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June, 19671 A4NALYTICAL METHODS COMMITTEE 403 Analytical Methods Committee REPORT PREPARED BY THE METALLIC IMPURITIES IN ORGANIC MATTER SUB-COMMITTEE The Use of 50 per cent. Hydrogen Peroxide for the Destruction of Organic Matter THE Analytical Methods Committee has received the following Report from its Metallic Impurities in Organic Matter Sub-Committee. The Report has been approved by the Analytical Methods Committee and its publication has been authorised by the Council. REPORT The constitution of the Sub-committee responsible for the preparation of this Report was: Mr. W. C. Johnson (Chairman), Dr. J. C. Gage, Dr. T. T. Gorsuch (resigned November, 1966), Dr. R. A. Hoodless, Miss E. M. Johnson, Dr. H. Liebmann, Dr. R. F. Milton, Dr. E. J. Newman, Mr. W. L. Sheppard (resigned August, 1965) and Mr.G. B. Thackray, with Mr. P. W. Shallis as Secretary. In 1960, a Report1 was published from the Metallic Impurities in Organic Matter Sub- committee that described several procedures for the destruction of organic matter as a preliminary to the determination of trace metal impurities. These procedures were selected so as to provide for the wide variety of circumstances in which organic matter has to be destroyed, and various mixtures of nitric, perchloric and sulphuric acids were used as the oxidising reagents. Since the appearance of that Report, 50 per cent. hydrogen peroxide, of reagent purity, has become available, and two publi~ations,~J together with an earlier publication from the U.S.A.,4 have drawn attention to its use in the oxidation of many types of organic matter.Certain members of the Sub-committee have also acquired experience with the reagent, and one member has had routine experience with the oxidation of a large variety of foods and drinks with hydrogen peroxide, dealing with about 100 digestions per week over a period of 2 years. Further information on its use was also obtained in response to a notice in the “Proceedings of the Society.” The Sub-committee felt that these methods should be reviewed as an important supplement to those contained in the earlier Report. ADVANTAGES IN THE USE OF 50 PER CENT. HYDROGEN PEROXIDE The rapid but smooth oxidation of a wide variety of materials is possible. The reagent has been found particularly valuable in the rapid decomposition of some synthetic plastics that are resistant to the action of the oxidising acids.No objectionable fumes are evolved, except those from the sulphuric acid that must always be used with the reagent. Water is the only side-product from the reagent. Extremely low blank values can be expected in the determination of heavy metals. The reagent-grade peroxide may contain a trace (0-05 p.p.m.) of aluminium and silica; phosphate (a few p.p.m.) is added as a stabiliser and a trace of sodium (1 to 1.5 p.p.m.) is introduced incident ally. HAZARDS AND SAFETY PRECAUTIONS Fifty per cent. hydrogen peroxide should be stored in a cool place in polythene bottles. If the bottles are not provided with pressure vents, the stoppers or caps should be left loose. Contamination can lead to more or less vigorous evolution of oxygen, and completely sealed404 ANALYTICAL METHODS COMMITTEE [Analyst, Vol.92 bottles would then burst. Decomposition is catalysed by the presence of various metallic compounds, especially the oxides and hydroxides of the heavy metals, and by contact with precious metals, and it is accelerated by alkaline conditions. Whalley2 has given more detailed information on the decomposition of hydrogen peroxide and has provided a resumd of its chemical and physical properties. The reagent should be stored and used under such conditions that, through spillage, it does not come into contact with combustible materials. Spilled peroxide solution should be washed away at once with water, or wiped up with dilute ammonia solution, as higher concentrations are produced on evaporation, and spontaneous ignition of inflammable materials can result.Rubber or plastic gloves should be worn when handling the reagent. In contact with the skin it immediately produces the “white burns” that are obtained with 100-volume hydrogen peroxide, but the effect is more severe. Any burns must be washed immediately with water or dilute potassium permanganate solution, otherwise they will become painful and may cause blistering. Eye protection is essential, and oxidation procedures should be carried out behind a safety screen in a fume cupboard. For the purposes in consideration, 50 per cent. hydrogen peroxide must always be used in conjunction with a sufficient amount of sulphuric acid. Whalley2 refers to the part played by Caro’s acid (peroxymonosulphuric acid) in the oxidations.A Sub-committee member produced explosions deliberately by evaporating large volumes (about 50 ml) of peroxide with small volumes (less than 5 ml) of sulphuric acid. Though noisy, the explosions did not produce mechanical fracture of the glassware involved. In the methods