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THE ANALYST. JANUARY, 1904. PROCEEDINGS OF THE SOCIETY OF PUBLIC ANALYSTS. THE monthly meeting of the Society was held on Wednesday evening, December 2, in the Chemical Society’s Rooms, Burlington House, The President, Mr. Thomas Fairley, occupied the chair. The minutes of the previous meeting were read and confirmed. Mr. John Hughes and Mr. W. P. Skertchly were appointed to act as auditors of the Society’s accounts for the year 1903. certificates of proposal for election to membership in favour of Messrs. F. Hud- son-Cox, N. van Laer, J. S. Maclaurin, D.Sc., and T. R. Nightscales, were read for the second time; and certificates in favour of Messrs. Frank Eustace King, B.Sc. (Lond.), A.I.C., ‘‘ Woodbury,” Polworth Road, Streatham, assistant to Dr. Bernard Dyer ; and William Herbert Simmons, ( ( Oakleigh,” Stoke Newington Common, N., assistant chemist to the Vinolia Company, Ltd., were read for the first time. Messrs. H. Harman and C. J. Waterfall were elected members of the Society. The following papers were read: ‘( The Characteristics of some Almond and Allied Oils,” by J. Lewkowitsch, M.A., Ph.D. ; ‘: Note on the Examination of Sperm Oil,” by L. Myddelton Nash; and “The Estimation of Aldehydes and Ketones in Essential Oils,” by Herbert E. Burgess. The President showed some photographs taken by and illustrating the pene- trative power of the rays emitted by radium.

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年代:1904

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2 i?): THE ANALYST. Hexabromides from Glycerides, per Cent. DIFFERENTIATION OF LINSEED OIL FROM BOILED OILS. BY DR. J. LEWKOWITSCH, F.I.C. (Read at the Neeting, November 4, 1903.) IN a paper read before the Society of Chemical Industry, 1903 (p. 595), I mentioned several experiments made with the hexabromide test on linseed oil and '' boiled " oils derived from it. I am now in a position to submit the following results, which seem to prove that this test may be used for differentiating the drying oils from the boiled oils. The term " boiled " oils includes oils boiled with driers as also oils prepared without driers. I Name. ~~ 1. Linseed oil ... ... ... ... ... 2. Pale boiled oil ... ... .*. I . . 3. Double boiled oil ... ... ... 4. Linseed oil, heated to 600O.F. ... 5.Linseed oil, blown at 120" C. for ten hours 6. Ozonized oil ... ... *.. ..- 7. Quick-drying oil (extracted with hydro- 8. Best siccative oil (extracted with hydro- chloric acid) ... ... ... ... chloric acid) ... ... f . . ... 9. '' Thin " lithographic varnish ... ... 10. '' Medium " lithographic varnish 11. '' Thick " lithographic varnish ... ... 12. Burnt lithographic varnish ... ... 13. Lithographic varnish ... ... ... 14. Lithographic varnish ... ... ... 15. Lithographic varnish ... ... ... 16. Safflower oil (raw) ... ... ... 17. Double-boiled safflower oii" ... ... ... Specific Gravity. 0.9308 0.9429 0.9449 0,9354 0-9460 0.9310 0.9483 0.9388 0-9691 0.9693 0.9747 0.9720 0.9676 0-97034 0.9 2461 0,9447 -- - 186.4 171.0 169.96 176-3 166.6 . 180.1 169.7 171.2 125.3 121-9 118.5 102.69 109.4 107-7 126.5 146.46 141.8 24.17 20.97 13-03 8-44 23.16 36.26-36.34 30.19 25.73 2.00 0.95 none none 0-24 0-17 none none - The oils mentioned under Nos. 6, 7, and 3, are remarkable on account of the high yield of hexabromides. Unfortunately, the raw linseed oil from which they were prepared was not examined. It was a Baltic linseed oil of fair quality, and I have no reason to assume that its iodine value would have exceeded 185. At the time I examined the ozone process by which the three oils were prepared, the iodine values of these oils struck me as being exceptionally high. The fact that the drying nnwer nf the nils was verv eood does not sneak in favour of the assumotion which is frequently made-namely, that the oxygen absorption of oils stands in direct ratio to the iodine value. Of course, this is also evidenced by the fact that fish and cod- large amounts of oxygen.

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年代:1904

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THE ANALYST. 3 NOTE ON THE EXAMINATION O F SPERM OIL. BY L. MYDDELTON NASH, F.I.C. (Rsad at the Meeting, December 2, 1903.) SPERM oil on saponification yields about 40 per cent. of ether residue, consisting of mixed alcohols, which are completely soluble in absolute alcohol. Mineral oil, as is well known, is practically insoluble therein. But the fact that the unsaponifiable matter from a sample of sperm oil is soluble in alcohol is no proof whatever that the sample is free from mineral oil, as sperm alcohols give ethyl alcohol the property of dissolving mineral oil freely. If rectified spirit be used instead of absolute alcohol, the amount of mineral oil dissolved is very much less. The following table shows the proportions in which mineral oil is soluble in mixtures of sperm alcohols with absolute alcohol and with rectified spirit.Absolute Alcohol, Volumes taken. Sperm Alcohols, Volumes added. Temperature, Fahrenheit. Mineral Oil: Volumes dissolved, using Absolute Alcohol. Mineral Oil, dissolved, using Rectified Spirit, S.G. 0.8345. 100 100 100 100 100 100 0 4 10 40 40 100 70 70 70 $0 100 70 2 4 8 100 175 any amount trace trace 1 18 20 100 The alcohol was measured in a graduated cylinder, the measured sperm alcohols added, and then mineral oil, until the solution, which was at first;, o h r , became turbid on shaking. The mineral oil used was American lubricating oil, specific gravbty 0.905. DISCUSSION. Dr. LEWKOWITSCH said that this paper exemplified the necessity for avoiding the assumption that solubilities determined for one substance would also hold good if another substance was introduced into the solution. A case in which such a mistaken assumption was often made was the extraction with ether of the lead salts of liquid fatty acids in the presence of solid fatty acids, with a view to a quantitative separation.Of course, the lead salts of stearic and other solid fatty acids were practically insoluble in ether, but if the amount of oleic or other less saturated acid were considerable, the dissolved lead salt would exercise in its turn a solvent action on the lead salts of the solid fatty acids. I t is desirable, therefore, that such a test as that described in this paper should not be relied upon alone, but that the unsaponifiable matter shbuld be further differentiated by treatment with acetic anhydride.4 THE ANALYST.Mr. ALLEN said that evidently from the author’s observations it was undesirable to use absolute alcohol, or to use too strong a solution of the sperm alcohol. Of course, the separation could only be regarded as a preliminary one, and, as Dr. Lewkowitsch had pointed out, an absolute differentiation could only be arrived at by acetylating the alcohols. At the same time, there were cases in which that was not possible or desirable, and it was therefore well to know the exact conditions under which such separation as might be possible by alcohol could be best effected. It was frequently necessary to make some separation, even if only rough, of mineral oil from these higher alcohols, and the condition which had been pointed out by the author was one which it was very important to bear in mind. He (Mr. Allen) had been among the early workers on the subject of sperm alcohol, and among the first, he believed, to point out that sperm oil was a liquid wax, and that it contained as much as 40 per cent. of unsaponifiable matter, which unsaponifiable matter consisted of solid higher alcohols, apparently not of the ethylic series. solubility test as final, but the point was one which he had not seen mentioned before, and he thought it worth notice. Many people, he believed, did use absolute alcohol; in fact, he himself did so. In that case mineral oil would not show at all, as it was completely soluble. Mr. NASH agreed with Dr. Lewkowitsch that no one would thipk of taking

