摘要:

May, 19661 SHORT PAPERS 335 Removal of Polyphenolic Compounds Interfering with Carbohydrate Determinations in Plant Extracts with an Insoluble Polyphenol Adsorbent BY G. W. SANDERSON AND B. P. M. PEREKA (Tea Research Institute of Ceyloe, Talawakelle, Ceylon) IT has long been recogiiised that catechins give most of the reactions characteristic of carbo- hydrates1 Further, it has been reported that clarification of plant extracts with lead acetate2 is not sufficient to remove all the catechins and related polyphenolic compounds contained in extracts of plant tissues which contain high concentrations of these compo~nds.~ 9 4 During the course of our recent investigations of carbohydrates in tea plants5 we have confirmed the fact that catechins and related compounds interfere in the quantitative determination of carbohydrates, and that clarification of extracts of tea-plant tissues with neutral lead acetate2 is not effective in reducing this interference to negligible amounts.We have devised a rapid and effective method for removing interfering catechins and related polyphenolic compounds from plant-tissue extracts which is based on the polyphenol absorbing properties of Polyclar L4'1',c an insoluble cross-linked poly(viny1 pyrrolidone) manufactured by Antara Chemicals Division of General Aniline & Film Corp., New York, N.Y., U.S.A. The method as applicable to tea shoot tips is described as follows. Extract the plant material with 80 per cent. (v/v) ethanol and clarify with neutral lead acetate in the usual way.2 The clarified extract is made up t o volume and 1 g of Polyclar AT per g of dry weight tissue is added.The mixture is stirred for 30 minutes, after which the Polyclar AT and adsorbed polyphenolic compounds are removed by centrifugation. Re-treatment of the extracts is made with 0.2 g of Polyclar AT per g of dry weight tissue in the same manner as previously indicated. Carbohydrates are deter- mined in the Polyclar AT treated extracts by any convenient method (we use the method of Somogyi'). The quantitative nature of the interference caused by catechins in the determination of carbohydrates and the effectiveness of Polyclar AT treatment in removing this interference is shown in Table I. Further, these results show that the Polyclar A?' treatment does not interfere with the determination of the carbohydrates themselves.TABLE I THE QUANTITATIVE NATURE OF CATECHIN INTERFERENCE IN THE DETERMINATION OF CARBOHYDRATES, AND THE REMOVAL O F THIS INTERFERENCE JIr'ITH POLVCLAR AT TREATMENT Carbohydrates were determined by the method of Somogyi.' Polyclar treatment was made by stirring 5.0 g of Polyclar AT per 100 mg of sugar (or catechin) in the solution being tested for 30 minutes Ti tre before Polyclar Titre after Polyclar Significance of change treatment treatment in titre due to Polyrlar II'eight of chemical compound (ml of 0.05 N thiosulphate) treatment Glucose, 135 pg . . . . (;lLlcose, 250 pg . . . . . . D-Catcchin, 100 pg . . . . D-Catechin, 200 pg . . . . Glucose, 125 pg + n-Catechin, 100 pg . . Ribose, 200 pg . . . . . . Fructose, 250 pg .. . . Sucrose, hpdrolysed, 500 pg . . 