described below a much greater proportion of sulphuric acid is always present. As with most methods for the destructive oxidation of organic matter, it is an elementary precaution to observe the behaviour of any new material in a small-scale preliminary experiment. METHODS It is perhaps obvious that no precisely standardised procedure can be laid down for application in all circumstances. The procedures described in the following paragraphs are drawn from the various sources acknowledged at the beginning of the Report and the variations arise, in the main, from the nature of the samples with which the contributors were concerned and their ease or difficulty of oxidation with hydrogen peroxide.Users will adapt the detail of the procedures to their own particular circumstances. APPARATUS- Oxidations can be conveniently carried out in Kjeldahl flasks and one of 100-ml capacity is generally suitable for the oxidation of 2-g amounts of organic material. When such a flask is used it is convenient to add the hydrogen peroxide from a small tap funnel, but as grease of any kind must not be used the stopcock must be fitted with a PTFE plug. The stem of the funnel should be bent in such a way that condensation of the vapours on the funnel does not occur.If there is a possibility that constituents subsequently to be determined may be lost through volatilisation, the apparatus described by Whalley5 should be used with a condenser. Alternatively, the apparatus of Bethge,6 or its modified form,2 may be used. PROCEDURE A297 (for plastics and other w.tateriaLs)- Place the sample (2 g) in the flask and add 5 to 25 ml of concentrated sulphuric acid. Heat until charring occurs, and then add 50 per cent. hydrogen peroxide dropwise until a colourless solution is obtained. With some substances alternate charring and addition of hydrogen peroxide is necessary, but care must be taken to ensure that the amount of sulphuric acid is not greatly reduced by evaporation (see “Hazards” above).Excessive charring should be avoided, as the carbon so formed will be difficult to disperse and will subsequently cause trouble. If this point is reached it is best to discard the experiment and start again with a fresh sample.June, 19671 ANALYTICAL METHODS COMMITTEE TABLE I WET DESTRUCTION OF ORGANIC MATTER WITH 50 PER CENT. w/w HYDROGEN PEROXIDE 405 Sulphuric acid fuming when hydrogen peroxide added - > Volume of Volume of Time for Material H207J H2S0, complete (2 g taken in each 50% w/w, (sp.gr. 1.84), destruction, experiment) ml ml minutes Soya bean oil . . . . 15 to20 10 15 to 20 Sawdust .. . . 15 to 20 10 10 to 15 Wool . . . . . . 10to 15 10 10 Cotton . . . . . . 10to 15 10 10 Nylon . . .. .. 15to20 20 10 to 15 Terylene . . .. 15 to 20 15 10 Poly(viny1 chloride) . . 20 to 25 10 10 to 15 Polythcne . . . . 20 to 25 20 20 Cheese . . . . . . 15to 20 10 10 Meat . . . . . . 10to 15 10 10 8-Hydroxyquinoline . . 10 to 15 10 10 Lubricating oil . . 15to20 10 20 Cabbage . . . . 5 t o 10 10 5 t o 10 Sulphuric acid not fuming when hydrogen peroxide added 1 Volume of H@2J 50% w/w, ml 10 to 15 20 to 25 10 to 15 5 10 to 15 10 to 15 20 20 to 25 20 to 25 25 to 30 10 to 15 10 to 15 15 to 20 Volume of (sp.gr. 1-84), ml 5 10 5 5 5 5 10 10 10 20 5 5 5 HZSO, 1 Time for complete iestruction, minutes 20 30 10 to 15 10 10 10 to 15 15 25 20 to 25 30 to 35 10 to 15 10 10 to 15 Table I summarises the experience of Whalley2 with a variety of organic materials. Procedure A was used with the initial addition of a catalytic ion, such as manganese or vanadium.Later contributors do not appear to have found catalysts necessary, and Whalley7 now uses them only when decomposing materials that are not themselves likely to contain catalytic metals . A member of the Sub-committee has applied Procedure A to some plastics and has provided the information given in Table 11. TABLE I1 DESTRUCTION OF ORGANIC MATTER Volume of Plastic peroxide, ml PVC for foodstuffs . . .. 20 Polypropylene . . .. 60 Polythene . . . . . . 20 Urea - formaldehyde . . 8 Melamine - formaldehyde . . 8 Perspex piece . . . f 8 Perspex powder granules . . 35 Butyl rubber . . . . 60 Time taken, minutes 10 10 60 18 2 to 3 Largelv BY PROCEDURE A Comments At one stage the mixture was allowed to cool and 2 to 3 ml of 50 per cent.H20, were added. This brought about a large reduction in the amount of carbon present Colourless solution when heated to white fumes - Small pieces became coated with carbon unaff ec&ddafter 20 minutes 60 Incomplete after 60 minutes A correspondent has used the same type of treatment for samples (2 to 10 g) of formic, acetic, propionic, succinic, fumaric and sorbic acids, as a preliminary to trace metal deter- minations. Taubinger and Wilson3 adopted similar conditions using always 20 ml of concentrated sulphuric acid, They oxidised successfully several synthetic plastic materials, and the details of the amounts of hydrogen peroxide consumed and the times taken for the complete oxidation of each substance are tabulated in their