摘要:

THE ANALYST. MAY, 1904. OBITUARY NOTICE. THE LATE DR. A. P. AITKEN. IT is with much regret that we record the death, on April 19, of Dr. Andrew Peebles Aitken, an old and honoured member of the Society of Public Analysts. Dr. Aitken was, perhaps, best known as consulting chemist for the last twenty-seven years to the Highland and Agricultural Society of Scotland, to whose Journal he was a constant contributor of valuable papers connected with agricultural chemistry. He was also a contributor of occasional papers to the proceedings of the Society of Public Analysts published in this journal.' Dr. Aitken was a native of Edinburgh, and was educated at its University, where he took the degrees of M.A. in 1867, B.Sc. in 1871, and D.Sc. in 1873. On leaving the University of Edinburgh he studied at Heidelburg, and on hia return to this country was appointed assistant to Professor Crum Brown and Demonstrator of Practical Chemistry in Edinburgh University.He was afterwards appointed Professor of Chemistry in the Royal (Dick) Veterinary College, Edinburgh, which post he held up to the time of his death. Under the Sale of Food and Drugs Act he was Public Analyst for the counties of Berwick, Hadding- ton, Peebles, Nairn, Ross, and Cromarty, and for sundry boroughs therein. PROCEEDINGS OF THE SOCIETY OF PUBLIC ANALYSTS. THE monthly meeting of the Society was held on Wednesday evening, April 13, in the Chemical Society’s Rooms, Burlington House. The President, Mr. Thomas Fairley, occupied the chair. The minutes of the previous meeting were read and confirmed. A certificate of proposal for election to membership in favour of Mr. J. H. Ball, B.Sc., was read for the second time ; and certificates in favour of Mr. Lewis Gordon Paul, Ph.D, (Tubingen), F.I.C., Market Hall Chambers, Huddersfield, Public Analyst for the Borough of Huddersfield, and Mr. Arthur Edgcome Brown, B.Sc. (Lond.), 13, Baronet Road, Tottenham, chief assistant to Mr. R. H. Harland, and Gas Examiner to the Enfield and Tottenham Urban Sanitary Councils, were read for the first time. Messrs. J. E. Jenkins, A. R. Tankard, A. Tighe, and F. L. Watt, A.R.C.Sc., were elected members of the Society. The following paper was read : “ The Microscopic Examination of Metals,” by J. H. B. Jenkins and D. G. Riddick. The paper was illustrated by lantern slides.

ISSN:0003-2654    

DOI:10.1039/AN9042900141

出版商:RSC    

年代:1904

数据来源: RSC

摘要:

142 THE ANALYST. NOTE ON ANALYSIS OF JAMS. BY RAYMOND ROSS, F.I.C. (Read at the Meeting, February 3, 1904.) WHEN in a sample of jam the presence of an adulterant, such as apple pulp, has been recognised by the usual microscopical methods, it is, I believe, almost impossible to determine with any degree of accuracy the quantity of the adulterant which has been added to the jam, I have been able to find very little literature bearing upon the subject. The ANALYST only contains five references to the matter in question, and in one of these contributions Mr. Adams gives analyses of a large number of jams ; but, as he him- self points out, no very definite conclusions can be drawn from them (ANALYST, vol. ix., p. 102). In a table by Konig on the analysis of seed fruits which is given in Wynter Blyth’s book on food analysis, it is observable that the percentage of woody fibre varies considerably in the different fruits.Thus, apple, according to this authority, contains 1-98 per cent. ; strawberry, 2.32 per cent. ; raspberry, 5.9 per cent. ; black- berry, 5.21 per cent. of woody fibre. It must be borne in mind that the skin of apple is included in this analysis. It is evident that these differences would have been accentuated if the woody fibre had been determined on the moisture-free sample. Although, owing to the process of manufacture, the fruit in jams has under- gone considerable change, it seemed to me probable that if the woody fibre were determined on the sugar and moisture free sample these differences would be main- tained.I therefore determined to treat a number of jams in the following manner : About 100 grammes of the jam was boiled with 500 C.C. of water for one hour, then filtered through linen with the aid of a filter-pump, and washed with about 250 C.C. of boiling water. I n the case of stone fruits the stones were then carefully removed, the resultant pulp of skin and seeds was dried for twenty-four hours in the water-oven, and the woody fibre determined on the dried sample as follows : About 0.5 gramme of the dried pulp was boiled with 50 C.C. of a 5 per cent. solution (by weight) of sulphuric acid, and 75 C.C. of water on a hot-plate for thirty minutes, filling up to the original bulk every ten minutes with hot water. After filtering through linen and washing with boiling water, the residue was washed back into the beaker, treated with 50 C.C.of 5 per cent. caustio soda, solution (by weight), made up to 125 c.c., and boiled exactly as above; then filtered through linen, and washed till free from alkali. The residue was then washed into a tared platinum dish, evaporated to dryness, thoroughly dried in the water-oven, and weighed. I have given the above process in eome detail because, as it is purely empirical, it is neceseary to adhere carefully to it if concordant results are to be obtained. Thus, I have proved that proionged boiling of the pulp with fresh quantities of water in many instances caused the reeults to be much higher than when the above method was adhered to. In some caees the determination of the ash was made on the residue, but no information of any value can be drawn from these figures.THE ANALYST.Tbe following table gives the results obtained : 143 Kind of Jam. Apple 11 , I P ? Turnip S l Marrow 1 9 Raspberry 11 11 l # 9 1 ? ? ? l Plum Blackberry Black currant Gooseberry Apricot 9 3 ? ? 9 9 11 3 ) $ 9 11 Strawberry Damson 9 1 $ 9 ? 9 Cherry 9 ) Woody Fibre. 9.4 9.7 10.5 14.0 13.4 16.0 10-8 16.0 44.5 44.0 46.0 58.0 58.0 65.0 68.0 12.5 12.5 33.0 33.0 36.9 33.0 54.0 54.0 20.9 20.8 26.0 28-0 45.0 40.3 8.3 10.4 10.4 19.0 24.0 Ash. 0.62 - 1.02 - 1.76 3.9 3.8 3.9 0.84 1 *72 3.06 1 -96 - - - - - 2.5 2.8 3.45 3.5 1 *22 2.6 - - It will be observed that, with the exception of plum and damson jams, the per- centage of woody fibre obtained is lower in the case of apple, turnip, and mmow jams than in any of the other jams experimented upon; and it is the difference thus obtained which I think may prove useful in determining the percentage of these adulterants. The first three raspberry jams undoubtedly contained some quantity of apple pulp, and, taking 58 per cent.of woody fibre as the minimum for raspberry, and 14 per cent. of woody fibre as the maximum for apple, this would give the percentage of added apple as about 30 per cent., calculated from the following formula : (Percentage of woody fibre of raspberry - percentage of woody fibre of sample) 100 Difference betiween percentage of woody iibre of raspberry and apple144 THE ANALYST. As Nature is by no means constant in the quality of her products, such a small number of determinations as I have been able to bring before you cannot in them- selves carry any very complete conviction, and I have, only brought this method before the Society as a suggestion, in the hope that by further development it may in time come to be of some help in the andysis of jam.In conclusion, I wish to thank my pupil, Mr. Joseph Race, for his able assist- ance in connection with the analyses given in this paper. DISCUSSION. Mr. BOSELEY said that some makers who used apple pulp were not, he believed, by any means particular that it should contain all the apple. In such cases they boiled the apples first, and then filtered through bags, with the result that the whole of the juice was extracted from the fruits, and where this was the case it would, he thought, be difficult to obtain reliable results by determining the quantity of woody fibre in the jam.He thought that a method based on a determination of the organic acids present would probably answer best for the purpose, or, at any rate, that some investigation in this direction might be made with advantage. He believed that turnip and marrow were practically never used for jam adulteration, as their large proportion of water and want of gelatinizing properties would render them quite useless for the main object in view, which was to hold up as much water as possible. Apples, of course, contained large quantities of pectinous matters, and were therefore well suited to impart setting power. Mr. Ross said that the method was intended merely for the detection of apple pulp,. and not of the apple juice which was added to jam, in what was generally regarded as a legitimate manner; and in some, at any rate, of these samples the evidence of the presence of apple pulp was conclusive. He was afraid that the successful working of a method on the lines suggested by Mr. Boseley would demand a knowledge, not only of the proportion of organic acids, but also of the amounts of sugar and fruit that had been used, and such knowledge, of courBe, would practically never be obtainable. He might repeat that, in the process he had just described, the fibre determination was made after the elimination of sugar, juice, etc., and was therefore independent of variations in those respects.

