摘要:

MARCH, 1905. Vol. XXX., No. 348. NOTE ON COMMERCIAL AMYL ALCOHOL. BY H. DROOP RICHRXOND, F.I.C., ARD J. A. GOODSON. (Read at the Meetiiag, December 7, 1904.) A CONSIGNMENT of amyl alcohol was found to give, when used in the Gerber method of fat estimation, constantly high results. With milks the average reading was 0.10 per cent. higher than gravimetric estimations, and with separated milks (con- taining about 0.1 per cent. of fat) 0.06 per cent. higher. This amyl alcohol complied with the specification laid down by one of us in conjunction with F. R. O'Shaugh- nessy, and when 1 C.C. was treated with 11 C.C. of water and 10 C.C. of sulphuric acid, only the faintest indication of an insoluble layer was seen on the surface. Various mixtures of amyl alcohol acid and water were made, and the layer read off in a Gerber bottle as if it were fat.1 C.C. amyl alcohol, 11 C.C. of water, and 10 C.C. of acid yielded trace. 2 7 , P , 10 $ 7 7 7 10 Y f ,, 0.12 3 9 9 2 ) 9.5 7 , 7 , 9.5 , Y ,) 0.04 4 , Y ? Y 9 I f 9 , 9 9 ) ,, trace. 5 , Y 9 8 8.5 f ? 7 , 8.5 ,, 9 , none.78 THE ANALYST. The impurity in this alcohol was soluble in the acid mixture, and the solubility 250 C.C. were distilled through a fractionating column : 124.5" to 127.5" 7 , 32 9 ) 127.5" to 128.5" 7, 36 9 ) 128.5" to 129.5" 7 2 62.5 ,, 129.5" to 130.5" 9 , 73 1 , 130.5' to 131.5" 9 7 18.5 ,, Leaving a residue of increased with the amount of amyl alcohol. 94" to 124.5" (corrected). 16 c.c distilled. 10 C.C. When 2 C.C. of each fraction were treated with 10 C.C. of water and 10 C.C.of sulphuric acid, no layer was observed to rise; but 2 C.C. of the residue gave a layer measuring 3.0, which had a smell of petroleum. The residue from the distillation of 500 C.C. was shaken with sulphuric acid, the layer separated, washed with water, caustic soda solution, and again with water, and dried with calcium chloride. This had a density of 0.803, and boiled at 190" to 230°, smelt of petroleum, and was slightly fluorescent. Mr. J. B. P. Harrison informs us that petroleum barrels are used as packages for &my1 alcohol, and that as much as 4 per cent. of petroleum has been observed. A milk which read 4-32 per cent. fat with the crude alcohol gave an average of 4-21 per cent. with various fractions of the distilled product, and a separated milk 0-17 per cent.with the crude and 0.12 per cent. with the distilled. Mixtures of amyl alcohol with varying amounts of petroleum were made : Iteadin~ with Percentage of Petroleum. 4-8 2.4 1-2 0.6 0.3 none Milk. 0.67 4.48 0.25 4.37 0-11 4.23 trace 4-19 doubtful trace 4.12 none 4.10 2 C.C. Alcohol, 10 C.C. Water, 10 C.C. Sulphuric Acid. Separated Milk. 0.48 0.25 0.16 0.12 0.09 0.09 We also found that the drying of the fat obtained by the method described by one of us with C. H. Rosier (ANALYST, 1899, xxiv., 172) took some hours before a constant weight could be obtained when this amyl alcohol was used. We conclude that : 1. The amyl alcohol in question contained about 1 per cent. of petroleum. 2. This quantity of petroleum is soluble in a mixture of the amount of amyl alcohol, sulphuric acid and water used in .the Gerber method, and is partially extracted by small amounts of fat (0.1 per cent.), and wholly by larger amounts.3. Amy1 alcohol which gives any visible insoluble layer when 2 C.C. are treated with 10 C.C. of water and 10 C.C. of sulphuric acid should not be used in the Gerber method; a blank Gerber test is insufficient. Van Haltrst (ANALYST, 1903, 213) and Siegfeld (ANALYST, 1904, 113) have stated that apparently pure amyl alcohol may give high results with Gerber's method, and it is probable that they were dealing with amyl alcohol containing small amounts of petroleum.THE ANALYST. 79 Tested according to specification : Specific gravity at 15.5" ... ... 0.8149 Distillation of 25 C.C. ... ... first drop at 125" C. 125 to 127-5 2-25 C.C. 127.5 to 130.5 91-25 C.C. 10 C.C. and 10 C.C. HCl ... clear colourless solution. 0.5 C.C. water produces turbidity. Final temperature . . . ... ... 131' Polarization Blank Gerber ... faint trace of layer. . . . 2.58" in 200-millimetre tube [ a ] , r= 1.61'. DISCUSSION. Mr. RICHMOND, in reply to a question put by the President, said that in the sample referred to the proportion of petroleum was, they had concluded, somewhere about 1 per cent. This conclusion was baeed, not only on the figures given, but also on the amount they had been able to separate by fractional distillation. He had, however, heard of a sample containing 4 per cent. of petroleum.

ISSN:0003-2654    

DOI:10.1039/AN905300077b

出版商:RSC    

年代:1905

数据来源: RSC

摘要:

THE ANALYST. 79 THE DETECTION AND ESTIMATION OF SMALL QUANTITIES OF MALTOSE IN THE PRESENCE OF DEXTROSE. BY JULIAN L. BAKER, F.I.C., AND W. D. DICK, F.1 C . (Read at the iMeeting, November 2, 1904.) LAST year the Council of this Society honoured us by suggesting that we should submit L. Grimbert's method for detecting small quantities of maltose in presence of dextrose ( J o z L ~ . Pharnz. Chim., 1903, xvii., 225, and this Journal, 1903, 151) to a critical examination. Lepine and Boulud (Comptcs Red. SOC. Biol., December, 1901) devised a method for detecting dextrose in presence of maltose which consisted in treating the phenyl osazones of these sugars with ether. It was claimed that maltosaeone was dissolved and could be recognised by its crystalline form. Grimbert (Zoc. cit.), however, stated that maltosazone is as insoluble in ether as dextrosazone. He recommended the following method as capable of detecting maltose in a 0.1 per cent.solution containing 0.1 to 1 per cent. of dextrose : 20 C.C. of the solution containing the two sugars are treated with 1 C.C. of phenylhydrazine and 1 C.C. of glacial acetic acid, and the whole heated on the water-bath for an hour, and then cooled. The mixed OsStzones are washed with cold water and dried, then washed with benzene until the washings are colourless, and dried at 100" C. They are then triturated in a mortar with the smallest possible amount of acetone diluted with its own volume of water, and, on allowing the filtrate to stand, crystals, with the characteristic form and melting- point (196q to 198" C.), are deposited.Or, the osazones may be heated in a minute amount of water for five minutes on the water-bath, and then rapidly filtered, leaving ihe dextrosazone, which is much more insoluble in hot water, on the filter. I n the course of this investigation we employed freshly distilled phenylhydrazine80 THE ANALYST. and pure maltose and dextrose. To test Grimbert's method systematically, pure specimens of maltosazone (melting-point, 195' to 200°C.) and dextrosazone (melting- point, 200" to 202" C.) were prepared and the relative solubilities examined in different solvents. Solveil t . Boiling water . . . ... Ether &ij ... Benzene 9 7 Toluene ... Xylene ... Chloroform ... Acetone ... 50 per cent. aqueous acetone (cold) 20 per cent.aqueous acetone 7 7 10 per cent. aqueous acetone ,, ... 9 , 9 9 9 7 9 7 MaltoBazone. Completely soluble Slightly 7 7 7 7 7 7 > 7 7 7 9 7 7 7 7 ' ? ' Very 7 7 7 , 7 7 Fairly 7 7 Slightly ? 7 Des trosazone. Slightly soluble. 9 7 7 7 7 9 9 7 7 7 7 , 7 7 9 , 9 , 7 7 Fairly ,, Slightly ,, Insoluble. Insoluble. I t will be noticed that 50 per cent. aqueous acetone dissolves dextrosazone to some extent, and, therefore, throughout these experiments we used 20 per cent. acetone. The solubility of pure maltosazone in benzene, in our opinion, precludes the use of this solvent for removing the tarry matters produced during the formation of the osazones, for it was found that when a prepared mixture of the pure osazones of maltose and dextrose, in which the former was present in small quantity, was washed with cold benzene the maltosazone was for the most part dissolved. Moreover, the solubility of the impure osazones of maltose and dextrose, such as results when the mixed sugars are converted into osazones, is very marked in cold benzene.This portion of Grimbert's process had to be abandoned, and we endeavoured to prepare the osazones in such a manner that the tarry products of the reaction were reduced to a minimum. Clean osazones may be obtained by heating 20 C.C. of 5 per cent. solution of the mixed sugars contained in a round-bottomed flask fitted with a tube condenser with 1 gramme of freshly distilled phenylhydrazine and 1.5 c.c.of 50 per cent. acetic acid for three-quarters of an hour in a boiling water-bath. The osazones are then cooled and filtered through a Gooch crucible, washed with 25 C.C.of cold water, and then with 10 C.C. of cold 5 per cent. aqueous solution of acetone. When the preparation is well drained, it is mixed in the Gooch crucible with 10 to 15 C.C. of cold 20 per cent. acetone, and filtered. On standing, the filtrate deposited a mixture of maltosazone and a little dextrosazone. The former, if present in sufficient quantity, could be easily identified, when examined under the microscope with a i-inch or +-inch objective, by its characteristic ribbon-like crystals. Working under these conditions, dextrose, when mixed with 15 per cent. of maltose, gave definite indications of maltosazone, 10 per cent. of maltose was doubtful, and no satisfactory separation of maltosazone could be obtained when dextrose was mixed with 24 and 5 per cent.of maltose. When mixtures of the pure osazones of maltose and dextrose were made in varying proportions and triturated with 20 per cent. acetone, it was easy to detect 5 and 10 per cent. maltosazone in the filtrate. This illustrates the influence whichTHE ANALYST. 81 the by-products of the osazone reaction has on the crystalline structure of maltosa- zone, and this would be still more marked if the sugars themselves were impure. The difficulty of preparing pure maltosazone from the products of the hydrolysis of starch is well known. Attempts were made to estimate the amount of maltose in a mixture of this sugar and dextrose by converting into the osazones in the manner described above.After washing with the 25 C.C. of cold water the osazones were dried until constant in weight in the water-oven, and then washed with 20 C.C. of cold 20 per cent. acetone. The osazone was again dried and weighed, and it was hoped that when working under these standard conditions the difference in weight due to the loss of maltosaaone might be a measure of the maltose present. The results were very variable, and, after many trials, we were forced to the conclusion that no process of estimation could be based on the difference in solubility in 20 per cent. acetone of maltosazone and dextrosazone. We next tried to see if it was possible to estimate small quantities of maltose by acid hydrolysis. Numerous experiments were carried out to determine the proper conditions for the inversion of maltose.When 10 C.C. of a 2 per cent. solution of maltose are heated in a flask fittsd with a tube condenser with 1 C.C. of strong hydrochloric acid (specific gravity 1.16) and 10 C.C. of water for ninety minutes in a, boiling water-bath, the contents of the flask being then cooled and neutralized, the inversion wag completed to the extent of 96-5 per cent. As the object of the investi- gation was to estimate small quantities (from 24 to 15 per cent.) of maltose in presence of dextrose, this amount of uninverted maltose would be without any marked influence on the results. Moreover, under these conditions there were practically no reversion products formed. Having obtained the inversion constant for maltose, mixtures con- taining known amounts of maltose and dextrose were made, the gravity of the solu- tion of the mixed sugars was taken, and the gramines per 100 C.C.calculated by the 3.86 divisor. Ten c.c., or other appropriate volume, of the sugar solution was then weighed and the solid matter present calculated. The reducing power in terms of dextrose was determined before and after inversion. The percentage of maltose found was calculated from the formula : (R-R1) x100, 100 - 62.1 M = in which R and R, are the reducing powers in terms of dextrose after and before inversion respectively. The constant 62.1 is the reducing power of anhydrous maltose, dextrose being taken as 100. Approximate Per- centage by Weight of added Maltose t o Dextrose. Reducing Power in ternis of Dextrose before Inversion.Reducing Power in terms of Dextrose after Inversion. Percentage of Maltose found. 2.5 5.0 10.0 15.0 99% 97.9 96.5 94.07 100.1 100.15 100.2 100.1 1.3 5.9 9.9 15.882 THE ANALYST. These results, which are the mean of many determinations, are fairly satisfactory, for it will be clear that a very small experimental error in the determination of the reducing powers will seriously affect the percentage of maltose. If maltose and dextrose are the only sugars in the mixture which is being analysed, the inversion method will afford fairly accurate results; but should any other body be present, capable of forming reducing sugars on hydrolysis (dextrin, for example), the difference in the reducing powers before and after inversion would be calculated as maltose.Since the number of reactions which can be utilized for the estimation of maltose in presence of dextrose is very limited, we decided to see if anything could be done by employing yeasts of selective fermentative functions. Hansen and other investigators have shown that certain yeasts, amongst them Saccharomyces Ma~xia~zus and Lzdzuigii, possess the property of fermenting dextrose and not maltose. We employed Is. Marxianus. It was obviously necessary to ascertain (1) if the culture of S. JIa~xiaizz~s would have any reverting influence on dextrose, and (2) if a maltose hydrolyzing enzyme was present. Three hundred C.C. of a 1 per cent. solution of dextrose to which some yeast extract had been added were fermented for five days at 2.5" C. The remaining sugar had the constants ( u ) D ~ .~ ~ = 52.1 and R~.S,, = 97.8 per cent. dextrose (corrected for added yeast extract). Two hundred C.C. of a 1 per cent. solution of maltose was treated with S. Ma~xianus under similar conditions. At the end of five days the solution, which had undergone no change in concentration, had the constants (u)D y.!13 = 134.5, and R3.93 = 101.2 per cent. of maltose. The two possibilities, therefore, have no foundation, hence it was perfectly safe to use the culture of 5'. Mai*xia~zz~s for the removal of dextrose from a mixture of that sugar and maltose. The method of experiment was as follows : To 100 C.C. of a 2 to 5 per cent. solution of the mixed sugars 5 C.C. of sterile yeast extract (prepared by boiling washed brewery yeast with water and filtering) were added, and the solution infected with a pure culture of 5'.Mcuxiaizus and allowed to ferment for five days at 25" C. At the end of this time the solution was treated with a little alumina cream, filtered, boiled to remove the alcohol, and its gravity, specific rotatory power, and reducing power in terms of dextrose determined. About 60 per cent. of the dextrose was fermented. The undermentioned results were obtained : Before Fermentation. Constants of Mixtures of' varying Proportions of Maltose and Dextrose. y- , -L \ After Fermentation. R,.,, glucose (4 D,'M R,.,, glucose 34.7 (4 D3.60 56.5 97.3 11 1.3 59.1 96.6 88.0 63.1 56.4 97.4 82.0 '70.0 56.4 97.4 108.5 37% (Fermented for sixty hours) (Fermented for sixty hours) The increase in the specific rotatory power and the marked drop in the reducing power after fermentation may be regarded as evidence of the presence of maltose.THE ANALYST.83 In order to confirm this deduction, the sugar remaining in solution was treated with phenylhydrazine acetate in the water-bath for three-quarters of an hour and the sma!l amount of dex trosazone formed removed by filtration. Maltosazone separated from the filtrate in all the above experiments, and after it was recrystallized from a small quantity of boiling water it had the characteristic ribbon-like appearance of maltos- azone and melted at 180’ C. The melting-point is low for maltosazone, but it is well known that a small quantity of dextrosasone considerably depresses the melting-point of the former. The conclusions that we have arrived at in this work may be summarized as follows : 1.L. Grimbert’s method (Zoc. cit.) for removing the subsidiary products of the osazone reaction by benzene failed to give satisfactory results in our hands owing to the solubility of the impure maltosazone in this solvent. A small quantity of cold 5 per cent. aqueous acetone removes most of the impurities, witbout to any great extent dissolving the maltosazone. By relying on the osazone reaction alone, it was only possible to detect quantities of 15 per cent. maltose in mixtures of this sugar and dextrose with any degree of certainty. 2. Unsuccessful efforts were made to estimate small quantities of maltose in presence of dextrose by converting into osazones, and dissolving the maltosazoue out with 20 per cent.acetone. 3. Small quantities of maltose, in a mixture of maltose and dextrose, may be estimated with a fair degree of accuracy by determining the reducing power before and after inversion under standard conditions, which are described. The difference in reducing powers may be due to maltose, but, in order to be certain on this point, the solution of the mixed sugars is fermented with S. Ma.l-xianzcs. A rise in the specific rotatory power and fall in the reducing power is additional evidence of the presence of maltose. To place the matter beyond doubt, the solution after fermentation is converted into maltosazone, and this compound identified as such by its micro- scopical appearance and melting-point. Should dextrinous bodies of high molecular weight be present in the solution to be analysed, they must be removed before the inversion and fermentation. This may be done by repeated precipitations in alcohol, or mixtures of alcohol and met one.The methods described above are being used by the authors in an inveatigation on the products of the acid hydrolysis of starch. DISCUSSION. The PRESIDENT (Mr. Fairley) having invited discussion, Dr. THORNE said that, when this set of carbohydrates occurred together in a mixture, even their identification, not to mention their determination, was a very dificult problem, towards the elucidation of which the author’s work was certainly an important step. It seemed to him, however, that dextrin, if present, would cause a difficulty in the fermentation process, quite as great as that which, as stated in the paper, it caused in the reduction process, He must say that he had not found84 THE ANALYST.fermentation processes altogether satisfactory. I n his experience, the supposition that a given yeast fermented a substance completely, or left another substance entirely unfermented, did not work out in practice to anything like the full degree. The author’s own experience in the two days’ fermentation experiment showed that in that case the dextrose had not been completely fermented, and the maltose was not left absolutely intact. Although with mixtures of dextrose and maltose numbers could be obtained which were approximately correct, it seemed to him that, if dextrin were present, and especially if cane-sugar were also present, the inter- ference of these products would make even the identification of small quantities of maltose very difficult, if not doubtful.Possibly the authors might have something to say with regard to the influence of dextrin and of cane-sugar, if present, on these fermentation results. Mr. CHAPMAN said that this communication was of special interest, inasmuch as it represented the first fruits of a scheme which had been adopted by the Society with the object of fostering and promoting investigation in connection with analytical chemistry, and of securing the revision of processes which on the face of them seemed likely to be useful to practising chemists, but which for one reason or another could not be justifiably accepted without some further examination.If the future communications to the Society under this scheme were as useful and as well carried out as the one to which they had just listened they would have reason to congratu- late themselves on having conceived the idea of such a scheme. Mr. Baker had remarked that he and his colleague had, to use his own expression, ‘‘ gone beyond their commission” ; but they would be very glad if others would also ‘‘ go beyond their commissions ” with as good results as the present authors had. So far as this paper was concerned, he (Mr. Chapman) must confess that he would have liked to have heard a little more about the acetone method, particularly as to its ability to detect, say, a small quantity of dextrose in the presence of a comparatively large quantity of maltose.Perhaps the authors had some further results bearing on this point. He thought there couid be no doubt that the adoption of these three methods and a careful consideration of the results obtained would enable the one sugar to be estimated in presence of the other with a fair degree of accuracy. With regard, however, to the fermentation process, it must be borne in mind that the employment of a pure culture of any organism was apt in unpractised hands to be followed by misleading results. It was well known how prone such cultures were to become impure, and even a slight contamination might after a little time become serious. Those who were accustomed to working with pure cultures knew how to check their purity and to ascertain whether they had become contaminated, and they knew, also, what those unaccustomed to such matters might, perhaps, not know, namely, how necessary it was that such checking should be systematic.The detection of contamination was much more difficult than in the case of a chemical reagent, and could, practically speaking, only be carried out by those who were constantly handling such pure cultures. I n short, the biological method was in many cases very useful ; but it was apt to be dangerous in inexperienced hands. With regard to other points raised in the paper, he had found the reducing power of maltose in terms of dextrose to be distinctly lower than 62, and also that the melting-point of maltosazone was lower than the authors had found. He had purified maltosazone over and over againTHE ANALYST.85 from every liquid from which it would crystallize, and had never been able to get the melting-point as high as 202". Mr. BAKER, in reply, said that in the case of products consisting presumably of maltose, dextrose and dextrin, it was suggested that the dextrin should be first removed by precipitation with alcohol, or acetone, or a mixture of the two. With a mixture of maltose, dextrose, and cane-sugar, the cane-sugar should be inverted by yeast at about 55" C., and then fermented by S. Mayxianus. I n response to Mr. Chapman's desire for further information about the treatment of the osazones with acetone, he might say that after some experiments it had been found that dextrosazone was very appreciably soluble in 50 per cent. acetone, and by a process of reduction it was found that much better results were obtained with 20 per cent.acetone, in which dextrosazone wits practically insoluble. Mixtures of maltose and dextrose had been made containing 20, 5, 10 and 15 per cent. of maltose, and it was found that, extracting with 20 per cent. acetone, a mixture of 10 or 15 per cent. of maltose in presence of dextrose could be detected, but not 24 or 5 per cent. When the osazones were first isolated and then mixed, these smaller quantities could be detected, but it was not possible when the sugars themselves were mixed, owing to the formation of subsidiary reaction products. Another point to which attention might be drawn was that in the original method of Grimbert the benzene used removed practically all the maltosazone when this substance was present in small amount. With 15 or 10 per cent. of maltose it did not matter, but with 2; or 5 per cent. the method could not be used. Mr. Chapman's remarks on the use of biological reagents were perfectly just, but, as had been pointed out, practically no strong evidence of the presence of the maltose was to be obtained by inversion, and some other method was absolutely necessary. The only one applicable in the present instance, so far as he was aware, was the use of a, biological reagent-namely, S. Marxianus. In sugar analysis it seemed that such unusual reagents must sometimes be resorted to, but he quite agreed that it was well to recognise their danger in unaccustomed hands. The melting-point of maltosazone depended a good deal upon how the determination was made. If the sulphuric acid was heated very slowly, the maltosazone invariably melted at about 190" C. If it were heated quickly, according to Fischer's instructions, pure maltosazone would melt at 195" to 200" C, His own practice was to take the melting-point when the sintered mass ran together, and under those conditions he found the melting-point of pure maltosazone to be 195" to 200°, and that of dextrosazone 202" C. Mr. CHAPMAN : With dextrosazone it is much sharper than with maltosazone? Mr. BAKER: Yes.

