Capillary electrophoresis - ACS Publications - American Chemical

Anal. Chem. 1990, 62, 5QR-7QR

Nuclear and Radiochemical Analysis William D. Ehmann,* J. David Robertson, and Steven W. Yates Department of Chemistry, University of Kentucky, Lexington, Kentucky 40506-0055

For our third review under the present title, we have added a coauthor whose expertise will provide added depth to several areas of our review. Welcome aboard Dave! In examining the recent literature, we note that there has been a significant growth in the number of a plications of Rutherford backscatterin spectroscopy (RB ), particle-induced y-ray emission (PIGb), particleinduced X-ray emission (PIXE), and nuclear microprobe techniques. Because PIXE is adequately covered in other reviews, our coverage of this technique will be limited to those applications where it is used simultaneously with nuclear reaction techniques. Similarly, we have chosen not to review research papers dealin solely with health physics, nuclear spectroscopy (unless firectly related to analysis), plasma desorption mass spectrometry, nuclear engineering, fusion, fallout, radioactive waste disposal technology, nuclear and particle physics, radioimmunoassay, Mossbauer spectroscopy,and isotope dilution anal sis with stable enriched isotopes. These topics are covered aiTuately in other reviews. Papers on nuclear dating methods an tracer techniques are often directed toward specific ap lications and are treated only briefly here. However, Table fdoes include references to selected new books and current reviews on many of the above topics in order to guide the reader to other sources of information. The reader should be aware that references to the books and reviews in section A and Table I of this review are not necessarily repeated in later sections which deal with research ublications on specific topics. Finally, in the section entitled kelated Topics we free ourselves of the above restrictions and briefly highlight some nonanalytical topics that we feel may be of general interest to radiochemists. This year’s review is based rimarily on a computerized search of Chemical Abstracts (EA),Index Volumes 108-111, covering the period January 1,1988, to November 1, 1989. Articles appearin late in 1989, or in less widely circulated journals, may not%e included here due to the time required for abstracting. The rimary search term “radiochemical analysis” yielded 631 afstracb, excludin patents. A search based on the term *isotopic dating” profuced an additional 78 references. When ion beam techniques were found to be underrepresented in the CA search, an independent computerized search of the INSPEC (Information Service for Physics and Engineering Communities) database for the same period found approximately 250 publications under the keywords “PIXE” and “ion beam analysis”. Surprisingly, most of the latter were not duplicated in the CA search. In addition to excluding patents, we have also generally excluded agency, laboratory, or industry reporb that do not receive wide circulation, less accessible conference proceedings, and publications in the less common languages. Exceptions are made where the material is unique and not well represented in other ublications. In the latter case, and for all non-English u&ications, Chemical Abstracts or Physics Abstracts (Pi) citations are appended to the references. It should be noted that many pa ers on nuclear methods of analysis are also listed on the &IS (International Nuclear Information System) computerized database, operated by the International Atomic Energy Agency, Box A-1400, Vienna, Austria. The latter database was not searched for this review

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and the degree of overlap with CA and PA is not known to us at this time. We again urge authors to use the keywords “radiochemical analysis” in any list provided to the publishers, since the abstracting services catagorize most nuclear methods of analysis under this phrase. In response to a general request by the Editor of the Fundamental Reviews issue, we have attempted to shorten the review this year. We do not claim that the citations we have included are a complete coverage of the field; however, it is our hope that our selections will provide the readers with pathways to other literature in their fields of interest.

A. BOOKS AND REVIEWS As in our previous reviews, we have separated comprehensive books and reviews from original research contributions. A classified list of these works is presented in Table I (AI-Al29). We are particularly pleased to note that many new books have been published in the fields of nuclear chemist radiochemistry, nuclear methods of analysis, and relaterkubjects. As has been our practice for such special contributions, we will provide a brief summary of the contents of some of these mono aphs. Nuclear fiuironmental Chemical Analysis by J. Tolgyessy and E. H. Klehr ( A I I I ) is a verv useful reference book for scientists who wish to apply radioanalytical methods to the field of environmental science. The first chapter includes a survey of techniques that have been applied to environmental samples. Included are concentration ranges, selectivity, analysis time, a proximate cost, and various specific advantages and disadktages of each method. In Chapter 2, an excellent review is provided of methods of samplin the atmosphere, natural waters, biological samples, and tke lithosphere, with illustrations of many of the most common types of sampling devices. The thiid chapter provides a brief review of reference standards suitable for environmental analyses and advice on preanalysis sampling handling. In the remaining cha ters, the basic rinciples of the various radioanalytical rnet\ods that have {een a plied to environmental samples are discussed. These metfods include direct measurement of natural and man-made radioactivities, isotope dilution analysis, radioreagent (includin radiorelease) methods, nuby scattering absorption clear activation analysis, and and X-ray fluorescence. The final chapter consista of a listing of sources of information that are available on different aspects of environmental chemistry and the analytical techniques employed in the field. The book will be useful to scientist8 in the field of environmental chemistry who wish to evaluate the potential a plications of nuclear methods to analysis and will also provile the radioanalytical chemist with much valuable information on environmental sampling, handling, and storage techniques. Activation Analysis with Charged Particles by C . Vandecasteele (A26)is part of the Ellis Horwood continuing series in analytical chemistry. This rather ex ensive volume is directed to the analytical chemist with lit& or no experience in nuclear methods of analysis. The first three chapters cover

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NUCLEAR AND RADIOCHEMICAL ANALYSIS Wllllam D. Ehmann is a professor in me ' Chemistry Lhpanment 01 the University of Kentucky. He received his B.S. and M.S. degrees in chemistry from the University of Wisconsin. Madison. and his Ph.0 in radiochemistry from Carnegie Institme of Tech nology (now Carnegie-Meiion Univer~ity)in 1957. After a year 01 postdoctoral research at Argonne National Laboratwy. Or. Ehmann joined the faculty 01 the University of Kentucky in 1958. At the University of Kenlucky he has been elected Distinguished ! Professor 01 the College of Ans and Sciences. appointed University Research PTD feasor. received the Slurgill Award for his - ' contributions to gradmate education. and S B N ~as~Chalrrnan of the Department Of Chemism and Associate Dean fW Research in the Gradmate School. He has been a Fuibright Research Fellow at the Institute 01 Advanced Studies 01 the Ausnaiian National University and a visiting Scholar at Arizona State Universlcl and Florida State Universlcl. His research interests include innovative approaches to trace element anaiyiical chemistry using nuclear methods. especially as applied to research problems in geochemistry and cosmochemistry. arm the relationships of brain trace element imbalances to neumiogical diseases Such a$ Alzheimer's disease and ALS.

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J. Davkl -R is an assistant p~olessw in the Chemistry Depanment O f the University of Kentucky. He received his B.S. degree in chemistry hom the Universily 01 Missouri at Columbia in 1982 and his Ph.0. in nuclear chemistry from the Univeroily of Maryiand at College Pa* in 1986. After 2 years of postdoctoral research at the Lawrence Berkeley Laboratory. Dr. Robertson Joined the faculty at the University of KentUCky in 1989. His research interests are focused on the development of acceierator-based trace element analysis techniques and the subsequent application 01 these techniques to fundamental problems in a variety of areas. Current applications include research problems in the prdudion 01 ion-conducting thin films and thin film devices. the relationShips 01 trace element imbalances to the neurological diseases associated with aging, and the effects of various compounds on the blood-brain barrier. In BWibn to nuciear memods of analysis. Dr. RobenSon occasionally returns to studies of the decay m d e s and structure of nuclei far from stability.

Steven W. Vales Is a prolessor in the Chemistry Depanment of the University of Kentucky. Ha received his B.S.degree in Chemistry from the University of Missouri at Columbia and his Ph.0. in nuclear chemistry from Purdue University (1973). After 2 years of posmmorai research at ~ r ~ n n e 'f ,'' National Laboratory. Dr. YateS joined the ''!it.-facuity at the University of Kentucky in .1975. He has S B N ~as the Director of General Chemistry at the UniversBy and received the University Of Kentucky Research Foundalbn Award in 1981. Dr. Yates was a viSiting scbiar at the KFAJiiiich. West Germany, in 1981 and is Currently On sabbatica leave at Lawrence Livermore National Laboratory He will serve as the Chairman Of the Division Of Nuclear Chemistry and Technology 01 the American Chemical Society in 1992. His research monshave been primariiy in basic nuclear spectroscopy and nuclear structure studies of deformed and transnional nuclei. but he makes an occasionai excursion into applying accelerator-bared techniques for elemental analysis.