0.94 1-93 0.36 0-73 1.28 0.98 1.90 3-81 0.02" 0-987 0.98 1-85 3.74 * Not significantly different from zero. 7 Not significantly different from titre for glucose only. none none significant change significant change (,p <: 0.01) (p < 0.01) (p < 0.01) significant change none none none The inadequacy of the usual lead acetate clarification procedure2 for removing the catechins, and related polyphenolic compounds present in three different plant tissues is shown in Table 11.336 SHORT PAPERS [,.Z?zalyst, Vol. 91 The results also show that Polyclar AT treatment was effective in each case in removing these interfering compounds, and this was further verified by examination of the various fractions by using paper chromatography.8 TABLE I1 EFFECT OF POLYCLrZR TREATMENT ON THE CATECHIS AND THE “APPARENT” CARBOHYDRATE CONTENTS O F LL4U ACETATE CLARIFIED HTi EXTRACTS OF THREE PLANT TISSUES Carbohydrates were determined by the method of So~nogyi.~ Catechins were determined by the concentrated sulphuric acid - vanillin method of Swain and Hillis.lo Tea (Camellin si?zeizsis, L.) II\sh plantain r~~ -2.- 7 (.lIiisapavadisiaca, L.) Shoot tips Roots fruit --L- 7 r d - 7 TpA- 7 Carbo- Carbo- Carbo- Treat men t Catcchins hydrates Catechins hydrates Catechins hydrates (mg per g of dry weight tissue) - - Extract, 80 per cent., v/v .. . . 240 34 10.6 - After clarification with neutral lead After first Polyclar treatment After second Polyclar treatment After third Polyclar treatment acetate2 .. . . . . . . 15.7 17.1 2.86 2.35 0.50 8.33 (1.0 g per g of dry weight tissue) . . 0-23 5.66 0.00 1.49 0.00 6-44 (0.2 g per g of dry weight tissue) . . 0.00 5.09 0.00 3-54 0.00 6.33 (0.2 g per g of dry weight tissue) . 0.00 6.00 - - - - The method dcscribed in this paper is especially important in tea biochemistry because of the high concentration of catechins and related polyphenolic compounds present in these tissue^,^ but, as shown by our work on ash plantain fruit, the method may also be applied with advantage in carbohydrate studies on other plant tissues. We thank Mr. P. Kanapathipillai for assistance with the statistical analysis o f our results. 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. KEFE ium CES Shaw, W. S., “Theotannin. I. Theotannin in Relation to Green Leaf,” Second Edition, United Planters Association, South India, Madras, 1935, p. 2. Horwitz, W., Editov, “Official Methods of Analysis of the Association of Official Agricultural Chemists,” Xinth Edition, Association of Official Agricultural Chemists, II’ashington, D.C., 1959, p. 421. Kuntzel, A., and Melzer, E., J , Amev. Leath. Chem. .4ss., 1948, 43, 613. Cartwright, R. A . , and Roberts, E. -4. H., J . Sci. Fd Agric., 1954, 5 , 600. Sanderson, G. W., and Perera, B. P. JI., Tea Q., 1965, 36, 6. RTcFarlane, W. D., and Bayne, P. D., European Bvewei~>~ Conveiitioii, 1961, p. 278. Soniogyi, M., J . Riol. Chem., 1945, 160, 61. Roberts, E. A. H., i n Geissman, T. A . , Editor, “The Chemistry of Flax-onoid Compounds,” Pergamon Press Ltd., T,ondon, 1962, p. 468. Vuataz, L., Brandenberger, H., and Egli, R. H., .J. Chvomat., 1959, 2, 173. Swain, T., and Hillis, W. G., J . Sci. Fd Agric., 1959, 10, 63. Received d itgirst 8th, 1965