ISSN:0003-2654    

DOI:10.1039/AN9053000079

出版商:RSC    

年代:1905

数据来源: RSC

摘要:

86 THE ANALYST. ABSTRACTS OF PAPERS PUBLISHED IN OTHER JOURNALS. FOODS AND DRUGS ANALYSIS. The Detection of Foreign Fat in Milk. G. Quesneville. (Ann. de Chimi. anal., 1904, ix., 457, 458.)-Assuming the correctness of the theory that the fat globules in milk are surrounded by an albuminoid envelope, the author has looked for a solvent that would dissolve fat without acting upon this albuminoid envelope, and has found benzene (boiling-point, 81' C.) suitable for the purpose. On shaking the cream (80 to 110 c.c.) separated from a litre of milk with 100 C.C. of benzene purified by recrystallization, and evaporating 50 to 80 C.C. of the extract, a residue corresponding to 0.2 to 0.5 gramme (at most 1 gramme) of fat will be obtained from a litre of milk containing 40 to 45 gramrnes of butter fat.If, on the other hand, the cream from a milk in which 15 grammes of butter fat have been replaced by 15 grammes of foreign fat be treated in the same way, a large residue of fat will be left. Thus, in one experiment in which the cream was shaken with 150 C.C. of benzene, 110 C.C. of the clear supernatant layer evaporated, and the residue dried a t 90" to 95" C. ; the extracted fat weighed 9 grammes, corresponding to a total amount of 13 grammes dissolved by the 150 C.C. of the benzene. Similar results were obtained with boiled milk, not more than 1 gramme of fat per litre of milk being extracted by benzene from the cream. C. A. M. A Simple Method for the Determination of the Fat in Butter. A. Hesse. (&it. Unterszcch. Nahi.. Geizzissmittel, 1904, viii., 673-675.)-The method is a modifi- cation of Gottlieb's process for the determination of fat in milk (ANALYST, 1898, 259).From 1.5 to 2 grammes of the well-mixed sample are weighed out into a stoppered cylinder and melted by the addition of about 8 C.C. of hot water. If necessary, the cylinder may be placed in hot water to complete the melting. One C.C. of ammonia and 10 C.C. of alcohol are now added, and the cylinder shaken until the proteids have dissolved. After cooling, the mixture is first shaken with 25 C.C. of ether and then with 25 C.C. of petroleum spirit. As soon as separation has taken place, the ethereal layer is pipetted off, 50 C.C. of ether are added to the cylinder, and pipetted off without shaking up. The contents of the cylinder are finally shaken with 50 C.C.of a, mixture of equal parts of ether and petroleum spirit, and the ethereal layer is once more removed with a pipette. The united ethereal solutions are evaporated, and the residue of fat weighed. I t is clainied that the latter contains no non-fatty matters. From the results given the method appears to be trustworthy w. P. s. The Molecular Weight of the Non-volatile Fatty Acids of Dutch Butter. A. Olig and J. Tillmans. (Zeit. Uv,terszbch. Nahr. Genussmittel, 1904, viii., 728- 730.)-The results of analyses of Dutch butters, churned from the milk by the authors themselves, are given, showing that in the summer the molecular weight of the non- volatile fatty acids generally, but not always, lies within the limits mentioned by .Juckenack and Pasternack (ANALYST, 1904, 156).I n the autumn, however, theTHE ANALYST 87 molecular weights were often above 261.0, the highest value obtained being 271.6. The results show, further, that this determination is not by itself a trustworthy method of detecting adulteration in butter fat. W. P. s. The Cryoscopic Method for Distinction of Genuine from Artificial Butters. A. Quartaroli. (Stnx. Sperim. Byrarein ItaZ., 1904, xxxvii., 18 ; through Clzenz. Zed. Rep., 1904, xxviii., 354.)-The author uses glacial acetic acid in place of the benzene recommended by Garelli for this method. Five to six grammes of dried filtered butter are shaken with 50 C.C. of glacial acetic acid, and allowed to stand for twenty-four hours. The solution is then filtered and the depression of the freezing-point determined.With fresh genuine butter the depression was 0.54 to 057 per cent. ; old samples gave 0.52 to 0.53 per cent., while margarine showed only 0.17 to 0.20 per cent. A mixture of 20 per cent. of margarine in butter reduced the freezing-point 0.36 per cent. H. A. T. The Composition of Fresh Almonds. F. Coreil. (Am. de Chim. nnnl., 1905, x., 21-23.)-Three specimens of the green fruit had the following composition : Hard. Semi-hard. Soft. l'er Cent. Per Cent. Per Cent. Bark ... ... ..- ... 87-00 83-00 81.10 Tegument of the nut ... 3-20 4.60 3 -55 Edible part (cotyledons) .' ... 9.80 12-40 15.35 The edible part consisted of the following constituents : Per Cent. Per Cent. Per Cent. Water ... ... ... ... 7-53 10.006 11-61 Solids ...... ... ... 2.27 3.394 3.74 Fat ... . . . ... ... 1.247 1.370 2.109 Mineral matter ... ... ... 0.142 0.158 0.210 Cellulose and carbohydrates 0-804 0.776 1.288 -- -- _- Nitrogenous substances ... ... 0.077 0.090 0.133 Phosphoric acid ... 0.038 0.046 0.059 ... . . . ... C. A. N. The Influence of Ozone on Wheat Flour. K. Brahm. (Xeeit. Untersziclz. iVa7zr. Genzwsmzttel, 1904, viii. , 669-673.)--As ozone, or ozonised air, is occasionally used to bleach wheat flour, the author carried out a number of experiments, in which he determined the alterations which flour undergoes when thus treated. When allowed to act for less than one hour, the ozonised air produced but little change in the physical and chemical characters of the flour, but imparted an " ozone taste " t o it, which did not disappear on heating the flour to 100" C.Prolonged bleaching .(several hours) considerably decreased the quantity of gluten yielded by the flour, although the total nitrogen remained the same, showing that it was only the physical properties of the gluten which had been altered. This was confirmed by mixing the flour, both treated and untreated, with yeast, water, salt, etc., as irf bread-making, and allowing the dough to " rise " at a temperature of 30" C. The flour which had been strongly bleached had very little '' rising " power. Bread made from ozonised88 THE ANALYST. Ro. flour was poor in appearance, of a yellow colour, pasty consistency, and unpleasant taste. Bleaching by ozonised air is therefore considered to have an injurious effect on the flour as regards the suitability of the latter for bread-making.W. P. S. Density. Determination of Commercial Glucose in some Saccharine Products. A. E. Leaeh. (Massachusetts State B0ai.d of Health, 35th Amual Rep., 1903, GO, 61.)-If the invert polarization at 87" C. of a sample of honey, jam, molasses, or syrup be divided by the assumed factor for the polarization of commercial glucose, the percentage of the latter is obtained. Several precautions are, however, to be con- sidered in carrying out the method. The direct polarization is obtained on a normal solution of the sample in the usual manner. For the invert reading a second solu- tion is prepared by dissolving 13.024 grammes of the sample in about 70 C.C. of water, adding 7 C.C. of concentrated hydrochloric acid, heating the mixture to 68" C., and cooling.A few drops of phenolphthalein are then added and enough sodium hydroxide to neutralize the solution. This neutralization is necessary to prevent inversion of the maltose and dextrin in the glucose at the high temperature of reading. After discharging the pink coloration by the addition of a drop of dilute hydrochloric acid, the usual clarifying agent is added and the whole made up to B. Invert Reading a t 22" C . a volume of 100 C.C. tively. commercial (American) glucose : Readings of this solution are taken at The following table shows the readings obtained C. Invert Reading a t 87" c. 22" and 87" C. respec- with five samples of 153-4 154.6 165-4 162.8 171.0 146.6 149.0 159.4 155.0 161.2 1 2 3 4 5 A.Direct Reading. 42"B. 42" B. 42" B. 43" B. 45"B. 156.6 158.6 169.6 167.4 174.0 Average . . . . . . . . , Eatio of c to B. 0.956 0.964 0.964 0.952 0.943 0.956 Ratio of C to A. 093G 0-940 0-940 0.926 0.927 0.933 I t will therefore be necessary in the case of jam, etc., to divide the reading at 87" C. by 93 per cent. of the assumed polarizing value of commercial glucose (for example, 175)-thstt is, by 163-in order to express the results in terms of the latter. w. P. s. The Detection and Estimation of Citric Acid in Wines. L. Robin. ( A m . de Chim. anal., 1904, ix., 453-456.)-Twenty-five C.C. of the wine are heated to the boiling-point, mixed with 3 C.C. of a 40 per cent. solution of neutral lead acetate, and the boiling continued for one or two minutes. The precipitate is then allowed to subside, and the liquid filtered while still hot.The precipitate, consisting of lead sulphate, phosphate, tartrate, and citrate, is washed with warm water, and heated for five minutes at 90" C. with 10 C.C. of water acidified with acetic acid.THE ANALYST. 89 The liquid is decanted on to a, filter, and the filtrate and washings containing the tartrate and citrate of lead are saturated with hydrogen sulphide and filtered. This filtrate is evaporated nearly to dryness in a porcelain dish, the residue dissolved in 5 C.C. of 90 per cent. alcohol, and the solution exactly neutralized with potassium hydroxide, and then acidified with 0.5 C.C. of glacial acetic acid, and thoroughly mixed. The liquid is transferred to a small flask, and the dish washed twice with 5 C.C.of 90 per cent. alcohol and 0.5 C.C. of glacial acetic acid. The flask is left for an hour in a cool place, during which time the potassium bitartrate will have been deposited, while the citrate is kept in solution by the acetic acid. The liquid is filtered, the filter washed with acidified alcohol, and the filtrate shaken with 5 or 6 drops of a saturated solution of cadmium acetate. If citric acid had been added to the wine a flocculent precipitate is obtained. For a quantitative determina- tion, the cadmium citrate is collected on a weighed filter, washed with 90 per cent. alcohol, and dried for two hours at 100" C. The weight multiplied by 0.5738 and then by 40 gives the amount of citric acid in a litre of the wine. Denigh' qualitative test (ANALYST, xxix., 118) has not given satisfactory results in the author's hands.C. A. M. The Nitrogenous Constituents of Flesh. M. S. Grindley. (Joumz. Amei'. Chcin. Xoc., 1904, xxvi., 1086.)-The elaborate results recorded in this paper are a preliminary step towards the elucidation of the chemistry of the proteids as they exist in meat used for food. A uniform method of analysis was followed, the meats being successively extracted with the following liquids in the order named : Cold water (up to 10" C.) ; 10 per cent. sodium chloride solution; 0.15 per cent. hydro- chloric acid ; 0.15 per cent. caustic potash solution ; and boiling water. I n each solution determinations of the total nitrogen, coagulable proteid, albumoses (by precipitation with zinc sulpbate), peptones (by precipitation with bromine water), and flesh bases, were made.After the extraction treatments with these solvents the following amounts of insoluble proteid matter were found in the final residues : Lean beef, raw, 0.71 and 1.34 per cent. ; lean beef, boiled, 18-69 per cent. The author calls attention to the fact (previously noticed by Van Slyke and others) that loss of nitrogen occurs in using bromine as a precipitant for peptones, since this reagent decomposes the flesh bases and similar nitrogenous bodies, with liberation of free nitrogen, I t is also found that bromine does not precipitate all the proteids completely from a solution. The cold-water extracts of raw flesh invariably contain a small amount of nitrogen existing in the form of ammonia, or ammonium salts, even after previous removal of these by distillation with barium carbonate.As a result of his experiments, the author draws the following conclusions : 1. I t is evident that a considerable proportion of raw flesh is soluble in colcl 2. The data show that 12-14 per cent. of the total proteids of raw flesh were 3. Of the total nitrogen in raw meats, 22 per cent. was soluble in water. 4. The nitrogen existing in cold water extracts of raw meat is equally divided water . soluble in cold water. between proteid and non-proteid substances.90 THE ANALYST. 5 . The acidity of a solution of flesh increases upon the coagulation of its proteida. 