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the basic principles, equipment, and techniques of chargedparticle activation analysis. The remainder of the hook is devoted to descriptions of specific applications with special emphasis given to the trace element analysis of metals and semiconductors. Also included in this latter section is a practical discussion of the thermal behavior of geological, environmental, and biological samples in charged-particle activation analysis. The extensive bibliographies provided at the end of each chapter will be very helpful to those seeking more detailed inforrnat.inn. The Crumbs of Creation by J. Lenihan (A5) is a highly entertainiz, ljttle volume dealing with trace elements in history, m sine, industry, crime, and folklore. It is included in this review since many of the applications cited involve neutron activation analysis. Topics relating to toxic elements and forensic applications are emphasized. The anecdotal text ~

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b Lenihan combined with humorous illustrations by J. Ffeming provide the reader with accurate and useful information in a bright and engaging style. Radruanal)cis in Ceochemislry, written by H. A. Das, A. Faanhoi, and H. A. van der Slwt ( A I 1.51. is volume 5 in a series entitled I k t clupmenrc in Crochemisrr>. This cnstly volume provides a broad introduction to the use of a wide variety of nuclear analytical techniques in geochemistry. Among the techniques and topics presented are INAA, RNAA, CPAA, HIAA, PGNAA, IPAA, PIXE, PIGE, laboratory and field methods utilizing tracers, measurements of levels of natural radioactivities, in situ analyses by EDXRF, NAA, PGNAA, and scattering methods. The presentation typically involves an initial brief introduction to the principles of each technique written for the nonexpert, then a discussion of the practical aspects of applying the technique, and finally a selection of illustrative examples with a generous bibliography to guide the reader to other applications. In many cases, material is presented in tables or an outline format that makes information easy to find, but rather disjointed to read. Applications of nuclear methods of analysis to surface, ground, and seawater samples, as well as to rocks and sediments, are included. The discussions of sampling and preconcentration of geological and water samples are especially useful. The chapter on RNAA techniques provides an excellent summary of group separation techniques that have been applied to geological samples. Important single-element RNAA separations are also presented in a brief outline format. The book is not directed to the expert in nuclear methods of analysis but rather to the geologist, geochemist, or geophysicist who would like to investigate potential applications of nuclear methods to study variations in elemental concentrations, to use tracers to study transport phenomena, or to measure natural radioactivities for exploration purposes or environmental studies. The second edition of Radiation Detection and Measurement by G. F. Knoll (A911 is an update of his original 1979 work. The organization by chapters is unchanged in the new edition, although some changes were made in sequencing the The most extensive changes are reflected in the treatment of the new high-purity germanium (HPGe) detectors for high-resolution y-ray spectrometry and the use of photodiodes to convert light emitted in scintillation systems. Other topics receiving additional emphasis include chargedparticle spectroscopy with ion chambers, BGO and BaF, scintillation detectors, new types of photomultiplier tubes, fully depleted silicon detectors, passivated planar silicon detectors, the derivation of field configuration and pulse shape in coaxial geometry, CdTe and HgI, detectors, and pulse pileup considerations. This clearly written hook serves both as a textbwk for upper division undergraduate and first year graduate students and as a well-referenced sourcebwk for the practitioner in the field of radiation measurements. Illustrative problems are included at the end of each chapter and a solutions manual is available. This affordable volume is a "must" for all laboratories where graduate students are introduced to the instrumentation required for nuclear methods of analysis, Techniques for Nuclear and Particle Physics Experiments by W. R. Leo (A%') is essentially the lecture portion of an advanced laboratory course in experimental nuclear and particle physics taught by the author to physics majors at the University of Geneva. This modestly priced soft-cover volume was published in late 1987. Chapters deal with basic nuclear properties, passage of radiation through matter, health physics, statistics in radioactive decay, counting instrumentation, electronics for pulse signal processing, pulse height selection, coincidence techniques, electronic logic, timing methods, and CAMAC systems. It should he made clear that this is not a laboratory manual in the usual sense of a collection of specific experiments. Some experiments are briefly outlined as examples, hut it is left to the instructor to develop experiments based on the principles that are presented in the text. Little prior knowledge is assumed and topics range from cable termination and oscilloscope operation to fundamental laws of Boolean logic and sophisticated timing methods in radiation detection. Not all the topics covered would be essential for the typical radiochemistry graduate student, but portions of the book provide some of the most succinct and clearly written descriptions of detectors, basic statistics, and nuclear electronics that are available. This book should be in the library ANALYTICAL CHEMISTRY, VOL. 62, NO. 12. JUNE 15. 1990 * 51 R

NUCLEAR AND RADIOCHEMICAL ANALYSIS

of any university that has a graduate program in nuclear or radiochemistry. Ion Beams for Materials Analysis, edited by J. R. Bird and J. S. Williams (A66),was compiled to introduce the general researcher to the numerous ion beam analytical techniques that have been develo ed over the last 2 decades. As noted in the preface, the wor! seeks to help the nonspecialist decide when ion beam analysis (IBA) would be more useful than other, more familiar analytical methods and to ive the general researcher enough practical information to m&e effective use of IBA. The first two chapters introduce the reader to the basic concepts and principles of ion interactions with materials and to the basic procedures and equipment of various IBA techniques. Dehled descriptions of high- and low-ener scattering spectrometry, nuclear reaction analysis, ion-in uced ion X-ray emission spectrometry, channeling, and sputtering are iven in the next seven chapters. Each resentation, written y an expert in the area, consists of a rief introduction to the principles of the technique, a discussion of the ractical aspeds of a lying the technique, and a selection of d k r a t i v e examples. &e combination of the individual IBA techniques with microprobe analysis is outlined in Chapter 10, and a comparison of the IBA techniques with other instrumental methods is iven in Cha ter 11. Especially helpful for ra id and easy reference are tEe summaries or hi hlights fountat the end of each major section in the individiual cha ters. In addition, the compilation of reference material in thapters 12-14 will be most useful to both the expert and nonspecialist working with IBA. This affordable volume is an excellent reference source for anyone involved in materials analysis. P I X E A Novel Techni ue for Elemental Analysis by S. A. E. Johansson and J. L. ?!ampbell (A78)appears approximately 2 decades after the technique was first introduced at the Lund Institute of Technology and should quickly become the definitive reference text for PIXE analysis. The first half of the book is devoted to an in-depth treatment of basic principles, equipment, and techniques. Most of this section is directed toward those who already have a degree of familiarity with PIXE. The second half of the book is used for a review of a plications of PIXE in a variety of areas includ biology, mdcine, environmental studies, geol ,and art archaeology. This section is directed toward %se with little or no experience with PIXE but who wish to assess its contribution to and its otential for their own areas of interest. The comprehensive Eibliographies at the end of each chapter will assist any who wish to explore specific aspects in more detail. This moderately expensive volume is an excellent reference source for both the specialist and novice in PIXE analysis. Elemental Analysis of Biological Systems, Vol. 1,authored by G. Venkatesh Iyengar ( A l M ) ,was published in 1989. The first few chapters provide an introduction to the classification and roles of chemical elements in biological systems. Particularly useful for the nonmedically trained researcher is a chapter on the physiological and anatomical features of biomedical sam les. This chapter is an excellent introduction to basic m e d i dterminology, tissue classification, and various characteristics of human tissues. Chapters on sampling techniques, quality control, and the relevance of biological parameters to the presentation and interpretation of trace element data will be especially helpful to the analyst. A brief review of both nuclear and nonnuclear methods of elemental analysis of biological materials includes recommendations on which analytical techniques are best suited for determination of 8 cific elements in biological matrices. Included are tables of ermenta detsctable in different tissue types by N U , PIXE, AAS, ICP-AES, SSMS, electrochemical methods, and direct spectrophotometry. The book concludes with an extensive collection of tables which list reference values for trace elementa in human tissues and body fluids. In spite of its expense, this volume is an excellent reference source for the s cialist in nuclear methods of analysis who wishes to apply t ese techniques to biological matrices. The monograph deservesto be in the library of any institution applying nuclear methods of analysis to biological samples. Hair Anal sis, authored by A. Chatt and S. A. Katz (A54), explores the ih0gica.I basis for, and factors affecting, the trace element contents of hair. The uses of trace element analysis of hair to access nutritional status, identify systemic intoxication, and evaluate environmental exposure are reviewed.

