, and the mixture warmed and stirred, and then allowed to stand for twenty-four hours. The crystalline deposit is filtered off on a Gooch crucible, and washed with nitric acid saturated with bismuth magnesium nitrate. The filtrates and washing are evaporated t o dryness, the residue is treated with 200 C.C.of cold water, and bismuth is precipitated with hydrogen sulphide. The bismuth sulphide is filtered off and washed with cold water, and the filtrate is boiled to expel hydrogen sulphide, cooled, treated with ammonium chloride, and nearly neutralised with ammonia. Yttrium is then precipitated by means of oxalic acid, and the oxalate ignited to the oxide and weighed.The Ianthanum magnesium470 ABSTRACTS OF CHEMICAL PAPERS nitrate and bismuth magnesium nitrate in the Gooch crucible are washed into a beaker, bismuth is precipitated as sulphide, and in the filtrate from the bismuth sulphide lanthanum is precipitated in a nianner exactly similar to that followed in the case of yttrium. With 0.2 grm. of lanthana and 0.2 grm.of yttria, present, the amount of each earth may be determined with an error which does not exceed ?I: 4 mgrms. I t is pointed out that the error would probably be greater if the method were applied to the separation of lanthanum from holmium and dysprosium, since these elements have a tendency-slight though it may be-to form double nitrates with magnesium. On the other hand, the method might be expected to give a nearly perfect separation of lanthanum from those members of the yttrium group, the nitrates of which are more soluble than that of yttrium itself.In the author's hands the potassium sulphate method underestimates yttrium by more than 10 per cent., and no satisfactory results were obtained by substituting sodium sulphate for potassium sulphate, nor by methods depending on the different solubilities of the formates and cacodylates of lanthanum and yttrium.G. C. J. Determination of Lithium. L. R. Milford. (J. h z d . and Eng. Chem., 1912, 4, 595-597.)-Of mineral waters containing much sodium and potassium relatively to lithium, 250 C.C. are evaporated to dryness in a large platinum dish, with occasional addition of a few drops of hydrochloric acid.The residue is heated to 120° C. for half an hour to render silica insoluble, and is then moistened with hydrochloric acid and rubbed up with 25 C.C. of 95 per cent. alcohol. The alcoholic extract is filtered, and the insoluble matter washed with 95 per cent. alcohol so long as lithium can be detected spectroscopically. The alcoholic filtrate and washings are evaporated to dryness, a little hydrochloric acid being added towards the end, and the residue is extracted and the extract filtered as before, but using absolute alcohol in place of weaker spirit.The alcoholic filtrate is evaporated to dryness, and the residue taken up in a little dilute hydrochloric acid. Magnesia is precipitated by addition of au excess of calcium hydroxide, and the solution is filtered, and most of the lime precipitated by addition of ammonia and ammonium oxalate.After standing over- night, the calcium oxalate is filtered off' and washed with at least 100 C.C. of water, or until lithium can no longer be detected. The filtrate and washings are evaporated to dryness, ammonium salts expelled at a low temperature, and the residue taken up once more in a little hydrochloric acid.Ammonia and ammonium oxalate are added again, any precipitate which separates at once or on concentrating is filtered off, and the filtrate is evaporated to dryness, and ammoniurn salts expelled by heating in platinum just short of redness. The residue is taken up in water, filtered and washed, using as little mash-water as possible, and is then evaporated with hydro- chloric acid and chlorine-water to decompose any bromide or iodide.The ignited residue is taken up with a little water, and the solution, acidified by a, few drops of hydrochloric acid, is transferred to a large platinum dish. About 30 C.C. of arnyl alcohol are added and the water boiled oft', with constant stirring to prevent bumping. A drop of dilute hydrochloric acid is added to reconvert traces of lithium hydrate to chloride, and the solution is concentrated to about 15 C.C.on the steam-bath, and then filtered into a platinum dish and evaporated to dryness. This trssttment withINORGANIC ANALYSIS 471 am yl alcohol separates most of the sodium and potassium chloride which escape separation by means of alcohol in the earlier stages of the process.The residue of lithium chloride is treated with water and a few drops of sulphuric acid and evapor- ated to dryness, the excess of acid is expelled by heating to dull redness, and the residue again taken up in water. Ammonia is added to precipitate the last trace of magnesia, which is filtered off and washed with boiling water. The filtrate and washings are evaporated to dryness, freed from ammonium salts, and the treatment with ammonia repeated until no further precipitate of magnesia is formed.The lithium is finally weighed as sulphate, and a deduction of 1.7 mgrms. is made to correct for the solubility of sodium and potassium chlorides in amyl alcohol. G. C. J. Gravimetric Estimation of Magnesium. L. Karaoglanow.