6. The proteids of cooked meat are much less soluble than those of raw flesh in cold water and 10 per cent. sodium chloride solution, 7.Cold water extracted 3.06 per cent. of nitrogenous matter from raw meats and only 0.27 per cent. from boiled meat. 8. A 10 per cent. solution of sodium chloride extracted from raw meats 6-10 per cent. of proteid matter, and only 0.5 per cent. from boiled meat. 9. A 0.15 per cent. solution of hydrochloric acid dissolved from raw meat 2.28 per cent. of proteid, and from boiled meat 2.30 per cent. 10. A 0.15 per cent. solution of caustic potash extracted from raw meats 2.88 per cent., and from boiled meat 4-84 per cent. of proteid. 11. Hot water removed from raw meats 0.49 per cent., and from boiled meat 6.24 per cent. of proteid matter. 12. Of the total proteid existing in the original raw meats, 95.22 per cent, was dissolved by successive treatment with the above-mentioned reagents, while only 50.59 per cent.of the total proteid of the boiled meat was soluble. The paper is illustrated by a large number of tables of analyses, for which the original must be consulted. The author hopes to publish shortly the results of his work on the separation and purification of the different proteids of flesh. A. R. T. The Solubility of Different Caseins in Pepsin-Hydrochloric Acid. A. Zaitschek and F. v. Szontagh. (Pjliiq. A ~ L . , 1904, civ., 550-563 ; Biochena. Ceizt~albl., 1905, iii., 411, 412.)-In a series of parallel digestions for seventy-two hours at 38” C. it was found that the crude caseins of human milk and of mare’s and am’s milk were entirely dissolved by pepsin-hydrochloric acid, whilst only 8 per cent.of cow’s milk, 14 per cent. of buffalo’s milk, and 15 per cent. of goat’s milk were respectively digested under the same conditions. These results were also confirmed in experiments with the purified caseins. C. A. Ill. Determination of Sulphur and Phosphoric Acid in Foods, etc. J. A. LeClerc and W. L, Dubois. (Jozm. Anze~. C h e w SOC., 1904, xxvi., 1108.)-The following methods were used for the determination of these substances in foods, fzeces, and urine, in connection with the experiments of Dr. Wiley and Dr. Bigelow on the influence of preservatives in food on the human body. Determination of Sulplmv and Phosphorus in Foods and Fmes.--(l) About 1 to 12 grammes of the dried and finely-ground sample is placed in the cartridge of the Parr calorimeter (Jouwz.Amer. Chem. Xoc., xxii., 646), 10 to 15 grammes of sodium peroxide added, and the cartridge closed and the contents thoroughly mixed by shaking. The, mixture is ignited by means of a red-hot iron wire introduced through the valve, the cartridge being meanwhile immersed in cold water up to its narrow part. Combustion takes place immediately, and, after cooling, the contents of the cartridge are dissolved in hot water, acidified with hydrochloric acid, and the excess of sodium peroxide decomposed by boiling. I n the case of foods, the filtered liquid is made91 THE ANALYST. up to 200 c.c., and 50 C.C. of the solution taken for the phosphoric acid determination (see (3) below) ; the remainder is precipitated with barium chloride.In the analysis of faeces, the liquid, after acidification, is made up to 300 c.c., and 50 C.C. taken for the determination of phosphoric acid (3). The remainder of the solution is treated with ammonia, to remove the phosphates, before determining the sulphate. This precau- tion is advisable, since phosphates are otherwise liable to become occluded with the barium sulphate. 2. The Osborne method is tedious and somewhat uncertain. TO 10 C.C. of water in a nickel crucible of 100 C.C. capacity are added about 10 to 12 grammes of sodium peroxide, avoiding excess, and then 4 grammes of the meat or other fresh food, or 2 grammes of dried food or faeces. The water is largely evaporated on a water-bath, and the mixture then heated over a low flame, increasing the heat cautiously.Much frothing takes place, and the froth should not become ignited. The heat is further increased, when the frothing has subsided, until the mass begins to fuse, when, after cooling, a little more sodium peroxide is added and the mixture re-heated. This is continued until no more action takes place, and oxidation is complete. The mass is then dissolved, boiled, and diluted, etc., as already described in (1). The Parr calorimeter method would be preferable, but the cartridge is so small that sufficient sample cannot be taken. One holding 2 to 3 grammes is desirable, and a more practicable process than that of Osborne would then be available. 3. For the determination of phosphoric acid in the liquid obtained by either of the foregoing processes, the official method (Bzireaib Chemistry, Dept.of Agric., B d . xlvi., revised, p. 14) is employed, except that the solution is precipitated cold, and allowed to stand overnight at the ordinary temperature. The precipitate is finally washed until no trace of acid is present, when it is titrated as usual. Determiization of Sulphur ayzd Plzosphoms i i z Uq%ze.--(a). The sulphur is determined by Osborne’s sodium peroxide method, already described. A little less water and peroxide than before and 20 C.C. of urine are employed, and the mixture evaporated on the water-bath. The mass is then gently heated, and the method subsequently continued as in the case of foods, etc. (2). Very little frothing should occur. (b) The phosphoric acid in urine is determined by the usual titration method with uranium acetate, using potassium ferrocyanide as an outside indicator.Fifty C.C. of urine are diluted to 150 C.C. with water before heating and titrating. Undiluted urine was found to give low resulta. A. R. T. Detection of Artificial Colouring Matters in Mustard. W. Schmitz- Dumont. (Zeit. ofentl. Chem., 1904, x., 487.)-While agreeing that the tests given by Bohrisch (ANALYST, 1904, 372) are usually sufficient to detect the presence of aniline colours in mustard, the author points out that samples coloured with dyes of the tropeolin type behave like genuine mustard when tested by Bohrisch’s method. The dyed wool should always be moistened with hydrochloric acid, when, if tropzolins be present, the brownish-yellow colour of the wool changes to bright red or violet.w. P. s.92 THE ANALYST. Determination of the Cold-Water Extract yielded by Ground Ginger. A. McGill. (Canadian Inland Revenue Dept. Bztll., xcv., 24, 25.)-The following method is described, and has for its main feature the mechanical agitation of the ginger with the solvent. Five grammes of the sample are dried in the water-oven until constant in weight, which usually takes about twelve hours or more, The dry sample is then transferred by means of a dry funnel to a centrifugal tube of about 150 C.C. capacity and treated with 100 C.C. of water. After closing, the tube is placed in a horizontal shaking apparatus for thirty minuhes and then in a centrifugal machine for ten minutes. The clear supernatant liquid is poured through a tared filter, and the insoluble residue again treated with 100 C.C.of water, shaken, whirled, and the clear solution passed through the filter. Finally, the residue is washed on the filter with about 100 C.C. of water, the exact quantity being immaterial, as only traces of soluble matter remain in the residue. The filter and its contents are dried at a tem- perature below 50" C. for a few hours, and afterwards at 90" to 95" C. until dry. Genuine samples of ground ginger yield about 19 per cent. of cold-water extract by this method, an amount which is considerably higher than that obtained by the usual method of extraction. w. P. s. Flowers of Sulphur and Sublimed Sulphur. A. Domergue. (Joeir72. Plzarm. Chim., 1904, xx., 493-499.)-The condensed vapours of sulphur are known indifferently as either flowers of sulphzir or szibliwzed szdphzw, but in the author's opinion there should be a differentiation between the two names for commercial products. At the commencement of the condensation tho difference in temperature between the sulphur vapour and the atmosphere of the chamber leads to the sudden formation of a globular form of deposit, whilst at a later stage the powder is crystalline.The author suggests that the former should be termed flowers of szdphzw, whilst sulphur containing variable proportions of the crystalline and globular forms should be sold as sublimed sulphur. The microscope affords a means of distinguishing between the two qualitatively, and a quantitative test may be based on the proportion insoluble in carbon bisulphide.Various commercial products examined by the author con- tained from 13 to 33 per cent. of insoluble sulphur, while samples taken direct from the chamber contained from 25 to 37 per cent. The conclusion arrived at by the author from these results is that the name $towers of s?dphzLr ought to be reserved in commerce for those products giving at least 33 per cent. of sulphur insoluble in carbon bisulphide at the time of manufacture, whilst other products of the condensation chamber should be termed sublimed szdphzw. C. A. 31. Physical Characteristics of Adrenaline. G. Bertrand. (Bull. SOC. Chim., 1904, xxxi., 1289-1292.) - Pure adrenaline forms crystals arranged in rosettes round common centres. At 20" C. the amount dissolved is 0,0268 per cent., whilst at 100" C.its solubility is somewhat greater. It is still less soluble in alcohol, and is insoluble in ether, chloroform, carbon bisulphide, and petroleum spirit. Adrenaline is optically active, the mean rotation found by the author being [a]D = - 53.5". I t does not show a sharp melting - point. When thrown in a fine powder on to a Maquenne's block it only melted instantly when It is only slightly soluble in water.THE ANALYST. 93 the temperature was about 263" C., and the same result was obtained after further purification of the alkaloid (cf. ANALYST, xxx., 22). C. -4. M. New Colour Reaetions of Cryogenin. (Ann. de Chi.11~. anal., 1904, jx., 456, 457.)-(1) Cryogenin (m-benzamido-semicarbazide) gives a chestnut- brown coloration with potassium permanganate. (2) On heating a few dry crystals of cryogenin in a test-tube over a spirit-lamp a brownish-black coloration is produced, whilst the liberated vapours have a strong ammoniacal odour.(3) A brilliant garnet-red coloration is obtained on treating crystals of cryogenin with a drop of pure sulphuric acid and a drop of potassium bichromate solution. C. A. M. G. Pe'gurier. Characters of Santalol and Sandal-wood Oil. Seidler. (,4poth. Zeit., 1904, xix., 795 ; through Pharm. Journ., 1904, lxxiii., 813.)-Santalol, the active constituent of sandal-wood oil, has the following characters : Specific gravity, at least 0.980 ; optical rotation in 100-millimetre tube, - 18" to - 19'. It forms a clear solution with 4 parts of alcohol (70 per cent. by volume). Santalol distils almost entirely between 302" and 306".On acetylation, the product should require a definite quantity of caustic potash for saponification. Pure East Indian sandal-wood oil has a pale yellow colour, and only a slight odour of sandal-wood. I t s specific gravity is 0.975 to 0.985, and optical rotation - 17" to -19" for 100 millimetres. The oil dissolves in 5 parts of 70 per cent. (volume) alcohol. The acid number, ester, and saponification numbers do not exceed, in pure samples, the limits 2.75, 5 (at the most), and 7-5 respectively. The saponifi- cation number of the acetylated oil is at least 197. The oil distils mainly between 297" and 305'. A. R. T. Composition of Pine Oils. J. Trtjger and A. Beiitin. (Archiv. der Pharm., ccxlii., 521 ; through Pharm. Jozinz., 1904, lxxiii., 900.)-The oils distilled from the young shoots of Pinzis sgZvestris and Pinz~s strobzu contain dextro - pinene and laevo-pinene respectively in large proportion, but are free from sylvestrene, cadinene, and the borneol esters which are present in the oils from the older leaves. These bodies are therefore produced during the later growth of the leaves. A. R. T. Fixed Oil of Carthamus Tinctorius Fruit. G. Fendler. (Apoth. Zeit., xix., 721 ; through Pharm. J o u ~ . , 1904, lxxiii., 900.)-This fruit, obtained from Gerinan East Africa, yields 25-82 per cent. of fixed oil. The separated kernels of the seeds yield 50.37 per cent. of a slow-drying oil having the following characters : Specific gravity at 15' C., 0,9266 ; melting - point, + 5" C. ; Reichert - Meissl number, 0 ; acid number, 11.63 ; saponification number, 191 ; iodine value, 142.2 ; and refractometer reading at 40" C., 65". The oil becomes cloudy at - 13", and is not wholly solid at - 18" C. The fatty acids of this oil have the following characters : Specific gravity at 15' C., 0-9135 ; melting-point, 17" C. ; freezing-point, 12" C. ; acid number, 199; mean molecular weight, 281.8; acetyl number, 52.9; and iodine value, 148.2. The liquid fatty acids have an iodine value of 150.8, and a mean molecular weight of 293.1. ,4. R. T.