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ANALYTICAL CHEMISTRY, VOL. 62, NO. 12, JUNE 15, 1990

Both nuclear and nonnuclear methods of analysis are briefly described. Discussions on sampling, quality assurance, and the future potential for the use of hair analysis in biomedical research will be most valuable to the analyst. Tables are included which provide elemental concentration values in several hair standard reference materials, normal ranges for trace and minor elements in hair, and age-dependent normal ranges in hair. A valuable comprehensive bibliography is included. Nuclear Analytical Techniques in Medicine, edited by R. Cesareo ( A l l @ ,consists of seven chapters by six different authors. The book is Volume 8 in a series entitled “Techniques and Instrumentation in Analytical Chemistry”. The first chapter by H. J. M. Bowen provides a very brief introduction to the functions of trace elements in biological systems and includes several tables for elemental concentrations in human tissues and fluids. Examples are also given of unusual concentration levels in human tissues and fluids that may be associated with unique diets or special geographical factors. Princi les of photon-induced X-ra fluorescenceanalysis, biome$cal applications of hoton-XRX and some applications of medical tomography gased on the attenuation of X-rays or low-energy y-rays are reviewed in two chapters by R. Cesareo. The principles of PIXE and biomedical applications of this technique are discussed by B. Gonsior. The use of incoherent and coherent scattering of X- and y-rays to measure parameters such as effective atomic number, electronic density, or thickness of a sample and the use of imagin techniques based on Compton scattering are reviewed by E. Gigante. A brief introduction to neutron activation analysis and a number of medical applications of NAA is presented by N. Molho. The final chapter by K. V. Ettinger discusses methods for in vivo nuclear activation analysis. This book provides a ood introduction for the nonspecialist to the nuclear ana&tical techniques and instrumentation that can be applied to biomedical research. It also provides extensive biblio raphies at the end of each chapter for those who may see more detailed information. Unfortunately, the volume is rather expensive for inclusion in a personal library. Isotopes in the Atomic Age by H. J. Arnikar (A126)deals primarily with methods of isotope separation. Among the methods discussed are electromagnetic separation, diffusion, ultracentrifugation, molecular distillation, electrolysis, electromigration, photochemical processes, biological processes, and equilibrium exchange processes. Some of these have had only limited application. Examples and relevant literature references are provided for each of the techniques. Other topics covered include an introduction to the production and major uses of radioisotopes, the characteristics and chemical processing procedures for reactor fuel isotopes, and a discussion of chemical isotope effects. This modestly priced volume would provide good supplementary reading material for students in radiochemistry courses. The Elements of Nuclear Power by D. J. Bennet and J. R. Thomson ( A l l 8 ) is the third edition of a well-established textbook. After two chapters of introductory material on atomic and nuclear structure, the book covers topical matters in the field of nuclear energy. This edition features enhanced treatments of thermal feedback processes and their relation to reactor stability, reactor materials, the nuclear fuel cycle, and reactor safet considerations. Although written principally for advancdundergraduate students in engineering and physics, this book would also be excellent supplementary reading for students in radiochemistry courses. Finally, we note that publication of the two-volume series entitled Activation Analysis, edited by Z. B. Alfassi ( A @ ,is scheduled for December 1989. Examination copies were not available in time to be included in this manuscript. These volumes will be reviewed in our next “Fundamental Review”.

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B. NUCLEAR ACTIVATION METHODS Critical reviews that highlight significant recent advances in the field of neutron activation analysis (NAA) have been published by Ehmann and Vance ( A l l ) ,Heydorn (A12),and Schweikert (A6). These general reviews of the field, and the many more specialized reviews listed in Table I, should be consulted for more detailed treatments than are possible here. 1. Instrumental Thermal Neutron Activation Analysis (INAA). Although publications of applications of INAA are


Reactor Service in Strasbourg (B2)have used a 100-kW Argonaut nuclear reactor with a fast transfer system (=0.4 s) to measure F, Ti, V, Al, Se, and C1 in a variety of geological and biological matrices. A group at the Institute of Atomic Energy Radiochemical Methods in Beijing (B3)has combined two short irradiations and three general A1-7 counting periods to determine 30-36 elements by INAA in Nuclear Activation Methods geological and environmental samples. Koeberl (B4) has methodology discussed both the advantages and disadvanta es of shortA7-20 general and comprehensive irradiation INAA in analysis of samples of eoc emical and A21-23 FNAA cosmochemical interest. Schweitzer et al. b5)discuss preA6, A24, A25 PGNAA cision and accuracy in the use of short-lived delayed activities neutron microprobe A25 for in situ geological analyses. The problem of spatial variCPAA A26-28 ations in the neutron flux density under field conditions is PAA A29, A30 explored. Field determination of A1 with a 252Cfneutron A31-33 RNAA source is also described. Grass et al. (B6)describe the use of preconcentration A32, A33 a “loss-free” counting system and y-ray, Cerenkov, and f or applications neutron detectors for analyses of eological samples, based cosmochemistry A35-37 on counting indicator radionuclifes with half-lives in the environmental A38, A39 subsecond range. Sensitivitie; ?Fe listed for the elements A40-43 geochemistry determined and analyses of several reference standards are industrial processes A44 presented to illustrate decay curve analysis and pulse actiA45-52 materials analysis vation techniques. Pa adopoulos (B7) has described a short electronics A47 irradiation time INAA) analyzer system that employs both high-purity substances A48-51 delayed neutron counting and y-ray spectrometry for the A52 refractory metals determination of U and other elements in samples relevant medicine, life sciences A53-62 to the nuclear safeguards program and in reference material A58-62 in vivo analysis certification. Roth et al. (Ba)have considered flux calibration Isotope Dilution Analysis A63 methods for use in the application of ko factors with short-lived Direct Counting Methods A34, A42, A64, A65 radionuclides. A review by Spyrou (A58) of the use of Ion Beam Analysis short-lived indicator radionuclides for in vivo INAA provides general and comprehensive A7, A18, A66-73 man useful references in this field. Finally, a monograph PIGE A74-76 has teen published, in Russian, by Ivanov and Nikolaenko RBS A45, A77 (AIO) entitled “Activation Analysis Using Short-Lived PIXE A46, A57, A78 Nuclides”. Special sample-transfer facilities and various nuclear reaction analysis A6, A17, A45 com uter programs that are designed to be used for short A79-83 nuclear microprobes irraiations are reviewed later in this section. Transmission, Attenuation, and Scattering A46, A84-89 The utilization of activable stable tracers followed by INAA Methods is an area with considerable tential, but with relatively little Standards for Elemental Analysis A42, A90 current activity. Attas (B9rdiscusses the use of rare-earth Instrumentation element tags followed by INAA to study atmospheric dust general A91, A92 transport, seabed sand movement, and survival rates of automation A93 freshwater fiih. Bromine has been used by Jaspers et al. (BIO) liquid scintillation A94 as an activable tracer for the INAA determination of surface Data Analysis and Computational Methods A95, A96 coverage on solids at the submonomolecular layer level in A97-103 Radioactive Tracers studies of chemically modified surfaces. A new publication A104-107 Isotopic Dating Methods by Whitley et al. ( B I I ) expands on their activable tracer Radioanalytical Applications studies referenced in our 1988 review (AI) by using stable biological A108-110 activable W e and ‘Wu tracers for metabolic studies in babies. environmental Alll-114 Although not actually an INAA approach, it should be noted A115 geochemical that stable lSBDyhas been used by Tsukada et al. (BI2) as an A116 medical activable tracer in chemical yield determinations for separaNuclear Energy A117-120 tions of rare-earth elements from biological materials. Nuclear Waste Management A121-123 Synchrotron Radiation A124,A125 Cyclic INAA (CINAA) has been used by Adesanmi (BI3) A126 for determination of Dy, Sc, Se, Hf, Rb, C1, F, Mn, Al, and Stable Isotope Separation A127. A128 Ca in nine plant species used for teeth brushin in Nigeria. Radiochemical Separations Chatt et al. (BI4) discuss the use of CINAA k r the meaU. S. Radiation Piotection Standards A129 surement of Se contents (via 77mSe)of individual foods and composite diets. Spyrou and Al-Mugrabi (B25) have considered dead-time problems in CINAA associated with the use still numerous, the field is now mature and innovations in the of the large samples required for representative sampling of methodology and instrumentation are few in number. Other some materials. In their procedure, the mass required for techniques, such as inductively coupled plasma mass s ectrometry (ICP-MS), have become very competitive with ~ A A representative sampling is divided into two or more parta and each part is irradiated separately. The measured spectra are for routine multielement analysis a t the trace level. This is then added together for concentration calculations, after apespecially true when there is a need for semiquantitative plying the appropriate individual dead-time corrections. The multielement analyses and in the multielement anal sis of approach is expanded to encompam the determination of what biological samples, where sample dissolution is relative& easy is the minimum representative mam of a sample for elemental (BI). ICP-MS still suffers in comparison to INAA with respect analysis. Other applicationsof CINAA using 14MeV neutrons to its potential for sample contamination during the r uired are reviewed in section B.3. Cyclic techniques applied to sample diasolution, its inherently destructive nature, p 3 l e m s samples sub’ected to preirradiation fractionation procedures with precision (especially in the presence of certain highare reviewed in Section B.7. concentration elements and when variable blanks are encountered), and spectral interferences in the argon plasma due Some other uncommon approaches to INAA are worthy of to the presence of high chloride and sulfate levels, INAA special note. Gunn and Trohidou (BI6) have developed a cannot duplicate the wider range of elements determined with unique surface analysis method they have entitled critical ICP-MS, or its capabih for rapid, in-house analysis, but still reflection activation analysis (CRAA). The activity induced must be regarded as* t e preferred choice for precise and by a beam of neutrons as a function of the angle of reflection accurate multielement analyses of solid samples at the sub is claimed to allow accurate depth profiling of impurities lying microgram per gram level. 1100 A beneath a surface. A wide range of im urity elements An area of renewed interest in INAA is in the use of can be determined. Usmanova et al. (BI7) an anthracene short-lived activities. Researchers at the University Nuclear scintillation detector for P-particle spectrometry for 32Pin the

