摘要:

Butter Analysis in Scotland . . . . 105 ,Sulphuric and Hydrochloric Acids in Vinegar, 1&c., by Otto Hehner . . . . 105 IThe Colouration of Wines . . .The Latest Chemical Discovery . . . 112Review-Analyst’s Annual Note Book . . 113log 1 Correspondence-Butter Fat, Dr. Dupr6,F.B.S. . . . . . . 114Correspondence-Milk of Sulphur, A. Bird,F.C.S. . . . . , . . 115Volumetric 1)etermination of Phenol 116Offences under the ‘ I Salc of Food and.Drugs Act” . . . . . . 117 ___J, FALCONER KING.A. WYNTEH, BLYTH, M.R.C.S.OTTO HEHNER.C. A. CANEBON, M.D.E. W. T. JONES, F.C.S. c. R. PIESSE, F.C.8.F. J. LLOYD, F.C.S

ISSN:0003-2654    

DOI:10.1039/AN87601FP001

出版商:RSC    

年代:1876

数据来源: RSC

摘要:

THE A N A L Y S T . BUTTER ANALYSIS I N SCOTLAND. FROM the Report of a Scotch prosecution for selling adulterated butter, which we print in another column, it would appear that butter analysis is but little understood at the Andersonian University. Some years ago the then Professor of Chemistry came to grief on an analysis of butter, and now his successor, Dr. Dittmar has failed even more lamen- tably, in conjunction with Dr.Stevenson Macadam, of Edinburgh. As we believe neither of these gentlemen holds the position of a Public Analyst, we shall be spared the usual outcry about the imbecility or incompetence of Public Analysts. Drs. Macadam and Dittmar are reported to have stated that they had examined the sample in question both by Bell’s and Muter’s processes, and also by the ‘‘ old system,” and finding the butter good according to the latter, which they thought was the most reliable one, they pronounced it pure.We have no doubt that all adulterators will hail with delight this return to ‘( old systems,” but, that two gentlemen with some knowledge of Chemistry, should have been found deliberately t o prefer old and utterly worthless methods is more than we should have thought possible.Everyone with the slightest knowledge of the subject must have known that, up to the last few years, there was no system according t o which butter fat could safely be distinguished frcm other animal fats, and, as a matter of fact, no chemist, who had any regard for his reputation, ventured to affirm the contrary. During thelast two years, however, thanks mainly to the initiative taken by Messrs.Hehner and Angell, the subject of butter has been much worked at, and its analysis is now as well understood and as certain, as any other process in the whole range of food analysis. We do not blame Drs. Macadam and Dittmar for being ignorant of this, as the subject probably lies outside their usual pursuits, but we do blame them for being ignorant of their ignorance, and for venturing to gire evidence in a court of law on a subject with which they were so imperfectly acquainted.Taking the evidence of both sides there cannot be the slightest doubt that the sample in question consisted mainly of fat other than butter. We trust that this case may serve as a warning to the Analysts of Scotland, and that when next we have to report a case of butter adulteration we may find that an intelligent knowledge of the processes for the analysis of butter is possessed by the Chemists engaged, whether they are employed for the prosecution or the defence.ON THE DETECTION AND QUANTITATIVE DETERMINATION OF FREE SULPHURIC AND HYDROCHLORIC ACIDS I N VINEGAR, LIME AND LEMON JUICES, AND SIMILAR LIQUIDS.By OTTO HEHNEB. ALTHOUGB a large number of methods for the detection and determination of free mineral acids in vinegar have been proposed, yet there is none, as far as I am aware, which could be considered to fulfil all the requirements expected from such a method. These require- ments are, first, that a simple quantitative test should at once answer the question, whether a given sample of vinegar contains free mineral acids or not, so that, the result treing negative, no quantitative determination need be resorted to ; second, that the method for determining the amount of free mineral acid present should be exact within a few hundredths of a per centage; and third, that no substance or re-agent should be required which is not within reach of every chemist, and which is not to be found in the laboratory of any Public Analyst.106 THE ANALYST.The older qualitative tests as proposed by Normandy, Muspratt, and other chemists, were mostly based upon the charring action of sulphuric acid upon paper or other organic substances. Thus we read, ‘( Sulphuric acid may be detected by writing with a quill upon white paper and drying it strongly before the fire, when the paper will become charred,” but, fortunately, the author adds, (‘ if the quantity of tmlphuric acid exceed two per cent.” Another writer recommends that a drop of the suspected vinegar should be placed upon paper and dried before the fire, when a black stain will be produced, and a third, t o heat a solution of cane sugar nearly to boiling, and then to add a small quantity of the liquid containing the sulphuric acid, when the charring of the sugar will at once point out the presence of mineral acid.These absurd and worse than useless methods seem to have been in general use, as they are t o be found in most books dealing with the subject, which were written fifteen or twenty years ago. Thus i t ie directed to evaporate a measured quantity of the vinegar on the waterbath and t o extract the syrupy liquid with spirits of wine, when the sulphates will be left in the residue on account of their insolubility in alcohol, while the sulphuric acid will be found in the alcoholic solution.But I hare not unfrequently found an appreciable quantity of sulpha te to pass into solution, even where no trace of free sulphuric acid could be present.Another plan is to determine the total amount o f sulphuric acid, both free and combined, gravometrically by means of chloride of barium, and to evaporate and incinerate another portion of the vinegar, thus driving off the free sulphuric acid, and to determine in the residue left the amount of the combined sulphuric acid, the difference between the two determinations being calculated as free sulphuric acid.This method however is quite incapable of giving accurate results, as free sulphuric acid, so pertinaciously clings t o the ash, that even with the acid of carbonate of ammonium, it c:tnnot be completely got rid of without some loss by volatilisation of the sulphate of soda invariably present. I n addition, it will be seen, this method requires two tedious gravimetrical estimations, in order to find out whether free sulphuric acid is present or not, and as even in the purest vinegar, which has never been contaminated with free mineral acid, the results before and after incineration are never exactly identical, it cannot be relied upon when small quantities of d p h u r i c acid are to be determined. Mr.Thresh, in a late volume of the Pharmaceutical Journal, described a method similar in principle. He estimates the amount of chlorine before and after incineration of the vinegar, the difference being equivalent to the quantity of sulphuric acid added, but although this method is capable of giving more accurate results than the method just described, yet the same objection applies to it, namely, that two quantitative determinations are needed, to obtain a qualitative result.There have lately been published two other methods, one based upon the solubility of oxalate of lime in mineral acids, it being insoluble i n acetic acid, and the other upon the change of colour which methylaniline violet undergoes, on the addition of mineral acids, it being unaffected by vegetable acids.Both these methods, howerer, are nearly useless, the former, because the solubility of the oxalate of lime depends upon a great variety of circumstances, and the latter because the quantity of mineral acid usually present in proportion t o the acetic acid, is by far too small to allow of a direct accurate determination. Both methods may however be useful, if the quantity of mineral acid present is very large.(Muspratt.) But, besides the above methods, there are several worthy of attention.THE ANALYST. 