ISSN:0003-2654    

DOI:10.1039/AN9053000086

出版商:RSC    

年代:1905

数据来源: RSC

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94 THE ANALYST. TOXICOLOGICAL ANALYSIS. The Detection of Poisons in the Ashes left after Cremation. C. Mai and H. Hurt. (Xeit. aizgezo. Chem., 1904, xxvii., 1601-1605.)-Experiments were carried out to ascertain whether arsenic, mercury, or cyanogen compounds could be detected in the ashes left after cremating the bodies of animals which had been poisoned with these substances. Dogs and rabbits were employed, and the bodies were burnt in a brick furnace heated by coal. Arsenic was readily detected in the ashes, the greater quantity being found in the bones. Mercury salts, such as the perchloride and cyanide, completely disappeared during the cremation, and the ashes were free from this metal. With regard to cyanogen, it was found that cyanogen compounds are not formed when flesh is burnt, and, further, that these compounds cannot be detected in the ashes of animals poisoned The latter was practically free from arsenic.with potassium cyanide or prussic acid. w. P. s. On the Presence of Arsenic in the Body and its Secretion by the Kidney. W. Thomson. (Proceedings Mcmchestei. Literayy and Philosophical Society, 1904-5, xlix., 1, 10.)-Having found that the urine of people living in Manchester contained arsenic, the author extended his researches in order to discover, if possible, the source of the contamination, and, further, to ascertain how rapidly arsenic is eliminated from the body. Six samples of urine from patients in the Manchester Southern Hospital all contained arsenic, the quantity varying from i$Gc to i& grain per gallon. The latter quantity was in the urine of a woman who had been in hospital thirteen days, and who had taken no medicine during that time.Five samples from people living at St. Helens, where large quantities of arsenic escape into the atmosphere from the glassworks, contained from T$c to %kc grain of arsenic per gallon. The quantities present in six samples from Swansea varied from 7$G to &grain per gallon, and in five samples froiii Sheffield from T&c to -ibTi grain per gallon. Samples obtained from St. Anne’s-on-the-Sea and the Hebrides, where the air was not likely to be contaminated, were either quite free from arsenic or practically SO. Six samples of inilk purchased in or near Manchester all contained arsenic, the quantity present ranging from less than i&c to & grain per gallon.A piece of beefsteak grilled over a coke fire was found to contain not more than 3$cc grain of arsenic per pound even in the outside portions. Four different brands of cigarette- paper were next examined. All were arsenical, the amounts varying from i+vG to 3+c grain per pound. With regard to the elimination of arsenic by the kidneys, an experiment was carried out in which +G grain of arsenious acid was administered to a man. Previous tests showed the quantity of arsenic in his urine to be i+Gc grain per gallon. All the urine passed was collected and tested. Seven hours after taking the dose the amount of arsenic had risen to 2c grain per gallon. At the end of twenty-three hours about 16 per cent. of the quantity taken had been secreted, and after forty-seven hours the urine contained only i$uc grain per gallon, which was the quantity present previous to making the experinlent, A human thyroid gland, weighing about 18 grammes, was found to contain onlyTHE ANALYST. 95 EL minute quantity of arsenic, T;Gc grain per pound, so that arsenic can scarcely be spoken of as a constituent part of this gland, as it has been stated to be by Gautier. The spleen, liver, heart-muscle, kidney, and rib-bone of the same body were free froin arsenic, but the lung contained & grain per pound, and the hair i$ grain per pound. w. P. s.