(Jahrbwh d. unio. XoJia, 1910-1911, 1-57 ; through Chenc. Zentralb., 1912, I I . , 548-549.) - Magnesium ammonium phosphate, precipitated from solutions of magnesium chloride or nitrate, should be washed with ammonia containing amtnonium salts, but pre- cipitates obtained from the sulphate are best washed with 2.5 per cent. ammonia. The method of Neubauer always gives higher results than the method of Gibbs or that of Schmitz, and the results obtained by the latter methods agree closely with those yielded by the oxide and sulphate methods, which the author has slightly modified with a view to making them sufficiently accurate to serve as control methods in his experiments on the phosphate method.The high results yielded by Neubauer’s method are not due to the formation of (NH,),Mg(PO,),, as Neubauer, and also Gooch and Austin, have assumed, but are probably due to the power of adsorption possessed by the amorphous or granular magnesium ammonium phosphate. Pellet’s method is useless for quantitative purposes, since no definite magnesium sulphopyrophosphate is obtained, but only an equilibrium between magnesium pyrophosphate and sulphuric acid.G. C. J. Volumetric Estimation of Manganese. L. Karaoglanow. (Jahrb. der Unav. Sofia, 1910-1911, 1-33 ; through Chem. Zentralbl., 1912, II., 548,) - Some of the disadvantages of Volhard’s method disappear when it is applied to solutions of manganous nitrate instead of to solutions of the sulphate. For example, the titration can be carried out in presence of ferric nitrate and aluminium nitrate, whereas the corresponding sulphates hinder the action of permanganate on manganous sulphate.Moreover, manganous nitrate can be titrated in nitric acid solution, whereas in sulphuric acid solution manganion is not oxidised by per- manganate. The presence of the nitrates of barium, zinc, potassium, and silver, further the reaction between manganous nitrate and permanganate.Ferric nitrate and aluminium nitrate in high concentration limit it, their action depending on their tendency to hydrolytic dissociation in aqueous solution, the nitric acid thus set free being the agent which interferes with the oxidation. The method always gives results somewhat below the truth, the most accurate results being those obtained in presence of some ferric nitrate.The most convenient form of the method, however, is that in which silver nitrate is added to the solution to be titrated, the results under472 ABSTRACTS OF CHEMICAL PAPERS such circumstances being ‘( sufficiently exact.” Silver nitrate reacts with manganous acid to form silver manganite, the amount of the latter formed depending on the relative concentrations of silver nitrate, manganous nitrate, and manganous acid.I n practice, the precipitate consists mainly of manganous acid, the greater part of the silver nitrate remaining unchanged in the solution. If other nitrates are present, even less silver manganite is formed, the other metals replacing the silver of silver rnanganite. These other metallic ions exercise a similar influence on the divalent manganese of manganous manganite.This is the explanation of the favourable influence of metallic salts on the reaction between perman- ganate and rnangarous nitrate. Equivalent quantities of different metallic nitrates displace different quantities of silver or manganese from their combination with manganous acid ; the order is ferric, silver, zinc, aluminium, barium, and potassium nitrate.The same order applies to the accuracy of the results when manganese nitrate is titrated with permanganate, the most exact results being those obtained in presence of a reasonable amount of ferric nitrate. The variation in the results cannot be ascribed to disturbed equilibrium bet ween manganous manganite and metallic nitrate, but depends on the fact that the formation of manganous manganite cannot wholly be prevented even if the titration be conducted in presence of a great excess of another salt.Once manganous manganite is formed, however, it is with diffi- culty either oxidised by permanganate or substituted by another metal, since the system is heterogeneous. The author’s work proves the untrustworthiness of Rossler’s method for the volumetric estimation of manganese, and throws doubt on Rose’s method for the preparation of silver manganite, which afforded the basis of Rossler’s method.G. C. J. Absorption of Ultra-violet Rays in Ozone, and its Application to the Estimation of Ozone in Small Concentrations. F. Krueger and M. Moeiler. (Physikal. Zeitsch., 1912, 13, 729 ; through Chenz. Xentralbl., 1912, II., 748.)-The rapid absorption in the region of wave-lengths from 200 to 300 pp may be used for the estimation of ozone if the coefficients of absorption for the several wave-lengths are accurately known.The authors find that the maximum absorption has the position assigned to it by E. Meyer (Annaleiz der Physik., 1903, 12, 849), but that his coefficients of absorption require correction.The light from a quartz mercury vapour lamp was passed through a quartz prism, a slit, the absorption-tube, and a photo-electric potassium cell. The current, measured by means of a quadrant electrometer, is a measure of the intensity of the light. Comparative tests with known concentrations of ozone gave satisfactory results with the new data. The optical method is more sensitive than the chemical, and can be carried out on lower concentrations.0. E. U. Estimation of Inorganic Phosphorus in Plant Substances. R. C. Collison. (J. Ind. and Eng. Chem., 1912, 4, 606-609.)-Dilute acid extracts of plant substances contain proteins, carbohydrates, and, in the case of cereals, salts of phytic acid, besides inorganic salts. All these substances, especially the salts of phytic acid, inhibit the formation of ammonium phosphomolybdate.The author previously (Ohio Agr. Exp.INORGANIC ANALYSIS 473 Sta. BuZZ., No. 215) recommended a preliminary extraction with 0.2 per cent. hydro- chloric acid, followed by precipitation with magnesia mixture. The dried precipitate was then thoroughly extracted with a measured volume of acid alcohol, the mixture filtered, and phosphorus determined in an aliquot portion of the filtrate, thus avoiding the precipitation of phosphorus in presence of proteins and salts of phytic acid.The author has since found that cold alcohol (94 per cent.) containing hydrochloric or nitric acid (0.2 per cent.) dissolves the common phosphates which are insoluble in neutral or slightly alkaline alcohol.Proteins in general, nucleinic acid from yeast, carbohydrates and salts of phytic acid, are mostly insoluble. He therefore recom- mends such an acid alcohol extraction of the material followed by filtration, thus leaving behind the undissolved organic phosphorous