107 As vinegar consists, except in the case of its being distilled, not merely of acetic acid and water, but always contains potash and soda salts of organic acids, as the tartrate or acetate, and chloride of soduim, it is obvious that sulphuric or hydrochloric acids, if added in small quantity, can no longer be considered to exist as such in vinegar, but that they decompose an equivalent quantity of acetate or tartrate.Whenever there is any undecomposed acetate or tartrate present in vinegar, n3 trace of any mineral acid can be present in the free state. As the organic salts of the alkalies are converted by incin- eration into the corresponding carbonates, it can safely be asserted.Fhenever the ash of a vinegar exhibits an ah'caline re action, free nzineral acid cannot be present i?z the vinegar. Nineral acid may have been added, but it then has become neutrslised by the decomposi- tion of the acetates or tartrates. We have thus the simplest possible qualitative test for free mineral acids in rinegar.The quantity of this may be ascertained with the utmost accuracy by following the same principle. If we add to a measured quantity of the suspected vinegar, a known and exactly measured volume of decinormal soda solution, somewhat more than would be necessary to neutralise the total amount of free mineral acid present, evaporate and incinerate, the alkalinity of the ash give4 the measure of the quantity of the free sulphuric or hydrochloric acid.Supposing we add 20c.c. of standard alkali to a vinegar, and find after incineration, by titration with standard acid, an alkalinity corresponding only t o ~ c . c . , then 15c.c. of the soda solution have been neutralised by the mineral acid in the vinegar. As the point of neutralisation can be far easier ascertained, litmus being used as an indicator, Fy titrating from red t o blue, than from blue t o red, and as the latter plan offers several other advantages, it is advisable to operate as follows:-A measured quantity, say 50 cc.of the vinegar to be examined, is mixed with 25 cc. of decinormal soda solution (capable of neutralizing 0,200 per cent.of SO3). The liquid is evaporated on the waterbath in a platinum basin, the residue is dried t o prevent spirting in the air, or on the sand-bath at about llO°C, and is then carefully incineratld at the lowest possible temperature. The ash need not be burned white. 25cc. of a decinormal suiphuric acid solution, corlesponding exactly t o the soda solution, are now added t o the ash, the liquid is heated to expel all carbonic acid, and is then filtered into a small beaker.The filter is washed with hot water, tincture of litmus is added to the filtrate, the acidity of which is ascertained by means of the decinormal soda solution. Ths colume of soda necessary for neutralisation directly gives the proportion of free mi?zeral acid present in the vinegar, 100 cc.of the standard solution, corresponding to 0.49 grammcs of I t may happen, when more than 0.200 per cent. of free mineral acid is present, that the 25 cc. of decinormal solution added t o the vinegar are insufficient to neutralise all free mineral acid: in that case 25 cc. of decinormal soda would be required to neutralise the filtrate. A fresh experiment, with the addition of a larger quantity of soda solution, say 35 or 40 cc.to the vinegar must then be made. An error of one cc. of decinormal soda solution, would cause with 50 cc. of vinegar an error only in the amount of free mineral acid of 0.0098 per cent., calculated as IT, SO,, but practically results of far greater accuracy can be obtained, as the folluwing experiments show. I will remark, that they are taken without selection, but were made with scrupulous care.But whenever the ash is neutral, free mineral acid is most likely present. Hz SO*.108 THE ANALYST. I. 11. I11 IV A vinegar was prepared by diluting pure acetic acid, to a strength of 5.475 per cent. and bp adding about one per cent. of cane-sugar, t o represent the organic residue present in all non-distilled vinegar.To 4 portions of this liquid as much decinormal suiphuric acid was added, as corresponded t o 02, 01, 0-05, and 0.025 per cent. respectively, and which 1 will call, I., II., III., and IT. To 50 cc. of I., I added 30 to 50 cc. of II., 111. & IT. each, 25 cc. of decinormal soda solution. The liquids were evaporated in a platinum basin, and incinerated at the lowest possible temperature, the basin not being allowed t o become heated to redness.To the carbonaceous residue in I. 30 cc. of deci. Ir, SO, were added, the liquid was boiled and filtered ; the filtrate needed 25-07 cc. of deci. soda for neutralization, equal to Oa10028 gram. 503 or 0.20056 per cent., instead of 0*2000 per cent. Error, + 0-00056 per cent. To Ash II., 25 cc.of deci. acid were added; the filtrate required 12.79 cc. of deci. soda, equal to 0.05216 gram. SO,, or 0.1022 per cent., instead of 0.100. Error, 4- 0.0022 per cent. Ash IIP., was likewise treated wiLh 25 cc,. of deci. acid, the filtrate requiring for neutralisation 6.30 cc. of acid, corresponding t o 0.0258 gram. SO,, or 0-0504 per cent. instead of 0.0500 per cent. To Ash IT., 25 cc.of deci. acid mere added ; 3.8 cc. of deci. soda were required for neutralisation, corresponding to 0.0152 gram. SO,, or 0.0304 per cent., instead of 0.0250 per cent. It will be seen that in no case is the error greater than 0.0054 per cent., and this only when the total quantity of free sulphuric acid present was as small as 0.025 per cent. As vinegar mostly contains some chloride of sodium, which would be converted by the action of free sulpburic acid into free hydrochloric acid, arid sulphate of soda, and as hydrochloric acid might be directly used as an adulterant, a similar series of experiments as that described above was undertaken, the vinegar being admixed with hydrochloric acid to the extent of 0.2, 0.1, 0.05, and 0,025 per cent..To 50 cc.of each of these adulterated vinegars, 25 cc. of decinormal soda solution was added, and the quantities determined as in the previous series. Used 24.14 cc. of deci. soda, equal to 0-08814 gram. HCl, or 0.1763 per cent. Error, 0.0004 per cent. Error, + 0 0054 per cent. The following are the results :- T instead of 0.200 per cent. Error, 4- 0.0237 per cent. Used 14.0’3 cc. of deci. soda, equal t o 0.0512 gram.H C1, or 0.1040 per cent., instead of 0.100 per cent. Error, 4- 0.0040 per cent. Required 7-9s cc. of deci. soda, equal to 0.02894 gram. H C1, or 0.05789 per cent., instead of 0.050. Used 5.63 cc. of deci. soda solutioii, corresponding to 0.0205 gram. M C1, or 0.0410 per cent., instead of 0.025. Error, + 0.0079 per cent. Error, 0.016 per cent. Thus it is shown, that although the error of estimation in the case of free hydro- chloric acid is greater than with free suiphuric acid, the results are still highly favourable and accurate, the difference between theory and experiment not exceeding 0.02 per cent.Tha experiments quoted, show that She amount of free mineral acids may be determined with far greater accuracy a,lkalirnetrically, than by any other method,THE ANALYST.109 ~~ The same method may be applied to lime and lemon juices, wherein I have repeatedly come across large quantities of sulphuric acid. With a view to establish the correctness of the conclusion, that an alkaline reaction of the ash of the vinegar is the best proof of its freedom from uncombined mineral acid, the following experiments were undertaken. They may perhaps appear somewhat superfluous, but I quote them, as again demonstrating the extreme accuracy of the method.A pure distilled vinegar was mixed with a solution of acetate of soda, and it was found, that 100 cc. mere capable of saturating 0.1065 gram. SO3, corresponding to 26.62 cc. of decinormal sulphuric pcid. To 50 cc. of this artificial vinegar, 12.5 cc. of deci-normal sulphuric acid were added, the liquid was emporated and the residue was charred at a low temperature. The ash was all but neutral, but slightly alkaline, showing the absence, as was expected of free sulphuric acid in the vinegar. The alkalinity of the ash was found t o be equivalent t o 0,0085 gram. of SO,. Theoretically there ought to have been an alkalinity correspond- ing t o 0.0065 gram. of SO,. To 50 cc. of the same vinegar 6-95 cc. deci-Gormal sulphuric acid were added. The alkalinity of the ash corresponded to 0.0643 per cent. of SO3, instead of 0.0565 per cent. To another 50 cc. of the same solution, 3.13 cc. of decianormal aciix were added. The alkalinity of the ash corresponded t o 0.0776 per cent. of SO,, theoretically 0*081 per cent. The allkalinitg of an ash is diminished in exact proportion to the amount of mineral acid added to the vinegar ; alkaline reaction is the surest and safest criterion, that free mineral acid is absent froin the vinegar. The final conclusion to be drawn from these results is obvious.

