摘要:

DECEMBER, 1908. Vol. XXXIII. NO. 383. THE ANALYST. PROCEEDINGS OF THE SOCIETY OF PUBLIC ANALYSTS AND OTHER ANALYTICAL CHEMISTS. THE ordinary monthly meeting of the Society was held on Wednesday evening, November 4, in the Chemical Society’s Rooms, Burlington House. Tn the absence of the President, the chair was occupied by Mr. John White, F.I.C., Vice-president. The minutes of the previous ordinary meeting were read and confirmed. The CHAIRMAN said that at the meeting of the Council that afternoon a vote of condolence with the family of the late Sir Thomas Stevenson had been passed, and would be duly forwarded to them. Certificates of proposal for election to membership in favour of Messrs. P. Murphy, A.I.C., and W. Rintoul, F.I.C., were read for the second time; and certificates in favour of Messrs.Frederick J. Bolt, F.I.C., 2, City Road, E.C., metallurgical, analytical, and consulting chemist ; Leonard Clement, A.I.C., Beamsley, Fairhaven, near Lytham, Lancs, analytical chemist ; Samuel H. Davies, M.Sc. (Vict.), chemist to Messrs. Rowntree and Co., Ltd., York; Arthur George Harrington, A.I. C., Rochford, Westbury Road, Ealing, W., Municipal Analyst for Singapore ; Ernest John Parry, B.Sc. (Lond.), F.I.C., 568, Great Dover Street, S.E., analytical chemist ; Narcus Edward Rudolf, 33, Elgin Avenue, Maida Vale, W., and c/o Straits Trading Company, Singapore, analytical chemist ; and Robert Low Smith, 56, Genesta Road, Plumstead, S.E., chemist to Messrs. Johnson and Phillips, Ltd., Charlton, S.E., were read for the first time, Messrs. E.H. Croghan and R. Glegg, B.Sc., F.I.C., were elected members of the Society. The following papers were read : The Solvent Action of Carbonic Acid on the Carbonates of the Heavy Metals,” by Clarence A. Seyler, B.Sc., F.I.C. ; “The Estimation of Cocoanut Oil in Butter,’’ by Raymond Ross, F.I.C. ; ‘‘ The Analysis of Camphorated Oil for Camphor Substitutes,” by F. W. Richardson, F.I.C., and William K. Walton ; and I ‘ The Separation and Estimation of Certain Volatile Fatty Aaids by Extraction with Benzene or Toluene,” by T. R. Hodgson, B.B. The CHAIRMAN said that he had been asked by the Council to draw the attention of members to the Analytical Investigation Scheme, which appeared to be very successful. Ten investigations bearing on problems connected with analytical chemistry were in hand, and the Council would welcome suggestions as to suitable subjects for reference. It was requested that any such suggestions be communicated to one or other of the Hon. Secretaries.

ISSN:0003-2654    

DOI:10.1039/AN9083300449

出版商:RSC    

年代:1908

数据来源: RSC

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450 THE ANALYST. THE DETECTION OF POISONOUS BY G. D. LANDER, D.Sc., F.I.C., AND H. METALS. W. WINTER. (Read at the Meeting, June 3, 1908.) THE object of this paper is to suggest methods for a rapid and simple qualitative search for poisonous metals. I t is an advantage to limit the manipulatory opera- tions as far as possible, rather than to test separate samples for special substances; and it is also most important to avoid the use of large quantities of reagents, involving risk of the introduction of adventitious impurities, and to be able to conveniently deal, if necessary, with quantities of organic matter as large as 4 or even 8 ounces. For a preliminary analysis we therefore adopt the following two processes : 1. A Reinsch test for arsenic, antimony, bismutb, and mercury.2. Extraction (without destruction of organic matter) by means of 50 per cent. nitric acid and a small proportion of sulphuric acid of lead, mercury, bismuth, copper, zinc, and chromium. By omitting the sulphuric acid, barium may also be here included. As regards the Reinsch test, little need be said at present. We do not, naturally, claim for it the mathematical precision of the many excellent methods recently elaborated for the estimation of arsenic. It may, however, be well to- mention a few of its advantages. I t gives evidence of mercury, antimony, and bismuth, as well as of arsenic. I t is a concentration method, permitting one t o handle comparatively large amounts of substance in a reasonably short time, and thus enabling the analyst to obtain a sufficient amount of the poisonous metal to allow of its detection with added certainty. When seeking for traces, the material may be left to boil under a reflux condenser as long as desired.We consider the accuracy to be ample, having in numerous test experiments, which needl not be described here, satisfied ourselves that 0.05 mgm. of arsenic may be- recognised with absolute accuracy when added to as much as 8 ounces of visceral contents. With antimony satisfactory evidence is yielded by 0.1 mgm., but with mercury we find that really satisfactory evidence is not to be got with less than 1 mgm. in 4 ounces. Having obtained a deposit on copper, the analyst has at his disposal numerous methods for further examination. We may, however, mention here that we find solution in pure sodium peroxide and a Marsh test the most suitable method for arsenic.We are, moreover, of the opinion that very little time is saved by a direct ‘‘ Marshing ” of the crude material. Although this latter process can be worked well with small quantities of material, we have not made any attempt to apply it to quantities of several ounces of substance having the varied characters of visceral ingest a. In our second process nitric acid may be used alone, but we find that the addition of a small proportion of sulphuric acid improves the extraction of any metals that may be present. Exact data as to proportions are quoted in the tabularTHE ANALYST. 451 comparison at the end of this paper. In general, we cover the material to be tested with 50 per cent.nitric acid, and add from 5 to 10 C.C. of concentrated sulphuric acid. The mixture is heated over a small flame in a dish to a pasty consistency, and the operation stopped when dense brown fumes are evolved- usually in less than twenty minutes. The residue is then suitably diluted and filtered. At this point lead may be sought for by means of sulphuric acid and alcohol ; but, since calcium sulphate is often deposited, we consider it more reliable and quicker to detect lead in the following manner : The filtrate is rendered strongly alkaline with ammonia, and a slight excess of ammonium sulphide added. This preoipitates phosphates, chromium hydroxide, and sulphidea of iron, lead, mercury, copper, bismuth, and zinc, and on filtration and washing these are obtained practically free from organic matter.I n this respect, and also in the certainty of precipitation, ammonium sulphide presents great advantages over the use of sulphuretted hydrogen in acid solution, where, as is well known, copious precipitates of organic matter are always obtained-for instance, in Autenriet h’s process. In examining the precipitate we extract with dilute hydrochloric acid, which leaves copper and mercury. In this solution lead is searched for by sulphuretted hydrogen (which also, of course, precipi- tates bismuth), and confirmed as sulphate, and zinc is tested for after removal of ead, bismuth and iron, by ammonium sulphide. We do not find that it is necessary to carry out a phosphate separation before looking for zinc. Copper is extracted by nitric acid and confirmed with ammonia or ferrocyanide, and mercury is taken up with hydrochloric acid and potassium chlorate, and after evaporation tested for with stannous chloride. By means of these two processes, from 4 to 8 ounces of material can be tested for all the metals named in from two to three hours with a minimum expenditure of reagents.The only method which appears to us a t all capable of equally general application is that of destruction of organic matter by means of concentrated sulphuric acid, and we have therefore made a number of comparative tests, bearing on delicacy, expenditure of material, time involved, and bulk of solutions to be handled. We selected ground linseed cake as the experimental material, since it is homogeneous and contains more carbon than visceral contents; but as regards destruction by sulphuric acid, we think most analysts will share our opinion that 4 ounces of material is an excessive quantity with which to undertake this operation.We have tried large amounts, but in practice limit the quantity to not more than 50 grams. Potassium sulphate, ammonium persulphate, and nitric acid have been used to facilitate the action, pure sulphuric acid being very much slower. The quantities of added metal have been reduced to amounts considerably short of what is likely to occur in practice, and me can only, therefore, make rough statements as to the qualitative evidence obtained. In every case there was added to the mixture 0.1 mgm. of lead, 0.2 mgm. of mercury, 0.6 mgm. of copper, and 1 mgm.of zinc. The experimental material in cases 1 to 9 was powdered linseed cake, in 10 and 11 the stomach contents of a dog. We think our results prove that the process of extraction with 50 per cent. nitric acid and a small proportion of sulphuric acid compares favourably with the452 THE ANALYST. destruction of organio matter in respect to time, delicacy, and expenditure of material. Ammonium persulphate is the best accelerator. Material. (1) 10 grams (2) 50 g r a m (3) 10 grams (4) 50 g r a m (5) 10 grams (6) 10 grams (7) 10 grams (8) 60 grailis (9) 10 g:.ams (10) 15 graiiis (11) 15grams Reagent. 50 C . C . H,SO, 20 grs. K,SO, 300 C.C. H2S04 100 grs. K2S04 60 C.C. H2S0, 6 grs. 300 C.C. H,S6, “H4)2S*O 85 grs. 60 C.C. H,SO, (3 H,),S,O* 13 C.C. conc.HXO:, added gradually 40 C.C. HNO,] 5 C . C . H,SO, 40 C.C. HNO, 5 C.C. H,SO, 150 C.C. HNO, 10 C.C. H,SO, 40 C.C. HNO,, 2 grs. (KHJ)2SP0 50 C . C . H,S8, ‘LO grs. K2S0, 40 C.C. HNO,, 5 C.C. H,SO, Time of Heating. 6.45 Iirs. 6’45 hrs. 4 hrs. 7-25 hrs. 1 hr. 30 mins. 20 mins. 45 mins. 20 mins. 3.5 hrs. 20 mins. VOl. of Fil. trate (Am- moniacal). 250 C.C. 850 C.C. 250 C.C. 825 C.C. 200 C.C. 200 C.C. 125 C.C. 250 C.C. 100 C.V. 225 C.C. 250 C.C. Lead. Present Present Present Present Present Prescn t Present Present Present Present Present Mercury. Doubtful Absent Doubtful Doubtful Absent Present Doubtful Present 1)oubtful noubt ful I>oubtful Copper. Present Present Present Present Not tested Present Present Present Absent Presmt Present Zinc. Present Present Present Present Prescil t Absent Present Present Do tibt fu 1 Absent Present I t may be of interest to mention the range of quantities actually found in the investigation of numerous cases of poisoning among animals.Reduced to milligrams per ounce they are : Arsenic ... ... ... ... . . . . . . 5 to 0.3 Lead ... ... ... ... ... ... 140 to 15 Mercury .. ... ... ... ... . . . 72 to 1.1 DISCUSSION. The CHAIRMAN (Mr. Fairley) asked whether in the Reinsch test the authors had any preference for copper gauze to foil. Some of the new remedies contained organic arsenic compounds-atoxyl, for instance-by means of which it was claimed that larger amounts of arsenic could be taken than in any other form. He did not quite see how such organic compounds would be dealt with in the authors’ scheme, and he thought it would be necessary to first break up the organic combination.If the process suggested by the authors were relied on for the detection of mercury in a dilute nitric acid solution, it must be borne in mind that if there were present any sulphur compounds capable of producing mercuric sulphide, this was one of the most stable of the sulphides in the presence of nitric acid, and might not be decomposed.THE ANALYST. 453 But that, of course, only partially applied, because evidence ELS to the presence or absence of mercury would be afforded by the Reinsch test. Mr. F. W. RICHARDSON asked how the authors’ procedure would apply in the case of beer. As far as the detection of arsenic in beer or in human remains was concerned, he could not altogether accept the authors’ suggestions.Some years ago (Jounz. SOC. Chem. Ind., 1902, 21, 901) he had recommended oxidation of the organic matter with nitric acid and sulphuric acid in a flask, the flask being connected with a Woulffe’s bottle containing a considerable quantity of water, into which the nitric and nitrous acid gases were drawn and absorbed. By that method, which he still used constantly, human remains could be readily oxidised, and beer completely. Then, by the Gutzeit test, as little as i&c mgm. of arsenic could be de- tected in 70 C.C. of liquid, and st the end of the experiment a purely mineral solution was obtained which could be used for the ordinary processes of examination for other metals. His experience of the Reinsch test, which he had tried several years ago, was that it was of very little use for the detection of minute quantities of arsenic.Mr. CHAPMAN, referring to Mr. Richardson’s remarks, said that in testing for arsenic it was quite unnecessary to destroy the organic matter save in a very few cases, seeing that perfectly accurate results could be obtained by introducing the organic solution directly into the generation flasks. His own experience in this direction had been very considerable, and had been amply confirmed by the experience of many of his colleagues. He agreed with Mr. Richardson that the Gutzeit test was capable of detecting with certainty minute quantities of arsenic, but, whilst it was rapid and convenient, it possessed several serious disadvantages as compared with the Marsh-Beraelius process.E e should have thought, however, that the detection of exceedingly minute quantities of arsenic was rather outside the subject-matter of the present paper. For the destruction of organic matter prior to an examination for poisonous metal, he (Illr. Chapman) had often found it a great advantage to oxidise with strong sulphuric acid in a manner similar to that observed in the ordinary Kjeldahl method. In this way, mercury and other metals which were volatilised on ignition could easily be obtained in a condition suitable for the application of the ordinary analytical procedure. He .(Mr. Chapman) had had a great deal of experience of the Reinsch test, and could confirm the author’s observa- tion that positive results could be obtained with arsenic acid, but this was probably due to the fact that the hydrochloric acid in the presence of organic matter reduced the arsenic acid to the arsenious condition. Mr.P. A. E. RICHARDS said that the sulphuric acid process mentioned by Mr. Chapman was, in his experience, a very good one. With regard to the detection of tin in stomach contents, etc., if a small piece of zinc were placed in the slightly acid fluid a deposit of tin would be obtained on it which could be easily and speedily dissolved by boiling with strong hydrochloric acid. The usual tests could then be applied to this solution. Dr. LANDER, in reply, said that he should object on practical grounds to what he might call the LLmatliematical” detection of a metal-like arsenic, which, from a purely practical standpoint, was not a desideratum. Personally he preferred foil to454 THE ANALYST. gauze in the Reinsch test, because on a small surface the deposit was more concen- trated. He had had no direct experience with atoxyl, but thought it probable that it would be decomposed by boiling hydrochloric acid of the strength used. But since rttoxyl was not a poison, it would perhaps be an advantage if it did not give a deposit on copper. He was obliged to the Chairman for his suggestion as to the possibility of mercury being overlooked through non-decomposition of the sulphide. It was certainly important to bear this in mind. He agreed that the method of oxidation with sulphuric acid and nitric acid was excellent for the complete destruction of organic matter, hut in looking for small quantities of lead, copper, zinc, and SO OD, large quantities of material must be operated upon, and this tedious destruction was what they had tried to avoid, They had tried some of the electrolytic methods, but had not obtained particularly good results with them. Tin, as had been mentioned, was not included in their scheme, but he agreed with Mr. Richards that in quantities likely to be dangerous it would be readily detected by deposition on zinc.