ISSN:0003-2654    

DOI:10.1039/AN9669100335

出版商:RSC    

年代:1966

数据来源: RSC

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336 SHORT PAPERS [,.Z?zalyst, Vol. 91 The Detection of Dinitro and Trinitro Aromatic Bodies in Industrial Blasting Explosives BY S. A. H. AMAS AND H. J . YALLOP (Royal Armament Research and Development Establishment, Fort Halstead, Kent) THE detection and identification of nitro-bodies is a common requirement in the explosives labora- tory. Janowski’s reactionf provides an adequate test for dinitro and trinitro aromatic compounds by means of the characteristic colours developed in alkaline acetone. In the forensic laboratory, however, these compounds normally have to be detected as minor constituents in small samplesMay, 19661 SHORT PAPERS 337 of industrial blasting explosives. For this purpose J anowski’s reaction has been found unsatis- factory, particularly when applied as a spot test.The reason for this is that the test is insufficiently sensitive, and so an attempt has been made to effect a n improvement. It has been found that this gives better results with forensic samples than any other of a range of organic solvents tested. The alkali normally used for this reaction is potassium hydroxide, 5 per cent. being the commonly recommended strength. It was found, however, that the sensitivity of the test was increased if stronger alkali was used. This agrees with the observations made by English on alcoholic sodium hydroxide. The limit of detection for 2,4-dinitrotoluene was found t o be 20 pg with 10 per cent. potassium hydroxide, improving to 1 p g with 50 per cent. potassium hydroxide. Because very strong alkali is not a convenient reagent for bench use, alternatives were con- sidered.It was known that coloured complexes are formed between some nitrobodies and organic bases,3 and this reaction forms a convenient technique for colouring trinitrotoluene in crystal struc- ture investigation^.^ A range of organic bases was therefore studied, and three emerged as giving good colour reactions with di- and trinitrotoluene a t low concentrations. These were tetramethyl- ammonium hydroxide, diethylene triamine and tetraethylene pentamine. For use as a bench reagent, 25 per cent. aqueous tetramethylammonium hydroxide was found to be the most con- venient since it is a clear mobile liquid that can be used satisfactorily with a dropping bottle. The reaction can be readily carried out on a spot plate. The addition of a 5 to 10-mg specimen of one drop of acetone - alcohol, and one drop of tetramethylammonium hydroxide produces a blue colour with dinitrotoluene and a dark red with trinitrotoluene.The initial colour should be observed since changes occur with time. A slight yellow is produced with nitroglycerine so that if this is present thc colour produced with dinitrotoluene is green. The test has been applied to a wide range of obsolete and current industrial blasting explosives, and i t has been found that none of the other components present interfere with the reaction. The limits of identification are 4 p g for nz-dinitrobenzene, 2 pg for 2,4-dinitrotoluene and 1 pg for 2,4,6-trinitrotoluene. English2 has described the use of 50/50 acetone - alcohol as a solvent. REFERENCES 1. 2. 3. 4. Janowski, J. V., Ber., 1886, 19, 2155. English, F. L., Analyt. Chem., 1948, 20, 745. Davis, T. L., “The Chemistry of Powder and Explosives,” John Vc’ilcy and Sons Inc., Sew \*ark, Yallop, H. J., Analyst, 1960, 85, 300. 1941, Volume 1, p. 135. Received August 17th, 1965

