摘要:

THE ANALYST. MARCH, 1888. LABORATORY NOTES. BY ALFRED H. ALLEN, F.C.S., F.I.C. (Read at the Meeting January 1888.) I. Alumina in Wheat.-The recent experiments of Yoshida (Jour. Chem. Soc., li., 748) and Young (ANALYST, xiii. 5), showing that alumina is a natural constituent of the ash of wheat, have rendered it desirable to see how far their conclusions modify the views hitherto held on this subject.42 THE ANALYST. In the discussion of a paper read by Mr. Wanklyn at the first meeting of this Society, I stated that “in my experience an allowance of 3 milligrammes per 100 grammes of bread, for phosphate of aluminium naturally present, is amply sufficient.” This would correspond to about -005 per cent. of aluminium phosphate in the flour. Mr. Jones said his experience confirmed mine absolutely.Dr. Dupre had met with as much as s o 0 9 per cent., and Dr. Stevenson agreed with him. Dr. Muter mentioned a case where the bread was made with salt containing alumina had met with nearly -010 per cent. Mr. Wigner was in the habit of allowing ,008 for phosphate of aluminium natural to the article. More recently it has been shown-I think by Dr. Duprh-that the alumina natural to flour bears more or less relation to the proportion of silica present, from which it may be inferred that the alumina exists wholly or chiefly as silicate, and hence is probably of extraneous origin. On the results of these experiments I based the statement in my ‘‘ Commercial Organic Analysis ” (vol. i., page 373), that ‘‘ it may be taken as a rule that from the amount of alum calculated from the total aluminium of the bread should be subtracted a weight equal to the silica found, when the difference will be approximately the true amount of alum added.” Thus if the total aluminium corresponded to -040 per cent.of alum, and the silica was *008 per cent., the corrected proportion of alum would be -032 per cent. Dr. James Bell considers that his experiments do not indicate any definite relation between the silica and alumina of flour, but his figures show that, broadly speaking, the alumina tends to follow the silica. The experiments of Yoshida, which appear to have been very carefully made, were conducted on cereals and leguminous plants grown on a soil of volcanic origin, remarkable for containing a large proportion of alumina soluble in hydrochloric acid.Under these circumstances, Yoshida found 2-62 per cent. of mineral matter in the whole wheat, and this mineral matter contained 0.106 per cent. of alumina, equivalent to 0.2536 per cent. of aluminium phosphate. Calculatedon the original wheat, this is 0.0066 per cent., or just about what was previously admitted to be normally present. Mr. Young comes to an exactly similar conclusion, obtaining from Vienna flour of the best quality, containing 0.7 per cent. of ash, 0.0075 per cent. of aluminium phosphate. All these amounts are so insignificant that they do not materially invalidate the dictum that “ flowering plants do not contain aluminium as a normal constituent,” though in strict accuracy, and in view of recent experiments, the words “ except in extremely minute proportions,” should be added.The practical interest attaching to the question exists in the fact that the proportion of alumina found to be naturally present in wheat confirms the justice of making a deduction of 7 or 8 grains of alum per 4 lb. loaf from the amount corresponding to the total aluminium found by analysis. I may here remind the members that i t has been raised as a defence for the presence of alum in flour that alum formed a leading constituent of the composition used for stop- ping the holes and cracks produced in millstones by wear. I may call the attention of those interested in the mode of existence of aluminium in bread and flour to a process I devised some years since, by which I obtained veryTHE ANALYST.43 encouraging results and rendered unnecessary the questionable correction for the aluminium existing as silicate. It consisted in effecting the solution of the starch by malt-extract, destruction of the resultant soluble carbohydrates by fermentation with yeast, acidulation of the liquid by nitric acid, followed by filtration, evaporation of the liquid, ignition of the residue, and precipitation of the aluminium as phosphate in the usual way. Before leaving the subject, I may add that if the results of the analysis of samples of flour and bread may be regarded as indicating the general character of the articles, adulteration with alum is practically obsolete in the districts for which I act as analyst. 11. Precipitat.ion, of Hop-Bitter by Lead Acetate.-At a recent meeting of the Society Dr.Johnstone read a paper which was published in the last number of the ANALYST, describing experiments from which he co~cluded that neither neutral or basic acetate of lead effectually removed the bitter principle from aninfusion of hops. As this view was opposed to my own experience, and that of all previous observers, except in a solitary instance mentioned by Dr. Muter, I suggested to Dr. Johnstone that we should both subject to the method the same sample of hops with a view of seeing whether the non- precipitation of the bitter by lead was in any way a consequence of his method of manipulating. In pursuance of this I examined a sample of hops which had been used by Dr. Johnstone in his experiments, and found that the treatment with lead in the manner prescribed by me did not remove the whole of the bitter.On the other hand, I sent a portion of a sample of hops which I had already submitted to the process with satisfactory results t o Dr. Johnstone, when curiously enough he failed to precipitate the bitter principle although I had succeeded perfectly. With a second portion of hops from the same source, though not strictly the same sample, he also found the process to fail, I n the case of this sample, therefore, there is a direct conflict of evidence, Dr. Johnstone failing to make the process to answer, whereas I had succeeded. But the fact that such an apparently simple operation could fail in the hands of another chemist seemed to me very serious, and I have consequently submitted to the process some eight or ten additional samples of hops.I n most instances the process has succeeded fairly well, though when operating on a considerable quantity of hops the residue has usually retained a slight but distinct bitter taste. I n one or two instances, however, the bitter- ness has been more strongly marked, ns, indeed, it was in the sample sent me by Dr. Johnstone. The experiments prove to my mind that precipitation with lead acetate cannot be relied on to remove all the bitter principle of the hop from all infusions containing it, especially when the delicacy of the method is increased by extracting the remaining traces of bitter with chloroform, instead of simply tasting the concentrated filtrate, 111. ATote on the Deterrniimtion of S'ulplmr in Oils.