ISSN:0003-2654    

DOI:10.1039/AN9042900142

出版商:RSC    

年代:1904

数据来源: RSC

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144 THE ANALYST. ON THE ESTIMATION OF MORPHINE I N OPIUN. BY PHILIP SCHIDROWITZ, PH.D. (Read at the Meeting, March 2, 1904.) THE number of processes for the estimation of morphine in opium is legion. The object of by far the greater number of these processes is either to set up an official standard of analysis, or to attempt the determination of the total quantity of morphine present. The recognised official methods, however unsatisfactory they may be, are obviously important from a conventional and legal point of view. Rigid processes for the eetimation of total morphine are, in view of the varying composition andTHE ANALYST. 145 frequent adulteration of opium and of the present state of our knowledge, almost bound to fail. I n the present paper I am not concerned with either of the above-mentioned aspects of the question of opium analysis. Persian opium is sold and purchased almost entirely on analysis.The price varies with the morphine contents, but it must not be assumed that the value of the opium stands in direct ratio to the percentage of morphine. As a rule, contracts are made on a basis of not lees than 10 per cent. of morphine. . I t is obvious, therefore, that the eommercial analysis of opium is a very important matter, involving, as it does, the price and the acceptance or rejection of goods to the value of many hundreds of thousands of pounds annually. The details of the process, according to which, apparently, the greater part of the opium imported at present is assayed, are not known. That is to say, it is an unpublished process.I wish distinctly to say that I have no desire to question or to criticise the propriety of keeping the details of a purely commercial process-a process which may be a valuable business asset-undivulged. The process which I shall describe below was devised solely with the object of ascertaining the commercial value of opium, and with immediate reference to existing commercial conditions and requirements. I am not, of course, in a position to state that my process gives results identical with those obtained by the unpublished process, for the obvious reason that I have not been able to experiment with the two processes side by side ; but I can say definitely that I have the best reason for believing that my method yields results which are entirely satisfactory from a practical commercial point of view.Incidentally, how- ever, in the course of my work, I was able to obtain a number of figures relating to the analysis of samples by the unpublished process, which are printed below in conjunction with the results obtained from the same batches of opium by my own process. I may say here that the numbers relating to results obtained by the unpublished process were put at my disposal after I had recorded my own figures. The new process is to a certain extent based on the Pharmacopoeia Germanic& IV. method, but is simpler than the latter, and, owing to the modifications intro- duced, gives substantially different results. Six grammes i of opium (previously roughly powdered) are weighed into a small porcelain dish, 6 C.C. of water 1 are added, and the whole allowed to stand for about fifteen minutes. The contents of the dish are then worked up to an even creamy consistency by means of an agate pestle, and are then transferred (by means of successive small quantities of water) to a 100 C.C.Erlenmeyer flask, the latter having been previously counterpoised. The total weight of opium and water is then made up to 54 grammes. The flask, after corking, is shaken vigorously for five minutes, and ie then allowed to stand for one hour, with an occasional brief shaking. The I think I may say that I have succeeded in attaining this object. The process is as follows : * For Persian opium. t KO preliminary drying is, as a rule, necessary. If the opium is very wet and of low grade, i t is better t o dry off part of the moisture a t a low teml'erature (30' to 40" C.), or, preferably, a t the ordinary temperature, in a vacuum.Of course, distilled water is employcd throughout.146 THE ANALYST. contents are then filtered through a plain filter,' 10 amtimetres in diameter, into a second previously counterpoised 100 C.C. Erlenmeyer flask. If the filtrate does not run clear at first it must be returned to the filter. When exaotly 42 grammes of filtrate have been collected filtration is stopped. To the 42 grammes of filtrate are then added exactly 2 grammes of a solution of salicylate of soda in water, containing 50 grammes of salicylate per 100 C.C. The whole is then shaken for about half a, minute, and thereafter immediately filtered as before.Of the filtrate 36 grammee are collected, and to these are added 15 C.C. of ether, and, after rotating the flask once or twice, 5.2 C.C. of a solution of ammonia, prepared by mixing 17 grammes of ammonia (specific gravity 0.960) with 83 grammes of water, The whole is theu vigorously shaken for ten minutes,t and the flask and contents are subsequently kept for twenty-four hours at a temperature of 12" C. After this, as much of the ether as is possible is poured off through a filter 8 centimetres in diameter, 15 O.C. of fresh ether are run into the flask, the latter rotated briskly (but 80 aa to avoid forming an emulsion), and the ether again poured off through the filter. After this the whole of the liquid is poured through the filter, the greater part (roughly two-thirds) of the crystals, however, being retained in the flask.The flask and filter are then washed with three lots of 5 C.C. each of water saturated with ether, and delivered from a pipette. Of each 5 c.c., 3 C.C. are used to rinse the flask, and 2 C.C. are run directly on to the filter. The filter with its contents is removed from the funnel, folded, and gently but firmly pressed between sheets of filter-paper. The filter is then opened, and the greater part of the crystals are returned to the flask. Filter and flask are then placed in an air oven at 55" until dry. I t is then perfectly easy to tranefer the small quantity of crystals still adhering to the filter to the flask. Subsequently the crystals are dissolved in 25 C.C. & H,SO,, and the excess of acid titrated with & alkali, using methyl orange as an indicator.I t is preferable, prior to this titration, to dilute the liquid to roughly 50 c.c., and to fix the end-point by means of the droplet method. Let x = number of C.C. & acid employed, then x x 0.7575 + ?3 (5 x 0.7575) = per cent. morphine. The following tables give the results obtained by the process described above and by the unpublished process respectively, and from the same lots of opium. I may add that the figures given comprise all the analyses concerning which I was able to institute a comparison between the two processes. The figures are disposed, for the sake of convenience, in four groups, as under : The percentage of morphine in the sample is then calculated as followa : A.MORPHINE PERCENTAGE, UNDER NINE. Nnniher. Author's Process. Un ublislied Wocess. 1. ... ... ... 7.53 ... ... ... 8.40 2. ... ... ... 8-66 ... ... ... 8.60 3. ... ... ... 8.90 ... ... ... 9.10 4, ... ... ... 8.90 ... ... ... 9.00 * I prefer to use C.S. and S. quantitative filters. t It is essential that the corks with which the Erlenmeyer flasks are provided shohld fit perfectly. It is well to prelme thesc corks previously by soakiug them for a few hours in water containing a little sther.THE ANALYST. 147 B. MORPHINE PERCENTAGE, NINE TO TEN. Number. 5. 6. 7. 8. 9. 10. 11. 1.2. 13. Number. 14. 15. 16. 17. 18. 19. ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... hut hor ’s Process. 9.00 9.14 9.30 9.32 9.50 9-65 9.68 9-70 9-70 Ua ublished froces.... ... ... 9-40 ... ... ... 9.00 ... ... ... 9.45 ... ... 8.75 ... ... ... 9.50 ... 10-40 ... ... ... 9.70 ... ... ... 10.10 ... ... ... 9.70 ... ... C. MORPHINE PERCENTAGE, TEN TO ELEVEN. Author’s Process. ... . 10.00 ... ... ... 10.09 ... ... ... 10.27 ... ... ... 10.65 ... ... 10.87 ... ... 10.90 ... ... Un ublished J’rocess. ... ... ... 10.10 ... ... ... 10.50 ... ... ... 10.20 ... ... ... 10.10 ... ... ... 11.20 ... ... ... 12.50 D. MORPHINE PERCENTAGE, ELEVEN TO TWELVE. Author’s Unpublished Nuni ber. Process. Process. 20. ... ... ... 11.30 ... ... ... 12.00 ... 11.50 21. ... ... 11.50 ... ... 11.80 22. ... ... 11.63 ... 23. ... ... ... 11.66 ... ... ... 10.75 24. ... ... ... 11.80 ... ... 12.00 25. ... f . . ... 11.82 ...... ... 11.90 ... ... ... ... ... The following figurea (E) were obtained by the analysis of a group of samples received from a different quarter than tho80 under A to D, and I have the best reason to believe that the agreement of the figures with those yielded by the unpublished process was very good : E. AUTHOR’S PROCESS. Number. 26. ... ... ... ... ... 27. ... ... ... ... ... 28. ... ... 29. ... ... ... ... ... 30. ... ... ... ... ... 31. ... ... ... ... ... ... ... .., Morphine. Per Cent. 8.10 9.35 9-65 10.24 1 1 *oo 11 -82 I think it will be admitted that the results obtained by the two processes are in excellent accord. In a very few instances (e.g., Nos. 1, 19, and 23) there are apparently serious differences, but these, I think, are very possibly due to errors in sampling, such errors, as is well known in the trade, being very likely to occur, especially in high-percentage opiums, unless the very greatest care is taken in drawing the sample.148 THE ANALYST.I t will be noticed that only in two instances do samples which show more than 10 per cent. by one method yield less than 10 per cent. by the other. I n both cases the lower figures were obtained by my process. The average difference between the two methods is as nearly as possible 0.2 per cent., the new process showing the lower result. I may add that results obtained by another operator using my process were in very good accord with my own, the mean difference being 0.1 to 0.2 per cent. The analyses recorded above only represent a small part of the work which finally led me to the process described.I think it will not be without interest to add a short table recording a few comparative results obtained with different methods at the com- mencement of my investigation : F. RESULTS OBTAINED FOR SANE SAMPLES HY DIFFERENT PHOCESSES. Loof. 1. 12.51 11.67 10.25 6.98 2. 10.01 8.75 8.75 5.77 3. 8.23 7.56 6-15 4.50 4. 12.35 11-55 10.26 ‘3.41 5. 10.92 11-66 10.06 7 *78 6. 12-42 11 -80 10.27 8.91 Number of United States British Sample. Pharmacopceia. Yharniacopia. Dietrich’ Unpublished Process. 10.20 9.35 8.50 11.10 11 -33 9.70 DISCUSSION. The PRESIDENT (Mr. Pairley) inquired whether the working of the process was affected by the other alkaloids present in opium, and whether it was possible that their influence might account for the large differences between the results given by different met hods.Dr. SCHIDROWITZ replied that he could not say to what extent those differences might be due to the influence of other alkaloids. The various processes, of course, differed very greatly in regard to the media employed, the degree of concentration, and 80 on, which were known to affect the solubility of the various alkaloids. The question of temperature was also important, and he believed that the satisfactory nature of his results from a practical commercial point of view was partly due to the fact that he advocated a rigid temperature for the crystallization of the morphine. He did not know any other process in which that was done. He had at first thought the Dietrich procew to be a good one, but in some cases very large differences had been found (to the extent of nearly 2 per cent. in one case) between its results and those considered to be commercially ~atisfact~ory . Mr. BEVAN asked how the results of Dr, Schidrowitz’s process agreed among thernselves. Dr. SCHIDROWITZ said that the agreement between duplicate determinations was very satisfactory, The average difference between the results of his own determina- tions and some he had had made by another operator was only about 0.1 to 0.2 per cent.