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4 THE ANALYST. ABSTRACTS OF PAPERS PUBLISHED IN OTHER 3OU RN ALS. FOODS AND DRUGS ANALYSIS. Detection and Estimation of Fusel-Oil in Rectified Spirits. A. Homarowsky, (Chem. Zeit., 1903, xxvii., 1086.)-Although furfurol is a delicate reagent for the detection of isoamyl alcohol, the test which the author has previously described (ANALYST, 1903, xxviii., 293) has proved not to be trustworthy in practice, since certain commercial spirits appear to contain substances that interfere with the colour. Salicylic aldehyde should therefore be employed, but care must be taken that all tests are carried out under strictly similar conditions, both as regards quantities of reagents added and amount of agitation. I t has been found that the same amount of isoamyl alcohol always develops the same depth of colour, and that a difference of 0*001 per cent.in the proportion present is quite noticeable. Should the quantity be extremely minute, another 1 C.C. of the salicylic aldehyde solution may be added. It has also been found that the other constituents of fusel-oil yield identical colours, but in different intensities ; the following quantities being identical in their behaviour to the test : 0.003 per cent. of isosmyl, 0*001 per cent. of isobutyl, and 0.009 per cent. of 12-propyl alcohol. This, however, does not diminish the value of the reaction, because the amount of these other alcohols in fuse1 oil is so small. The test may be rendered quantitative by colorimetry, but it is first necessaryTHE ANALYST. 5 to know whether the sample contains acetaldehyde, for this makes the colours stronger.Several sets of shndard alcohols prepared from pure spirit are required. The first contains isoamyl alcohol only, in amounts of 0.001, 0.003, 0,007, and 0.009 per cent. A second contains 0.001 per cent. of isoamyl alcohol together with 0*0005, 0.001, 0-0015, 0.002, 0.0025, and 0.003 per cent. of acetaldehyde. A third, fourth, and fifth series similarly contains the same increasing proportions of acetal- dehyde mixed with the higher quantities of isoamyl alcohol given in series 1. These suffice for all ordinary (Russian) purposes. The amount of acetaldehyde in the sample having been determined (if any), two or more tubes are charged, one with 10 C.C. of the specimen under examination, the others with the same volume of the most likely standards.To these are added 25 or 30 C.C. of the salicylic anhydride solution mentioned in the former article, and 20 C.C. of strong sulphuric acid are run down the tube so as to sink through the liquids. When all the tubes are ready, they are shaken simultaneously, and the colours are compared when they have become cold. Several quantitative tests quoted by the author show a satisfactory agreement with the Rose process, while he mentions that some specimens, which required a month for the completion of the former method, were examined in a day by colorimetry . F. H. L. The Estimation of Formaldehyde in Milk. Bernard H. Smith. (Journ. Amer. Chem. Soc., xxv,, 1036.)-Following Leonard and Smith’s suggestion (ANALYST, xxii., 5) to add a few drops of sulphuric acid to the milk before distilling it in order t o determine the formaldehyde it contains the author shows that the best results are obtained by adding to 100 C.C.milk 1 C.C. dilute (1 : 3) sulphuric acid. The first 20 C.C. distilled over will then contain practically one-third of the total formaldehyde present in the milk. The quantity of formaldehyde recovered in this way remains almost constant, even when the milk is kept for forty-eight hours, provided only that it is stored in a cool place. In the actual distillation the use of a Kjeldahl flask and of a round, flat evaporating burner is to be recommended. A. G. L. A Comparative Study of Methods of determining Formaldehyde. Bernard H. Smith. (Jouriz. Amer. Chern. Soc., xxv., 1028).--Having made a comparative study of the different methods, the author comes to the conclusion that the Blank and Finkenbeiner method (Berichte, xxxi., 2979) is very satisfactory for strong solu- tions of formaldehyde ; that the Legler method (Berichte, xvi., 1333) gives somewhat lower, fairly satisfactory results ; that the gravimetric hexamethylene and the ani1ip.e volumetric methods (Pharm.Zeitg., xl., 611) are practically worthless ; and that the iodometric (Zeits. anal. Chem., xxxix., SO), and especially the potassium cyanide (Zeits. anul. Chem., xxxvi., 18), methods give good results for dilute solutions. By the last method it is possible to determine with accuracy 1 pazt of formaldehyde in 100,000. The essential feature of the method is that formaldehyde forms an addition product with potassium cyanide, the excess of which is then tritrated with silver6 nitrate and ammonium must be mixed with the THE ANALYST.thiocyanate, and consequently the formaldehyde solution potassium cyanide solution before adding the silver nitrate. A. G. L. Detection of Yolk of Egg in Margarine. G. Fendler. (Zeit. ftir Untersuch. cler Nahr. und Gewussmittel, 1903, vi., 977-980.)-A method is given in which the margarine is sxtracted with a solution of common salt. This dissolves the yolk of egg, and the solution may be tested by adding hydrochloric acid, by extracting the colouring matter with ether, or by dialysis. Three hundred grammes of margarine are melted at a temperature of 50" C., 150 C.C. of 2 per cent. sodium chloride solution are added, and the mixture kept at 50" C.for two hours. I t is then well cooled, and the aqueous solution separated and repeatedly passed through a filter until the filtrate is as clear as possible. A perfectly clear and colourless filtrate, however, indicates the absence of yolk of egg. On adding an equal bulk of concentrated hydrochloric acid to a filtrate which is persistently turbid, a clear solution is obtained, again becoming turbid on heating should yolk of egg be present. A further test is to acidify 10 C.C. of the salt solution with 1 C.C. of 1 per cent. sulphuric acid solution, heat the mixture to boiling for a short time, cool, and shake with 2 C.C. of ether. The latter dissolves the colouring matters of the yolk of egg should it be present, and the ethereal layer is coloured a faint yellow.Fifty C.C. of the filtered salt solution may be placed in a moist dialyser surrounded by water. If, after five or six hours, the solution in the dialyser becomes markedly turbid, but clears again on the addition of sodium chloride, yolk of egg is present. w. P. s. Occurrence of Arsenic in Hens' Eggs. G. Bertrand. (Corn@. rend., 1903, cxxxvi., 1083-1085 ; through Zed. fiir Untersuclz. der Nahr. ziizd Genzissmittel, 1903, vi., 986.)-Hens' eggs were found to contain, on the average, &a milligramme of arsenic. All parts of the egg contained it. About half of the total quantity was found in the yolk, and the smallest portion in the white. The outside membrane, in spite of its small weight, often contained as much as, or more than, the white.No arsenic was detected in the shells. w. P. s. The Composition of Panna Rhizome. A. Altan. (Journ. Pharrn. Chim., 1903, xviii., 497-502.)-The panna (Aspidzzm athamuntieurn) is a cryptogamous plant indigenous to Caffraria, where the natives use its rhizome as an anthelmintic agent. A sample of the dried commercial product examined by the author contained 8.65 per cent. of moisture, and had the following composition, calculated on the dry substance : Fat, 3.36 ; resins, 8.50 ; tannin, 2.75 ; colouring matters, 2-12 ; proteids, 1.12 ; starches, 9.96 ; cellulose and woody fibre, 64.1 ; and mineral matter, 8.12-per cent. The fatty oil was insoluble in alcohol, but readily soluble in ether and chloroform. It melted at 11.5" C., solidified at 2.3" C., and had a specific gravity of 0-917 at 1 5 O C.C. A. M.THE ANALYST. 7 The Characteristics of Gum Chicle. F. 0. Taylor. (Arner. Jozcrn. Pharm., 1903, lxxv., 513-515.)-The following results were obtained in the analysis of a sample sold as purified gum : Ash, 0.2 ; moisture, 2.2 ; substances soluble in chloroform, 82.7, and substances soluble in benzene, 84.7 per cent. ; esters, none ; acid value, 52.0 ; saponification value, 52.0. Characteristies of Sparteine. C. Moureu and A. Valeur. (Journ. Pharrn. Chim., 1903, xviii., 502-508.)-Sparteine distils at 188" C. (corr.) under a pressure of 18.5 millimetres as a thick, colourless oil, with a very bitter taste and an odour recalling that of piperidine. Under a pressure of 754 millimetres it can be distilled without decomposition at 325" C.(corr.) in a current of dry hydrogen. Its optical rotation when dissolved in absolute alcohol is [aID = - 16" 42'. Its solubility in water at 22" C. is only 0.304 gramme in 100 grammes, but it dissolves readily in alcohol, ether, and benzene. It has a strongly alkaline reaction, and is capable of neutralizing strong acids. When titrated with helianthin as indicator, a molecule of sparteine neutralizes two molecules of hydrochloric acid, but with turmeric or phenolphthalein as indicator only 1 niolecule of acid is neutralized. Hence the authors conclude that sparteine is a diamine. From their experiments they also affirm that Ahrens' dihydrosparteine does not exist, and show that sparteine offers very great resistance to the action of reducing agents.C. A. M. Assay of the Crude Alkaloid obtained from Different Kinds of Coca Leaves. W. Garsed. (Pharm. Journ., 1903, lxxi., 784-791.)-Two distinct pro- cesses are described. In the first the crude alkaloid is dissolved in dilute sulphuric acid and treated with potassium permanganate. The unoxidized alkaloid is re- extracted and weighed, the loss in weight giving the amount of cinnamyl-cocaine present. The re-extracted alkaloid is then subjected to alkaline hydrolysis, and the a-truxillic and beneoic acids separated by taking advantage of the insolubility of the former in water. According to the second mer;hod, the crude alkaloid is at once subjected to alkaline hydrolysis, the cinnamic acid determined by the bromination method, and the a-truxillic acid by its insolubility in water.The truxilline and cinnamyl-cocaine are then calculated, and the amount of cocaine found by difference. The details of the two methods are as follows : Process 1.-A weighed quantity of the alkaloid is dissolved in dilute sulphuric acid, and 4 potassium permanganate solution is run in, about 1 C.C. at a time, until the reduction is apparently finished. The whole is then made alkaline with ammonia and thoroughly extracted with ether. After evaporating the ether, the residue is dried and weighed. The weight gives the cocaine and truxilline, and the difference cinnamyl-cocaine. This residue is gently heated with an excess of & alcoholic potash solution and 20 C.C. of water for thirty minutes under ~t reflux condenser. A slight excess of standard acid is then added, and the whole diluted .so as to contain 1 part of total mixed acids in 500.The insoluble a-truxillic acid is collected on a filter, washed twice with 5 C.C. of water, dissolved in hot alcohol, and the solution8 THE ANALYST. Process 1. Process 2. Process 1. Per Cent. , Per cent. I Per Cent. 23.1 , 13.4 I 51.0 (by difference) - ._ ~ ~ - ~ - - _ _ _ _ 18.2 , 17.8 I 8.1 52.0 ~ 68.8 37-0 93.3 ' 100-0 96.1 --- ---- titrated, using phenolphthalein as indicator, or it may be dried and weighed as a-truxillic acid. This multiplied by 2.22 gives the quantity of truxilline. Process 2.-A weighed quantity of the mixed alkaloids is heated with alcoholic potash solution as above described. The mixture is then rendered just acid, and an excess of a standardized solution of bromine containing potassium bromide is added.After agitating, potassium iodide is added, and the iodine liberated by the excess of bromine titrated. Cinnamic acid absorbs about 127 per cent. of its weight of bromine, and when multiplied by 2.22 corresponds to cinnamyl-cocaine ; benzoic and a-truxillic acids have no absorption. The solution of bromine should be about & normal. The mixed alkaloids from two varieties of coca leaves gave the following figures : The insoluble a-truxillic acid is then separated as before described. - Process 2. Per Cent. 9.3 38.0 52.7 (by difference) 100.0 -- Truxilline . . . ... Cinnamyl-cocaine . . . Cocaine ... ... Total ... ... Both processes give good results as far as truxilline is concerned, but as it is certain that cocaine and truxilline are practically unaffected during the oxidation of the cinnamyl-cocaine, preference must be given to the permanganate process.w. P. s. Determination of Aldehydes in Oil of Lemon. Berte. (Chemist and Druggist, 1903, lxiii. , 753.)-In the process describod, potassium hydrogen sulphite, instead of the sodium salt, is used to '' fix " the aldehydes, the volume of the remainder of the oil being measured at the end of the operation. Five C.C. of the oil of lemon are measured into a fractional distillation flask of about 100 C.C. capacity. A graduated tube is ground into the neck of this flask, whilst the side-tube is bent upwards and connected by a piece of tubing to a funnel. Twenty- five C.C. of a saturated solution of potassium hydrogen sulphite, containing a slight excess of sulphurous acid, are introduced, and the contents of the flask are heated to about 50" C.for ten minutes. After cooling, the heating is repeated for five minutes. When completely cold, water is introduced through the funnel and side-tube, so as to bring the layer of oil into the graduated tube. Little drops of oil adhering to the sides of the flask may be caused to rise by shaking and tapping the flask. After the layer of oil has become clear, its volume is read off, the differencze between this and 5 C.C. corresponding to the volume of the aldehydes fixed by the potassium hydrogen sulphite. The presence of oil of turpentine causes the aqueous portion to remain more orTHE ANALYST. 9 less milky even after twelve hours. When both oil of orange and turpentine are present in oil of lemon, a flocculent yellow precipitate is formed, which collects at the surface of the terpene. The volume of the precipitate roughly indicates the amount of oil of orange present. No visible precipitate is formed unless the oil of lemon con- tains at least 2 per cent. of oil of orange. w. P. s. Tea Cigarettes. I?. Netolitzky. (Zeit. fiir Untersuch. der Nahr. u"rd Geizzbss- mittel, 1903, vi., 982-985.)-A habit of smoking green tea in the form of cigarettes having been said to have arisen, the author gives the results of investigations carried out with a view to determining the composition of the smoke produced by these cigarettes. The' cigarettes were smoked by means of an aspirator, and the smoke,. etc., suitsbly collected. It was found that about 75 per cent. of the theine contained in the tea sublimed unaltered in the smoke. The latter aleo contained hydrogen sulphide, ammonia, carbon dioxide, and ethereal oils. These varied in amount, as did the theine, according to the rapidity and other conditions of the smoking of the cigarettes. w. P. s.