-I had occasion recently t o analyse a sample of blast-furnace creosote oil, in which I was desired to determine the proportion of sulphur.The quantity likely to be present was, of course, much smaller than is usually met with in organis substances containing sulphur as an essential con- stituent, and hence the ordinary processes of determining sulphur, employed in ultimate organic analysis, seemed scarcely applicable, as a considerable quantity of the substance, at least 5 grammes, would be required for the experiment. Oxidation with nitric acid44 THE ANALYST. __ ~ was for obvious reasons an unsuitable process, and the same remark applied to treatment with dry oxidising agents. Under these circumstances it appeared to me that the best plan would be to burn the oil in a suitable lamp, and estimate the sulphur in the products of combustion, just as sulphur is estimated in coal-gas. I was here met, however, with the difficulty that when burned from a wick the creosote oil produced intolerable quanti- ties of smoke, which could not be controlled and rapidly clogged the wick, whether of asbestos or cotton, thus bringing the experiment to an end.Various experiments in this direction were made until I decided to dilute the creosote oil with alcohol, hoping thus to obtain a better regulation of the combustion. With certain precautions this plan was found to answer, and ultimately the arrangement shown in the sketch was adopted. A purified methylated spirit was made by distilling the ordinary spirit of commerce from caustic alkali, and this was saturated with solid ammonium carbonate.5 grammes of creosote oil was then dissolved in 45 grammes of the spirit, and the whole placed in the lamp A, to the top of which the adapter C is fitted air-tight by means of a large bung. The upper end of the adapter is connected with a bent glass-tube passing nearly to the bottom of a vertical Liebig’s condenser filled with wet glass marbles and broken glass. The lower end of the condenser is fitted with a glass tap, and the higher tubulureTHE ANALYST. 45 is connected with a water-pump, or other aspirating arrangement by which a continuous steady current of air can be drawn through the apparatus. By preference a second Liebig's condenser, filled with glass beads, is introduced between the first condenser and the pump, but this is not really necessary. The apparatus being arranged, the spirit is ignited, when the combustion proceeds quietly, but the operation has to be conducted very slowly to prevent smoking, and it is desirable to cool the metal part of the lamp by wrapping round it copper gauze, as otherwise the alcohol vapour is liable to kindle with slight explosion, and tile lamp is extinguished.The water condensed in D, and which is tapped off at intervals into the flask F, of course contains all the sulphur of the creosote oil in the form of sulphate or sulphite of ammonium. It is treated with bromine water, acidulated, and the sulphur precipitated as barium sulphate in the usual way. I n this manner the particular sample of creosote oil for which the process was devised was found to contain -087 per cent. of sulphur, and on repetition by the same process *088 was found.In this cam the sample was mixed with an equal weight of ordinary kerosene, but instead of dissolving the carbonate of ammonium in the liquid it is preferable to suspend it over the flame in a small porcelain crucible. In this way a sample of rape oil was found to contain 0.017 per cent. of sulphur after making a correction for the sulphur in the kerosene oil with which it was mixed, which amounted to OQ00O014. A convenient plan of ascertaining how much of the oil has been consumed is to weigh the lamp before and after the experiment. DISCUSSION. Dr, VIETH said they had heard a very interesting communication from their President. In a laboratory where there was a variety of work there must always be curious results cropping up, and that was just the place to bring those results forward. If that were always done, their meetings would become yet more interesting, and perhaps more members would be induced to contribute papers.Mr. HEHNER said that with regard to the hop question he had intended to say a few words. He had also taken up the matter, and thought perhaps that a possible expla- nation of the difference in the results obtained by Dr. Johnstone and Mr. Allen was this-as there was no doubt that those two observers did get different results, and there should be some explanation-perhaps the quantity of acetate of lead used might be the cause, or the precipitate might possibly be more or less soluble in excess of lead solution.He made an extract from pure hops himself, and added various quantities of lead acetate, removing the excess of lead with sulphuretted hydrogen, and evaporating to dryness, and in all cases he got a residue which was distinctly bitter ; also on precipita- tion with basic acetate one could taste the bitter, but if the liquid was not evaporated to complete dryness, a bitter taste could not be perceived. I n no case had he shaken out with chloroform and ether. He thought that the difference greatly arose from the fact that the test had been made rather too delicate, and that it was advisable to avoid evaporation to dryness, or to a very small bulk. Dr. JOHNSTONE said that he got the bitter out of the beer-not out of the hops.With regard to alumina in flour, a discussion took place in the Chemical News some time ago upon the supposed finding of copper in bread. Dr. Edmonds wrote to that journal drawing attention to the blue colour which occurs very often. Other writers made some reply, and then the matter dropped. IIe had obtained the same results, and I have also used the same process for determining the sulphur in rape oil,46 THE ANALYST. examining the blue colour found it was due to phosphate of iron-vivianite, in fact. Mr. HEHNER said that whenever he had tested flour €or copper he had always found copper. Mr. ADAMS said that he had made a number of experiments in the hop question, and had never failed to get rid of the bitter when it was due to hops, but perhaps that arose from his not having carried his experiments so far as Mr. Allen had done, He (Mr. Adams) made a decoction, and treated it with basic acetate of lead, threw down the lead finally by sulphuric acid, which was quicker than sulphuretted hydrogen, and then reduced the bulk from half a pint to about half an ounce, and in every case with that quantity he couldalways taste foreign bitter, while that of the hop had entirely disappeared. He did not know whether that explained Mr. Hehner's results, where he only carried his evaporations to a fluid state, and not dryness. With regard to the detection of bitters, there was only one that failed him, and that was camomile, the bitter of which, like hops, was precipitated by acetate of lead. Mr. ALLEN said that the direct tasting of the concentrated aqueous liquid was doubtless a less delicate method of recognising a bitter principle than agitating the liquid with ether or chloroform, and tasting the evaporated chloroformic or ethereal solution. It appeared probable that the evaporation of a solution containing more or less free sulphuric acid would tend to decompose any trace of hop-bitter which had remained unprecipitated by lead."