ISSN:0003-2654    

DOI:10.1039/AN9042900144

出版商:RSC    

年代:1904

数据来源: RSC

摘要:

THE ANALYST. 149 ANALYSES OF POTABLE SPIRITS USED BY THE NATIVE POPULATION I N INDIA. BY HAROLD H. MA". THERE are very few analyses of distilled liquor, as prepared by native methods in India, on record, or at any rate accessible. This is the more remarkable as the extremely serious physiological effect of these spirits has long been noticed, and has been currently attributed to the addition, by the retailers of the liquor, of various noxious drugs, especially hemp (ynizj~~). I t has seemed, therefore, of importance to obtain analyses of a series of samples of liquor, as sold by the retail dealers of India, in order not only to ascertain whether the current opinion as to the presence of alkaloidal poisons derived from such drugs was well founded, but also to obtain information as to what is their composition with regard to the more usual con- stituents of distilled liquor.In the following preliminary series of analyses of spirits, which were all obtained in Bengal and Assam, only the more ordinary constituents have been determined. The higher alcohols have been estimated by the German official method, revised by Rose. As this method has been recently severely criticised by Schidrowitz," I hope to repeat the determinations on a fresh series of samplee, by the method which he prefers, on my return to India. Every sample has been tested for alkaloids (which have, however, been uniformly found to be absent) and many for furfurol (by means of the colour reaction with anilin), and this is found to be a constant by-product. I hope shortly to go carefully into the question of the quantity of both furfurol and aldehydes, to which great importance is attached, from a physiological point of view, by recent workers.I The samples I have obtained may be divided into four classes : 1. Those derived from nicrlma-that is, from the flowers of Bassia latifolin. 2. Those obtained from rice.' 3. Those from the refuse of sugar manufacture. 4. Those representing imported foreign low-grade spirit, imported, it seem8, chiefly from Germany. 1. This comprises ?uahita spirit, by far the most important class in Bengal and in , h a m the first. The ~inhua flowers used for the purpose are exceedingly rich in sugar, and may, as bought, contain as much as 58 per cent. of fermentable sugars (on the dry matter present).The fermentation and distillation are extremely crude, and the former is carried out in such strong solution that complete fermentation rarely takes place. The amount of total sugar in the liquor ready for fermentatiou may, in fact, reach 20 per cent. The yeast used is transferred from one batch of liquor to the next for a long time, and as the fermentation is never very vigorous, one would expect to find, as actually appears to be the case, a very large proportion of higher alcohols. I give first the actual The analyses of my samples gave figures as follows. * Jolcriisi~ ff the h c k t y of Chemical r%t!tLstrj, June 30, 1902. t Hewitt, JoiLrncd of thr Society qf C'hcwicnl Indiutry, January, 1902 ; Lauder b u n t o n and Tunniclifle, Lancet, December 8, 1900, and June 2, 1902.150 THE ANALYST.::* ' I percentage composition (except for the alcohol, which is reported as degrees under proof), and then the number of grains per gallon of proof spirit, in order to reduce the figures to a common alcohol basis. per Cent. TABLE I.-PERCENTAOE COMPOSITION. 0.004 0.003 0.010 1 0.008 0.002 0.002 0.001 X O . - 1 2 3 4 5 6 7 ~ 0.532 0.302 0.040 0-043 0.196 0.106 0.239 Source and Cost of Spirit. Calcutta, 1 pint, 9 annas* ... Calcutta, 1 pint, 9 annas ... Calcutta, 3 pint, 8 annas ... Calcutta, + pint, 8 annas ... Calcutta, + pint, 8 annas ... Assam ... ... 1 ) - . a ... No. 1 2 3 4 5 tj 7 Alcohol. ; Fixed Acids (as Tartaric). --- Degrees under Per Cent. Proof. 1 0-069 22.2 32.1 1 0.021 i I 48.3 None 57.8 i 0.027 39.5 i 0.042 64.9 i 0.035 63.2 0.033 Volatile Acids (as Acetic).Per Cent. 0.074 0.052 None 0.031 0.050 0.096 0.103 Solid Residue. Per Cent. 0,026 0.023 0.242 0.126 0.030 0.017 0.010 -I--- TABLE II.-COMPOSITION IN GRAINS PER PROOF GALLON. Source. Calcutta 1 9 1 9 1 1 9 9 Assam 1 , . ._ Fixed Acids (as Tartaric Acid). 62.1 21.7 None. 44.1 72.6 70-0 62.8 Volatile Acids (as Acetic Acid). 66.6 53.6 None. 50.7 87.1 191.5 195.9 Solid Residue. 23-4 23.7 327.7 206.0 51-8 33.9 19.0 -- Ash. -- 3.6 3.3 13.5 13.1 3.5 4.0 1.9 Higher Alcohols. 298.5 311.0 54.3 72.1 226.6 211.0 623.1 ~ - - The two samples from Aasam are not made from mahua flowers alone, but a variable proportion of crude locally-made sugar (ghztr) is mixed into the liquid obtained. 2. Rice Spirit.-Only one sample of spirit made from rice has come into my hands; it was purchased under the name Donsta in Calcutta, and gave the following figures : In Bengal it is usual to uae only maha flowers.TABLE III.-PERCENTAGE CONPOSITIOX. No. j Sonrce. ! I Alcohol. ' Fixed Acids. 1 v~~~~~ ISvlid KEaidue.1 Ash. 1 E&!t::s. ~- I--------- -!-- Degrees , under Proof. Per Cent. I Per Cent. I Per Cent. I Per Cent. I Per Cent. 8 i Calcutta 20.8 0037 I 0.084 I 0.017 I 0.003 I 0.561 * One anna equals one halfpenny nearly.THE ANALYST. 151 No. TABLE IV.-COMPOSITION IN GRAINS PER PROOF GALLON. - -- ~. - -____ Source. Fixed Acids. ----- - - - ~ No. 8 1 Calcutta 32-7 74.2 15.0 I 2.5 I 491.8 3. Spirits from Sugar Rsfuse.-These were two in number, and were in bottles labelled (6 Shajehanpur Rum.” TABLE V.-PERCENTAGE COMPOSITION.Source. Alcohol. ----- Degrees under Proof. Per Cent. 0.539 0.231 Fixed Acids. -- Per Cent. Traces. 0.006 Per Cent. 0.010 0.008 Volntile Acids. ~ _ _ _ Per Cent. None. 9 9 11 12 - I I Degrees under Proof. ~ Calcutta 58.7 ’ 9 9 58.0 Solid Residue. Per Cent. None. , Ash. Per Cent. I’er Cent. Per Cent. 1-52 0.02 0.217 H i g h r Alcoliols. 9 9 ’ 1.17 -- I-- 0.01 0-244 No. Source. Fixed Acids. Volatile Acids. Solid Residue. Ash. -----____ 11 i Calcutta None. None. 2576.3 34.9 12 ‘ 9 9 ,? 9 9 1950.0 16.7 TABLE V1.-COMPOSITION IN GRAINS PER PROOF GALLON. Higher Alcohols. 367.5 407.4 KO. Source. ’ Fised Acids. ~ Volatile Acids. Solid Residue. ’ Ash. 1 Higher Alcohols. -I----- 1- , 9 Calcutta Traces. I None. , 788-0 15-0 1 226.5 10 1 9 , 9.6 1 9 9 370.0 ; 12.2 261.6 I 4.Imported Low Grade Spirits.-These are characterized by the presence of an enormous quantity of organic solid matter (sugar) and a high percentage of higher alcohols. The figures are as follows : No. 11 wa8 marked “ Deer Brand Brandy,)’ and No. 12 as “ Thistle, Scotch Whisky.” TABLE VII.-PERCENTAQE COMPOSITION. No. Source. Alcohol. Fixed Acids. yJ$:!e Solid Higher ~ ~ ~ 1 1- Residue. I Ash’ 1 Alcohols. -- ---- - - - ~ - Per Cent. None. ) ) TABLE VIII.-COMPOSITION IN GRAINS PER PROOF GALLON. The chief points brought out by the figures thus set out, are : 1. The extreme dilution at which the spirit is sold. Only two ,samples slightly152 THE ANALYST. exceed 25 degrees under proof, while the bulk of the liquor is sold more than 50 degrees under proof.3. The large proportion of volatile acids in the spirits prepared by native methods from m a h a or rice. This is, of course, the natural result of the extreme impurity of the yeast used, and of the high concentration at which the liquors are usually fermented. 3. The large proportion of fixed acids, for which I have not yet been able to give an explanation. 4. The enormous percentage reached by the higher alcohols (fuse1 oil). Though the great physiological effect of these higher alcohols is now denied, yet it can hardly be that the enormous proportions indicated by many of my figures can be without injurious influence. 5. The total absence of alkaloids iri all cases. 6. The presence of furfurol in every spirit in which it was tested for, except one of the samples of " Shajehanpur rum." I hope to return to the subject, with further data concerning a larger number of samples, as well as other constituents such as the aldehydes and furfurol, which have been recently shown to be of considerable physiological importance. The actual analytical figures were obtained for me by Dr. C. Schulten, to whom I beg to tander my best thanks for his interest in the investigation.

ISSN:0003-2654    

DOI:10.1039/AN9042900149

出版商:RSC    

年代:1904

数据来源: RSC

摘要:

152 THE ANALYST. A R.\PID ACCURATE METHOD FOR THE VOLUMETRIC ESTIMATIOK OF CARBON DIOXIDE. BY THOMAS MACARA. THIS process is based on the fact that BaCO, behaves like an alkali towards methyl orange. The apparatus employed consists essentially of : 1. A decomposing flask, A (see sketch), fitted with a stoppered funnel, C, and an exit tube. 2. An absorbing flaek, B, fitted with an inlet tube, D, and a safety funnel, E, which also acts as an exit tube. Tlw necessary solutious are : ((7) A cold saturated solution of Ua(HO),. ( b ) or i\ HC1. (c) Dilute HC1 (1 : 5 ) . ( d ) Indicators, phenolphthalein and methyl orange. Method of I-roccditre.-A known quantity (equivalent to not more than 2.5 grammes CaCO,) of the sample ia introduced into A, and H,O, free from COB, added until only sufficient space is left to prevent the contents boiling over after the addition of the acid.(If the air-space left in the flask is considerable, much longer boiling is required to drive out the last traces of CO,.) A considerable excess of Ba(HO), solution is placed in flask B, and to this 2 or 3 drops of phenolphthalein arc3 added, a little of the mixture being used to seal the safety funnel 13.THE ANALYST. 153 A and B are now connected, and an excess of acid (either HCl or H2S04) is cautiously run into A through C, and the contents of A gradually raised to boiling- point and kept at that temperature until nothing but steam appears to be passing into B. During the evolution of gas B must be kept vigorously shaken in order to assist the absorption of the gas.If the shaking has been sufficiently vigorous all the CO, will be found in B, none or only traces being found in E. As soon as all the CO, has passed over, the flasks are disconnected. An ordinary small funnel is now attached to inlet tube D, and dilute HC1 run into B until all the free Ba(HO), has been neu- tralized. Two or 3 C.C. of Ba(HO), solution are then added to make the contents of B alkaline, and the flask is well shaken to insure the absorption of any liberated GO,. The cork is removed, and the contents of E are rinsed into B, while any BaCO, adhering to the tubes is rubbed off and added to the bulk. The excess of the hydrate is now neutralized with 4 HC1 (-& where special accuracy is required), and 2 or 3 drops of methylorange added.The BaCO, is then titrated with standard acid. If, as sometimes happens when the flask has not been sufficiently shaken during n F absorption, a few scales of BaCO, remain undissolved, the contents of the flask are heated and the titration finished by adding the acid drop by drop till the solution remains pink after boiling for a short time. The usual precautions are necessary when H,S, SO,, Ci, Br, and oxides of nitrogen are present--e.g., CuSO, should be added to the flask before the acid when sulphides, chromate when sulphites are present. In the latter case H,SO, should, of course, be used, as HC1 is apt to give off Cl when boiled even with moderately dilute solutions of chromate, etc. As to the accuracy of the process, this is only limited by the delicacy of the indicators, and even this can in most cases be increased considerably by using larger quantities of the sample. In this way the merest traces of GO,-e.g., as in such substances as borax, calcined magnesia, and lime, eto.-can be accurately determined. It is only necessary to use a Iarge decomposing flask, with, say, 100 grarnmes of the sample, and a, small absorption flask, with only a small quantity of Ba(HO),, and using Fg acid for the titration. The whole process need not take more than fifteen to twenty minutes once the apparatus has been fitted up. A saturated solution of Ba(HO), keeps for a very considerable time in a stoppered Winchester quart bottle, no extra precautions being necessary ; any GO, absorbed falls to the bottom, and the clear Ba(HO), may be readily poured or drawn off.