Table I. Selected Books and Reviews in Radiochemistry, Nuclear Chemistry, and Nuclear Methods of Analysis

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INAA determination of P and S in several metals. Phosphorus and sulfur are distinguished by irradiations with and without Cd filters. Contributions of other &activities are eliminated by using &particle spectrometry. Other interesting detection methods applied to INAA include the use of neutron-induced char ed-particle tracks in materials analysis for B, U, Li, and N (h8), measurement of X-rays resulting from electron capture of internal conversion decay rocesses following neutron activation (B19),and use of mu tiparameter coincidence spectrometry for the INAA of rocks and minerals (B20). A combination of steady-state (250 kW) and pulsed (140 MW) reactor INAA has been used by Ali et al. (B21) for the determination of P b and Sb in ancient glass mummy beads. Lead was determined in both the stead -state and pulsed modes via 800-ms 207mPb,while Sb was dietermined via 93-9 124mSb. Numerous papers have a peared which describe the reactor irradiation facilities availabg for INAA at various laboratories. Fast rabbit systems suitable for INAA with short half-life indicator radionuclides are described by Nagy (B22),Woittiez et al. (B23),Bode and De Bruin (B24),and Dyer et al. (B25). Bode and De Bruin's rabbit system contains no metal parts, only those made of plastic or carbon fiber. The system has resulted in a reduction of rabbit contamination in a reactor fast irradiation facility. The cryogenic irradiation facility at the IRT reactor at the Institute of Physics of the Academy of Sciences of the Georgian SSR is described by Andronikashvili et al. (B26) and applications to the analysis of biomedical samples are presented. Ex riences with the use of the Dalhousie University SLOWPOrE reactor for activation analysis are outlined by Ryan et al. (B27). A robotic sample chan er for use in INAA is described by Thompson et al. (B28). automated y-ray counting and data process' system for the INAA of geological samples has been d e s c r i a by Tanaka et al. (B29). Data on several reference standards are also listed. Niese et al. (B30)have installed a multisample 6- spectrometer in a laboratory that is 47 m underground. The reduced background in this facility allows the determination of Fe in high-purity silicon sam lee by INAA with a detection limit of 40 pg. A programmabye personal computer based multichannel analyzer system has been developed by Kasa and West ha1 (B31) for use in high-count-rate INAA applications. $he system features live-time and real-time correction of counting losses and incorporates sample changer and sample transport controls for use with a short-time activation facility. Advance prediction computer programs (APCP) for INAA continue to receive some attention. Guinn et al. (B32) have ap lied their APCP program to many widely used standard regrence materials and optimum y-ray photopeaks are listed for a variety of irradiation, delay, and counting times. Gwozdz et al. (B33) have developed a simple advance prediction program for the determination of o timal irradiation and delay times and the resulting detection {mits. The latter program was prepared for use with a rsonal computer and is applied s ecificall to the INAA gtermination of elements with sRort-livedf indicator radionuclides. The use of ko factors for absolute neutron activation analysis continues to gain popularity. Values of k factors for 19 nuclides used in reactor INAA have been putlished by Chen et al. (B34)and examples of INAA usin Gent k, factors for the analysis of high-purity quartz glass, f$h-purity Al, As, and zirconia ceramics have been given by rdtmann et al. (B35). A family of computer programs designed to control systematic and random variations in decay curves for the measurement of short-lived indicator radionuclides in INAA has been developed by Schmidt (B36). Nelson (B37) has develo d an INAA program for use with a personal computer whicrhas the capacity for photopeak search, peak area calculation, and element concentration determination using a single comparator method. In the area of correction factors and calibration methods, a number of useful papers have been recently published. Ila (B38) has determined Wyttenbach factors in studies related to correcting for coincidence losses and pulse pileup in INAA of geolo ical samples. Verheijke and Jansen (B39)have determine! characteristic neutron spectrum arameters for the BR1 and BR2 reactors at Mol, Belgium, tRe HFR facility at Petten, Netherlands, and the FRJ2 reactor at Julich, FRG. Burgess (B40) has developed a target factor analysis (TFA) method for analysis y-ray spectra obtained in INAA. The