ISSN:0003-2654    

DOI:10.1039/AN888130041c

出版商:RSC    

年代:1888

数据来源: RSC

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46 THE ANALYST. ON THE COMPOSITION OF MILK AND MILK PRODUCTS. BY DR. P. VIETH., F.C.S., F.I.C. (Read at the Meeting, February, 1888). WHAT I wish to bring before you to-night is my annual report on the work done during 'last year in the laboratory which is under my charge. With regard to the particular circumstances under, and the purposes for which the sample were taken, and also the methods employed for their analysis, I must refer you to former communications of a similar nature. (THE ANALYST, vii., p. 53 ; viii., p. 33 ; ix., p. 56 ; x., p. 6'7 ; xi., 66, and xii., p. 39.) The total number of analyses made during the year 1887 is 20,483, of which 1 S,6 11 are analyses of milk. 1,066 1 9 cream. 661 7, skim milk. 38 9 ? buttermilk. 13 7 9 butter and butter-€at. 9 , cheese. 3 0 ? medicinal milk preparations.42 ,) snndry articles. 3 29 water. 9 9 Besides these analyses, about 50,000 specific gravity determinations have been made during the year. ' Of the milk samples analysed 12,663 were taken from the railway churns on their arrival in the dairy, while 2,948 were taken by the inspectors employed by the business from the men, whilst the latter were serving tBe customers. The monthly averages of all these analyses may be found in the following table. * Since the above note was read, I have tried the sulphuric acid treatment on a sample of hops which gave a sensibly bitter extract to chloroform when the lead was removed by sulphuretted hydrogen, and found all trace of bitter had disappeared, even when the concentrated solution was agitated with chloroform, and the evaporated chloroform solution tasted.-A.H. A.THE ANALYST. 47 AVERAGE COMPOSITION OF MILK. I 1887. Speciiic Gravity. January . . . . . . February . . . . . . March . . . . . . . . April . . . . . . . . . . May . . . . . . . . . . June .......... J'uly .......... August ........ September. . . . . . October., . . . . . . November. . . . . . December , . . , . . Fat. Yearly Average. . 1,0322 Samples Taken 3.82 On Arrival. I 1.0324 1.0324 1.0325 14323 1.0324 1.0323 1.0318 1.0315 1.0318 1 *0324 1.0325 1.0325 Solids not Fat. Total Solids. 9-14 9.15 9.17 0.09 9.13 9.1 1 8.98 8.95 9-07 9.20 9.23 9.31 12.9 1 12.90 12-86 12.71 12-88 12.83 12.64 12.82 13-19 13-21 13-24 13.3 0 13-94 On Deliverj-. Total Solids. 13.93 12-77 13.77 12.64 13.87 12.78 12-60 12.85 13.15 13.15 13.13 13.04 12.8'3 From these figures it will be seen that tliere is a very slight difference between the two series of samples, generally in favour of the samples taken on arrival, a difference which on a former occasion I have assigned to the difficulty of thoroughly mixing the large quantities of milk contained in the railway churns, and to the tendency of cream to rise in the delivery churns.The very minuteness of the differences mentioned suffi- ciently proves that no serious errors can have been committed in taking the samples. The objection may be raised, that the close agreement of average figures does not exclude wide differences in individual cases. It is true that such differences may occur, and in point of fact do occur, but fortunately they are of very rare occurrence.During last year I have made very extensive series of experiments with a view to investigate into the behaviour of the milk while being delivered to the customers. The particular question to be answered was,-are changes of any importance taking place in the distribution of the fat during the time the milk remains in the delivery churns 1 The investigation was carried out in January, March and August, and comprises 171 experiments. In each case a sample was taken from the well-mixed milk contained in the delivery churn before the latter left the yard, and a second sample of the small quantity of milk left in the churn on return of the man from his round. I do not intend harassing you with the results of 342 analyses, but shall confine myself to stating that in 2 cases out of 171, or 1.2 per cent,, the samplss of milk returned from ths rounds contained a plus of more than *3 per cent. of fat, viz., 932 and 034, in 8 cases, or 4.7 per cent., tc plus of from 4 to -3 per cent., and in 20 cases, or 1107 per cent,, 8 plus48 THE ANALYEXI. ...... ... ... ... ... ... I ... * * * I February March April ... ... . . . . I of from *1 to -2 per cent. of fat, Here then we cannot speak of serious changes in the distribution of the fat, and it is very fortunate that this appears to be the rule under the conditions under which the business with which I am connected, and similar businesses are working. That exceptions do occur, I have brought under your notice on several occasions, when laying before you cases observed by myself of abnormally quick rising of cream in milk whilst being delivered to the customers.(TIIE ANALYST, viii., p. 2 ; ix., p. 57.) Samples of cream as supplied to customers were regularly taken before the cream was sent out, as well as from the men on the rounds. The average amounts of fat found in the two series of samples are contained in the following table. AVERAGE AJrorrsT OF FAT IN CREAM. 43.5 43.4 43.7 43.2 43.3 I 43.3 ~ -~ ~ Samples Taken ;I I , Yea riy Avt rage ... ... ... 43.2 I 1887. 43.9 1 Before sent out. 1 On delivery. !I __ -___ ..... .. . . . . . . .-- - - ..... The composition of 51 samples of clotted cream was as follow :- Limits. Average. Water . . . . 31.16 to 44.1G . . 36.94 per cent. Fat.. . . . . 46.92 ,, 62-00 , . 55.51 ,, Solids-not-fat . . 5.26 ,, 11.41 . . 7 5 5 Y, Ash .. . . *46 ,, -85 . . -58 9 , In skim milk samples the fat was usually found to amount to from e l 5 to *40 per Ten samples of butter were analysed with the following results :- confa, and in very exceptional cases only above -40 per cent. was present. Limits. Average. Fat .. .. . . 89-57 to 88.34 . . 85-14 per cent. Water .. . . 9.54 ,, 14.39 . . 12.93 ,, Ash, including NaCl 009 ,, 3.15 . . 1.03 ,, Insoluble fatty acids S7-40 ,, 88.86 , , 88.08 ,, Proteids, etc. . . -44 ,, 1.26 . . -90 Y,THE ANALYST. 49 A sample of whey butter contained :-- Fat 86.35 per cent.; Water 10.58 per cent. ; I Ash, 2.37 per cent. 1 Proteids, etc., -70 per cent. ; In two samples of butter-fat, which had been kept for a year exposed to the action of air and light, and had attained a waxy appearance, the insoluble fatty acids were reduced in the one case from 88-33 to 85.97, and in the other from 87.61 to 84.41 per cent. There were also some examinations of other fats made with the following results :- Beef Tallow, melting point 4 9 O C.; insol. fatty acids, 95.23 per cent. Lard 9 , 41@ c., 9 9 9 , 95.04 ,, Olive Oil . . . . . . . . 1, 9 , 95.18 ,, A sample of Cheddar cheese which was sent to me analysed as follows :- Water, 38.31 per cent. ; Fat, 29.13 per cent. ; Casein, etc., 39.47 per cent. ; Ash, 3.09 per cent. ; 01, -37 per cent. So far the cheese was of quite normal composition, but when I came to analyse a larger quantity of fat extracted from the cheese I found the insoluble fatty acids to amount to 92-76 per cent., and the quantity of deci-normal potash required to neutralise the distillate from 3.5 grms. to be *!I C.C. What I had under my hands was an artificial fat cheese, which, I must admit, was very well made. Mutton Tallow ,, 4 9 O c., 9 , 1 , 94.82 ,,