ISSN:0003-2654    

DOI:10.1039/AN9042900152

出版商:RSC    

年代:1904

数据来源: RSC

摘要:

154 THE ANALYST. Morning {Evening ABSTRACTS OF PAPERS PUBLISHED IN OTHER 3 0 U R N A LS. 2.1 ,) 2.5 2-3 ,, 2.8 FOODS AND DRUGS ANALYSIS. (Oesterrekh. Chem. Zed., 1904, vii., 101, 102.)-The milk is passed through a filter made of the finest bolting-cloth (silk), the filter being previously moistened with water. The dirt collected on the filter is washed with water, then with alcohol and ether, and either dried before brushing off the filter into a weighing-vessel or washed off with water into a platinum basin, evaporated, and weighed. Of 502 samples of milk examined, 37 were dirty, and yielded by the above method from 6.9 to 110.5 milligrammes of dirt per litre of milk. The results of experiments with dry powdered cow-dung are given, which Determination of Dirt in Milk. M.Ball& show that the method is trustworthy. w. P. s. Composition of Goat’s Milk. P. Buttenberg and F. Tetzner. ( h i t . f6r Untersuch. der Nahr. und Genussmittel, 1904, vii., 270-272.)-The following table shows the variations in the composition of milk yielded by goats of different ages. The analyses extended over seven consecutive days : Age of Goat. Two years ... Two and a half years Three years ... Three years ... Five years ... Time of Milking. Per Cent. 3.8 to 4.4 4-9 ,, 5.6 3.4 ,, 3.7 4.0 ,, 4-7 Morning {Evening 3.1 ,, 3.4 Morning {Evening Non-fatty Solids. Per Cent. 8.82 to 9.07 8.59 ,, 8.99 8-19 ) ) 8.53 8.14 ,, 8-59 8.01 ) ) 8.43 8.18 ,, 8.52 8.02 ,, 8.23 7.91 ,, 8.38 7.13 ,, 7.71 7.37 ), 7.59 w. P. s. A New Method for Determining Cocoanut Oil in Butter. E.Polenske. (Zeit. fiir Udersitch. der Nahr. wid Genussmittel, 1904, vii., 273-280.)-The method described is based upon the determination of the volatile insoluble fatty acids which distil over in the ordinary Reiohert-Meissl procese. In order that concordant resultsTHE ANALYST. 155 may be obtained, the distillation must be carried out under certain conditions and in an apparatus of the dimensions of that shown in the illustration. For saponifying the 5 grarnmes of fat, 20 grammes of glycerol and 2 ca. of 50 per cent. sodium hydroxide solution are used. An alcoholic solution of the latter is to be avoided. After dissolving the soap and adding the requisite quantity of sulphuric :--- acid as usuaJ, the distillation is proceeded with. The flame is regulated so that 110 C.C.i of distillate axe obtained in from nineteen i to twenty-one minutes. The temperature ' of the condenser water should lie between 1 : 18" and 20" C. When 110 C.C. of distillate have been collected, the receiver is replaced by a 25 C.C. cylinder. Without mixing its contents, the receiver is placed in a bath of water at a temperature of 10" C . for ten minutes, the surface of the water being just above the 110 C.C. mark. The insoluble fatty acids rise into the neck of the flask, , and in the cage of butter form solid white opaque granules, whilst with pure cocoanut oil clear, oily drops are obtained. Mixtures containing more than 10 per cent. of cocoa- nut oil also yield oily droplets. After mix- ing and filtering the contents of the flask, the Reichert-Meissl value is determined on i 7 XI 7 the filtrate.The condenser, cylinder, and receiver are washed with 18 C.C. of water, which are then poured over the filter. The insoluble fatty acids on the filter are now dissolved in alcohol, and the solution titrated with barium hydroxide soluiion, using phenolphthalein as indicator. The number of C.C. of i; barium hydroxide solution required is termed the " new butter-value " of the fat under examination. Thirty-one various samples of butter, having Reichert-Meissl values between 23.3 and 30.1, gave '' new butter-values " from 1.5 to 3.0. Four samples of cocoanut oil, with Reichert-Meissl values from 6.8 to 7-7, gave L c new butter-values " from 16.8 to 17.8. Numerous analyses of mixtures are also given, from the results of which it is Been that butters with Richert-Meissl values between 23 and 27 give '' new butter- values " from 1.6 to 1.9, or a rise of 1.0 in the former is attended by an increase of 0.1 in the latter.The " new butter-value " in the case of butters hrtving Reichert- Meissl values of 28, 29, and 30 increases more rapidly-2.2,2-5, and 3.0 respectively. The rise, of course, is still more marked if cocoanut oil be present. The method is approximately quantitative if the Reichert-Meissl value of the sample be also taken into account. w. P, s.156 THE ANALYST. Reichert- Meissl \'slue. (a). Detection of Cocoanut Oil in Butter and other Fate. A. Juckenack and R. Pasternack. (Zeat. fur Untersuch. der Nahr. und Gentusmittel, 1904, vii., 193- 214.)-Although the presence of cocoanut oil in butter is not readily shown by the usual constants obtained in the analysis of the fat, the authors point out that by taking the relation of certain of these constants to one another, and also determining the molecular weight of the soluble and insoluble fatty acids, the detection of cocoanut oil is rendered more certain.For instance, on subtracting the saponifica- tion value from 200, and further subtracting the result from the Reichert-Meissl value, a figure is obtained which in the case of pure butters varies from -3.39 to + 4.14. The mean molecular weight of the volatile soluble fatty acids of butter varies from 95.0 to 99.0, and of cocoanut oil from 130.0 to 145.0. The molecular weight of the insoluble fatty acids of butter lies between 259.5 and 261.0, whilst the insoluble fatty acids of cocoanut oil have a mean molecular weight of 208.5 to 210.5.The phytosterol-acetate test is also of great value for detecting cocoanut oil, or other vegetable oil, in butter. In the following table ;L summary is given of the results of the analysis of a few typical samples : Pure cocoanut oil gives a figure from - 46.98 to - 50.71. St~ponifica- tion Value. '' Difference " n - ( b - 300). (a). Pure butter.. . ... Butter containing 10 per cent. cocoanut oil . . . ... ... Butter containing 20 per cent. cocoanut oil.. . ... ... Three commercial butters containing cocoltnut oil ... 27.51 25-27 24.06 24.40 19.20 24.35 ---_____- ~- 223.37 + 4.14 226.96 - 1.69 230.22 - 6.16 232.24 - 7.84 230.50 - 11.30 235.83 - 11.48 Pliytosterol- wetate Test. - - - - - 121.2O C." 115*oo c.t Molecular U'eight of the Non-volatile Fatty Acids. 260.15 ~ _ _ _ _ 254.06 249.02 248.79 246.41 247.99 w. P. s. An Organic Phosphorus Compound in Natural Wine and Qrape Stones. J. Weirich and G. Ortlieb. (Chem. Zed., 1904, xxviii., 153, 154.)-A wine pre- pared from grapes grown in the island of Thyra was found to contain 0.095 per cent. of phosphoric anhydride. Other wines examined contained from 0-02 to 0.06 per cent. As the proportion of nitrogen in a wine varies almost directly with the phosphorus, it is probable that the latter is present in the wine in the form of lecithin or similar compound which has its origin in the grape- stones. Strong natural Southern wines contain more organically combined phosphorus than do artificially prepared wines.Pure wines are sometimes pasteurized to improve their * After fifth crystallization. t After seventh crystallization.THE ANALYST. 157 keeping properties, but this is not to be recommended, as lecithin is decomposed at a temperature a little above 50' C. w. P. s. A Simple Method for the Defection of Citric Acid in Wine. A. Devarda. (Zeds. landw. 'Versuchsw. in Osterr., 1904, vii., 1 ; through Chem. Zed. Rep., xxviii., 42.)-By means of the following method 0.2 to 0.25 per cent. of citric acid can be recognised with certainty in wine: The alcohol is first boiled off, and the wine diluted to its original volume; 50 C.C. are then shaken for one minute with 2 to 4 C.C. of a 10 per cent. solution of pure malic acid and 1 to 2 grammes yellow mercuric oxide, and immediately filtered.To 40 C.C. of the filtrate 6 C.C. of 95 per cent. alcohol and 2 C.C. of mercuric nitrate solution are added, the liquid is shaken up a little and then allowed to stand for a few minutes in cold water at 10" to 15" C. The mercuric nitrate solution used is prepared by adding 2 C.C. of glacial acetic acid to 16 grammes of che salt, and gradually making up to 100 C.C. with water. The precipitate produced by the mercuric nitrate is filtered off, and, after the liquid has drained away completely, it is treated on the filter with 15 C.C. of 7 per cent. acetic acid, without shaking. Of the total filtrate, 10 C.C. are then treated with 1.5 C.C. of lead acetate solution, prepared by mixing 4 parts of a cold saturated solution of lead acetate with 1 part of glacial acetic acid.After heating the whole to boiling, it is filtered rapidly through a small washed filter-paper, and the filtrate allowed to cool slowly to 10" or 12' C. If the wine contains no citric acid, the filtrate will remain clear on cooling ; at the most a slight precipitate of lead tartrate is obtained after some time, insoluble on warming. If citric acid is present, on the other hand, the liquid becomes milky and opaque, and the precipitate only settles after a long time. A. G. L. Detection of Tartaric Acid in Citric Acid. 0. V. Spindler. (Chem. Zed., xxviii., 148.)-The words ( ( 2 C.C. dichromate solution 5 : 1,000 " in the author's paper on the " Detection of Tartaric Acid in Citric Acid " (Chem.Zed., xxviii., 15 ; ANALYST, this vol., 118) should read '' 2 C.C. dichromate solution 5 : 100." A. G. L. Breakfast Foods. J. B. Weems and C. E. Ellis. (Iowa State Coil. Agric. BdZetin, lxxiv., l01-114.)-Analyses are given of thirty-four kinds of these cereal preparations. The results show that the statements printed on the packages as to the value of the foods are greatly exaggerated. The preparations do not possess any nutritive value in excess of ordinary food materials. The claims made for many of the " predigested " foods are valueless, and no reliance can be placed in the state- ments that they are remedies for any disease, these foods not being medicines. w. P. s. The Determination of Gliadin in Wheat Flour by means of the Polmimeter Harry Snyder. (Journ.A w r . Chent. Soc., xxvi., 263.)