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method is based on the use of all the information contained in single-isotopespectra, rather than the conventional use of only selected full ener peaks which must then be separated from the base line anyany overlapping peaks. The method is a type of multivariate analysis in which information concerning contributing factors is gathered from the observed experimental composite of factors, which in this case is the INAA y-ray spectrum. It is noted that an extensive library of spectra is required for use of this method, but this is now not beyond the capability of many microcomputers. Several test cases are resented. It is stated that the chief utilization of TFA w o d b e in facilities where large numbers of similar samples must be routinely analyzed or in preconcentration and group separation methods where the nuclide library can be more limited. Korotev (B41) notes that commercial aluminum foil may contain up to 1.4 pg of U/g of foil. Samples or sample vials in contact with the foil can be contaminated with recoil-implanted fission products of the in the foil. Corrections in the determination of Zr, Mo, La, Ce, and Nd by INAA may be required. In another paper dealing with the potential for U fmion product interferences in INAA, Gouveia et al. (B42) have reported a numerical procedure to correct for interferences to the determination of li ht rare earths, Zr, and Ru in rocks and minerals. Kuchava ( j 4 3 ) has examined loss in sample weight of biological specimens irradiated in both cooled and noncooled reactor irradiation channels. For unsealed samples, weight loss can be significant and calculations based only on postirradiation weights may be in error. Techniques for the preparation and use of primary standards in activation analysis have been reviewed by Becker (B44). It is suggested that natural matrix standard reference materials be used only as quality assessment materials, rather than as comparator standards for INAA. Quality assessment of the routine INAA system for analysis of geological sam les at the Interfaculty Reactor Institute (IRI) in Delft, Netierlands, has been discussed by Bode and Van Meerten (B45). Routinely, 40-45 elements are determined with adequate accuracy. Several recent papers have combined INAA with other analytical techniques to either extend the range of determinations or merely critically compare the methods. In a review article, Watterson (A181 compares neutron activation analysis (NAA) to ion beam analysis (IBA) for a wide range of Sam le types and concludes NAA is the more mature methot but the special capabilities of IBA in the areas of surface composition and spatial distribution may result in unique future applications. INAA and atomic absor tion spectro hotometry were compared by Danbara et al. b 4 6 ) for the letermination of trace elements in grass. It was noted that the techniques yielded different values for Mn and Fe but agreed satisfactorily for many other elements. Finally, Ismail et al. (B47)combined Miissbauer spectroscopy, INAA utilizing a fast sample transfer system, and a high-rate y spectrometer to determine Sc, Ti, Hf, Al, V, Mn, Dy, Se, Cu, and the different oxidation and spin states of Fe in environmental samples. Selected publications illustratin recent applications of INAA are presented in Table 11. !'he listing is not meant to be exhaustive but should at least provide the reader with key references that will facilitate further literature searches. In many applications more than one type of activation analysis is used. We have attempted to place the citations under headings that are most representative of the work described and have provided cross-referencing for those cases where the multimethod approach is unique. 2. Reactor Fast Neuton and Epithermal Neutron Activation Analysis (ENAA). The influence of multiple irradiation filters in ENAA is considered by Skarnemark et al. ( B I B ) . Filters of W and Na of different thicknesses were used to reduce the resonance neutron capture interferences caused by these two elements in the analysis of eological samples. Improvements in detection sensitivities a n f precwion were observed for Sc, Fe, Co, La, Sm, Eu, Gd, Tb, Yb, Lu, Th, and W. Other ap lications of filtered e ithermal neutron activation analysis (FgNA) are proposed. &hela and Gawlik (B129) have explored the use of Hf irradiation filters for reactor fast neutron activation analysis. Fast neutron reactions may be advantageous when the (n*,y) reaction roduct has unfavorable nuclear properties or is simultaneouiy roduced by an interfering reaction. An example cited is tRe determination of P by the 31P(n,a)28A1 reaction in the presence of


Table 11. Selected Applications of Instrumental Thermal Neutron Activation Analysis Archaeology bone ceramics, pottery coins and metals data banks glass pigments rocks, sediments, soils Environmental and Agricultural Science animals atmospheric, dust foods and diets general applications trees and plants Forensics bullet lead general Geology, Geochemistry and Cosmochemistry borehole analysis cosmochemistry, meteorites fossil fuels and byproducts general ores and minerals rocks, rock systems sediments Industrial Products and Related Applications coatings electronics general glasses high purity materials metals Medicine, Human Tissue blood and blood components bone brain cervix

eye general hair and nail in vivo liver

muscle teeth Other film badge dosimetry general INAA material exposed to the Nagasaki bomb nuclear safeguards use of isotopic neutron sources

B48 B49-51 B52-54 B55 B21, B56, B57 B58 B59-61 B9, B62-64 A13, B6, B47, B138 B11, B14, B65-70 A14, A20, A39, A l l l , B3 B13, B46, B71-75, A39 B76 A5 B77, B78 A35-37, B4 A13, B8, B66, B79-81 A14, A40-43, A115. B6, B45 B82-89, B127, B137 . B3-6, B20, B29, B42, B60, B61, B90-96, B99, B125 B9, B59, B93, B97-99 BlOO A47

A14, A44 B18, BlOl A48-50, B30, B102, B103 A52, B17, B18, B104, B126 B43, B105-109 B48, B110, B l l l B112-113 B114 B115 A14, A16, A55-57, A116, B26, B108 A53-54, B116-120 A58-62 B121 B122 B123 B124 A6, AS, A l l , A12 B125 B7 B5, B78, B82, B84, B87, B126, B127

Al which yields the same indicator radionuclide by the ( n ~ , y ) reaction. The possibility of using multiple irradiation filters is also discussed. Discussions of the ko-factor method which relate to its potential use in ENAA have been resented by Elnimr et al. (B130) and Jovanovic et al. (E131f: The single comparator method used in INAA has been extended by Verheijke and Jansen (B132) to reactor fast neutron reactions, based on studies of (n,p) reactions on Ti and Ni. ENAA facilities a t the TRIGA MARK I1 reactor in Ljubl'ana, Yugoslavia, have been described by Jovanovic et al. ($133). Other ENAA facilities at the University of Virginia are described by Williamson et al. (B134). In the latter publication, examples are given for the determination of I in infant formula, as well as Si, Ni, Zr, U, and Th in a wide variety of matrices. In other selected applications of ENAA, Mg, Al, Cu,P, and Mn have been determined in blood serum Cr, Ni, and As in and commercial milk by Lavi et al. (B135);

lun tissue and urine b Landsberger and Simsons (B136); As,%o,Eu, Fe, Ga, La, Sb, Sc, Sm, U, and W in phosphate rocks by Zaghloul et al. (B137); indium in air pollution sam-

d,

(B138); and a variety of elements in geological 3. Prompt y Neutron Activation Analysis (PGNAA). Chen (B140) has described a mobile nuclear reactor for use in in vivo PGNAA. The system, which can be moved where it is needed, has a neutron beam tube with a shutter, neutron and y-ray shielding, and biological sample and detector mounts. Data for the detection limit of Cd in rata are presented. Isotopic neutron sources are also commonly used in PGNAA. Wu et al. (B141) have developed a PGNAA system using paraffin-moderated neutrons from 241Am-Be sources together with a Ge(Li) detector. An interesting publication by Kacperek (B142) describes the use of fast neutron pulses for dose reduction in in vivo PGNAA. A portion of the neutron "burst" is switched off for the period when the ADC is busy processing a y-ray pulse. Hence, a decreased neutron dose to the patient is achieved. The technique is illustrated by the measurement of Mg in a bone phantom. The optimization of nuclear reactor beams for PGNAA applications in biomedical research has been studied by Borisov et al. (B143). The matrix-dependent shape variability of the Doppler-broadened y-ray line resulting from PGNAA of B has been investigated by Hofmeyr (B144). Corrections based on the symmetry of the line are especially significant in cases where there is an interference from Na. The most common ap lication of PGNAA is in vivo analyais. Chung and Yuan b14)describe the use of a mobile nuclear reactor to determine Ca, C1, N, and P in a water phantom containing internal organs and legs. Optimum irradiation source-to-subject distance for body irradiations with a 23Bpu-Be neutron source are considered by Ebifegha (B146). Underwood and Petler (B147) have used both a 241Am-Be neutron source and a 14-MeV neutron generator coupled with a Ge y-ray detector to measure induced y-ray response in borehole logging for coal. Other recent applications of in situ or on-line analysis in the coal industry have been described by Eisler et al. (B148),Goeldner et al. (B149), Senftle and Mikesell (B150),and Chrusciel et al. (B151). Other geological applications of PGNAA are described by Avinc (B152), He Schweitzer e 3 (A89), Olivier et al. (B153), Pinault (B78), (B154), and Tittle and Glascock (B155). Chung and Tseng (B156) have used a 262Cfsource and Ge detector probe to determine B, Cd, C1, Cr, Cu, Fe, Hg, and Mn in seawater by PGNAA. Zeisler et al. (B64) used X-ray fluorescence, PGNAA, and INAA to determine 44 elements in marine bivalve material. Comparisons of PGNAA with other nuclear methods of analysis are presented by Hnatowicz (An. Stone (B157) has discussed the advantages associated with the use of cold neutron beams in PGNAA, rather than normal reactor thermal neutrons. Additional applications may be found in review articles listed in Table I (A59-61). Some PGNAA applications using 14-MeV neutrons are considered in section B.4 of this review. 4. Accelerator Fast Neutron Activation Analysis (FNAA). The development of new hi h-yield particle accelerator neutron generators has s ar ed new interest in FNAA. Most neutron generators stii rely on the 3H(d,n)4He fusion reaction to produce 14.7-MeV neutrons. However, as noted below, other nuclear reactions may also be employed. One of the most promisin advances in the instrumentation of this field (B158) is the ievelopment of the Karlsruhe ring ion source neutron generator (KARIN). This machine consists of a sealed hi h-power, high-voltage as discharge accelerator tube designef for production of 14-hfeV neutrons by the D-T reaction. Ions are produced in a eri heral ring ion source at low pressure and are acceleraterfantf focused to the center of the ring where they impinge on a coaxial solid ScDT metal hydride target mounted on a water-cooled electrode. The KARIN tube rototype is claimed to have a total neutron yield of 5 X 10l2n 6 and a minimum operational life of 300 h. In addition to its use in FNAA, the KARIN tube has been used for medical neutron radi aphy. A proposed Karlsruhe target ring neutron generator ( E T R I N ) with an anticipated source strength of 1014n/s is also discussed. Andreev et al. (B159) described production of neutrons for FNAA by accelerating a variety of charged particles to 400-500 keV in a T-400