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DOI:10.1039/AN9042900004

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年代:1904

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THE ANALYST. 9 ORGANIC ANALYSIS. Simplification of Zeisel's Method of Methoxyl and Ethoxgl Determinations. W. H. Perkin. (Proceedings Chem. Soc., 1903, xix., 239.) -The following arrange- ments of the apparatus used in this process are dascribed, the results obtained being very good in the case of the methoxyl group, but a trifle too low with the ethoxyl group. A long-necked distilling flask was employed without any other condensing apparatus, the tube for the current of carbon dioxide being passed down the neck to within a short distance of the hydriodic acid. As long as the temperature of the glycerol bath was so adjusted that no acid distilled into the delivery-tube, no appre- ciable quantity of hydriodic acid passed into the silver nitrate flasks. The acid used boiled at 126" C., and had a specific gravity of 1.68.To prevent the silver nitrate solution from being sucked back into the distilling flask, two small flasks were used as usual; but the tube conducting the carbon dioxide and methyl iodide vapour, instead of passing into the silver nitrate solution, was kept some distance above its surface. The flasks were connected by a syphon tube, one arm of which reached within a short distance of the solution in the first flask, whilst the other arm dipped a little below the surface in the second. The methyl iodide was thus absorbed by the surface of the silver solution, and any escaping caught by the second quantity. If any drawing back took place, some of the solution passed into the first flask, and as soon as the pressure increased was forced back again into the second flask.w. P. s.10 THE ANALYST. New Volatile Oils. (Schimnel and Co.'s Report, October, 1903 ; through Pharm. Journ., 1903, lxxi., 614.)-Apopinol Oil.-This oil is manufactured in Central and North-East Formosa, and is believed to be obtained from a lauraceous tree. It bears some resemblance to camphor oil, and contains eugenol, safrol, cineol, and dipentene. Oil of Magnolia Kobus (D.C.)-A Japaneseoil, which is distilled from the fresh leaves and twigs of the tree. It contains a con- siderable quantity of safrol and a small amount of citral. The specific gravity is 0-9642 ; rotation, - 1" 6' ; acid number, 1.5 ; and ester number, 0.87. It is soluble in 1 to 2 volumes of 80 per cent. alcohol. Oil of Artemisia Vulgaris (Lim.)-This oil is known in Japan as '( Yomugi." It is of a clear green colour, possesses a strong odour of cineol, and has a specific gravity of 0.9101 ; rotation, - 13' 16' ; 'acid number, 1.56 ; and ester number, 29.86.Even in absolute alcohol the oil is not perfectly soluble, the solution showing an opalescence. Oil of Acacia Bavenia (Hook. and Arne)-A specimen was found to contain about 50 per cent. of phenols, chiefly eugenol, 8 per cent. of methyl salicylate, benzyl alcohol, geraniol, anisic aldehyde, eugenol methyl ether, and probably linalool decyl- aldehyde and ionone. Oil of Psoralia Bitunainosa (L.)--About 0.048 per cent. of oil is obtained from the leaves. It has a bituminous odour, is semi-solid at ordinary temperatures, and containa lauric acid.The specific gravity is 0*8988 at 25" C. ; the acid number, 57.18 ; and the ester number, 12.25. The plant grows in the Riviera. Oil of Inula Viscosa (Desf.)-The plant yields 0.062 per cent. of dark brown oil, from which a good deal of paraffin separates at ordinary temperatures. A fluid fatty acid is also present. The oil has a specific gravity of 1.006 ; acid number, 164.63 ; and ester number, 15.77. Oil of Helichrysum Angz,&ifolium (Sweet.)-A yellowish-brown oil having a specific gravity of 0.9182 ; rotation, + 0" 40 ; acid number, 14.4 ; and ester number, 118.16. I t forms a clear solution with 80 per cent. alcohol, from which after a time a paraffin having a melting-point of 67" C. separates out. This, like the preceding oil, comes from the Riviera.Its specific gravity is 0.9786 ; rotation, + 1" 40' ; acid number, 15.7 ; and ester number, 37-56, at a temperature of 20" to 25" C. Oil of Cistus XalvizfoZius.-The leaves of the plant yield 0.024 per cent. of oil, having a specific gravity of 0.9736 ; rotation, 1 7 O 2 0 ; and an ester number, 22-73. The oil is yellowish-green in colour, has an odour of ambergris, and deposits a The yield is about 0.45 per cent. Oil of Cistzu M0nspelieizsis.--The oil has an odour of ambergris. A paraffin melting at 64' C. is present in the oil. paraffin. w. P. s. A Colour Reaction of Chloroform, Bromoform, and Iodoform. Dupouy, (Bull. Xoc. Pharm., Bordeaux, 1903; through Ann. Chim. anal., 1903, viii., 426.)- A characteristic coloration is obtained on warming with sulphuric acid the product of the reaction of thymol and chloroform in the presence of potassium hydroxide.One drop of chloroform boiled with 0.5 C.C. of a 5 per cent. alcoholic solution of thymolTHE ANALYST. 11 and B fragment of potassium hydroxide gives a yellow colour, changing to red. On now adding 1 C.C. of sulphuric acid, and again applying heat, the liquid becomes intense violet, and dissolved in acetic acid shows a spectrum resembling that of oxyhaemoglobin, with the difference that the two absorption bands in the green are nearer to the red part of the spectrum. The colouring matter in aqueous solution gives a spectrum with one absorption band between the D line and the red. I n the absence of chloroform, the addition of sulphuric acid, thymol, and potassium hydroxide, gives a slight bluish coloration without spectroscopic bands.In using this test in toxicological work, Vitali’s method of removing the chloroform by means of a current of hydrogen is recommended. A similar reaction is given by bromoform, and with much more difficulty by iodoform. C. A. M. A Study in Raffinose Determinations, David L. DavolI, jun. (Jozirn. A?ner. Chem. SOC., xxv., 1019.)-To compare the accuracy of different methods for the determination of raffinose and sucrose in molasses the author has made experiments with an artificially-prepared solution containing 11.4612 grammes pure cane-sugar and 0.814 gramme raffinose per 100 C.C. The methods used were : (1) The strict Clerget method, without the use of any clarifying agent; (2) the same method, using 3 grammes of Merck’s purest animal charcoal, with five minutes’ shaking; (3) the Lindet-Courtoune method, adding 2 C.C. hydrochloric acid every four minutes, and heating thirty minutes in all; (4) the Herles method, using 10-6 C.C.lead nitrate solution and one-half equivalent sodium hydroxide ; (5) the author’s own modifica- tion of the Clerget method, which consists in allowing 1 gramme powdered zinc to act for three or four minutes at 69” C. after complete inversion has been effected by the Clerget method, 50 C.C. of the original solution being taken for inversion in all the methods except in the Lindet-Courtoune, where the prescribe3 20 C.C. were used. The author finds that his own modification gives results agreeing very closely with those given by the strict Clerget method.The use of charcoal with the Clerget method results in a very considerable increase in the levo-rotation, and causes a very notable variation in sucrose and raffinose. The Lindet-Courtoune method gives better results, but still is unsatisfactory, besides being tedious. Results obtained by the Herles method are rather better than those obtained by the Lindet- Courtoune method. A. G. L. Detection of the Blood of Different Animals. A. Partheil. (Zed. fur Untersuch. der Nahr. m d Ge?zuss?nittel, 1903, vi., 923-927.)-When an animal is inoculated with the defibrinated blood of another animal, the blood-serum of the animal obtains the property of forming a precipitate with the serum of the animal with which it has been inoculated. For instance, a solution of ox blood or serum in 0.8 per cent. sodium chloride is precipitated by the serum of a rabbit which has had ox-serum injected into it. Numerous similar instances are given, including the detection of human blood by human-rabbit-serum. It is suggested that horse-flesh in sausages may be detected in a similar way by the use of horse-rabbit-serum, but the reaction is stated to fail should the sausages have been previously boiled or smoked. w. P. 8.