in the residue. The method was fully investigated on soya beans, rice polish (on account of its high content of phytin), and maize germ meal.Known amounts of inorganic phosphorus were added to these materials and recovered with accuracy. Ten grms. of the finely- ground material is placed in a 400 C.C. flask and covered with 300 C.C. of the acid alcohol solution referred to, the whole being shaken every five minutes for three hours. After filtration an aliquot portion is made just alkaline with ammonia, and then allowed to stand eight to twelve hours.The precipitate is filtered of& washed with 94 per cent. alcohol made faintly ammoniacal, and then dried, after which it is dissolved in 100 C.C. of 0.5 per cent. nitric acid. The material is again filtered and precipitated with acid molybdate solution. A further advantage of the proposed method is that alcohol extraction tends to prevent enzymic and bacterial decomposition of organic phosphorus compounds, evidence being given that in many cases variations in results have been duo to the splitting off of inorganic phosphorus from organic compounds. Analyses of some thirteen substances are recorded by the acid water and acid alcohol methods, with and without the addition of known amounts of inorganic phosphorus, in all cases the results agreeing with the theoretical figures when the latter method is used, and in five cases only when the acid water method was adopted, these five being materials which do not give much orgsnic matter on extraction.H. F. E. EL. New Compensation Method for the Comparison of Quantities of Radium, and some Applications of this Method.E. Rutherford and G. Chadwick. (Le Radium, 1912, 9, 195 ; through Claem. Zentralbl., 1912, II., 752.)-A preparation of unknown radium content is best compared with a standard by means of the y-radiation. I t is a necessary condition that the preparation shall contain no meso- thorium or radiothorium, as both give off y-rays nearly equal in effect to those of radium. The intensities should not be greatly different, as with ratios of 10 to 1, €or example, it is difficult to be certain that there is complete saturation of the ionisation current in the electroscope. To avoid this difficulty, the authors have evolved a compensation method, in which the y-rays from the radium preparation produce a saturation current, which is compensated in an ionisation vessel by an opposed constant ionisation current from a preparation of uranium oxide.Exact compensation is effected, with the help of a Dolezalek electrometer, by adjusting the distance from the ionisation vessel of the radium preparations, the intensity of which474 ABSTItA4CTS OF CHEMICAL PAPERS is then proportional to the square of this distance. Corrections for the absorption in air, and, if necessary, in glass, are applied in accurate determinations.Further corrections, for which the original should be consulted, are necessary for the estima- tion of radium emanations. The y-activity of a considerable quantity of radium emanation gave by this method an exponential decrease, with a limit of 3,854 days ; a tube filled with radium emanation reaches its maximum in 255 minutes.The emission of y-rays was not affected by bringing the emanation into a powerful magnetic field. 0. E. M. Continuous Fractional Distillation of Water. W. R. Bousfield. (J. Chenz. Soc., 1912, 101, 1443-1453.) - Water having a conductivity represented by Kls = 1 x 10-6 is taken as having unit conductivity. I n a previous paper (J. Chem. Soc., 1905, 87, 740) an apparatus yielding water of this order of purity by continuous fractional distillation of tap water was dealt with by the author, and he now describes, with drawings and full details (for which reference must be made to the original), two forms of still more readily managed, and of a simpler type.The first of these-intended for everyday purposes-yields about 30 litres of water per twenty- four hours, two-thirds of which has a conductivity of about 0.8, the rest being of ordinary character.If a strong solution of alkaline potassium permanganate is supplied with the feed-water at the rate of about 10 drops a minute, water of a slightly lower conductivity may be continuously produced. The other apparatus is suited for the continuous redistillation of water under diminished pressure, and by its use water having a conductivity of only 0.5 may be continuously produced by the redistillation of the ordinary product of the first still.Criticising Hartley, Campbell, and Poole ( J . Chem. Xoc., 1908, 93,428), it is shown by several experiments that marked differences characterise the conductivities of the condensation products when waters containing traces of ammonia and acetic acid respectively are distilled and allowed to condense on (1) warm and (2) cold surfaces.In the distillation of ordinary water the ‘‘ hot-surface ” product is the purer when employing the first of the stills figured in the paper ; while in the second, as in the still orginally described (Zoc. cit.), the cold-surface product is the purer, and is probably of a higher degree of purity than any hitherto produced on a large scale by any previous arrangement of still.The purest product is obtained from the hot surface, when the rate of distillation is so arranged that the proportions of distillate collected from the hot and cold surfaces are about 2 to 1. Working so as to obtain this ratio, with a total output of 18 litres per hour, with 3 inches gas pressure, the following conductivities were obtained from the first still : %3* -- Hot-Surface Product.Cold-Surface Product. 1. From tap water only ... ... 0.90 10.0 permanganate . . . .. . ... 1.20 2.0 3. With 10 drops per minute ... 0.75 2.8 2. With a large addition of alkaline The paper closes with a description and illustration of the second, or “three- bottle,” still in series, where an electric heating source is employed in the firstINORGANIC ANALYSIS 475 bottle, the surface ” water going into the third.hot-surface ” product collecting in the second bottle, and the ‘( cold- H. F. E. H. H. C. McNeil. (Chem. Eng., 1912, 16, 38-40.)