ISSN:0003-2654    

DOI:10.1039/AN9083300450

出版商:RSC    

年代:1908

数据来源: RSC

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454 THE ANALYST. THE SOLVENT ACTlON OF CARBONIC ACID UPON THE CARBONATES OF HEAVY METALS. BY C. A. SEYLER, B.Sc., F.I.C. (Read at the Meeting, November 4, 1908.) E. F. FREE (Journ. Amer. Chem. Soc., 1908, 30, 1366) has shown that the basic carbonate obtained by precipitation of cupric salts with sodium carbonate, when left in contact with water containing carbonic acid, attains a constant composition and solubility similar to natural malachite, CuCO,.Cu(OH),, except in the degree of hydration. The solubility was found to increase with the concentration of the free carbonic acid, but no law was deduced. For some time past I have been engaged upon an investigation of the solubility of calcium and magnesium carbonates in conjunction with Mr. P. V. Lloyd, the results of which will shortly be published.In consequence of the experience thus gained, it occurred to me to see whether Free's remlts exhibited any regularities similar to those found for 'the other carbondes, and whether these could not be deduced from the principles of chemical equilibrium. Assuming that the solid ground substance is CuCO,.Cu(OH),, and that the copper exists in solution as bicarbonate, the reaction would be- or, since the bicarbonate must be split into copper and HCO, ions- CuCO,Cu(OH), + 3H,C03 = ~ C U + 4HC0, + 2H,O. The active mass of the solid carbonate and of the water being constant, we shall CUCO,.CU( OH), + 3H,C03 = 2Cu(HCO3), + 2H,O ; have the cmdition of equilibrium as follows : cu2 Hcos(= k , where k is a constant H,co33 and the other symbols stand for ionic concentrations.THE ANALYST, 455 If po other copper salt or bicarbonate be present, the whole of the copper in solution will practically exist as bicarbonate, and the concentration of the copper ions will always be half that of the HCO, ions, or Cu=$ HCO,.Hence for this case we have- I n other words, the square of the dissolved copper ions should be proportional to the free carbonic acid. I n Free’s experiments the concentration of the copper must be multiplied by the degree of ionisation of the copper bicarbonate, which may be taken as equal to that of copper chloride a t the same concentration. These figures not being to hand, I have assumed the same degree of ionisation as copper sulphate. Further, the free carbonic acid has been deduced from the total on the assumption that the copper existed as basic carbonate, and must therefore be corrected on the basis of bicarbonate, The results are expressed in mgms. per litre.The correction is not large, but I have made it. Copper. 1.5 8.3 13.7 17.0 25.7 28-0 31.0 33.7 34.8 35.3 39.7 Ionisation. 0.94 0.93 0.92 0.91 0.90 0.89 0.88 0.87 0-86 0.85 Ions. - 7-80 12.74 15.64 23.38 25.20 27.59 29.65 30.28 30.35 33.75 H,CO,,. - 149 263 330 716 830 929 1,123 1,187 1,231 1,508 Cu2/H,C0,. - 0.408 0.617 0.741 0.763 0.765 0.819 0.783 0,772 0.748 0.755 I n the first experiment the carbonic acid cannot be zero, but will be determined by the hydrolysis of the carbonate. This also affects the next two figures, but after this the value of Cu2/H,C03 shows satisfactory constancy.The law above deduced therefore holds good between wide limits. Free’s experiments also show that calcium sulphate and small amouiits of sodium chloride do not much affect the solubility, but that large amounts slightly increase it. Salts, however, which yield either the copper or HCO, ion should depress the solubility ; accordingly, we find that sodium bicarbonate greatly diminishes the solvent action. It is of interest to see if Free’s results follow the law deducible from the equilibrium, which is the same that we have found experimentally to hold good for calcium carbonate. Since cu2xHc~34 = k , it follows that when the free carbonic acid is kept, the H2c03 same the value of Cu2xHCOQ4 will be constant, or, what is the same thing, JCi x HCO, should be constant.The square root of the dissolved copper should456 THE ANALYST, Copper. 35 27 10 be proportionate to the total bicarbonate ions. We may express the bicarbonate ions in terms of their equivalent in copper, remembering that the results must be multiplied by two, since there are always two ions of HCO, for each one of copper. The value of the constant for H,CO, = 1,200 works out to 325. I have applied these considerations to the figures given by Free. Cu equiva NaHCO,,. Ionisation. =Ions. a. leiit to 0.86 30.1 5.486 - 0.90 24.3 4.930 5.94 0.94 9.4 3.067 59.44 EFFECT OF SODIUM BICARBORATE. 60.2 59-88 125.80 330 295 385 I - - 60.2 0.95 5.98 57-56 0.90 56.70 126.55 1onisatioii.J = ~ o n u . 338 274 321 I 35 0.86 30.1 5.486 25 0.91 22.75 4.77 7 0-94 6-58 2.536 I - - - 6-30 63.00 0.95 5.64 0.90 1 53.50 EFFECT OF CALCIUM BICARBONATE.I I I I I have neglected the cases in which the copper is reduced to ab.out 1 mgm., since the solubility is then not greater than that in pure water. Considering the fact that free carbonic acid was only approximately the same, and that the ionisation factors are uncertain, I think that the constancy of the product is good enough to show that the law deduced holds good. These results lead one to expect that similar regularities will be found for the carbonates of other heavy metals. I t has been shown by Mikusch (Zeit. aizorg. Chem., 1907, 56, 365) that, except ZnCO, (corresponding to calamine), the only other carbonate of zinc is 2ZnC0,.3Zn(OH),.H20, corresponding to the mineral hydroxincite.I have recently examined a deposit which was formed in a spring water containing free carbonic acid, where it was heated by proximity to a boiler after passing through galvanised iron pipes. The pipe was almost completely blocked by the deposit, which had exactly the composition of hydrozincite. Assuming that this is the ground substance, and that the reaction is 2ZnC03.3Zn(OH), + 8H,C03= 5Zn(HCO,),+ 6H,O, the equilibrium would be governed by the condition Znl5 x H,CO,S = k, or Zn1.S75 = kH2C0, This would not be very different from Zn2 = kH2C03. Similarly, since it has been shown by Hawley (Journ. Phys. Cheva., 1906,10, 654) that the only basic lead carbonate is 2PbCO,.Pb(OH),, we should have the law Pb9 = IcH2C0,4, or Pb2.2 = IcH,C03, again approximating to the same law. In all three cases the effect of bicarbonate would be to diminish the solubility according to the law J B - x HCO,=constant, when the carbonic acid is kept constant. This explains the fact of the protective action of calcium in solution as bicarbonate upon waters which act upon lead and zinc. Evidently the solvent action will be a function of both the free carbonic acid and the total bicarbonates.THE ANALYST. 457 When the hydrolysis of these carbonates has been properly investigated, we shall probably be on the way to a satisfactory explanation of the action of natural waters upon lead and zinc.