ISSN:0003-2654    

DOI:10.1039/AN9053000094

出版商:RSC    

年代:1905

数据来源: RSC

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THE ANALYST. 95 ORGANIC ANALYSIS. Colour Reactions of Certain Alcohols and Hydroxylated Bodies. G. Guerin. (Jourrc. Pharm. Chim., 1905, xxi., 14-17.)-0ne C.C. of the alcohol under examination is mixed with 5 or 6 drops of a saturated aqueous solution of furfural, and the mixture shaken with an equal volume of concentrated sulphuric acid. In the case of solid substances, a little is dissolved in sulphuric acid or in ethyl alcohol, and the solution cautiously treated as described. Or a little of the substance may be mixed on white porcelain with 4 or 5 drops of sulphuric acid and a drop of the aqueous solution of furfural. No colour reactions are given by methyl or ethyl alcohols, and a brown or brownish-violet coloration is simply due to the action of the sulphuric acid on the furfural, and may be neglected.The following colorations were obtained in this test : Normal propyl alcohol, deep violet ; secondary propyl alcohol, reddish violet ; isobutyl alcohol, violet blue ; active amyl alcohol (methyl-ethyl-carbinol), violet ; amyl alcohol of fermentation, violet ; caprylic alcohol, reddish violet ; glycol, reddish violet ; propyl-glycol, violet purple ; glycerin, reddish violet ; ally1 alcohol, immediate brown coloration preceding almost immediate decomposition ; menthol (in ethyl alcohol solution), blue ; mannitol (dissolved in sulphuric acid), brownish green-in ethyl alcohol, brownish violet ; dextrose (in sulphuric acid or ethyl alcohol), brownish violet ; lactose, brownish ; malic acid, brownish violet ; tartaric acid, brownish violet ; cholesterol, blue (sensitive test) ; anthemol (from Aizthemis izobilis), blue ; phenol, reddish violet ; thymol, violet ; guaiacol (in ethyl alcohol), violet ; orcinol, blue ; hydroquinone, dark blue ; pyro- catechol, deep violet ; resorcinol, violet ; phloroglucinol, violet ; pyrogallol (in ethyl alcohol), reddish violet.C. A. M. The Volumetric Determination of Hydroxylamine by means of Trivalent Titanium. Stahler, (Berichte, 1904, xxxvii., 4732, 4733.)-The method is based on the reduction of the hydroxylamine to ammonia : Ti,03 + NH,O = 2Ti0, +- NH,. Titanium tetrachloride or sulphate is dissolved in sulphuric acid and reduced by means of nascent hydrogen until the solution attains the required reducing power, which may be determined by titration with potassium permanganate solution.During the final standardizatiolz with the permanganate solution a current of carbon dioxide is passed through the flask. I n the determination 4 grammes of hydroxyl- amine salphate are dissolved in 100 C.C. of water, 21 C.C. of the solution, diluted with boiling water, then rapidly mixed with an excess of the standard titanium solution, and the excess of titanium trichloride determined by titration with TG permanganate solution in a current of carbon dioxide. The method is also applicable to the deter-9 6 THE ANALYST. mination of organic hydroxylamine compounds, whilst hydrazine sulphate is not altered by titration with titanium trichloride under the sanie conditions. C. A. &I. A Reaction of Sugars containing the Aldehydic Group.A. Berg. (Bull. SOC. Chinz., 1904, xxxi., 1216-1217.)-Bromine in the presence of water oxidizes aldoses, converting the aldehydic into an acid group, with the formation of acids, such as gluconic, galactonic acids, etc. These acids give an intense yellow colorstioii with very dilute and slightly acid solutions of ferric chloride. On the other hand, ketoses are not converted into acids under the regulated action of bromine. In examining a sugar, from 0.02 to 0-03 gramme in the solid state or in concentrated solution is heated for ten minutes at 60" to 70" C. with 10 C.C. of a, freshly-prepared saturated solution of bromine. The liquid is then rapidly heated to the boiling-point to expel the excess of brotnine, and the colourless solution tested with 10 C.C.of a reagent prepared by adding t o 100 C.C. of water 4 drops of a solution of ferric chloride (45" BB., S.G. 1-45), and 2 drops of hydrochloric acid (22" BB., S.G. 1.17). Sugars not containing the aldehydic group give little or no coloration, and the slight coloration given by fructose and sorbose is to be attributed to the presence of traces of aldoses, which it is difficult to completely eliminate, A strong reaction is given by arabinose, xylose, glucose, and galactose. Of the complex sugars, bioses or frioses, those that do not reduce Fehling's solution give no reaction-e.g., saccharose, rafinose, trehalose, etc.-whilst those with reducing properties also give marked colorations. I n the case of polyoses it is necessary to use bromine water free from mineral acids-notably hydrobromic acid-in order to prevent inversion during the test, and it is for this reason that the bromine water should be freshly prepared from pure broDine.Commercial saccharose invariably gives a, more or less pro- nounced yellow coloration, due to the presence of a little glucose. The latter can be removed by recrystallizing the sugar several times from boiling alcohol, after which it no longer gives the reaction. C. A. hl. Determination of Nicotine in Presence of Pyridine. James A. Emery. (Jorwn. Qmer. C l z m . SOC., 1904, xxvi., lll3).-The author determines the proportion of total volatile bases in nicotine preparations by Kissling's process: and the amount of nicotine by the observation of the rotatory power o€ the solution. The difference gives the proportion of pyridine present, since the latter compound is optically inactive.Five grammes of tobacco extract, or 20 grammes of dry, finely-powdered tobacco are treated with 10 C.C. of a solution containing 6 grammes of caustic soda in 60 C.C. of 90 per cent. alcohol and 40 C.C. of water. Tobacco extracts are, in addition, mixed with sufficient pure dry calcium carbonate to form a moist, but not lumpy, mass. After thorough mixing, the whole is transferred to a Soxhlet apparatus, and extracted with ether for five hours. The solvent is next evaporated on a water-bath at a low temperature, care being taken that the last portions of the ether are not heated sufficiently to cause volatilization of the nicotine or pyridine. Fifty C.C. of decinormal caustic soda are now added to the contents of the flask, and the solution transferred to a distillation-flask (of 300 C.C.capacity) by means ofTHE ANALYST. 97 150 C.C. of water. The liquid is then distilled in a current of steam, in such a, manner that when about 450 C.C. of distillate are obtained, only 10 to 20 C.C. of liquid remains in the distilling-flask. The vapours should pass through a well-cooled condenser, the outlet-tube of which dips into a little water in the receiver. Bumping and frothing in the distillation-flask are avoided by the addition of a, little pumice-stone and a small piece of paraffin-wax. The distillate is diluted to 500 C.C. with water, and an aliquot part titrated with fifth- normal acid and methyl-orange. This is essentially Kissling’s process for the determination of the total volatile bases.Another portion of the distillate is placed in a polarimeter-tube, and its rotatory power determined. A 1 per cent, solution of pure nicotine is also prepared, and its rotation noted (the specific rotation of pure nicotine at 20’ C. is - 161-55O) ; whilst it is also titrated to determine accurately its exact strength. Thus the value of one degree on the polarimeter scale can be ascertained in terms of percentage of nicotine, and if the percentage found be multiplied by 5, the amount of nicotine in the whole of the distillate will be obtained, If, then, the nicotine found be expressed in ternis of standard acid, and the number of C.C. be subtracted from the volume of standard acid required to neutralize the entire distillate, a fairly accurate determination of the pyridine present can be made.The following rapid method, for the determination of nicotine only, avoids the extraction with ether : A known weight of the sample is made alkaline with 50 C.C. of decinormal caustic soda, and distilled exactly as already described, after dilution with 150 C.C. of water. The nicotine in the distillate is then determined by the polarimeter. This method gives good results generally, except that in tobacco- powders slightly low results are obtained, owing to the difficulty of sufficiently reducing the volume of liquid in the distilling-flask without causing bumping of the wet powder in the flask. All the nicotine will then have passed over. The test-analyses given are very satisfactory.A. R. T. On the Separation of Fatty Acids. W. Frahrion. (Zed. angezl;. Clzem., 1904, xvii., 1482-1488.)-1t is here shown by experiments described in detail that Partheil and FcriB’s method of separating saturated and unsaturated fatty acids (ANALYST, xxix., 51) is unreliable. Although the lithium salts of unsaturated acids by themselves are completely soluble in 50 per cent. alcohol, yet in the presence of the lithium salts of saturated fatty acids (including lithium acetate) they become partially insoluble. On the other hand, the lithium salts of saturated acids are by no means insoluble in 50 per cent. alcohol, and their insolubility is still further reduced by the presence of lithium salts of unsaturated acids. Hence, in the precipitation of a mixture of fatty acids a condition of equilibrium results, to which the relative quantities and molecular weights of the different acids, the amount of precipitant, the concentration of the solution, and the temperature all contribute. C.A. M. The Detection of Rosin and Fish Oils in Boiled Linseed Oil. W. Lippert. (Chem. Rev. Fettyh. Harz lizd., 1905, xii., 4, 5.)-Linseed oil boiled with lead or manganese oxides gives only brownJ colorations in Storch and Morawski’s test, whilst red or blue colorations are obtained when resinates, rosin, or fish oils are present.98 THE ANALYST. Maize oil also gives a similar reaction. Four years ago the high price of linseed oil led to extensive adulterations, and oil expressed from heads of sardines was largely exported from the coast of Spain for this purpose.Samples of such oil examined by the author gave the Storch-Morawski and other reactions for fish oil. After exposure of the oils to the light, the reactions were fainter, and after a year could no longer be obtained, though cetyl alcohol (melting-point 50" C.) could still be isolated. I n the author's opinion the Storch reaction is, therefore, not conclusive of the purity of an oil when no coloration is obtained, although it should not be omitted in the qualitative examination of boiled linseed oil. C. A. 31. The Detection of Sesame Oil in the Presence of Certain Dyestuffs. G. Fendler. (Chem. Rev. E'ettfb. H u r x - I d , 1905, xii., 10, 11.)-Baudouin's test cannot be applied with certainty in the case of fats containing certain dyestuffs that give a red coloration with hydrochloric acid.I n such cases the following modification of Soltsien's test (ANALYST, 1903, xxviii., 298) is recommended. The fat is treated with twice its volume of benzene and half its volume of the stannous chloride solution, and the test-tube placed in a bath at 40" C. until the tin solution separates, after which it is transferred to a bath at 80" C., where it is kept at such a depth that the level of the water outside is not above that of the stanuous chloride solution inside. The heating is continued until the red coloration no longer increases in intensity. I n the absence of sesame oil the coloration caused by thedyestuffs soon disappears, and the stannous chloride solution remains colourless after further heating. C.A. M. Differentiation of Cotton-seed Oil from Kapok and Baobab-seed Oils. E. Milliau. ( A m . de Chim. anal., 1905, x., 9, 10.)-Kapok and baobab-seed oils reduce silver nitrate and give Halphen's reaction with greater intensity than even cotton-seed oil, A means of distinguishing them from the latter is based upon the fact that the fatty acids of kapok and baobab oils, after being washed and dried rapidly at 105" C., cause a strong reduction of a 1 per cent. alcoholic solution of silver nitrate even in the cold, whereas the fatty acids of cotton-seed oil do not effect appreciable reduction until heat has been applied. The fatty acids from kapok oil or baobab oil, mixed in the proportion of 1 per cent. with olive or other oils, give a dark-brown reduction after about twenty minutes, when 5 C.C.are thoroughly shaken with 5 C.C. of the solution of silver nitrate in absolute alcohol, and allowed to stand. On the other hand, the fatty acids from mixtures of olive oil with 10 to 50 per cent. of cotton-seed oil give no coloration under the same conditions. C. A. M. Birch-leaf Oil. (Hueizsel's Report ; through Pharm. J o u m , 1904, lxxiii., 900.) -Birch leaves yield 0.049 per cent. of an olive-green, optically inactive essential oil, containing 43 per cent. of a stearoptene. The oil, which liquefies at 35" C., and is soluble in warm alcohol, has a specific gravity of 0.9074 at 30" C., an ester number of 99, and a saponification number of 146.7. When freed from stearoptene, a thick oil of acid reaction remains of specific gravity 0.8732 at 20" C.A. R. T. Tests for Wood Tar Pitch. B. M. Margosches. (Clzein. Eeu. Fett 21. HCW- Id., 1905, xii., 5-9.)-The samples of pitch examined were derived from beech-wood99 THE ANALYST. tar, and had the following elementary composition : Bosnian pitch, C63.0 and H6.0 per cent.; and Hungarian pitch, C66.0 and H10.0 per cent. Wood tar pitch is thus richer in oxygen than other artificial “ asphaltums.” The behaviour of wood tar pitch with certain solvents affords a means of distinguishing it from the other artificial products. Thus, on treating 0.1 to 0.3 gramme with 10 to 15 C.C. of carbon bisulphide the liquid remains colourless for some minutes, and only acquires a faint yellow coloration after twenty-four hours at the ordinary temperature or at 30” C.Petroleum spirit is a still more characteristic reagent, for it remains colourless after standing in contact with the pitch for twenty-four hours, although it dissolves about 2 per cent. of the substance. Davies found that from 16 to 24 per cent. of wood tar pitch was soluble in that solvent, and the author attributes the discrepancy to the fact that more volatile products are now expelled during the distillation of the wood tar. Chloroform dissolves wood tar pitch in considerable quantity, yielding a dark brown solution, Alcohol and ether dissolves much less, and the solutions only turn yellow after some time. The Hungarian pitch only imparted a slight coloration to benzene, but the Bosnian pitch coloured the liquid yellow in five minutes, the colour changing to red after twelve hours.C. A. M. The Differentiation of the Different Forms of Nitrogen in Glue. S. R. Trotman and J. E. Hackford. (Jozwn. SOC. Clzewz. Id., 1904, xxiii., 1073.)- In addition to the determination of water and mineral matter, the authors consider that an analysis of glue should include determinations of the total nitrogen, nitrogen precipitated by zinc sulphate, and subsequently by bromine in the filtrate. Physical tests they consider to be in general unreliable. The authors proceed by analytical methods very similar to those which have been previously applied to the valuation of glue, etc., by A. H. Allen (Conzm. Org. AnaZysis, vol. iv., 1898). A. R. T. A Contribution to Rubber Analysis. W. Esch and A. Chwolles. (Gummi.Zeitung, 1904, xix., 125 ; through Chem. h i t . Rep., 1904, xxviii., 354.)-The author considers that the factor 100 : 97.5 in Henriques’ formula is not invariably correct. This factor depends very largely on the solvent used for extraction, also on the nature of the caoutchouc in question and the method of vulcanization employed. Hot acetone is better than ether (Henriques) for the extraction of the unsaponifiable matter, as ether dissolves appreciable quantities of caoutchouc. H. A. T. Mineral Constituents of Sumac. S. R. Trotman. (Journ. SOC. Chem. hzd., 1904, xxiii., 1137.)-Whilst it is of the greatest importance that sumacs should con- tain a due proportion of tannin, it is also desirable that a limit of ash should be fixed. The presence of sand and iron in sumac is actively deleterious, the former to the grinding machinery and the latter to the goods, which may become stained.Com- mercial sumacs, having an ash of 6 to 9.5 per cent., generally contain distinct, amounts of iron removable by the magnet, sometimes 0.25 per cent. By moderate winnowing it is easy to obtain a sumac showing ash, 6.5 per cent.; silica, 0.75 per cent. ; iron, 0.15 per cent. The winnowing process removes much silica, iron, etc. The combined iron in sumac is not more than 0.1 per cent. Adulteration of100 THE ANALYST. sumac leaf with the stems does not cause any rise in the proportion of mineral matter. A. R. T. The Detection of Indoxyl (Indican) in Urine. G. Denigbs. (BzdZ SOC. Pharm., Bordeaux, September, 1904. Ann. de Chiwa. ct~zaZ., 1904, ix., 459, 460.)- Four C.C.of the urine are treated with basic lead acetate, then with 3 C.C. of hydro- chloric acid (specific gravity, 1.17 to 1*18), 1 C.C. of chloroform, and a drop of a solution of potassium chlorate (5 grammes per litre). The tube is shaken, and after the addition of a second drop of the potassium chlorate solution, aliowed to stand. If the chloroform is colourless or only slightly blue, indican is absent or only present in normal quantity. But if the chloroform has a pronounced blue colour, excess of indican is present. I n such cases the liquid should be shaken with another drop of potassium chlorate and allowed to stand, and this treatment repeated until the colour of the chloroforrn does not increase in intensity after the addition of a fresh drop of the reagent. The coloration is proportional to the amount of indoxyl in the urine, the indoxyl being oxidized into ‘ I hemi-indigotin,” which is readily soluble in chloroform, in which respect it differs from commercial indigotin. C. A. 11. Laboratory Methods. C. Goldschmidt. (Chem. Zeit., 1904, xxviii., 1229.) -Tin dust, which is a more eflicient reducing agent than many others, can be most conveniently prepared by allowing solutions of a tin salt to stand in aluminium vessels. For the preparation of mono- and di-methylaniline the following method is recommended : Formaldehyde acts on aniline, forming anhydro-formaldehyde-aniline, C,H ,NCH, and this compound, by reduction with tin dust and hydrochloric acid, yields mono methylaniline. Treating this with formaldehyde and subsequent reduction, dimethylaniline is obtained. H. A. T.