ISSN:0003-2654    

DOI:10.1039/AN8760100105

出版商:RSC    

年代:1876

数据来源: RSC

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THE ANALYST. 109 THE FRAUDULENT COLOURBTIQN OF WINES, BY A. GAUTIER, Bull. SOC. Chim, [2] xxv. 435-44 483-498, and 530-538. TIIE increasing practice of adding artificial colouring matters t o wines, led the author t o undertake a series o f experiments, having for object the discovery of a method by which each of these adulterants might be recognised by characteristic reactions, even in the deep red wine themselves when the amount of the fraudulent colouration did not exceed 12 to 20 per cent.of the total colouration of the liquid. I n many instances the processes to be described led successfully to the detection of a mixture of two or three colouring matters added to wines. The experiments were repeated with authenticated genuine samples of wines. COLOURIING MATTERS USED I N THE ADULTERATION OF WINES.The colouring matters which are used, sometimes to freshen or increase the natural 1. Hollyhock Althea rosea, variety nigra, petals.-They give an extract of a fine colour of red wines, sometimes to colour whits wines, at the present time are- deep wine-violet colocr.110 THE ANALYST. 2. Eldwberries (sucambzccos niger), the juice of which becomes wine red by fer- mentation or by the action of acids, much used in north and central France, Portugal, and Spain.I t s tone is heightened with tartaric acid, but more fre- quently with alum. Sdmetimes the berries of the dwarf elder fsucamhucos ebulus) are employed. The juices of both these Eldere are purgative in moderate doses. 3. Privet Berries (i2gustruaz. vzclgare) impart a crimson tint when recently added, or after fermentation, but if the juice is fermented the colour is that of an old red wine.4. Portugal Berries (Phytolacca decandra).-Their use is now almost abandoned, because the juice contains a drastic purgative. 5 . Thortle Berries.-Chiefly used in Paris, or in Switzerland to colour white wines, but not in the wine growing districts.6. Decoction of beet root; seldom used alone, it being generally employed to mask the tints of cochineal, and of fuchsine. 7. Logzuood.-There are several varieties, one of which gives reactions closely resembling Bmzil wood. When added t o new wines it imparts t o them an appearance of age. 8. Brazil Wood (alcoholic extract of).-Used for same purposes as logwood, but not employed in the prGducing districts.9. Cochineal, (carmine, carmine lake, ammoniacal carmine. )--Very largely employed, chiefly in central France to raise the tone of wines, which are in turn themseves frequently used to adulterate the mines of Burgundy and Bordeaux. I t is usually sold in thick solution in ammonia, or in cakes made by wetting the cochineal with ammonia and then pressing it.10. Fuchsine, aniline reds and violets, not unfrequently contaminated with arsenic, are used in large quantities either alone or mixed with various other yellow or red substances to diminish the brilliancy of‘ their tint. 11. Grenat:--A bye product in the manufacture of Fuchsine, (a few years ago valueless, but now sold at a remunerative price in consequence of its use for the adulteration of wines.) It consists of a mixture of mauve aniline, crysotoluidine, fuchsine, and an undetermined body called brown grenat.12. Indigo-carmine or ceruleine, in paste, added to common mines deepens their colour, and renders them purple or violet. 13. A few substances are sold under fantastic names, such as I‘ colourine,” ‘ I caramel,” ‘‘ colouring fluid,” &c., consisting of fuchsine reaidJes, mixed with beetoroot extract, carmine, &c., &c.The order of the importance of the colouring matters most frequently employed, is a8 follows :-1. Fuchsine. 2. Cochineal. 3. Holljhock. 4, Elder. 5 . Indigo. The greater part of the colouring matters communicate a rose, red, or rich violet tint to the wines, which frequently is fugitive, and in the wines thus tinted the foreign colouring matters soon separate and carry with them a portion of the natural colouring matters ; this is specially noticeable when cochineal, indigo, or fuchsine are the adulterants. Not much employed in France.Chiefly used in Paris for common wines. Tolerably largely’ used in Central France.THE AN,4LYST. 111 REACTIONS CHABACTERISTIC O F THE NATURAL COLOURS O F WINES.There are slight variations in the reactions with the products of different vines, and particularly with the age of the wine. The following apply to wines of Central France, more especially of Bourgogne, and of the Gironde, examined as they are usually sold, about five to eighteen months after the vintage, when they are said to be made, but not aged.Curbonnates of Sodu.*-A very dilute solution of di-sodium carbonate affords a means of recognizing certain adulterations. Thus elder (wall wort), dwarf elder, privet and hollyhock change to green or grey blue ; whortle berry, Portugal berry, and beetroot retain their colour ; among those which change to green with the neutral carbonate of soda, hollyhock undergoes the same change with bicarbonate while both elders are unchanged, 5 C.C.of a 1-200 solution of di-sodium carbonate, added t o 1 C.C. of natural wine afford a greenish-grey, green, or bluish-green colour, depending upon the age and variety of wine. I n certain sorts, a winey or lilac tint remains ; teinturier affords a deep bluish-green tint, which becomes chestnut brown on heating. All the following reactions were performed on the wines clarified by a process to be shown further on; or else diluted with five to ten times their volume of water, so that the colours were reduced to a mere rosy tint.The changes of colour should be observed about two minutes after the addition of the re-agents. 