ISSN:0003-2654    

DOI:10.1039/AN9083300454

出版商:RSC    

年代:1908

数据来源: RSC

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THE ANALYST. 457 THE ESTIMATION OF COCOANUT OIL IN BUTTER. BY RAYMOND ROSS, F.I.C. (Read at the Jfeeting, November 4, 1908.) I: Tlic title of this palm is perhaps somewhat niisleuding, for, dtliongli the investigatioii w i ~ s originally undertaken with a view to the cstiniation of cocoanut oil, the net result is only to throw some light on the coniposition of certain butters and cocoanut oils. I triist, Iiowever, these results may not be without interest.] E. HINKS (ANALYST, 1907, 32, 60) has described a method for the determination of cocoanut oil in butter based on the microscopical examination of the soluble residue obtained by freezing out the fat from ether and alcohol. I t appeared to me that this process might be made quantitative, and the proportion of cocoanut oil estimated by a determination of the constants of the residue.I t is generally admitted that cocoanut oil is much more soluble than butter-fat, and a sample that I obtained did not freeze out at all under the conditions to be indicated later, nor did the fatty acids of this oil when similarly treated. This led me to think -that practically the whole of the cocoanut oil might be concentrated into a filtrate, and that many of the substances contained in butter would be removed. Experiments with pure fatty acids further showed that oleic, myristic, and lauric acids were all easily soluble even at fairly low temperatures, while stearic and palmitic acids are less so, their solubility decreasing rapidly with the lowering of temperature. The above remarks also apply to alcoholic solutions of these scids.As the question of volatile fatty acids has been practically dealt with in the investigations of the Polenske method, I decided to confine my efforts to the in- soluble fatty acids, which, of course, constitute by far the larger proportion of the fats under consideration. After various experiments the method adopted was as follows : Four grams of the fatty acids were dissolved in 20 C.C. of ether, and cooled in a, freezing mixture of salt and ice to -15" C. The frozen-out portion was then stirred, with the addition of 10 C.C. of ether, at a temperature of - 15" C. and rapidly filtered. The ether was evaporated from the filtrate, and the residue so obtained treated with alcohol in an exactly similar manner. The alcohol mas removed by evapora- tion on the water-bath, and the Zeiss butyro-refractometer reading of the residue recorded.Experiments on these lines on butters adulterated with cocoanut oil (later referred to as original sample) gave satisfactory results. A butter of known origin and six samples received under the Food and Drugs Acts were used for the purpose of obtaining constants. Later, Mr. Bevan kindly sent me four test samples B, G, C, 0) containing unknown quantities of cocoanut oil.458 THE ANALYST. The following results were obtained : Sample. Residue. Per Cent. Farm butter ... ... Average of six samples ... Cocoanut oil ... ... H ... ... ... ... G ... ... ... ... c ... ... ... ... 0 ... ... ... ... - - 100 64.1 55.1 56.2 54% Zeiss Refractometer reading 45" C.33.0' 33.0'k 1.5 14.5" 27.5. 29.5" 31.0' 32.0. Cocoanut Oil. Calculated. Per Cent. Added. Per Cent. - - 100 20.0 10.0 6.0 3-0 The method of calculation was based on the assumption that the whole of the cocoanut oil was present in the filtrate, and that 33.0 and 14.5 respectively were the refractometer readings for the residues from pure butter and cocoanut oil fatty acids. The process having proved so far satisfactory, it was desirable to test it further with foreign butters of known origin. The following samples were examined in a similar manner : Sample. Residue. Per Cent. Finnish ... ... ... ... Argentine ... ... ... ... Danish ... ... ... ... Siberian ... ... ... ... Swedish ... ... ... Irish salt ... ... ... ... 61 69 57 62 52 40 Zeiss Refractometer Reading 45" c.26" '28" 31" 27" 3 3" 34" Iodine Absorption. 30.0 32-4 39.0 30.0 45.6 47.8 Oleic Acid calculated per Cent. 33.3 36.0 43.3 33 *3 50.6 53.1 From these results it is evident that the process completely breaks down, but it was thought that some relationship might exist if the refractions due to unsaturated fatty acids (calculated as oleic acid from the iodine value) were allowed for. For this purpose the iodine values of the residues given in the first table were determined : Iodine Oleic Acid. Value. Per Cent. Sample. English farm ... ... ... 48-0 ... 53-3 Cocoanut oil ... ... ... 8.0 ... 8.9 H ... ... ... ... ... 36.4 ... 40.4 G ... ... ... ... ... 39.6 ... 44.0 c ... ... ... ... ... 44.4 ... 49.3 0 ... ... ... ... ... 47.1 ... 52.3 The refractometer reading for oleic acid at 45' C.was found to be 41.5, or Some of the readings were calculated into the refractive indices, and Nd 1.4534.THE ANALYST. 459 the amount due to unsaturated acids deducted, and the refraction of the saturated acids thus obtained : Sample Refractive Index Fatty Acids. less Oleic Acid. English farm ... ... ... ... ... 1.4405 English Yeovil.. ... 1.4391 Cocoanut oil ... ... ... ... ... 1.4321 Sample H (20 per cent.) ... ... ... 1.4365 . ... ... ... From the above it is clear that the refractions of the residues obtained after freezing out differ very little except as regards the amount of unsaturated fatty acids present . It now became advisable to attempt to determine approxiaately the composition of various butters and cocoanut oils. For this purpose pure southern butter (Yeovil), Finnish, Siberian, and two cocoanut oils obtained from different sources, were selected.The fatty acids of these samples were each frozen out as before, using a concentration of 10 grams in 50 c.c., both of ether and alcohol, and 20 C.C. of ether for washing purposes. The residues were all collected, dried, and weighed, and their constants determined. The results of these determinations are given in the following tables. I n every case the molecular weight of the saturated fatty acids, corrected for unsaturated fatty acids calculated as oleic acid, is given under the heading M-0. For sake of comparison a number of constants of certain pure fatty acids are also given : ORIGINAL SAMPLES. Sample. English farm (N) ... ...... ... Finnish ... ... ... ... ... ... Siberian ... ... ... ... Cocoanut oil (F) ... ... ... ... Cocoanut oil (original) ... ... ... ... Cocoanut oil (Hj' ... ... . . . Refrac- tometer Reading a t 45" C. 40.0' 38.0" 39.0" 3 1 -0" 31.0' 31.0' Polenske Value. 2.8 1.8 2.3 17.5 11.5 16.1 INSOLUBLE VOLATILE FATTY ACIDS. Reichert- Meissl Value. 29.3 25.7 23.4 7.7 7.8 8.2 Sample. Refrac- t om e t er Reading at 45" C. Molecular Weight. Iodine Value. Cocoanut oil (H). .. r . . Cocoanut oil (F) ... ... 361.2 345.0 155.3 162.7 Nil Nil460 Refrac- tometer Reading a t 45" C. THE ANALYST, ORIGINAL FATTY ACIDS. Refrac- tometer Reading a t 60" C. Sample. 30.0" 24.0" 29.0" 17.0" 24.0" 16.0" Yeovil butter (S) ... Finnish ,, ... ... Siberian ,, ... ... Cocoanut oil (H) ...Cocoanut oil (F) ... Cocoanut oil (original) - - - - - - Yeovil butter ... Finnish ,, ... ... Siberian ,, ... ... Cocoanut oil (H) . . . Cocoanut oil (F) ... Yeovil butter + 20 per cent. cocoanut oil - I - 20.0" - 28.0°c* Yeovil butter ... Finnish ,, ... ... Siberian ,, ... ... Cocoanut oil (H) ... Cocoanut oil (F) ... Yeovil butter + 20 per cent. cocoanut oil 20.0" 14.3 212.7 20.5" 24.2 187.8 25.0" 41.1 188.8 12.0" 6.7 224.2 - 3.1 198.5 19*Ooc* 8.0 2240 Yeovil butter ... Finnish ,, ... ... Siberian ,, ... ... Cocoanut oil (H) ... Cocoanut oil (F) ... Yeovil butter + 20 per cent. cocoanut oil 34.0" 25.0" 29.5" 15.5" 22.0" 32.5" 26.0" 56.6 216.4 17.0" 38.6 205.8 21.5" 47.1 209.3 8.0" 8.4 266.0 - 6.0 253.3 - 44.9 226.5 Iodine Value. 45.9 39.7 42.2 8.9 8.8 8-8 207.2 207.2 198.8 254.8 244.3 - RESIDUES FROM E &'HER.RESIDUES FROM ALCOHOL. 29-O0c* 23.5' 27.0' 25.0" 28.5" - 21.0' 15.5" 19.0" - - - 13.6 31.7 39.7 6.6 25.9 - 205.1 205.8 212.2 235.2 226.8 - UNFREEZABLE RESIDUES. Molecular Weight. 270.7 270.7 280.2 220.1 229.6 - 264.1 298.7 296.8 229.7 282.6 250.4 273.5 272.6 263.6 238.5 247.4 - 259.2 272.6 268.0 210.9 221.5 247.7 M-0. 258.9 261.6 278.6 213.2 223.8 - 260.7 305.0 309.3 225-5 282.6 247.3 272.0 267.5 249-1 235.1 - 233.4 220.5 265.5 252.7 203-6 217.1 213.5 Percentage frozen out. - - - - - - 22.0 12.5 36.1 64.1 14.3 13.6 12.0 22.1 27.5 Nil 59.6 45.7 Percentage left. 66.0 65.4 36.4 35.9 26.1 40.7 * Calculated from the higher temperature reading.THE ANALYSTo 461 CONSTANTS OF FATTY ACIDS. Acid, S t earic ... ...Palmitic ... ... Oleic ... ... ... Myristiu .. , ... Lauric ... ... Capric ... ... Claprylic ... ... Caproic *.. ... ... ... Refractometer Reading at 45" C. Refractonieter Reading a t 75" C. 12.0" 8-5" 25.5" 7.5" - - - - Molecular Weight. 284 256 282 228 200 172 144 116 From the above figures it is evident that, with the exception of oleic acid, the Zeiss refractometer figures are not sufficiently distinctive to be of much service. On the assumption that, besides oleic acid, only two acids are present in each fraction, the approximate composition has been calculated from a consideration of the iodine value, as a measure of the oleic acid, and from the percentages frozen out. The nature of the two remaining acids was derived from the molecular weights of the saturated fatty acids in the column M-0, These figures are given below : Acids. Oleic ...... ... ... Stearic and higher ... ... Stearic and palmitic ... Acids. Oleic ... ... ... ... Stearic and palmitic ... Myristic and lauric ... ... Acids. Oleic ... ... ... ... Palmitic and a little myristic Stearic and higher ... ... Mostly palmitic ... . . I Acids. ... ... ... Oleic ... Myristic ... ... ... Mostly lauric ... ... Finnish Butter. Per Cent. ... 39.3 ... 9.1 ... 51.6 Yeovil English 13ntter. Per Cent. ... 46.8 .. 28.8 ... 24.4 Siberian Butter. Per Cent. .. 47% ... 19.7 ... 15.4 ... 17.3 Cccoanut Oil (H). Por Cent. ... 8.0 ... 59.4 ... 22.6 Saturated Fatty Acids. Per Cent. 15.0 85.0 - Saturated Fatty Acids. Per Cent. - 54w0 46.0 Saturated Fatty Acids. Per Cent. 37.6 29.4 33-0 - Satnrated Fatty Acids.Per Cent. 64% 35.4 - * Calculated from the higher temperature rcading.462 THE ANALYST, Cocoanut Saturated Per Cent. Per Cent. Acids. Oil (F). Fatty Acids, - Oleic ... ... ... ... ... 6-6 Stearic ... ... ... ... 13.8 14.8 Palmitic and myristic ... ... 55.3 59.3 Myristic and lauric ... ... 24.3 25.9 From a consideration of the above tables, it seems probable that, as regards the insoluble fatty acids, the variations in the composition of different butters and cocoa- nut oils are so great among themselves that the fixing of reliable constants becomes practically an impossibility. In some instances there is little difference between butters and cocoanut oils, except as regards the amount of unsaturated acids present. Thus, cocoanut oil (F) approaches so nearly to English butter (P) that an addition of 20 per cent.of it to the butter gave but a very slight indication in any of the constants. As regards the unsaturated fatty acids, these seem to be the principal cause of the variations in the refractions on the unfreezable residues, and this determination is therefore useless. I t is evident that the same saturated fatty acids are present in nearly all cases, although in variable quantities. The butters from the northern countries contain less oleic acid, and probably in some instances a higher acid than stearic. A further attempt was made to examine the saturated fatty acids as a whole by removing the oleic acid. Ten grams of the fatty acids were treated with excess of a concentrated Hiibl solution, and the iodo-compound separated in hot brine by difference in density from the saturated fatty acids.The latter were then saponified, reprecipitated, and filtered. The following constants were obtained, but the differences are too small to allow of any accurate deductions : Saturated Molecular Fatty Acids. Weight. Finnish butter ... ... 58.6 ... 256.0 Sample . Cocoanut oil (F) ... ... 90.0 ... 215.0 Cocoanut oil (H) ... ... 87.0 ... 210.7 These figures tend to confirm the previous ones, and seem to show the futility of attempting to differentiate between cocoanut oil and butter by any consideration of the characteristics of their insoluble fatty acids. I n conclusion, I wish to thank my.assistant, Mr. F. Maudsley, for the assistance he has rendered in carrying out this investigation. DISCUSSION.Mr. F. W. RICHARDSON asked whether the author had met with many samples of butter with abnormally high Polenske numbers. For a long time the Polenske numbers which he (the speaker) had been obtaining had been normal, but some years ago a number of samples from one district had given Polenske numbers as high as 44,THE ANALYST. 463 and as all the other data pointed to the presence of cocoanut oil he had felt bound to condemn those samples. No sample with an abnormally high Polenske number had since come to him from that district, and he had never since met with a butter showing indications of cocoanut oil. It would be interesting if the author could account for the method giving such good results with the samples provided by Mr.Bevan while it broke down with other samples. Rlr. HEHNER said that at one time, in conjunction with Mr. C. A. Mitchell, he had made some hundreds of determinations of stearic acid in butter, and their con- clusion was that butter, as a general rule, contained less than 1 per cent. of stearic acid, although certain exceptions, due to abnormality, made this fact useless for the object they had in view. These exceptions occurred in the case of some Russian samples with very low Reichert- Wollny figures. Mr. E. R. BOLTON asked whether the author had made any experiments with butter containing other fats in addition to cocoanut oil. Probably cocoanut oil was not very often added alone to butter ; at any rate he had never met with such a case. It would almost certainly be added in conjunction with other fats in the form of margarine, which might considerably alter the conditions as to solubility. Mr. Ross said that as regards Mr. Bevan’s samples the probability seemed to be that in those cases the butter was either from the North of England or from Ireland. All the Irish butters he had examined had behaved normally. With Danish butter, too, good results would probably be obtained. The highest Polenske number he had ever found was about 3.0. I n the cases now referred to the highest was 2-8, and it would probably be considerably lower than that in butter from northern countries. He had been making experiments with about half a dozen fats other than cocoanut oil, but had not yet had time to complete them.