-This method has been made use of for a variety Calcium Carbide Method for Estimation of Moisture.of analyses by different observers (cf. P. V. DuprB, ANALYST, 1909, 30, 266; 1906, 31, 213; R. A. Cripps and J. A. Brown, 1909, 34, 519; I. Masson, 1911, 36, 112). The author’s apparatus for measuring 3 w ~ r 5 1 ~ 1 p m ~ _ - the acetylene given off by reaction with the moisture-containing sub- stance, shown in the figure, has been used for the examination of soaps, \ paints, leather powder, and infants’ foods.The reaction flask, A, has a, capacity of 25 c.c., and into it a weighed amount of the sample in powder form is introduced. Barium sulphate, silica, or similar material is used to mix with the substance, if necessary, so that the carbide will readily mix with i t ; or the sample may be dissolved or suspended in a liquid, such as toluene, amyl alcohol, or even kerosene and heavy mineral oils.The tube B is charged by filling the side projection with carbide ground to a fine powder, a cotton- wool plug pushed down to the con- striction, and a little more carbide, covered with wool, placed alternately until the tube is loosely packed, to prevent loss of moisture. The stop- cock, F, is opened to the air by pulling it partly out, after connecting A with B, and B with C by means of tubing, etc., as shown.The flask A and tube B are surrounded with the vessel G, and water is run through C and G till the apparatus is at the . . . . n - temperature of the water, and when the burette is reading zero by adjustment with E’ the tap F is turned so that B and C are in communication. A little carbide is then476 ABSTRACTS OF CHEMICAL PAPERS tipped into A and the rate of reaction carefully controlled.The flask is thoroughly shaken, and the mixture heated for about fifteen minutes, by surrounding the vessel with a bath of boiling water. The apparatus is then reduced to the initial temper- ature, and the measurements made. The tube H is an auxiliary container for use in the case of substances containing much moisture, or of such a nature that a fair sample in small amounts cannot be obtained.I n such cases F is turned to connect C, H, and A , and the resultant gas is lead from H into C and cooled, measured, and passed out in portions. Mercury is used in the apparatus, or strong brine saturated with acetylene, and coloured with alkali and phenolphthalein.The apparatus should be standardised, so that the amount of gas given off from carbide by a definite amount of water is known. Practically, 1 grm. of water yields about 582 C.C. Paints, pastes, and soaps, should be mixed with freshly ignited barium sulphate in sufficient amount to overcome pastiness, and then sand is added to make the mass granular. Alcohol may be used in the case of soaps, instead of the dry method just described, provided that it is first treated with calcium carbide and saturated with acetylene.The infants’ foods examined reacted only slowly, the reaction being in some cases incomplete after one hour at 100” C. A. R. T. Assay of Sodium Peroxide for Bleaching Purposes. W. Herbig. (Fiirber Zeit., 1912, 23, 193-196 ; through Chem.Zeiztyalbl., 1912, II., 636-637.)-1n the author’s experience the gasometric method for the assay of sodium peroxide often gives too high results, values sometimes equivalent to 114 per cent. of sodium peroxide, which can only be explained by the presence of some higher oxide--e.g., the tri- or tetroxide of sodium. Such higher oxides are of no interest to the bleacher. With the permanganate titration method satisfactory results are obtained by the following procedure : A mixture of 200 C.C.of water and 200 C.C. of dilute sulphuric acid (1 : 5 ) is cooled to 0” C., by the addition of some clean ice, the permanganate- consumption of which has been previously determined. The height of the liquid in the beaker should be 10 or 12 cm. Then a weighing tube containing 0.2 to 0.3 grm.of sodium peroxide is quickly dropped in a, horizontal position to the bottom of the beaker. The air in the weighing tube only allows the acid to come gradually in contact with the peroxide, so that decomposition is slow. If the acid attacks the peroxide all at once the results show considerable variations. The iodometric method may be carried out in a similar manner.The peroxide enclosed in a weighing tube is introduced into a 10 per cent. solution of potassium iodide acidified with hydro- chloric acid, and the flask is kept stoppered for forty-five minutes ; the liquid is then diluted largely, and the iodine titrated with thiosulphate. The results are concordant if the iodide solution be sufficiently strong during the reaction, but it must be sufficiently diluted before the titration; the acid must be present in excess, and, above all, the thiosulphate solution must only be added drop by drop.Certain samples of sodium peroxide contain greyish black grains consisting apparently of sodium ferrate; such impurities are liable to be very injurious to the cloth in the bleaching process. J. F. B.INORGANIC ANALYSIS 477 Volumetric Determination of Tin.W. W. Patrick and G. C. Wilsnack. (J. Ind. and Eng. Chem., 1912, 4, 597-599.)