8odiwn Bicarbonate, charged with car6onic acid --(Eight per cent. by weigit solution,) Equal volumes of wine, and of this re-agent afford a slightly cloudy iron-grey liquid, with tint of bottle green.Teinturier becomes deep green; aramon rose winey brown ; aramon with petit Boztschet lilac changing at 100a to the colour of extract of tea. Borax.-Saturated solution at 1 5 O . One volume of wine with two volumes of this re-agent becomes bluish-grey, or that colour with greenish tinge (pifzot 16 months old ; carignane 5 months) ; greenish (cariynane) or greyish-blue with feeble violet tiage (cwignane, 18 months old) ; or entirely wine-liIac, (aramon alone, or with petit Bozcschet.) The colours should be viewed by transmitted light reflected from a white surface ; they last unchanged for several hours.Amwonia.-Ten rolumes of ordinary ammonia with 90 of water.The deeply coloured wines of Central France, mixed with an equal volume of dilute ammonia, change t o greenish grey, bottle green, greenish-y ellow, or grey greenish blue. With aramon (of which the colouring matter differs most from that of the generality of wines,) or with mixtures containing it, the change is to buff, or decoction of tea with trace of lilac.With new mines the colour is more decide17 green, but changes subsequently t o brown ; with those over a year old the colour is that of a dead leaf, if the wine is very dark coloured (like Roussillon), and the grape had become perfectly ripened, a single drop of a stronger ammonia causes a blue colouration or precipitate ; then the colour changes as before mentioned to greenish or brown.&&hide of Ammoniu?nn.--8 C.C. of ordinary ammonium sulphide, with 10 C.C. of ammonia, made up to 1 litre, with water. Equal volumes of the wine, and the re-agent are mixed and filtered. The filtrate is greenish with pure wines, but bluish or violet- lilac with those adulterated. The re-action is not satisfactory. * I n the preparation of the re-agents, the directions given must be foilowed strictly t o the letter in order to avoid errors otherwise inevitable.112 THE ANALYST.Baryta Vater.-Saturated solution. Equal volumes of this reagent and clarified or diluted wine afford on filtration an olive green, or dirty greenish yellow filtrate, sherry coloured with teinturier, old brandy coloured with aramon of 18 months. This filtrate becomes rose on acidification with acetic acid, except with teinturier, which remains buff, and aramorn which becomes clear yellowish green. It becomes red-brown, or yellow-brown with logwood, or Brazil wood.Siihncetccte of lead.-2 c c of wine with 1 C.C. of solution of subacetate of lead, of 1 5 O B give a coloured precipitate from which no indication of the nature of the coiouring matter can be obtained.When filtered the filtrate is colourless with wine, and most vegetable colouring matters ; but rose or lilac with Brazil wood ; pale rose with fuchsine. Szcbhurozcs acid.-It has been stated by various authors that any wine, the colouring matter of which was not destroyed by this re-agent might be considered to be adulterated, but in fact, whereas many vegetable colouring matters are so destroyed, that of wine remains unaffected even after 24 hours.Nascent Hi,ldrogen (by the action of hydrochloric acid on zinc), affords no satisfactory reaction. Barium Peroxide.-3 C.C. of clarified or diluted wine acidified with five drops of a 5 per cent. solution of tartaric acid, and treated with 0.1 grammes of barium peroxide is nearly discoloured in 24 hours.With elder (both varieties) fuchsine, Brazil mood, logwood, beetroot, and cochineal, the colour remains for a very much longer time. BEBCTIOXS FOR DISTINGUISETNG MIXTURES O F WINE AND COLOURING MATTEKS. The first portion of this section is devoted t o a review of the various methods that have been suggested for detecting the foreign colouring matters in wines. Having examined them all, the author avers that they are valueless.Among them are the process of Faur6 (who suggested the precipitation of the natural colouring matter in wine, with tannin, and examining the filtrate therefrom for the artificial ones,) and of Dr. Facon (decolourisation of the wine by manganese peroxide.) A tolerably successful method is to put into the suspected wine skeins of silk o r wool variously mordanted with such mordants as alum with cream of tartar, oxy- chloride of tin, and acetate of alumina. Cert,ain differentiating characteristics were thus obtained, but the method cannot be generalized; yet by mordanting scoured silk with tartaric acid, fixing the colour and drying it at looo, after having acted upon it with various reagents, such as ammonia, lime-water, chlorides of zinc, iron, calcium, salts of copper and tin, some new re-actions were obsarred, which are characteristic of certain colouring matters. [TO be cont.inued.) C.H.P.