f


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termination of C, N, and 0 has been reviewed by Nozaki neutron generator. They note that the machine can also be (I3178). used for nuclear micro robe analysis, PIXE, and X-ray The excitation functions for the CPAA reactions IZCfluorescence analysis. dayton and S ackman (B160)have (3He,~)1iC and 12C(3He,d)i3Nwere measured in the ener used an electron linac with W-U a n t W-Be targets and a reson between 0.4 and 14.0 MeV by Liebler et al. (B179). moderator to produce a thermal neutron flux density of =loio n cm-2 s-l over 2-3 kg rock samples. The linac may also precision of the absolute cross sections deduced from these measurements is 10%. Friedli and co-workers have continued accelerate protons and produce a variable-energy fast neutron to investigate the use of heavy-ion beams in CPAA. In ref yield of >loi2n/s using the %i(p,n)'Be reaction. By selection B180 they report that in addition to the very sensitive deof appropriate incident proton energies, problems associated with interference reactions can be minimized. Determinations tection of B and N, a $Be beam of the a propriate incident can be used for the multielement &termination of Na, of Au and 236Uare discussed. Watterson et al. (B161)have a Sc, and Zn. In ref B181 they note that a liB beam can used the gBe(p,n)gBreaction to produce energetic neutrons re , ?i be used to sensitively determine Li, Be, Mg, and Si, and in for activation of isomeric states in Au, Er, Ir, and Y, to induce ref B182 they demonstrate the viability of using a I5N beam (n,p) reactions on A1 and Si, and to activate A1 b the (n,y) reaction. Optimum analytical parameters were etermined for the determination of trace amounts of Li, Be, and Mg. The by varying proton ener 'es from 4 to 10 MeV by using an EN ion beams in the latter two studies (B181-182)were used to measure Li, Be, and B in glass samples and to determine the tandem accelerator a n 8 a 1-mm-thick Be target. It is noted Mg content in various types of alumina. that optimum determination of Au in rocks was obtained with =5 MeV protons. A review of the advantages of FNAA which A survey of the literature indicates that the most frequent includes a useful table of y-ray ener ies of radionuclides application of CPAA in the last 2 years has been in the analysis produced by 14-MeV neutron-induce8 reactions has been of semiconductor materials (B183-193).This is most likely published by McKlveen (A21). due to the fact that CPAA is ideally suited for the determination of the light elements B, C, N, 0,and P, which are, mmt Cyclic 14-MeV neutron activation analysis and the meaoften, the ma'or residual impurities found in semiconductor surement short-lived indicator radionuclides are described in materials. The electronic properties of semiconductor maa series of publications by Kondo (B162-164)and a publication terials are, in large part, governed by these residual impurities. by Pepelnik (B165).Pepelnik notes that more than 30 eleRoutine methods for both the instrumental and chemical ments having indicator radionuclides with half-lives less than application of CPAA to semiconductor materials are given in 1 min can be determined with sensitivities below 50 pg by refs B183, B185, and B186. Comparisons of CPAA with other using a high-intensity neutron generator with a 14-MeV analytical techniques and discussions of the accuracy and neutron flux density of 3 X loio n cm-2 s-l. Applications of reliability of CPAA semiconductor analysis can be found in FNAA for the analysis of soils, sediments, metals, and atrefs B183 and B192. Both Maggiore et al. (B191)and Blonmospheric particulates are presented. The use of X-ray diaux et al. (B193)describe the combination of CPAA with spectrometr after 14-MeV neutron activation has been dechanneling for determining the lattice site occupied by the scribed in puhications b Barouni and co-workers (B166-168). light impurities B, C, and 0 in GaAlAs and GaAs. Similarly, Determinations of Br, %, and Sb are used to illustrate the Krauskopf et al. (B190)describe the combination of CPAA approach. Fast neutrons produced by bombarding a thick Be with nuclear reaction analysis to measure the B, C, and 0 target with 53-MeV deuterons were used by Krivan et al. content and to determine the C depth profile in GaAs. (B169 to determine P in high-purity materials via the 31P(n, )3 Si reaction. Following irradiation, the 31Siwas chemIn other applications, CPAA has been used in the analysis iAy separated as SiF4,and the @-activitywas measured with of motor oil (B194),coal (B195),high-T, superconductors (B196, B197,B189),metallurgical samples (B198, B199),bia liquid scintillation counter. A detection limit of 3 ng of P/g is claimed. Gordon et al. (B170)have developed a new nuclear ological samples (B75,B200,B201),environmental samples (B195), and eological samples (B202).In an unique approach, method for three-dimensional analysis of solid materials. The Pillay et al. b203)have combined charged-particle activation technique is based on use of a neutron diagnostic probe (NDP) analysis with delayed X-ray emission for the analysis of ore that consisted of a combination of a sealed-tube neutron generator using the D-T reaction, an internal a-counter for samples containing the platinum-group elements. Although associated- article neutron time-of-flight spectroscopy, and the detection limits for the six platinum-grou elements achieved with this technique are only comparabre to PIXE a detector &r inelastic y-ray spectroscopy. The method has been applied to the analysis of corrosive agents on turbine and INAA, this approach has the advantage in that all six elements are visible and interference free in a single, simple blades, bulk analysis of coal, oil shale, and sandstone, and the spectrum. detection of concealed explosives or contraband. A useful 6. Photon Activation Analysis (PAA). As was the case com ilation of 14-MeV activation cross sections has been in our previous review (AI),few new publications on the pubEshed by Pepelnik (A22). The latter publication also presents data obtained by FNAA of sediment samples from methodolo y of PAA have appeared in the literature. This the Elbe river. Other recent applications of FNAA include is most pro%ablydue to the fact that few analysts have access copper coins to the high-intensity photon sources required for the techanalysis of coal by Underwood and Petler (B147), alloys by Vorsatz and artifacts b Beauchesne et al. (B171), nique. An overview of the a plications of hotonuclear reand Zemplen-Jap (A23), plant materials and fertilizer by actions to activation analysis [as been publis\ed by Segebade et al. (A29).In addition, Khristov et al. (A30)have reviewed the protein content of soya beans Wasek and SterlinsL (B172), via N determination by Szegedi et al. (B173), bulk elements the use of their microtron for y-ray activation with special the C/O in materials in an on-line system by Gozani (A88), emphasis on the analysis of geological and biological samples. and ratio in borehole analysis by Roscoe and Grau (Bl74), The effect of the instability of the electron accelerator oxygen in superconductors by Arnett et al. (B175)and suenergy on the error in y-activation analysis was investi ated perconductor starting materials by Hamrin et al. (Bl76).In bz Davydov et al. f3204).The three reactions "Cu(y,nb2Cu, the latter paper, the im ortance of knowing the oxygen O(y,n)150,and ' A ~ ( y , y ' ) ~ ~ ' ~ were A u studied and the restoichiometry in supercondlcttor starting materials is stressed. lationship between the relative mean-square error of the Often, drying commerciallyavailable high-purity metal oxides analytical signal and the accelerator energy was derived. at conventional 110 "C drying oven temperatures is not adOne interesting application of PAA has been the developequate to achieve the stoichiometry for the compound that ment of an activation method for the investigation of the y-ray is stated in the provided assay. fields found around stored spent fuel assemblies. Lakosi et ai. (B205)report that the fission product and transuranium 5. Charged-Particle Activation Analysis (CPAA). The content of irradiated fuel can be traced by using '151n as a increased number of compact, variable-energy accelerators in target material for both y-ray and neutron activations. *non-nuclear" laboratories has made activation analysis with Moreover, the hard y-ray component of the radiation field charged particles a more readily available analytical technique. can be analyzed by use of the (y,n) conversion reactions on General reviews of CPAA have been published by Hnatowicz Be or D targets. (A77 and Vandecasteele (A26). Hoste et al. (A27)and Nozaki (Bl77)have reviewed the application of CPAA for the deIn other applications, Schelhorn et al. (B206)describe a termination of light elements in metals and semiconductor chemical separation method for the determination of F in eological samples on the basis of the lgF(y,n)18Freaction. materials and Szabo (A28)has reviewed the application of Eat0 et al. (B207)report the use of a low-energy photon CPAA to food analysis. The accuracy of CPAA for the de-