ISSN:0003-2654    

DOI:10.1039/AN8881300046

出版商:RSC    

年代:1888

数据来源: RSC

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THE ANALYST. 49 ON THE RELATION BETWEEN SPECIFIC GRAVITY, FAT, AND SOLIDS I N MILK. BY DR. P. VIETH, F.C.S., F.I.C. (Read at the Meetiq, Februayy, 1888). THE relation between specific gravity, fat, and solids in milk has been before the Society :t very short time ago. As the subject is however, one of great interest and the very greatest importance, I venture to make a few observations on it to-night. At the December meeting Mr. Hehner brought before us an extensive series of ex- periments sbowing the percentages of fat extracted from milk dried on paper coils, and calculated from his new formula. The agreement is very close indeed, and the calculation leaves nothing to be desired. I n the discussion on Mr. Hehner’s paper I took occasion to remark that the experiments a t the same time bore out a fact to which I have re- peatedly drawn attention, viz., that the differences between the percentages of fat extracted if the coil process is employed, or calculated from Hehner’s new formula, and fat extracted if the plaster process is used, or calculated from Fleischmann’s formula, are smallest with skim milks, and increase with the increasing percentage of fat ; or, in other words, that the differences are small where great difficulties for the complete ex- traction of fat exist, and comparatively large where no such difficulties are present.Thus, in Mr. Hehner’s series of analyses the following differences occur :- *1 to 1.0 per cent. f a t ; average difference, -*02 per cent. 5 samples with 3 9 , 9 , 2.1 Y, 3 4 1, 7, 9 , 99 -*IS ,, 14 9 , 7, 3.1 9 , 4.0 3 9 9 , 9 , 9 9 - 9 3 ,, 10 9 9 ,, 4.1 9 , 5.0 7, ,, 9 9 9 , -030 ,, 7 9 , 3 9 5.1 7, 6.0 9 , 9 , ? 9 9 9 -as31 ,, 1 9 , $ 9 6.20 7, 9 ? 9 9 , -94 $7 1 7 9 9 , 11.63 1 , 9 7 1, ?, -0.41 ,, 1 9 , ? ? 24-06 ,, 7 9 9 , 99 -*65 ,,50 THE ANALYST.If you take the trouble to look into THE ANALYST, xii., p. 63, you will see that I have found similar results two years ago. No explanation has as yet been offered for this very curious fact, which is the reason that I have not adopted the coil process, although I admit that it is rather more convenient and simple than the plaster process, especially if worked in the way suggested by Mr. Hehner. Results obtained by employing the plaster process, which I an1 still in the habit of using, must be compared with figures calculated from Fleischmann's formula.I thought it interesting t o compile a greater number of such figures than are usually obtainable. Looking through my laboratory journals since 1881, I extracted 694 analyses, which allow to compare figures for fat extracted and fat calculated. Among these analyses there are a great number which have been mads with the utmost care and in duplicate, while in other cases there was neither occasion nor opportunity for making the analyses in duplicate. I give here the results of 628 analyses in a tabulated form. ~~ ~~ Specific Gravity. Samples. - Difference. Limits. I Average. 141 16 11 11 21 43 124 95 38 14 16 0.1 to 0.5 0.6 ,, 1.0 1.1 ,, 1.5 1.6 7 ) 2.0 2.1 ,, 2.5 2.6 ,) 3.0 3.6 ,, 4-0 5.1 ,, 10.0 3.1 7, 3-5 4.1 ,, 4.5 4.6 ,, 5.0 MIXED MILKS.8.8 to 10-0 j 1.0345 to 1.0385 5.3 ,) 9.8 1.0200 ,, 1.0370 6.7 ,, 9.6 ~ 1.0245 ,) 1.0370 6-S f 7 9-7 , 1.0210 :, 1.0360 5.1 ,, 9.4 1 1.0180 ,, 1.0345 6.7 ,, 9.7 1 1.0230 ,, 1.0350 7.5 ,7 10.0 l * O P G c > ,, 1.0360 8.0 ,, 9.7 1*0280 ,, 1.0350 8.1 !, 10.1 1 1.0300 ,) 1.0350 8.9 ,? 9.6 I 1.0305 ,, 1.0350 8.6 ,, 9.8 I 1.0255 ,, 1.0335 + a04 + -03 - -02 + *02 + 4 3 + *03 + -01 -P *01 + -05 + -01 - -02 MILK OF INDIVIDUAL Cows. 33 I 2.0 ,, 7 . 3 ' 6.4 ,, 10.8 1 1.0205 ,, 1.0350 1 - - - 2 9 , +'3 i +*O3 BUTTERMILK. 65 I -4 ,, 3.1 I '7.3 ,, 9.9 I 1.0360 ,, 1.0355 j - - 2 7 , +'3 I +'02 There are, first of all, 530 samples of milk of very widely varying degrees of rich- ness: poor skim milks, half-skimmed milks, milks with an average amount of fat, rich milks, and mixtures of milk and cream.Included are a number of samples t o which water had been added. The differences between fat found and fat calculated range from -*2 to + * 2 and average +-02. All these samples refer to mixed yields of several, in most instances of a good many, cows, and the question arises, whether in tho case of milks of individual cows the calcu- lation is applicable with the same good result. This question is answered in the affir- mative by the thirty-three analyses which follow next in tho table, showing the same rango of differences as the previous samples, viz., from -- 4 to + -2 and an average difference of +*05.THE ANALYST. 51 We now come to sixty-five analyses of buttermilk, which were either perfectly sweet or at least of a degree of acidity, and on the whole in a condition allowing the specific gravity to be determined with sufficient accuracy.Here again we have differences rang- ing from - *2 to +-2 and averaging + -02. The possibility of applying formu1;ic of the kind in question is, of course, basedupon the assumption that the specific gravity of the milk fat on the one hand and the non- fatty solids on the other are practically constant figures. We know that the specific gravity of pure butter fat is -93, and Fleischmann, when working out his formula, has found that the specific gravity of non-fatty solids is 1.6 ; but what the specific gravities of the several solid component parts are, as long as they, in conjunction with water, constitute milk, we know not.There’ can, however, be no doubt that proteids, milk-sugar, and the mineral salts, forming the non-fatty solids, have different specific gravities, and I believe we may reasonably assume that the specific gravities decline in the order, ash, sugar, proteids. If the specific gravity of the non-fatty solids is always a constant, or nearly constant, quantity, we must admit that the relative proportion in which the three constituents are present is also constant, or nearly so. Roughly speaking one half of the non-fatty solids is sugar, the sixth part of the other half ash, and the remainder proteids; or, to put it in other words, ash, proteids, and sugar, are present in the proportion of 1 : 5 : 6. As long as this is the case, formuk like Fleischmann’s and Hehner’s can be applied with satisfactory results. As soon, however, as this relative proportion is seriously disturbed, the application of the formu1:e with anything like success becomes impossible.The following figures prove that beyond doubt. I n artificial human milk, as manufactured under my superin- tendence, the relative proportion of ash, proteids, and sugar is 1 : 5 : 10; in seventeen analyses the differences, when the formula was applied, ranged from --.4 to 0.0, and averaged - -21. I n special milk food, another medicinal preparation for infants, the relative proportion is 1 : 3 : 10 ; and in eleven analyses differences from ---7 to -9 average -042, were found. In mare’s milk, which I bad the opportunity of analysing Eome years ago, the proportion in question is 1 : G : 23 ; in thirty-one analyses the differences varied from -06 to 0.0, and averaged - 9 5 . Lastly, I applied the formula to analyses of condensed milks, dilufed or dissolved in proportion as prescribed, when I got the following results :- 1 sample milk powder , . .. . . difference - *1 per cent. 2 samples milk, condensed without sugar ,, 0.0, --1 Y, 1 sample ,, ,, with sugar . . ?, - @4 7, 3 samples condensed mare’s milk . . 7 9 -93, -21, -05 I n conclusion, I venture to express my belief that the figures contained in what precedes clearly prove how very useful and widely applicable Fleischmann’s as well as Hehner’s formula are, for both formula will give equally satisfactory results if applied in their proper sphere. At the same time my figures indicate where the application of the formule has to atop, (Conclusion of the Society’g Proceedings.)