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DOI:10.1039/AN9042900009

出版商:RSC    

年代:1904

数据来源: RSC

摘要:

THE ANALYST. INORGANIC ANALYSIS. The Iodometric Determination of Gold in Dilute Solutions. Ralph N. Max- son. (Zeits. Anorg. Chem., xxxvii., 80.)--The author has made a number of experi- ments, comparing the relative accuracy of Gooch and Morley’s method (Am. JO~~YPZ. Sci. SiZZ., viii., 1899, 261), which depends on the reaction 3KI + AuCl, = 3KC1+ AuI + I,, with that proposed by Rupp (Berichte, xxxv., Z O l l ) , in which an excess of arsenious oxide is allowed to act on the gold chloride solution according to the equation- 3As20, + 4AuC1, + 6H,O = 3As205 + 12HC1+ ~ A u , the excess of As,O, being then titrated with iodine. He finds that in the last method the gold is only precipitated if sufficient bicarbonate is present to neutralize all the acid, and shows that the first method is by far the more accurate, the error being only about one-tenth of that occurring with the second method when similar quantities of gold (from 9 to 0.05 milligrammes) are being determined.A. G. L. The Detection of Traces of Lead and Manganese. A. Trillat. (A?z?z. de Chim. anal., 1903, viii. , 408-410.)-The tetramethyl base of diphenylmethane, CH,[C,H,N(CH,),],, gives in acetic acid solution a bright blue colouration with certain metallic peroxides (lead, manganese and copper), due to the formation of the corresponding hydrol, CH.OH[C,H,N (CH3),I2. The reagent is prepared by heat- ing for an hour on the water-bath a mixture of 30 grammes of dimethylaniline, 10 grtlmmes of formaldehyde, and 200 C.C. of water rendered acid with 10 grammes of sulphuric acid. After cooling, the liquid is treated with a large excess of sodium hydroxide, and the excess of dimethylaniline expelled by means of a rapid current of steam. The crystals that form on now cooling the liquid are purified by a single recrystallization from alcohol, 15 to 20 grammes being eventually obtained.For the preparation of the reagent 5 grammes of the crystals are dissolved in 100 C.C. of water containing 10 grammes of pure acetic acid, and this solution is kept in a stoppered bottle in the dark. I n testing for lead the substance is converted into sulphate azd treated with a hot saturated solution of sodium hypochlorite (2 drops to 0.01 gramme of dry residue). The chlorine is expelled by ignition, the reagent added directly to the residue in the dish, and the colour produced compared with that given by water containing a known quantity of lead peroxide in suspension.The test is capable of detecting 1 part of lead peroxide in 3,000,000, and a clear reaction is obtained with rain-water that has been left for forty-eight hours in contact with granulated lead. To insure the absence of manganese in certain cases, all that is necessary is to wash the ash after formation of the sulphates. In applying the test to manganese, the ash of the substance should be treated with pure sodium hydroxide to form the peroxide, and the test continued in the same way as described above. I t is necessary to prove that copper is absent. By this means the author has obtained the blue coloration with 0.01 gramme of the ash of potato, beetroot, dahlia root, various leguminous plants,THE ANALYST.13 extract of oak, chestnut, etc. The ash of laccase and of an extract of RzLssula delica gave an intense reaction, and in the case of the latter, at least, the author infers that the manganese is present in the form of a peroxide compound. C. A. M. On the Addition of Litharge in the Assay of Lead. A. Copalle. (An?z. de Chim, anal., 1903, viii., 412-415.)-1n determining the amount of lead in poor ores by the dry method, it is usual to add to the fusion mixture a definite weight of litharge containing a known amount of lead, which is subsequently deducted from the amount found. As the amount of lead in the litharge is determined by fusion with alkalies alone, the conditions are not identical with those of the actual assay, and the author has therefore made experiments to determine the influence of different gangues, such as occur in lead ores, upon the litharge assay.In each case 25 grammes of litharge were fused under identical conditions in the presence of 25 grammes of different gangues, and the following amounts of lead found as the average of three or more closely concordant results : Litharge alone, 89.48 ; with quartz, 89.12 ; with pyrites, 87.60 ; with blende, 88-68 ; with natural barium sulphate, 88.32 ; with calcite, 89.12 ; and with clay, 88-96-per cent. Hence the author concludes that, in order to obtain the true amount of lead in the assay of a given lead ore, it is necessary in standardizing the litharge used, to add to it gangues of the same kind and quantity as are present in the lead ore, and that this is especially the case when the latter contains sulphur.C. A. M. On the Separation of Antimony and Tin by Means of Oxalic Acid. F. Henz. (Xeits. Anorg. Chem,, xxxvii., 1.)-According to the author, Rossing’s modification of Clarke’s oxalic acid method (Zeitschr. analyt. Chem., xli., 1) does not effect a perfect separation, a small quantity of tin sulphide being always precipitated with the antimony sulphide, even when the operation is repeated. He found it possible, however, to separate the two metals completely by first oxidizing the solution of their sulpho-salts with hydrogen peroxide. The method is carried out by placing the sulphide solution, which must not contain more than 0.3 gramme of the alloy, in a 500 C.C.beaker, adding 6 grammes (one-third of the sum of the weight of the tartaric and oxalic acids) pure potash and 3 grammes tartaric acid (ten times the weight of the alloy), and then twice as much 30 per cent. hydrogen peroxide as is necessary to completely decolorize the liquid. After heating to boiling for a few minutes, the liquid is allowed to cool somewhat, and a hot solution of 15 grammes of oxalic acid added. The liquid, the volume of which should now be 80 to 100 c.c., is then boiled vigorously for ten minutes, after which hydroqen sulphide is led into the solution, which is still kept. boiling. Fifteen minutes after the antimony has commenced to come down the liquid is diluted to 250 C.C. with boiling water ; after another fifteen minutes the heating is interrupted, and ten minutes later the current of hydrogen sulphide is also %topped.The precipitate is filtered on to a, tared Gooch crucible, and is washed twice with a 1 per cent. solution of oxalic acid, and then with very dilute acetic acid; both washing liquids should be at the boiling-point and saturated with hydrogen sulphide.14 THE ANALYST. The Gooch crucible is placed in t\l wide tube sealed to a narrow tube at one end and fitted with a perforated rubber stopper at the other. A current of dry carbon dioxide is led through the tube, which is at the same time heated, first to 100" to 130" C. until the precipitate is dry, and then to 300" C. until it has been completely converted into Sb,S,. The heating may be done with a naked flame; for exact work it is best, however, to heat the part of the tube containing the crucible in a small drying- oven designed for the purpose.A Rose's crucible-lid may be placed against the stopper inside the tube to protect it against radiated heat. Ground-glass stoppers may also be used, but it is difficult to make them absolutely tight at first. The author prefers this method of determining antimony to all others, although he blso obtained good results by converting the sulphide to tetroxide, and by depositing the antimony electrolytically from a sulphide solution containing sodium sulphite or, preferably, potassium cyanide. The results obtained by this last method were, however, always slightly high. The tin in the oxalic acid filtrate is determined most readily by evaporating to a small bulk, and electrolysing the solution at 60" to 80" C.with a current of 0.2 to 0.3 amphe and 2 to 3 volts, 5 C.C. sulphuric acid (1 : 1) being added after six hours, after which the electrolysis is continued for another eighteen hours. The deposition of the tin is complete under these conditions, and the deposit is easily handled. The author found that this method gives the best results for tin, electrolysis from a sulphide solution giving deposits of an unsatisfactory nature. If the tin has been originally obtained as sulphide during the course of an analysis, it may be dissolved in acid ammonium oxalate, a few C.C. of sulphuric acid being added after the electro- lysis has been in progress for some hours. As regards the method of separation, practically theoretical results are obtained for the antimony, but the values found for the tin are generally somewhat low (maximum error 0-0036 gramme on 0.2 gramme tin).A. G. L. Qualitative and Quantitative Estimation of Traces of Antimony in the Presence of Large Quantities of Arsenic. (Chem. News, Ixxxviii., 261.)-The author describes the following methods in order of increasing sensitive- ness : The platinum-tin couple method consists in immersing a piece of tin for half an hour in a 25 per cent. hydrochloric acid solution of the antimony contained in a small platinum crucible, or in a dent made in a platinum sheet. The piece of tin should be pointed, the pointed end dipping into the liquid, and should be bent over so as to again touch the platinurn at another point.Even with only 0.04 milli- gramme antimony per C.C. a black stain will be produced; and as $T C.C. of liquid suffices for the test, 0-002 milligramme antimony may be recognised in this way, whilst 0.001 milligramme will give a dark stain in one hour. If arsenic is present, it must be thoroughly oxidized by evaporation with nitric acid, the residue being taken up in hydrochloric acid ; its quantity must be less than 5 milligrammes per C.C. If zinc is substituted for tin, the test is rendered far less sensitive. By using silver instead of platinum the method is made more sensitive, OoOO1 milligramme antimony giving a dark stain, even in presence of 1 milligramme of arsenic. In this case the G. Denigha.T E E ANALYST. 15 duration of the test should not exceed five minutes.An ordinary silver coin may be used instead of pure silver, In the czesium salts method, a reagent is used consisting of 1 gramme cesium iodide and 3 grammes cesium chloride dissolved in 10 C.C. water, with the addition of a drop of 10 per cent. ammonia. I n examining stains obtained on platinum by means of tin, or deposited on porcelain from the flame of a Marsh apparatus, the stain should be treated with nitric acid, and the solution evaporated in a small porcelain crucible on the water-bath. On the dry residue a very small drop (0.001 c.c.) of the caesium reagent is placed and spread out by means of a fine glass rod; another small drop of 10 per cent. sulphuric acid is then added and mixed with the reagent. A red colour is developed after a short time, which should not disappear on adding a drop of sulphurous acid, and the intensity of which is a measure of the amount of antimony present. If, at least, 0.01 milligramme is present in the original dry residue, it may be dissolved in 0.1 C.C.of 25 per cent. hydrochloric acid; on placing a drop of the cesium reagent in the centre of this drop and waiting for two minutes, well-defined hexagonal crystals of the double iodide of czsium and antimony appear, which may be observed under the microscope. The quantity of arsenic present should not exceed 5 milligrammes per 01 c.c., as otherwise iodine may be liberated by the reduction of the arsenic acid. A. G. L. A Rapid Method for the Determination of Arsenic in Arsenopyrite. J. L. Danziger and W.H. Buokhout. (Sch. of 1CliYzes Quart., xxiv., 400.)