&

d

56R

*



spectrometer in con’unction with instrumental PAA to determine Ni, Zn,Br, db, Zr,Mo, Cd, and Pb in human kidneys and livers. And last1 , Schulze et al. (B208)describe the use of PAA for the a n d s i s of trace elements in a variety of buildin materials. d e y note that, in most cases, PAA yields minim3 detectable limits that are lower than those that can be achieved with energy-dispersiveX-ray fluoreacence analysis. 7. Radiochemical Neutron Activation Analysis (RNAA) and Preconcentration Methods. In accordance preirrawith a trend we noted in our previous review (AI), diation elemental concentration or molecular fractionation methods have received considerable recent attention. In cases where single element or grou separations are employed prior to irradiation the approac is commonly referred to as chemical neutron activation analysis (CNAA). If chemical speciation (often by bioanalytical methods) is involved in the preirradiation separation, the a roach is called molecular neutron activation analysis ( M N R ) . &in (A33)has reviewed advances in the reconcentration of trace elements for NAA. Freeze-dryi afso tion, extraction, coprecipitation,and f i e assay meth s are escribed and 60 references are provided. Another review b Tomura (A32) provides 79 references relating to preirradilation preconcentration and conventional postirradiation radiochemical se arations. Danesi (B209)has reported the use of supporte liquid membranes for the separation and concentration of metal ions from environmental and metallurgical samples. Preirradiation separation of chemical species (MNAA) combined with conventional INAA has been used by Blotcky et al. (B210)for deternation of total Se, trimethylselenonium ion, and selenite ion in Fine and serum. Jayawickreme and Chatt (B211)combine a vanety of bioanalytical techniques followed by INAA and CINAA to determine up to 29 elements in fractions of biological tissue. Among the reirradiation separation techniques em lo ed are ultracentri ugation, dialysis, fractionation by (k&)zs04 precipitation, gel filtration on Sephadex G-150gel, ion-exchange chromatography, electrofocusing, chromatofocusing, hydrox lapatite chroma aphy, and isotachophoresis. Stone et al. ($1212)have used PO yacrylamide gel electrophoresisand NAA for the determination of proteins, using phosphoproteins and phosphoprotein-containin matrices as examples. The approach has also been applie to Se-containing macromolecules. Pretreatment or preconcentration methods have also been used for eological samples. King et al. (B213)have removed B from Efrich minerals by a volatilization technique to avoid neutron-flux su ression in analyses for rare-earth elements (REE). Preirrac iation r group separations of REE in geological samples have been re orted by Das (B214),Terakado et al. (B215),and Zhou a n i Gao (B216). Fire assay methods of concentrating Au and Pt-group elements prior to NAA have been described by Hoffman (B217),Parry et al. (B218,B2191, and Shazali et al. (B220).A preirradiation se aration of trace elements from the Ta matrix has been used gy Caletka et al. (B221)in the analysis of Ta materials. Procedures for the chemical pretreatment of natural waters or sewage to concentrate trace elements have been published b Laul et al. (B222)and Zmijewska et al. (B223). Yeh andrco-workers (B224)have reported the use of hydrous MgO for both preconcentration and RNAA. The adsorption properties of 47 - ions are described. In the area of conventional RNAA, Byrne and Krasovec (B225)have used radioactive WOtracer to determine the chemical yields for Co separation in the RNAA of biological snecimens for Ni content via the 68Ni(n.D)68Coreactor fast &&on reaction. Cobalt is simultaneo~lfdetermined by the 5gCo(n,y)60Coreaction. The use of radioactive tracers for chemical yield determinations in RNAA is also discussed by Schelhorn and Geisler (B226). The ap roach is illustrated by data obtained for Cu in biological an$ geological standard reference materials. Selected applications of both pre- and postirradiation chemical separations in NAA are presented in Table 111.

R

3 r

B

P

7

J

C. ISOTOPE DILUTION ANALYSIS (IDA) The techniques of radioimmunoassay (RIA) and radioreceptor analysis (RRA) are still the most common applications of IDA. Consideration of the extensive literature associated with these techniques is, however, beyond the scope of this review, and we direct the reader interested in these techniques

to the reviews found in refs C1-5. Similarly, we have chosen not to review the literature dealing with stable-isotopedilution analysis as this technique is covered in detail in the ”Atomic Mass Spectrometry” review in this issue. Progress in the substoichiometric method of isotope dilution analysis (SSE-IDA) has been reviewed by Kyrs (A63).Variants of the substoichiometric technique are tabulated and some problems of using the substoichiometry principle are discussed. A new technique that couples IDA to high-performance liquid chromatography (HPLC) has been described by Banerjee (C6). In this approach, the difference between the retention of injected analyte and that of isotopically labeled analyte which is in equilibrium on the column is used to induce isotope dilution. The advantage of this combined approach is the same as that of the SSE-IDA method; it removes the need for a direct measurement of the analyte mass and hence can greatly improve the sensitivity of a classical IDA measurement. And finally, as an example of the usefulness of the classical IDA technique, we mention the study by Sah et al. (C7) in which two new IDA procedures were developed to measure nitrogen fixation. The methods were compared with the traditional lSN2gas IDA procedures and difference methods for measuring nitrogen fixation and it was found that the new IDA approaches were simpler, relatively inexpensive, subject to fewer errors, and applicable to a wider range of conditions. Moreover, the accuracy of the new IDA procedures was found to be comparable to the 15N2-gasIDA measurement.