-1f the alloy does not contain more than 6 per cent. of lead or copper, an amount corresponding to 0.5 grm. or less of tin is taken for analysis, and if the sample contains less than 0.15 grm. of antimony, some powdered antimony is weighed out with it. Solution is effected in a 500 C.C.Erlenmeyer flask by heating with 10 C.C. of sulphuric acid. To the cooled solution 10 C.C. of water is added, and this is followed by 60 C.C. of hydrochloric acid, and a further 40 C.C. of water. The flask is fitted with a four-hole rubber stopper. Through one hole passes a tube for the introduction of carbon dioxide to the bottom of the flask. Another hole carries a short bend which is connected by flexible tubing to a 100 C.C.pipette which dips into water, and serves to prevent air being sucked into the apparatus if the flow of carbon dioxide is not quick enough to prevent the formation of a partial vacuum when the contents of the flask are cooled. A third hole carries a glass rod of such diameter that it can easily be moved up and down.I n its lowest position it should nearly touch the bottom of the flask, and at its lower end it ha3 sealed to it a, platinum hook to which is attached a spiral of very pure iron made from a 4-inch by &inch strip of +-inch plate. The fourth hole carries a piece of &-inch tubing, drawn out to a jet below and with a lateral hole blown on it just above the jet.This tube serves for the introduction of the iodine solution used for titrating the tin, and also for the introduction of water to wash the iron coil when this is raised out of the liquid. With this latter object the jet is bent at a slight angle from the vertical. The lateral hole allows carbon dioxide to escape without impeding the even delivery of iodine solution drop by drop. This stopper being fitted to the flask, and the jet tube being suitably plugged, the air in the flask is displaced by carbon dioxide, and the contents of the flask are maintained in gentle ebullition for twenty- five minutes, and then cooled in running water, the current of carbon dioxide being continued all the time.The iron wire is raised out of the liquid and washed free from tin solution by means of freshly boiled water admitted through the jet tube.The tin is then titrated with iodine and starch, after raising the iron coil to such a position that iodine falling from the jet cannot come in contact with it. Alloys containing more than 5 per cent. of copper or lead are decomposed by covering with 10 C.C. of concentrated nitric acid, followed by evaporation to dryness. The residue is baked strongly for fifteen minutes, and, when cool again, is rubbed up with 20 C.C.of dilute (1 : 1) nitric acid. The insoluble matter is filtered off, washed with hot water, and then transferred with the filter-paper to a 500 C.C. Erlenmeyer flask, in which it is digested, at first at a gentle heat, with 20 C.C. of sulphuric acid and 2 grm. of potassium sulphate. Before the liquid loses its black colour, it is allowed to cool, and any carbon on the sides of the flask washed down with water, aided, if necessary, by a ‘‘policeman.” The digestion is then continued until the solution is colourless. To the cooled solution, 50 C.C.of water and 45 C.C. of hydrochloric acid are added, and the reduction and titration of the tin completed in the manner already described.The maximum error of the method is 1 in 400 if sufficient of the alloy is taken to give a large reading on the iodine burette. G. C. J. The iodine solution is standardised on the purest tin obtainable.478 ABSTRACTS OF CHEMICAL PAPERS Analysis of the Waters of the Thermal Springs of Bath. I. Masson and W. Ramsay. ( J . Chcm. Xoc., 1912,101, 1370-1376.)-The King's spring, the largest of the three main springs, delivers half a million gallons in twenty-four hours at a, temperature of 50" C.Potash drinking glasses, after prolonged use, turn yellow owing to the niton or radium emanation contained in the water having liberated potassium in an atomic state of subdivision. Soda glass, similarly exposed, turns pale violet.The water has a density of 1-0175 at 4 O C., and a freezing-point of - 0-07" C., and gas escapes at the rate of 4,927 litres in twenty-four hours. Oxygen, hydrogen, and methane were absent from this gas, and 168 C.C. of residual inactive gases freed from CO, by potash and from nitrogen by passing through red-hot tubes charged with magnesium lime, were fractionally condensed in charcoal cooled with liquid air.Helium and krypton were absent, and calculation showed the presence of 88.7 C.C. of argon and 7-9 C.C. neon. Portion 2 measured 61 c.c., weighed 1.3509 grm. per litre, and consisted of 31.1 C.C. of argon and 29.9 C.C. neon, Helium lines were absent. Portion 3 was uncondensable by charcoal, the weight of a litre was 0.2681 grm., and the fraction measured 5.6 C.C. ; 4.9 C.C. of helium and 0.7 C.C. of neon were calculated to be present. Adding these three portions together, the total gas contained per litre is CO,, 36 C.C. ; nitrogen, 954-1 C.C. ; argon, 7.263 C.C. ; neon, 2-334 C.C. ; and helium, 0.297 C.C. Bath gas, therefore, contains 0.779 times as much argon, 188.1 times as much neon, and 72.8 times as much helium as atmospheric air. In the total of 5,363 litres of gas escaping daily from the three springs, there are 39 litres of argon, 12.5 litres of neon, and 1.6 litres of helium. Niton or radium emanation is also present in too small quantity for chemical estimation, but was measured by comparing the rate of dischrtrge of an electroscope filled with Bath gas, with the effect produced by the niton accumulated during a definite time from a standard solution of radium bromide containing Tu$uu mgrm. of metallic radium. The niton in a million litres of gas from the King's spring was thus found to be in equilibrium with 33.65 mgrms. of radium. The residue left on evaporating the water had the following composition in mgrrns. per litre : Li, 0.16 ; Na, 181.1 ; K, 16.7 ; Mg, 4.1 ; Ca, 335.7 ; Sr, 3.2 ; Fe, 40.2 ; Al, 9.7; As, trace ; C1, 154.8 ; Br, 4.4 ; SO4, 1054 ; CO,, 15.8 ; Si0,-. Total, 1811*0. The rare eart.hs were absent. Radium, as metal, amounted to 0.1387 rngrms. in a million litres, the small quantity being due to the high percentage of sulphate. Some deposit on the old Roman lead pipes still at the spring consisted mainly of calcium sulphates. The radium in it was determined, since in 1,760 years half of that originally present would have changed into niton and its products. One part of radium in 10 million parts by weight of the deposit were found. Radium was not detectable in the modern deposit. Portion 1 measured 96 c.c., and weighed 1.706 grm. per litre. H. F. E. H.