-For the polarimetric158 THE ANALYST. determination of gliadin, 15-97 grammes of the flour are extracted with 100 C.C. of 70 per cent. alcohol, the whole being shaken every half-hour for two or three hours and then allowed to stand for twelve to eighteen hours at a temperature of 20" C. The time of extraction may be shortened by using a shaking machine and clarifying the liquid by centrifugal action, but excessive shaking is to be avoided as tending to give cloudy filtrates. The extract is filtered and polarized, using a 220 millimetre tube. On multiplying the reading on the sugar scale by 0.2, values for the gliadin nitrogen are obtained which agree very well with those given by a Kjeldahl determination on the alcoholic extract.It appears that flour of good quality should contain 12 per uent. of total proteids (N x 6.25) or about 11 per cent. of protein (N x 5*7), and that from 55 to 65 per cent. of the protein should be in the form of gliadin. A. G. L. Determination of Xanthine Bases in Meat, Yeast, and other Extracts 11. In Yeast Extracte. (Zeit. fiir Untersuch. der Nahr. uiul Genuss- mittel, 1904, vii., 257-269.1-The process used wad similar to that previously described for the determination of xanthine bases in meat extracts (ANALYST, 1903, 315). The acid employed for the preliminary boiling was more dilute than in the case of meat extract, 300 grttmmes of yeast extract being boiled with 2,300 C.C. of water and 200 C.C. of dilute sulphuric acid (1 : 3). The hydrochloric acid solution of the bases obtained from the copper bisulphite precipitate, after removal of the copper, was evaporated, and treated with ammonia.At the end of twenty-four hours the precipitate (Fraction I.) was filtered off. The filtrate was then precipitated with ammoniacal silver solution, as already described, and a dry residue of the bases obtained. Twenty-three grammes of the latter were dissolved in 1,250 C.C. of hot water, and mixed with 2,000 C.C. of hot picric acid solution (11 : 100). After cooling to 25" C. the precipitate was collected on a filter (Fraction 11.). .By evaporating the filtrate to about 300 c.c., and allowing it to stand for twenty-four hours, a furthei quantity of precipitate was obtained (Fraction 111.). The filtrate from this yielded still another amount of bases (Fraction IV.).These various fractions were purified and examined. Adenine, xanthine, and traces of hypoxanthine were also present. Adenine was the only bast detected in Fraction 11. I n comparison with the other fractions, Fraction 111. contained the largest quantity of xanthine ; hypoxanthine, guanine, and a small amount of adenine also being present. Fraction IV. consisted chiefly of hypo- w. P. s. I(. Micko. Fraction I. was found to consist principally of guanine. xanthine, with traces of xanthine, adenine, and guanine. The Amount of Sand in Cayenne Pepper (Paprika). R. Windisch. (Zeit. laidw. Vewuchsw. in Oesterr., 1904, vii., 19 ; through Chem. Zeit. Bep., 1904, xxviii., 55, 56.)-Sorne samples of cayenne pepper contain abnormal quantities of sand, although when examined under the microscope they appear to be genuine.Genuine oayenne should not contain more than 1.5 per cent. of sand at the outside, 0.5 perTHE ANALYST. 159 cent. being the average quantity. sample is adulterated. When the amount exceeds 1.5 per cent. the The total ash, less sand, of cayenne varies between 5-62 and 8.01 per cent., with an average of 7.01 per cent. w. P. s. Determination of Colchicine. (3. Bredemann. (Apot. Zeit., xviii., 817 ; through Pharm. Jown., 1904, Ixxii., 246.)-The following method, which is a modi- fication of Katz and Kremel's, is described for the determination of the active alkaloid in colchicum seeds. The coarsely-crushed seeds are extracted by percolating with 60 per cent.alcohol until about 10 times their weight of tincture is produced. Fifty grammes of the latter are evaporated to about 20 grammes, 0.5 gramme of paraffin wax and 20 grammes of water are added, the mixture is warmed until the paraffin melts, and the heating continued to evaporate the alcohol and reduce the liquid to about 10 grammes. After cooling, the whole is filtered, and the cake of wax washed with 10 C.C. of water and 1 gramme of acetic acid. The mixed filtrates are saturated with sodium chloride, and shaken out with chloroform as long as any alkaloid is removed. The chloroform extracts are filtered and evaporated to dryness. The residue is redissolved in water, filtered if necessary, evaporated, and dried over sulphuric acid. Seven samples of seed were found to contain from 0.45 to 1.34 per cent.of colchicine, and four samples of corm from 0.32 to 0.60 per cent. The coarsely- powdered seeds are somewhat, if only slightly, more easily exhausted than entire seeds, and percolation gives better results than extraction in a Soxhlet apparatus. w. P. s. New Reactions for the Detection of Cocaine. C. Reichard. (c'hem. .%it., 1904, xxviii., 299.)-The following tests are described: A trace of titanic acid is heated with tt few drops of concentrated sulphuric acid until dissolved, and cooled. On adding a minute quantity of cocaine hydrochloride to the mixture, no change takes place while cold, but, on warming, a violet or blue coloration is produced, according to the amount of cocaine salt added. When a trace of cocaine hydrochloride is mixed with a little solid potassium-ethyl sulphate and a drop or two of concentrated sulphuric acid, a powerful peppermint odour is produced on heating the mixture.A further test consists in warming a salt of cocaine with sulphuric acid and an organic amide, such as urea or ethylene-diamine hydrochloride, when a deep blue coloration is produced. w. P. s. The Correction for Increase of Volume in the Determination of Morphine in Opium and Tincture of Opium. E. Dowzard. (Pharm. Joum., 1904, lxxii., 397, 398.)-In a method recently published for the analysis of opium (ANALYST, this vol., p. 91) 51% C.C. of filtrate are used for the determination of the morphine, 1.6 C.C. being taken as the increase in volume due to extractives. This figure was calculated from the British Pharmacopaeia correction, but experiments have since proved that the increase in volume is much lower than that given in the British Pharmacopocia.160 THE ANALY8T.Eight grammes of opium were treated with 100 C.C. of water and 3 grammes of slaked lime, ae previously described. Five C.C. of the filtrate were rapidly evaporated and dried at 100" C. in a current of air free from carbon dioxide. After weighing, the residue was ignited, and the ash obtained assumed to be all calcium oxide, and calculated into Ca(OH), per 100 C.C. This was subtracted from the total extractive in 100 C.C. to give the amount of opium extract. The volume of the Ca(aH), and opium extract are calculated from the data : 3 grammes of Ca(OH), displace 1.44 C.C. of water, and 3 grammes of opium extract 1.9 C.C.of water. The sum of these two reeults gives the volume of the soluble matters in 100 C.C. of the filtrate, and this volume subtracted from 100 C.C. shows the amount of water present in 100 C.C. From this ia calculated the volume that the original 100 C.C. of water has increased to. In the case of tincture of opium, the increase given in the previously mentioned paper (2 c.c.) was correct. If the final volume be made up to 102 c.c., 50 C.C. of the filtrate The average result of a number of experiments was 0.9 c.c., not 1.6 C.C. correspond to 50 C.C. of the original tincture. w. P. s. Notes on AndrB's Reaction for Quinine. E. LBger. (Joz~rn. Pliarm. Chim., 1904, xix., 281-284.)-The emerald-green coloration produced on treating a solution of quinine with chlorine or bromine water followed by a&monia is widely employed as a qualitative test.The author, however, shows that under certain conditions the results may be very different. For instance, if 10 C.C. of a eolution of 0.5 gramme of quinine in 1,000 C.C. be shaken with 0.5 C.C. of a mixture in equal parts of saturated bromine water and distilled water, a yellow precipitate is formed and immediately redissolved, and on now adding 2 drops of ammonia solution and shaking the tube the normal emerald-green coloration is obtained. If, however, 1 c.,c. of the diluted bromine water be added in place of 0.5 c.c., a gooseberry-red colour is obtained, which, on standing, gradually disappears and changes to bright green. Or if to the normal green liquid in the first tube an additional 0-5 C.C.of the bromine solution be added the colour at once changes to violet. Conversely, if a trace of sodium bisul- phite be added to the red liquid in the second tube the colour immediately becomes green. Again, if 2 C.C. of the bromine solution be used in the test a yellow precipi- tate is produced, which gives a yellow opalescence on shaking. The addition of ammonia renders the liquid clear, but does not change the colour either to red or green. Hence the author concludee that it is necessary to keep the amount of bromine constant in this reaction, whereas the proportion of ammonia may be varied within wide limits. By using 0-5 C.C. of a bromine solution consisting of 1 C.C. of saturated bromine water in 200 C.C.of distilled water, it is possible to detect 1 part of quinine in 20,000. By working under identical conditions the reaction may be used quantitatively, provided quinidine be absent. C . A. N. Reagent for Myrrh. Hirschsohn. (Pharm. Ztg., xlviii., 96 ; through Pharnt. Joiim., 1904, lxxii., 247.)-Genuine myrrh, when treated with trichloracetal-chloral hydrate, gives a fine violet coloration. This reagent is prepared by passing chlorineTHE ANALYST. 161 into 75 per cent. alcohol, if possible in direct sunlight, until the liquid becomes cloudy and separates on standing into two layers. The lower of these is separated, washed with water, treated with magnesia to remove free acid, filtered, and mixed with four times its weight of chloral hydrate. The product is a syrupy liquid which fumes slightly. As far as the author's experience goes, no other resin or gum-resin gives the same coloration as does myrrh. w. P. s. Detection of Turmeric in Powdered Rhubarb, J. Anselmier, (Schueiz. Wochenschr. C l i e ? ~ . Phrm., 1904, xlii., 119 ; through Chem. Zeit. Rep., 1904, xxviii., 80.)-This form of adulteration may be detected by shaking 0.1 gramme of the powder with 20 drops of olive oil for one minute. One drop of the mixture is then placed on a white filter-paper, when a. characteristic yellow ring is formed should turmeric be present. The ring given by pure rhubarb cannot be mistaken for that yielded by turmeric. w. P. s. Determination of Resin in Gum Scammony. E. Dowzard. (Phar??z. J O I l T I L . , 1904, lxxii., 469.)-The following method is stated to be quicker than the usual one of extracting the scammony in a Soxhlet apparatus: Two grammes of the finely- powdered satnple are placed in a tightly-corked flask; exactly 20 c.c of ether are added, and the flask gently shaken until complete disintegration has taken plmx. After standing for fifteen minutes, with occasional ehaking, the ethereal solution is passed through a dry filter. Ten C.C. of the filtrate are then evaporated in a tared vessel, dried at 100' C., and weighed. Allowance is made for the fact that each 0.1 gramme of resin increases the volume of the ether by 0.075 C.C. w, P. s.