-Half a gramme of the finely-ground ore is mixed with 10 to 15 grammes sodium peroxide in an iron crucible, the whole covered with a layer of peroxide, and heated very gently until the mass has sintered together. The heat is then raised to bright redness for five minutes with occasional agitation of the melt, which is then treated with 100 C.C. of boiling water, the whole being transferred to a 200 C.C. flask and made up to the mark; 100 C.C. are decanted through a dry filter-paper, made strongly acid with concen- trated hydrochloric acid, and boiled down to 75 C.C. Another 75 C.C. of hydrochloric acid (specific gravity 1.2) are then added, the solution is allowed to cool to room temperature, 3 grammes of potassium iodide in saturated aqueous solution are added, and the liberated iodine is titrated with standard sodium thiosulphate solution, drops of starch solution on a white tile being used as indicator.The thiosulphate is best standardized against arsenic acid; the value thus found is about 1 per cent. higher than that calculated from its iodine or copper value. The starch indicator should not be added to the liquid itself, as it would be hydrolysed by the large amount of acid present. Should antimony be present in the ore, it is removed from the acidified extract of the melt by Bunsen’s method, the filtrate containing the arsenic being then oxidized with potassium chlorate and hydrochloric before applying the above method. The authors state that even when considerable quantities of arsenic are present in the solution the precipitate of antimony pentasulphide obtained is free from arsenic.The method gives good concordant results, slightly higher than those obtained with other processes. A. G. L.16 THE BNALYST. A Study of the Quantitative Determination of Antimony.-Part 11.: An Investigation of the Herroun-Weller Volumetric Method for the Determination of Antimony. Lewis A. Youte. (Sch. of Mines Quart., xxiv., 407.)-From the author's work it appears that antimony is quantitatively oxidized to the antimonk state by nitric acid or potassium chlorate in hydrochloric acid solution; that the solution obtained may be boiled to expel chlorine without volatilizing any antimony ; and that complete reduction to the antimonious state is effected by boiling with sulphur dioxide in an open or closed vessel, by sulphur dioxide and potassium bromide, and by potassium iodide in cold hydrochloric acid solution.Using the Herroun-Weller method for the determination of antimony, in which the oxidized solution is reduced with potassium iodide and hydrochloric acid in the cold, the liberated iodine then being titrated with sodium thiosulphate solution, the author obtained results which are concordant, but show a consistent loss of 1 per cent. of the antimony. The cause of this loss is as yet unexplained. A. G. L. The Determination of Manganese in the Presence of Iron. G. v. Knorre. (Zeit. f. angew. Chem., 1903, xxxviii., 905.)-The author has already proposed a method for the estimation of manganese by oxidizing with persulphuric acid, filtering off the precipitated manganese dioxide and titrating (see ANALYST, 1902, 68).He now finds that this may be simplified by omission of the filtration, a fact which is of special importance in the case of irons and steels containing less than 0.5 per cent. of manganese, because theae give precipitates which are liable to pass through the filter. I t is, however, essential that before the titration the persulphuric acid be entirely destroyed by prolonged boiling, otherwise the results would be too high, especially if there be nickel or copper in ths sample that is being examined. Hydrochloric acid must not be present in the solution, but nitric acid has no ill effect. If there be a large proportion of phosphoric acid present, the results will be too low, but the amounts that occur in the analysis of ordinary iron and iron ores have no appreciable effect.Great excess of acid must be avoided, as it prevents the complete precipitation of the manganese. The sample is dissolved in sulphuric acid or nitric and sulphuric acid, methyl orange is added, and the mid is neutralized with ammonia or potash. Then ammonium persulphate is added in excess, 3 or 4 grammes to each gramme of iron, the solution is diluted to about 300 c.c., and 20 C.C. of dilute sulphuric acid (specific gravity 1.17) are added. The liquid is now boiled for fifteen to twenty minutes, with occasional shaking to prevent bumping; it is cooled and a slight excess of a standard solution of hydrogen peroxide is added.When the manganese dioxide is completely redis- solved, the excess of hydrogen peroxide is estimated by titration with permanganate. A. M. Electrolytic Separation of Iron and Xanganese. J. Koster. (Ber. , 1903, xxxvi., 2716-2719.)-1ron can be readily separated from considerable quantities of manganese by the following modification of Classen's process : The solution con- taining the metals in the form of double oxalates with ammonium (prepared by theTEE ANALYST. 17 addition of about 10 grammes of ammonium oxalate) is electrolysed without the application of heat, and as soon as a deposit of manganese peroxide appears on the anode, a few C.C. of a 10 per cent. solution of phosphorous acid are added to reduce it. This addition is repeated &B required, but should not be made more frequently than is necessary, since otherwise the reduction of the iron is retarded ; and in any case no more phosphorous acid should ba introduced after the manganese has been kept in solution for two hours, since the bulk of the iron will then have been deposited.As a rule 5 C.C. of the 10 per cent. solution sufficiently retard the deposi- tion of manganese. After complete separation of the iron the platinum basin is washed with water without interrupting the current, and finally with pure alcohol, any slight particles of manganese deposit being removed by means of a soft brush. Results agreeing excellently with the theoretical amounts were thus obtained under the following conditions : Voltage, 3 to 4 ; amperage, NDIo,= 1.5 to 2 ; ordinary temperature; time, 5 to 8 hours, according to the amount of phosphorous acid used.C. A. M. The Electrolytic Separation of Manganese and Iron, of Aluminium and Iron or Zinc, and of Zinc and Iron. Hollard and Bertiaux. (Annd. Chim AnaZyt., viii., 324.)-Manganese and iron may be separated by electrolysing the solution of their sulphates, to which a little ammonium sulphate and 20 to 25 C.C. of a saturated solution of sulphur dioxide in water has been added before making it slightly ammoniacal. The determination is carried out at 40" C., using a current of 1 ampere. The cathode should have a large surface, whilst the anode surface should be as small as possible. Under these conditions the iron deposited is free from manganese, whilst the sulphur dioxide present prevents the formation of manganese dioxide, which would carry iron oxides down with it, The iron on the cathode, how- ever, contains a little platinum dissolved off the anode, and for this reason cannot be weighed directly.It is dissolved in dilute sulphuric acid, the solution filtered from platinum and titrated in an atmosphere of carbon dioxide with potassium per- manganate. To determine the manganese in solution the current is again passed through, but in the reverse direction, so as to have a large anode surface. The solution is kept at 90" to 95" C. At the end of several hours the current is inter- rupted by withdrawing the cathode, the anode being left in it for another thirty minutes to reduce any higher oxide of manganese to the state of dioxide.The peroxide is then washed with hot water into a beaker, filtered on to asbestos, and washed with hot water. Filter and precipitate are then treated in a beaker with hydrochloric acid and potassium iodide, and the liberated iodine is titrated with thiosulphate. The results obtained in this way are fairly good, the largest error being 5 milligrammes on 0.2 gramme iron. Iron may be separated from aluminium in the same way as from manganese, except that ammonium citrate is also added to the solution, good results being obtained. The method may also be used to separate nickel and aluminium, the nickel originally deposited being dissolved in sulphuric acid, the liquid filtered, and electrolysed after being made alkaline with ammonia, but the results obtained are not very satisfactory.18 THE ANALYST.To separate iron from zinc, sulphurous acid is added to the solution of the sulphates, which is then exactly neutralized with sodium hydrate ; potassium cyanide solution is then added, and the solution electrolysed in the cold, using 8 current of 0.3 ampere and a cathode covered with copper. The zinc deposited always contains a little iron, which can be determined with potassium permanganate as above. A. G. L. The Electrolytic Precipitation of Nickel from Phosphate Solutions. Walter T. Taggart. (Journ. Anter. Chem. SOC., xxv., 1039.)-The author shows that nickel can be deposited completely and free from phosphorus from phosphate soh- tions, obtained by precipitating nickel sulphate solutions with a solution of dieodium hydrogen phosphate of specific gravity 1.038, dissolving the precipitate in phosphoric acid of specific gravity 1.347, and diluting with water.The conditions of the electrolysis were : N.D7,,, 3 amperes ; tension, 6 volts ; dilution, 175 C.C. ; tempera- ture, 50" to 70' C. ; time, nine hours; sodium phosphate, 135 C.C. ; phosphoric acid, 6.75 C.C. ; nickel, 0.3249 gramme. By raising the temperature to 88" C., the time may be shortened to five hours, working with a current density of 2.25 amphres. A. G. I;. On a Method for the Separation of Cobalt from Nickel,.and the Volumetric Determination of Cobalt. a. L. Taylor. (Chem. News, lxxxviii., 184.)-The author again calls attention to his modification of Rose's method for the separation of nickel and cobalt (ANALYST, xxvii., 285), which has been found to work well in the assay of cobalt 01188.Either calcium or barium carbonate may be used, provided only that the solution is neutral. Zinc ehould be absent, as it prevents the pre- cipitation of the cobalt peroxide, the composition of which approximates to the formulae Co901* and Co,Oll, and is sufficiently constant to enable the chlorine evolved on treating it with hydrochloric acid to be used as a measure of its quantity. A. G. L. The Analysis of Ferrosilicon. H. Lidhplm. (Zed. f. angew. Chem., 1903, xliv., 1060.)