papere3 These authors found that carbon black and polytetrafluoroethylene were not attacked by hydrogen peroxide, and liquid paraffin406 ANALYTICAL METHODS COMMITTEE [Analyst, Vol.92 reacted so vigorously that its oxidation under these conditions was considered dangerous. Tritolyl phosphate and olive oil frothed excessively and were more satisfactorily treated by Procedure B. PROCEDURE B (for readily oxidisable materials)- Add 20ml of concentrated sulphuric acid to 2 g of the organic material and, to the cold mixture, add 50 per cent. hydrogen peroxide dropwise until the reaction slows up (the heat produced will be sufficient to maintain the reaction) or until the solution becomes colourless. Then heat the solution until fumes of sulphuric acid are evolved, adding more hydrogen peroxide as necessary until a colourless solution is obtained.Taubinger and Wilson3 oxidised tritolyl phosphate and olive oil by this procedure. A Sub-committee member uses this type of procedure for the oxidation of solid fruits, vegetables, meat, and milk products, and sometimes finds it necessary to initiate the reaction by gentle warming, which is applied if the reaction does not begin within 2 minutes after the addition of hydrogen peroxide. This contributor recommends the addition of a few glass beads at the outset of the experiment. PROCEDURE C (for soft drinks, beers, etc.)- To a 250-ml flask add several glass beads and 5 ml of concentrated sulphuric acid. Add the sample (not more than 50 ml) and then 20 ml of 50 per cent. hydrogen peroxide, and heat gently until the initial reaction has ceased.Then heat until fumes of sulphuric acid are evolved. If at any stage charring occurs, add further 1-ml portions (not greater) of hydrogen peroxide. If at any stage it seems that the sulphuric acid may approach dryness, cool, add 2 to 3 ml of sulphuric acid, and continue. PROCEDURE D (for syru+s)- To a 500-ml flask containing the sample (not more than 50 ml) add several glass beads, 50 ml of water, 5 ml of concentrated sulphuric acid and then 20 ml of 50 per cent. hydrogen peroxide. Heat gently until the initial reaction has ceased. If the solution is dark, repeat the peroxide addition, several times if necessary, and, when reduced to a small bulk, heat strongly to fumes of sulphuric acid. If charring occurs, add further 1-ml portions (not greater) of hydrogen peroxide until the fuming sulphuric acid remains colourless. If at any stage it seems that the sulphuric acid may approach dryness, cool, add 2 to 3 ml of sulphuric acid, and continue.The member who provided this method found it especially suitable for preventing excessive carbonisation of carbohydrates. Digestion is complete when the fuming sulphuric acid remains colourless. PROCEDURE E (for herbs, spices, gums, etc.)- Mix the sample (2 to 5g) with the minimum amount of water to form a slurry, and add concentrated sulphuric acid (3 to 5 ml). Heat the mixture gently and add 50 per cent. hydrogen peroxide dropwise, ensuring that all the peroxide has decomposed before making further additions. When the bulk of the sample has decomposed, add more peroxide until a clear fuming liquid is obtained.The contributor who provided these details has used this procedure for curry powder, acacia, tragacanth and chlorophyll. With certain oils and balsams, e.g., oil of copaiba balsam and Peru balsam, 50 per cent. hydrogen peroxide was found to be too vigorous for safe and accurate work. CONCLUSIONS From the information made available, the Sub-committee was satisfied that the advan- tages set out on p. 403 had been established, and that 50 per cent. hydrogen peroxide provides a convenient and effective means of destroying organic matter. Although it is known that the reagent has been used as a preliminary to the determination of several metals, the Sub-committee has not conducted a systematic examination of the possible effects of treatment with hydrogen peroxide on the subsequent recovery and determination of trace metals. I t is intended to take this aspect into account in future reportsJune, 19671 ANALYTICAL METHODS COMMITTEE 407 from the Sub-committee. However, since the preparation of this Report the Sub-committee has become aware of a papers giving the results of a study of the recovery of several elements, at the parts per million level, from organic materials after oxidation with sulphuric acid and 50 per cent. hydrogen peroxide. REFERENCES 1. 2. 3. 4. 5. 6. 7. 8. Analytical Methods Committee, Analyst, 1960, 85, 643. Whalley, C., in West, P. W., Macdonald, A. M. G., and West, T. S., Editors, “Analytical Chemistry Taubinger, R. P., and Wilson, J. R., Analyst, 1965, 90, 429. Polley, D., and Miller, V. L., Analyt. Chem., 1955, 27, 1162. Whalley, C., Paint Technol., 1956, 20, 47. Bethge, P. O., Analytica Chim. Acta, 1954, 10, 317. Whalley, C., personal communication to the Sub-committee. Down, J. L., and Gorsuch, T. T., Analyst, 1967, 92, 398. 1962,” Elsevier Publishing Company, Amsterdam, London and New York, 1963, p. 397.