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DOI:10.1039/AN9053000095

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年代:1905

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100 THE ANALYST. INORGANIC ANALYSIS. A Method for Detecting the Presence of Certain Metallic Oxides. C. R. C. Tichborne. (Scient. PTOC. Royal Dzib1i.t~ SOC., 1904, x., 331-334.1-The test proposed is based upon the fact that most metallic oxides react with a solution of sodium hydrogen carbonate, a certain quantity of sodium carbonate being formed. The presence of the latter may be ascertained by the addition of a little phenol- phthalein. The solution of sodium hydrogen carbonate is prepared by dissolving 10 grammes of the pure salt in 100 C.C. of water. A few drops of a normal solution of nitric acid are added, as the solution alone will probably give a faint pink coloration with phenolphthalein owing to slight dissociation of the salt, The substance to be tested is triturated with a few cubic aentimetres of this solution and filtered.If any of the oxides specified be present, the filtrate will be alkaline in reaction towards phenolphthalein. Red lead, mercurous oxide, cupric oxide, ferric oxide, manganese dioxide, and alumina give no reaction ; whilst litharge, silver oxide, mercuric oxide (yellow and red), cuprous oxide, bismuth oxide, stannie oxide,101 THE ANALYST. antimony trioxide, ferrous oxide, manganous oxide, and zinc oxide readily decompose the sodium hydrogen carbonate. w. P. s. The Determination of Tin, Antimony, and Arsenic in Ores and Alloys. Henri Angenot. (ZeiL. angezo. Chem., 1904, xvii., 1274.)-Essentially the author’s method consists in completely decomposing the ore or alloy by a single fusion with sodium peroxide, and separating tin and arsenic from antimony according to Rose’s method. A.G. L. The Detection of Ferrous Salts in the Presence of Ferric Salts. L. Blum. (zeit. anal. Clzem., 1905, xliv., 10, 11.)-The well-known reaction for nitric acid cannot be applied conversely in the ordinary way for the detection of ferrous salts. For on adding sulphuric acid to a solution of ferrous sulphate, and then pouring nitric acid on to the surface, so much heat is produced as to prevent the formation of the brown colour. This is obviated by introducing a large crystal of potassium nitrate instead of the nitric acid. When a ferrous salt is present, red streaks changing to brown form round the periphery of the crystal, and the coloration does not disappear for several hours.C. A. M. The Detection of Tin in the Stannous Condition. L, Blum. (%&it. amZ. @hem., 1905, xliv., 10-l2.)-The reaction for detecting ferrous salts (see preceding abstract) can be used indirectly for the detection of stannous salts. If a solution of, say, stannous chloride, containing hydrochloric acid, be treated with ferric chloride, a corresponding quantity of ferrous chloride is formed ; and on adding to the solution an equal volume of concentrated sulphuric acid, cooling the mixture, and introducing a crystal of potassium nitrate, the characteristic red to brown coloration will be produced. C. A. M. Estimation of Phosphorus in Calcium Carbide. Hj. Lidholm. (Zeit. angezo. Chem., 1904, xvii., 1452.)-The author found that in Gall’s process a, sndden evolution of CO, would cause the loss of part of the contents of the crucible; and when this was remedied by the employment of a large crucible he found it was not practicable to completely decompose the powdered carbide with the nitre.H e therefore evolves the acetylene from the carbide with the aid of alcohol, which can be done suffi- ciently slowly to feed a burner with the gas. The following is the ap- 500 C.C. capacity, with a neck 50 millimetres wide, fitted with a three-holed stopper, which carries a, tube for passing hydrogen ( b ) , a reflux condenser (c), and a dropping funnel (cl). The tube b I + paratus used: a is a flask of about -- - - - __ - - - - -~-102 THE ANALYST. is somewhat bent, to enable a crucible ( e ) to stand on the bottom of the flask.The reflux condenser is connected by a tube (glass or indiarubbw) with the burner f, the jet being so fine that the acetylene flame does not become smoky. Surrounding the burner is a glass cylinder (9) 32 centimetres long and 5 centinietres wide, which is continued above as a glass tube about 5 millimetres wide. This tube passes down into a wash-bottle (i), iR there expanded into a long bulb (h), perforated with several apertures. The second tube from the wash-bottle is connected with a powerfut filter-pump. Ten gra,mmes of the powdered carbide are weighed into a crucible, which is then placed on the bottom of the flask, and the apparatus is put together, as shown in the diagram. Hydrogen is passed through the tube b, and when the air in the apparatus is expelled the hydrogen is lit, and at the same time the filter-pump is set in action.The condenser is then set in operation; from the funnel d about 30 C.C. of absolute alcohol are run in by drops, and afterwards about the !same amount of water is cautiously dropped in. Any phosphuretted hydrogen and organic phosphorous compounds mill be burnt to phosphoric acid, which will for the greater part be deposited on the walls of the cylinder. Any portion escaping from the cylinder will be completely retained in the wash-bottle. After the evolution of gas in the flask is fully completed HC1 is poured in t o dissolve the precipitated lime, and the contents of the flask are brought to the boil, so that all the phosphorus compounds are carried to the burner. When the gas has escaped from the burner for about ten minutes the stream of hydrogen is discontinued, and glass cylinder, connecting-tube, and wash-bottle are washed with warm ammonia into a beaker.This solution is filtered, to remove the silica, and finally the phosphoric acid is precipitated in the usual way with magnesia mixture. w. P. Note on the Chemistry of High-percentage Ferrosilicon. Haas. (StaM. ZL. Eiseqz, 1904, xxiv., 1315 ; through Chena. Zeit. Rep., 1904, xxviii., 353.)-Fifty per cent. ferrosilicon is completely soluble in cupric-ammonium fluoride, with deposition of metallic copper ; silicic acid does not appear to be separated. Eighty per cent. ferro- silicon is only slowly attacked. The effect of this solvent on carbon and phosphorus has not yet been examined.H. A. T. Note on the Amount of Moisture in Gases dried by Phosphorus Pent- oxide. (Jozwn. Amer. Chern. Xoc., 1904, xxvi., 1171.)-The author showed in 1887 that the combined amount of moisture and phosphorus pent oxide vapour remaining in a gas dried by means of this reagent is about 1 milligramme per 40,000 litres. Since then, greater precision in working has been attained, and it was found that 4,300 litres of gas retained only 0.1 milligramme of water plus phosphorus pentoxide. I n order to determine the water in this more accurately, 900 litres of hydrogen and oxygen were submitted to a very slow combustion (lasting a fortnight) in an apparatus designed by the author for the synthesis of water. As only 3 litres of the gaseous mixture entered the combustion chamber per hour, it was assumed that any volatilized phosphorus pentoxide would remain in contact with steam and water so long as to be completely absorbed. The $-litre of water thus obtained was collected (with due precautions), and, after being made Edward W. Morley.THE ANALYST. 103 alkaline with a very little sodium carbonate, was evaporated to about 5 C.C. The molybdate precipitate from this quantity was found, by comparison with standards, to be equal to about 0-02 milligramme of P,O,. This proportion is practically identical with the sum of the moisture and phosphorus pentoxide vapour as determined some years ago. Although small errors may somewhat affect these results, yet no gravimetric experiments need take into account the moisture in. a, gas dried by this substance. A current of gas passing at the rate of 2 litres per hour through 25 grammes of phosphorus pentoxide, in a properly filled drying-tube, contains much less than 1 milligramme of moisture in 40,c)OO litres, but whether the actual amount is 4 or :G milligramme cannot yet be stated. A. R. T.