ISSN:0003-2654    

DOI:10.1039/AN9669100336

出版商:RSC    

年代:1966

数据来源: RSC

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May, 19661 SHORT PAPERS 337 The Use of Molecular Sieve 5A for Collecting Fractions from a Gas Chromatograph BY M. CA4RTWHIGHT AXD ,4. HEYWOOD (Imperial Clzetnical litdustvies Ltd., Dyestuffs Division, Hexagon House, Blacklejj, Manchestev 9) THE separation of the components of a mixture by gas chromatography, and examination of the appropriate fractions in a mass spectrometer is now recognised as one of the most useful way5 of identifying the unknown compounds revealed on a gas-chromatographic record. In the most convenient procedure, the chromatograph column is attached directly to the inlet manifold oi the mass spectrometer, into which the fractions are fed in turn, so that the mass spectrum is obtained without isolation of the unknown components ; however, all the components emerging from the column are diluted with carrier gas, and when a compound is present in very small amounts, i.e., as a trace impurity in the sample, the direct gas - liquid chromatography - mass spectrometer apparatus gives rather weak spectra, making identification more difficult.In order to obtain stronger spectra it is desirable to remove the excess of carrier gas, and although with hydrogen and helium this can be done by fractional diffusion through a fritted-glass tube,l or by the device described by Ryhage,2 an alternative and simpler procedure is available whereby the component is trapped on an adsorbent and subsequently desorbed (by heating) into the mass spectrometer. Silica gel has been used for this p ~ r p o s e , ~ * ~ but we have found that this converts alcohols into olefins, and irreversibly adsorbs amines.We find that molecular sieve 5A is a xrery338 BOOK REVIEWS [Awalyst, Vol. 91 useful adsorbent as it is free from these disadvantages. L-nder the conditions given below, the molecular sieve is not only a strong adsorbent for substances with short straight chain molecules, but is also a weak adsorbent for all types of substances with more complex molecules. The molecular sieve is ground, and the 30 to 60-mesh fraction is heated in zwczto to 360” C im- mediately before use; 0.1 g of this material is loosely packed (and held in position by quartz-wool plugs) in glass tubes 8 cm long, a 3-mm bore drawn out a t one end. A number of these adsorption tubes are prepared and held ready for use during the chromatographic run.For the initial separation a packed analytical-scale gas - liquid chromatography column is used with a load of sample of about 1 mg, but the load can be increased when necessary, provided that the resolution of the required components is not too greatly impaired. A narrow bore T-piece is inserted between the chromatograph column and the flame ionisation detector so that about half the effluent passes to the detector and about half to the side pipe; when an unknown component of a sample begins to emerge from the column (as indicated by the beginning of a peak on the chromatograph chart), the narrow end of an adsorption tube is connected to this side pipe by silicone tubing, and this adsorption tube is removed when the component has been completely eluted. In this lvap a number of components can be collected from one chromatographic run; the adsorption tubes are then placed in sealed containers until they can be analysed on the mass spectrometer.For examination in the mass spectrometer, the molecular sieve packing is transferred from the adsorption tube into a 2 x :-inch glass tube (closed a t one end), which is then connected by means of a vacuum-tight joint to the inlet manifold of the mass spectrometer. The tube is evacuated (after cooling with crushed solid carbon dioxide if the compounds under investigation are very volatile), opened to the mass spectrometer, and heated with a small luminous bunsen flame until a satisfactory pressure or monitor reading (depending on the type of mass spectrometer used) is obtained; care is taken not to heat the tube too strongly, otherwise i t may collapse. The tube is isolated from the mass spectrometer by closing the appropriate tap while the mass spectrum is being recorded, to prevent re-adsorption on the molecular sieve.This procedure has given spectra a t least fifty times as strong as those obtained from the direct gas - liquid chromatography mass spectrometer apparatus. AIolecular sieve 5-4 has also been used successfully for adsorbing organic vapour from the atmos- phere, for which purpose i t has an advantage over the more usual gas - liquid chromatography5 pacliings because it allows one to sample much larger volumes of air before “break-through” of the organic compound occurs. 1. Biemann, I<., A~.zaZyt. Chenz., 1964, 16, 1135. 2. Ryhage, R., Ibzd., 1964, 36, 759. 3. Drew, C. PI., and Johnson, J . H., J. Chvoinai., 1962, 9, 264. 1. Widmark, I<., and \Vidmark, G., A d a Chum. Scand., 1962, 16, 675. 5. Cropper, F. R., and Kaminslry, S., AnaZyt. Chew., 1963, 35, 735. Received Octobev loth, 1965

