摘要:

JANUARY 1935 Vol. 60 No. 706 THE ANALYST PROCEEDINGS OF THE SOCIETY OF PUBLIC ANALYSTS AND OTHER ANALYTICAL CHEMISTS AN Ordinary Meeting of the Society was held at the Chemical Society’s Rooms, Burlington House on Wednesday December 5th Professor W. H. Roberts, Vice-president being in the chair. Certificates were read in favour of :-Henry Dryerre Ph.D. M.R.C.S. , L.R.C.P. Ronald William Hoff A.R.C.S. A.I.C. Laurance John Sidney Lane, B.Sc. Alfred Edward Wright. The following were elected Members of the Society :-Arthur James Amos, Ph.D. B.Sc. A.I.C. Harry Ronald Fleck A.I.C. Walter Lee A.I.C. Edward Burdon Parkes M.Sc. A.I.C. Francis Cecil Storrs B.Sc. A.I.C. James Thompson, F.I.C. Ph.D. Robert Sinclair Watson A.I.C. The following papers were read and discussed:-“The Question of Tannin in Mate,” by W.A. Woodard and A. N. Cowland (Work done under the Society’s Analytical Investigation Scheme) ; “ A Specification for Enamelled Hollow-ware,” by J. H. Coste F.I.C. and D. C. Garratt B.Sc. Ph.D. F.I.C.; “Antimony Compounds extracted from Enamel-ware by Citric Acid Solutions,’’ by R. H. Burns B.Sc. A.I.C.; and “Chemical Examination of the Seeds of Santalum album of Mysore,” by Y. V. S. Iyer. NORTH OF ENGLAND SECTION A MEETING of the above Section was held in Manchester on December 8th 1934. The Chairman (Prof. W. H. Roberts) presided over an attendance of thirty-one. The following papers were read and discussed:-“The Effect of Grinding in the Power Mill on the Albuminoid-content of Feeding Stuffs,” by F. Robertson Dodd F.I.C.and C. Robertson Louden B.Sc. F.I.C.; “The Examination of Ginger,” by G. D. Elsdon B.Sc. F.I.C. and Catherine Mayne B.Sc. A.M.C.T. ; and “ The Hortvet Freezing-point Process for the Examination of Milk Correction Factors and the Influence of Stirring,” by J. R. Stubbs M.Sc. F.I.C. 2 DEFINITIONS OF VINEGAR AND MALT VINEGAR Deaths WITH deep regret we record the deaths of the following members of the Society: Robert Rattray Tatlock Past-President (an Obituary Notice will be Daniel John O’Mahoney (Public Analyst for Cork). George Egerton Scott-Smith (Public Analyst for Chesterfield). published later). THE PRESIDENT’S ANNUAL ADDRESS IN the past it has been customary for the President to deliver an annual address a t the end of each year of his office. The Council has considered the matter and has decided that in future the President shall be relieved of having to deliver the first of these addresses and that in its place some distinguished member of the profession shall be invited to address the Society.The Council has pleasure in announcing that Dr. Dyer will give the first of these addresses at the Annual General Meeting on March 6th when he will give some reminiscences of the Society and its members. The meeting will be at 8 p.m. and Dr. Dyer’s address will follow the business proceedings. DEFINITIONS OF VINEGAR AND MALT VINEGAR THE following definitions are suggested standards for vinegar and malt vinegar agreed as the result of deliberations between the Society of Public Analysts and Other Analytical Chemists and the Malt Vinegar Brewers’ Federation : Vinegar is a product of the alcoholic and acetous fermentation of a saccharine solution without any intermediate distillation except in the case of Spirit Vinegar as defined in (iv).Malt vinegar should be derived without intermediate distillation wholly from malted barley with or without the addition of entire cereal grain malted or othqwise the starch of which has been saccharified by the diastase of malt. When vinegar is demanded a purchaser should be supplied with malt vinegar unless due notification is given to the purchaser of the article supplied. The name ‘‘ Vinegar ” may be applied to other products which comply with the definition of vinegar (No. (i) above) provided a prefix is used to denote the origin of the product ; thus “ Distilled Vinegar,” “ Spirit Vinegar.” Distilled vinegar is the product of the distillation of vinegar as defined in No.(i) above and its source should be denoted; such as distilled malt vinegar. Spirit Vinegar is the product of the acetous fermentation of a distilled alcoholic fluid DISCUSSION ON QUANTITATIVE SPECTROSCOPY 3 (v) “ Imitation ” or “ Artificial ” Vinegar should in every case be sold specifically marked “ Imitation ” or “ Artificial ” Vinegar It is any substitute for vinegar containing acetic acid which is not wholly the product of alcoholic and subsequent acetous fermentation and shall not contain any acid other than acetic acid. All Vinegars and Imitation or Artificial Vinegars shall contain not less than 4 per cent. w/v of acetic acid. They shall not contain any acid other than acetic acid or those acids produced by normal fermentative processes. Caramel may be used as a colouring matter in all Vinegar and in “ Imitation” or “ Artificial” Vinegars. (vi) (vii

ISSN:0003-2654    

DOI:10.1039/AN9356000001

出版商:RSC    

年代:1935

数据来源: RSC

摘要:

3 Discussion on Quantitative Spectroscopy and its Analytical Applications (Held at the Meeting on November 7 1934) INTRODUCTION BY J. J. Fox O.B.E. DSc. F.I.C. THE object of the present discussion is to bring before chemists of this Society certain spectroscopic methods now available for everyday use in the laboratory. Modern instruments are convenient to use and capable of giving readily reproducible results. Ever since Bunsen’s time the spectroscope has served for the detection of certain elements and investigation of the ultra-violet spectrum has increased the utility of the method to chemists. Recent work has placed quantitative emission and absorption spectroscopy on a firm basis, so that it is now possible to detect and determine elements and compounds with speed and accuracy.It can be affirmed that among the great advantages of the spectrographic method of analysis are permanency of record and the fact that in most cases the material examined is available for other tests. It must be borne in mind that the present-day utility of spectrographic methods is due largely to the pioneer work of Mr. Twyman and the firm with which he has been associated in producing instruments of high precision. The papers which follow amply illustrate the scope and accuracy of the method. GOVERXWENT LABORATORY CCEMENT’S INN PASSAGE LONDON W.C. 4 DISCUSSION ON QUANTITATIVE SPECTROSCOPY INSTRUMENTS USED FOR SPECTRUM ANALYSIS AND ABSORPTION SPECTROPHOTOMETRY BY F. TWYMAN F.INsT.PHYs. F.R.S. It would be interesting to survey the historical steps in the development of spectrum analysis and to enquire why since the principles of spectrum analysis and the spectroscope were available in 1861 even now after the lapse of three-quarters of a century spectroscopic methods are still not in general use by analysts in any part of the world.Since much ground has to be covered however I have confined my remarks strictly to a description of the external features of instruments actually in use to-day for spectrum analysis and absorption spectrophotometry. Fig. I Constant Deviation Wave-length Spectrometer SPECTRUM ANALYSIS BY EMISSION SPECTRA.-FOr visual work the instrument in general use is the Constant Deviation Wave-length Spectrometer shown in Fig. I, In this instrument the collimator and telescope are fixed and the spectrum is traversed past an index in the eyepiece by a screw.To this screw is fixed a drum, C on which the wave-length of the line under observation is read off directly as shown in Fig. 11. One thus obtains a wave-length scale over a metre in length. Such an instrument is suitable for rapid reference in the chemical laboratory. Most of those who practise spectrum analysis use a quartz spectrograph, which photographs not only the part of the spectrum from wave-length 400 t 2ig. IV Spectrum with wave-length scal I;ig. IX. Photograph taken with Spekker Photomete TWYMAN INSTRUMENTS USED FOR SPECTRUM ANALYSIS 5 about 819mp visible to the eye but also the range of ultra-violet spectrum from wave-length 200 to 400mp. The type of quartz spectrograph used for spectrum analysis is shown in Fig.111. This instrument is adjusted once for all and to take photographs with it is no more difficult than to do so with a hand-camera. A handle at the side serves to raise and lower the dark slide and 15 or 20 different spectra can conveniently be taken on one plate. A wave-length scale can be printed on the spectrum and is developed with the spectrum itself. The spectrum is shown in Fig. IV. Such an instrument with which the whole spectrum can be taken on a single photographic plate (lo” x 8”) is the most convenient size for general chemical work. I t is often referred to as a “ medium-size ” quartz spectrograph, but it is preferable to distinguish the size by the focal length of the camera lens for a specified wave-length-in the present case 60-cm.focus for wave-length 589mp. A larger size having three times the dis-persion is made but this requires a number of separate exposures to cover the whole range of the spectrum. Such dispersion is seldom Fig. I1 necessary in spectrum analysis if we except the analysis of steels. A small instrument having one-third the dispersion of the medium one is very useful in metallurgical work for the examination of metals with simple spectra such as brasses bronzes lead alloys and so forth; it was used by Mr. D. M. Smith in the work described in his paper (see p. 17). Wave-length Drum Fig. 111 Quartz Spectrograph 60 cm. focus ACCESSORIES.-~rcs of the metals are very easily produced provided that direct current is available.Pieces of the metal are used as electrodes; a direct current of 3 amp. or more produces an arcthat willreveal all the constituent metals. Small pieces of metal or other samples such as powders filtered precipitates dr 6 DISCUSSION ON QUANTITATIVE SPECTROSCOPY residues from solutions etc. can be examined by putting them in the scooped-out lower carbon electrode of an arc. One advantage of the carbon arc is that unlike metallic arcs it can be used with an alternating current, Numerous other ways of using the arc are available but whatever method of producing the arc-discharge is adopted a suitable form of lamp is that known as the Gramont Arc or Spark Stand (Fig. V) since it is equally suitable for using with the spark. The distinctive feature of the Gramont Stand is that after the arc or spark has been adjusted to a suitable length, the stand can be raised and lowered by means of a rack and pinion and thus aligned with the spectrograph without disturbing the discharge.For some purposes the spark i s better than the arc and the best way of obtaining it is from a &-kilowatt transformer giving secondary voltages of from 8000 to 15,000 on an open circuit. With the transformer are associated a condenser and a self-induction coil of simple character. ACCESSORIES FOR QUANTITATIVE SPECTRUM ANALYSIS.-AU endeavours to make spectrum analysis quantitative in character depend on the fact that, the greater the percentage of a metal in a sample the stronger will be the spectrum lines of that metal.Perhaps the most useful method of rendering spectrum analysis quantitative is to synthesise a specimen so that its spectrum exactly matches that of the sample. This method has been very fully worked out by Judd Lewis. I t needs no instrumental accessory except a convenient means of comparing the spectra and this is provided by the Judd Lewis Comparator. The Microphotometer has been used by some observers to measure the intensities of the lines and with due care it can yield valuable and very accurate results. In my opinion^ the apparatus which at the present time best combines convenience and accuracy is the Logarithmic Sector (Fig. VI) > This instrument is a disc of metal the periphery of which is cut into the shape of a logarithmic spiral. This is rotated in front of the slit and if the shape of the spiral is properly selected the effect is to produce on the plate spectrum lines the differences in the lengths of which are in proportion to the logarithms of the relative intensities of the corresponding radiations Fig.VII shows the appearance of such photographs. Fig. V Gramont Arc or Spark Stan TWYMAN INSTRUMENTS USED FOR SPECTRUM ANALYSIS Fig. VI Logarithmic Sector Fig. VII Spectra taken with Logarithmic Sector 8 DISCUSSION ON QUANTITATIVE SPECTROSCOPY APPARATUS FOR ABSORPTION SPECTRoPHoT0METRY.-Absorption SpeCtl-0-photometry means the measurement of the absorption of radiation by a substance for various wave-lengths so that a curve of absorption may be plotted. Such a curve is often highly characteristic of the substance (see Fig.X). The simplest way of doing this is by means of the apparatus known as the Sector Photometer, which I introduced about 1912. A large proportion of the work on ultra-violet spectrophotometry in various parts of the world has been done with this instrument, but this is now superseded by a simplified form of Judd Lewis's spectrophotometer C A -:I<-C -0- G Fig. VIII Diagram of " Spekker " Spectrophotometer (shown in Fig. VIII) which is known as the " Spekker '' Spectrophotometer.2 It is intended to be placed in front of a spectrograph such as a quartz spectrograph. Light from a suitable source of ultra-violet rays (A) passes towards the inner edges of two quartz rhombs C C from which beams are diverted upwards and downwards to be reflected forward through the tubes F F in one of which is placed the absorbing liquid and in the other the liquid with which comparison is to be made.For instance in the one tube there may be an organic substance in a solvent and in the other tube the solvent alone. The beams from the rhombs pass the one through a fixed rectangular aperture and the other through an aperture the size of which can be varied by means of a micrometer screw rotated by a drum D with an index which travels along a helix in the drum. This not only simplifies readings but also acts as a stop to prevent the drum from being turned too far in either direction. After passing through the absorbing substance and the non-absorbing substances the beams pass through lenses G G of quartz the focal length of which is such that an image of the light source is formed on the face of the slit of the spectrograph.A second pair of quartz rhombs H H is arranged to bring the beams of light together on to the slit in such a way that the image falling from the top rhomb and that from the bottom rhomb on the slit form a complete image of the light source. A number of photographs are taken one below the other with various widths of the adjustable aperture (see Fig. IX) TWYMAN INSTRUMENTS USED FOR SPECTRUM ANALYSIS 9 It will be seen that there are a number of pairs of spectra one spectrum of each pair being cut down in intensity uniformly along its length by a known amount whilst the other has its intensity locally reduced by reason of the absorption of the liquid under examination.There are certain places indicated by spots in the figure where the two spectra match and at these points if we know the width of the aperture we can deduce the absorption of the liquid. d -wa a m 2606 tm sjbg 481M M U € W Lm. &w*. T*WB. W I V R I N E t l i Fig. X. Absorption Curve of Benzene (in Hexane) Fig. X shows a curve drawn from the values obtained from the preceding photograph; it is the absorption spectrum of benzene in hexane 1 in 3300. REFERENCES 1. 2. F. Twyman and F. Simeon Trans. Opt. Soc. 1929-30 31 No. 4. F. Twyman Trans. Opt. SOL 1931-32 33 No. 1. RESEARCH LABORATORIES MESSRS. ADAM HILGER & Co. LTD. 98 KING’S ROAD N.W. 10 DISCUSSION ON QUANTITATIVE SPECTROSCOPY QUANTITATIVE SPECTROSCOPY AND ITS ANALYTICAL APPLICATIONS BY S.JUDD LEWIS D.Sc. PH.D. F.I.C. This discussion is concerned with those aspects of the subject which are of direct practical concern to the analytical and consulting chemist in general practice, rather than to those following any particular branch of the subject. In Mr. Smith’s contribution (p. 17) it will be found that it is possible to work with metals in the compact form and that everything makes for success. On the other hand non-metallurgical materials such as the ashes of plants or of textiles or the total solids of a water or a milk offer none of these advantages. They are usually much less homogeneous than alloys they are frequently incapable of taking any convenient shape they are usually inferior conductors of electricity, and they function very irregularly under the influence of any electric discharge.Moreover it is desirable to work by the arc method rather than by the spark and here one meets with difficulty of another kind namely the wandering and irregular functioning of the arc. The problem then is to formulate some method which will be suitable for such very heterogeneous materials and this has been done with a very fair measure of success in the Ratio Quantitative System of which I have already given a descripti0n.l Although the present paper is mainly concerned with the details of this system one must not lose sight of the excellent FZame work of Lundegardh2 of Stockholm in dealing with plant ashes and the like. He passes a blast of air through a solution of the ash contained in the well of a perfume spray of particular form into an acetylene blow-pipe where the mixture is burnt in front of the slit of a spectrograph.A spectrogram rich in the lines of a limited range of elements is produced. Hartley’s method for sparking solutions has been greatly improved of late by Twyman and H i t ~ h e n . ~ Mention should also be made of the method of saturating a soft carbon electrode with the solution in question and arcing on alternating current; also of Ramage’s method* of burning a weighed quantity of the substance in a rolled filter-paper in an oxy-hydrogen flame. The reasons for laying stress upon the Ratio Quantitative System by the Are method are:-(i) It is new; (ii) it is directly applicable to materials of every type to an extent not possible with any other method; (iii) it is easily controlled and rendered efficient without resort to special photometric equipment or other special devices; (iv) it records a complete quantitative survey of all the metallic elements composing the sample even when the quantity of material is very small; 5 mg.is the normal load but if one has only 1 mg. or even less of the sample the method is still valid if a like quantity of the standard is used for the comparison; (v) it is applicable both to soluble and insoluble substances. The conception of ‘‘ Ratio ” is merely mathematical but in its application to quantitative spectrum analysis the idea is that if one knows the proportion of a Every detail is rigorously controlled JUDD LEWIS ANALYTICAL APPLICATIONS OF SPECTROSCOPY 11 minor element in terms of ratio or percentage to that of a major component, the proportion of which is either known or ascertainable chemically or spectro-scopically one knows the proportion of the minor element in the sample.For example if there is in the total solids of a water 0.017 per cent. of manganese relative to calcium and there are 10 parts of calcium per 100,000 in the water there is 0.0017 part of manganese per 100,000 in the water. Moreover the ratio idea permits of still wider application for if the ratio of manganese to calcium in the ash of a plant is known it is known also in the plant or other biological material from which the ash was prepared. Experimentally the basic ideas are (i) To bring the whole sample of ash or other material into some constant homogeneous condition; (ii) to arc (or spark) under well-defined uniform control.The first of these requirements is satisfied by converting the ash into sulphates according to prescription and the second by well-controlled experimental procedure in order to render the work constant and comparable. A portion of the vegetable ash including any phosphate silicate or other insoluble matter which it may contain is treated with a small excess of sulphuric acid in a new silica crucible. The mixture is evaporated and gently ignited just sufficiently to drive off the excess of sulphuric acid. Thus the whole mass is in a condition approximating to normal sulphates “ homogeneously ” mixed with the pre-existing phosphates silica etc.I t is then mixed with an equal weight of spectroscopically pure ammonium sulphate and is ready for spectrographing. The use of ammonium sulphate secures three or four advantages (i) It supplies in effect a constant amount of sulphuric acid to the mass; (ii) it renders the mass more porous; (iii) it generally helps to regularise the action when a portion of the mixture is burnt in the arc. Ten mg. of the mixture are placed on the lower electrode of a suitable arc-lamp set in front of the slit of the spectrograph. The next step viz. that of ‘‘ striking ” the arc and exposing the mixture for a suitable time e.g. 60 seconds, is the critical operation; it must be controlled with great care if constant com-parable results are to be obtained. After development of the photograph in the usual way the first spectrogram is obtained.The same procedure is followed with 10 mg. of a suitable standard ratio powder and thus a second spectrogram is obtained; in practice however this operation is eliminated since it has already been done once for all. An inspection of the spectrogram of the ash will at once reveal its approximate composition that is to say it will be obvious that it is mainly sodium or potassium with much or little calcium and magnesium (or vice-versa) together with more or less phosphorus silicon etc. and one can then take from the file a standard spectrogram of a suitable ratio powder to serve as standard for comparison. Assume the major metallic element to be calcium and consider three standard ratio powders having calcium as a base and containing manganese lead and tin: (a) With 1 per cent.of each element relative to calcium; (b) 0.1 per cent. ; (c) 0.01 per cent. On comparison of the intensities of the manganese lead and tin lines in the The two spectra are then compared in a “Compa~ator.” 12 DISCUSSION ON QUANTITATIVE SPECTROSCOPY spectrum of the unknown mixture with those respectively in each of these standard spectra in turn one is able to determine that the manganese is just a little stronger than 0.1 per cent. or about 0.11 per cent.; that the lead is about one-third of 0.1 per cent. and three times 0.01 per cent.; therefore that the lead is about 0.03 per cent.; and that the tin is a little less than 0.01 per cent. ap-proximately 0.008 per cent. This principle is founded on both theory and laboratory experience.In using a correct mixing a condition of experiment is attained which justifies usually although possibly not always comparison of “homologous pairs” of lines by the “internal standard” method using for reference the lines of the main component not those of the electrodes. Preparation of Special Ratio Powders.-If more precise results are desired a special ratio powder may be prepared in accordance with these findings and then the deviation in each case should be so small that any remaining differences may be estimated by inspection. If still more exact figures are required they may be obtained by repeating the determination with the quantities as estimated in the second experiment. As already intimated this synthesis of a special standard is the systematic and final step but by comparing the unknown with stock ratio powders one can, for many purposes obtain readings sufficiently close without making the synthetic mixture.It must however be emphasised that in the final appeal one should have the major elements in approximately the correct proportion since the intensity of the lines of the minor element is not precisely the same when the base is mainly calcium as it is when the base is mainly sodium; and so on. This sounds perhaps a little lengthy but in practice it is not so for standard 6 r Specpure ” solutions are already available commercially. It must not be assumed, however that accurate quantitative comparisons can be made until one has acquired some experience.A most important feature of this method is that it economises time for each one of these determinations applies to the whole range of elements concerned, major as well as minor and not as in most chemical work to one only. Thus in making the synthetic mixture one adjusts by measuring out appropriate quantities of the solutions of the several metals the proportion of each one of the elements, and so in the end one finds that the synthesised spectrum is practically identical in all respects with that of the unknown ash. ACCURACY OF THE PRocEss.-It remains to show what order of accuracy may be expected from such work and in order to avoid uncertainty or unconscious bias determinations controlled by chemical work in other laboratories have been selected.(i) Iron in Aluminium.-The determination of iron in aluminium by chemical processes is frequently a matter of great uncertainty-so much so that several chemists have resorted to spectrographic methods of one kind or another and claim greater uniformity of result. With two samples the following percentages were obtained by myself and my assistant Mr. F. W. J. Garton respectively, (a) by the adopted method (b) by a distinctly modified method to see whether a marked difference of procedure prejudiced the results seriously JUDD LEWIS ANALYTICAL APPLICATIONS OF SPECTROSCOPY 13 No. 1. No. 2. Adopted Modified Adopted Modified method method Difference method method Difference Per Cent. Per Cent. Per Cent. Per Cent. Per Cent. Per Cent. A A f > f \ By S.J.L.. . 0.083 0.080 0.003 0.101 0.089 0.012 Difference . . 0.005 0.007 0.004 0.003 By assistant . . 0.088 0-087 0-001 0.097 0.092 0.005 These readings are all first-hand laboratory results without subsequent adjustment. (ii) Vanadium in Organic Material.-The next example shows that similar tolerance applies to major components as exemplified by vanadium in the ash from an industrial organic material of which only a few mg. were available. Spectroscopic Chemical Per Cent . Per Cent. Vanadium as metal 26.6 26.2 14.5 13.0 With smaller proportions of vanadium the results also agreed well e.g. 0.75, 0.76; 0.80 0.81 0.77; 0.71 0.74 per cent.; these three samples were not controlled chemically. (iii) Nickel in Organic MateriaZ.-Similarly nickel in an organic material was controlled.Spectroscopic Chemical Per Cent. Per Cent. Nickel as metal 3.5 3.0 3.6 3-3 Whilst these figures demonstrate that consistent results are obtainable spectrographically and that they are closely comparable with those determined chemically they afford no evidence as to which method is to be preferred. The following investigation with copper tends to favour the spectrographic method, since it is free from complications which beset the chemical method. (iv) Copper in a Food.-The following results in parts per million were obtained : Spectrographic Chemical 0.46 0.56 0.46 0-56 0.49 0.56 0.50 0.56 0.48 0-53 0.63 0.68 Duplicates 0.33 0.33 -0.32 0.36 -0.33 0.29 -As the chemical findings depended upon the removal of lead in an earlier stage of the process it is quite possible that the results in the subsequent colorimetric determination of copper may be a little high owing to incomplete removal of lead.The following examples illustrate work of a somewhat different class: (v) Germanium.-Germanium when present in zinc to the extent of onl 14 DISCUSSIOK ON QUANTITATIVE SPECTROSCOPY one part in 100 millions may be estimated quite well by dissolving 5 g. of the zinc in acid and co-precipitating with a suitable heavy metal by means of hydrogen sulphide filtering and incorporating homogeneously a little calcium to serve as the standard base then spectrographing in accordance with the Ratio Quantitative System and comparing the arc spectrograms with a special standard of Ge/Ca. (vi) Biological FZ.uid.-Aqueous humour 0.28 g.yielded 3-5 mg. of sulphated ash containing about 1 mg. of mixed alkali metals which was spectrographed with a known weight of spectroscopically pure calcium chloride ; upon determining the ratios Na/Ca and K/Ca it was found that the ratio NaCl/KCl was 15 1. We have no figures for human aqueous humour but for the horse the ratio 22 1 has been found.5 Apart from the ratio method it has also been shown in detail how 1 part of aluminium can be determined in one million of blood with a very fair approximation to the truth when using only a single ml. of blood and as the result of several experiments on the human subject it has been found that the blood becomes saturated with aluminium at about that concentration.6 Reference to the same spectrograms reveals the fact that silicon (in traces only) lead boron arsenic, tin and zinc are among the elements frequently occurring and that manganese, strontium barium and silver are present in only minute quantity or not at all.By following up these observations quantitatively much light may be thrown on problems depending on the inorganic chemistry of blood. APPLICATION OF SPECTROSCOPY TO CRIMINoLoGY.-Occasionally spectroscopy has been applied to criminology as illustrated by the following cases: (i) The case of the “affaire de la Bonnet Rouge.” On the boot-lace of the criminal Almereida who died mysteriously in the infirmary two stains were found. M. Bayle was asked to analyse these stains. By comparison of the spectra of (a) the unsoiled part of the boot-lace (b) the two stains (c) the paint on the bedstead in which Almereida had slept it was shown that one of the stains was due to mud and the other to paint from the bedstead.The spectrum of the first stain showed aluminium lines whilst that of the other stain showed the lines of barium zinc and lead in exactly the same way as did the spectrum of the paint. This gave the police the required information and confirmed the conclusion that Almereida had hanged himself in prison.’ (ii) Wilson,8 writing in the Journal of Criminal Law and Criminology, complains that spectroscopy has not yet found the wide use it deserves in criminal investigation and then proceeds to describe two or three interesting cases. In one of these the spectrographic analysis of a slight smear on a coat was identified with the putty from a window broken during a burglary and led to the man’s conviction.(iii) Telephone wire stolen from a Government department in Ceylon was identified spectroscopically as containing traces of certain ingredients which were present in Government stock but not in any other samples obtained locally.1° (iv) In another case also from Ceylon ‘ I 17 lead pellets and slugs were examined spectroscopically and were found to consist of five different types of lead. The same five types of lead found in these pellets from the scene of th JUDD LEWIS ANALYTICAL APPLICATIONS OF SPECTROSCOPY 15 crime were all represented in the pellets etc. found later with the weapon which was suspected of having been used.”g One must anticipate that the question will arise How far can evidence of the spectroscope be acceptable in a court of law? I have not considered this question exhaustively but my impression is that the spectroscope will provide very strong evidence when the analyst has become so familiar with the work that he can with absolute conviction swear to the results he obtains.I believe that then the evidence will be more readily accepted than is much of the chemical work since the results may be demonstrated in photographed spectra. Fig. I ABSORPTION SPECTROSCOPY.-AS time does not permit of a full description, I must ask you to allow half-a-dozen slides to speak for themselves.* The absorption curve of a special glass exhibited the narrow bands due to neodymium at 332 425 436 502 and 575mp and to praseodymium at 444, 467 and 480mp just as would a solution of salts of the two elements.This method of investigating the absorption spectra of the rare earths by spectro-photometry affords the best and most reliable means of analysing quantitatively mixtures of these and certain other elements. * Those shown were Figures 29 30 31 32 38 39 in Spectvoscopy in Science and Industry, by S. Judd Lewis (Blackie) 16 DISCUSSION ON QUANTITATIVE SPECTROSCOPY SPECTROSCOPIC DETECTION OF TEA-SEED OIL IN OLIVE OIL.-The last slide demonstrated the detection of tea-seed oil in olive oil by means of absorption spectroscopy. In Fig. I (p. 15) are seen curves for two samples of tea-seed oil, and in Fig. I1 the absorption curves for (A) pure olive oil and (B) and (C) the same olive oil to which has been added 1 per cent.and 5 per cent., respectively of tea-seed oil. It should be observed that the extinction coefficient of olive oil at a wave-length of 268mp is 11 whilst that of tea-seed oil is 690, and that of the 5 per cent. mixture 46 which is in good accord with the Fig. I1 calculated figure 690 x 0.05 + 11 x 0.95 = 46; similarly the mixture containing 1 per cent. has an extinction coefficient of 18 on the curve or by calculation, 690 x 0.01 + 11 x 0.99= 17.8 SMITH USE OF THE SPECTROGRAPH IN METALLURGICAL ANALYSIS 17 1. 2. 3. 4. 5. 6. 7. 8. 9. REFERENCES S. Judd Lewis Chem. and Ind. 1932 51 271; Sflectroscopy in Science a d Industry, 1933 (Blackie) . H. Lundegardh Die quantitative Spektralanalyse der Elemente 1929.F. Twyman and C. S. Hitchen Proc. Roy. SOC., H. Ramage Nature 1929 123 601. British Chemical Abstracts A 1933 176. S. Judd Lewis Biochem. J. 1931 25 2162. Conquest 1921 [No. 121. C. M. Wilson J . of Criminal Law and Criminology 1932,25 160. C . T. Symons ANALYST 1931 56 667; 1932 57 576. 1931 133 [A] 73. THE LABORATORIES BANK CHAMBERS 329 HIGH HOLBORN W.C.1 THE USE OF THE SPECTROGRAPH I N METALLURGICAL ANALYSIS BY D. M. SMITH A.R.C.S. B.Sc. D.I.C. INTRODUCTORY.-DUring the last ten years or so increasing use has been made of spectrographic methods in analytical laboratories not only as a check on chemical control of material but also for routine testing. With a view to en-couraging the wider adoption of these methods by metallurgists systematic investigation of the subject has been in progress by the British Non-Ferrous Metals Research Association for some years.This work has been largely concerned with testing the application of these methods to the determination of impurities in metals of commercial importance by means of a simple and inexpensive technique and equipment. It is the purpose of this contribution to describe briefly what is being done in this direction and to indicate possible future developments with a view to improving the reliability and accuracy of spectrographic analysis and to extending its scope of application. TECHNIQUE.-For the analysis of metals and alloys the quartz spectrograph is generally used qualitative and quantitative analysis being carried out by observation of the characteristic lines in ordinary photographic records of arc-and spark-spectra.Mr. Twyman has dealt in ample detail with the apparatus used in this work and there is no need therefore to enlarge on that part of the subject . As the amount of an impurity or alloying constituent increases its character-istic lines show a corresponding increase in intensity and the general principle of spectrum analysis consists of the correlation of the intensities of these lines with the amounts of the constituents giving rise to them.* While not wishing to detract from the value of purely visual methods of analysis (cf. F. Twymanl) I would point out that there are several important advantages of photographed spectra. Apart from the value of having a permanent * An illustration wits shown of the arc-spectra of the following grades of zinc:-spectro-A simple means of rapidly identifying such material is thus obtained.(The slides shown at the meeting were actual spectra obtained with a small-size spectrograph. scopically pure ; chemically pure ; electrolytic ; common spelter. In this way the inevitable IQSS of detail by reproduction was avoided) 18 DISCUSSION ON QUANTITATIVE SPECTROSCOPY record of each analysis the most sensitive lines used in analytical work are to be found in the main in the ultra-violet part of the spectrum and the most satisfactory method of examining this region is by means of photographic records. Moreover, since quantitative determinations are based on comparisons of the intensities of lines (as represented by the densities of their images on the photographic plate) the absence of colour is much to be preferred.With regard to the form of the samples the arc or spark between metallic electrodes consisting of pieces of the sample under test has much to commend it from the point of view of convenience in operation. Preliminary treatment as required in chemical analysis such as dissolving the metal and subsequently pre-cipitating is avoided. It is not always possible or convenient to prepare electrodes in a suitable form for a n arc to be obtained in this way d more use is now being made of the arc between pure graphite electrodes. The arc is more sensitive than the spark for the detection of traces of certain impurities and since it is very difficult to obtain rneta.Uk arcs with tin and lead graphite electrodes have distinct advantages for such metals.In the analysis of small copper samples Milbourn employs a similar technique but with the small modification of using a pure copper rod in place of the upper graphite electrode. STANDARD ALLoYs.-Before it is possible to standardise a spectrographic method of analysis of any given metal or alloy considerable attention must be given to the question of the reliability of the standard alloys since the method is based on the quantitative interpretation of the spectra of alloys of accurately known composition.* The most obvious method of controlling the standard alloys is to rely upon the results of careful chemical analyses checked and confirmed by the independent work of skilled analysts and in many cases this is the only method available.For metals of low m.p. such as lead tin and zinc however the melting mixing and casting of accurately weighed constituents in vawo has proved a very satis-factory method of producing alloys of definite composition. This method of preparation fails in cases where the alloying constituents tend to separate out on cooling. It is often difficult for example to obtain in this way homogeneous alloys containing even small quantities of lead. A method recently found useful for checking the reliability of chemically analysed samples proposed as standards for spectrographic work involves the use of “synthetic spectra.” The spectrum of a standard alloy containing the highest content of the series (which is easier to check by chemical analysis than a sample containing only a trace) is superimposed on that of the pure metal forming the main constituent the times of exposure being systematically varied.t * The arc-spectra of synthetic alloys of zinc with 0.75 0.25 0.1 0-01 and 0.001 per cent.of cadmium were shown as an illustration of quantitative standard spectra. t Two slides illustrating the principle of this method were shown. The two components of each synthetic spectrum were photographed separateIy and in juxtaposition in the first slide, the upper spectrum in each case being that of the standard lead alloy (lead containing 0.5 per cent. of tin) and the lower spectrum that of pure lead. The corresponding times of exposure were as follows : Lead + 0.5 per cent.of tin: Pure lead 65; 60; 45; 30; 16 ,, 6 ; 10; 16; 30; 46 seconds. By superposing the spectra in each pair as shown in the second slide a series of five spectra was obtained in which the tin lines showed a systematic increase in intensity the lines due to the 1 rirxary constituent (lead) remaining of constant intensity SMITH USE OF THE SPECTROGRAPH IN METALLURGICAL ANALYSIS 19 A curve can then be constructed showing the relation between the percentage of impurity present and the time of exposure of the standard alloy which gives a spectrum identical with that of the sample under examination. Irregularities are then readily detected from the position of individual points with regard to the mean curve. This method has been applied to the determination of small quantities of bismuth in copper,2 and it shows promise of fairly wide applicability.METHODS OF ANALYsIs.-The Necessity for Standardisation of TechniqMe.-Whether the arc or spark be used as the source of the spectrum there are a number of variables which require rigid control to secure reproducibility of the spectra. The aim has been so to choose the technique in individual applications as to be able to obtain from the spectrum of the sample itself all the quantitative information required. At the same time it should be pointed out that the method of comparing the spectrum of a sample with those of selected standard alloys (generally referred to as the “comparison sample” method) has been found extremely useful and is still very largely used particularly in testing whether a material conforms to specification.Qzcantitative Interpretation of the Spectra.-The general applicability of spectrographic methods in different laboratories under somewhat different conditions has also received attention and wherever possible the conditions for the production of the spectra have been standardised from this point of view. The basic principle underlying practically all the methods now in use for quantitative analysis was first described by W. GerlachS in 1925 and is known as the “ internal standard ” method. Equality of intensity between an impurity line and a line of the main constituent is correlated with the percentage of impurity present. If sufficient pairs of lines of this kind are available analysis is possible in fairly close steps.In a large number of cases sufficient lines suitable as internal standards are not available and in order to distinguish between more closely-graded percentages, methods using auxiliary spectra “ coupled ” with those of the samples under examination have been used as for example the tin spectrum which gives a fairly wide range of lines of different intensity. Owing to the different characters of a number of spectrum lines the use of an auxiliary aZZoy has been found to give more suitable lines as intensity standards such as e.g. an alloy of copper with 1 per cent. of tin for the analysis of copper samples. Similarly an auxiliary alloy of lead with 0.4 per cent. of tin can be used for the analysis of lead samples.* Here one is comparing impurity lines with tin lines in the auxiliary spectrum-a procedure which appears more satisfactory since both types of lines are intrinsically the same.* In order to increase the accuracy of analysis methods based on the above principles but also giving the possibility of assigning numerical values to the intensities of the lines have been devised.The recording or non-recording * Arc-spectra of alloys of copper with various quantities of manganese afforded an illustration of the internal standard method. The superposition of a tin spectrum and the juxtaposition of a spectrum of copper with 1 per cent. of tin was shown in the case of a number of copper-alloy SF ectra 20 DISCUSSION ON QUANTITATIVE SPECTROSCOPY 1. 2. 3. 4. microphotometers and the logarithmic sector-wedge methods may be quoted as examples.* Metallurgical Applications.-Considerable progress has been made in the delicacy of the chemical detection of traces of elements so that the superiority of spectrographic methods in this respect is not quite so pronounced as formerly. On the other hand the chemical determination of traces of impurities is usually laborious involving tedious separations from a large bulk of material and requiring considerable skill. It is moreover in the region of traces of impurities that the spectrograph is shown to its best advantage and about 1 per cent. may be taken as the upper practical limit of its present sphere of usefulness. In this particular field standardised methods have been developed by the British Non-Ferrous Metals Research Association for the determination of the usual impurities in zinc copper, tin lead and aluminium and work is now proceeding on the determination of the impurities commonly occurring in nickel.An excellent example of the value of spectrographic methods is afforded by the analysis of " chemical lead." It is possible to determine the copper silver, bismuth antimony zinc and cadmium contents of this material with sufficient certainty to determine whether it conforms or not to specification. The deter-mination of traces of bismuth in copper and traces of cadmium in zinc are further examples of metallurgical importance. Such analyses as these can be carried out as a matter of routine with great saving of time. Many other interesting applications might easily be enumerated of which the following are typical:-Testing material fm segregation or mon-homogeneous distribution of impurities and alloying constituents.-The fact that in spectrum analysis only a very small amount of the material takes part in the discharge becomes an advantage in this case.The analysis (for metaZlic constituents) of coatings dross inclusions and the like.-In cases such as these it is generally only possible to give little more than a qualitative analysis but with experience it is possible to distinguish between the major constituents and those occurring in very small quantities. The analysis of samples too small for chemical analysis.-The spectrographic method gives a complete qualitative if not quantitative analysis of the material. Identi$cation of material.-In addition to the rapid testing of samples of unknown composition cases are known where it has been possible to identify or indicate the source of supply or the process of refining employed by the presence of traces of residual metallic constituents (of deoxidisers for example).A large amount of valuable work has been carried out in recent years in other quarters and the laboratory of Messrs. I.C.I. Metals Ltd. may be specially mentioned in this connection. Papers giving details of standardised methods for * Logarithmic sector-wedge spectrograms were shown of lead-tin alloys containing up to 3 per cent. of tin the lengths of the tin lines increasing with increasing percentage and the lead lines remaining of fairly constant length in the different spectra SMITH USE OF THE SPECTROGRAPH IN METALLURGICAL ANALYSIS 21 the analysis of lead brass and copper have been published by Brownsdon and by van Someren5 and Milbourm! The work for the British Non-Ferrous Metals Association has been considerably assisted by this and other parallel work which has been made available.In Germany numerous publications have appeared under the authorship of Gerlach and Scheibe’ and their colleagues and in Belgium Breckpot* has recently published an account of his extensive study of the analysis of copper. Increasing attention is also being given to spectrographic methods in America and since the middle of 1933 about fifty publications (from various countries including our own) of metallurgical interest have appeared. PRESENT TENDENCIES AND FUTURE DEVELOPMENTS .-owing to the increasing and widening application of spectrographic methods several different aspects of the subject have been investigated some in considerable detail.Generally speaking, the different lines of attack both in England and abroad have been and still are, in the following three directions: (i) Towards greater stability and reproducibility of arc and spark discharges, with a view to obtaining improved regularity in the results. Valves and undamped high-frequency oscillationsQ have been used for spark circuits, for example and the intermittent arclo method has been proposed for rapidly oxidisable metals such as aluminium. (ii) Improvements in methods of “sampling” (the word sampling in this connection being taken to mean the selection of samples to be subjected to spectrographic examination) in order to extend the application of the spectrograph in quantitative analysis and to increase the reliability of the results.Solution and “ pastille ’’ methods,u oxide and sulphate powder samples have been proposed with this end in view and the method described and so successfully used by Judd Lewis may be instanced in this connection. (iii) Increase in sensitivity of detection of traces and in the accuracy of determination. The use of higher currents in the arc for example has yielded increased sensitivity in the detection of traces of bismuth and electrolytic deposition and preliminary chemical separation have given a similar increase in sensitivity. The use of photometric devices to obtain increased accuracy is also being investigated.It may be observed however that there is a danger when introducing too many refinements that the simplicity and speed of spectrum analysis wherein lie its chief attractions may be lost to a considerable extent. With simplification of photometric methods and the possibility of reducing the personal factor there is no doubt that such methods will be increasingly used. An attempt has been made to cover a wide field although restricted to metallurgical analysis and more particularly to the investigations on non-ferrous metals and alloys which have now been proceeding for nearly ten years and are still in progress for the British Non-Ferrous Metals Research Association. I t is hoped however that this contribution will have been of some general analytical interest 22 DISCUSSION ON QUANTITATIVE SPECTROSCOPY I wish to thank the Society of Public Analysts for the invitation to take part in the Symposium and the Director and Council of the British Non-FerrousMetals Research Association for permission to publish this contribution.REFERENCES 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. F. Twyman Trans. Optical SOC. 1931-1932 33 176. J . Inst. Metals 1934 55 Advance Copy No. 682. 2. anorg. Chem. 1925 142 383. British Non-Ferrous Metals Research Association Monograph No. 2 (1933). J . Inst. Metals 1931 46 97-113. Ibid. 1934 55 Advance Copy No. 680. In particular the books Die chemische Emissionsspektralanalyse (L. Voss Leipzig I, 1929; 11 1933) by W.Gerlach and E. Schweitzer and “Chemische Spektralanalyse” (in Physikalische Methoden der unalytische Chemie Akad. Verlag. Leipzig 1933) , by G. Scheibe. G. Potapenko ibid. 1933 215 44. Ann. Soc. Sci. Bruxelles 1933 53 219; 1934 54 99. Goroncy and Urban 2. anorg. Chem. 1933,211 28. W. Gerlach and others zbid. 1932 209 337 etc. K. Kellermann Arch. Eisenhzittenwesen 1929 3 205. BRITISH NON-FERROUS METALS RESEARCH ASSOCIATION REGNART BUILDINGS EUSTON STREET LONDON N.W.1 DISCUSSION Mr. J. H. GARDINER referring to the use of the spectroscope in criminology, mentioned that more than sixty years ago Dr. Meymott Tidy who was then Professor of Medical Jurisprudence at the London Hospital showed at the Royal Institution the absorption bands of blood that he had extracted from the hat of a suspected criminal; this formed a link in the evidence leading to the conviction of a man named Muller who “murdered Mr.Briggs on a railway train.” He (Mr. Gardiner) had the honour of working under the late Sir William Crookes from 1881 until his death in 1919 and during all that time the spectroscope was in constant use for the researches carried out in the laboratory. One lengthy work was the spectroscopic examination of some twenty earthy meteorites obtained from the collection in the British Museum the lines between 1np400 and 240 of all the elements present being identified. The method used‘(for they were all non-conductors of electricity) was to mix the finely powdered aerolite with pure precipitated silver and by means of a hydraulic press to form the material into blocks from which electrodes could be cut; from the resulting arc-spectra the lines due to the silver could easily be recognised and those due to the aerolite observed.For a particular research it was desired to obtain some absolutely pure iron but it proved extremely difficult in fact impossible to get. Help was given by many metallurgists and the purest specimen was one from the Bureau of Standards, Washington but even in this faint traces of the manganese lines were shown. The last work upon which Sir William was engaged was the separation of the element scandium from the rare mineral wiikite; on account of the rarity of the substance the arc-spectrum method could not be followed and the chemical work of the separation was directed by constant reference to the spark spectrum of a solution of the nitrate.The most difficult step in the work was the removal of traces of holmium that accompanied the scandium in the mineral and Mr. Gardiner exhibited the first spectrum photograph which showed that this substance had been successfully removed and (‘ Scandium Purissimum ’’ obtained. Photographs, signed by Sir William of cathode luminescence spectra of some rare earths of the yttria series were also exhibited ; in these photographs bands were observed that were thought to be due to a novel element which was provisionally named “ victorium,” but unfortunately the work was never completed THORB JARNARSON AND DRUMMOND UNSATURATED HYDROCARBON IN OLIVE OIL 23 Mr. M. MILBOURN said that he was using spectrographic methods in an industrial laboratory where they had proved themselves indispensable. Without minimising the value of quantitative work it would be well to bear in mind that much could be done without making any actual quantitative estimate. For instance the purity of chemical precipitates could be checked; or one could readily determine whether the metallic constituents of two samples supposed to be similar were really identical; or again when two samples were behaving differently, differences in composition particularly with regard to the minor constituents, could be rapidly ascertained. In quantitative work more particularly in routine analyses to specification some measure of accuracy could be sacrificed to speed, any doubtful results being checked by chemical methods. Close collaboration in the use of chemical and spectrographic analysis ensured that one method acted as a constant check upon the other. Sometimes spectrographic methods were definitely superior to chemical methods as in the determination of minute quantities of magnesium. The PRESIDENT in proposing a hearty vote of thanks to all the speakers for their contribution to the symposium asked the members to include in their thanks Messrs. Adam Hilger Ltd. for the special display of spectroscopic instruments