-The author overcomes the great difficulty in dissolving these alloys by fusing them with sodium peroxide. The reaction is so violent that it is better to add some cmbonate to moderate it. The ferrosilicon (0.2 to 0.3 gramme) is mixed with five times the quantity of sodium and potassium carbonate in a nickel crucible, which is then gently heated to drive off moisture.To the dry,mass twice as much sodium peroxide is added, and the mixture is gradually fused, the ignition being continued until no solid lumps can be seen. When cool the crucible is placed in a covered beaker of warm water to dissolve out the mass. The solution is widified with hydrochloric acid, and iron and silicon are determined in the usual way. A. M. The Determination of Uranium and Uranyl Phosphate by means of the Zinc Reductor. 0. €3. Pulman, Jun. (Zeds. Anorg. Chem., xxxvii., 113.)-The author has made a number of determinations, using Kern's method of reduction (Journ.THE ANALYST. 19 Amer. Chem. Soc., xxiii., 716), and finds that, contrary to Kern’s statement, the reduction, if carried out in an atmosphere of carbon dioxide, gives oxides lower than the dioxide.In contact with air, however, the solution is immediately oxidized to the dioxide stage. He therefore prefers to work in an atmosphere of air. The reductor used is constructed from a 50 C.C. burette filled to R height of 1 inch with broken glass; above this is placed a pad of glass wool, and then an 18-inch layer of 20-mesh amalgamated zinc. The uranium must be in the form of sulphate; the solution, which should measure about 100 to 150 c.c., should contain one-sixth of itsvolume of concentrated sulphuric acid. I t is heated to 100’ C. before being poured through the reductor, which has previously been warmed by pouring hot dilute sulphuric acid (1 : 6) through it.The reductor is washed first with dilute sulphuric acid and then with 200 C.C. hot water, and the reduced liquid at once titrated with & potassium permanganate solution. For 0.2 gramme UO,, the passage of the liquid through the reductor should take about eight to ten minutes, and for 0-3 gramme UO, about thirty minutes. As this modified method gave very good results, it was applied to the determina- tion of uranium in uranyl phosphate precipitated from a boiling solution containing ammonium acetate and acetic acid. This precipitate is so finely divided that it passes through a double filter-paper or through a layer of ordinary asbestos ; it may be retained by using only the fine asbestos fibres which remain in suspension when the asbestos is shaken up with water and allowed to stand for one minute, but the filtration and washing are tedious, and the results obtained by passing the sulphuric acid solution of the precipitate through the reductor are only moderately satisfactory.Suction must be applied to the receiving flask to effect this. A. G. L. The Estimation of Titanium. J. Watson Bain. (Joum. Amer. Chem. Soc., xxv., 1073.)-The author has examined various methods for the determination of titanium, and concludes that Gooch’s method is the best. Baskerville’s method (Joum. Soc. Chem. Ind., xix., 419), in which sulphur dioxide is passed into the neutralized solution and the titanium then precipitated by a few minutes’ boiling, is superior to the methods of Arnold, founded on the insolubility of the phosphotitanate of iron in dilute hydrochloric &id, and of Hilger and Haas, in which the mixed oxides of titanium and other metals are reduced in a current of hydrogen and then treated with dilute acid.Excellent results are obtained by Walker’s method, in which hydrogen peroxide is added to the titanium sulphate solution, which is then slowly poured into ammoniacal hydrogen peroxide; but as this operation must be repeated three times, the method requires too much time for ordinary work. A. G. L. The Determination of Small Amounts of Potassium in Aqueous Solutions. F. K. Cameron and G. H. Failyer. (Journ. Anzer. Chem. SOC., xxv., 1063.)--The method described depends on the pink colour produced by adding potassium iodide to a solution of platinum salt, and gives especially good results with solutions con- taining one to ten parts of potassium per million, although its usefulness is not20 THE ANALYST.confined to these limits. Solutions in which potassium is to be determined must be free from ammonia and organic matter ; their removal is effected, if necessary, by evaporation with sulphuric acid and ignition of the residue. This residue is then treated with a little hydrochloric acid and an excess of platinic chloride, and the whole evaporated to a stiff paste. The excess of platinum is then removed by six or eight washings with 95 per cent. alcohol, the precipitate being filtered on to asbestos, using gentle suction to remove the alcohol. I t is then dissolved in a small quantity of hot water, a drop of concentrated hydrochloric acid added after cooling, and then an excess of potassium iodide solution.The red colour developed is compared with a standard after, at least, four hoilrs' standing. The colour should be allowed to develop in as strong a solution as possible, but if the liquid is diluted afterwards, the diluted liquid should be allowed to stand a t least one hour before a reading is taken. The standard solution used for comparison contains 2 parts of potassium per million. It is contained in a cylinder fitted with side-arm near the bottom, by means of which the height of the liquid in the cylinder may easily be varied. The authors have also found that, by adding a little alcohol to the liquid in which the pink colour has been developed, and heating, a strong, clear, yellow colour is produced.By matching this yellow colour against that of a standard solution, a check on the reading obtained with the pink colour is given. Both readings agree well with each other and with the theoretical values. The method is applicable even when as much as 50 parts sodium, 50 parts magnesium, and 50 parts calcium are present together with 50 parts potassium per million, the values found ranging from 48.0 to 53.5 parts per million. A. G. L. On the Occurrence of Iron in Sulphur. R. v. Hasslinger. (Momtshefte f. Chew,., xxiv., 729.)-The author shows that all commercial foyms of sulphur, from the native to the very purest product, leave, on distillation, a black residue consisting only of iron and carbon, probably in the proportions indicated by the formula FeC,.This black residue may also be obtained by simply boiling the sulphur for some time. I t appears to be a decomposition product of a volatile compound of iron, carbon, and sulphur, and is always formed when a bituminous material (e.g., asphalt) is distilled with an iron compound and sulphur. It is only-very slowly decomposed at the temperature of boiling sulphur. The author was only able to obtain a sulphur which did not give this product by cautiously oxidizing pure hydrogen sulphide. A. G. L. On a New Method for the Preparation of Pure Iodine. Launcelot W. Andrews. (Amer. Chenz. Journ., xxx., 428.)-Potassium iodide is powdered together with one and four-tenths times its weight of potassium bichromate, both salts having previously been separately fused to insure dryness.The mixture is introduced into a, wide tube closed at one end, and is heated for some time to 200° C. in a current of dry air to expel the last traces of moisture. The interior of the tube is then carefully dried with cotton, a plug of glass wool is placed above the mixture, and a second short tube is slipped over the open end of the first one, so as to fit it as closely as possible.THE ANALYST. 21 The mixture is then gradually heated to fusion, the tube being kept in an inclined position. 5K,Cr,O, + 6KI = 8K,CrO, + Cr,O, + 61. Iodine is liberated according to the equation- At the end of the operation the upper end of the tube carrying the sublimate is cut off, Even if the iodine used contains bromide or chloride, the iodine obtained is pure, since these Salt8 are not decomposed when fused with potassium bichromate.A. G. L. The Use of Potassium Tetroxalate in Volumetric Andysisis. 0. Kiihling. (Zeit. f. mzgezu. Chem., 1903, xxxvii,, 1031.)-Objections have been raised by Duprh and others to the employment of this substauce on the ground that it is not of constant composition, but is liable to contain varying proportions of water of crystallization. The bad results obtained by some workers are ascribed by the author to their having dried the compound over sulphuric acid, whereas it should have been used in the air-dry condition. The following method yields a product possessing a satisfactory degree of purity : Commercial oxalic acid is crystallized twice from hot hydrochloric acid having a specific gravity of about 1.07, and then three times from boiling distilled water.The product thus obtained, which must give no precipitate with silver nitrate and leave no residue on ignition, is used to make a cold saturated solution by allowing it to stand for a day with a quantity of water insufficient entirely to dissolve it. Of this solution one-fourth is taken and titrated with a concentrated solution of pure caustic potash, using phenolphthalein as indicator; the other three-quarters are then mixed with it again and stirred well, whereupon a crystalline precipitate forms. This should be redissolved by heating the liquid, and be allowed to crystallize out again on cooling. The crystals are filtered off on hardened filter-paper and again recrystallized from a small quantity of hot water, filtered off, pressed between hardened filter-paper, and allowed to dry in the air until they no longer adhere to the sides of a glass vessel. This usually requires about two days. The composition of the resultant product is constant, and agrees very closely with that calculated from the formula C204HK,C20,H,,2H,0. I n a series of determinations, in which the tetroxalate was compared by means of permanganate solution with a thiosulphate solution standardized against specially purified iodine, the agreement was very satisfactory. A. M. Hydrogen Peroxide in Crystals. R. Willstatter. (Berichte, xxxvi., 1828 ; through Pharnz. Jown., 1903, lxxi., 777.)-Various salts are described in which hydrogen peroxide appears to replace the water of crystallization. For instance, beautiful prisms, having the formula (NHJ2S04.H,0,, separate out if ammonium sulphste be dissolved in a 30 per cent. solution of hydrogen peroxide and placed over sulphuric acid in a desiccator. The crystals smell like ozone, effloresce in air, but keep well in closed vessels. Sodium sulphate forms a similar compound, Na,S0,H,0.~H,02, as do also alum, aluminium sulphate, borax, and sodium acetate.22 THE ANALYST, These crystals give up their hydrogen peroxide to ether and other solvents, and may therefore be of use in carrying out reactions with peroxides in indifferent solvents. They may, perhaps, replace the persulphates and percarbonstes for technical purposes. w. P. s.