ISSN:0003-2654    

DOI:10.1039/AN9669100337

出版商:RSC    

年代:1966

数据来源: RSC

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338 BOOK REVIEWS [Awalyst, Vol. 91 Book Reviews NE.:\VER 1 2 ~ n o s TITRANTS. By A. HHRKA, J . VL-LTERIS and J . Z~’KX. Translatcd by H. \YEISZ. Pp. x + 215. Oxford, I,ondon, Edinburgh, New York, Paris and Frankfurt : Pergamon Press. 1965. Price 60s. This is a translation, with a certain amount of revision, of the German edition of 1964 prepared trom the original Czech edition of 1961. It deals succinctly but compendiously with the titrants alkaline permanganate (10 pp), manganese(rrI), copper(II), hexacyanoferrate(m), hypochlorite, hypobromite, chloraniine-T ( 1 1 pp), bromine, N-bromosuccinimide, iodine monochloride ( 1 1 pp), periodate, lead(Iv), vanadium(v) ( 1 1 pp), iron(m), cobalt(rrr), hydrogen peroxide, chromium(I1) (16 pp), tin(rI), arsenic(III), mercury(r), copper(I), molybdenum(v), molybdenum(IrI), tungsten(v), tungsten(III), uranium(Iv), vanadium(rr), vanadium(Iv), ascorbic acid ( 1 1 pp), hydroquinone, hydrazine, nitrite and certain others.The longest chapters are indicated by the number of pages they occupy: the remaining chapters are quite short. Although in line of succession with older t e s t s , this book has not the explanatory discussion of Bottger’s “Neuer Methoden der Massanalyse, ” i,or the critical appraisal and cletail of Kolthoff and Belcher’s “Volumetric Analysis,” Volume 111.May, 19661 BOOK REVIEWS 339 Such depth of treatment is not to be expected for reagents of recent vintage, and need not be repeated if there is nothing to add to the information in the older texts on longer established titrants. Each chapter opens with a brief, indeed exiguous, introduction outlining the principles of the reactions of the reagent.This is followed by an account of the preparation and standardisation of solutions and some account of visual indicators that have been used with the reagent. The main part of each chapter is a review of the determinations that have been made with the reagent with a brief indication of working conditions. Finally, a bibliography is included covering the literature satisfactorily and fairly comprehensively up to 1962 or 1963. The introduction often amounts to no more than a simple statement, and is sometimes a t fault. No account is taken of rates of reaction, nor of reaction mechanisms in the true scnse. The survey of methods gives barelj- sufficient working detail and is uncritical.The most \valuable feature of the book is the extensive bibliographies which the surveys of methods serve to annotate. The treatment will appeal to the analyst rather than to the analytical chemist, and mill serve to bring to his attention many alternatii-e or new methods of determination which may help to solve his particular problemi. The real virtue of this book is that it offers a compact and compendious key to the literature of the less familiar electron-transfer titrimetric reagents. Tn this respect it will find a ready welcome from all engaged in this field. COVPTJTER PROGRAMMING FOR CHEMISTS. KENSETH B. WIBERG. Pp. x + 269. New Yorli and Price (cloth) in the l7.S.A. $12.50; elsewhere I t should read “FORTRAN programming for chemists.” It deals only with FORTRAN 11, with a note on the modifications incorporated in FORTRAN IV, which is now replacing the earlier version, a mnemonic language devised for use with IB3I coin- puters.This language, with certain modifications and restrictions, may also be used with a few other makes of coniputer provided with punched card input and output, if FORTILkN compilers have been written for them. For the most part the text is written around the large, 32,768 ~ o r d , IBM-709, 7090, 7094 computers, but a few notes are added on the smaller II3M-1620 computer. i n addition, the longest chapter deals with assembly programmes FAP (for 709 antl i090 FORTRAN 11) and MAP (for 7090 and 7091 FOIiTliAN I V ) . For users of IBM machines and for others prepared to work within the facilities and restrictions of FOKTRAN 11, here is a pretty comprehensive treatment of programming in this language.They will furthermore have the benefit of an account written by a chemist, so that the illustrations of programmes and programme segments have a chemical flavour and use mathematics of a type familiar to chemists. Most books on the subject either deal only with the specification of the language, or provide mathematical or engineering iilustrations requiring some effort for assimi- iation before the programming aspects can be appreciated. The illustratlons in this book are real working programme3 of some lciigth culled from the author’s own interests in physical organic chemistry, and