ISSN:0003-2654    

DOI:10.1039/AN9356000003

出版商:RSC    

年代:1935

数据来源: RSC

摘要:

. 23 Occurrence of an Unsaturated Hydrocarbon in Olive Oil BY T. THORBJARNARSON AND J. C. DRUMMOND DSc. F.I.C. IN the course of an investigation with the object of distinguishing olive oil from other oils Bolton and Williams1 came to the conclusion that the natural oils and fats could be classed in four groups according to the degree of unsaturation of their unsaponifiable matter. Olive oil was peculiar in being characterised by un-saponifiable matter with high iodine value (197 to 204). So far as we are aware there is only one subsequent investigation recorded in the literature which throws light on this peculiarity. Sani2 separated an unsaturated hydrocarbon from the non-saponifiable fraction of olive oil by dis-tillation at reduced pressure. The elementary analyses and determination of molecular weight led him to suggest the formula C,,H, for the compound but he does not appear to have determined its iodine value.His examination of this compound was cursory and suggested the importance of making a more thorough investigation of its nature. The olive oil employed for the main part of the experiment was an authentic product of Palestinian origin.* Saponification value 191 ; iodine value 82.6 ; ni80 1-4707 ; unsaponifiable matter 1.12 per cent.; iodine value of unsaponifiable matter 255; mean equivalent of fatty acids 279; iodine value of fatty acids 85-3. PREPARATION OF UNSAPONIFIABLE MATTER.-The olive oil was saponified by 30 minutes’ treatment with an excess of hot alcoholic potassium hydroxide solution. representative oils examined during the course of this investigation.It had the following characteristics : * We are greatly indebted to Mr. E. R. Bolton F.I.C. for his help in obtaining this and othe 24 THORB JARNARSON AND DRUMMOND OCCURRENCE OF AN The soap solution was diluted with three volumes of water and repeatedly extracted with redistilled ether. After the ethereal extract had been washed and the solvent distilled off the residue was re-saponified with sodium ethoxide and the extraction process was repeated. The final yield of unsaponifiable matter from 1 kg. of oil was 9.6 g. This material was a soft yellow wax with iodine value 255 and contained 16.9 per cent. of material (sterol) precipitated by digitonin. An attempt was made to separate the constituents of the unsaponifiable matter by fractional crystallisa-tion from hot methyl alcohol.For this purpose 7 g. were treated with 500 ml. of hot methyl alcohol. A small amount of the substance would not dissolve in spite of continued heating. This insoluble material was filtered off and dried. It was a dark-brown semi-solid oil (substance A) with iodine value 130. The filtrate was concentrated to half its volume and kept at 0°C. A crystalline substance of a faint yellow colour separated (substance B). It was filtered off and the filtrate was concentrated to half its volume once more and stored at 0" C. A crystalline substance separated from the concentrated filtrate, along with some oily droplets. This fraction was isolated and again taken up in a small amount of methyl alcohol the crystalline substance (C) being less soluble than the oil.The material soluble in the methyl alcohol was obtained by removal of the solvent. It was a heavy colourless oil (D) which on cooling and standing deposited a small amount of a soft waxy crystalline material. This treatment with methyl alcohol effected a considerable concentration in the more soluble fractions of the material with high iodine value. Iodine value Original non-saponifiable matter 255 Fraction (A) . . 130 Fraction (B) . . 108 Fraction (C) 181 Fraction (D) 342 These fractions were examined chemically with the result that A and B were found to consist largely of crude ** sitosterol." Further examination of these '* sterol " fractions and those obtained in the adsorption experiments later to be described showed that they consisted mainly of sitosterol accompanied by the usual small proportions of dihydrositosterol ergosterol and dihydroergosterol.Fraction D contained a large proportion of a hydrocarbon which to our surprise, appeared to resemble squalene. Naturally our main interest was centred on the last-mentioned fraction but efforts to free it completely from oxygen-containing substances by the use of solvents were not successful. It was decided therefore to try selective adsorption as a means of separating the hydrocarbon more satisfactorily. A preparation of the unsaponifiable matter was dissolved in a small quantity of a mixture of 90 per cent. of petroleum spirit (b.p. 40-60" C.) and 10 per cent. of benzene and passed slowly through a column of Merck's spxially-prepared aluminium oxide.Four coloured zones appeared and gradually moved down the column during washing with the same solvent mixture. The washing was con UNSATURATED HYDROCARBON IN OLIVE OIL 26 tinued until the lowest of the coloured zones had almost reached the bottom of the column. The aluminium oxide column was then divided into portions corresponding with the zones. Each fraction of the aluminium oxide was eluted by washing with a mixture of 75 per cent. of petroleum spirit and 25 per cent. of methyl alcohol. The iodine values of the various fractions were determined and their spectroscopic properties were examined for us by Dr. R. J. Macwalter to whom we desire to express our thanks. TABLE I 2-05 g. OF UNSAPONIFIABLE MATTER ADSORBED Weight Iodine value Absorption bands mp* g.Original unsaponifiable matter 2.05 255 307 W 297 W General absorption Filtrate material not adsorbed 1.23 345 352 W 333 s+ 324 S+ 301 S+ 286 S+ 275 M Bottom band of column. Least readily adsorbed. 2nd zone from bottom of column. 3rd zone from bottom. 0-03 0.02 209 190 349 w 326 W 295 W 282 W 270 M 260 M 303 W 289 W 277 edge 0.34 130 Moderate general absorption Top zone of column. Most 0.43 104 294 M strongly adsorbed. 281 M 261 V.W. * W signifies weak band; M signdies band of moderate intensity; S signifies well-defined The spectroscopic examination of the fractions revealed interesting information. The bands exhibited by the adsorbed material from the top of the column indicated clearly the presence of ergosterol.They were also seen sharply when the material from the next zone (3rd) was recrystallised from methyl alcohol but were masked in the examination of the crude fraction by general absorption due in large part to the presence of a pigment of the xanthophyll type. The spectroscopic properties of the hydrocarbon fraction will be referred to again later. The fraction of the unsaponifiable matter which passed unadsorbed through the column was a colourless and odourless mobile oil. From it there appeared, on standing in a cool place a small amount of a crystalline waxy substance which was readily separated and which after one recrystallisation from methyl alcohol, showed no absorption of iodine and melted indefinitely at 68".On analysis it absorption 26 THORB JARNARSON AND DRUMMOND OCCURRENCE OF AN gave the following results :-*Carbon 84.10; hydrogen 14.77 per cent. (4.714 mg. gave 14.35 mg. of carbon dioxide and 6.22 mg. of water). This analytical result, together with the properties of the material strongly suggest that it is a mixture of saturated aliphatic hydrocarbons similar to the preparations isolated by Chibnall and his colleagues from a variety of plant materials (e.g. a mixture of C, H, and CS1H6% m.p. 63-4" C. isolated by Chibnall and Sahai3 from the wax of brussels sprouts). The amount of the saturated hydrocarbon preparation was insufficient to provide for a more thorough examination. A sample of the liquid fraction which remained behind after the solid hydro-carbon had been removed was analysed.The results indicated that a great part consisted of an unsaturated hydrocarbon possibly of the squalene type but that very small traces of other substances some of which contained oxygen were aiso present. Bromination in anhydrous ether solution or treatment with hydrochloric acid gas in dry acetone gave crystalline derivatives which bore a superficial resemblance to the dodecabromide and hexahydrochloride respectively of squalene. It has been found impossible satisfactorily to free the unsaturated hydrocarbon from the saturated hydrocarbons and other substances by distillation under reduced pressure. After removal of the saturated component as described above distillation at low pressure effects a satisfactory purification of the unsaturated hydrocarbon.In the fractionation of 4 g. at a pressure of 0.08 mm. most of the liquid passed over in the range 170' C. to 190" C. and a considerable proportion of this was collected between 187" and 190" C. The distillation effected considerable purification of the hydrocarbon as judged not only by the analytical results but also by thespectroscopic examination. The crude hydrocarbon fraction as reference to Table I will show exhibited a number of absorption bands. The nature of the substance responsible for these has not been determined but it is of interest to note that the group of bands recorded here has also been detected in this laboratory in the corresponding fraction from wheat-germ oil. The band at 275mp may possibly be referred to carotene, but the others are more probably related to a cyclic unsaturated hydrocarbon.Further work on this question is in progress. The distilled hydrocarbon showed a much simpler picture as only three poorly-defined bands at 324,292 and 281mp, were detected. So far as we have been able to determine these bands are due to minute traces of impurity. They are not we believe related to the main hydro-carbon constituent. The distilled fraction was a clear colourless mobile fluid. On analysis it gave the figures Carbon 87.53 87-71; hydrogen 12.62 12.44 per cent. (calculated for C,H, C=87.70; H=12.30 per cent.). It is interesting to notc that the analytical data recorded by Sani are in agreement with these figures (C=:87-45 87.79; H= 12.20 11-80 per cent.).He undoubtedly isolated almost purt squalene but was misled by a low figure for his molecular weight deter-mination. He noted absorption of halogens but did not observe the formation of crystalline derivatives. HydrochZoride.-In dry acetone saturated with hydrochloric acid gas the distilled hydrocarbon gave a good yield of a crystalline derivative. The crude * Elementary analyses recorded in this paper were carried out by Dr. Ing. Schoeller of Berlin and by Dr. G. Weiler of Oxford UNSATURATED HYDROCARBON I N OLIVE OIL 27 hydrochloride melted rather indefinitely between 112" and 120" C. recalling the similar behaviour of squalene hydrochloride as described by several authorities, This compound was found to contain 33-61 per cent. of chlorine (calculated for C,OH&~~ = 33-86 per cent.).It was purified by fractional crystallisation from acetone after the manner described by Heilbron Kamm and Morton4 in their studies of the squalene hydrochlorides. The less soluble fractions gave rise to a material of a high m.p. (148-9' C.) which did not change its character on subsequent treatments with the solvent. In a recent experiment one fraction melting as high as 150" C. was obtained.* The main part of the more soluble portion gave a well-defined product melting unsatisfactorily between 118" C. and 124" C. but small amounts of preparations melting as low as 109' to 111" C. and even looo to 101" C. were obtained from mother liquors. The results of this fractionation resemble those obtained when squalene hydrochloride is similarly treated (Andrd and Canal,5 Heilbron et ~ 1 .~ ) . The analysis of the two main fractions gave the following figures: Hydrochloride m.p. 148-9" C. Chlorine 33-14 per cent. , , 100-1" c. , 33-54 > Y Fig. 1 shows the crystalline form of the hydrochloride (m.p. 110-116" C.) and that of squalene isolated from the liver oil of Scymnorrhinus Zichia. a. Hydrochloride from hydrocarbon derived from olive oil. b. Squalene hydrochloride. Bromide.-The hydrocarbon dissolved in anhydrous ether and treated with an excess of bromine at -25" C. deposited a white micro-crystalline product superficially resembling the dodecabromide of squalene. The separated bromide darkened at 150" C. and melted with signs of decomposition at 187-189" C. The * There would appear to be need for a re-investigation of the isomeric hydrochlorides of Fractionation of the crude hydrochloride may yield a wide range of crystalline products squalene.with different melting-points. Other workers have also noted this peculiarity 28 THORB JARNARSON AND DRUMMOND OCCURRENCE OF AN percentage of bromine found on analysis was 69.7. (Calculated for C,HaBr,,; Br = 69.7 per cent.) PREPARATION OF HYDROCHLORIDE DIRECT FROM OLIVE OrL.-It being apparent, from the iodine value of the unsaponifiable matter and also from the actual yield of the hydrocarbon that the latter was present in this sample of olive oil to the extent of approximately 0-5 per cent. it seemed of interest to attempt the pre-paration of the hydrochloride directly from the oil itself.Actually the attempt was successful in that characteristic crystals of this derivative separated out when the acetone solution of the oil was subjected to treatment with dry hydro-chloric acid gas. The yield was however less than one-third of what might have been expected and the experiment considered as an analytical test for olive oil WAS unsatisfactory because of the separation of layers and the production of a large amount of dark brown pigmented material. When heated the hydro-chloride thus produced and purified by washing with anhydrous ether showed shrinkage at llO°C. and finally melted rather indefinitely between 120" and 129" C. PROPORTION OF THE HYDROCARBON IN OLIVE OILS OF DIFFERENT ORIGIN.-A number of genuine olive oils of known origin and one authentic sample of tea-seed oil were examined for the presence of the hydrocarbon.The oils were saponified as described earlier in the paper and the iodine values of the unsaponi-fiable matter were determined. The unsaponifiable fractions were then dissolved in a mixture of 75 per cent. of light petroleum spirit and 25 per cent. of benzene, and passed through a column of adsorbent aluminium oxide. The columns were washed through with a solvent mixture of similar proportions and the materials which passed through without being adsorbed were recovered. The iodine values of these were determined. It will be seen from the following table that all the samples of olive oil gave fractions which passed through the adsorption column and which consisted almost entirely of the hydrocarbon.The presence of the hydrocarbon was in each case confirmed by the preparation of the crystalline hydrochloride. The results of the examination of the sample of tea-seed oil gave no evidence that squalene or any similar compound was present. The chlorine-content was 33.22 per cent. TABLE I1 Oil Iodine value of unsapopifiable matter Palestine . . 255 Tunisian . . 194 Spanish (Aragon) 203 Turkish . . 263 Italian . . 235 Tea-seed . . 157 " Hydrocarbon " in unsaponifiable matter Per Cent. 64 38 31 58 -7" Iodine value of " hydrocarbon" fraction 345 360 374 364 130 -* In view of the low iodine value of the hydrocarbon fraction from tea-seed oil it is im-probable that any significant amount of squalene is present UNSATURATED HYDROCARBON I N OLIVE OIL 29 COMPARISON OF PROPERTIES OF OLIVE-OIL HYDROCARBON AND SQUALENE Hydrocarbon from olive oil Recorded data for squalene C,H, Composition C= 87-8 per cent.C= 87-71 87.53 per cent. l3.p. loo 235-7°C. (0-kmm.) (a) 187-190" C. (0.08 mm.) Refractive index ?zD 1.4965-7 (a b c d) 1.4964 Iodine value 367.9 (b) 377.6 (d) 372 Mol.wt. cryoscopic 394-391 (b) 391 (d) 368 (benzene) Hydrochlorides H= 12-2 H= 12.62 12-44 m.p. 144-5" C. C1=33-9 per cent. m.p. 1444' C. C1=332 ,, m.p. 107-8' C. C1=33.9 ,, m.p. 144-5' C. C1=33*7 ,, m.p. 113-4" C. C1=33.85 , (d) darkens a t 160°C. melts with Br = 69.7 per cent. (b) m.p. 148-9" C. C1=33-84 per cent. m.p. 100-1" C. Cl=33.5 per cent. m.p. 107-8' C. C1=35-3 , (e) m.p. 109-11' C. -m.p. 107-8" C. C1~33.6 ,, Dodecabromide darkens a t 160' C. melts with Br= 69.7 per cent. decomposition a t 185" C. decomposition a t 187' C. (a) (b) (c) (a) (e) Majima and Kubota Jap. J. Chem. 1922 1 9. Chapman J. Chem. Soc. 1917 56; 1918 468. Tsujimoto J. Chem. Ind. Tokio 1906 9 953; J. Ind. Eng. Chem. 1916 8 889; 1920, Heilbron Kamm and Morton J . Chem. Soc. 1926 1630. Andr6 and Canal Compt. vend. 1925 181 612. 12 63. REFERENCES 1. 2. 3. 4. 5. E. R. Bolton and K. Williams ANALYST 1930 55 6. G. Sani Atti Accad. Lincei 1930 12 238. P. N. Sahai and A. C. Chibnall Biochem. J. 1932 26 403. I. M. Heilbron E. D. Kamm and R. A. Morton J. Chem. SOC. 1926 1630. E. Andre and H. Canal Compt. rend. 1925 181 612. UNIVERSITY COLLEGE UNIVERSITY OF LONDO