ISSN:0003-2654    

DOI:10.1039/AN9679200403

出版商:RSC    

年代:1967

数据来源: RSC

摘要:

408 Book Reviews [Analyst, Vol. 92 OILS, FATS AND FATTY FOODS. THEIR PRACTICAL EXAMINATION. Fourth Edition. By K. A. WILLIAMS, B.Sc., Ph.D., M.Inst.Pet., A.Inst.P., F.R.I.C. Pp. viii + 488. London: J. & A. Churchill Ltd. 1966. Price 100s. We welcome the new edition of this book, which to many chemists needs no introduction. Being a person of conservative tastes I find it pleasing that in the revision the lay-out of the book remains the same as that which has been familiar to us for many years, but for the benefit of those who are not familiar with this work a brief description of the contents may be helpful. The earlier chapters are devoted to a description of the general chemical and physical tests that are used in the analysis of oils and fats, and these are followed by a chapter on the interpretation of results.It is in this early part of the book that we obtain the full benefit of the author’s lifetime of experience in the practical examination of oils and fats. The full title of the book is “Oils, Fats and Fatty Foods-Their Practical Examination.” The book undoubtedly lives up to this ancillary title, and is enriched by much practical know-how that can only have becn acquired by long experience of the snags involved from a practical point of view. The chapter on interpretation similarly reflects the author’s appreciation of the need for guidance on this subject, as the mere determination of the constants for an oil or fat can be of little value without a knowledge of how they are related to composition; this is an aspect of the examina- tion of oils and fats that is often omitted in books on this subject. Chapters on the industrial production of oils and fats and hardened oils follow, and then important fats such as butter, margarine and lard each receive extensive individual treatment.The description and properties of vegetable oils occupy a substantial proportion of the book, some 140 different oils being described together with botanical details of the nuts, seeds, etc., from which they are derived. This section of the book would be a work of reference in its own right without the other sections. It includes oils that are infrequently used in commerce and on which it is difficult to find detailed information in the literature. The composition of the cakes remaining after extraction of the oil, many of which are used for animal feeding stuffs, are also given.The closing chapters deal with miscellaneous fatty foods such as cocoa, milk products and animal feeding stuffs. The entire book has been revised and brought up to date as far as is possible in an age of rapidly changing techniques and rapid accumulation of new knowledge, and many new methods of analysis for oils and fats have been introduced since the last edition of this book, of which mention may be made of gas and thin-layer chromatography and lipase hydrolysis. In view of the valuable information that can be obtained from these techniques one would have liked a larger proportion of the book to have been devoted to them, but it may be that the author feels that the results arc as yet not sufficiently firmly established to warrant the methods being discussed in greater detail.Fats and fatty foods are the subject of a number of Government Standards and full details of the latest requirements are given in the text. The book also includes a list of standards for oils and fats in some of the more important countries in a special appendix. This appendix also includes a list of possible new sources of oil which have been investigated in recent years. We are indebted to Dr. Williams for a new edition of a book that has been proved by long experience to be invaluable to all concerned in the analysis of oils and fats. J. H. HAMENCE MODERN TRENDS IN ACTIVATION ANALYSIS. Proceedings of the 1965 International Conference a t College Station, Texas, U.S.A.April 19-22, 1965. Pp. 390. Texas A & M University Press. Price $15; 128s. At a time when activation analysis and related methods are being investigated by scientists of a variety of persuasions, chemists, physicists, metallurgists, instrumental specialists, etc., it is becoming increasingly difficult to follow developments in applications and techniques without an extensive survey of the literature. “Modern Trends in Activation Analysis” contains more than seventy papers on a variety of aspects of activation analysis which were presented to the Texas Conference, in many cases by established workers in their own fields, and provides, within one volume, much useful information and a guide to the fields of research attracting attention at present.Subjects of the papers include reactor neutron-activation analysis, computer techniques,June, 