will be apprcciatively receivcd.The complete tyro can safely and confidently begin his study with this book, though perhaps more emphasis could have been placed on the general philosophy of computing and programming, and on the restrictions in the particular language under consideration. Programmers experienced in other languages will be able to assimilate the material quickly, but will find themselves asking questions which are not nnsn-ered explicitly, and to them the advice \voulcl be: “if it is not there you cannot do it.” For users of machines with piinched tape or film input and output provided with compilers for ALGOT, or their own mnemonic code, the benefit of this book lies in the extensive illustrations with a cheniical application. There is no doubt that a study of these programmes will be rewarding, but the treatment is exclusively FORTRAN, and direct translation will not produce the most economical programme in another language.For such programmers the very stiff price of the book will be an effective deterrant. E. BISHOP Amsterdam: JV. A. Benjamin Inc., 1965. $13.75. The title of this book is misleading. E. BISHOP OSCTLLOMETRY AND CONDUCTONETRY. By E. PUNGOR, D.Sc. Translated by T. DAMOKOS. Oxford, London, Edinburgh, hTew York, Paris Editor A. T~WNSHEXD. antl Frankfurt : Pergamon Press. 1965. Price 70s. Pp. svi + 238. The author observes in his introduction that the condiictometric titration of solutions was one of the first instrumental methods of analysis to be developed, and that now the oscillometric technique makes possible the examination of liquids contained in a closed system.The book is divided into five parts. Part I gives an adequate description of the theory underlying the measure- ments of conductivity and Cielccti-ic constant of solution. In Part I1 are described instruments340 BOOK REVIEWS [Analyst, VOl. 91 and apparatus for these measurements, in a thorough description occupying nearly one-third of the total text. A consideration of a variety of applications in acid - base titrations in aqueous and non-aqueous media is given, and also titrations based on precipitation and complex formation. Part V contains a discussion of the other applications of conductometry and oscillometry to subjects such as kinetic studies on the hydrolysis of esters, chromatography and establishment of phase diagrams.The latter is not completely error free, though in general mistakes appear to be nominal. It will be of value to analytical chemists either specialising in this subject or to those who wish to know its scope. There is also a bibliography with 374 references and a separate author index. This book is well produced and is clearly readable. V. J. JENNINGS STRUCTURE OF AQUEOUS ELECTROLYTE SOLVTIONS AND THE HYDRATION OF IONS. By 0. YA. SAMOILOV. Pp. xiv + 185. New York: Consultants Bureau. 1965. Price $15.00. In 1957, the Faraday Society held a Discussion on Interactions in Ionic Solutions, and one of the outstanding papers was that presented, in absentia, by Professor Samoilov of Moscow. To many of those present this was the first contact with the original and stimulating work of his Russian school. Since then a considerable effort has been made to bring the extensive results of their researches into the general orbit of English speaking peoples, and it has culminated in this esce!lent translation of Samoilov’s book.The book is concerned to give a clear and quantitative description of water and aqueous solutions, essentially in terms of the variable relaxation times of water molecules in the presence of ions and in the presence of other water molecules. The quasi-crystallinity of water resulting from the intense hydrogen bonding is shown to be disrupted by some solutes and enhanced by others (cf. the cluster models of Frank) and these features, referred to as negative and positive hydration, respectively, are related to observable properties such as fluidity and self-diffusion. This book is by far the best account of the properties of ions in aqueous solution, and it is devoid of much of the nonsense that is frequently presented under the heading of solvation.Even so, it perpetuates one or two attitudes with which this reviewer would quarrel. Once the word “struc- ture’’ is involved, it inevitably leads to a model which is too rigid and which is likely to obscure the most prominent feature of all liquids, namely Brownian motion. Furthermore, the failure to realise that density is the most discriminating variable of a liquid (and not temperature) leads to a restricted view of the kinetic picture. Nevertheless, in spite of these shortcomings (and it has to be realised that the subject of aqueous solutions is very wide and complicated), the book has a vitality and freshness reminiscent of Gurney.This English text has been prepared via the German text, and as such is third hand. However, the translator, D. J. G. Ives, is himself as authoritative as the original author, and a highly readable and accurate translation has resulted. There is no other comparable work and it is warmly recommended. G. J . HILLS SPECTROCHEMICAL ANALYSIS : OPTICAL SPECTROMETRY, X-RAY FLUORESCENCE SPECTROMETRY, AND ELECTRON PROBE MICROANALYSIS TECHNIQUES, JUNE 1964 TO JUNE 1965. Edited by ROURDON I;. SCRIBNER. Pp. x + 75. Washington, D.C.: U.S. Department of Commerce. 