ISSN:0003-2654    

DOI:10.1039/AN9356000023

出版商:RSC    

年代:1935

数据来源: RSC

摘要:

WILLIMOTT AN INVESTIGATION OF SOLANINE POISONING 439 DISCUSSION The PRESIDENT remarked that it seemed somewhat strange that potatoes in certain states (old potatoes, green potatoes, etc.) were often described as highly toxic to stock. Many hundreds of tons had been used as stock feed, and he had never actually known of any stock poisoning. Of course, it could be argued that the potatoes used for feeding were often cooked, and much of the solanine dissolved out, but, on the other hand, a large number of these potatoes were used uncooked, and, therefore, stock did consume this vegetable with its full content of solanine, and, so far as he knew, without detriment. During the war a circular was issued, stating that potatoes were an injudicious feed for horses, and setting out the maximum amount that should be given.However, potatoes had been given to horses in limited quantities without bad results. Mr. C. E. SAGE said that cases of solanine poisoning were not infrequent, but he knew of no fatal one, caused by eating the bright red berries of Solanum dulcamara, which grew plentifully in this country. Solanum nzgrum, which had white flowers and black fruits, were sometimes eaten by country children, but he had never met with any casualties. Until recently the fruits of Solanum carolinense were used in America for the preparation of a tincture for medicinal use. I t grew plentifully as a weed in the Southern States, and the orange-coloured fruits were known as Sodom apples. The alkaloids, solanine and solanidine, existed in the fruits, and, as the negroes had used it for a long time as a remedy for falling sickness, the alkaloid could not be particularly toxic, although it was undoubtedly potent. Solanum chenopodium was a native of Queensland, and some thirty years ago he had isolated the alkaloid solanine from it.In Brazil, S. aculeatissimum was the plant yielding Sodom apples. It also contained solanine. With all these sources of solanine, and with potatoes and tomatoes containing it, there seemed to be no great danger from its toxicity. The leaves of S. nigrum were boiled and eaten in the Hawaii Islands, and the fruits known as “fox’s grapes’’ could be eaten in small quantities without any harmful effects. With sprouting potatoes it did not seem beyond the bounds of possibility that some product of decomposition might have caused the illness of people recorded in the paper.Mr. W. PARTRIDGE said that his only experience in the determination of solanine was in connection with a case in which it was alleged that potatoes had been tampered with and had caused illness. He had used the Meyer process, as outlined by Harris and Cockburn (ANALYST, 1918,43, 133) , but with the improve- ments (including the correction for solubility in ammonia wash-water) of Borner and Mattis (ANALYST, 1924, 49, 284). The potatoes in question, substantial areas of which were green, contained 19 mgrms. of solanine per 100 grms. Taking the attitude that normal potatoes contained about 2 mgrms., and never niore than 8 mgrms. per 100 grms., and that 25 mgrms. per 100 grms. were known to be dangerous, he had felt justified in associating the symptoms, minor though they were, with green potatoes.Mr. E. M. HAWXINS remarked that there seemed to be something in the wisdom of old-fashioned country folk. Thirty years ago when, fresh from the town, he went to live in a rural district, the old country folk instructed him that a potato which was allowed to get green through exposure above the earth was likely to be dangerous to human beings and to animals, and he, therefore, never used them. He thought it significant, in the Glasgow case, that more solanine was contained in potatoes which were green from exposure to sunlight than in the white tubers, and the paper certainly bore out this same contention.WILLIMOTT AN INVESTIGATION OF SOLANINE POISONING 439 DISCUSSION The PRESIDENT remarked that it seemed somewhat strange that potatoes in certain states (old potatoes, green potatoes, etc.) were often described as highly toxic to stock.Many hundreds of tons had been used as stock feed, and he had never actually known of any stock poisoning. Of course, it could be argued that the potatoes used for feeding were often cooked, and much of the solanine dissolved out, but, on the other hand, a large number of these potatoes were used uncooked, and, therefore, stock did consume this vegetable with its full content of solanine, and, so far as he knew, without detriment. During the war a circular was issued, stating that potatoes were an injudicious feed for horses, and setting out the maximum amount that should be given.However, potatoes had been given to horses in limited quantities without bad results. Mr. C. E. SAGE said that cases of solanine poisoning were not infrequent, but he knew of no fatal one, caused by eating the bright red berries of Solanum dulcamara, which grew plentifully in this country. Solanum nzgrum, which had white flowers and black fruits, were sometimes eaten by country children, but he had never met with any casualties. Until recently the fruits of Solanum carolinense were used in America for the preparation of a tincture for medicinal use. I t grew plentifully as a weed in the Southern States, and the orange-coloured fruits were known as Sodom apples. The alkaloids, solanine and solanidine, existed in the fruits, and, as the negroes had used it for a long time as a remedy for falling sickness, the alkaloid could not be particularly toxic, although it was undoubtedly potent.Solanum chenopodium was a native of Queensland, and some thirty years ago he had isolated the alkaloid solanine from it. In Brazil, S. aculeatissimum was the plant yielding Sodom apples. It also contained solanine. With all these sources of solanine, and with potatoes and tomatoes containing it, there seemed to be no great danger from its toxicity. The leaves of S. nigrum were boiled and eaten in the Hawaii Islands, and the fruits known as “fox’s grapes’’ could be eaten in small quantities without any harmful effects. With sprouting potatoes it did not seem beyond the bounds of possibility that some product of decomposition might have caused the illness of people recorded in the paper.Mr. W. PARTRIDGE said that his only experience in the determination of solanine was in connection with a case in which it was alleged that potatoes had been tampered with and had caused illness. He had used the Meyer process, as outlined by Harris and Cockburn (ANALYST, 1918,43, 133) , but with the improve- ments (including the correction for solubility in ammonia wash-water) of Borner and Mattis (ANALYST, 1924, 49, 284). The potatoes in question, substantial areas of which were green, contained 19 mgrms. of solanine per 100 grms. Taking the attitude that normal potatoes contained about 2 mgrms., and never niore than 8 mgrms. per 100 grms., and that 25 mgrms. per 100 grms. were known to be dangerous, he had felt justified in associating the symptoms, minor though they were, with green potatoes.Mr. E. M. HAWXINS remarked that there seemed to be something in the wisdom of old-fashioned country folk. Thirty years ago when, fresh from the town, he went to live in a rural district, the old country folk instructed him that a potato which was allowed to get green through exposure above the earth was likely to be dangerous to human beings and to animals, and he, therefore, never used them. He thought it significant, in the Glasgow case, that more solanine was contained in potatoes which were green from exposure to sunlight than in the white tubers, and the paper certainly bore out this same contention.WILLIMOTT AN INVESTIGATION OF SOLANINE POISONING 439 DISCUSSION The PRESIDENT remarked that it seemed somewhat strange that potatoes in certain states (old potatoes, green potatoes, etc.) were often described as highly toxic to stock.Many hundreds of tons had been used as stock feed, and he had never actually known of any stock poisoning. Of course, it could be argued that the potatoes used for feeding were often cooked, and much of the solanine dissolved out, but, on the other hand, a large number of these potatoes were used uncooked, and, therefore, stock did consume this vegetable with its full content of solanine, and, so far as he knew, without detriment. During the war a circular was issued, stating that potatoes were an injudicious feed for horses, and setting out the maximum amount that should be given. However, potatoes had been given to horses in limited quantities without bad results.Mr. C. E. SAGE said that cases of solanine poisoning were not infrequent, but he knew of no fatal one, caused by eating the bright red berries of Solanum dulcamara, which grew plentifully in this country. Solanum nzgrum, which had white flowers and black fruits, were sometimes eaten by country children, but he had never met with any casualties. Until recently the fruits of Solanum carolinense were used in America for the preparation of a tincture for medicinal use. I t grew plentifully as a weed in the Southern States, and the orange-coloured fruits were known as Sodom apples. The alkaloids, solanine and solanidine, existed in the fruits, and, as the negroes had used it for a long time as a remedy for falling sickness, the alkaloid could not be particularly toxic, although it was undoubtedly potent.Solanum chenopodium was a native of Queensland, and some thirty years ago he had isolated the alkaloid solanine from it. In Brazil, S. aculeatissimum was the plant yielding Sodom apples. It also contained solanine. With all these sources of solanine, and with potatoes and tomatoes containing it, there seemed to be no great danger from its toxicity. The leaves of S. nigrum were boiled and eaten in the Hawaii Islands, and the fruits known as “fox’s grapes’’ could be eaten in small quantities without any harmful effects. With sprouting potatoes it did not seem beyond the bounds of possibility that some product of decomposition might have caused the illness of people recorded in the paper.Mr. W. PARTRIDGE said that his only experience in the determination of solanine was in connection with a case in which it was alleged that potatoes had been tampered with and had caused illness. He had used the Meyer process, as outlined by Harris and Cockburn (ANALYST, 1918,43, 133) , but with the improve- ments (including the correction for solubility in ammonia wash-water) of Borner and Mattis (ANALYST, 1924, 49, 284). The potatoes in question, substantial areas of which were green, contained 19 mgrms. of solanine per 100 grms. Taking the attitude that normal potatoes contained about 2 mgrms., and never niore than 8 mgrms. per 100 grms., and that 25 mgrms. per 100 grms. were known to be dangerous, he had felt justified in associating the symptoms, minor though they were, with green potatoes. Mr. E. M. HAWXINS remarked that there seemed to be something in the wisdom of old-fashioned country folk. Thirty years ago when, fresh from the town, he went to live in a rural district, the old country folk instructed him that a potato which was allowed to get green through exposure above the earth was likely to be dangerous to human beings and to animals, and he, therefore, never used them. He thought it significant, in the Glasgow case, that more solanine was contained in potatoes which were green from exposure to sunlight than in the white tubers, and the paper certainly bore out this same contention.

ISSN:0003-2654    

DOI:10.1039/AN9356000029

出版商:RSC    

年代:1935

数据来源: RSC

摘要:

OF MILK: CORRECTION FACTORS AND THE INFLUENCE OF STIRRING: I1 h I11 225 It was originally intended to employ four different amounts of supercooling for each sample of milk, vix. about 1.5, 1.0,0.8, and 0.5" C. It was found, however, that the differences in the readings of the thermometer corresponding to these different amounts of supercooling were in the neighbourhood of 0.002"-an amount so small that the unavoidable errors of observation might possibly approach the same order. It was, therefore, decided to employ only two different amounts of supercooling, as widely apart as practicable, say about 1.5" and 04", and to increase the number of samples examined. It was stated by Hortvet that, unless a much greater amount of supercooling than 0.5" is employed in the use of his cryoscope and technique, the rise of the mercury column is not sufficiently pronounced, and that there is more or less wavering, so that difficulty arises in deciding on the exact point at which the top of the column becomes stationary. Elsdon and Stubbs (Eoc.it.)^ found the same result when using a supercooling of less than about 0.8"; the mercury rose very slowly, and did not maintain a steady position for any appreciable time, and the proper freezing-point might not, under these circumstances, be attained. In the first experiments, made with the object of ascertaining the super- cooling correction, it was observed that where the amount of supercooling was small, that is, less than say 0-75", even in the absence of alcohol in the jacket surrounding the freezing-tube, the rise of temperature, when freezing occurred, was very slow-so slow, indeed, as to suggest doubts whether the thermometer would indicate the freezing-point of the milk, influenced only by supercooling, owing to the reading being affected by the length of time which elapses and the possibility of imperfect thermal insulation, causing a nett loss of heat from the freezing tube and contents.To give an instance; in an experiment when the supercooling was 0-71" the time required for the mercury column to rise until, on observation through the telescope with the aid of the horizontal cross-wire, the ascent became imperceptible, was 92 minutes, as compared with about 3& minutes when the same milk was super- cooled 1-49'. It will be seen later that, in the absence of alcohol in the space surrounding the freezing-tube, the heat insulation of the milk is not perfect; a nett loss of heat occurs, for it is possible t o carry through a freezing-point determination under such conditions.The difference between the two methods of working- with and without alcohol-results in a longer time being required for the cooling of the milk when the space around the freezing-tube is occupied by air. There were also the difficulties of judging when the rising column of mercury had reached the highest point, due to the very slow movement which occurred in that region, and of getting satisfactory readings, owing to the short time that elapsed before a fall took place. The idea of following strictly the Hortvet technique, as regards stirring, for these particular experiments was therefore abandoned.In the first series of experiments, the results of which are recorded in Table 111, four or five stirrings of three strokes each were employed, and in the second series the mechanical stirrer, working at the rate of 40 strokes per minute, was in operation all the time, the thermometer rising until tapping became necessary. It does not appear that these variations in stirring caused any significant differences in the results obtained, but the times of rising of the mercury, after two different extents, large and small,OF MILK: CORRECTION FACTORS AND THE INFLUENCE OF STIRRING: I1 h I11 225 It was originally intended to employ four different amounts of supercooling for each sample of milk, vix.about 1.5, 1.0,0.8, and 0.5" C. It was found, however, that the differences in the readings of the thermometer corresponding to these different amounts of supercooling were in the neighbourhood of 0.002"-an amount so small that the unavoidable errors of observation might possibly approach the same order. It was, therefore, decided to employ only two different amounts of supercooling, as widely apart as practicable, say about 1.5" and 04", and to increase the number of samples examined. It was stated by Hortvet that, unless a much greater amount of supercooling than 0.5" is employed in the use of his cryoscope and technique, the rise of the mercury column is not sufficiently pronounced, and that there is more or less wavering, so that difficulty arises in deciding on the exact point at which the top of the column becomes stationary.Elsdon and Stubbs (Eoc. it.)^ found the same result when using a supercooling of less than about 0.8"; the mercury rose very slowly, and did not maintain a steady position for any appreciable time, and the proper freezing-point might not, under these circumstances, be attained. In the first experiments, made with the object of ascertaining the super- cooling correction, it was observed that where the amount of supercooling was small, that is, less than say 0-75", even in the absence of alcohol in the jacket surrounding the freezing-tube, the rise of temperature, when freezing occurred, was very slow-so slow, indeed, as to suggest doubts whether the thermometer would indicate the freezing-point of the milk, influenced only by supercooling, owing to the reading being affected by the length of time which elapses and the possibility of imperfect thermal insulation, causing a nett loss of heat from the freezing tube and contents.To give an instance; in an experiment when the supercooling was 0-71" the time required for the mercury column to rise until, on observation through the telescope with the aid of the horizontal cross-wire, the ascent became imperceptible, was 92 minutes, as compared with about 3& minutes when the same milk was super- cooled 1-49'. It will be seen later that, in the absence of alcohol in the space surrounding the freezing-tube, the heat insulation of the milk is not perfect; a nett loss of heat occurs, for it is possible t o carry through a freezing-point determination under such conditions.The difference between the two methods of working- with and without alcohol-results in a longer time being required for the cooling of the milk when the space around the freezing-tube is occupied by air. There were also the difficulties of judging when the rising column of mercury had reached the highest point, due to the very slow movement which occurred in that region, and of getting satisfactory readings, owing to the short time that elapsed before a fall took place. The idea of following strictly the Hortvet technique, as regards stirring, for these particular experiments was therefore abandoned. In the first series of experiments, the results of which are recorded in Table 111, four or five stirrings of three strokes each were employed, and in the second series the mechanical stirrer, working at the rate of 40 strokes per minute, was in operation all the time, the thermometer rising until tapping became necessary.It does not appear that these variations in stirring caused any significant differences in the results obtained, but the times of rising of the mercury, after two different extents, large and small,OF MILK: CORRECTION FACTORS AND THE INFLUENCE OF STIRRING: I1 h I11 225 It was originally intended to employ four different amounts of supercooling for each sample of milk, vix. about 1.5, 1.0,0.8, and 0.5" C. It was found, however, that the differences in the readings of the thermometer corresponding to these different amounts of supercooling were in the neighbourhood of 0.002"-an amount so small that the unavoidable errors of observation might possibly approach the same order.It was, therefore, decided to employ only two different amounts of supercooling, as widely apart as practicable, say about 1.5" and 04", and to increase the number of samples examined. It was stated by Hortvet that, unless a much greater amount of supercooling than 0.5" is employed in the use of his cryoscope and technique, the rise of the mercury column is not sufficiently pronounced, and that there is more or less wavering, so that difficulty arises in deciding on the exact point at which the top of the column becomes stationary. Elsdon and Stubbs (Eoc. it.)^ found the same result when using a supercooling of less than about 0.8"; the mercury rose very slowly, and did not maintain a steady position for any appreciable time, and the proper freezing-point might not, under these circumstances, be attained.In the first experiments, made with the object of ascertaining the super- cooling correction, it was observed that where the amount of supercooling was small, that is, less than say 0-75", even in the absence of alcohol in the jacket surrounding the freezing-tube, the rise of temperature, when freezing occurred, was very slow-so slow, indeed, as to suggest doubts whether the thermometer would indicate the freezing-point of the milk, influenced only by supercooling, owing to the reading being affected by the length of time which elapses and the possibility of imperfect thermal insulation, causing a nett loss of heat from the freezing tube and contents. To give an instance; in an experiment when the supercooling was 0-71" the time required for the mercury column to rise until, on observation through the telescope with the aid of the horizontal cross-wire, the ascent became imperceptible, was 92 minutes, as compared with about 3& minutes when the same milk was super- cooled 1-49'.It will be seen later that, in the absence of alcohol in the space surrounding the freezing-tube, the heat insulation of the milk is not perfect; a nett loss of heat occurs, for it is possible t o carry through a freezing-point determination under such conditions. The difference between the two methods of working- with and without alcohol-results in a longer time being required for the cooling of the milk when the space around the freezing-tube is occupied by air.There were also the difficulties of judging when the rising column of mercury had reached the highest point, due to the very slow movement which occurred in that region, and of getting satisfactory readings, owing to the short time that elapsed before a fall took place. The idea of following strictly the Hortvet technique, as regards stirring, for these particular experiments was therefore abandoned. In the first series of experiments, the results of which are recorded in Table 111, four or five stirrings of three strokes each were employed, and in the second series the mechanical stirrer, working at the rate of 40 strokes per minute, was in operation all the time, the thermometer rising until tapping became necessary.It does not appear that these variations in stirring caused any significant differences in the results obtained, but the times of rising of the mercury, after two different extents, large and small,OF MILK: CORRECTION FACTORS AND THE INFLUENCE OF STIRRING: I1 h I11 225 It was originally intended to employ four different amounts of supercooling for each sample of milk, vix. about 1.5, 1.0,0.8, and 0.5" C. It was found, however, that the differences in the readings of the thermometer corresponding to these different amounts of supercooling were in the neighbourhood of 0.002"-an amount so small that the unavoidable errors of observation might possibly approach the same order. It was, therefore, decided to employ only two different amounts of supercooling, as widely apart as practicable, say about 1.5" and 04", and to increase the number of samples examined.It was stated by Hortvet that, unless a much greater amount of supercooling than 0.5" is employed in the use of his cryoscope and technique, the rise of the mercury column is not sufficiently pronounced, and that there is more or less wavering, so that difficulty arises in deciding on the exact point at which the top of the column becomes stationary. Elsdon and Stubbs (Eoc. it.)^ found the same result when using a supercooling of less than about 0.8"; the mercury rose very slowly, and did not maintain a steady position for any appreciable time, and the proper freezing-point might not, under these circumstances, be attained. In the first experiments, made with the object of ascertaining the super- cooling correction, it was observed that where the amount of supercooling was small, that is, less than say 0-75", even in the absence of alcohol in the jacket surrounding the freezing-tube, the rise of temperature, when freezing occurred, was very slow-so slow, indeed, as to suggest doubts whether the thermometer would indicate the freezing-point of the milk, influenced only by supercooling, owing to the reading being affected by the length of time which elapses and the possibility of imperfect thermal insulation, causing a nett loss of heat from the freezing tube and contents.To give an instance; in an experiment when the supercooling was 0-71" the time required for the mercury column to rise until, on observation through the telescope with the aid of the horizontal cross-wire, the ascent became imperceptible, was 92 minutes, as compared with about 3& minutes when the same milk was super- cooled 1-49'.It will be seen later that, in the absence of alcohol in the space surrounding the freezing-tube, the heat insulation of the milk is not perfect; a nett loss of heat occurs, for it is possible t o carry through a freezing-point determination under such conditions. The difference between the two methods of working- with and without alcohol-results in a longer time being required for the cooling of the milk when the space around the freezing-tube is occupied by air. There were also the difficulties of judging when the rising column of mercury had reached the highest point, due to the very slow movement which occurred in that region, and of getting satisfactory readings, owing to the short time that elapsed before a fall took place. The idea of following strictly the Hortvet technique, as regards stirring, for these particular experiments was therefore abandoned. In the first series of experiments, the results of which are recorded in Table 111, four or five stirrings of three strokes each were employed, and in the second series the mechanical stirrer, working at the rate of 40 strokes per minute, was in operation all the time, the thermometer rising until tapping became necessary. It does not appear that these variations in stirring caused any significant differences in the results obtained, but the times of rising of the mercury, after two different extents, large and small,

ISSN:0003-2654    

DOI:10.1039/AN935600032b

出版商:RSC    

年代:1935

数据来源: RSC

摘要:

OF MILK: CORRECTION FACTORS AND THE INFLUENCE OF STIRRING: I1 h I11 225 It was originally intended to employ four different amounts of supercooling for each sample of milk, vix. about 1.5, 1.0,0.8, and 0.5" C. It was found, however, that the differences in the readings of the thermometer corresponding to these different amounts of supercooling were in the neighbourhood of 0.002"-an amount so small that the unavoidable errors of observation might possibly approach the same order. It was, therefore, decided to employ only two different amounts of supercooling, as widely apart as practicable, say about 1.5" and 04", and to increase the number of samples examined. It was stated by Hortvet that, unless a much greater amount of supercooling than 0.5" is employed in the use of his cryoscope and technique, the rise of the mercury column is not sufficiently pronounced, and that there is more or less wavering, so that difficulty arises in deciding on the exact point at which the top of the column becomes stationary. Elsdon and Stubbs (Eoc.it.)^ found the same result when using a supercooling of less than about 0.8"; the mercury rose very slowly, and did not maintain a steady position for any appreciable time, and the proper freezing-point might not, under these circumstances, be attained. In the first experiments, made with the object of ascertaining the super- cooling correction, it was observed that where the amount of supercooling was small, that is, less than say 0-75", even in the absence of alcohol in the jacket surrounding the freezing-tube, the rise of temperature, when freezing occurred, was very slow-so slow, indeed, as to suggest doubts whether the thermometer would indicate the freezing-point of the milk, influenced only by supercooling, owing to the reading being affected by the length of time which elapses and the possibility of imperfect thermal insulation, causing a nett loss of heat from the freezing tube and contents.To give an instance; in an experiment when the supercooling was 0-71" the time required for the mercury column to rise until, on observation through the telescope with the aid of the horizontal cross-wire, the ascent became imperceptible, was 92 minutes, as compared with about 3& minutes when the same milk was super- cooled 1-49'. It will be seen later that, in the absence of alcohol in the space surrounding the freezing-tube, the heat insulation of the milk is not perfect; a nett loss of heat occurs, for it is possible t o carry through a freezing-point determination under such conditions.The difference between the two methods of working- with and without alcohol-results in a longer time being required for the cooling of the milk when the space around the freezing-tube is occupied by air. There were also the difficulties of judging when the rising column of mercury had reached the highest point, due to the very slow movement which occurred in that region, and of getting satisfactory readings, owing to the short time that elapsed before a fall took place. The idea of following strictly the Hortvet technique, as regards stirring, for these particular experiments was therefore abandoned. In the first series of experiments, the results of which are recorded in Table 111, four or five stirrings of three strokes each were employed, and in the second series the mechanical stirrer, working at the rate of 40 strokes per minute, was in operation all the time, the thermometer rising until tapping became necessary. It does not appear that these variations in stirring caused any significant differences in the results obtained, but the times of rising of the mercury, after two different extents, large and small,

ISSN:0003-2654    

DOI:10.1039/AN935600035a

出版商:RSC    

年代:1935

数据来源: RSC

摘要:

WILLIMOTT AN INVESTIGATION OF SOLANINE POISONING 439 DISCUSSION The PRESIDENT remarked that it seemed somewhat strange that potatoes in certain states (old potatoes, green potatoes, etc.) were often described as highly toxic to stock. Many hundreds of tons had been used as stock feed, and he had never actually known of any stock poisoning. Of course, it could be argued that the potatoes used for feeding were often cooked, and much of the solanine dissolved out, but, on the other hand, a large number of these potatoes were used uncooked, and, therefore, stock did consume this vegetable with its full content of solanine, and, so far as he knew, without detriment. During the war a circular was issued, stating that potatoes were an injudicious feed for horses, and setting out the maximum amount that should be given.However, potatoes had been given to horses in limited quantities without bad results. Mr. C. E. SAGE said that cases of solanine poisoning were not infrequent, but he knew of no fatal one, caused by eating the bright red berries of Solanum dulcamara, which grew plentifully in this country. Solanum nzgrum, which had white flowers and black fruits, were sometimes eaten by country children, but he had never met with any casualties. Until recently the fruits of Solanum carolinense were used in America for the preparation of a tincture for medicinal use. I t grew plentifully as a weed in the Southern States, and the orange-coloured fruits were known as Sodom apples. The alkaloids, solanine and solanidine, existed in the fruits, and, as the negroes had used it for a long time as a remedy for falling sickness, the alkaloid could not be particularly toxic, although it was undoubtedly potent. Solanum chenopodium was a native of Queensland, and some thirty years ago he had isolated the alkaloid solanine from it.In Brazil, S. aculeatissimum was the plant yielding Sodom apples. It also contained solanine. With all these sources of solanine, and with potatoes and tomatoes containing it, there seemed to be no great danger from its toxicity. The leaves of S. nigrum were boiled and eaten in the Hawaii Islands, and the fruits known as “fox’s grapes’’ could be eaten in small quantities without any harmful effects. With sprouting potatoes it did not seem beyond the bounds of possibility that some product of decomposition might have caused the illness of people recorded in the paper.Mr. W. PARTRIDGE said that his only experience in the determination of solanine was in connection with a case in which it was alleged that potatoes had been tampered with and had caused illness. He had used the Meyer process, as outlined by Harris and Cockburn (ANALYST, 1918,43, 133) , but with the improve- ments (including the correction for solubility in ammonia wash-water) of Borner and Mattis (ANALYST, 1924, 49, 284). The potatoes in question, substantial areas of which were green, contained 19 mgrms. of solanine per 100 grms. Taking the attitude that normal potatoes contained about 2 mgrms., and never niore than 8 mgrms. per 100 grms., and that 25 mgrms. per 100 grms. were known to be dangerous, he had felt justified in associating the symptoms, minor though they were, with green potatoes.Mr. E. M. HAWXINS remarked that there seemed to be something in the wisdom of old-fashioned country folk. Thirty years ago when, fresh from the town, he went to live in a rural district, the old country folk instructed him that a potato which was allowed to get green through exposure above the earth was likely to be dangerous to human beings and to animals, and he, therefore, never used them. He thought it significant, in the Glasgow case, that more solanine was contained in potatoes which were green from exposure to sunlight than in the white tubers, and the paper certainly bore out this same contention.WILLIMOTT AN INVESTIGATION OF SOLANINE POISONING 439 DISCUSSION The PRESIDENT remarked that it seemed somewhat strange that potatoes in certain states (old potatoes, green potatoes, etc.) were often described as highly toxic to stock.Many hundreds of tons had been used as stock feed, and he had never actually known of any stock poisoning. Of course, it could be argued that the potatoes used for feeding were often cooked, and much of the solanine dissolved out, but, on the other hand, a large number of these potatoes were used uncooked, and, therefore, stock did consume this vegetable with its full content of solanine, and, so far as he knew, without detriment. During the war a circular was issued, stating that potatoes were an injudicious feed for horses, and setting out the maximum amount that should be given.However, potatoes had been given to horses in limited quantities without bad results. Mr. C. E. SAGE said that cases of solanine poisoning were not infrequent, but he knew of no fatal one, caused by eating the bright red berries of Solanum dulcamara, which grew plentifully in this country. Solanum nzgrum, which had white flowers and black fruits, were sometimes eaten by country children, but he had never met with any casualties. Until recently the fruits of Solanum carolinense were used in America for the preparation of a tincture for medicinal use. I t grew plentifully as a weed in the Southern States, and the orange-coloured fruits were known as Sodom apples. The alkaloids, solanine and solanidine, existed in the fruits, and, as the negroes had used it for a long time as a remedy for falling sickness, the alkaloid could not be particularly toxic, although it was undoubtedly potent.Solanum chenopodium was a native of Queensland, and some thirty years ago he had isolated the alkaloid solanine from it. In Brazil, S. aculeatissimum was the plant yielding Sodom apples. It also contained solanine. With all these sources of solanine, and with potatoes and tomatoes containing it, there seemed to be no great danger from its toxicity. The leaves of S. nigrum were boiled and eaten in the Hawaii Islands, and the fruits known as “fox’s grapes’’ could be eaten in small quantities without any harmful effects. With sprouting potatoes it did not seem beyond the bounds of possibility that some product of decomposition might have caused the illness of people recorded in the paper.Mr. W. PARTRIDGE said that his only experience in the determination of solanine was in connection with a case in which it was alleged that potatoes had been tampered with and had caused illness. He had used the Meyer process, as outlined by Harris and Cockburn (ANALYST, 1918,43, 133) , but with the improve- ments (including the correction for solubility in ammonia wash-water) of Borner and Mattis (ANALYST, 1924, 49, 284). The potatoes in question, substantial areas of which were green, contained 19 mgrms. of solanine per 100 grms. Taking the attitude that normal potatoes contained about 2 mgrms., and never niore than 8 mgrms. per 100 grms., and that 25 mgrms. per 100 grms. were known to be dangerous, he had felt justified in associating the symptoms, minor though they were, with green potatoes.Mr. E. M. HAWXINS remarked that there seemed to be something in the wisdom of old-fashioned country folk. Thirty years ago when, fresh from the town, he went to live in a rural district, the old country folk instructed him that a potato which was allowed to get green through exposure above the earth was likely to be dangerous to human beings and to animals, and he, therefore, never used them. He thought it significant, in the Glasgow case, that more solanine was contained in potatoes which were green from exposure to sunlight than in the white tubers, and the paper certainly bore out this same contention.WILLIMOTT AN INVESTIGATION OF SOLANINE POISONING 439 DISCUSSION The PRESIDENT remarked that it seemed somewhat strange that potatoes in certain states (old potatoes, green potatoes, etc.) were often described as highly toxic to stock.Many hundreds of tons had been used as stock feed, and he had never actually known of any stock poisoning. Of course, it could be argued that the potatoes used for feeding were often cooked, and much of the solanine dissolved out, but, on the other hand, a large number of these potatoes were used uncooked, and, therefore, stock did consume this vegetable with its full content of solanine, and, so far as he knew, without detriment. During the war a circular was issued, stating that potatoes were an injudicious feed for horses, and setting out the maximum amount that should be given. However, potatoes had been given to horses in limited quantities without bad results.Mr. C. E. SAGE said that cases of solanine poisoning were not infrequent, but he knew of no fatal one, caused by eating the bright red berries of Solanum dulcamara, which grew plentifully in this country. Solanum nzgrum, which had white flowers and black fruits, were sometimes eaten by country children, but he had never met with any casualties. Until recently the fruits of Solanum carolinense were used in America for the preparation of a tincture for medicinal use. I t grew plentifully as a weed in the Southern States, and the orange-coloured fruits were known as Sodom apples. The alkaloids, solanine and solanidine, existed in the fruits, and, as the negroes had used it for a long time as a remedy for falling sickness, the alkaloid could not be particularly toxic, although it was undoubtedly potent.Solanum chenopodium was a native of Queensland, and some thirty years ago he had isolated the alkaloid solanine from it. In Brazil, S. aculeatissimum was the plant yielding Sodom apples. It also contained solanine. With all these sources of solanine, and with potatoes and tomatoes containing it, there seemed to be no great danger from its toxicity. The leaves of S. nigrum were boiled and eaten in the Hawaii Islands, and the fruits known as “fox’s grapes’’ could be eaten in small quantities without any harmful effects. With sprouting potatoes it did not seem beyond the bounds of possibility that some product of decomposition might have caused the illness of people recorded in the paper.Mr. W. PARTRIDGE said that his only experience in the determination of solanine was in connection with a case in which it was alleged that potatoes had been tampered with and had caused illness. He had used the Meyer process, as outlined by Harris and Cockburn (ANALYST, 1918,43, 133) , but with the improve- ments (including the correction for solubility in ammonia wash-water) of Borner and Mattis (ANALYST, 1924, 49, 284). The potatoes in question, substantial areas of which were green, contained 19 mgrms. of solanine per 100 grms. Taking the attitude that normal potatoes contained about 2 mgrms., and never niore than 8 mgrms. per 100 grms., and that 25 mgrms. per 100 grms. were known to be dangerous, he had felt justified in associating the symptoms, minor though they were, with green potatoes.Mr. E. M. HAWXINS remarked that there seemed to be something in the wisdom of old-fashioned country folk. Thirty years ago when, fresh from the town, he went to live in a rural district, the old country folk instructed him that a potato which was allowed to get green through exposure above the earth was likely to be dangerous to human beings and to animals, and he, therefore, never used them. He thought it significant, in the Glasgow case, that more solanine was contained in potatoes which were green from exposure to sunlight than in the white tubers, and the paper certainly bore out this same contention.WILLIMOTT AN INVESTIGATION OF SOLANINE POISONING 439 DISCUSSION The PRESIDENT remarked that it seemed somewhat strange that potatoes in certain states (old potatoes, green potatoes, etc.) were often described as highly toxic to stock.Many hundreds of tons had been used as stock feed, and he had never actually known of any stock poisoning. Of course, it could be argued that the potatoes used for feeding were often cooked, and much of the solanine dissolved out, but, on the other hand, a large number of these potatoes were used uncooked, and, therefore, stock did consume this vegetable with its full content of solanine, and, so far as he knew, without detriment. During the war a circular was issued, stating that potatoes were an injudicious feed for horses, and setting out the maximum amount that should be given. However, potatoes had been given to horses in limited quantities without bad results.Mr. C. E. SAGE said that cases of solanine poisoning were not infrequent, but he knew of no fatal one, caused by eating the bright red berries of Solanum dulcamara, which grew plentifully in this country. Solanum nzgrum, which had white flowers and black fruits, were sometimes eaten by country children, but he had never met with any casualties. Until recently the fruits of Solanum carolinense were used in America for the preparation of a tincture for medicinal use. I t grew plentifully as a weed in the Southern States, and the orange-coloured fruits were known as Sodom apples. The alkaloids, solanine and solanidine, existed in the fruits, and, as the negroes had used it for a long time as a remedy for falling sickness, the alkaloid could not be particularly toxic, although it was undoubtedly potent.Solanum chenopodium was a native of Queensland, and some thirty years ago he had isolated the alkaloid solanine from it. In Brazil, S. aculeatissimum was the plant yielding Sodom apples. It also contained solanine. With all these sources of solanine, and with potatoes and tomatoes containing it, there seemed to be no great danger from its toxicity. The leaves of S. nigrum were boiled and eaten in the Hawaii Islands, and the fruits known as “fox’s grapes’’ could be eaten in small quantities without any harmful effects. With sprouting potatoes it did not seem beyond the bounds of possibility that some product of decomposition might have caused the illness of people recorded in the paper.Mr. W. PARTRIDGE said that his only experience in the determination of solanine was in connection with a case in which it was alleged that potatoes had been tampered with and had caused illness. He had used the Meyer process, as outlined by Harris and Cockburn (ANALYST, 1918,43, 133) , but with the improve- ments (including the correction for solubility in ammonia wash-water) of Borner and Mattis (ANALYST, 1924, 49, 284). The potatoes in question, substantial areas of which were green, contained 19 mgrms. of solanine per 100 grms. Taking the attitude that normal potatoes contained about 2 mgrms., and never niore than 8 mgrms. per 100 grms., and that 25 mgrms. per 100 grms. were known to be dangerous, he had felt justified in associating the symptoms, minor though they were, with green potatoes. Mr. E. M. HAWXINS remarked that there seemed to be something in the wisdom of old-fashioned country folk. Thirty years ago when, fresh from the town, he went to live in a rural district, the old country folk instructed him that a potato which was allowed to get green through exposure above the earth was likely to be dangerous to human beings and to animals, and he, therefore, never used them. He thought it significant, in the Glasgow case, that more solanine was contained in potatoes which were green from exposure to sunlight than in the white tubers, and the paper certainly bore out this same contention.

ISSN:0003-2654    

DOI:10.1039/AN9356000037

出版商:RSC    

年代:1935

数据来源: RSC

摘要:

WILLIMOTT AN INVESTIGATION OF SOLANINE POISONING 439 DISCUSSION The PRESIDENT remarked that it seemed somewhat strange that potatoes in certain states (old potatoes, green potatoes, etc.) were often described as highly toxic to stock. Many hundreds of tons had been used as stock feed, and he had never actually known of any stock poisoning. Of course, it could be argued that the potatoes used for feeding were often cooked, and much of the solanine dissolved out, but, on the other hand, a large number of these potatoes were used uncooked, and, therefore, stock did consume this vegetable with its full content of solanine, and, so far as he knew, without detriment. During the war a circular was issued, stating that potatoes were an injudicious feed for horses, and setting out the maximum amount that should be given.However, potatoes had been given to horses in limited quantities without bad results. Mr. C. E. SAGE said that cases of solanine poisoning were not infrequent, but he knew of no fatal one, caused by eating the bright red berries of Solanum dulcamara, which grew plentifully in this country. Solanum nzgrum, which had white flowers and black fruits, were sometimes eaten by country children, but he had never met with any casualties. Until recently the fruits of Solanum carolinense were used in America for the preparation of a tincture for medicinal use. I t grew plentifully as a weed in the Southern States, and the orange-coloured fruits were known as Sodom apples. The alkaloids, solanine and solanidine, existed in the fruits, and, as the negroes had used it for a long time as a remedy for falling sickness, the alkaloid could not be particularly toxic, although it was undoubtedly potent. Solanum chenopodium was a native of Queensland, and some thirty years ago he had isolated the alkaloid solanine from it.In Brazil, S. aculeatissimum was the plant yielding Sodom apples. It also contained solanine. With all these sources of solanine, and with potatoes and tomatoes containing it, there seemed to be no great danger from its toxicity. The leaves of S. nigrum were boiled and eaten in the Hawaii Islands, and the fruits known as “fox’s grapes’’ could be eaten in small quantities without any harmful effects. With sprouting potatoes it did not seem beyond the bounds of possibility that some product of decomposition might have caused the illness of people recorded in the paper.Mr. W. PARTRIDGE said that his only experience in the determination of solanine was in connection with a case in which it was alleged that potatoes had been tampered with and had caused illness. He had used the Meyer process, as outlined by Harris and Cockburn (ANALYST, 1918,43, 133) , but with the improve- ments (including the correction for solubility in ammonia wash-water) of Borner and Mattis (ANALYST, 1924, 49, 284). The potatoes in question, substantial areas of which were green, contained 19 mgrms. of solanine per 100 grms. Taking the attitude that normal potatoes contained about 2 mgrms., and never niore than 8 mgrms. per 100 grms., and that 25 mgrms. per 100 grms. were known to be dangerous, he had felt justified in associating the symptoms, minor though they were, with green potatoes.Mr. E. M. HAWXINS remarked that there seemed to be something in the wisdom of old-fashioned country folk. Thirty years ago when, fresh from the town, he went to live in a rural district, the old country folk instructed him that a potato which was allowed to get green through exposure above the earth was likely to be dangerous to human beings and to animals, and he, therefore, never used them. He thought it significant, in the Glasgow case, that more solanine was contained in potatoes which were green from exposure to sunlight than in the white tubers, and the paper certainly bore out this same contention.WILLIMOTT AN INVESTIGATION OF SOLANINE POISONING 439 DISCUSSION The PRESIDENT remarked that it seemed somewhat strange that potatoes in certain states (old potatoes, green potatoes, etc.) were often described as highly toxic to stock.Many hundreds of tons had been used as stock feed, and he had never actually known of any stock poisoning. Of course, it could be argued that the potatoes used for feeding were often cooked, and much of the solanine dissolved out, but, on the other hand, a large number of these potatoes were used uncooked, and, therefore, stock did consume this vegetable with its full content of solanine, and, so far as he knew, without detriment. During the war a circular was issued, stating that potatoes were an injudicious feed for horses, and setting out the maximum amount that should be given.However, potatoes had been given to horses in limited quantities without bad results. Mr. C. E. SAGE said that cases of solanine poisoning were not infrequent, but he knew of no fatal one, caused by eating the bright red berries of Solanum dulcamara, which grew plentifully in this country. Solanum nzgrum, which had white flowers and black fruits, were sometimes eaten by country children, but he had never met with any casualties. Until recently the fruits of Solanum carolinense were used in America for the preparation of a tincture for medicinal use. I t grew plentifully as a weed in the Southern States, and the orange-coloured fruits were known as Sodom apples. The alkaloids, solanine and solanidine, existed in the fruits, and, as the negroes had used it for a long time as a remedy for falling sickness, the alkaloid could not be particularly toxic, although it was undoubtedly potent.Solanum chenopodium was a native of Queensland, and some thirty years ago he had isolated the alkaloid solanine from it. In Brazil, S. aculeatissimum was the plant yielding Sodom apples. It also contained solanine. With all these sources of solanine, and with potatoes and tomatoes containing it, there seemed to be no great danger from its toxicity. The leaves of S. nigrum were boiled and eaten in the Hawaii Islands, and the fruits known as “fox’s grapes’’ could be eaten in small quantities without any harmful effects. With sprouting potatoes it did not seem beyond the bounds of possibility that some product of decomposition might have caused the illness of people recorded in the paper.Mr. W. PARTRIDGE said that his only experience in the determination of solanine was in connection with a case in which it was alleged that potatoes had been tampered with and had caused illness. He had used the Meyer process, as outlined by Harris and Cockburn (ANALYST, 1918,43, 133) , but with the improve- ments (including the correction for solubility in ammonia wash-water) of Borner and Mattis (ANALYST, 1924, 49, 284). The potatoes in question, substantial areas of which were green, contained 19 mgrms. of solanine per 100 grms. Taking the attitude that normal potatoes contained about 2 mgrms., and never niore than 8 mgrms. per 100 grms., and that 25 mgrms. per 100 grms. were known to be dangerous, he had felt justified in associating the symptoms, minor though they were, with green potatoes.Mr. E. M. HAWXINS remarked that there seemed to be something in the wisdom of old-fashioned country folk. Thirty years ago when, fresh from the town, he went to live in a rural district, the old country folk instructed him that a potato which was allowed to get green through exposure above the earth was likely to be dangerous to human beings and to animals, and he, therefore, never used them. He thought it significant, in the Glasgow case, that more solanine was contained in potatoes which were green from exposure to sunlight than in the white tubers, and the paper certainly bore out this same contention.WILLIMOTT AN INVESTIGATION OF SOLANINE POISONING 439 DISCUSSION The PRESIDENT remarked that it seemed somewhat strange that potatoes in certain states (old potatoes, green potatoes, etc.) were often described as highly toxic to stock.Many hundreds of tons had been used as stock feed, and he had never actually known of any stock poisoning. Of course, it could be argued that the potatoes used for feeding were often cooked, and much of the solanine dissolved out, but, on the other hand, a large number of these potatoes were used uncooked, and, therefore, stock did consume this vegetable with its full content of solanine, and, so far as he knew, without detriment. During the war a circular was issued, stating that potatoes were an injudicious feed for horses, and setting out the maximum amount that should be given. However, potatoes had been given to horses in limited quantities without bad results.Mr. C. E. SAGE said that cases of solanine poisoning were not infrequent, but he knew of no fatal one, caused by eating the bright red berries of Solanum dulcamara, which grew plentifully in this country. Solanum nzgrum, which had white flowers and black fruits, were sometimes eaten by country children, but he had never met with any casualties. Until recently the fruits of Solanum carolinense were used in America for the preparation of a tincture for medicinal use. I t grew plentifully as a weed in the Southern States, and the orange-coloured fruits were known as Sodom apples. The alkaloids, solanine and solanidine, existed in the fruits, and, as the negroes had used it for a long time as a remedy for falling sickness, the alkaloid could not be particularly toxic, although it was undoubtedly potent.Solanum chenopodium was a native of Queensland, and some thirty years ago he had isolated the alkaloid solanine from it. In Brazil, S. aculeatissimum was the plant yielding Sodom apples. It also contained solanine. With all these sources of solanine, and with potatoes and tomatoes containing it, there seemed to be no great danger from its toxicity. The leaves of S. nigrum were boiled and eaten in the Hawaii Islands, and the fruits known as “fox’s grapes’’ could be eaten in small quantities without any harmful effects. With sprouting potatoes it did not seem beyond the bounds of possibility that some product of decomposition might have caused the illness of people recorded in the paper.Mr. W. PARTRIDGE said that his only experience in the determination of solanine was in connection with a case in which it was alleged that potatoes had been tampered with and had caused illness. He had used the Meyer process, as outlined by Harris and Cockburn (ANALYST, 1918,43, 133) , but with the improve- ments (including the correction for solubility in ammonia wash-water) of Borner and Mattis (ANALYST, 1924, 49, 284). The potatoes in question, substantial areas of which were green, contained 19 mgrms. of solanine per 100 grms. Taking the attitude that normal potatoes contained about 2 mgrms., and never niore than 8 mgrms. per 100 grms., and that 25 mgrms. per 100 grms. were known to be dangerous, he had felt justified in associating the symptoms, minor though they were, with green potatoes. Mr. E. M. HAWXINS remarked that there seemed to be something in the wisdom of old-fashioned country folk. Thirty years ago when, fresh from the town, he went to live in a rural district, the old country folk instructed him that a potato which was allowed to get green through exposure above the earth was likely to be dangerous to human beings and to animals, and he, therefore, never used them. He thought it significant, in the Glasgow case, that more solanine was contained in potatoes which were green from exposure to sunlight than in the white tubers, and the paper certainly bore out this same contention.