ISSN:0003-2654    

DOI:10.1039/AN8760100109

出版商:RSC    

年代:1876

数据来源: RSC

摘要:

112 THE ANALYST. THE LATEST CHEMICAL DISCOVEBY. THE Chemical News, of the 18th inst., startles us with the wonderful announcement that (‘ an establishment has been opened in Belgium for extracting “ the wool from grease, (we think this chemical curiosity justifies the italics, which are our own), and that the c‘yield” of wool We regret that the exact details of the process are not given as they would doubtless be interesting, but possibly the method resembles in some degree that used for the extraction of sunbeams from cucumbers. is understood to be large.” The marvels of Science certainly appear to be illimitable.

ISSN:0003-2654    

DOI:10.1039/AN8760100112

出版商:RSC    

年代:1876

数据来源: RSC

摘要:

THE ANALYST. 113 REVIEWS OF BOOKS, Brc. THE ANALYST’S ANNUAL NOTE BOOE, 1875, EDITED BY S. W. RICE.“ THIS little manual contains in a portable form a number of collected articles on the analysis of a variety of substances, and, while it may be of use for reference to chemists in general, it will be found of most value to those who have not the time or the opportunity for consulting Chemical Journals as they are published.compilation of papers which have already been published, but it contains much valuable information on the analysis of such substances as bread, butter, milk, tea, citric acid, water, wine, &c. While appreciating the discriminating care with which Mr. Rich has made his selection, we cannot but express our regret that his regard for the ethics of journalism has not suggested to him the propriety of stating in each case the source to which he is indebted for the article he publishes, and also of indicating in which instances (if in any) an article is reproduced in its entirety, and in which it is merely an arbitrary abstract.It is, of course, only We will explain what we mean by an example or two. More than six pages are devoted to a paper by professor Wanklp, on the ‘( Detection of Alum in Bread.” No intimation is given that this is merely an abstract, and no acknowledgment is made of the fact that these six pages are “cribbed” from the published volume of ‘‘ The Proceedings of the Society o f Public Analysts.” We must refer those who wish to read the whole of the paper to that volume.Precisely the same remark applies to a paper.(‘ On taking the melting point of Butter, by Dr. Tripe, which is taken from the same source without any acknowledgment, and cut down at the will of the compiler. A very valuable paper on Butter Analysis by Xr. Angell, is treated in the same way-emasculated, and inserted with no acknowledgment of’ the source from which it is taken. A paper by Nr.W. C. Young, on the Volumetric estimation of Chlorides in the presence of Alkaline Phosphates, is treated with the same unfairness, as also is a paper by Dr. Redwood, on ‘‘ The Analysis of ?&ilk,” one by Dr. Stevenson, on The decompo- sition of Milk,” one by Mr. Allen, on ‘‘ The Adulteration of Tartaric and Citric Acids,” as well as Nr. Wiper’s exhaustive paper on (( Tea,” and Dr.DuprB’s valuable essay on “ The Natural Constituents of Wine.” The only thing that can be said in palliation of this wholesale system of appropri- ation, is that our compiler has been fairly unfair all round. To amateur chemists and those only desiring to obtain a smattering of the subjects treated of, this book will be useful. To the numerous chemists who posses the ‘‘ Proceedings of The Society of Public Analysts,” it will appear to a great extent a recliaufi! of that work, and to those chemists who, not having already read the papers in question, have a wish t o study them with a view to actual manipulation, we need hardly point out the wisdom of their possessing themselves of the papers in their entirety, with the discussions which in most cases ensued.We wish this little compilation all the success it deserves; but we would suggest to Mr. Rich, that he would be no loser, and his readers would be gainers, if in his next issue he were to frankly acknowledge to what sources he is indebted for his articles, and, where they are abstractions, if he would mention the fact, and state by whom they have been abstracted. Chemists mould then know what value to attach to the abstractions as faithfully representing the views of the respective authors. +BUTLER & TANNER, Frome.