1065. Price 50 cents. The Analytical Chemistry Division of the National Bureau of Standards in tends to publish annual summaries of progress made by each of its sections during the preceding year.This first report of the Spectrochemical Analysis Section contains information in the fields of optical spectro- metry, X-ray fluorescence spectrometry and electron-probe microscopy. Examples of the subjects covered are excitation studies by arcs and sparks in controlled atmospheres and by the laser probe. The publication also includes sections on the measurement of arc-temperature, the use of continuum sources in atomic-absorption spectrometry and chemical and physical-enrichment methods for the analysis of high-purity platinum, tin and zinc. X-ray fluorescence spectrometric methods are dealt with for the analysis of silver and gold-base dental alloys and the determination of copper in brass by a solution procedure.An account of modifica- tions made to a recently installed electron-probe microanalyser, and examples of some applications of the instrument are also given. Workers in these fields who wish to keep up-to-date are always interested in developments in other laboratories, and these inexpensive publications should enable the progress of this well linown spectroscopic group to be followed. D. M. PEAKEMay, 19661 BOOK REVIEWS 341 QUAXTITATIVE ELECTRON MICROPROBE ANALYSIS. By ROGER THIESON. Pp. iv + 170. Berlin, In electron-probe microanalysis it is usual to make quantitative determinations by measuring characteristic X-ray intensities from the specimen and comparing these with similar measurements from high-purity elemental standards.A series of corrections must be applied to this crude ratio to give results of reasonable accuracy. This book details a method for converting the X-ray intensity ratio into mass concentration, taking simultaneous account of electron penetration, X-ray emission efficiency, mass absorption and electron back-scatter. The first 25 pagcs give the background to, and development of the theory on which the corrections are based. Six tables, covering 144 pages, enable the corrections to be carried out readily. The text is marred by a large number of typographical errors and incorrect equations that make development of the theory difficult to follow. This is the more unfortunate as the final equations differ significantly from those commonly used a t present.Little evidence is given for the reliability of the proposed method, and this limits the usefulness of the book. To operators of electron-probe microanalysis who wish to survey all the current correction theories, this book gives useful data for one theory, but until further evidence of reliability is forthcoming it cannot be recommended for general use. Heidelberg and New York: Springer-Verlag. 1965. Price DM 24. J. A. F. GIDLEY MISES AU P O I N T U E CHIMIE ANALYTIQUE ORGANIQUE, PHARMACEUTIQUE ET BKOMATOLOGIQUE. Douzikme Sbrie. Edited by J.-A. GAUTIER and P. MALANGEAU. Pp. ii + 239. Paris: Masson et Cie. 1964. Price Fr. 60. Triezikme Skrie. Edited by J.-A. GAUTIER and P. MALANGEAU. Pp. 236. Paris: Masson et Cie. 1964. Price Fr.66. “Afises uzt Point” continues its annual publications of reviews on various aspects of analytical chemistry. The twelfth issue has six contributions dealing with analytical control in the cereal products industries, organic peroxides, methods for the determination of the double bond, new aspects of the chromatography of carbohydrates, analytical control in the chocolate and confec- tionery trades and, finally, the study of fatty acids by gas chromatography. Moisture determination in cereal products is again given a detailed treatment with special emphasis on the Chopin multicellular drying-oven. Modern instrumental methods in cereal chem- istry are by no means overlooked, as, for example, the electrophoresis of gluten proteins and even moisture determination by nuclear magnetic resonance spectroscopy. The Kjeldahl method for the determination of total nitrogen in cereals is briefly discussed, but there is little practical guidance on this