ISSN:0003-2654    

DOI:10.1039/AN9356000040

出版商:RSC    

年代:1935

数据来源: RSC

摘要:

WILLIMOTT AN INVESTIGATION OF SOLANINE POISONING 439 DISCUSSION The PRESIDENT remarked that it seemed somewhat strange that potatoes in certain states (old potatoes, green potatoes, etc.) were often described as highly toxic to stock. Many hundreds of tons had been used as stock feed, and he had never actually known of any stock poisoning. Of course, it could be argued that the potatoes used for feeding were often cooked, and much of the solanine dissolved out, but, on the other hand, a large number of these potatoes were used uncooked, and, therefore, stock did consume this vegetable with its full content of solanine, and, so far as he knew, without detriment. During the war a circular was issued, stating that potatoes were an injudicious feed for horses, and setting out the maximum amount that should be given.However, potatoes had been given to horses in limited quantities without bad results. Mr. C. E. SAGE said that cases of solanine poisoning were not infrequent, but he knew of no fatal one, caused by eating the bright red berries of Solanum dulcamara, which grew plentifully in this country. Solanum nzgrum, which had white flowers and black fruits, were sometimes eaten by country children, but he had never met with any casualties. Until recently the fruits of Solanum carolinense were used in America for the preparation of a tincture for medicinal use. I t grew plentifully as a weed in the Southern States, and the orange-coloured fruits were known as Sodom apples. The alkaloids, solanine and solanidine, existed in the fruits, and, as the negroes had used it for a long time as a remedy for falling sickness, the alkaloid could not be particularly toxic, although it was undoubtedly potent. Solanum chenopodium was a native of Queensland, and some thirty years ago he had isolated the alkaloid solanine from it.In Brazil, S. aculeatissimum was the plant yielding Sodom apples. It also contained solanine. With all these sources of solanine, and with potatoes and tomatoes containing it, there seemed to be no great danger from its toxicity. The leaves of S. nigrum were boiled and eaten in the Hawaii Islands, and the fruits known as “fox’s grapes’’ could be eaten in small quantities without any harmful effects. With sprouting potatoes it did not seem beyond the bounds of possibility that some product of decomposition might have caused the illness of people recorded in the paper.Mr. W. PARTRIDGE said that his only experience in the determination of solanine was in connection with a case in which it was alleged that potatoes had been tampered with and had caused illness. He had used the Meyer process, as outlined by Harris and Cockburn (ANALYST, 1918,43, 133) , but with the improve- ments (including the correction for solubility in ammonia wash-water) of Borner and Mattis (ANALYST, 1924, 49, 284). The potatoes in question, substantial areas of which were green, contained 19 mgrms. of solanine per 100 grms. Taking the attitude that normal potatoes contained about 2 mgrms., and never niore than 8 mgrms. per 100 grms., and that 25 mgrms. per 100 grms. were known to be dangerous, he had felt justified in associating the symptoms, minor though they were, with green potatoes.Mr. E. M. HAWXINS remarked that there seemed to be something in the wisdom of old-fashioned country folk. Thirty years ago when, fresh from the town, he went to live in a rural district, the old country folk instructed him that a potato which was allowed to get green through exposure above the earth was likely to be dangerous to human beings and to animals, and he, therefore, never used them. He thought it significant, in the Glasgow case, that more solanine was contained in potatoes which were green from exposure to sunlight than in the white tubers, and the paper certainly bore out this same contention.WILLIMOTT AN INVESTIGATION OF SOLANINE POISONING 439 DISCUSSION The PRESIDENT remarked that it seemed somewhat strange that potatoes in certain states (old potatoes, green potatoes, etc.) were often described as highly toxic to stock.Many hundreds of tons had been used as stock feed, and he had never actually known of any stock poisoning. Of course, it could be argued that the potatoes used for feeding were often cooked, and much of the solanine dissolved out, but, on the other hand, a large number of these potatoes were used uncooked, and, therefore, stock did consume this vegetable with its full content of solanine, and, so far as he knew, without detriment. During the war a circular was issued, stating that potatoes were an injudicious feed for horses, and setting out the maximum amount that should be given.However, potatoes had been given to horses in limited quantities without bad results. Mr. C. E. SAGE said that cases of solanine poisoning were not infrequent, but he knew of no fatal one, caused by eating the bright red berries of Solanum dulcamara, which grew plentifully in this country. Solanum nzgrum, which had white flowers and black fruits, were sometimes eaten by country children, but he had never met with any casualties. Until recently the fruits of Solanum carolinense were used in America for the preparation of a tincture for medicinal use. I t grew plentifully as a weed in the Southern States, and the orange-coloured fruits were known as Sodom apples. The alkaloids, solanine and solanidine, existed in the fruits, and, as the negroes had used it for a long time as a remedy for falling sickness, the alkaloid could not be particularly toxic, although it was undoubtedly potent.Solanum chenopodium was a native of Queensland, and some thirty years ago he had isolated the alkaloid solanine from it. In Brazil, S. aculeatissimum was the plant yielding Sodom apples. It also contained solanine. With all these sources of solanine, and with potatoes and tomatoes containing it, there seemed to be no great danger from its toxicity. The leaves of S. nigrum were boiled and eaten in the Hawaii Islands, and the fruits known as “fox’s grapes’’ could be eaten in small quantities without any harmful effects. With sprouting potatoes it did not seem beyond the bounds of possibility that some product of decomposition might have caused the illness of people recorded in the paper.Mr. W. PARTRIDGE said that his only experience in the determination of solanine was in connection with a case in which it was alleged that potatoes had been tampered with and had caused illness. He had used the Meyer process, as outlined by Harris and Cockburn (ANALYST, 1918,43, 133) , but with the improve- ments (including the correction for solubility in ammonia wash-water) of Borner and Mattis (ANALYST, 1924, 49, 284). The potatoes in question, substantial areas of which were green, contained 19 mgrms. of solanine per 100 grms. Taking the attitude that normal potatoes contained about 2 mgrms., and never niore than 8 mgrms. per 100 grms., and that 25 mgrms. per 100 grms. were known to be dangerous, he had felt justified in associating the symptoms, minor though they were, with green potatoes. Mr. E. M. HAWXINS remarked that there seemed to be something in the wisdom of old-fashioned country folk. Thirty years ago when, fresh from the town, he went to live in a rural district, the old country folk instructed him that a potato which was allowed to get green through exposure above the earth was likely to be dangerous to human beings and to animals, and he, therefore, never used them. He thought it significant, in the Glasgow case, that more solanine was contained in potatoes which were green from exposure to sunlight than in the white tubers, and the paper certainly bore out this same contention.

ISSN:0003-2654    

DOI:10.1039/AN9356000042

出版商:RSC    

年代:1935

数据来源: RSC

摘要:

WILLIMOTT AN INVESTIGATION OF SOLANINE POISONING 439 DISCUSSION The PRESIDENT remarked that it seemed somewhat strange that potatoes in certain states (old potatoes, green potatoes, etc.) were often described as highly toxic to stock. Many hundreds of tons had been used as stock feed, and he had never actually known of any stock poisoning. Of course, it could be argued that the potatoes used for feeding were often cooked, and much of the solanine dissolved out, but, on the other hand, a large number of these potatoes were used uncooked, and, therefore, stock did consume this vegetable with its full content of solanine, and, so far as he knew, without detriment. During the war a circular was issued, stating that potatoes were an injudicious feed for horses, and setting out the maximum amount that should be given.However, potatoes had been given to horses in limited quantities without bad results. Mr. C. E. SAGE said that cases of solanine poisoning were not infrequent, but he knew of no fatal one, caused by eating the bright red berries of Solanum dulcamara, which grew plentifully in this country. Solanum nzgrum, which had white flowers and black fruits, were sometimes eaten by country children, but he had never met with any casualties. Until recently the fruits of Solanum carolinense were used in America for the preparation of a tincture for medicinal use. I t grew plentifully as a weed in the Southern States, and the orange-coloured fruits were known as Sodom apples. The alkaloids, solanine and solanidine, existed in the fruits, and, as the negroes had used it for a long time as a remedy for falling sickness, the alkaloid could not be particularly toxic, although it was undoubtedly potent. Solanum chenopodium was a native of Queensland, and some thirty years ago he had isolated the alkaloid solanine from it.In Brazil, S. aculeatissimum was the plant yielding Sodom apples. It also contained solanine. With all these sources of solanine, and with potatoes and tomatoes containing it, there seemed to be no great danger from its toxicity. The leaves of S. nigrum were boiled and eaten in the Hawaii Islands, and the fruits known as “fox’s grapes’’ could be eaten in small quantities without any harmful effects. With sprouting potatoes it did not seem beyond the bounds of possibility that some product of decomposition might have caused the illness of people recorded in the paper.Mr. W. PARTRIDGE said that his only experience in the determination of solanine was in connection with a case in which it was alleged that potatoes had been tampered with and had caused illness. He had used the Meyer process, as outlined by Harris and Cockburn (ANALYST, 1918,43, 133) , but with the improve- ments (including the correction for solubility in ammonia wash-water) of Borner and Mattis (ANALYST, 1924, 49, 284). The potatoes in question, substantial areas of which were green, contained 19 mgrms. of solanine per 100 grms. Taking the attitude that normal potatoes contained about 2 mgrms., and never niore than 8 mgrms. per 100 grms., and that 25 mgrms. per 100 grms. were known to be dangerous, he had felt justified in associating the symptoms, minor though they were, with green potatoes.Mr. E. M. HAWXINS remarked that there seemed to be something in the wisdom of old-fashioned country folk. Thirty years ago when, fresh from the town, he went to live in a rural district, the old country folk instructed him that a potato which was allowed to get green through exposure above the earth was likely to be dangerous to human beings and to animals, and he, therefore, never used them. He thought it significant, in the Glasgow case, that more solanine was contained in potatoes which were green from exposure to sunlight than in the white tubers, and the paper certainly bore out this same contention.WILLIMOTT AN INVESTIGATION OF SOLANINE POISONING 439 DISCUSSION The PRESIDENT remarked that it seemed somewhat strange that potatoes in certain states (old potatoes, green potatoes, etc.) were often described as highly toxic to stock.Many hundreds of tons had been used as stock feed, and he had never actually known of any stock poisoning. Of course, it could be argued that the potatoes used for feeding were often cooked, and much of the solanine dissolved out, but, on the other hand, a large number of these potatoes were used uncooked, and, therefore, stock did consume this vegetable with its full content of solanine, and, so far as he knew, without detriment. During the war a circular was issued, stating that potatoes were an injudicious feed for horses, and setting out the maximum amount that should be given.However, potatoes had been given to horses in limited quantities without bad results. Mr. C. E. SAGE said that cases of solanine poisoning were not infrequent, but he knew of no fatal one, caused by eating the bright red berries of Solanum dulcamara, which grew plentifully in this country. Solanum nzgrum, which had white flowers and black fruits, were sometimes eaten by country children, but he had never met with any casualties. Until recently the fruits of Solanum carolinense were used in America for the preparation of a tincture for medicinal use. I t grew plentifully as a weed in the Southern States, and the orange-coloured fruits were known as Sodom apples. The alkaloids, solanine and solanidine, existed in the fruits, and, as the negroes had used it for a long time as a remedy for falling sickness, the alkaloid could not be particularly toxic, although it was undoubtedly potent.Solanum chenopodium was a native of Queensland, and some thirty years ago he had isolated the alkaloid solanine from it. In Brazil, S. aculeatissimum was the plant yielding Sodom apples. It also contained solanine. With all these sources of solanine, and with potatoes and tomatoes containing it, there seemed to be no great danger from its toxicity. The leaves of S. nigrum were boiled and eaten in the Hawaii Islands, and the fruits known as “fox’s grapes’’ could be eaten in small quantities without any harmful effects. With sprouting potatoes it did not seem beyond the bounds of possibility that some product of decomposition might have caused the illness of people recorded in the paper.Mr. W. PARTRIDGE said that his only experience in the determination of solanine was in connection with a case in which it was alleged that potatoes had been tampered with and had caused illness. He had used the Meyer process, as outlined by Harris and Cockburn (ANALYST, 1918,43, 133) , but with the improve- ments (including the correction for solubility in ammonia wash-water) of Borner and Mattis (ANALYST, 1924, 49, 284). The potatoes in question, substantial areas of which were green, contained 19 mgrms. of solanine per 100 grms. Taking the attitude that normal potatoes contained about 2 mgrms., and never niore than 8 mgrms. per 100 grms., and that 25 mgrms. per 100 grms. were known to be dangerous, he had felt justified in associating the symptoms, minor though they were, with green potatoes. Mr. E. M. HAWXINS remarked that there seemed to be something in the wisdom of old-fashioned country folk. Thirty years ago when, fresh from the town, he went to live in a rural district, the old country folk instructed him that a potato which was allowed to get green through exposure above the earth was likely to be dangerous to human beings and to animals, and he, therefore, never used them. He thought it significant, in the Glasgow case, that more solanine was contained in potatoes which were green from exposure to sunlight than in the white tubers, and the paper certainly bore out this same contention.

ISSN:0003-2654    

DOI:10.1039/AN9356000043

出版商:RSC    

年代:1935

数据来源: RSC