ISSN:0003-2654    

DOI:10.1039/AN9042900154

出版商:RSC    

年代:1904

数据来源: RSC

摘要:

THE ANALYST. 161 ORGANIC ANALYSIS. Determination of Formaldehyde. C. Kleber. (Pluzrm. Rev., xxii., 94 ; through Pharm. Joiirn., 1904, lxxii., 428.)-To a concentrated solution of commercial sodium hydrogen sulphite, which generally contains a considerable quantity of free sulphurous acid, a solution of pure sodium hydroxide is added, until the odour of sulphurous acid ha8 completely disappeared. A slight excess of sodium hydroxide does not matter. The solution is then diluted with water until 30 C.C. of it exactly neutralize 50 C.C. of Towards this solution formaldehyde behaves like an alkali, and can be titrated accordingly. cv. P. s. sodium hydroxide, using phenolphthalein as indicator. The so-called “ Hydrocellulose.” Arthur Landauer Stern. (Joitrn. Chent. Soc.)-When cellulose is exposed to the action of dilute acids under certain conditions, the powder of so-called hydrocellulose” obtained is shown to have the same elementary composition as cellulose itself, and not to correspond to the formulaTHE ANALYST.C,, H,, 0,, usually assigned to it. A small amount of soluble matter, probably con- sisting partly of &glucose, is also formed at the same time. A. G. L. Dry Defecation in Optical Sugar Analysis. W. D. Horne. (Jounz. Amer. Cliem. SOC., xxvi., 186.)-The error in the polariscope readings due to tbe volume of the precipitate obtained by adding lead subacetate solution, and then diluting the liquid to 100 c.c., can be largely eliminated by adding solid lead subacetate to the sugar solution after it has been made up to 100 C.C.This procedure leaves the volume of liquid in which the sugar is dissolved practically unchanged, and avoids the troublesome corrections of the older method, the results obtained directly agreeing well with the corrected results of the wet method. With some refinery solutions the grains of lead subacetate tend to become coated with insoluble crusts, which prevent their solution ; this difficulty is readily overcome by adding coarse, dry sand with the lead salt before shaking. A. G. L. Determination of Starch by Hydrolysis with Hydrochloric Acid. A. Rossing. (Zeit. ofentl. Chem., 1904, x., 61-64.)--Two methods were tried, the first being the one originally described by Sachsse, and the second a modification of the same. According to the first method, 3 grammes of starch or meal were formed into a paste with 200 C.C.of water, 15 C.C. of hydrochloric acid of specific gravity 1.125 were added, and the mixture heated on a water-bath for two and a half hours. After cooling, the solution was nearly neutralized, made up to 500 c.c., and the dextrose determined in 25 C.C. by Allihn’s method. I n the modified process, 2 granimes of meal were made into a paste with 100 ac. of water, 15 C.C. of concentrated hydrochloric acid (specific gravity 1-19> were added, and the whole heated in boiling water under a reflux condenser for two hours. The solution was then cooled, neutralized, diluted to 250 c.c., filtered if necessary, and the dextrose determined in 25 C.C. as before. The starches used in the experiments were wheat, potato, rice, arrowroot, and maize.To obtain the correct amount of starch known to be present, it was necessary to use the factor 0.94, instead of 0.9, to convert the dextrose found in the first method into starch, and 0.93 in the second method. Neither method is suitable for determining starch and dextrin in baked foods, such as bread, etc. w. P. s. Tbe Hydrolysis of Maltose and of Dextrin by Dilute Acids and the Determination of Starch. William A. Noyes, Gilbert Crawford, Charles H. Juniper, Edgar L. Flory, and Robert B. Arnold. (Joum. Aiuer. C h i n . SOC., xxvi., 266.)-From the results of their investigation, the authors conclude that the hydrolysis of maltose and of dextrin does not proceed strictly in accord with the law of mass action, a retardation setting in after a time.Whilst dextrose itself is scarcely affected in its reducing power by heating with a 2.5 per cent. solution of hydrochloricTHE ANALYST. 163 acid, they find that with maltose a maximum reducing power is reached after one hour's heating at 100" C., or twenty to thirty minutes' at 111' C. This maximum reducing power corresponds to a hydrolysis of 96 to 98 per cent. With the products obtained by the action of extract of malt on starch a maximum reducing power is obtained at the end of one hour, amounting to 96.4 per cent. for a 0.5 per cent. solution of starch, and 97.1 per cent. for a 2 per cent. solution. By the direct treat- ment of starch with 2.5 per cent. hydrochloric acid (specific gravity 1.125) in a 0.5 per cent. solution, a, hydrolysis of 97 per cent.is obtained in one hour, and of 98 per cent. in four hours. For the determination of starch, the authors recommend that, after filtration, 10 per cent. by volume of hydrochloric acid (specific gravity 1-125) should be added to the solution obtained by the action of malt extract on the material. The whole is heated for one hour in a boiling water-bath, making allowance for the time necessary for the solution to attain the temperature of the batb, and, after cooling, enough sodium hydroxide is added to neutralize 90 per cent. of the acid present. The liquid is then rnade up to a definite volume, filtered if necessary, and the reducing power determined by Fehling's solution; 100 parts dextrose found represent 93 parts of starch in the original material.The authors emphasize that each chemist should determine for himself, with pure dextrose, the ratio between dextrose and copper oxide given by the method he uses. Their own determinations are not very con- cordant, differing amongst themselves by about 10 per cent. A. G. L. Rapid Estimation of Starch in Barley and Malt. H. T. Brown and Millar. (Trans. Gtiiniiess Kesearch Lub., I., 1903, 79-91 ; through Brewing Trade liev., 1904, xviii., 101.)-The ground grain is extracted with alcohol, then treated with malt extract, and the starch calculated from the cupric reducing power of the solution. Five grammes of the very fine flour are extracted in a modified Soxhlet apparatus with alcohol, of specific gravity 0,920, to remove all reducing substances and alcohol- soluble nitrogen compounds.Three hours' extraction is necessary in the case of barley and nine hours' for malt. To prevent frothing a little solid paraffin may be added to the extraction flask. The extracted flour is well boiled with 100 C.C. of water, cooled to 57" C., 10 C.C. of active malt extract are added, and the conversion allowed to proceed for 1 hour. The solution is then boiled, filtered into a 200 C.C. flask, the residue well washed, and the volume made up after cooling. The cupric reducing power of 20 C.C. of this solution is now determined, and the maltose calculated from the reduced copper after correction for reduction due to the malt extract (see Trans. Chem SOC., 1897, 94); 84.4 parts of maltose correspond to 100 parts of starch. A malt showing a diastatic power of 80 Lintner should be employed for making the cold malt extract.The moisture is also determined in the flour so that the results may be calculated on the dry material. w. P. s. The Detection of &naphthol in Benzonaphtbol. A. Jorissen. ( A ? m de Chint. m2nl., 1904, ix., 86, 97.)-According to the author, benzonaphthol as sold is164 THE ANALYST. not infrequently contaminated with P-naphthol. The test prescribed by the French Codex is to introduce a fragment of potassium hydroxide into a chloroform solution of the thoroughly dried drug, and to boil the liquid, which ought not to turn blue. I n the author's opinion the results of this test are sometimes doubtful. Another Codex test consists of mixing an alcoholic solution with an equal volume of nitric acid, and adding a few drops of a, solution of acid mercuric nitrate, which ought not to produce a cherry-red coloration. The following test is recommended as capable of detecting 1 per cent.of P-naphthol : 0.02 grsmme of the drug is shaken with 2 C.C. of glacial acetic acid, and 1 or 2 drops of nitric acid (63 per cent.) introduced. In the case of pure benzo- naphthol the liquid remains colourless, whilst a bright yellow colour is given by P-naphthol or a mixture containing 1 per cent. of that substance. C. A. M. Analysis of a Sample of Bear-Grease. P. N. Raikow. (Client. Zed., xxviii., 272.)-The following table represents the values obtained in the analysis of fat from a bear killed in the neighbourhood of Sofia. The chief food of the animal had probably been hazel-nuts ; when killed, it appeared to have been asleep for more than one month : Belly.Kidneye. I I ... ... ... ... ... 2 5 O 15' Specific gravity ,? ... ... ... ... ... 15" 15' _- Melting-point of insoluble acids ... ... ... ... Acid value ... ... ... ... ... ... ... Ester value ... ... ... ... ... ... ... Iodine value ... Reichert-Meissl value ... ... ... ... ... Refractometer value i ... ... ... ... ... ... ... ... ... ... ? ? $ 1 ... ... ... ... ... 0.9104 0.9209 32-32 1" 2.2 192.6 98.5 61.2 at 25" 61.2 ,, 1-66 - 0.9211 ' 198.1-198.3 I 1.15 I 53.0 at 40° : 53.0 ,, 107 -4- 106 '5 In appearance the fat resembles lard. I t is pure white in colour, not quite solid even at'Oo C., and only slightly soluble in alcohol. A. G. L. Determination of Betaine by means of a Solution of Iodine in Potassium Iodide.V. Stanek. (li'ozprcicy Eeskk akad., 1904, 12, 36 ; through C'ltenL. Zeit. Rep., 1904, xxviii., 79.)-An aqueous solution of a betaine salt is precipitated by a solution of iodine in potassium iodide. The free base gives no precipitate with this reagent, but does so 8s soon as the solution is acidified. The precipitate is at first brownish-red in colour, but Boon changes to greenish crystals, which melt at 58-61" C. with liberation of iodine. They are practically insoluble in cold water. The author employs a solution of 100 grammes of potassium iodide and 153 gramrnes of iodine in 200 C.C.THE ANALYST. 165 of water. Sodium chloride and sulphuric acid both decrease the solubility of the betaine periodide, but an excess of the reagent is prejudicial.The experiments described in the origind paper show that betaine can be separated from glycocol, asparagine, tyrosine, glutamic acid, and ammonium salt8 by the above method. Acetic acid and lactic acid have no action on the precipitate, but the presence of urea, peptones, and purin bases appears to be unfavourable. w. P. s. The Hydrolysis and Synthesis of Fats by Platinum Black. H. Neilson. ('4iner. Journ. Phpsiol., x., 191-200.)-The author's experiments have proved that platinum black is capable of effecting the hydrolysis of ethyl butyrate in a similar manner to lipase. Thus, when 5 C.C. of a mixture of 200 C.C. of water, 10.4 C.C. of ethyl butyrate, and 2 C.C. of 1 per cent. thymol (as antiseptic) were mixed with 300 rnilligrammes of purified platinum black and kept at 38" to 40" C.with occasional shaking, the following amounts of hydrolysis, as measured by the free acid, were found : After 24 hours, 10.3 ; 48 hours, 28.3 ; '72 hours, 37.3 ; 96 hours, 49.0; and 144 hours, 68.0 per cent. The amount of hydrolysis increased with the proportion of plntinurn added, but not in direct ratio; on the other hand, the catalytic action was found to be independent of the concentration of the ethyl butyrate. The o p t i i t ~ w ~ ~ temperature for the action of the platinum black was about 50" C. The action of most substances poisonous to lipase was to restrict the influence of platinum to a similar extent. Sodium fluoride, however, which is very destructive to lipase, had a much less pronounced action on platinum black.On the other hand, hydrocyanic acid, which was very injurious to the action of platinum black, has much less effect upon lipase. The author also proved that platinum black was capable of effecting the synthesis of butyric acid and alcohol, but the synthesis was less pronounced than the hydrolysis. I n this respect platinum black also resembles lipase (ANALYST, xxvi., 106). C. A. RZ. Notes on Adamkiewicz's Albuminoid Reaction. Dupouy. ( B / i l Z . SOC. P ~ L o ~ I ~ L . Bordeaux. Ann. dc Chi?,&. (inal., 1904, ix., 107, 108.)-The author has found that the most suitable conditions for this reaction are by adding a mixture of 2 parts of glacial acetic acid with 1 part of sulphuric acid to the albuminoid substance, the violet coloration with green fluorescence being then regularly obtained.A similar coloration is given by a reagent consisting of 1 C.C. of sulphuric acid, 2 C.C. of glacial acetic acid, and 1 drop of formalin. This coloured liquid, however, examined spectroscopically, shows a large band between the red and blue parts of the spectrum, whereas the solution in Adamkiewicz's reaction has a spectrum resembling that of urobilin, with an absorption band between the b and F lines. c. A. M. The Determination of Sulphur in Caoutchouc. W. Each. (Chew. Zci!., xxviii., 200.)-The author recommends the method of Henriques as being very exact, provided suitable precautions are taken to guard against mechanical loss. Carius's166 THE ANALYST. method is not generally applicable, as it fails to bring inorganic sulphur present as barium sulphate, etc., into solution. Pfeiffer’s applioation of Eschka’s method (Chem. Zeit., xxviii., 38) gives good results if the mixture is heated to fusion after the carbon has been completely burnt. In many cases the rapid sodium peroxide method of V. Konck (Zeds. angew. Chem., xvi., 516), which can be carried out in a copper crucible, also gives satisfactory results. A. G. L. Contribution to the Study of Cigarette aad Pipe Smoke. J. Habermann.- (Zeits. physiol. Chew, 1903, XI., 148 ; through Chem. Zeit. Rep., xxviii., 25.)-The author finds that the quantity of nitrogenous bases in cigarette smoke is less than that of nicotine in the cigarette, but that the stumps contain a larger quantity. On the other hand, the amount of nitrogenous bases present in the smoke inhaled from a pipe is greater than the quantity of nicotine in the tobacco, increasing as the length of the pipe is shortened. The inhaled part of the pipe smoke is free from hydrocyanic acid, but cigarette smoke contains a small amount of this substance similar to the value (0.0019 per cent. on the original tobacco) previously found for cigar smoke (cf. AXALYST, xxvii., 322). A. G. L.