ISSN:0003-2654    

DOI:10.1039/AN9083300457

出版商:RSC    

年代:1908

数据来源: RSC

摘要:

THE ANALYST. 463 THE ANALYSIS OF CAMPHORATED OIL FOR CAMPHOR SUBSTITUTES. BY F. W, RICHARDSON, F.I.C.; AND W. WALTON. (liead at the .iMeeting, November 4, 1908.) THE estimation of natural camphor in camphorated oil can be easily accomplished by direct polarimetry. Our results confirm those of Leonard and Smith (ANALYST, 1900, 25, 202), which, again, are in fairly close agreement with the figures given by Chabot (Con~pt. rend., 1890, 111) 231) and Dowzard (British Food JozwnaZ, 1900, p. 69). The reading given in a 100-millimetre tube in a Schmidt and Haensch instrument multiplied by 0.69 gives the percentage of camphor in camphorated oil on the volume. This figure divided by 0.926-the specific gravity of the oil at 15.5" C.-gives grams of camphor in 100 grams of the oil. Our attention was first called to the question of camphor substitutes when we found a camphorated oil devoid of optical acbivity, while the other analytical data464 THE ANALYST.were quite in accord with those of a genuine sample. Distillation in a current of carbon dioxide gave us pure artificial camphor. With some diffidence we would ask if there is any good reason why artificial camphor may not be used in place of the natural article. With the exception of its optical inactivity, it agrees in all other essentials with ordinary camphor. By the depression of freezing-point method we found the molecular weight of natural camphor to be 152.10 (Theory 152*016), and for artificial camphor we obtained 150.6, showing the close similarity of the two bodies. The method of manufacture of the artificial preparation points to its identity with the natural article.According to A. F. Collins (Journ. SOC. Chem. Ind., 1904, 23, 75), turpentine is heated with anhydrous oxalic acid, and the pinyl oxalate aud pinyl formate produced yield camphor and borneol respectively when distilled with steam. If it can be shown that the rubefacient properties of the artificial article are identical with those of natura.1 camphor, the possession of symmetry in one and of asymmetry in the other case would be no argument against substitution, This is, perhaps, rather a question for the medical profession than for the public analyst to decide. We propose to deal with the analysis of natural and artificial camphor, oil of turpentine, and essential oil of camphor. Camphorated oil lends itself almost entirely t o physical methods of analysis. If the specific gravity, refractive index, and polarirnetric reading are all normal, there is little doubt as to the genuineness of the sample.If in addition the loss on drying in shallow layers at 100" C. and the iodine number are normal, all doubt as to the purity of a sample is removed. When substitutes for camphor have been used, further data are necessary. As the samples supplied under the Food and Drugs Acts are usually under one fluid ounce, we do not use more than 10 grams for the analysis. This weight of the camphorated oil is placed in a dry 2-ounce retort, the tubulure of which is connected with a weighed two-necked 4-ounce Woulff'e's bottle immersed in ice ; a weighed small spiral glass condenser passes through the cork in the second hole of this receiver. A current of dry carbon dioxide is passed through the oil in the body of the retort, placed in an oil-bath heated to 200' C.I n the case of camphors the tubulure of the retort condenses almost all the volatile bodies, which appear in characteristic white crystalline masses. The portion of the tubulure containing the sublimate is cut off by means of a file, tho weight determined, aud the contents rinsed into a tared flask by means of carbon tetrachloride. The weight of the dried tubulure deducted from the first weighing represents most of the camphor. Any that remains will be found in the Woulffe's bottle, and the condenser connected therewith. As these pieces of apparatus have been weighed, any increase gives the additional volatile products.These extra portions are dissolved in carbon tetrachloride, and are added to the first bulk. This solution is weighed, and portions are used for- (1) specific gravity ; (2) iodine number ; and (3) polymerisation with sulphuric acid. The last-mentioned process is carried out as follows : About half the liquid is placed into a 4-ounce round-bottomed flask with side-tube, the exact weight being By oxidation the borneol is converted into camphor.THE ANALYST. 465 ascertained. One-third its volume of sulphuric acid (specific gravity 1-84) is slowly added, followed by a brisk agitation, and, if necessary, immersion in cold water to reduce the temperature. After about five minutes the side-tube is connected with a Liebig's condenser, which in turn is connected with an 8-ounce glass separator. A current of steam is passed through the flask until the separator is nearly full.Some of the lower layer of carbon tetrachloride is drawn off to rinse out the condenser tube, which is again rinsed with fresh solvent. The combined carbon tetrachloride solutions are placed in a tared flask and weighed. Polymerisation is so complete in the case of turpentine and essential oil of camphor that no optically active substance distils over ; 95.0 per cent. of the camphors are left unchauged and volatilise. The change in the specific gravity and refractive index of the carbon tetrachloride solution enables us to calculate the weight of the total camphors, while the polarimetric reading in a 200 mm.tube, multiplied by 0.22385 and divided by 0.95, gives the natural campho?.. This deducted from the total camphors estimated by the change in the specific gravity of the solvent leaves the artificial camphor. If there is no reading, natural camphor is absent. In the -firat distillation in a current of carbon dioxide any artificial camphor will have beeu actually seen, as the turpentine and essential oil of camphor distil over first, and the crystals of the camphor can be seen forming in the neck of the retort. In calculating the following iodine numbers are assumed : Camphor-natural, 5 ; artificial 7 ; essential oil of camphor, 180; oil of turpentine, 370. (By the odour emitted on warming it is usually easy to ascertain whether or not essential oil of camphor is present in appreciable amount.) Distillation of the original camphorated oil at 200" C. in a current of carbon dioxide effects a complete removal of the camphors, as the following data show * Camphors actually Present.Camphors recovered. Per Ceiit. Per Cent. (I) ... ... 19.30 ... ... ... 19.40 (2) ... ... 20.73 ... ... ... 20.60 (3) . . < ... 21.00 .. ... ... 21.14 (4) ... ... 21.00 ... ... ... 20.87 Average 21.00 ... ... ... 21.00 The olive oil thus freed from camphors remains unchanged, as far as its physical properties and iodine numbers are concerned. It is, therefore, a simple matter to eliminate the oil values from the data obtained in the analysis of the camphorated oil itself. When the amounts of the two camphors are known, the iodine number due to turpentine and oil of camphor enables us to calculate the percentages of these last-named bodies. A number of special mixtures were prepared, and the following results were obtained on analysis : As the analyst in this case was quite ignorant of the composition of the oils he was examining, except that he knew the four kinds of substances which might be used, the results were much more satisfactory than we had hoped.466 THE ANALYST.Found. Per Cent. No. 1 MIXTUBE : Olive oil ... . . 80.60 Natural camphor . . . 9.70 Turpentine ... 9.70 NO. 2 MIXTURE : Olive oil ... ... 79.60 Artificial camphor 6.12 E s s e n t i a l o i l of camphor.. . ... 14.38 No. 3 MIXTUBE : Olive oil ... ... 79.40 Natural camphor . . . 13.73 Artificial camphor 6.87 Actual.Per Cent. 80.70 9.56 9.74 79.89 6-03 14.08 7947 13-80 6.93 Found. Yer Cent. No. 4 R~IXTUHE : Olive oil ... ... 79.83 Natural camphor ... 12-94 Turpentine . . . 7.23 No. 5 MIXTURE : Olive oil ... ... 79.43 Artificial camphor 12.66 Turpentine ... 7.91 No. 6 MIXTURE : Olive oil ... ... 74-20 Natural camphor . . . -80 Artificial camphor 15.20 E s s e n t i a l o i l of camphor.. , ... 9.80 Actual. Per Cent. 79.84 13.36 6.81 79-90 12-25 7.85 73.96 None 15.06 10.98 DISCUSSION. Mr. CHAPMAN suggested that, since what the authors referred to as ‘( artificial camphor,” was really “ synthetic camphor,” it would be better to use the latter term throughout. The term ‘( artificial camphor )) was apt to be a little confusing. Mr. SEYLER thought it could not be agreed that Synthetic camphor was a proper substitute for natural camphor in medicine until it had been proved to have the same physiological effect.The instance of artificial salicylic acid, which had recently been investigated, showed the necessity for caution in such matters. The CHAIRMAN (Mr. John White) asked if Mr. Richardson had any actual experience of the rubefacient properties of synthetic as compared with natural camphor. Mr. RICHARDSON said, judging from a few experiments he had made and from the physical properties of the synthetic camphor, he should say that its rubefacient properties were identical with those of natural camphor. Mr. D. L. HOWARD said that, although synthetic camphor had been for some years in use in the arts, it was, as far as he knew, only recently that it had been offered to the drug trade. I t seemed very important to decide whether it was a fit; and proper substitute for natural camphor in medicine. Camphorated oil, of course, was only the first step, and there might be no objection to the use of synthetic camphor externally; but it was only a short step to camphorated chalk, used as a dentifrice, and from that again to spirit of camphor, used as a stimulant. I t seemed highly necessary, especially in view of what had been experienced in the case of artificial salicylic acid, etc., that an authoritative research should be made as to whether the diff’erence in optical properties between synthetic and natural camphor had reference to any difference in therapeutic action.

ISSN:0003-2654    

DOI:10.1039/AN9083300463

出版商:RSC    

年代:1908

数据来源: RSC

摘要:

THE ANALYST. ABSTRACTS OF PAPERS PUBLISHED - 467 IN OTHER JOURNALS. FOODS AND DRUGS ANALYSIS. The Estimation of Alkaloids in Extracts of Belladonna and Hyoscyamus. E. Rupp. Chem. Zeit. Rep., 1908, 32, 529.)-Three grams of belladonna extract or 5 grams of hyoscyamus extract are dissolved in 5 (or 8) C.C. of hot water, and the cold solution shaken for fifteen minutes with 90 C.C. of ether and 1 C.C. of ammonia solution, and then allowed to stand for fifteen minutes. Sixty C.C. of the ethereal layer are then filtered through cotton- rvool into an Erlenmeyer flask, and the ether evaporated on the water-bath. The cotton filter is washed with three portions of 5 C.C. each of ether, and the washing evaporated each time in the flask. The residue is dissolved in a few C.C. of warm alcohol, and the solution mixed with 20 C.C.of & acid and about the same amount of water. Should the solution be coloured, it is shaken with 5 to 10 C.C. of ether in a separating funnel, the aqueous layer drawn off, the ether shaken twice with portions of 10 to 15 C.C. of water, and the aqueous washings added to the main liquid. The latter is now covered with a layer of about 1 cm. in depth of ether, and titrated brtck, with i$u. alkali solution, after the addition of 5 to 10 drops of iodeosin solution as indicator. The proportion of alkaloids should not be less than 1 per cent. in belladonna extract, nor less than 0.5 per cent in hyoscyamus extract. (Pharm. Xeit., 1908, 53, 738. C. A. M. The Colorimetric Estimation of Benzaldehyde in Almond Essences. A.G. Woodman and E. F. Lyford. (Jown. Amel.. Chem SOC., 1908, 30, 1607- 1611.)-It is shown that benzaldehyde may be estimated in almond essences by means of fuchsin-sulphurous acid (SchiE’s reagent) if care be taken in the preparation of the reagent and in the removal of all aldehyde from the alcohol used in diluting the test solutions. The reagent is propared by dissolving 0.5 gram of pure fuchsin in 100 C.C. of water, adding a solution of sulphurous acid containing 20 grams of sulphur dioxide, and diluting the whole with water to a volume of 1 litre. The solution may be used for ten days after being made; owing to the sulphuric acid formed by oxidation of the sulphur dioxide the sensitiveness of the reagent is so diminished that it then becomes useless. To remove aldehyde from ordinary alcohol, it is recommended that the latter be treated with silver oxide and distilled; to the distillate are then added 25 grams of m-phenylenediamine per litre, and a fairly rapid current of air is drawn through the mixture for three hours.The alcohol is next; distilled, the first 100 C.C. being rejected. A standard solution of benzaldehyde is prepared by dissolving such a, quantity of the freshly distilled aldehyde in the purified alcohol that each C.C. contains 0.001 gram of benzaldehyde. As each C.C. of com- tnercial almond essence contains approximately 0.009 gram of bensaldehyde, an amount of the essence containing enough benzaldehyde to give the colour best suited for comparison would be too small for convenient measurement. Consequently, 10 grams of the essence are diluted to 50 C.C.with aldehyde-free alcohol. Two C.C. of468 THE ANALYST. the solution are placed in a colorimeter tube, and diluted to 20 C.C. with alcohol; three standard solutions are then made up containing, say, 0.002, 0.004 and 0.006 gram of benzaldehyde, and placed in similar tubes. All the tubes are placed in a water-bath at a temperature of 1 5 O C. ; when the contents of the tubes have reached this temperature, 20 C.C. of the reagent (also at 15' C.) are added to each tube, and, after thorough mixing, the tubes are allowed to stand for ten minutes. The colora- tion in the sample tube is then compared with those of the other tubes. Within the above limits the depth of colour is proportional to the concentration of benzaldehyde.w. P. s. The Analysis of Cacao Butter. G. Halphen. (Jo?(r1z. Pharm. Cllim., 1908, 28, 345-346.)-A method of detecting certain vegetable fats, such as bcurrc w i - t and other preparations of cocoanut oil in cacao butter, is based upon the difference in solubility of the respective bromine derivatives. A solution of the fat in twice its volume of carbon tetrachloride is treated gradually with an excess of a highly con- centrated solution of bromine in the same solvent, the liquid filtered through a mixture of equal parts of sand and starch, and the filtrate mixed with four to five times its volume of petroleum spirit, and cooled for two hours in water at 15" C. I n the case of pure cacao butter the liquid will remain perfectly clear, whereas an abundant precipitate will be formed by beurw vert, or by a mixture of cacao butter with 10 per cent.or more of that fat. If, instead of diluting the liquid with four to five times its volume of petroleum spirit, only two to three times the volume be used, it is possible to detect as little as 5 per cent. of the adulterant, especially if com- parative tests be made with pure cacao butter. For the detection of beuwe vert in chocolate the fat is extracted in the ordinary way and dissolved in carbon tetrachloride in the proportion of 2 C.C. per gram, and the solution boiled with animal charcoal under a, reflux condenser, and then cooled and filtered. One C.C. of the colourless filtrate is treated drop by drop with a solution of bromine in carbon tetrachloride until the liquid remains red.After standing for about two minutes the liquid is mixed with 3 C.C. of petroleum spirit of specific gravity 0.700, and the tube closed and allowed to stand over-night. With pure cacao butter the liquid remains clear, while in the presence of even 5 per cent. of beurre u c ~ t there is a slight deposit, and a pronounced precipitate with larger proportions of the adulterant. C. A. M. A New Adulterant of Fennel Seed. C. Arragon. (Zcits. U&rsPich. Nahr. Gemssm., 1908, 16, 400-402.)-The author has examined a sample of fennel seeds which contained 72.8 per cent. of true fennel seed, 16.7 per cent. of foreign seeds (mostly sea-damaged wheat grains, together with a few poppy and vetch seeds), and 10-5 per cent. of small stones. The latter were of particular interese, as they consisted of small fragments of marble coloured with iron ochre.Even the fennel seeds themselves were not of good quality, many of the seeds being quite tasteless, and had evidently been extracted or exhausted previously. The portion of the sample, consisting of good and bad fennel seeds, gave the following results on analysis: Aqueous extract, 16.5 per cent. ; alcoholic extract, 5.6 per cent. ; fat,THE ANALYSTo 469 5.2 per cent. ; ethereal oil, 1-5 per cent. ; total ash, 7.4 per cent. (cf. ANALYST, 1899, 24, 127). w. P. s. The Deterioration and Commercial Preservation of Flesh Foods. Experiments on Frozen Beef. W. D. Richardson and E. Scherubel. ( J o z m . Amer. Chem. Soc., 1908, 30, 1515-1564.)-The chemical work recorded in this paper was begun with the object of determining whether or not there was progressive change in the chemical constituents of the meat, such as would result in an increase of the soluble constituents due to the autodigestion of insoluble proteins, and also an increase of the Nearly all the experiments were carried out on the portion of meat known to butchers as the knuckle,” and the lean part of the meat was used as far as possible, The fresh samples varied in age from 0 to 7 days, and from the time of slaughter were stored in a temperature which varied from 2’ to 4” C.The frozen samples varied from 33 to 554 days in age, and were stored, while frozen, in a room whose temperature ranged from - 9” to - 12” C. The following is a summary of the results obtained : ammoniacal nitrogen.” Ammoniacal Nitrogen.Age. Days. Moisturc. Total Nitrogen. Ash. Fat. I. 11. 77.27 7’5.26 76.35 77.11 75.32 76.39 1.31 1.11 1-23 1.29 1.16 1.23 3.34 0.78 1-43 2.12 1.17 1.65 3.65 3.34 3-49 3.65 3.31 3-51 0.033 0.022 0.029 0-031 0.024 0.028 0.011 0.009 0.010 0.013 0.009 0.01 1 Maximum Average ... Maximum 7 0 3.7 554 33 353 COLD-WATER EXTRACT. Coagu. lable Nitro- gen. Albu- mose Nitro- gen. Meat- base Nitro- gen. Acidity as Lactic Acid. Total Nitro- gen. Organic E s trac- tives. Total Solids. Ash. 6.24 5.55 6.01 6.27 5.56 5.94 1.27 0 95 1.14 1.21 0.96 1.14 5.27 4.42 4.87 5.18 4.40 4 -80 0.854 0.742 0 *806 0.861 0.730 0.795 0,034 0.014 0,024 0.026 0.021 0.023 0.398 0.360 0,355 0-379 0-337 0.357 0.82 0.63 0.68 0.92 0.66 0.79 Maximum Fresh meat Minimum Average... Maximum Average . . . { 0,452 0.358 0.413 0,468 0.353 0-413 The figures represent percentages calculated on the original meat. The ammoniacal nitrogen ‘ 4 I.” was obtained by distilling the meat with magnesium oxide, whilst the ammoniacal nitrogen ‘‘ 11.” was found by extracting the meat with 60 per cent. alcohol, and distilling the extract with magnesium oxide. The cold-470 THE ANALYST. water extracts were obtained by digesting 100 grams of the meat with successive quantities of cold water until the united extracts amounted to 1 litre. A general inspection of the tables shows that there is very little difference between the analyses of the fresh and the frozen samples, The slight variations noticeable do not tend definitely in one direction in the frozen samples, and the ammoniacal nitrogen, the coagulable nitrogen, and the albuniose nitrogen figures do not show a positive tendency to increase or decrease.No importance is attached by the authors to the slight differences in the acid figureB. No difference in flarow could be detected between fresh and frozen meat, On the whole, the results of the various lines of work given in this paper-chemical, histological, and bacteriological -all go to indicate that cold storage, at temperatures below -0.9" C. at least, is an adequate and satisfactory method of preserving beef for a period of 554 days, and probably for a much longer time. w. P. s. The Lead Value of' Maple Products. A. P. Sy. (JOZLWZ.. Anzer. Chem. Soc., 1908, 30, 1611-1616.)-By the lead value is meant the amount of lead precipitated on adding lead acetate solution to 100 grams of sugar or 100 C.C.of syrup ; this value decreases in adulterated samples as the quantity of cane-sugar increases (cj. ANALYST, 1906, 31, 411). As many different ways of obtaining the value have been proposed, all more or less trustworthy, for differentiating between pure and badly adulterated samples, the author thinks it desirable to record a method which will give con- cordant results on the same sample by the same or different analysts. The details of this method are as follows : Fifty C.C. of syrup or 50 grams of sugar are diluted with 200 C.C. of water, heated to boiling, treated with 20 C.C. of 10 per cent. neutral lead acetate solution, again boiled, and allowed to cool.The precipitate is collected on a filter and washed with water at a temperature of 20" C. The filter and pre- cipitate are then heated with 15 C.C. of concentrated nitric acid and 10 c.c.-of concentrated hydrochloric acid until the filter is disintegrated ; 10 C.C. of concentrated sulphuric acid are next added to the cooled mixture, and the heating is continued uutil sulphuric acid fumes are given off. If the resulting liquid is black, 5 C.C. of nitric acid are added, and the heating is repeated. After cooling, 50 C.C. of water and 100 C.C. of alcohol are added, and, at the end of six hours, the lead sulphate is collected on a filter, washed, dried, and weighed. The weight of lead sulphate multiplied by 1,366 gives the weight of lead precipitated by 100 c.c., or 100 grams, of the sample.The lead value of a pure maple product should not be less than 0.250, and is usually over 0.300. Six samples of maple-sugar of known purity gave values between 0.376 and 1.024. w. P. s. The Lecithin-Content of' Various Milks. J. Nerking and E. Haensel. (BI3ioehcm. Zcits., 1908, 13, 348-353,)-1n view of the conflicting statements which have beeu recorded as to the quantity of lecithin present in milk, one observer, owing to faulty wethods of extraction, having come to the conclusion that milk doesTHE ANALYST 471 not contain lecithin, the authors give the results of a number of estimations of this substance in various milks. The highest, lowest, and average results obtained were as follows : Percentage of Lecithin. Kind of Milk.Highest. Lowest . Average. Human, ten samples ... * . . ... Cows), seventeen samples ... Asses), six samples ... ... ... ... Sheep's, four samples ... ... ... ... Goats', eleven samples ... ... Mares', eight samples ... ... ... ... ... ... ... ... 0.080 0.1 16 0.039 0.167 0.075 0.174 0.024 0,036 0.006 0.051 0.036 0.007 0.050 0.063 0.016 0.083 0.049 0.011 The method employed for estimating the lecithin consisted in adding 200 C.C. of alcohol to 100 C.C. of the milk, the mixture being stirred during the addition; when the precipitate had settled, the liquid portion was passed through a filter, and the precipitate, together with the filter paper, was extracted in a Soxhlet apparatus with chloroform for thirty hours. Meanwhile, the alcoholic filtrate was evaporated at a temperature of from 50" to 60" C., and the residue extracted thoroughly with chloroform, The two chloroform solutions were then united, evaporated in a, platinum basin, and the residue, after the addition of sodium carbonate and potassium nitrate, was ignited. The phosphoric acid in the ash was next separated by means of molybdic acid and weighed as magnesium pyrophosphate.No attempt was made to separate the lecithin from the cephalin, the main object of the investigation being the estimation of the total phosphatides present in the milks. w. P. s. The Constituents of Expressed Oil of Nutmeg. F. B. Power and A. H. Salway. ('rrans. Chem. SOL, 1908, 93, 1653-1659.)-As the result of their investigation the authors find that the approximate composition of genuine expressed oil of nutmeg (nutmeg butter) is as follows : Per Cent.Essential oil ... ... ... ... ... 12.5 Olein ... ... ... ... ... ... 3.0 Linolein ... ... ... ... ... 0.5 Resinous matters ... ... ... ... 2-0 Trimyristin ... ... ... ... ... 73.0 Formic, acetio, and cerotic acids ... ... (very small amounts) Unsaponifiable matters ... ... ... 8.5 The unsaponifiable matter consisted of a new compound, C,8H,,0, (amounting to about 5 per cent. of the expressed oil), together with some myristicin, CllH1208, and a very small amount of phytosterol. Although the myristicin is a constituent of the essential oil, it was not practicable to effect its complete removal by the preliminary treatment of the fat with steam. The oil employed in the investigation472 THE ANALYST.was obtained from a portion of the same lot of Ceylon nutmegs as that from which the essential oil previously examined had been distilled (cf. ANALYST, 1908, 52). Some of the Constituents of Saffron and a Method for the Valuation of Saffron. B. Pfyl and W. Scheitz (Zeits. Unterszdz. Nnh-. Genussm., 1908, 16, 337-352.)-Three crystalline substances were isolated from the petroleum spirit and chloroform extracts of pure saffron. The substance which was extracted by means of chloroform was similar to the picrocrocin described previously by Kayser, in that it yielded a sugar and an ethereal oil on hydrolysis; this sugar was lzvo-rotatory, and gave an osazone corresponding to that of dextrose or laevulose, but did not yield dextrose-P-naphthylhydrazone. The picrocrocin obtained by the method given by Kayser (Berich, 1884, 35, 2228) could not be crystallised.Extraction of the saffron with absolute alcohol (after treatment with petroleum spirit and chloroform) resulted in a sugar being obtained having the same properties as the above- mentioned sugar, and a glucoside, which on hydrolysis furnished a further quantity of the same sugar, together with an ethereal oil. The authors consider that this sugar is llievulose. The method proposed for the valuation of saffron depends on the estimation of the reducing sugars present in the drug. The sample under examination is dried in the water-oven, powdered, and again dried. Five grams of the dried powder are then extracted for one hour in a Soxhlet apparatus with petroleum spirit.The cartridge containing the powder is next carefully heated until all the petroleum spirit has been removed, and the powder is then extracted for two hours with chloroform. The chloroform extract is evaporated, the brown residue is taken up with hot acetone, and the solution is poured into 25 C.C. of water contained in a small beaker. The mixture is boiled until the acetone has been driven off, and the heating is continued after the addition of 5 C.C. of hydrochloric acid for a further fifteen minutes, any loss by evaporation being made up by the addition of a little water from time to time. When cold, the solution is filtered; the filtrate is neutralised by the addition of alkali solution, and added to a boiling mixture of 50 C.C. of Fehling's solution and 25 C.C.of water. The whole is boiled for a further two minutes, and the precipitated cuprous oxide is collected, washed, and weighed as metallic copper. Genuine saffron (Crocus Gatiizuis electus) yields about 0.209 gram of metallic copper when examined in this way : samples containing an undue proportion of pistils, or adulterated in other ways, yield smaller amounts of copper. The usual adulterants of saffron-namely, safflower (Carthamus tinctoriz~s), marigold (Cnleizdzda oficinalzs), sandal-wood, turmeric, logwood, peony petals, etc.-yield no chloroform-soluble substance which reduces Fehling's solution. As the quantity of cuprous oxide precipitated is not proportional to the amount of sugar present, but varies with the concentration of the latter, it is necessary, in calculating the percentage of genuine saffron in an adulterated sample, to make use of the following table, which gives the quantities of copper corresponding with different weights of pure saffron : (;ran~s.Gral~~s, Grams. Graiiis. Grams. Grams. (;rams. Grams. Grams. Weight of sample take11 5.0 4.5 4'0 3.5 3.0 2.5 2.1 1'2 1.0 Copper ... ... .,. 0'2090 0*1870 0.1619 0.1120 0'0828 0'0614 0.0476 0'0264 0'0230THE ANALYST 473 Suppose 5 grams of a sample yield 0.0661 gram of copper : this number is not given in the table, but the next lowest number is 0.0614, corresponding with 2.5 earns of saffron. The actual quantity of saffron present is then obtained by interpolation, and the percentage is calculated. Analyses of test mixtures are given ahowing that the mothod is trustworthy.w. P. s. The Examination of Alcohol-free Wines. J. M. Krasser. (Zeits. Untersuch. Nahr. Genussnt., 1908, 16, 398-400.)-The following results were obtained on the analysis of six samples of alcohol-free wine, the figures expressing grams per 100 C.C. : Traminer (red) ... Kalterer (red) ... Terlaner (white) Mailbergel (white) Moorer (white) Villanjer (red) ... Specific Gravity 1.0230 1.0298 1-0263 1.0220 1.0294 1.0273 Alcohol, 0.37 0.21 0.21 0.16 0.21 0.26 Total solids 647 8.35 6.77 5.71 8.16 7-88 Ash. 0.17 0.17 0.13 0.13 0.16 0.15 Total. Acid (as Tar. taric). 0.59 0.55 0.68 0.66 0.75 0.61 Volatilc Acid Ace tic). ("9 0.1 5 0.08 0.06 0.05 0 -05 0.05 Gly- cerol. 0.20 0.23 0.14 0.10 0.28 0.29 Pot,assium Hydrogen Tartrate. 0.21 0.20 0-26 0.26 0.28 0.19 Invert Sugar.1 -00 0.91 4-75 4.19 3.06 1.33 Sucrose. 4-52 6.37 0.53 0-61 2.59 4.62 All the samples were free from coal-tar dyes and preservatives. They had been mixed with carbonated mineral water, and had evidently not been fully fermented before the alcohol was removed. The question is discussed whether alcohol-free wines, when sold as such, should not be wine from which the alcohol has been removed, and not simply sterilised grape juices or musts. w. P. s. The Identification of Thqjone in Liqueurs. L. Duparc and A. Monnier. (Ann. de Chem. Anal. AppZ., 1908, 13, 378-382.)-Legal's nitro-prusside reagent may be used for the detection of thujone (tanacetone) in certain liqueurs, as was shown by Cuniasse in the case of absinthe (ANALYST, 1907, 32, 119); but the coloration is fugitive and not sufficiently characteristic in the presence of carvone and essential oils of ketonic nature.These drawbacks are obviated by adding to the liquid under examination a few drops of a solution of zinc sulphate before the sodium nitro-prusside, a gooseberry-red precipitate being then obtained instead of the fugitive red coloration. The reaction is still unmistakable in a solution containing i part of thujone in 5,000. Other essential oils give more or less pronounced precipitates, but of a light colour, usually yellowish-white. Thus, oil of carvi gives tt white precipitate; carvone, a yellow precipitate; eau-de-vie de marc, a white precipitate ; and acetone, a yellow precipitate. The only substance that would474 THE ANALYST, interfere with the detection of thujone is citral, which gives an orange-red precipitate, and that could he eliminated by condensation with aniline phosphate. In applying the test, 10 C.C. of the solution (e.g., 0.2 per cent.) of the essential oil in 60 per cent, alcohol are treated with 2 C.C. of a 10 per cent. solution of zinc sulphate, followed by 0.5 C.C. of a 10 per cent. solution of nitro-prusside. After the mixture has been shaken, 4 C.C. of a 5 per cent. solution of sodium hydroxide (free from carbonate) are slowly added, the tube allowed to stand for a minute without shaking, and from 2 to 3 C.C. of glacial acetic acid then added. After a few minutes a flocculent precipitate will form. In the case of liqueurs the test is applied to 10 C.C. of the distillate. Thujone may be detected in the presence of citral, not only by condensing the latter by means of aniline phosphate, but also by shaking with ether the red liquid given by citral in the test. The liquid is immediately decolorised, while the ether becomes yellow, and in the presence of thujone LZ red precipitate is at once formed at the zone of contact of the two liquids. This treatment with ether may also be used for the detection of traces of thujone in liqueurs that do not contain citral. C. A. M.