19671 BOOK REVIEWS 409 fast neutron, y-photon and charged particle activation, secondary reactions, prompt radiation techniques and electron activation. The largest number of papers are concerned with reactor neutron-activation, and methods for the determination of many elements in a variety of different matrices are described. In spite of the increasing emphasis on sophisticated instrumental techniques, the high de- contamination factors that can be obtained by chemical separation still make this an attractive method of isolating the activity to be determined from all others induced in the sample, particularly for trace element determination, and several papers on chemical separation techniques are included, which in some cases describe automatic systems designed to free laboratory staff from repetitive operations.Instrumental methods receiving attention are not only techniques of y-ray spectro- scopy, such as coincidence methods and the use of germanium counters, but also the handling and processing of data in computer systems. Oxygen determinations figure largely in papers on fast-neutron activation analysis, but automated and sealed-tube systems are also described. Of the less widely applied activation techniques that are the subjects of papers, helium-3, proton, deuteron and y-photon activation and secondary reactions are discussed as a means of determining light elements that cannot be assayed by conventional reactor neutron activation, and examples are given of methods based on the measurement of “prompt” radiation emitted as a result of such processes as Rutherford scattering, inelastic scattering and radiative capture. The appendix of the book contains a recommended method for the measurement of neutron flux emitted by a neutron generator by the T (d,n) 4He reaction, and is based on assay of the activity induced in a copper foil.This book is a straightforward collection of research papers delivered to the Conference, and, as such, will appeal primarily to those who are already familiar with activation techniques. In spite of the fact that a few of the papers have appeared in thinly disguised forms elsewhere in the scientific literature, the largest amount of information in this book will recommend i t to those interested in keeping abreast of developments in nuclear analytical techniques.T. B. PIERCE ELEMENTARY PRACTICAL ORGANIC CHEMISTRY. PART 1 : SMALL SCALE PREPARATIONS. By ARTHUR I. VOGEL, D.Sc., D.I.C., F.R.I.C. Second Edition. Pp. xx + 435. London: Longmans, Green and Co. Ltd. 1966. Price 35s. By ARTHUR I. VOGEL, D.Sc., D.I.C., F.R.I.C. Second Edition. Pp. xvi + 431. London: Longmans, Green and Co. Ltd. 1966. Price 35s. A complete course of practical organic chemistry would necessarily include the preparation of organic compounds including, in advanced stages, the synthesis of compounds of complicated structure ; the qualitative identification of compounds including the fragments obtained by the degradation of complex molecules and their quantitative determination alone and in mixtures. Our brief span limits organised courses to about 3 years and restricts them generally to what we call elementary practical organic chemistry, but the elementary of today was the recondite of a previous generation.Hence the need for the constant renewal of text-books for the student. This need has been met in Dr. Vogel’s well known trilogy consisting of the two volumes now reviewed and the companion volume on Quantitative Organic Analysis. The first two, issued in 1957, and running into five impressions, have now appeared in a second edition, which will long preserve the memory of their author among both teachers and students. Part 1, Small Scale Preparations, is characterised by the inclusion of new apparatus and the new experimental techniques of paper, thin-layer and ion-exchange chromatography and by descriptions of the mechanisms of the reactions described in the various preparations.New preparations are also included. The first three chapters deal with the fundamental bases, viz., determination of physical constants, the elementary composition, and solubility as a criterion of classification. Then follow three chapters on class and functional group reactions and the preparation of derivatives for identifica- tion. A chapter on the analysis of mixtures is then followed by an important new chapter dealing with the practical essentials of ultraviolet and infrared spectroscopy, nuclear magnetic resonance spectroscopy and mass spectrometry, techniques and apparatus which have already largely become tools of everyday use in both teaching and industrial laboratories.Finally, 100 pages are devoted to tables of physical constants of compounds and their derivatives, which constants form an integral part of organic