ISSN:0003-2654    

DOI:10.1039/AN8881300049

出版商:RSC    

年代:1888

数据来源: RSC

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52 THE ANALYST. NOTE ON A TEST FOR (~HYDR~NAPHTHOL.~~ By ALFRED L. BEEBE, ASSISTANT CHEMIST, NEW YORK CITY HEALTH DEPARTXENT. HYDRONAPHTHOL,” so-called, has lately come into considerable prominence as an effective antiseptic for use in the preservation of various food products. A reliable method for its detection is therefore desirable. So far as the writer is aware, no distinctive test has as yet been given for the detection of this substance, when present in minute quantities, and the results of some experiments in this direction may therefore prove of interest. It is sparingly soluble in cold, much more readily in hot water, and is easily extracted from its water solution by shaking with ether. The etherial extract, evaporated to dryness and taken up with hot water, or the water solution direct, in absence of interfering substances, made slightly alkaline with ammonia, cooled, and slightly acidified with dilute nitric acid, gives, on addition of a drop of fuming nitric acid or a nitrite, a beautiful rose color, analagous to that developed in the test for nitrites in water. ‘‘ Hydronaphthol,” as is well known, is really a trade name for p naphthol. * Died, Centr,, 1887, 694-G9!3,THE ANALYEIT.53 In making the test a r e should be taken that the ammonia and nitric acid are respectively added in slight excess only, and that the nitric acid used is so dilute as to cause no heating of the solution by its combination with the excess of ammonia present. If these precautions are not observed, a dirty salmon colour is apt to be developed by the addition of the fuming nitric acid, and the distinctive character of the test thereby destroyed. The reaction is one of extreme delicacy, one part in ten thousand of “hydro- naphthol ” being readily detected. Experiments are now being made by the writer, to determine the limit of delicacy of the test, and also t o arrive at a practical method for separating hydronaphthol ” from food products to which it may have been added, in a condition suitable for the application of the test outlined above. The results of these experiments, if successful, will be published in due course.