ISSN:0003-2654    

DOI:10.1039/AN8760100113

出版商:RSC    

年代:1876

数据来源: RSC

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114 THE ANALYST. CORRESPONDENCE. To THE EDITOR OF THE “ANALYST.” SIa,-Will you allow me space for a few words in answer to some of the remarks made during the discussion on my paper on Butter Fat, read before the Society of Public Analysts, on June 14th, and which appears in the last number of (( The Analyst.” I believe every one is now convinced that a high specific gravity, taken by itself, is no proof of the purity of any given sample of butter.I entirely dissent from Dr. Muter’s historical sketch. What may or may not have been done in the privacy of laboratories we know not. We must, therefore, confine ourselves t o published records. Here we have firstly Messrs. Hehner and Angell’s pamphlet on butter, which is undoubtedly the foundation of our present butter analyses, secondly my note confirming the main features of Messrs.Hehner and Angell’s work, read before the Society of Public Analysts in January, 1876. Thirdly, Dr. Muter’s papers read March 15th, 1876, which, like my own previous note, is ewentially nothing more than a confirmation of Messrs. Hehner and Angell’s statement; and lastly my paper of June 14th. The experimental demonstration of the fact that butter fat really does contain a notable proportion of soluble fatty acids is the main point; the methods by means of which this is ascertained have but of secondary importance.Next I look upon Dr. Muter’s method for the estimation of the soluble fatty acids as greatly inferior to either of the three described in my paper, and also as more complicated than the one finally adopted.It will be recollected that Dr. Muter arrives at the proportion of soluble acids by means of three distinct estimations, each differing from the others in principle. First, the total free acid is estimated in ‘/5 of the bulk by standard alkali. Secondly, the total amount of sulphuric acid is estimated in of the bulk by precipitation with barium chloride.Thirdly, the total combined sulphuric acid is determined in l/lo of the bulk, by evapor- ation and final ignition of the residue, which residue is taken as potassium sulphate. Assuming that no mistake is made in the various measurements, the following may, I think, be looked upon as reasonable experimental errors. First, variations in the a m u n t of alkali necessary to neutralize the 200 cub.cents. ‘will not be less than 0.1 cub. cent., equal t o 0 5 cub. cent. on the litre, corresponding with the alkali used by Dr. Muter, to 0.026 grams butyric acid. Secondly, any one strictly following Dr. Muter’s directions, will have worked well if he comes within 1 per cent. of the total amount of sulphuric acid present, equivalent (taking the one experiment given in full by Dr.Muter as basis) to 0.088 grams butyric acid. Thirdly, few will come t o within 1 per cent. of the true amount of combined sulphuric acid present by following Dr. Muter’s directions, i n which no allowance is made for any impurity in the potassium hydrate employed, which is never absolutely pure, and, worse still, no account is taken of the fact that on ignition of the dry iesidue obtained by evaporation, much carbon is separated which has to be burnt off and reduces some sulphate to sulphide. Now 1 per cent.on the combined sulphuric acid is equivalent to 0.07 grammes of butyric acid. The sum of these errors, which I am sure ha-re not been exaggerated, is 0,184 grams of butyric acid, equal to 1-814 per cent. on the 10 grammes butter fat taken.What now is the probable error to which the process of titration is liable? I n this the total amount of soluble acid is estimated by means of a process which involves the measurement of 25 cub. cent. normal soda, of 25 cub. cent. of acid,THE ANALYST. 115 slightly above the normal, and the volumetric estimation of the excess of acid present in the mixture by means of deci-normal soda.Any one of average skill will be able to do this and come always within 0-2 of decinormal soda, but let us assume that the variation amounts to 0.5 cub. cent.” 0.5 cub. cent. deci-normal soda are equivalent to 0.044 grammes of butyric acid, which, on 5 grammes, correspond to 0.088, or say 0.1 per cent., which may be taken a8 the maximum error t o which, in moderately skilful hands, this method is liable, for the process of saponification &c., &c., does not increase the error of titration.I f two successive estimations of soluble acid in a sample of butter differ by more than this, the error is due, I am convinced, not t o a mistake in the estimation of the soluble acid actually present in the washings, but t o the fact that more soluble acid has been washed out in the one case than in the other.It may fairly be asked how, if the method employed by Dr. Muter is so faulty, I explain the marvellous correspondence hct ween the duplicate analyses of the same butter fat given in Dr. Xuter’s paper. I can only answer, I cannot explain it, unless it he accidental, for even at its best Dr. Muter’s process is necessarily less accurate than the process of titration, as it involves three estimations (instead of one), each of which is liable t o error, which, whatever it may be, has to be multiplied by 5 or 10.I look upon the fact mentioned by Dr. Muter, viz. : that the sum of acids (calculating the soluble acid as butyric acid) in my analyses rarely comes up to 94 per cent., whereas in his case it comes up to nearly 95, in spite of the fact that he saponified in an open vessel and thus lost about Q per cent.of soluble acid, as a strong proof that my process is more correct than his. In conclusion I would remark that I began nay experiments on the saponification with standard alkali in the Autumn of 1875, that in my communication to the Society of Public Analysts, in January of this year, I stated that I had made experiments in that direction, and was then engaged in similar experiments, which I hoped would be more accurate than the former, a3 well as more easy of execution.This meeting took place two months before the reading of Dr. Muter’s paper. The method is, in fact, nothing more than an application of Berthelot’s well known process for the titration of ethers, with which I have worked for ten years or more.Yours, &c., A. DUPB6. XILE OF SULPHTTR. T O THE EDIIOR O F THE “khALYST.” sm,-Referring to Dr. ‘Hill’s Paper” on Milk of‘ Sulphur, which he read before the Society of Public Analysts, as reported in your last number, I gather from it, that Dr. Hill’s contention is, that when he wants t o buy the sulphur precipitatum of the British Pharmacopoeia of 1867, he, as a medical man, is at liberty to ask for it, either by the name of precipitated sulphur, or by the name of milk oE sulphur.I n reply to this, I desire to point out that though the two names in former Pharma- copceias may have synonymously applied to the precipitate thrown down by sulphuric acid, and to that thrown down by hydrochloric acid, the British Pharmacopceia of 1867 plainly and clearly shews that the hydrochloric acid preparation alow shall be called by the name of precipitated sulphur.* 0.5 cub. cent. of deci-normal soda is equal to 0.05 cub. cent. normal soda, which is about 1 drop, and according t o Dr. Muter, would when calculated to per centaga of butyric acid give an enormous error.I16 THE ANALYST Dr.Hill therefore, as a medical man, isnot at liberty to embarrass tho retailer by asking for milk of sulphur, if he wants precipitated sulphur, and there can be no question that he is pharmaceutically reprimanded if he does so, in proof of which I give the following extract from the preface of the British Pharmacopceia of 186’7. ‘(By the Medical Act of 1858, section 54, it is enacted that the General Council shall cause to be published under their direction a book containing a list of medicines and compounds.And by a subseqnent Act, the 25th and 26th Vic., cap. 91, recites that different pharmacopceias having been published in England, Scotland, and Ireland, the pharmacopmia to be published is intended to supersede the above mentioned pharmacopceias.The present work, therefore, is produced in compliance with and under the sanction and authority of these Acts of Parliament, and is intended to afford to the medical profession, and those engaged in the preparation of medicines throughout the British Empire, one uniform standard and guide, whereby the nature and-composition of substances to be used in medicine maybe ascertained and determined.It mill be seen by the above ‘( extract,” that all former Pharmacopceias, including of course the names of all drugs, and all processes for the compounding of medicines, have been superseded, and that the ORE CODEX for the making, dispensing, and prescrib- ing of medicines is the British Pharmacopceia of 1867, in order that prescribers and dispensers may mutually understand each other.A grave responsibility therefore rested upon Dr. Hill, in flatly disobeying his pharmacopeia when he told his man to ask for precipitated sulphur by a name which is not in that work, and he, is the wrong doer, and not the unfortunate rstailer, who, when he was asked for milk of sulphur, sold milk of sulphur. Dr. Hill seems to exult, that when his man went round to the chemists’ shops t o ask for milk of sulphur, out of thirteen purchases, ten of the retailers gave for it the precipitated sulphur, thrown down by hydrochloric acid, and the wonder is, the whole thirteen did not sell that preparation aft,er receiving a certain circular, of which the following is a copy.SPECIAL NOTICE. “As the Borough Analyst is obtaining samples of milk of sulphur from chemists and druggists in Birmingham and district, it is desirable to save annoyance that only the pure precipitated sulphur should be supplied .” This curious circular was sent to all the chemists by an influential firm, and it appeared to me in plain English to mean, “ When the Borough Analyst’s man asks for an article, take his money, but to save annoyance, give him something else ! ” Yours, &c., BIRNING HAM, ALFRED BIRD, F.C.S. JuZy 26t12, 1876. (The above letter reached us too late for publication in our last issue, but the subject being of interest to Chemists in general, we iizsert it now.)