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DOI:10.1039/AN9042900161

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166 THE ANALYST. BACTERIOLOGICAL ANALYSIS. Contributions to the Methods of Soil Examination. I. The Determination of the Number of Micro-organisms in Soils. (Zentralbl. Bakteriol., 1903, xi., 251 ; through Chem. Zeit. Rep., xxviii., 26.)-The samples used are weighed out, being transferred to the weighing-bottles in an aseptic oven. One gramme of the sample is shaken with 100 C.C. sterilized sodium chloride solution and some enamel shot in a Wagner machine, any further dilution being always followed by continuous shaking. To obtain trustworthy results, at least ten tests should be carried out on each sample. R. Thiele. A. G. L. Formol as a Means of Studying the Liquefaction of Gelatin0 by Microbes. (Contributions to the Study of LiqueQing Diastases.) A. Mavrojannis. (,"its. Hy&?ZC, 1904, xlv., 108 ; through Chem Zed. Rep., xxviii., 24.)-Form01 affords means of discriminating between the action of different diastases on gelatin, since, according to the products formed, which depend on the nature of the culture, the liquefied gelatin will remain liquid or not. I t appears that the substance formed during the first stages of peptonization, down to gelatose, are rendered solid by formol, those formed during the later stages remaining liquid. A. G. L.