ISSN:0003-2654    

DOI:10.1039/AN9123700468

出版商:RSC    

年代:1912

数据来源: RSC

摘要:

478 ABSTRACTS OF CHEMICAL PAPERS APPARATUS, ETC. Application of Light Energy to the Study of Certain Problems in Analytical Chemistry. M. Landau. (Compt. rend., 1912, 155, 403-406.)-The author has studied the action of ultra-violet rays on certain hydrocarbons and carbon monoxide. This action is of two kinds : I t causes the polymerisation of unsaturatedAPPARATUS, ETC. 479 gaseous hydrocarbons into liquid and solid bodies, whilst in presence of excess of oxygen it brings about photocombustion of hydrocarbon and carbon monoxide gases. The polymerising action is very slow, even when a powerful quartz mercury laimp of 500 volts is used at a distance of 4 cat.I n the case of ethylene, the shrinkage of a volume of the gas amounted to 71 per cent. after nineteen hours, whilst a much longer exposure was required to produce complete condensation. I n the case of acetylene the action was still slower.The photocombustion was studied in the case of ethane mixed with an excess of oxygen; combustion was complete after sixteen hours’ exposure. The combustion of methane was more difficult, and incomplete in the time devoted to its study. That of carbon monoxide amounted to 72 per cent.i n fifteen and a half hours, and was complete after longer exposure. In the com- bustion of hydrocarbons, intermediate products, including carbon monoxide, were formed. The combustions were carried out at a temperature of 80” C. The above reactions were applied to the analysis of a mixture of ethane, ethylene, and hydrogen. Such a mixture cannot be resolved by explosive combustion, because ethylene and hydrogen together are equivalent to ethane; but by a very prolonged exposure to the ultra-violet rays in absence of oxygen the ethylene may be condensed by photo-polymerisation and the contraction measured; oxygen is then added in excess, and the residue submitted to photocombustion.The spectra of the gaseous hydrocarbons show a strong absorption of ultra-violet rays whereas those of carbon monoxide and dioxide do not. J.F. B. The ‘‘ Sapometer.” C. Huggenberg and H. Stadlinger. (Chem. Zeit., 1912, 36, 938.)-The special form of burette here illustrated is recommended for use in soap aualysis. A weighed quantity (about 10 grms.) of the soap is dissolved in warin water, the solution poured into the sapometer,” which has previously been charged with 30 C.C.of sulphuric acid, and warm water added to bring the total contents to about 97 to 100 on the bottom scale. After the mixture is cold the fatty acids are extracted by shaking with ether or a mixture of ether and petroleum spirit, which is added until the contents reach a mark on the top scale, Any aliquot part of the upper ethereal solution may then be drawn off through the tap at the side and evaporated, while the lower layer is used for other estimations.The apparatus may be obtained from Altmann, Luisenstrasse, 47, Berlin. c. A. If. Apparatus for Automatically Decanting and Washing Precipitates. E. Sinkinson. (Chem. News, 1912, 106, 49-50.)- The decanting and washing parts of the apparatus are separate, the former consisting of supports for the funnel and the beaker480 ABSTRACTS OF CHEMICAL PAPERS containing the precipitate and liquid, and the latter of a rotating jet worked electrically. The funnel containing the filter-paper is supported in a ring at one end of a balance-arm, and is counterpoised by a sliding weight on the other arm. By moving the weight the amount of liquid run into the filter can be regulated. When sufficient liquid has run into the filter, the funnel drops and is arrested by a fixed support, which carries four mercury cups serving to make and break electrical contact, and so controlling the motors regulating the supply of liquid to the filter.The beaker containing the liquid is supported on a sloping table, the slope being controlled by a motor.Thus, when the funnel drops, the motor is reversed and the liquid ceases to pass into the filter. When decantation is complete, and the precipitate has been transferred to the filter, the washing attachment is brought into use, the jet of wash- water being rotated by means of a worm-gearing electrically actuated. The operations of decantation and washing are carried out automatically, and the apparatus requires no attention except when the washing attachment is to be connected.The original paper is illustrated by four diagrams of the apparatus. A. R. T. the filter-flask is joined c E to Valve for Filter Pumps. H. B. Hutchinson. (Chein. News, 1912, 106, 99.)