subject.Analytical control in the chocolate and confectionery trades is dealt with from the view- point of classical conventional methods, in spite of the title “Methodes analytiques recentes.” Organic peroxides, the carbon - carbon double bond and their determination are treated quite fully. Chromatography is represented by an article on the chromatography of sugars and carbo- hydrates, and by a study of gas chromatography of the fatty acids. Thc study of chromatography of sugars provides a useful starting point for the analyst unfamiliar with work in this field. Paper chromatography, thin-layer chromatography and gel-filtration separations of sugars are included, but not the gas chromatography of sugar derivatives such as the methylated sugars or trimethyl- silyl ethers.The article on the gas chromatography of fatty acids includes some useful results on the fatty acid composition of various oils and fats which are not, as yet, readily available in other reviews or reference books. The technique itself as applied to fatty acids is considered, particularly with reference to the problems likely to be encountered. The separation of linolenic and arachidic acids on the more polar polyester stationary phases is mentioned as a special difficulty, but is readily achieved by using the more sensitive ionisation detectors, more efficient columns and a less polar polyester stationary phase-a practice that is now a routine procedure in many labora- tories specialising in this field.The thirteenth issue of “Mises uzt Point” is entirely devoted to various aspects of food-colouring matters, both natural and artificial, The subject is treated from the view-point of French legisla- tion, but food chemists in this country may well find it useful to have a fairly comprehensive source of information a t hand on food colours. An unusual approach to the problem of the identification of food colours is the use of textile-dying techniques on various fibres, both natural and synthetic, in addition to the better known chromatographic methods. MISES AU POINT DE CHIMIE ANALVTIQUE ORGANIQUE, PHARMACEUTIQUE ET BKOMATOLOGIQUE.P. MORRIES342 ERRATA [A41zalyst, Vol. 91 PAPER -4ND THIN LAYER CHROMATOGRAPHY AXU ELECTROPHORESIS. A TEACHING LEVEL hlASUAL. Second Edition. By IVOR SMITH, B.Sc., Ph.D., F.R.I.C., M.I.Biol., and J. G. FEINRERG, B.Sc., M.Sc., D.V.M., M.I.Bio1. Pp. xvi + 241. London: Shandon Scientific Company Ltd., 1965. Price 36s. The first edition of this book appeared in 1962 and was reviewed in The Analyst, 1963, 88, 668. This second edition follows the same general pattern but is considerably enlarged. Two important new sections have been added: inorganic paper chromatography, written by the late Dr. F. H. Pollard and Dr. G. Nickless; and thin-layer chromatography written by Dr. I. Smith and Nrs. M. Smith. The original material has been improved, particularly by the inclusion of some additional experiments of biochemical interest. Any student, or indeed any chemist new to these types of chromatography, who makes use of this book will acquire a good working knowledge of, and possibly evcn an enthusiasm for, the techniques dcscribed. For the teacher there are available silent loop films in colour for use in conjunction with each section of the book; suggested commentaries appear in an appendix. Although the text is written around a proprietary set of apparatus, this in no way detracts from its value. Perhaps one of the avowed intentions of the book, i.e., to be an “aid to the busy teacher” is somewhat overdone. For example, each experiment is described fully, resulting in considerable duplication; this in itself is not serious, but it should be noted that the price of the book is rather high for a paper-back production. This, however, is a minor criticism of a useful introduction to these iniportant topics. J . F. HERRIXGSHAW

ISSN:0003-2654    

DOI:10.1039/AN9669100338

出版商:RSC    

年代:1966

数据来源: RSC

摘要:

342 ERRATA [A41zalyst, Vol. 91 Errata FEBRUARY (1965) ISSUE, p. 79, 1st line under REAGENTS. For “NN’-Dimeth?,lforutznlnicle” yead A U G ~ S T (1965) issuE, p. 497, heading in middle of page. For “ESTABLISHED I.C.U.M.S.A. DECEMBER (1965) ISSUE, p. 707, Fig. 4. Transistors TRl, TR, and TK, are shown wrongly con- The correction published in the February (1966) issue was incorrect in that no The circuit diagram between the secondary “N-Dirnethylformamide. ” ST.4NDARD METHOD I” Yead “TENTATIVE I.C.U.M.S.A. STANDARD METHOD I . ” nected. junction was shown between R26, C7 and TRI. of transformer T, and capacitor C, should be replaced by- FEBRUilRY (1966) ISSUE, p. 124, 4th line. For “123 ml” read “123 g.”

ISSN:0003-2654    

DOI:10.1039/AN9669100342

出版商:RSC    

年代:1966

数据来源: RSC