ISSN:0003-2654    

DOI:10.1039/AN9083300467

出版商:RSC    

年代:1908

数据来源: RSC

摘要:

474 THE ANALYST, BACTERIOLOGICAL, PHYSIOLOGICAL, ETC. New Method for the Estimation of Lactic Acid in Animal Organs and Fluids. E. Jerusalem. (Biochem. Zeits., 1908, 12, 361-389.)-1n the method pro- posed, the lactic acid is extracted from the substance under examination by means of ether and then oxidised by permanganate ; the aldehyde formed is estimated by the iodometric (iodoform) method, and the quantity found is equivalent to the lactic acid present. As lactic acid is by no means readily extracted from its aqueous solution by ether, the solution should be evaporated almost to dryness, and the pasty mass then extracted. A special extraction apparatus is described for this purpose, the residue being placed in an extraction thimble contained in a wide glass tube; the ether vapours are condensed at the top of the tube, and the drops of ether, falling on to the residue in the thimble, pass through the latter and down a long vertical tube attached to the bottom of the wide tube.The lower part of this vertical tube is bent upwards in a spiral form, so that any drops of water are well extracted by the ether before the latter finally passes again into the extraction flask. The ethereal solution of the lactic acid, obtained after several hours’ extraction, is evaporated, and the residue is introduced into a flask attached to a condenser. About 150 C.C. of water and 10 C.C. of concentrated sulphuric acid are added, the solution is boiled, and potassium permanganate solution is added drop by drop by means of a tapped funnel. A current of air is drawn through the apparatus during the whole operation, and the coloration produced by each drop must disappear before the next drop is admitted.In this way the aldehyde produced is removed as soon as formed, and is not further acted on by the succeeding quantities of permanganate added. IVhen the coloration obtained on adding a drop of permanganate no longer disappears, the addition of permanganate is stopped and the current of air is continued for some time. The lower end of the condenser is connected with absorption vessels con- taining water, in which the aldehyde is collected. At the end of the operation, theTHE ANALYST. 475 contents of the receivers are mixed, rendered alkaline with sodium hydroxide, and treated with a known excesB of i: iodine solution. At the end of five minutes the mixture is acidified with hydrochloric acid, and the excess of iodine is titrated with thiosulphate solution.The quantity of lactic acid is then calculated from the amount of iodine used. Of the substances which may interfere with the accuracy of the estimation, P-hydroxybutyric acid has the most influence; but, as it is much less readily attacked by permanganate, the point at which the lactic acid is corn- pletely converted into aldehyde before the hydroxybutyric acid is acted on can usually be noted; the latter acid decolorises the permanganate extremely slowly, whilst lactic acid does so quickly. Cholesterol, succinic acid, hippuric acid, lecithin, skatol, benzene, fatty acids, bile acids, and the colouring matter of urine and bile, do not interfere with the estimation.For the estimation of lactic acid in urine, the latter is freed from albumin, rendered ainmoniacal and evaporated to a, syrup ; this is treated with hydrochloric acid, extracted with ether, and the residue obtained on evaporating the ether is heated with dilute ammonia until every trace of ether has been expelled. In the case of blood and milk, the albuminoids are removed by treatment with potassium hydrogen phosphate and phosphotungstic acid ; the filtrate is then evaporated with The estimation is then carried out as described above. ammonia, and the process carried out as prescribed for urine. w. P. s. The Action of Acids and Rennet on Human Milk. Engel. (I3iocltcnz. Zeztsch., 1908, 13, 89-lll.)-The experiments recorded show that human milk is coagulated by hydrochloric, lactic, oxalic, and sulphuric acids when the quanbity of the acid present amounts to from 2 to 3 C.C.of T6 solution per 10 C.C. of milk, and between these limits total coagulation is sharply defined. In the case of phosphoric and acetic acids from 5 to 12 C.C. of the 2G acid are required to coagulate 10 C.C. of the milk. The coagulation by rennet bears a certain relation to the amount of acid present, but the action of the enzyme is less limited than is that of the acids. Acids produce a cosgulum consisting of casein, whilst rennet precipitates a calcium com- pound of casein. w. P. s. A Reaction distinguishing Phosphoprotein from Nucleoprotein and the Distribution of Phosphoproteins in Tissues.R. H. A. Plimmer and F. B. Scott. (Trans. Chenz. SOC., 1908, 93, 1699-1721.)--The test depends on the fact that the whole of the phosphorus (except for a negligible quantity) is eliminated as phosphoric acid from a phosphoprotein by treating the latter with 1 per cent. sodium hydroxide solution for twenty-four hours at a temperature of 37' C., whilst other organic phosphorus compounds, such as nucleoproteins, lecithin, glycerophosphoric acid, and nucleic acid, do not yield inorganic phosphoric acid when so treated. The method consists in coagulating the tissue with alcohol, thoroughly extracting the lecithin with alcohol and ether, and then treating the coagulated protein with 1 per cent. sodium hydroxide solution, after the phos- phates have been removed by repeated extraction with very dilute hydrochloric acid.I t is shown that phosphoproteins are present in milk, egg-yolk, and in the476 THE ANALYST, ova of fishes ; that is, thuy &re mainly distributed in the substances which constitute the food-stuffs of the embryo bird and fish and the young mammal. A small quantity of phosphoprotein is also present in the pancreas. w. P. s. Reliability of Methods used for Estimating Sugar in Urine. C. Funk. (Zeitscli. yhysiol. Clzem., 1908, 56, 507-511.)-Differences which have been observed between the results obtained by the polarimetric method and Bang’s method (ANALYST, 1907, 32, 180) for the estimation of sugar in diabetic urine are not d m to the presence of an unknown sugar, but to the fact that the urine contains P-hydroxybutyric acid.The latter is without influence on the results obtained by Bertrand’s volumetric process, in which the cuprous oxide precipitated by the sugar from Fchling’s solution is dissolved in ferric sulphate solution, and tho ferrous sulphate produced is titrated with permanganate. The author considers that, whilst Bang’s method is trustworthy for the estimation of pure sugars, it is useless for the examination of diabetic urine. w. P. s. A Colour Reaction of‘ Diabetic Urine. 0. Gaupp. (Biochenb. Zeitsch., 1908, 13, 138-141.)-A reaction described by Strzyzowski (Therap. Monatsclz., 1905) as being indicative of severe diabetes, is based on the formation of a green fluorescent coloration when the urine of the patient is treated with a 5 per cent. formaldehyde solution and allowed to stand for forty-eight hours. The author finds, however, that this reaction is not chwacteristic of diabetes, but is given by the urine in most cases of cachexia. The coloration is due to an inzrease in the amount of ammonia in the urine, and to the simultaneous presence of aceto-acetic acid, and may be produced artificially by mixing ammonia, aceto-acetic acid, and formaldehyde. w. P. s.

ISSN:0003-2654    

DOI:10.1039/AN9083300474

出版商:RSC    

年代:1908

数据来源: RSC

摘要:

476 THE ANALYST, ORGANIC ANALYSIS. Detection of Certain Animal Fats in admixture with Other Animal Fats. E. Polenske. (Arbeit. Kaiserl. Geswadlieitsarnte, 1908, 29, 272-275.) -Referring to the method described previously (ANALYST, 1907, 32, 382), the author states that the melting-point of the fat is more readily observed if a comparison capillary tube, filled with a clear oil, be fixed in the field of observation, and that, in determining the solidifying-point, about 1 C.C. of concentrated sulphurio acid should be introduced into the air-jacket surrounding the test-tube, in order to remove traces of moisture which may condense on the sides of the tube. Further determinations confirm the '' difference value" given previously (Zoc. cit.) for lard. In the case of goose-fat, values were obtained varying from 14.7 to 16-7.Butter should not be considered as adulterated with lard or other fat even when the sample gives a, higher value than that recorded for pure butters, if a mixture consisting of 75 parts of the sample and 25 parts of beef-fat yields a higher value than 15, and if at the same time the original butter yields a value below that given by the mixture. w. P. s. Natural and Artifleial Asphalt. J. Marcusson and E. Eiekmann. (Chenz. Zeit., 1'308, 32, 965-967.)-The presence of coal-tar pitch in asphalt may be detectedTHE ANALYST. 477 by its characteristic odour, by its content of free carbon (up to 21 per cent.), by the anthraquinone reaction, and by the behaviour of the products of distillation towards alcohol and concentrated sulphuric acid.Graefe’s diazobenzene chloride test (ANALYST, 1907, 31, 204) indicates, contrary to Graefe’s statements, either pitch from ordinary coal-tar or from brown coal-tar. Pitch from fats is recognised by the smell of acrolein obtained on heating, by the high acid content of the first distillates, and by the acid and saponification values of the alcohol-ether extracts. If the above are absent, mineral oil pitch may be looked for as follows : 50 grams of the sample are dissolved in 75 C.C. of benzene, the solution is poured into 1 litre of petroleum ether, and the filtered liquid treated three times with 75 C.C. at a time of concentrated sulphuric acid to remove resinous bodies. The liquid, filtered if necessary, is washed with water, then with alcoholic potassium hydroxide, and finally again with water.The petroleum ether is then distilled off, the residue heated for ten minutes at 105’ C., and weighed. Petroleum pitch is probably present if the oil obtained in this manner exceeds 30 per cent., reckoned on the ash-free asphalt, and if it does not “flow ” after standing for one hour s t 20” C., being, instead, pasty, and showing Vaseline-like particles. As a further test, the oil is distilled, and the distillate tested for paraffin wax by solution in alcohol-ether and cooling to - 20” C. If the oily residue contains more than 2 per cent. of paraffin, petroleum pitch is present. The test is useful only if at least 30 per cent. of petroleum pitch has been added. Artificial sulphurisation of asphalt or pitch can be detected by passing steam through the sample.Natural asphalt does not evolve more than a trace of sulphu- retted hydrogen under this treatment, whilst artificially sulphurised pitches evolve considerable quantities. A. G. L. The Diazo Reaction of Atoxyl. E. Covelli. (Chem. Zeit., 1908, 32, 1006.) -Solutions of atoxyl (sodium anilarsenate) give (1) a yellow precipitate or coloration with calciuni hypochlorite ; (2) a blue coloration with calcium hypochlorite in t.he presence of phenol and ammonia, perceptible in a liquid containing only 1 part in 100,000; (3) a yellow precipitate with reducing agents in the cold; and (4) a yellow coloration when heated with an aldehyde of the fatty series and with a mineral acid. More sensitive and characteristic than any of these reactions are those given by the arsendiazobenzol formed on treating a solution of ntosyl with a.O.5 per cent.solution of sodium nitrite and a few drops of strong sulphuric acid: ( a ) With a-naphtliylarnine hydrochloride a purple coloration is obtained. This reaction is extraordinarily sensitive, and may be used for tho detection of traces of atoxyl in urine without previous decolorisation. Thus, mine containing 0.01 gram of atoxyl gives, when treated with the reagent, a yellow colour., changing to orange, and then, after about an hour, to a purple-red, which reaches its maximum intensity in about two hours, and then slowly fades. The presence of urea or of other amino com- pounds which react with nitrous acid does not interfere with the test. Since the intensity of the coloration is proportional, under parallel conditions, to the concen- tration of the atoxyl, the reaction may also be made the basis of a, colorimetric method of estimation. ( h ) On treating the arsendiazobenzol solution with a drop of acetaldehyde, followed by a few drops of potsssiuni hydroxide solution, a carmine-red478 THE ANALYST.coloration is produced, which gradually fades, giving place to a yellow coloration The addition of a sufficient amount of the alkali solution prevents the carmine colour from fading. (c) A purple-red coloration is obtained on treating the liquid with P-naphthol, abrastol, resorcinol, morphine, dionine, or phenols, and then with potassium hydroxide. ( d ) Srsendiazobenzol behaves like sulphodiazobenzol when present in certain pathological urines which give Ehrlich's diazo reaction.(See also ANALYST, 1903, 28, 113 ; 1907, 32, 325.) C. A. M. The Products obtained on the Hydrolysis of Casein. Z. H. Skraup. (Monatsh. Chenz., 1908, 29, 791-798.)-Amongst the substances formed when casein is hydrolysed by means of acids are found three compounds having the s&me composition as leucyl-valyl anhydride. One of these is strongly laevo-rotatory, the second is slightly optically active, and the third is inactive. Diketopiperazine is also formed, probably from the amino esters of leucine and valine. Compounds having the composition of diketopiperazine are found in the Substances remaining after distilling the volatile portion of these esters under reduced pressure. Leucine, valine, and amines having the composition of butylamine and amylaminecare also present.w. P. s. Estimation of Colophony in Shellac. C. Ahrens. (Chenz. Zeit., 1908, 32, 996.)--For the detection and approximate estimation of colophony in shellac reliance is usually placed upon the iodine value, and the calculations based upon the recorded values of 10 for shellac and 125 for colophony. The author finds, however, that the iodine value of colophony shows great variations, according to the quality of the product, and may range from 110 to 164. Moreover, the absorption of iodine is incomplete after the ordinary time of interaction (six hours), but appears to be practically complete after thirty hours. These facts must be taken into account in any calculation of the proportion of colophony from the iodine value of a mixture. C.A. M. A Colour Reaction of Oleie Acid and its Use in Distinguishing Vegetable from Animal Fibres. A. Manea. (BzLZZ. SOC. de Stiinte, Bucharest, 1908, 17, 256- 257.)-When a substance such as cellulose, starch, celluloid, dextrin, or a sugar, is dissolved in strong sulphuric acid, and the solution treated with EL few drops of oleic acid or of an oil containing oleic acid, and then with water, added drop by drop with constant shaking, there is produced an intense red coloration, which changes to violet on the further addition of water. If the latter be added without shaking, a, very characteristic coloured ring is obtained. Animal fibres do not give this colora- tion, and the test therefore af'fords a rapid means of distinguishing between, e.g., true and artificial silks.If the fibres have been sized it is necessary to boil them with water, and to dry them again before applying the test. The presence of dyestuff's does not affect the production of the coloration. Certain fractions of crude petroleum, especially those distilling about 250" C., give the same colorations as oleic acid in this reaction. C. A . If.THE ANALYST. 479 A Spectrum Reaction of Oleic Acid. J. Lifschutz. (Zeitsch. physiol. Chem., 1908, 56, 446-452.)-When oleic acid is oxidised by means of chromic acid in acetic acid solution, and the mixture then treated with sulphuric acid, a solution is obtained which has a characteristic absorption spectrum. The latter shows a broad band in the green portion close to the blue, a narrower band near the yellow, and a narrow line between the orange and yellow.The test is best carried out by dissolving 1 drop of oleic acid in 4 C.C. of glacial acetic acid, adding 1 drop of glacial acetic acid containing 10 per cent. of chromic acid, and then 10 or 12 drops of con- centrated sulphuric acid. The green colour of the solution soon changes to violet or red, and the spectrum is then observed. If the coloration is too deep to allow the observation to be made, the solution may be diluted with glacial acetic acid. The test is useful for detecting the presence of traces of oleic acid in stearic or palmitic acids, etc. The test may be rendered more sensitive by heating the mixture, after the addition of the sulphuric acid, to a temperature of 70" to 80" C., and then adding chloroform until the mixture becomes lukewarm and turbid.When quite cold the mixture separates into two portions, the lower of which contains the substance giving the spectrum. The intensity of the coloration and of the spectrum is pro- portional to the amount of oleic acid present. w. p. s. Estimation of Phenol. W. A. Puckner and A. H. Clark. (Amer. Journ. Pharm., 1908, 80, 484-486.)-For the estimation of phenol in pharmaceutical products, the substance is covered with water in a round-bottomed distilling flask and connected with a steam generator and a Liebig's condenser. A current of carbon dioxide is passed through the whole apparatus for at least fifteen minutes, \\.hen steam is conducted through the material and the distillation continued until 250 C.C.of distillate have been collected, a brisk current of carbon dioxide passing during the whole of the operation. Simple saturation with carbon dioxide previously to steam-distillation only liberates about 89 per cent. of the phenol present, while about 96 to 98 per cent. of the phenol distils in the first 100 C.C. of distillate if the operation be conducted as described above. An aliquot portion of the distillate (not exceeding 50 c.c.) is then titrated with standard bromine for the volumetric estima- tion of phenol, as directed in the United States Pharmacopaia. The method is applicable even in the presence of considerable quantities of potassium hydroxide, while sulphites, bromates, and nitrates do not interfere.A. d. T. Estimation of Salicylates. A. Seidell. (Chem. Zeit., 1908, 32, 1009.)- The method is based upon the fact that on treating a solution of salicylic acid in concentrated hydrochloric acid with bromine, dibromsalicylic acid (melting-point, 220' C.) is obtained, and that at 80" to 90" C., and in the presence of a relatively small amount of water, the reaction is quantitative. From 2 to 3 grams of the salicylate are dissolved in 100 C.C. of water, and from 3 to 5 C.C. of the solution treated in a stoppered flask with from ten to twenty times the volume of concentrated hydrochloric acid, and then with N/5-potassium bromate solution, which is added, little by little, until the liquid assumes a permanenh faint yellow tint. The flask is then warmed and shaken until the yellow colour disappears, after which more480 THE ANALYST.bromate is added, and the shaking and heating repeated. This treatment is continued until the temperature has reached 80" or 90' C., and the colour produced by the addition of 2 or 3 drops of the bromate solution persists for at least fifteen minutes. Each molecule of the salicylic acid will then have absorbed four atoms of bromine. C. A. M. Colour Reactions of Sesame Oil and Bile Acids with Various Sugars. C. Fleig. (BUZZ. SOC. Chim., 1908, 3, 99%999.)-Experiments were carried out in order to ascertain which sugars give the most sensitive reaction in the usual Baudouin test for sesame oil. I t was found that practically only three sugara- namely, laevulose, sucrose, and invert sugar-can be used ; other carbohydrates, such as rafinose, xylose, erabinose, galactose, mannose, dextrose, lactose, maltose, etc., yield but slight, if any, coloration (cf.ANALYST, 1904, 29, 290). I n the case of Pettenkofer's test for bile acids, the three sugars which were found to give the best reaction in the Baudouin test also gave the most intense colorations with bile acids ; the other sugars yielded fainter colorations, and the reaction took place more slowly. IT. P. s. Colour Reactions of Sesame Oil with Aromatic Aldehydes. C. Fleig. (BziZZ. SOC. Chinz., 1908, 3, 984-991.)-The furfural in the reagent recommended by Villavecchia and Fabris (ANALYST, 1894, 19, 47) for the detection of sesame oil, may be replaced by other aromatic aldehydes. Of the latter, p-hydrosybenzaldehyde, y-methoxybenzaldehyde, protocatechuic aldehyde, vanillin, piperonsldehyde, and cinnamaldehyde act equally as well as furfural ; then follow salicylaldehyde, benzaldehyde, o-nitrobenzaldehyde, and p-dirnethylaminobenzaldehyde.The least sensitive are 716-nitrobenzaldehyde, cuminaldehyde, and p-nitrobenzaldehyde. The substance in the oil which gives the coloration may be extracted from the oil by means of absolute alcohol, and the alcoholic solution then used for the test, w. P. s. Volumetric Estimation of Lactose by Means of Ammoniacal Copper Solution. Y. Shimidzu. (Bioclicm. Xeitsch., 1908, 13, 243-361.)-\Vhilst lactose cannot be accurately estimated by any of the volumetric methods when the sugar is titrated directly, the estimation becomes quite trustworthy if the migar is inverted previously. Using the modified Pavy's solution recommended by Kumsgawa and Suto, 0.0109 gram of lactose (after inversion) bas the same reducing power as 0.01 gram of dextrose.Lactose is completely inverted by heating from 0.25 t o I grani of the sugar with 100 C.C. of 10 per cent. sulphuric acid, or 5 per cent. hydrochloric acid, for one hour at a temperature of 100" C. The d-dextrose and d-galactose produced remain unchanged if the heating be continued for a further thirty minutes. The results obtained agree with those yielded by the gravimetric process for the estimation of lactose. w. P. s. Detection of L%vu!ose in the Presence of Other Carbohydrates. (BUZZ. SOC. Ckim., 1908, 3, 966-984.)-The tests proposed are based J. Pieraerts.THE ANALYST.48 1 on the fact that lizvulose reduces alkaline copper solutions much more readily than does any other sugar which occurs naturally. Whilst Fehling's solution cannot be used for differentiating the various reducing sugars, a modified Ost solution (250 grams of potassium carbonate, 100 grams of potassium hydrogen carbonate, and 1 7 5 grams of crystallised copper sulphate per litre) was found to answer the purpose. Levulose reduces this reagent in two and a half hours at the ordinary temperature, or in one hour at 35" C. ; other sugars are without action, but the pentoses show a reducing action after about four hours at the ordinary temperature, or in one hour at 35" C. A solution containing 12 grams of glycocoll, 6 grams of cupric hydroxide, and 50 grams of potassium carbonate per litre is also a very useful reagent for detecting lmulose ; it is reduced by a 5 per cent.solution of lmwlose in four hours at the ordinary temperature, but other sugars, including the pentoses, have no action. Lmulose may be detected in honey, fruits, sweets, marmalade, crude sugars, molasses, etc., by means of the above reagents. The solution used for the test should contain about 5 per cent. of total reducing sugar, of which about 20 per cent, should be levulose. w. P. s. Polarimetric Estimation of Starch. E. Ewers. (Chem. Zeit., 1908, 32, 996-997.)-For the valuation of raw materials for the manufacture of starch an estimation of insoluble matter is required, and this is not possible with Lintner's method (ANALYST, 1907, 32, 179).The author therefore prefers a method in which the starch is dissolved by means of dilute (about 1 per cent.) hydrochloric acid. Five grams of the finely-sieved material (or 10 grams of finely-rasped potato) arc: shaken with 25 C.C. of 1.124 per cent. (by weight) hydrochloric acid (or 0.4215 per cent. acid in the case of potatoes) in a 100 C.C. flask, the neck of which is subsequently washed free from particles with 25 C.C. of the same acid. The flask is next placed for exactly fifteen minutes in boiling water, and during the first three minutes is repeatedly shaken with a rotatory movement. Its contents are then diluted to about 90 C.C. with cold water, cooled to about 20" C., clarified with ammonium molybdate, made up to 100 c.c., filtered, and polarised.The results thus obtained agree well with those given by Lintner's method. For the estimation of the insoluble matter in starch or of starch in chocolate, etc., the method recommended is to macerate the substance for twenty-four holxrs with dilute hydrochloric acid or with water, and, if necessary, to invert the filtered solution of carbohydrates thus obtained (cf. ANALYST, 1906, 31, 25; 1908, 101). c. A. &!I. The Fat of Tonka Beans. Duyk. (Ann. de Chim. Anal. AppZ., 1908, 13, 391.)-The fat of the tonka bean (Coumarouna ezcelsa) is used in the preparation of certain kinds of confectionery, and is exported in considerable quantihies from Holland. The sample examined by the author was an orange-yellow wax-like mass with a characteristic odour of coumarin. The latter substance could be isolated by shaking the fat with it little boiling water, filtering the aqueous extract, and allowing the filtrate to stand. After a few hours an abundant deposit of white needle-shaped crystals (melting-point, 6 8 O to 6 9 C.) was obtained. Tho fat gave the following analytical values : Illelting-point, 28' C. ; specific gravity at 100" C., 0.888 ; butyro-482 THE ANALYST. refractometer reading, 47" ; critical temperature of solution (1 volume of fat, 2 volumes of absolute alcohol in an open tube), 32.5" C. ; acid value, 7 ; saponifica- tion value, 257 ; and Reichert-Meissl value (Leffmann and Beam's method), 5.4. The fat also contained a considerable proportion of volatile insoluble fatty acids. C. A. M.