ISSN:0003-2654    

DOI:10.1039/AN888130052b

出版商:RSC    

年代:1888

数据来源: RSC

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THE ANALYEIT. 53 DO CEREALS CONTAIN SUGAR." BY PROF. DR. ALEX. V. ASB~TH. IN my paper on the determination of starch (see ANALYST, July, 1887) I came to the conclusion that cereals do not contain any sugar. Baryta water does not preci- pitate sugar in presence of alcohol, and still my full analyses of various cereals came veryclose up to 100 per cent., leaving, therefore, no room for any sugar. As, however, Windish pretends that, by following the details of my process, the sugar cannot be estimated, and many chemists of repute have found sugar, I once more investigated the matter so as to prove myself in the right. TABLE, STIOWING THE AMOUNT OF SUGAR FOUND IN NON-GERMINATED BARLEY AND WHEAT BY SEVERAL AUTHORITIES ( KUHNEMANN). ('I 0 " means not found ; '' -" means not tried for.) BARLEY.W II EA T. Sugar. Dextrin. Sugar. Dextrin. Per cent. Per cent. Pel. cent. l'er cent. __ - - Thomson (1817) . . * . 4 Groust (181s) . . . . 5 4 Peligot . . . . . . 0 Boussingault . . . . _- 7.2 Polson . . . . . . -- 4.8 -- 5 3 - - - -- - - Saussure . . . . . . - - 2.4 3 4 } (Ism) . . 0 Mulder Oudemans - -- - Mitscherlich . . .. 0 Her ms taed t . . . . 4.7 4.5 Einhof (1838) . . . . 5.3 4.6 W. Stein (1860) . . * . 0 6.5 Pillitz (1872) . . . . 2-71 1.96 1.60 1.76 According to Oudemans, analysts have now and then found sugar, because they extracted the flour with water, which caused the dextrin, and probably some of the starch, to invert. If flour is extracted with absolute alcohol, and the solution evaporated to drynessaresidue is obtained which, after inversion with strong acetic acid, reduces the copper solution, and yields about -2 per cent.of sugar ; but even these small traces are not really pregent as such in the original flour. Most likely they arederived from a little dextrin, * Uherp, Zeit., 2 and 4, 1888, -- c - - - -54 THE ANALYST. as this substance is not quite insoluble in alcohol, and flour probably contains small quan- tities of copper-reducing substances which need not necessarily be sugar. Krocker extracts the flour with limewater and filters. The filtrate is freed from albuminoids and excess of lime by a current of carbonic acid. Sugar could not be detected in the filtrate. Schlosing estimates sugar as follows :-lo to 19 grammes of finely ground sub- stance are repeatedly rubbed in a mortar with small quantities of water, and finally ex- hausted in a displacement apparatus. The filtrate is divided into three equal parts.Sugar is estimated by Fehling’s solution in om half of one of these parts. The other portion is used for determining the dextrin. He evaporates the watery solution and then extracts with rectified spirits of wine. The alcohol is distillsd off and the residue dissolved in a definite volume of water. If much colouring matter is present some animal charcopl must be used. The filtrate is divided into two equal parts and the glucose estimated, best by the well-known mercury solution. The other part is heated with a few drops of sulphuric acid for two hours in the water-bath, and then treated like the first. Any increase in sugar is calculated to cane-sugar. J.Bell gives the following method :-I0 grammes of finely powdered material are extracted with alcohol of 70 per cent. The alcoholic solution is evaporated, and the residue inverted with 5 C.C. of normal sulphuric acid. The sugar is then estimated by one of the well-known processes. To practically ascertain whether these processes give reliable results, and to prove my case, I have made the following experiments :-- 1. 10 grms. of maize-flour were gelatinised with 50 C.C. of water, and, whilst still warm, mixed with 200 C.C. of 80 per cent. alcohol. After cooling, the liquid was filtered and evaporated to dryness. I took up the residue with a little water and tested a little of it with Fehling. Notwithstanding the fluid gave a copious precipitate with baryta water and proof spirit, I could scarcely get any reduction of the copper solution. 2 .About 16 grammes of maize-flour were extracted in the cold with 200 C.C. of 80 per cent. alcohol; the latter evaporated and the residue dissolved in water. This solution (which but sparingly reduced Fehling) was mixed with lime water and boiled. The excess of lime and other impurities were removed by carbonic acid and the filtrate evaporated to dryness. The residue was again treated with rectified spirits of wine, when an insoluble yellow powder remained undissolved. The filtrate had a brownish colour, and left, after evaporation, a brownish sticky mass, readily soluble in water. The substance is, no doubt, erythrodextrin. With iodine it gives a red colour, and it does not reduce Fehling until it has been boiled with hydrochloric acid, 3.Experiments with wheat and peas gave similar results. 4. 20 grms. of maize were extracted according to Schliisiag’s process. The solution I now come to the following conclusions :-The cereak contain no sugar, neither Analysts who have apparently found it have made use of wrong SchlGsiag’s process is wrong, because the erythrodextrin, and most likely some of Koenig modifies this process. This was impure dextrin. This solution is precipitated by baryta water in presence of alcohol. strongly reduced the alkaline copper solution. glucose nor saccharose. processes.THE ANALYST. 55 the starch, yield a little glucose by mere treatment with water. Koenig’s modification is also wrong, as my experiments plainly prove cereals contain a gummy-like substance, soluble in alcohol, which yields glucose on boiling with acids. The process of J. Bell and Rasenach also gives inaccurate results, as dextrin is perceptibly soluble in rectified spirits of wine, and the subsequent boiling with acid will make this into glucose. Then there is also the dextrin-like substance which I have found in all cereals, and which also yields glucose on boiling with acids. As dextrin and erythrodextrin slightly reduce copper solution on prolonged boiling, it is not to be wondered at I sometimes got, in my analpes, slight reductions which ought not to have taken place.