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DOI:10.1039/AN9042900166

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年代:1904

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THE ANALYST. 167 INORGANIC ANALYSIS. The Reduction of Lead &om Lead Oxide in Assaying, and the Advantages of an Oxidizing Slag. (Trans. Amer. Inst. Min. Eng., New York Meet. ; through Chem. Zed. Rep., xxviii., 54.)-In a systematic study the authors found that the action of potassium nitrate and lead oxide on sulphide ores varied largely according to the other ingredients of the slag. Thus, the addition of silica, and borax was found inadmissible, borax especially preventing the oxidation of the ore. In presence of sodium bicarbonate, on the other hand, good results are obtained, agreeing well with those given by the older methods. For the actual assay by this method, 4 assay ton ore, 70 grammes red lead, 15 grammes bicarbonate, and as much saltpetre (ascertained by a preliminary trial) as will give a lead button weighing 20 grammes.The charge is placed in Battersea pots holding 10 to 20 grammes, and run down in a, muffle heated to about 900" C., the fusion requiring 15 to 20 minutes. E. H. Miller, E. J. Hall, and M. J. Falk. A. G. L. Note on a Method of Determining Small Quantities of Mercury. Theodore William Richards and Sidney Kent Singer. (Jozirn. Amer. Chem. SOC., xxvi., 300.) -Mercury can be quantitatively separated from cadmium by immersing in the neutral solution, which preferably contains the metals as nitrates, a coil of copper wire, on which the mercury is deposited. Before being used the copper wire should be cleaned with alkali, k i d , and water successively. After the mercury has been deposited, the coil is washed with water and alcohol, dried over calcium chloride, and weighed.I t is then heated at a temperature a little above 350' C. in a current of hydrogen and re-weighed, the loss in weight being due to the mercury. I n practice it is found best to use two coils for each determination, allowing the first to remain in the liquid until the bulk of the mercury has been deposited, and then inserting the eecond to remove the last traces. For quantities of about 0.03 gramme of mercury the best results appear to be obtained by leaving the first coil four to five hours in the solution, and the second coil twenty hours. The test results given are satis- factory. A. G. L. On a Simple Method for the Determination of Arsenic in Hydrochloric Acid and Sulphuric Acid. (Chem.Zeit., xxviii., 211.)-The method depends on the fact that when potassium iodide is added to sulphuric or hydrochloric acid containing arsenic in either state of oxidation, arsenious iodide is formed, which is insoluble in fairly concentrated acids, but soluble in water. The presence of chlorine, ferrio chloride, or selenium exerts an injurious influence on the reaction, but this may be obviated by adding a few drops of a strong solution of stannous chloride in hydrochloric acid (specific gravity 1.175) just before adding the potassium iodide. To determine arsenic in hydrochloric acid, 50 C.C. of the acid of specific gravity 1.17 to 1.18 are taken; should the acid be weaker, it is brought to this strength by the addition of sulphuric acid (specific gravity 1.45).Five C.C. of N. U. Blattner and. J. Brasseur.168 THE ANALYST. 30 per cent. potassium iodide solution are then gradually added, with constant stirring. After standing for one minute, the liquid is filtered through glass wool or cotton wool, the filtrate being tested for arsenic by adding more potassium iodide. The precipitate is then washed with pure strong hydrochloric acid, to which 10 per cent. of the potassium iodide solution bas been added, after which it is dissolved in water, the solution made alkaline with sodium bicarbonate, and titrated with iodine solution. I n the case of sulphuric acid, 25 C.C. of the acid, which should have a speoific gravity of 1.45, are taken ; to prevent the precipitation of any lead iodide, 25 C.C. of concentrated hydrochloric acid are then added, after which the procedure is the 8ame as for hydrochloric acid, The method is said to give good results with quantities of arsenic up to 0.20 per cent., the values obtained in the case of small amounts being accurate to 0.001 per cent. A.G. L. The Volumetric Determination of Arsenic and Antimony in Nickel Ores. H. Nissenson and A. Mittasch. (Chem. Z e d . , xxviii., 184.)-The method is a modification of Nissenson and Siedler's method (ANALYST, xxviii., 324) applicable to the determination of both arsenic and antimony. I n a 250 C.C. flask, 0.5 gramme of finely powdered ore is heated with 8 C.C. of concentrated sulphuric acid for several hours, until the mass becomes completely white or light-yellow; 50 to 100 C.C. of water are then added, the liquid is boiled until all basic salts are completely dissolved, and, without previous filtration, treated with hydrogen sulphide.The sulphides of arsenic, antimony, and copper obtained are filtered off together with the insoluble residue, washed back into the original flask, and dissolved by heating for several hours with 7 C.C. of concentrated sulphuric acid. The solution, which contains arsenic and antimony in the lower state of oxidation, is then diluted with about 100 C.C. of water, heated to boiling, and titrated with & potassium bromate solution, using 3 drops of indigo solution as indicator ; the indigo is preferably added only just before the end of the titration, if the amount of arsenic and antimony present is known approximately. To the titrated liquid a little more potassium bromate is added; after evapora- tion to a very low bulk it is then treated with tartaric acid, an excem of ammonia, and magnesia mixture to separate the arsenic. After long standing the precipitate is filtered off and washed slightly with ammonia; the filtrate is acidified with sulphuric acid, and freated with hydrogen sulphide, the sulphide precipitate being dissolved and titrated as before, giving the quantity of antimony present.The arsenic is obtained by difference. Results obtained in this way are always slightly high as regards antimony, the arsenic not being quite completely separated as magnesium ammonium arsenate. To eliminate this error a constant correction may be applied to the results; or the sulphide precipitate obtained after the removal of the arsenic may be extracted with ammonium carbonate to remove the last traces of arsenic ; or else another portion of the ore may be dissolved in brominated hydrochloric acid, which volatilizes the arsenic, and the antimony determined in the solution, either by electrolysis or by titration with bromate, after reduction with sodium sulphi te.A. G. L.THE ANALYST. 169 The Colorimetric Determination of Chromium. A. Moulin. (Bidl. SOC. Chim., 1904, xxxi., 295-296.)-This process is based.on the fa&t recorded by Cazeneuve that the acetate of diphenylcarbazide gives a purple coloration with chromic acid and chromates. The reagent is prepared by dissolving 2 grammes of diphenylcarbazide in a mixture of 100 C.C. of 90 per cent. alcohol and 10 C.C.of acetic acid on the water- bath, and diluting the solution to 200 C.C. with alcohol of the same strength. The standard solutions of chromic acid used for the colorimetric comparison contain 0.50 gramme or 0.05 gramme in a litre. I n the determination, from 0.25 to 0.5 gramme of the sample is dissolved, chromium salts being converted into chromates in the usual way. I n the case of chrome iron the solution is oxidized by boiling with hydrogen peroxide in the presence of an excess of potassium hydroxide, the precipitated metals separated by filtration, and the filtrate and washings neutralized with acetic acid and diluted to 100 or 200 C.C. Portions of 1, 1.5, 2 c.c., etc., of the standard chromic acid solution are then introduced into a series of test-tubes, each of which contains 2 C.C.of the reagent and about 70 C.C. of water, whilst corresponding quantities of the solution under examination are introduced into a similar series of tubes. The liquids are diluted to 100 c.c., allowed to stand for twenty minutes, and the colours matched. The author states that this method yields very exact results, but that it is essential to have an excess of diphenylcarbazide. C. A. M. The Precipitation of Magnesium Oxalate with Calcium Oxalate. Nicholas Knight. (Chenb. News, lxxxix., 146.)-From analyses of dolomite made by different students the author comes to the conclusion that the magnesium precipitated with the calcium varies from an inappreciable amount (0.18 per cent. MgO) to a con- siderable quantity (1.20 per cent.MgO). He therefore recommends always to dissolve the unwatlhed precipitate of calcium and magnesium oxalates in hydrochloric acid, and reprecipitate the calcium with ammonia. A. G. L. The Use of Organic Magnesium Compounds in Analytical Operations. L. A. Tchongaeff. (Joiiru. SOC. Phys. CILim. B., xxxiv., 652 ; through Chem. News, Ixxxix., 139.)-Organic magnesium compounds of the type RMgI, where R represents an organic radical-e.g., CH,-are decomposed by water according to the equation : With organic compounds containing the hydroxyl group they react similarly. The author has consequently used the methyl derivative CH,MgI both for the recognition of the hydroxyl group, CH, being evolved, and as a means of separating bodies con- taining hydroxyl-e.g., alcohols, from other volatile substances--e.g., hydrocarbons.I n the last case, the alcohol is treated with an ethereal solution of CH,MgI, when it is converted into a non-volatile compound of the type ROMgI, whilst the hydrocarbon is not changed, and can be separated by distillation. RhlgI + H,O = R E + MgIOH. A. G. L.170 THE ANALYST. Some Applications of the Theory of Eleotrolysis to tbe Sepazation of Hetale from one another. (Chem. News, lxxxix., 110, 125.)-The author proposes to overcome the difficulties met with in the electrolytic separation and deposition of metals having higher polarization potentials than hydrogen (1) by reducing the resistance of the bath by the suppression of the formation of gae at the anode ; (2) by using cathodes of other metals besides platinum ; and (3) by forming complex salts.The first principle can be carried out in two ways : either by adding a reducing agent to the bath, or else by using a, soluble anode. For example, nickel can be separated from zinc in a solution containing ammonium sulphate and magnesium sulphate, to which sulphurous acid and an excess of ammonia is added; the operation is carried out at 90° C. Nickel can also be separated from zinc by using a zinc anode placed in a solution of magnesium sulphate, which is separated by a porous mem- brane from the solution containing the nickel and zinc, to which a large excess of ammonium sulphate and ammonia is added. A platinum cathode is placed in this liquid and connected by a metallic conductor with the zinc anode, no extraneous current being necessary.The solution should be heated nearly to boiling during the electrolysis. The polarization potential of metals which, using a platinum cathode, have a higher potential than hydrogen, can also be lowered below that of hydrogen by choosing a suitable metal for the cathode ; but in this case it must be remembered that as soon as the metal to be deposited covers the cathode, the latter behaves as though it consisted of this metal, so that the precipitated metal itself must possess the property of raising the polarization potential of hydrogen to the necessary degree. In this way lead, tin, and cadmium may be deposited from acid solutions, and cadmium may be separated from zinc, also in acid solution, by using a platinum cathode previously coated with tin or cadmium.The formation of complex ssllts has been already studied by Freudenberg (Zed. P'hys. Cliem., xiii., 97). The separation of tin and antimony in a solution contain- ing sodium hydrogen aulphide is an example, the tin passing into the state of a complex ion. Practically all the above methods are only approximstely quantitative, and require further working out. A. Hollard. A. G. L. The Direct Determination of Potassium in the Ash of Plants. Edward Murray East. (Joum. Anter. Chew. SOC., xxvi., 297.)-The ash from 2 or 3 grammes is prepared by moistening the sample with a 20 per cent. ammonium nitrate solution, drying, and incinerating for two hours at a temperature just below a red heat. The ash is transferred to a beaker with a few drops of hydrochloric aoid, the solution is heated to boiling, and 3 to 5 C.C.of barium hydrate solution, saturated at 32" C., are added. After one hour's digestion, the liquid is filtered hot, hot water also being used for the washing. The barium is next precipitated as sulphate by means of a iodhrn sulphate solution equivalent to the barium hydrate solution used. After five hours the liquid is filtered, and the filtrate evaporated down to 25 C.C. in a platinum dish. A drop or two of hydrochloric acid and the calculated amount ofTHE ANALYST. 171 platinic chloride necessary to convert all the alkalies into the chloroplatinates are added, and the determination is completed as in the Lindo-Gladding method. The method gives cloeely agreeing results, and requires much less time than the older methods.A. G. L. A Study Silberberger. sulphuric acid of the Quantitative Determination of Sulphuric Acid. Richard (Mowtshefte f. c'Jiei)i., xxv., 220.)-The author finds that when - - is precipitated in the presence of ferric salts with barium chloride, a, part remains in solution as a complex ferric-sulphuric acid, whilst some of the iron is thrown down in the form of the salt Ba,Fe,(SOJ6. If potassium nitrate is present in the solution during precipitation, the barium sulphate is contaminated by the double salt KBa,(NO,)(SO,), ; in the presence of potassium chloride the' salt KBa,Cl(SO,), is formed. In any case, barium sulphate is quite appreciably soluble in acid liquids, so that, if the precipitate obtained as usual is purified by treatment with hydrochloric acid after ignition, the results obtained are always too low unless the barium sulphate dissolved in the original filtrate is recovered by evaporation. On the other hand, when sulphuric acid is precipitated by means of an alcoholic 10 per cent. solution of strontium chloride, a volume of alcohol equal to twice the volume of the original liquid being then added, strontium sulphate is precipitated quantitatively in a pure condition. The author therefore proposes to use this method of determining sulphuric acid, especially for the andysis of pyrites and other metallic compounds, such as chromium and zinc salts. .4. G. L.

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DOI:10.1039/AN9042900167

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年代:1904

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THE ANALYST. 171 APPARATUS. Apparatus for taking Samples of Water Some Depth below the Surface. A. Bujard. (Zeit. f iir Uiitersitch. der *Yahr. itntl Geiiitssmittel, 190.1, vii., 221, 222.)-The apparatus is shown in the accom- panying illustration. A brass frame is clamped to a long wooden rod by means of thumb-screws. At the lower part of the frame is a hinged clamp, in which the bottle is secured, whilst the neck of the bottle is held in the collar screwed down from the upper part of the frame. A cord attached to the eyelet serves to open the stopper, and on releasing the tension on the cord the stopper is forced into place by a spring. The apparatus may be used for taking samples of water either for bacteriological or chemical analysis. I n the latter cam, the size of the frame may be in- (This apparatus is very similar to the one exhibited by creased to acconimodate a larger bottle. w. P. s. Mr. W. Chattaway at a meeting of the Society some time since.)

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DOI:10.1039/AN9042900171

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年代:1904

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