ISSN:0003-2654    

DOI:10.1039/AN9042900012

出版商:RSC    

年代:1904

数据来源: RSC

摘要:

22 THE ANALYST, APPARATUS. A Self-Igniting Bunsen. H. Schimmel. (Chern. Zeit., 1903, xxvii., 1037.)- This is a Bunsen fitted at its base with a two-way cock, from which a by-pass tube rises to a short distance below the orifice of the burner, where it carries a small ball of platinum black. When the crank handle of the cock is at one end of its limited travel, the gas is entirely shut off; when the handle is moved to its intermediate position, gas is admitted to the by-pass, and is inflamed by the platinum ; and when the crank is thrown right over, the by-pass is cut out and the main supply turned on, A sloping hood, supported by the large tube, protects the platinum black and the by- pass tube from any liquids which may be spilt. The apparatus is patented in Germany, the maker being J.Schober, of Berlin. F. H. L. A Reading Device for Burettes, etc. H. Gockel. (Chem. Zed., 1903, xxvii., 1036.)-The annexed diagrams represent a simple reading device for burettes, which not only renders it easier to view the critical edge of the liquid meniscus accurately, but also avoids all errors caused by parallax. It consists of a pinch-clamp, the jaws of which are so cut that it will fit vessels of different diameter, yet, provided the vessel is vertical, will always attach itself in a truly horizontal plane. Thus, if the eye is so placed that the axis of vision is parallel to the top or bottom of the apparatus, the burette must be read normally. The clip is applied to the burette with its upper I ? 11 Ha' Men ii CIU § surface 2 or 3 millimetres below the lowest part of a concave meniscus, or with its lower surface 2 or 3 millimetres above the highest curve of a convex meniscus ; and in this position it cuts off superfluous light, so that the height of the liquid may be ascertained more exactly.If the volume of 0.1 C.C. occupies a space of 1 millimetre in the tube, it is claimed for this instrument that a reading may be made to 0.01, or even 0.005 C.C. The apparatus can be obtained from Sauer and Gockel, of Berlin. F. H. L.THE ANALYST. 23 Some New Apparatus. A. Waeg- ner. (Oesterr. Chem. Zeit., 1903, vi., 409.)-A CO, Apparatus.-This consists of a pear-shaped flask K fitted with a, rubber cork having two holes. Through one passes a tube D to the bottom of the vessel, where it is narrowed and curved upwards slightly ; this serves for the final admission of air, and is closed during the decomposition by a clamped rubber tube.Through the other hole passes a three-way tube C, cut off obliquely just within the flask, through which is placed a glass rod G with a hook at its lower end to carry the vessel H holding the carbonate. This rod travels air-tight through a rubber sleeve at the top of the T-piece, and is pushed downwards gradually as decomposition proceeds. The lateral aperture of the three-way tube bends upwards and becomes a long vertical tube A 12 millimetres in diameter, which is packed with glass balls. To its top is joined an inverted U, which connects it to a similar descending tube B, three - quarters filled with - I calcium chloride, and charged with E copper sulphate pumice beneath.The exit of the latter tube leads to the absorption vessel for the carbon dioxide, which may be either a potash apparatus holding the carbonate has a small lateral hole near its base for the entry of the decomposing acid; this hole is covered with glass-wool. Apparatus f o r Filtrations with the Gooch CrucibEe.-This consists of a pear- shaped separating funnel ,with a twice- bored rubber cork. One hole carries a tube funnel in which the crucible is placed and made tight with the usual rubber washer. The other bears a, bent FiS f or a tube of soda-lime. The tube H L three-way tube, one limb terminating in a stopcock, the other passing to the24 THE ANALYST. pump. By this arrangement, when some liquid has been collected and found to contain asbestos fibre or to be otherwise turbid, the vacuum in the funnel is broken by opening the stopcock mentioned, and the filtrate is run out of the separating funnel through the stopcock at its base.Condensation in Organic Combustion- Tubes.-To prevent this trouble, a sleeve of silver foil is put round the projecting part of the tube so as to extend about 1 centi- metre into the furnace and to about 2 millimetres short of the cork. The high heat- conducting power of the metal keeps the temperature in the tube at a sufficient point to avoid condensation without injuring the rubber stopper. F. H. L. - -. . - ___ _____ ._ Gas Furnace for the Laboratory. IC. Friedrich. (Zeits. f. angew. Chem., 1903, xxxvi., 857.)-The furnace is so constructed that several kilogrammes of material can be treated at one time, and the flame can be so regulated as to produce the same effects as are obtained on the large scale.The body of the furnace rests on an iron plate b, supported by four columns a, and is held together by the iron casing A , in which there are a number of openings. I The The GKOUND PLAS. 700 0 7UU 200 300 900 M~~ 1 t - , hearth B is supported upon a separate plate p , which is held up by the bars ma. level of the hearth can be adjusted by means of the wedges n. The air and gas are introduced through the two openings cl, c2, which are inclined towards each other. The gases inside the furnace are caused to rnix'thoroughly by striking the opposite wall. They then pass out through the opening d and up the vertical flue E, which is lined with fire-clay.The fused material can be run off through the channel K, or can*be drawn along the gutters rl r2 into the holes ql q2, below which receptacles can be placed to receive it. The two There are two working doors, fl and f2.THE ANALYST. 25 burners D each have aeven jets, the upper five of which are controlled by common taps, whereas for the lower two there is a separate tap for the gas and another for the air. By adjusting these taps it is possible not only to regulate the temperature, but also to produce either an oxidizing or reducing atmosphere immediately over the work. The conditions in the furnace can further be varied-by placing wedges of clay in the openings cl, c2 and d, by raiaing or lowering the hearth B, and by pushing in or out the fire-clay damper 2.The hearth can be removed and replaced by one of EI different shape or of another material. The roof C can also be taken off, SO as to allow repairs to be executed. Using coal-gas and air at a pressure of 200 millimetres of mercury, the temperature rose in ten minutes to 1,195" C., and in a hundred minutes to 1,420' C. A higher temperature could be obtained by replacing part or all of the air by oxygen. Some improvements (ibid., 1077) have been made in the furnace previously described. An arrangement has been introduced for raising and lowering the hearth by means of a screw and hand-wheel. The lid of the furnace also has been lightened, and an aperture has been made in it for the introduction of a pyrometer." Issem " burners have been substituted for those used originally, but they are arranged as before, two on each side one above the other. These render it possible to attain a higher temperature: in ninety minutes this rose to 1600' C., although a more powerful fan than the one used might have been advantageous. The apparatus is manufactured by Karl Issem, Berlin-Reinickendorf. A. M. Carbon Dioxide Apparatus for Use in Damp Air. A. C. Kuyt. (Chem. Zeit., 1903, xxvii., 1086.)-The author states that errors of from 3 to 9 per cent. in the estimation of carbon dioxide with the aid of the Geissler apparatus are not uncommon in the tropics, where the atmosphere is so highly saturated with moisture. He has therefore added to the usual form of apparatus extra drying-tubes, as shown by the annexed illustration. A and C are charged with calcium chloride ; when the apparatus is being weighed, their places are taken by the stoppers, D and B. The tube, B, contains soda-lime. The air which enters when the strong hydrochloric acid in G is allowed to run down into the flask is freed from moisture by C, while any acid vapours that may arise are caught by B. The tube, B, similarly protects the sulphuric acid in D from the moisture of the atmosphere. The apparatus is made by Geissler (Miiller), of Bonn. F. H. L.