ISSN:0003-2654    

DOI:10.1039/AN8881300053

出版商:RSC    

年代:1888

数据来源: RSC

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55 -- THE ANALYST. ___- THE ACTION OF ALCOHOL ON BUTTER FAT. IN order to test artificial butter for added butyrates it has been recommended that the suspected sample be treated with alcohol, which will dissolve any artificial tributyrate. If the undissolved fat then be tested by Reichert's method, we shall find the per cent. of volatile fat acids much less than in the original fat, in case any artificially prepared butyrates have been used. If this plan of examining suspected butters is ever to be called into practical use, it is, in my opinion, highly desirable, if not absolutely necessary, that we have some definite knowledge of the action of alcohol upon genuine butter fat, under certain fixed conditions, such as could easily be adopted when examining suspected samples. The following experiments were made for the purpose of determining what changes, if any, were produced in butter by treating it with ethyl alcohol.The alcohol used gave a specific gravity corresponding to 90 per cent. C2H60. The amount used was 10 C.C. alcohol to each gramme of butter fat. B Y PROF. C. B. COCHRAN, WEST CHESTER, PA., U.S.A. C.C. EKHO required for distillate of 50 C.C. from 24 grms. (REICHERT'S METHOD.) J- --- h Bample. "$:f:$.Td Temperature. gutter fat. Dissolved fat. Undissolved ;at. 1. 0.10133 788F. 13 C.C. 24 C.C. 2. 0-1086 '788F. 25ii- C.C. 9$ C.C. .I. 0.1 30 19g C.C. 9& C.C. > 11 C.C. 768F* f 103 C.C. , Y 4. 0 *I 20 758F. 15&x. 27& C.C. 13& C.C. f 12& C.C. 1"A '1 l a i % C.C. 5. 0-126 d--- C.C. 2Bi4* C.C. \ I W Sample No. 4 giving in one case only 10% c.c., and 11 C.C.$ KHO in another, to neutralise the distillate from 24 grms. of fat was more than 10 months old. I n a third test of this same butter known to be genuine lo$ C.C. KHO were required. This butter was at the time in a state of' good preservation, and was perfectly palatable. Hehner and Angell, in their work on butter analysis, found that the insoluble fat acids of butter increased somewhat with age. This being the case we might expect some decrease in the per cent. of soluble fatty acids, and this result, therefore, seems to be in accord with the report of Hehner and Angell. Three other samples of butter tested in a similar way, but no attention paid to the condition of temperature, gave results as follows : .-56 THE ANALYST.PER CENT, OF VOLATILE FAT ACIDS IN 1. 6& per cent. 523G per cent. lo+& per cent. Undissolved fat. Dissolved fat. Sample. Butter fat. 8. 5-93 1oa 7 7 3& 7 7 14$& 7 ) 3. lb 9 7 2245 7 ) 1 0 0 1, 5 2 ‘t 11-82 The per-cent. of volatile fat acids in the above table was determined in each case by Experiments made with wood alcohol show similar results. I here give results of the process of repeated distillations and calculated as butyric acid. two such experiments, the proportion of alcohol to fat being 10 C.C. to 1 grm. C.C. ZKHO required to neutralise 50 C.C. distillate from 28 grms. h Fat dissolved Temp. ;utter fat. Undissolved fat. Dissolved fat: by 10 C.C. 1. 225 75OF. 15& 9i‘ 23; 2. 218 75OF. 10% 1-9 15.0 e 22& The second sample of butter was the same as mentioned above, and was ten months old.From the above work it is very evident that the portion of fat dissolved by methyl or ethyl alcohol is rich in volatile fat acids. We conclude, therefore, that while the glycerides of the volatile fat acids are present in butter in such a condition as not t o be readily dissolved by alcohol, yet a part of them yields to the solvent action of this reagent more readily than some of the other fats of the butter. This excess of volatile fat acids in the fat dissolved by alcohol is not due simply to the solvent action of alcohol upon any free fat acid which may be present, as my method of experimenting eliminated this possibility. ’ If one suspects a butter of being adulterated with an artificial butyrate, and attempts to dissolve such an adulterant by the use of alcohol, it seems necessary to use an alcohol of known strength and to have a known quantitative relation between the alcohol and butter fat employed.If the fat undissolved by alcohol be then examined he must expect t o find the quantity of volatile fat acids diminished somewhat even in genuine butter. Using the method I have adopted I should judge that the undissolved fat of a a genuine butter ought to require 9 C.C. of KHO to neutralise the usual distillate from 2$ grammes. If less than nine are required there would be reason to suspect adulteration. I am inclined to think that more information would be gained by applying Reichert’s method to the fat undissolved by alcohol than by applying it to the original fat if we adopt 9 C.C.Fo KHO as the amount of alkali required to neutralise the distillate from 2$ grammes of fat strictly following Reichert’s method. This would in most cases show at once the adulteration even in case of an added butyrate; when the same method applied to the suspected butter would not detect this. Hiibl’s iodine test also shows that the composition of fat dissolved by alcohol differs from the portion undissolved. I n the following tests the fat was dissolved in wood alcohol of specific gravity -817 at 60° F. The proportion of alcohol used was 10 C.C. to one gramme of fat.THE ANALYSI'. 57 - Sample, Fat dissolved Temp, Iodine No. of Iodine No. of Iodine No. of by 10 C.C. fat. dissolved fat Undissolved fat. 38&- 45-8- 3 7 i 1.-225 grm. ' i 5 O F. 07 33-:% 2. 34& 3. -21s grm. 1 U 1 U 1 0 45 3 - 43-L Below are two determinations of the iodine numbers when ethyl alcohol 90 per cent. C,H,O was used to dissolve the fat. sample Fat dissolved Temp. Iodine No. of Iodine No. of Iodine No. of by 10 C.C. Eat. dissolved fat. Undissolved fat. 1. -126 grm, 4 0-4-6 106 37& 42&- 2. 01197 ,, 82Q F. 41& 3 6$3c 42& The fat dissolved by alcohol has a very low melting point, remaining liquid at all ordinary temperatures, while the undissolved portion has a melting point higher than pure butter fat. An attempt was made to determine the character of the fat acid condensed in con- denser during distillation with the following results :-- The fat acid collected in condenser was dissolved in neutral alcohol, and titrated with Weight of Ba salt thus formed = 0.1325 grin. Weight of BaSO, produced from this salt = 0,063 grm. Weight of BaSO, which would correspond to 0,1325 grm. of .Ba(C,,H,,O,),= 080644. The melting point of the fat acid collected in condenser was twice determined, and in one case was found to be SOo F., and in the second case S6O P. The last melting point corresponds to that of capric acid. From the above results I judge that the fat acid collected in condenser is composed mostly of capric acid. Before concluding this article I wish to say that in my opinion the standard of 12; C.C. $ KHO as frequently adopted for Reichert's method will need some modifi- cation. While fresh butter will give results as high as this standard, or exceeding it, I believe that in case of butters that have been kept for some time we may obtain results short of this. At least this has been my experience with butter made at my home in the fall, and kept over winter, although the butter was still very palat.able. In one case the undissolved portion had a melting point of 106O F. baric hydrate ; this formed a heavy white precipitate.