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DOI:10.1039/AN9053000100

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年代:1905

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THE ANALYST. 103 APPARATUS. Use of a Mercury Cathode in Electrolysis. Ralph E. Meyers. (Jown. Anzcr. Chewz. Soc., 1904, xxvi., 1124.)-The author has extended the work of E. F. Smith (ANALYST, 1903, 372) to other elements. The beakers used in the electrolyses were of a form similar to those used by Smith, three sizes, holding 70, 45, and 35 cc., being employed. The procedure was substantially identical with that of Smith (Zoc. cit.), 70 to 80 grarnmes of mercury being used in each experiment. By the use of a mercury cathode, chromium can be accurately determined in slightly acidulated (sulphuric acid) solutions. The liquid, measuring about 70 C.C. , and containing about 4 drops of sulphuric acid, is electrolysed with a current of 0.4 ampire and 7.5 volts. The amount of chromium present should not greatly exceed 0.2 gramme.As the chromium amalgam readily decomposes water, it should be washed rapidly, and the alcohol used subsequently for this purpose should be fairly anhydrous. Chromium may by this method be separated from large or small amounts of aluminium, which latter may then be precipitated from the solution after electrolysis in the usual way. The strength of the current during the last hour or two should be increased (0.4 ampere to 0-8 ampire). Similarly, beryllium remains in solution, and the chromium may be deposited when in admixture with it. Iron may also be separated from beryllium in the same way. Molybdenum forms a brilliant white amalgam with mercury, and can be deposited from a, sulphuric acid solution of a molybdate, or from the acidified aqueous solution of molybdenum trioxide.Overnight deposition (fourteen hours) is usually resorted to, using a cnrrent of not more than about 1.5 to 2.0 amperes and 6 volts. A slight solvent action of the acid on the mercury, due to the heat evolved, is noticed if a stronger current be employed. About 5 drops of sulphuric acid for each 10 C.C. of liquid are added. I t is best to neutralize some of the acid towards the end, since too great acidity retards the deposition of the molybdenum. Vanadium may be separated from molybdenum by the a-bove method. Vanadium solutions turn blue, but no deposit occurs under these conditions. Thus the pure blue colour of the liquid shows when all the molybdenum has been deposited. Iron may be separated from vanadium by this method.Similarly, it is found that iron may be accurately separated from cerium, lanthanum, praseodymium, neodymium, and yttrium. The current employed is104 THE ANALYST. 0.8 amp&re and 6 volts, with 8 drops of sulphuric acid in the liquid. hours, or less, according to the iron present, is necessary for the electrolysis. anal. Chem., v., 627) was fully confirmed by the author. above methods of separation were very satisfactory. About fourteen The value of Drown and McKenna's separation of iron and aluminina (Joz~rn. The test analyses on all the A. R. T. New Apparatus for the Acoustic Determination of Vapour Density. (Chem. .&it., 1904, .xxviii., 869.)-The apparatus consists of zt steam-jacketed cylinder, or tube, in the lower end of which a standard metal whistle or reed is fixed.The whistle is connected by a rubber stopper or piece of tubing to the vapourising flask, and the whole can be lowered into a closed water-bath. For the determination of the vapour density of a liquid at looo C., 10 to 20 C.C. of the sample are brought into the vapouriser ; this is connected to the jacketed whistle, and when this and the bath are at 100' the whole is lowered into the water-bath. At once, or very shortly (according to the boiling-point of the substance), the internal pressure causes the whistle to sound, the note depending on the relative pressure of the vapour in the flask and that of the air. The note obtained is compared to that of a standard adjustable whistle, and the vapour density thus directly determined.The density of the vapour is to R. Wachsmuth. that of air practically inversely as the of the rate of vibration observed. The author gives exact formulae calculation of results, and describes the process in considerable detail. square for the The apparatus is obtainable from Messrs. Max Kaehler and Martini, Berlin, W. H. A. T. An Electrical Heater for Laboratories. S. R. Trotrnan and J. E. Hack- ford. (JOUWL Xoc. Clzem. I d , 1904, xxiii., 1137.)-This simple contrivance consists of a tin about 6 or 8 inches deep, of sufficient diameter to hold a lamp of 16, 32, or 50 candle-power. The exterior of the tin is covered with asbestos-paper. Ordinary type lamps are employed, but those which have become discoloured by long usage give the most heat, and these can be obtained at a small cost.The lamp is fixed through a hole near the bottom of the tin, and the whole apparatus is placed on a wooden base, the top surface of which, next to the tin, is covered with asbestos. The lamp is useful for saponifications, fat-extractions, alcohol and ether distillations, etc., the source of heat being quite constant and unaffected by draughts, while no ignition of inflammable vapours can take place. A. R. T.THE ANALYST. 105 A Simple Regulator for Use with Large Gas Burners. William H. Sodeau. (Journ. SOC. Clzem. Ind., 1904, xxiii., 1136.)-As shown in the figure, the regulator consists of a 16-ounce Bohemian glass flask, inside of which a glass tube (W) is placed, open at the top and closedat its lower end by a cork which rests on the base of the flask.The neck of the flask is closed by a rubber stopper carrying a tube (T) of the shape shown in the figure. The narrow (bottom) end of this tube reaches nearly to the cork in W. The middle portion of the tube T has a diameter of 11 millimetres, being 3 millimetres greater than the external diameter of I. The upper and wider part of T has a side tube (0), at which the connection with the burner is made. The top of T is closed by a cork carrying the tube I, through which the gas supply comes, the end of the tube being cut oft' obliquely, Two small holes (B), of 0.8 and 1.2 milli- metres diameter, allow the passage of sufficient gas to keep the burner lit in case the main gas supply is temporarily cut off by the regulator. Either of these holes may be blocked with soap if desired. To fit the regulator for use, the stopper is removed from the neck of the flask, which is then completely filled with methylated spirit heated to a temperature slightly higher than the regulator is likely to attain while in use. The stopper is then replaced, and sufficient mercury poured through the top of the tube T, as shown in the figure.The interior of the tube is dried by means of filter-paper. The regulator is next cooled to the temperature it is required to maintain, and the cork carrying the tube I placed in position in such a way that the end of the tube just touches the surface OE the mercury. If the temperature increases 1' C., the expansion of the spirit causes the mercury in T to rise 5 millimetres, sufficient to make a, great difference in the amount of gas passing.I t is desirable in the first adjustment to hang a small thermometer in the flask to accurately register the temperature of the spirit. I f the temperature falls I" C. too low, the tube I is raised about 5 inilli- metres, and proportionately in other caaes. The size of the regulator, which is very sensitive, may be largely varied according to requirements. A. R. T. An Improved Form of Crucible Lid. The lid is made slightly convex to the crucible, so that any liquid splashing on the lid, during effervescence or evaporation of the con tents of the crucible, drops back into the latter from the centre of the lid. The form of the lid does not in any way interfere with its general usefulness. It may be obtained from Messrs.J. J. Griffin and Sons, Limited, Sardinia Street, W.C. w. P. s. Material and Form of Rotating Cathodes. H. E. Medway. (.%its. ayzzo.1.g. Chem., xlii., 110.)-The author has tried to use silver and nickel crucibles as rotating cathodes instead of platinum crucibles (vide A m y . Journ. Sci., xv., 320). With silver good results were obtained in electrolysing copper sulphate solutions ;106 THE ANALYST. and on removing the copper by scraping it off as far as possible, and then treating with boiling hydrochloric acid, the loss in weight of the crucible was only 2 or 3 milli- grarnmes. With nickel, on the other hand, the results were not good, the error being about 1 per cent.; and on removing the copper with nitric acid, the loss in weight of the crucible varied from 6 to 32 milligrammes.Using rotating platinum discs as cathode, and a platinum wire bent around the edge of the disc in the form of a semicircle as anode (Shepherd, Jourrt. Phys. Chem., vii., 508), the author found that the deposits of copper obtained easily fell off the disc owing to unequal deposition. With an anode of foil under and parallel to the disc, on the other hand, good deposits were obtained, but the author prefers the use of a crucible. I t was found that aluminium discs (Hough, JOZLTIZ. Amer. Chewz. Xoc., XX., 302) could not be used. X. G. L. A Highly Sensitive Modification of Novy's Gas Regulator. William H. Sodeau. (Jozinz. SOC. C12em. Ind., 1904, xxiii., 1136.)-The ordinary forms of niercurial gas regulators are ill-adapted to requirements when marked fluctuations in the gas pressure take place, but by employing one with a larger bulb, containing a liquid of high expansibility, the defects are overcome.The modification shown in the figure has a cylindrical bulb (C) of about 15 to 20 C.C. capacity, (Any old-pattern regulator may be improved by cutting off the bulb and sealing on the lower portion of a Tollens gas regulator.) The inner tube (T) reaches nearly to the bottom of the bulb, and is con- tinuous with the stem above. The bulb contains toluene, or a hydrocarbon or alcohol of higher boiling-point, and a little mercury. The bore of the lower part of the stern should be of such width as to hold about 2 to 3 C.C. of mercury, so that no gas is drawn into the bulb when the regulator cools.The side-tube holding the screw-adjustment (A) should be inclined a t an angle of 20° to 30" from the horizontal, to retain mercury in the tube after cooling, otherwise a bubble of gas may be entrapped when the regulator is used again. The other details of the regulator remain unaltered. Since toluene has a coefficient of expansion about five times as great as that of mercury, and the capacity of the bulb has been increased ten times, this pattern of regulator will be about fifty times more sensitive than the ordinary form. If it is necessary to keep the bulb of the same diameter as the stem, still the substitution of toluene for mercury will give an instrument five times as sensitive. This regulator is very satisfactory for laboratory uee, and its efficiency is enhanced if a pressure regulator is attached to the gas-supply pipe.A. R. T. A Further Investigation of the Rotating Cathode. H. E. Medway. (Zciis. nnorg. Chem., xlii., 114.)-The author has applied the method previously described (A1iw.I.. Jozim. Sci., xv., 320) to other metals. A platinum crucible dippingTHE ANALYST. 107 into the liquid and rotating at a speed of 650 to 700 revolutions per minute was used as cathode. For cadmium, 0.2 gramme of cadmium sulphate was dissolved in 50 C.C. of water, and 10 drops of dilute sulphuric acid were added. A current of C.D.,,,)=5 and 6.6 ampi?res was used for fifteen minutes. Before stopping the current, the solution was made slightly alkaline with ammonia to avoid redissolution of the metal. For tin, 20 C.C.of a solution of stannous ammonium chloride, containing 0.08 or 0.16 gramme of tin, were mixed with 100 C.C. of a saturated solution of ammonium oxalate, and electrolysed with a C.D.,,, of 6.6 to 11.6 amperes for twenty or fifteen minutes. I n the case of x i m , 0.1 gramme of the metal as sulphate and 4 grammes of potassium oxalate were dissolved in 50 C.C. of water, and electrolysed with a current of 6.6 to 8.3 ampAres for twenty-five or thirty minutes. The presence of ammonium salts had a retarding influence on the deposition. I t was founC that the zinc could be directly deposited on platinum, and removed without injuring the latter. For gold, 25 C.C. of gold chloride, containing 0.07 gramme of gold, were treated with a large excess of potassium cyanide and 30 drops of strong ammonia and electrolysed, using a current of 1.8 to 6.6 amp6res for thirty minutes. I n all cases the results obtained were excellent. Five gold determinations showed a maximum error of 0*0001 gramme, with an average of =t0*00005 gramme. A. G. L. Vitro-Ink.-A non-corrosive ink for writing on glass, celluloid, etc., which will be found very handy for many laboratory purposes. After being properly applied it is insoluble in water, strong acids, and only very slowly by strong alkalies. We find that in order to obtain the best results it is necessary to rigidly adhere to the directions supplied with the ink. The makers are Messrs. J. Griffin and Sons. W. .J. S.

ISSN:0003-2654    

DOI:10.1039/AN9053000103

出版商:RSC    

年代:1905

数据来源: RSC

摘要:

THE ANALYST. 107 HIGH COURT OF JUSTICE. KING’S BENCH DIVISION. (li’roi)~ the ‘( Tintes ’’ of Satzwday, Pebrziary 4, 1905.) (Hefore the LORD CHIEF JUSTICE OF ENGLAND, MR. JUSTICE KENNEDY, and MR. ?JUSTICE RIDLEY.) BAYLEY v. COOK. THIS was a case stated by the Justices of Andover 011 an information laid by the appellant Bayley, an inspector under the Food and Drugs Acts, against the respondent Cook, for wilfully selling to the appellant, to his prejudice, milk not of the nature, substance, and quality demanded, being deficient in milk-fat to the extent of 68 per cent. I t was objected on behalf of the respondent that the analy&s certificate was defective, owing to its not stating the standard upon which it was based. The material parts of the certificate were as follows: ‘‘ I an1 of opinion that the sample contained the parts as under : Milk-fat, 1.4 per cent.; milk solids other than milk-fat, 5.6 per cent. Observations.-This milk is deficient in milk solids other than milk-fat to the extent of 2.9 per cent., which is equivalent to the addition of 34.2 per cent.108 THE ANALYST. of water. I t is also deficient in lnilli-fat to the extent of 53.4 per cent of the milk-fat.” The justices dismissed the summons on the ground that the certificate was bad. Mr. C. A. RUSSELL, K.C. (Mr. W. J. H. Brodrick with him), argued that the certificate was sufficient. Under Section 4 of the Sale of Food and Drugs Act, 1899, the Board of Agriculture had power to make regulations for determining what deficiency in any of the normal constituents of genuine milk should raise a presumption that it was not genuine.Rule 1 of the Sale of Milk Regulations, 1901, made under that section, was as follows : ‘‘ When a sample of milk (not being milk sold as skimmed or separated or condensed milk) contains less than 3 per cent. of milk-fat, it shall be presumed for the purposes of the Sale of Food and Drugs Acts, 1875 to 1899, until the contrary is proved, that the milk is not genuine, by reason of the abstraction therefrom of milk-fat or the addition thereto of water.” The certificate, taken in conjunction with this rule, was pripnd .facie evidence that an offence had been coiii- mitted. He cited “ Fortune a. Hanson” (1896, 1 Q.B., 202). The respondent did not appear. The LORD CHIEF JUSTICE, in giving judgment on Wednesday, said that he did not wish it to be thought that the provisions of the Act of 1899 in any way lessened the obligation upon the analyst as to what he was bound to state in the certificate by Section 18 of the Sale of Food and Drugs Act, 1876.If nothing more appeared than “milk-fat, 1.4 per cent.,” he doubted whether that would be a sufficient certificate. I t was necessary to show that the sample had been compared with some standard, and he gathered that that was what misled the justices, for they seemed to have thought that the basis on which the certificate was framed was not sufficient. It would have been more correct to state in the certificate what the proper quantity of milk-fat was, but, as a little examination would show, it did appear from the certificate, and it did correctly show how much milk-fat was deficient, and the standard of calculation could be gathered from the certificate itself, and therefore the objection to it was not a good one. Mr. JUSTICE KENNEDY, in agreeing, said that it was important that the accused should know without elaborate calculations what he was accused of, and he hoped that those who gave certificates would err, if at all, 011 the side of fulness and simplicity. Mr. JUSTICE RIDLEY agreed. The appeal was accordingly allowed and the case remitted to the magistrates.

ISSN:0003-2654    

DOI:10.1039/AN9053000107

出版商:RSC    

年代:1905

数据来源: RSC