ISSN:0003-2654    

DOI:10.1039/AN8760100114

出版商:RSC    

年代:1876

数据来源: RSC

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I16 THE ANALYST - VOLUMETRIC DETERMINATION OF PHENOL. By W. F. KOPPESCHAAR. Zeitschr: F. Aizal. Chemie. 111.) 1876. ON the addition of an aqueous solution of bromine t o liquids containing Phenol, a precipitate is thrown down, consisting of Tribromophenol. According to Landolt, this precipitation is still perceptible in a solution containing, 1 part of Phenol in 43,700 parts of water ; and accordingly this substance possesses a high degree of insolubility.Experiments have proved, that the action of Bromine upon Phenol takes place according to the formula C, H, 0 -+ 6 Br. = C6 H, Br, 0 4- 3 H Br. But on account of the difficulty of collecting, washing, and drying this precipitate, a direct gravimetrical determination of the phenol cannot thus be accomplished, the tribromophenol being very voluminous and volatile at looo C.THE ANALYST.117 But according to the numerous experiments of the author, Phenol may be deter- mined with great accuracy, volumetrically, by ascertaining indirectly the quantity of Bromine which combines with a known quantity of the substance t o be examined. He prepares an aqueous solution of bromine, and determines its strength by titrating, by means of hyposulphite of soda, the iodine separated from iodide of potassium, by a measured volume of the bromine solution.A clear solution of the sample to be analysed, is prepared by dissolving 4 grammes in 1000 cc. of water, the liquid being filtered, if necessary 25 cc. of this solution are put into a stoppered bottle, capable of holding 500 cc.A measured volume of the bromine solution, containing more bromine than is necessary to effect the reaction is added, and the liquid is allowed to rest for about a quarter of an hour. Iodide of potassium is now added, and the iodine is determined as usual by means of hyposulphite of soda. Thus the necessary data are obtained t o calculate the percentage of c6 H6 0 in the sample.As it is both inconvenient and somewhat inaccurate to operate with Bromine water, a slight loss by evaporation being hardly avoidable, the author made a series of observations, employing the mixture of bromide and bromate of potassium, obtained by saturating caustic potash with bromine, and liberating from this mixture the bromine by means of hydrochloric acid. The results obtained in this manner are highly satisfactory. This latter modification is especially recommended when many samples of Phenol hare to be examined. Thus the bromine acts in a nascent state. 0. H.