-This valve, which is of special use when the water supply is subject to much variation, consists of a stout glass-tube, A , 9 inch to 2 inch diameter fitted with two single-bored rubber corks, B, and Bz, between which is placed a solid rubber bung, C, with its wider end downwards, and fitting loosely into the tube.A glass tube, D, with an oblique lower end, is pushed through R,, until it is about 1 to 2 mm. from the upper surface of the bung, C, and a second tube, E, is brought sufficiently far through B, to enable it to act as a support without bulging the upper surface of the cork.The valve may be used alone or attached to a smell filter flask aB shown. The latter way keeps the corks moist, which is an advantage, but when the valve is intended only as an air valve, it is best moistened with dilute glycerol. The tube D is then attached to the pump, and E on the side-tube of the filtering or vacuum distillation apparatus.Messrs. Gallenkamp supply the valve. H. F. E. H. Apparatus for Automatic Analysis of Liquids. (Chem. Zeit., 1912, 36, 962.) -The apparatus figured serves for the automatic and periodical estimation of any constituent of a liquid which yields a gas on admixture with an appropriate liquid reagent-for example, for the estimation of ammonia in aqueous solution by the hypobromite reaction.The reagent is stored in the vessel o whilst the liquid to be controlled flows steadily through the cock a into b, continually overflowing through c. The whole apparatus is operated by the syphon tank v, and theAPPARATUS, ETC. 481 periodicity of its operation is controlled by the cock 26, connected to a water-supply system.As the tank and tube zu fill, the air-pressure forces the liquid in the bulb t into s, thus sealing the end of the tube T , which is the sole route by which gas can escape from the gas-bell g. With increasing head of water iu zu the (arnmoniacal) liquid in the measuring tube Z is forced into the reaction chamber k, and at the same time a measured portion of the reagent (hypobromite solution) is forced from p into k.The reaction chamber k is provided with means to ensure intimate mixture of the reacting liquids and with an automatic overflow. The gas generated in Tc passes through T to the gas-bell g, which rises, and in rising lowers a pencil which traces a continuous line on the clockwork drum d.Finally, the syphon y operates, the tank empties itself, the level of the liquid in s falls sufficiently to allow the gas in the bell to escape through T , the reagent measure p refills immediately, and the measure I fills more slowly with the liquid to be tested. The cycle of operations is then repeated. The point of minimum depression of the pencil are obviously a measure of the amount of ammonia (or other constituent to be estimated) in the liquid, and once the instrument has been calibrated the drum can be supplied with paper ruled to give absolute readings.The makers of the instru- ment, J. v. Geldern and Co., Diisseldorf, supply with it a self-acting compensator for variations in temperature and barometric pressure. This attachment is not shown in the figure.G. C. J. Constant Flow Aspirator. J. F. Hoffmann. (Zeitsch. angezu. Clzenz., 1912, 25, 1723-1724.)--A Mariotte aspirator, when operated at a low speed for long periods, often works irregularly on account of the accumulation of gas bubbles in constricted portions of the apparatus. The apparatus here figured overcomes this difficulty. The horizontal limb of the T-tube, which is conveniently constructed from a broken burette, passes through a rubber stopper in the tubulus of the aspirator (not shown in the illustration).Through a rubber collar, a capillary of suitable dimensions is pushed up into the vertical limb of the T-tube, and the advantage of having the latter constructed from a graduated tube lies in the fact that the speed of flow may be regulated by raising or lowering the capillary, and the graduated tube facilitates fine regula-482 REVIEWS tion. Before setting the apparatus in operation, the bulb which closes the top of the burette is partly or wholly filled with water by suction, and its limb closed by means of a piece of rubber tube and a glass plug. Any bubbles of gas which may escape from the water accumulate in the bulb, and do not interfere with the regular flow of water. G. C. J.

ISSN:0003-2654    

DOI:10.1039/AN9123700478

出版商:RSC    

年代:1912

数据来源: RSC

摘要:

482 REVIEWS REVIEWS. METHODS OF ORGANIC ANALYSIS. By H. C. SHERMAN. Second edition. New Yo&. The descriptions of the methods in this book were written primarily for the use of third-year students, and, consequently, the technical analyst will find compara- tively little that will assist him. I n some respects the work is quite up to date. For instance, the methods of glycerin analysis are those of the International Committees, but in others the methods given are nearly obsolete ; and as an instance butter inay be cited, the Reichert-Meissl method being described jn full, while probably the modification of Polenske is now universally employed.The best feature of the book is the full and clear descriptions of the methods, which are followed by explanatory notes, and the list of references for the student who wishes to follow up the subject.The work appears admirably designed for the purpose for which it was written. 1912. The Macmillan Go. Pp. xvi + 407. Price 10s. 6d. neb. H. DROOP RICHMOND. WATER ANALYSIS FOR SANITARY AND TECHNICAL PURPOSES. By HERBERT B. I n his preface the author states that he 6 L has endeavoured to give a concise and accurate description of the methods adopted for the analysis of waters for sanitary and technical purposes, with the hope that the information may be of use to Public Analysts, Medical Officers of Health, and students who are interested in this branch of analytical work.” The volume contains 136 pages, of which twenty-eight are devoted to the organic carbon and nitrogen process of Frankland.Neither the arrangement nor treatment of the subject-matter is original, and although most of the ordinary processes are described, the details and hints given are, in several cases, hardly sufficient to enable those unacquainted with water analysis to obtain the most accurate results. The illustrations are but few, and more than half of them poor in quality. The ‘‘ apparatus for estimating free and saline ammonia,” figured on p.10, probably com- pares unfavourably with that to be found in most water-analysis laboratories, and the illustration of the combustion apparatus, given on p. 30, is faulty at one point, and the simple gas-measuring tube indicated would be practically useless for the analysis of the products of combustion of many water residues.Although the work professes to cover analysis for L L technical purposes,” it con- tains no reference to the chemistr softening processes. The examination of STOCKS, F.I.C. 1912. Charles Griffin and Co. Price 4s. 6d. net.REVIEWS 483 sewage and effluents is frequently mentioned, but the methods favoured in the laboratory of the Royal Commission on Sewage Disposal,$’ are not described, and, although a table of standards for effluents is given, the proposed standards of the Commission are ignored.From a careful perusal of thevolume, it appears that Public Analysts and others must still remain contented with some of the works on water analysis already on their bookshelves. WILLIAM T. BURGESS. TABLES ANNUELLES INTERNATIONALES DE CONSTAXTES ET DONNEES NUMERIQUES.Vol. I. Annee, 1910. Gauthier, Villars, Paris ; Akademische Verlags- gesellschaft, m. b. H., Leipzig ; J. and A. Churchill, London; University of Chicago Press, Chicago. 1912, xxxix + 727. Cloth. 24s. net. The need of collecting physical data has made itself increasingly felt, and prob- ably the chemist has experienced the want of a handy book of reference even more than the physicist.The latter is concerned, generally speaking, more with the methods by which a property is determined, the limits of accuracy attainable, and, above all, the correlation with other properties; the chemist, on the other hand, usually has in view the connection between tbe constitution of certain chemical com- pounds and some particular property. The physicist may have considerable trouble in searching scientific literature with regard to some physical property, but it is light when compared with that of the chemist, who, having some particular group of com- pounds under review, wishes to compare the values of some particular property.He has to find out for which of the compounds in question the value has been deter- mined; secondly, when discrepant values of the constant are given by different observers, to judge which value is the more reliable.In fact, whilst methods for determining some constant will be found described in a comparatively small number of researches, the values of this constant for different substances may be scattered throughout chemical literature. Organic chemistry has its Beilstein ” and ‘‘ Richter,” physical chemistry its ‘<Landolt and Bornstein”; the latter does not, however, claim anything like the completeness of the organic works, and to remedy this defect the subject was venti- lated at the Seventh Congress of Applied Chemistry, an International Committee nominated, and the table of constants for the year 1910 is now published under the patronage of the Association Internationale des Academies.Values of constants have been accumulated by a large number of abstractors. From the list it will be noticed that the British Empire and Germany have con- tributed at least two-thirds of the total. The results have been passed on to a relatively small number (thirty-one) of compilers, all men of established reputation. The British members of this shorter list are Messrs.S. L. Archbutt, H. B. Hartley, A. W. Porter, L. J. Spencer, and N. T. M. Wilsmore. Since the foreign compilers are generally of the same status, it will be seen that the work has been placed in reliable hands. Tho titles of the chapters given on p. 21, and the table of contents of pp. 22-39, make it, * Fourth Report, Vol. IV., Part V., 1904.The principles underlying the general classification are not quite obvious,484 REVIEWS easy to search for any particular property ; but why diffusion, degree of association, solubility, and similar matters should be dealt with after optical, electrical, and magnetic properties have been given, and be separated completely from coefficients of compressibility, density and viscosity, with which the work opens, passes the comprehension of the reviewer.Again, details relating to crystallography and mineralogy are sandwiched in between adsorption and organic chemistry, whilst mechanical and other properties of metals and alloys come later in the book. No harm is done, for material is found without much difficulty ; but the lack of arrange- ment is to be regretted in a work on which so much pains has been bestowed.The data given are at least as full as one would have expected, and the attempt has been made to record most of the significant figures. Taking a case at random, the densities of solutions of lithium nitrate were determined by Appleby in connec- tion with work on the viscosities of aqueous solutions of this salt, and no less than forty-nine density measurements taken from his work are recorded, in addition to a single value given by Himbach and Wintgen. A wise discretion has been exercised in the metallurgical portion ; the results of tests (tensile, torsion, etc.) are only recorded for materials of which an analysis has been made. A few matters which had escaped notice in the main part of the work are dealt with in a short supplement. No index is given ; the table of contents renders this scarcely necessary. The care taken in abstracting and compiling is viorthy of the highest praise, and the printing and general get-up are excellent. J. T. HETVITT.

ISSN:0003-2654    

DOI:10.1039/AN9123700482

出版商:RSC    

年代:1912

数据来源: RSC