analysis in contrast to inorganic analysis. ELEMENT*\RY PRACTICAL ORGANICHEMISTRY. PART 2 : QUALITATIVE ORGANIC ANALYSIS. Part 2 . Qualitative Organic Analysis has been completely re-arranged and extended.410 BOOK REVIEWS [Analyst, VOl. 92 Both parts are written with the logic and lucidity that is characteristic of Dr. Vogel’s well known text-books and fully justify their claims to meet the requirements up to the honours degrees of the universities, and are equally valuable in industrial laboratories. J.I. M. JONES FORMULA INDEX TO NMR LITERATURE DATA. Volume 2 : 1961-1962 References. Edited by Pp. x + 516. New This is the second volume of literature references to high resolution nuclear magnetic resonance spectra to come from the research laboratories of the American Cyanamid Company. Volume 1 covered references prior to 1961 whereas Volume 2 is confined to references in the literature for 1961-62. The format of the new volume is identical with the previous one. Compounds are listed in order of empirical molecular formula and also by structural formula when this is known. The fact that this volume is twice the size of the previous one illustrates the remarkable development of the n.m.r. technique in recent years. It is hoped that the contributors will not feel disillusioned a t this increasing pace in the development of the subject and that further volumes are planned, otherwise these present two volumes will lose much of their usefulness.The high price of this second volume is not unexpected in a reference book of this type, and the book is certainly recommended for any n.m.r. spectroscopy laboratory. M. GERTRUDE HOWELL, ANDREW S. KENDE and JOHN S. WEBB. York: Plenum Press Data Division, 1966. Price $22.50. K. G. ORRELL HANDBUCH DER ANALYTISCHEN CHEMIE. Edited by W. FRESENIUS and G. JANDER. By DR. GUNTHER KRAFT. Part 3: QUANTITATIVE BESTIMMUNGS- UND TRENNUNGS-METHODEN. BAND IV ap. ELEMENTE DER VIERTEN HAUPTGRUPPE I1 - IV GERMANIUM - BLEI. Pp. xvi + 222. Berlin, Heidelberg and New York: Springer-Verlag. 1966. Price (Linen covered) DM 64; (Hard backed) DM 59.Both follow the same pattern : gravimetric, titrimetric, photometric, polarographic, spectrochemical and radiochemical methods are discussed in turn ; useful chapters on the separation of these elements from probable interferences are included. Methods for the analysis of elemental germanium, and germanium oxide and chloride are given, because of the great importance of these materials in semiconductors. The volumes of this Handbuch have no real parallel in the English literature. The information given is much more extensive than that in any comparable text in English; for example, there is full experimental detail for no fewer than twenty three photometric methods of determining ger- manium and many other methods are mentioned.The desirability of this proliferation of detail is arguable, but it does mean that, without recourse to the original literature, the careful reader can choose a method on the basis of his own evaluation of the various possibilities, rather than on the prejudices of the author. The whole book is a fine example of the assiduous Germanic approach. It should be of great value to anyone engaged either in analysis for germanium and lead or in the production of lesser compilations. A. M. G. MACDONALD This book comprises two monographs on the determination of germanium and lead. VACUUM MICROBALANCE TECHNIQUES. Volume 5. Proceedings of the Princeton Conference September 27-28, 1965. Edited by KLAUS H. BEHRNDT. Pp. xx + 264. New York: Plenum Press. 1966. Price $13.50. The justification for the annual appearance of volumes such as this should be that they survey progress in rapidly advancing areas of science. However, even more than preceding volumes, “Vacuum Microbalance Techniques,’’ Volume 5, leaves the impression that the field covered is too restricted for a worthwhile annual publication, and it is poor value a t $13.50. For analytical chemists the book contains little new information likely to be of value in the application of microbalances. Seven of the papers are detailed theoretical analyses of particular aspects of microbalance performance. Knudsen forces in the intermediate pressure range are the subject of three papers, and the importance of avoiding the difficulties of making reliable corrections for their effect is emphasised. The effects of gas pressure and added-mass on quartz crystal microbalances are discussed a t length by Stockbridge. Applications of microbalances to studies of the impulse of an ion engine for space propulsion, sputtering yields, magnetic suscepti- bility, and problems in thin-film deposition are described in other papers. D. W. BASSETT

ISSN:0003-2654    

DOI:10.1039/AN9679200408

出版商:RSC    

年代:1967

数据来源: RSC