ISSN:0003-2654    

DOI:10.1039/AN8760100116

出版商:RSC    

年代:1876

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THE ANALYST. 117 OFFENCES UNDEE THE SALE O F FOOD AND DRUGS ACT. ADULTERATED BUTTER IN GLASGow.-Mr. M’ Hinnon, Provision dealer, was charged under the Food and Drugs’ Act, with having sold a pound of adulterated butter. The assistant sanitary inspector stated that he obtained the butter from M’Kinnon’s shop, and that it had been anaiysed by Dr. Clark, one of the city analysts, who found that it was adulterated with extraneous fat to the extent of two-thirds of its weight, Dr.Clark, city analyst, stated that he made his analysis by Rell’s and Muter’s method, which he believed were correct, Dr. Stevenson Macadam, Edinburgh, stated that he had made an analysis of a sample of the butter by Muter’s mode and by the old system of testing. By the former the butter appeared to be adulterated, and according to the old system it was quite sound.He believed the old system was the correct one, and that the butter was quite good. Dr. Dittmar, Profcssor of Chemistry in the Andersonian University, gave similar evidence as the result of the two processea of analysis. He did not think Muter’s system was the correct one, and was of opinion that the butter a a s quite sound.A portion of the sample w8s ordered to be sent to Somerset House, and on the adjourned hearing judgment was given. The Somerset House Analysis was as follows, water 14.30 per cent., curd and impurities 0.48 per cent., salt 3-81 per cent., and fats 81.41 per cent, The analysts add that they are of opinion that the sample is made up almost exclusively of a fat which is not that of bntter, and which has apparently been worked up with a little milk.The defendant was fined two gpineas, and the cost of the Somerset House Analysis. ALUM IN BaEAD.-fit the Wednesbury Police-court, John Hartill, was summoned for selling adultera- ted bread. Mr. Jones, the County analyst, stated that upon analysing the bread he found that alum had been used to enable defendant to use damaged flour, and to make a presentable loaf, and to prevent further decomposition of the gluten and other substances in the flour.Mr. Sheldon, in defence of the accused, said that his client was extremely sorry for what had occurred, and would take care that the offence was not repeated. The Stipendiary said that if defendant repeated the offence he would be liable to be sent to the assizes or the sessions.The defendant was fined $25 and costs. MTLK ADuLTERATioN.-william Mason, of Homerton, was summoned for selling adulterated milk, The inspector sent it to the parish analyst, and put in the certificate from that gentleman to the effect that the milk was adulterated with 20 per cent. of water. The defendant made a novel detence, viz., that he had during the hot weather to put ice into the milk to preserve it.Mr. Barstow said he m i d not take xhat excuse. Ice was well known to be congealed water. It was no excuse to a butcher if he sold stinking meat, He ordered the defendant to pay a fine of f 3 and 2s. costs. AT the Brentford Petty Sessions, two dairymen, named Harris Thompson and Chas. Stanley, appeared to answer to adjourned summonses for uulawfully selling milk adulterated with water, I n Thompson’s case the milkin question, on being analysed by Dr.liedwood, was found to consist of 82 parts milk and 18 parts water. After further evidence the defendant was fined 3 7 including costs, the justices intimating that they were determined if possible to put a, stop to such practices, The case of the other defendant was very similar, and after hearing the evidence, including that of Dr.Redwood, the justices, after consdtation, imposed a fine of &ci including costs.118 THE ANALYST. On May 26th, at Chesterfield County Police Court, Arthur Slater, druggist, of New Whittington, was summoned under section 6 of the Sale of Food and Drugs Act, for selling a which vas not of the cature, substance, and quality demanded by the purchaser.Lieutenant-Colonel Shortt, inspector for North Derbgshire, said that on May 9th he instructed his assistant to take a prescription to the defendant’s shop and have it made up. At the same time he told him to ask for two ounces of ‘6 precipitated sulphur.” He wrote down the name of the article in the assistant‘s note book so that there might be no mistake.He subsequently went into the shop and told the defendant that he intended to take them to the county analyst, Mr. A. H. Allen, of Sheffield. He offered to divide them into three parts, and this offer the defendant accepted. There was no label on the sulphur. He said “You sell this as ‘precipitated sulphur’ I suppose,” and the defendant repiied in the affirmative.He sub- mitted the articles to the analyst, and subsequently received a certificate (produced) which stated that the sainple did not consist of precipitated sulphur, but of orange sulphuretted antimony, which was a very active remedy, and if taken in quantity by mistake for precigtated sulphur would have had a dangerous and probablr fatal effect, Job Bayes, assistant-inspector, stated that he asked the defendant for ‘(precipitated sulphur ” as he had been instructed, and the defendant said, ‘( Precipitated sulphur of antimony, I suppose you mean ? ” He replied, “ I don’t know ; I was told to ask ‘ precipitated sulphur.’ ” He was certain he did not mention antimony ; he bad never heard of such a preparation.I n defence i t was contended that the two preparations were totally dissimilar, and the defendant who had been a dispensing chemist for thirty years could not have made such a mistake, but the purchaser must have asked for the antimonial preparation.Mr. Gabriel, surgeon, gare evidence in favour of the defendant, who, he said, dispensed many prescrip- tions for him, and he had always found him accurate.No druggist could make the ignorant mistake alleged. WEeTMwsma.-Pennlty for refusing t o serve a Food hpector.--Edward IIunt, cheesemonger, o t 200, Vauxhall bridge-road, was summoned for refusing to supply one of the sanitary inspectors of the Board of Works for the Westminster district, a certain article of food, to wit, butter.-It appeared from the evidence of Mr.Hughes that, in his official capacity, he went to the shop of the defendant, and was served with half a pound of butter at sixteen pence per pound. He toR the defendant that he had purchased the butter for the purpose of analysis, whereupon the defendant snatched i t from him, and said he could not afford to sell it at the price. Witness had purshased butter before at this shop at the same price, and found i t genuine.-Defendant said there was a doubt on his part whether it was genuine or not and he had since discovered that it was genuine.-Mr.Arnold fined him $5, giving the alternative of a month’s imprisonment. GREENVVICH.-George Francis Sillcott and Calvin Dennis Smith, tradesmen, carrying on business as grocers, appeared to summonsed at the instance of the vestry authorities at Rotherithe, charging them with selling butter as an article of food, which, on analysis by Dr.Muter, was proved to have been adulterated to the extent of 25 per cent of foreign substance, but which was not injurious to health, The charges were proved by the inspector, the butter in question being purchased at the rate of 1s. 2d. per lb. Mr. Pook, who appeared for Smith, produced invoices received in payment of the butter, and said i t mas retailed as it was bought.The defendant Sillcott made a like defence. Mr. Yatteson told the defendants that they should obtain warranties as to the genuineness of the butter they purchased from the vendors, and fined them 20s. and 2s. costs. At the West Bromwich Police Court, on Saturday, before the Hon.A. G. Calthorpe, Major Williams, Mr. J. A. Kenrick, and Dr. Underhill, the charges against Mr. Gough and Mr. Leighton, milkdealers, of West Bromwich, for an alleged adulteration of milk, were again heard. The cases had been twice adjourned, on the first occasion for the sainples of milk to be tested by the officials of the Inland Revenue Department, Somerset House, London, and on the second occasion for the cherriical analysts from London to attend and be cross examined in respect of their certificates. The Government analysts, in their certificates, admitted that the samples were in an advanced state of decomposition, but made allowance for that in their results, which, in one case, showed that there were 8.14 per cent.of solids, not fat, 3.50 per cent of fat, and 88.36 per cent.of water. The analysts, in their report of this case, concluded as !allows : ‘L When the necessary allowance for the solids not fiat lost by the decomposition of the milk has been made, the amount is lower than is present in samples of milk of first quality, but not less than is frequently found in genuine milk of low quality. The quantity of fat represents a milk of first quality, and exceeds the proportion found in many genuine milks.This, in our opinion, is an important part in judging as to the character of the sample. Under these circumstances, we do not feel jpstified in pronouncing the milk adulterated with water.’’ I n the other case, the chemists were unable to express a definite opinion as to whether the milk was adulterated with water, The eertifioates were signed by three of the Government analysts,- Mr. Young now appeared for the prosecution, which had been taken out at the instance of Mr. Horder, inspector under the Adulteration of Food Act, who was present, together with Mr. Jones, the county analyst, who had certified that the milk was adulterated. He read what Colonel Shortt had written for him. The magistrates considered the case proved, and inflicted a fine of 32 10s. and costs. The defendants said that, such warranties, when asked for, were refused, Both cases were dismissed.

ISSN:0003-2654    

DOI:10.1039/AN8760100117

出版商:RSC    

年代:1876

数据来源: RSC