ISSN:0003-2654    

DOI:10.1039/AN8881300055

出版商:RSC    

年代:1888

数据来源: RSC

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THE ANALYSI’. 57 AN IMPROVED FORM OF GAS APPARATUS. BY J. T. WILLARD.* THE description of an improved form of Elliott’s apparatus for gas analysis, by J. B, Mackintosh, recalls one devised by the writer. It was constructed for use in the chemical laboratory of the State Agricultural College of Kansas, and was used in an examination of the natural gases of that State by Prof. G. H. Failyer. As it embodies some advantages not combined in any other apparatus that has come under the notice of the writer, a description of it may not be amiss. It is essentially a combination of Elliott’s apparatus and Frankland’s apparatus for the analysisof gases incidental to water analysis,? with important modifications and additions. The accompanying cut will make its con- struction clear. * American Chemical Journal.t Journal Chem. Society 21, 109.58 THE ANALYST. A is a pressure tube graduated in millimetres. .- B is the measuring tube holding about 120 c.c., 100 C.C. of which is graduated to tenths, beginning with the stopcock P. Its upper part is narrow, thus admitting accurat,e measurement of small amounts of gas as well as large. It is enclosed in a water jacket which must be provided with some means of securing a uniform temperature throughout. C is the explosion tube and is ungraduated. D is the absorption tube surmounted by a funnel for the introduction of reagents. E i s a laboratory vessel of the ordinary kind, which may be attached instead of I) if desired. It is obvious that any form of absorption pipette may be attached at f.B, C and D are connected by the stopcock F, a four-way cock shown in section above. By means of this cock, the others being suitably arranged, either tube may be put in connection with either of the others or with the external air, without disturbing the other tube or tubes. Reservoirs not shown in the cut are attached to the tubes by means of rubber tubing at a, b and c. The ends of the tubes are closed by rubber stoppers, and the several parts are connected by heavy rubber connectors at d, e , f , and 9. The ends of the capillary tubes are ground squarely a t these joints so that they come together perfectly. The apparatus is firmly attached to a suitable support, such as any one with a little ingenuity may devise, It is essential that A and B be so supported that their relative position shall remain unaltered.The apparatus was designed for use with mercury, but water may be used. With water the pressure tube would be unnecessary, G is an ordinary three-way cock.THE ANALYST. 59 Concerning the mode of operating the apparatus but Aittle need be said. It irS most convenient to use Frankland’s method of measuring, in which the gas operated upon is always brought to the same volume, or to an aliquot part of the original volume, by adjusting the pressure of the mercury in A . Points on the pressure tube correspond- ing to a number of convenient volumes in the measuring tube must be previously determined with care. The tensions exerted by varying amounts of gas brought to the same volume will be proportional to the amounts of gas present. If the gas is brought to an aliquot part of the original volume, the tension found may be reduced to that corresponding to the original volume by a very simple calculation.The explosion of the gases is performed under reduced pressure according to the principles developed by Thomas. This method of explosion is very advantageous and may be used with this apparatus, even if water is used in the tubes B and D, by filling C with mercury. On lowering the reservoir connected with C any desired degree of rarefaction may be produced. It is convenient to have a rough scale back of C and extending below, for use in measuring the pressure under which the gas is confined during explosion. The fourth way in the stopcock P is essential for the discharge of the reagents employed in D; it is also used for the introduction of the gases.I f it is desired to preserve a portion of the gas in D while another portion is being measured and exploded in B and C, it is necessary to close this external opening of F. This may be done simply and perfectly by filling the way with water or mercury from one of the tubes, and then slipping a short piece of rubber tubing filled with water over the end of - the stopcock and closing it with a clamp. I think no other details of manipulation need be entered into, as they are similar to those already described for other apparatus, or can be readily worked out by the operator. The appamtus may be used for certain of the purposes to which the nitrometer has been put, such as the valuation of bleaching powder by hydrogen peroxide and vice vema. The apparatus described was made in most excellent manner by Mr. Emil Greiner, New Yo rk. MONTHLY RECORD OF ANALYTICAL RESEARCHES INTO DRUGS. REACTION OF COTTOWSEED OIL. M. LABICHE. L’ Union Ph.-Treated with sub- acetate of lead and caustic alkali, cotton-seed oil gives, almost immediately, an orange- red reaction. This is peculiar to this oil, for almond, castor, olive, poppy, rape, andcod- liver oils give a milky mixture, which is also the case with butter when thus treated. The author mixes equal parts of the oil and a saturated solution of neutral acetate of lead, and adds ammonia, stirring briskly. The acetate decomposes, and the nascent oxide reacts upon the oil. After standing, the surface turns orange-red and the lower portion becomes grumous. I f 20 per cent. of cotton-seed oil be present, the colouration appears at once ; lesser quantities show on the surface after the mixture has remained standing for a time. Then the red colour appears. W, H. D.

ISSN:0003-2654    

DOI:10.1039/AN8881300057

出版商:RSC    

年代:1888

数据来源: RSC

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60 THE ANALYST. ERRATUM.-h Messrs. Hehner and Richmond’s paper on ‘‘ The relation of specific gravity, fat and total solids, p. 27, aixth line from top, rezd ‘‘ Fleischmann’s plaster extraction formula” instead of r‘ Morgan’s formula. ”

ISSN:0003-2654    

DOI:10.1039/AN888130060b

出版商:RSC    

年代:1888

数据来源: RSC