ISSN:0003-2654    

DOI:10.1039/AN9042900022

出版商:RSC    

年代:1904

数据来源: RSC

摘要:

26 THE ANALYST. REVIEWS. BACTERIA IN MILK AND ITS PRODUCTS. By H. W. CONN, Ph.D. (London : Rebman, This work contains chapters on the nature and properties of bacteria, the source of bacteria in milk, the types o€ milk bacteria. and the growth of bacteria in milk; then follow important chapters on milk bacteria and health and the protection af the consumer. The bacteria in butter and cheese are discussed, snd the final 40 pages are devoted to the bacteriological analysis of milk. The information in the earlier chapters is concise and up to date, though by no means exhaustive, and the illustrations might with advantage have been in many instances replaced by micro-photographs. The last chapter is somewhat novel. The author has endeavoured to give methods for the examination of milk which will give more useful information than a mere enumeration of the numbers of organisms, and will not occupy the great length of time that even a moderately complete qualitative analysis entails.There is no doubt that, in the author’s words, “such a method of bacteriological study is an advance.” Still further information might be gained, with hardly any more trouble, if a phenol-agar plate culture were added to the litmus, gelatine, and agar cultures, and the fermentative test recommended. The quantity of water used in making the culture medium specified on p. 253 should evidently be 500 c.c., not 500 litres. A fairly complete list of references to recent literature and an efficient index complete the work. Ltd. Price 6s- Pp. 290 [pp. 1-16 omitted]). H.D. R. FOODS: THEIR COMPOSITION AND ANALYSIS. By ALEXANDER WYNTER BLYTH and MEREDITH WYNTER BLYTH. Fifth Edition. (London : Charles Griffin and G o . Price 21s.) This work is, we believe, the largest and most ambitious book on the analysis of foods which has been published in this country for the use of Public Analysts. I t contains a vast mass of well-arranged information most industriously collected from numberless sources, much of which is not to be found in any other book on the subject ; the historical part relating to adulteration being particularly interesting reading. The history is brought down to the present date, and includes, on p. 33, a, discussion on the ( ( Sale of Food and Drugs Act, 1899,” (wrongly cited by the authors as ‘‘ The Food and Drugs Amendment Act, 1889 ”).The work abounds in good illustrations, ranging from physical apparatus, absorption spectra, drawings of microscopical structures and bacterial cultures, to anatomical structures. It must further be freely acknowledged that the book has, in very many respects, been brought up to date, and certainly contains much sound and useful information. Modern chemical thought has, on the whole, left this fifth edition untouched. Of this fact the chapter on ‘‘ Carbohydrates ” affords a striking illustration. Accord- ing to the authors, ‘( carbohydrates ” are classified into three groups : The get-up in general leaves nothing to be desired.THE ANALYST. 27 1. THE GRAPE-SUGAR GROUP, to which ‘‘ belong sugars containing 3, 4, 5, 6, 7, 8, and 9 carbon atoms.” Very few chemists would be willing to accept this definition, the grape-sugar group being generally limited to the hexoses.2. THE CANE-SUGAR GROUP.-“ To this group belong sugars of the formula C,, and of the formula Cis'" No carbohydrate with C,, has any right whatever to be included in this group, and cane-sugar is not a type of any group; there is no other disaccharide existing which has a similar constitution. 3. THE CARBOHYDRATES. -‘‘ To this group belong the so-called polysaccharides, cellulose, starch, glycogen, gammy matters, and dextrin. ’’ There can be no justifica- tion for this limited application of the term (( carbohydrates.” The grape-sugars, the ‘‘ cane-sugar group,” raffinose, and an endless string of other substances, have the same claim as the polysaccharides to be called carbohydrates.The scientific information given concerning these three classes is exceedingly scanty, and we should have expected to have found reference made to the views of Fischer, Tollens, and other modern writers. On p. 104 it is correctly stated that cane-sugar crystallizes from its aqueous solution in anhydrous crystals ; but on p. 121 an analysis of white sugar-candy is given, which states, quite incorrectly, that candy contains 20 per cent. of water. No reference is made to the use of tin chloride in colouring Demerara sugar. Amongst substances enumerated as adulterants of sugar are the following : ‘( glucose, or starch sugar, sugar of milk, dextrin, chalk, plaster, sand, and various species of flour,” nearly all of which are now no longer met with.Similarly, among the table of colours alleged to be used in the colouring of confectionery, such substances as chromate of barium, lead compounds, arsenic, antimony, Prussian blue, sulphate of barium, and salts of zinc, are enumerated, the use of which is now obsolete. On p. 111 it is stated that lzvulose is uncrystallizable, and that it has not been found possible to separate it entirely from crystalline glucose; also that when pure it presents simply the characters of a colourless syrup. It cannot surely be unknown to the authors that for a good many years past laevulose has been prepared in a state of almost perfect purity as a well-crystallized body, and largely sold for therapeutic purposes. The authors suggest that some sweetmeats are ‘‘ supposed to contain alcohol.’’ As a matter of fact, duty is actually levied on certain kinds of sweets, because they actually do contain alcohol.While, under wheat-flour, attention is drawn to the adulteration of flout with potato and leguminous starches which, as far as we are aware, have never been used in this country as adulterants, or if ever they have been employed have long ceased to be used, there is no reference to the adulteration of flour with ground maize, which even quite lately was largely practised in America. Maize was found in numberless samples examined in London until the United States Government took steps to repress this mode of adulteration. And, again, sulphate of copper, sulphate of zinc, chalk, and carbonate of magnesia, are given as adulterants of bread, though the interest which attaches to them is purely of a historical nature.Similarly, an unnecessary targe amount of space is devoted to processes for the28 THE ANALYST. detection of picrotoxin and picric acid in beer; nor does it seem worth while to enumerate as adulterants of pepper-linseed meal, pepper-leaves, mustard, whe& flour, sago, woody fibre, chillies, rape-seed, potato, spices, capsicum, manignette (otherwise known as guinea pepper), chicory, rye, powdered leaves of the laurel which had been previously used to wrap round extract of liquorice, bone-dust, marine salt, and various mineral adulterations. The statistics published for more than twenty- five years past by the ‘Local Government Board surely contain hard facts which are of more value in showing what are the adulterants of articles of food used at the present time.On the other hand, the table given on p. 169, showing the composition of infants’ farinaceous foods, is lamentably incomplete, and hardly gives more than a small fraction of the information which the analyst would require. This country was the first.to give attention in a scientific spirit to the detection of adulteration of food materials. I t set the example to the whole civilized world as regards legislation on the subject, and the English Adulteration Acts were the models upon which legislation in other countries was based in modern times. We were the first to have an Association of Public Analysts-the Society of Public Analysts-- largely devoted to the advancement of scientific knowledge for the repression of adulteration.We had the earliest books on the subject, and were years ahead of the Germans, French, and Americans on this subject. It would hardly appear to them from a perusal of the present work that our position is being maintained. The authors have an excellent opportunity of filling, in a manner worthy of our profession, the want of a comprehensive, accurate, modern, and fair work on the subject. Their book has passed through five, and will probably pass through more, edibions. We trust that whenever the opportnnity arises the authors will unsparingly throw overboard the antiquated and inaccurate information which is so apt to collect in books that pass from one edition to another, and that the work may be thoroughly brought up to date, and thus become an acknowledged standard work and a safe guide. FINAL REPORT OF THE ROYAL COMMISSION APPOINTED TO INQUIRE INTO ARSENICAL POISONING THROUGH THE CONSUMPTION OF BEER AND OTHER ARTICLES OF FOOD OR DRINK. THE final Report of the above Royal Commission was issued last month. As the matters dealt with in this Report are of such great interest and importance to analysts generally, it is proposed t o publish a somewhat full abstract in the February number sf the ANALYST.

ISSN:0003-2654    

DOI:10.1039/AN9042900026

出版商:RSC    

年代:1904

数据来源: RSC