ISSN:0003-2654    

DOI:10.1039/AN9083300476

出版商:RSC    

年代:1908

数据来源: RSC

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482 THE ANALYST. INORGANIC ANALYSIS. An Investigation of Fuller's Earth. (Chem. Rev. Fett- u. Hurx-Ind., 1908, 15, 253-255.)-Analyses of the minerals with which Fuller's earth may be associated lead to the conclusion that it is a decomposition product of hornblendes and augite, and not, like ordinary clay, of felspars. This view is supported by the fact that magnesia is invariably an important constituent of fuller's earth, in which it is as a rule present in much greater proportion than in ordinary clays. This is shown in t h e following table of analytical results given by different kinds of fuller's earth, the figures being collated from various sources, and calculated on the dry substance. Origin. Arkansas ... ... Ocala, Florida ... Gladsden, Florida . . , Norvay, Florida ...Decatur, Georgia ... Enid, Oklahoma (glazialite) ...} Custer, South Dakota ... ... Fairburn, South Dako ta... ... Nutfield, England (blue earth) ...} Nutfield, England ) (yellow earth) . . . J Reigate, England ... Woburn Sands, England (yellow earth) ... ... Woburn Sands'Eng- land (blue earth) } Silica. Per Cent. 64-38 39.66 67.31 59-02 72'00 50.36 57.00 68.23 52-81 6S.37 53.00 55'48 60.90 klnmina. Per Cent. 17.29 30.00 11 -07 11-88 10.76 33'38 17-37 14-93 6 -92 11.82 10.00 19.16 18'34 Water. Per Cent 6 *95 13.11 8.25 11'13 6.00 12-00 9 -50 6 *20 14.27 13'19 24-00 6 -75 4 -89 Ferric Oxide. Per Cent. 8.27 3.46 2-61 7.24 2-65 3-31 2.36 2.15 3-78 6.27 9.75 11.78 10'22 I Magnesia. I ?er Cent. I Per Cent. 1.91 0.87 2'60 6-48 3.34 - 3.00 2.93 7-40 6.17 0 5 0 3.10 2-36 0.70 3.32 3-24 4-36 - 3-03 0.87 2.27 2.09 1-25 3-71 1 -52 Alkalies.?er Cent, 1 '83 0.45 1.01 - - 0.88 __ - 1 -74 1.84 - - 1'72 Other Elements. Per Cent. - P,O,, 6-00 Oi*,qaiiic mat- ter, 3-90 no,, 1.37 - - - TiO,, trace Organic mat- ter, trace Volatile snh- stances, 5 '8 5 Volatile sub- stances, 5 -85 - P,O,, 0.27 SO,. 0.05 NaC1, 0.05 P,O,, 0.14 SO,, 0.07 N'aC1, 0'14 - - - C. A. M.THE ANALYST, 483 Volumetric Estimation of Potassium Ferrocyanide. H. Bollenbach. (Zeits. anal. Chem., 1908, 47, 687-690.)-The solution of potassium ferrocyanide is strongly acidified with dilute sulphuric acid, and standard potassium permanganate solution added until a decided red colour is produced. After adding a few drops of a solution of ferric sulphate, the excess of permanganate is estimated by adding & potassium ferrocyanide solution until a permanent greenish-blue colour is produced ; the addition of 1 drop of the permanganate solution should destroy this colour.The method is accurate to within 1 per cent. of the ferrocyanide present. A. G. L. Suitability of Commercial Ammonium Swlphate as Manure. F. J. Lloyd and U. Bonelli. (Chem. Trade Journ., 1908, 43, 362.)--Although commercial am- monium sulphate now rarely contains any appreciable quantity of thiocyanates, many samples are contaminated with organic compounds (coal-tar derivatives) which in the opinion of the author have an injurious action on plant life. In order to distinguish between these and the innocuous organic matter present in “ bone sulphate” the authors apply tho following test : One gram of the sample is dissolved in 5 C.C.of water and strong ammonia added. A violet coloration is produced in the presence of the undesirable organic compounds, no such colour being obtained with 6‘ bone sulphate ” or pure 66 gas sulphate.” Since these organic hubstances tend to obscure the usual reaction for thiocyanates, the best method of applying the test is to dry 5 grams of the sample, after moistening with strong ammonia, in the water-oven, grind it in a mortar with 5 C.C. of alcohol and filter, and test the clear filtrate with ferric chloride. A. R. T. Volumetric Estimation of Phosphoric Acid in Fertilisers. R. Williams. (Chem. Engineer, 1908, 8, 97-99.)-The American official volumetric molybdate method for the determination of phosphoric acid in acid phosphates and commercial fertilisers (Bull.No. 107, Bureau of Chemistry, U.S. Department of dgricultu;?.e) is open to serious objections, among which may be mentioned-(1) the erroneous results due either to the presence of sulphates in the material or to the use of sulphuric acid as a solvent, sulphates causing a precipitation of molybdic acid in excess of the thgoretical amount necessary to combine with the phosphoric acid present; and (2) the presence of arsenic in the fertiliser. The author therefore first separates the total phosphate by precipitating an aliquot portion of the acid solution of the material (equal to from 0.1 to 0.4 gram sample), containing as little excess of acid as possible, by the addition of 1 C.C. of mixed ferric and calcium chlorides (10 per cent.of each in solution), and sufficient ammonia to render the solution slightly alkaline. One hundred and fifty C.C. of boiling water are next added and the settled liquid filtered, the precipitate washed once with hot water, and then dissolved in 100 to 125 C.C. of hot dilute nitric acid (70 C.C. strong acid in 1 litre). The solution is nearly neutralised with ammonia, precipitated with 30 to 35 C.C. of the molybdate solution added to the rotated hot liquid, and the process then carried out as directed in the official method (loc. cit.). A. R. T.484 THE ANALYST. Analysis of a Mixture of Neutral Sulphides, Acid Sulphides, Poly- sulphides, and Hydrosulphites. F. Dhuique-Mayer. (Rev. gher. Chin&. pure appl., 1908, 11, 273-274; through Chem. Zed. Rep., 1908, 32, 485.)-Ten C.C. of the 6OlUtiOn are diluted to 100 C.C. with water. Ten C.C. of this diluted solution are titrated with sulphuric acid, using phenolphthalein as indicator. The value obtained (A C.C. & solution) corresponds to the neutral sulphides present. The same solution is then titrated with iodine solution and starch, giving a value I. After decolorising the solution by adding a few drops of the diluted origintll liquid, sodium hydroxide is added until the solution becomes pink, giving a value R, which corresponds to the total acid sulphide formed in the solution. Another 10 C.C. of the original solution is diluted, treated with 2 grams of lead carbonate, filtered, and titrated with iodine solution and starch, the value H obtained corresponding to the hydrosulphite present. The acid sulphide originally present in the liquid equals (R - A) ; the polysulphide corresponds to (I - 2R - H). A. G. L.

ISSN:0003-2654    

DOI:10.1039/AN9083300482

出版商:RSC    

年代:1908

数据来源: RSC

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484 THE ANALYST. APPARATUS, ETC. Modiflcation of' Hufner's Method for the Volumetric Estimation of Nitrogen. V. v. Cordier. (Zeits. anal. Cheni., 1908, 47, 682-687.)-Nitrogen in such substances as guanidine picrate and carbonate, urea nitrate, etc., which though only sparingly soluble, are violently acted on by sodium hypobromita solution, can be volumetrically estimated in the modified Victor Meyer apparatus shown. The bulb a contains 40 to 50 C.C. of the hypobromite solution, into which the substance, contained in a small glass bulb, is allowed to drop after equilibrium of temperature has been established in the apparatus ; when the evolution of nitrogen begins to slacken, fresh hypobromite solution is introduced from the bulb b, which holds 30 to 40 c.c., without altering the volume inside the vessel.The whole apparatus may be immersed in water, if necessary. Evolution of nitrogen is com- plete in one hour. A. G. L. Primus Burner for Mine Laboratories. R. Storen. (Zeits. anal. Chem., 1908, 47, 695-696.)- For heating hot-plates and sand-baths, a Barthel Primus burner, burning benzine, is recommended, The apparatus is modified by making the burner itself of nickel instead of copper, and separating it from the benzine container by a metal tube of such length that the latter remains cold. A. G. L.THE ANALYST. 485 Compound Gas-Pipette. H. Fleissner-Przib- ram. (Chem. Zeit., 1908,32, 770.)-The compound gas- pipette shown is provided with a short through which the bulbs a and b are filled. pipette is filled, the tubef is stoppered by a short piece Steam Distillation Tube.H. Stoltzenberg. (Chem. Zeit., 1908, 32, 770.)- The tube through which steam is led into the liquid to be distilled is closed at the 3 An Improved Water-Oven. A. P. Sy. (Chem. EngiTzear, 1908, 8, 100-101.) - -This oven contains an improved device for a cone t an t -level water- supply, consist in g of an elbow-tube of sheet copper, about 13 mm. in diameter, the short arm being soldered to the oven near the base. At a height to which the oven is to be kept filled with water (about half full), a somewhat smaller side-tube is soldered on to the elbow-tube, and the whole held by a copper strap soldered to the oven and the tube a little below the side-tube of the latter. Water is supplied to the oven through a bent glass tube, one 6rtn of which hangs loosely in the elbow-tube just below the side-tube, the latter being connected to the waste-pipe.The burner, which is attached to the legs of the oven at a suitable height, and has an air-regulator, is of rectangular shape, the two long sides containing numerous small jets. A special feature of the oven is the V-shaped bottom of the inner jacket, which formation allows of the easy escape of air and steam during boiling, and thus prevents the bumping and jarring common to ovens of the ordinary type. A. R. T. Apparatus for Extracting Substances by Means of Hot Ether. W. Kulka. (Biochem. Zeitsch., 1908, 13, 134-137.)-The piece of apparatus described consists of an outer glass cylinder, like that of the ordinary Soxhlet extractor. An inner cylinder, provided with a siphon, which discharges into the extraction flask attached to the lower end of the outer cylinder, is fitted inside the latter.The substance to be extracted is placed in this inner cylinder, and the ether vapours, passing upwards in the space between the two cylinders, are condensed in a condenser situated at the486 THE ANALYST. top of the appsratus, and fall into the inner cylinder. The ether thus collected is heated by the hot vapours, and the substance is extracted oontinuously at a tern- perature approaching that of boiling ether. w. P. s. Reaction Turbine. A. Gawalowski. (Zeits. anal. Chern., 1908, 47, 697.)- - The apparatus consists of a long-stemmed glass funnel, S, terminating in two horizontal tubes, bent as shown. The stem of the funnel is surrounded by the sealed glass globe B, containing air, whilst a small glass globe, Q, containing mercury, is attached below the horizontal tubes. When placed in a liquid, the apparatus floats like a hydro- meter; if a second liquid be then poured into the funnel, it flows out by the horizontal tubes, rotating the apparatus and mixing the two liquids in doing so. A. G. L.

ISSN:0003-2654    

DOI:10.1039/AN9083300484

出版商:RSC    

年代:1908

数据来源: RSC