D. DIRECT COUNTING OF NATURAL AND LONG-LIVED RADIONUCLIDES The counting of naturally occurring and other long-lived radionuclides continues to be important in a number of special applications (A34).These applications, which occur in fields as varied as environmental chemistry and nuclear safeguards, typically involve a counting of actinides or y-ray spectroscopy for lighter radionuclides. Liquid scintillation counting is used for the determination of tritium and 14Cprimarilgobut special techni ues for counting radionuclides such as P b by this met&? have been reported (01). Myasoedov and Pavlotskaya (A64)have considered the sources of pollution by natural and technogenic radionuclides, while Yu (02)has noted that there are approximately 200 radionuclides that should be monitored regularly for health reasons and has discussed the accuracy of their measurement. Despres (03)has presented the results of interlaboratory comparisons of low-level radioactivity measurements in France. The reported deviations from for a restricted number of laboreference values were -3% ratories and 3-10% for the majority of others. Procedures for preconcentration and measurement of cosmo enic 7Be in natural waters have been described by Kostatinov et al. (04),and methods for the low-level determination of q c in the environment have also been published (05,06). Livens and Quarmby (07) have examined sources of variation in environmental radiochemical analysis. y R a y spectroscopy has found geochemical application in measurements of the changes in radioactivity of phosphate rocks during processing (08) and for examining core samples for the determination of characteristic chemical values of carbonate clay raw materials (09). The different radioanalytical methods presently used for actinide determination, with particular emphasis on the determination of low levels of a-emitters, have been reviewed (A&). Singh and Wrenn (010) have summarized the radiochemical procedures used in their laboratories for the determination of actinides in biological and environmental samples. A number of interesting developments and applications for the countin of actinides have been reported. Spezzano and Silvestri (b11)have described a radipchemical procedure for the determination of a-emitting nuclides of Th and U in soil and sediment samples, while Arslanov et al. (012) have developed a method for the simultaneous determination of the 238U,234U,232Th,and 23”Thin Fe-Mn concretions. A radiochemical method for the simultaneous determination of Pu and Am in biol ical and environmental samples has been reported (0135 a$ the analysis of large volume samples of seawater for +Np by radiochemical preconcentration and subsequent a-spectroscopy has been performed successfully (014).Orr (015)has evaluated different counting methods ANALYTICAL CHEMISTRY, VOL. 62, NO. 12, JUNE 15, 1990

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Table 111. Selected Applications of NAA Using Pre- o r Postirradiation Chemical Separations matrix

elemenb determined

methodology

refs

Biological/Medical Samples blood and blood components Cr Cr Se Ag, Co, Cr, Cs, Fe, Hg, Rb, Sb, Sc, Se, Sn, Sr, Zn As, Au, Cd, Cs, Cu, Hg, Mo, Rb, Se, Zn many Al, Cu, Mg, Mn, P general As, Mo, Sb, Se hair HK A i Cd, Cu, Hg, Zn human diet, foods As, Hg, Sb, Se U. Th c l , Zn, ~a many internal organs As, Cd, Cu, Hg, Zn As, Hg, Sb, Se many Pt Ag, As, Mo, Cr, Sb, Se, Sn proteins Se standard reference materials U Ni, Co cu urine Se and Se species

RNAA RNAA, liq/liq extr RNAA, liq/liq extr RNAA, group sepns using acid A1203,hydrated Sb205and Mn02

B227 B228 B229 B230

RNAA, ion exch

B231

RNAA and INAA RNAA and INAA, SbzO5 RNAA, liq/liq extr RNAA RNAA, liq/liq extr RNAA, silica gel and activated carbon columns CNAA RNAA, SbZOb RNAA and INAA RNAA, liq/liq RNAA, silica gel and activated carbon columns CNAA and INAA RNAA RNAA, liq/liq extr and inorg ion exch CNAA RNAA, liq/liq extr and anion exch RNAA, anion exch RNAA, radioreagent method molecular NAA, ion exch

B107 B135 B232 B233 B234, B235 B236 B14 B67 B68 B234, B235 B236 B211 B237 B121 B212 B238 B225 B226 B210

Environmental Samples plants and misc water

RNAA radiochemical displacement of @To CNAA and RNAA CNAA, ion exch and coprecipitation

B239 B240 B222 B223

Geological Samples and Meteorites meteorites rocks and minerals

many &Mn noble metals

REE

CNAA, selective dissolution of mineral phases RNAA RNAA, chelating resins and amine solv extr RNAA, coprecipitation and ion exch CNAA, Pb fire-assay CNAA, Ni-NiS fire-assay CNAA, TeS2 fire-assay RNAA, oxalate precipitation CNAA and RNAA RNAA, ion exch CNAA, B volatilization CNAA, ion exch and coprecipitation CNAA, cation exch CNAA, liq/liq extr and ion exch RNAA and INAA

B241 B242 B243 B244 B217 B218, B219 B220 B245 B246 B247 B213 B214 B215 B216 B248

Industrial Samples metals

semiconductor materials

many in A1 many in various metals U, Th, others in Mo Si in high-purity metals manv in Ta U, f h

RNAA, Sbz05, ion exch and liq/liq extr liq/liq extr and ion exch cation and anion exch RNAA, distillation of SiF, CNAA, liq/liq extr and ion exch RNAA. ion exch

for oceanic zzaRaand has suggested ways by which the analytical recision can be improved over that of conventional metho&. In our most recent review ( A I ) ,we neglected to mention an a-radiometric analysis method which provides an attractive alternative to conventional counting methods. In this method (see, for example, ref D16),liquid scintillation a-spectrometry, with electronic rejection of B and y scintillations, is employed after initial chemistry, typically liquid-liquid extraction. With the appropriate sample-preparation chemistry, all a-emitting radionuclides in a sample can be rapidly determined. E. ION BEAM ANALYSIS Elemental analysis with ion-beam-induced nuclear reactions has continued to emerge as one of the most fruitful applica58R


B249 B250 B251 B169, B199 B221 B252

tions of nuclear methodolo It is clear from the multitude of applications listed in Tages IV-VI1 that these techniques have moved out of the realm of the specialized “nuclear” laboratory and have found widespread use among researchers in many different areas. Our informal survey indicates that, since our last review, there has been a remarkable increase in the number of small accelerators that are dedicated solely t o ion beam analysis. Most notable of these is, perhaps, the 2-MeV NEC tandem Pelletron accelerator that has recently been installed inside the Louvre Museum for the sole purpose of applying TSA techniques to museum problems. Naturally, the amount of literature in the field has grown along with the increased interest in and usage of IBA techniques. Yet, because the field has “matured”, the majority of the publications now focus on the applications of ion beam analysis and the


literature clearly reflects the fact that the advances in methodology are occurring more grudgingly. In this review we have arbitrarily divided ion beam analysis into three general categories-PIGE, RBS, and other nuclear reaction analysis (NRA)techniques. The divisions are simply for convenience as all three of these techniques are based upon ion-beam-induced nuclear reactions and as all three are frequently employed simultaneous1 . In fact, the last portion of this section deals with the corngination of these three IBA techniques with nuclear microprobea. Since the nature of most ion beam analyses depends critically on the specific problem and type of material that is to be characterized, we have grouped the references to IBA techni ues in Tables IV-VI1 according to application. Particle-inluced X-ray emission (PIXE) and low-energy IBA techniques such as low-energy ion scattering and s uttering have not been included in this review because (1) $though these analytical methods do use accelerated ion beams, they do not involve nuclear reactions and (2) these techniques are adequately reviewed elsewhere. The one exception to this is that PIXE is included in this review when it is used in conjunction with PIGE, RBS, and other NRA techniques. 1. Particle-Induced y R a y Emission (PIGE). This techni ue, which is also occasionally referred to as PIGME or PIP%% analysis, is based upon the detection of the prompt y-rays that are emitted following a charged- article-induced nuclear reaction. It is most frequently usefin the analysis of the light elements which cannot be readily determined with PME or XRF. Because PIGE is based upon nuclear reactions, it can be used to identify different isotopes. An excellent introduction to and review of this technique can be found in the volume edited by Bird and Williams (A66). For the application of PIGE to the analysis of thin and intermediate sam les of unknown composition,Boni et al. ( E l ) have measured t e differential cross sections of the proton prompt-y reactions on Li, B, F, Mg, Al, Si, and P. The cross sections were measured in the beam energy range of 2.2-3.8 MeV in intervals of 20 keV. In the a plication of PIGE to thick tar et analysis, Olivier et al. have carefully investigate! the effect that added analyte used in spikin has u on the proton ranges in the unknown sample. Simifarly, dorland et al. (E3) have examined how molecular effects influence the proton range corrections used in the quantitative calculations. A unique approach to the PIGE analysis of thin and intermediate samples has been developed by Boni et al. (E4, E5). In order to compensate for the strong energy dependence of the prompt-y reaction yields in these samples, they have constructed a system that provides an energy-spread proton beam with a rectangular energy distribution. The system simp1 consists of a rotatin A1 diffuser disk whose sectors have Jifferent thicknesses. bhis approach was tested on the NBS-1648urban particulate matter standard and is now used, in conjunction with PIXE, for the routine analysis of urban aerosol samples. Two other novel a roaches are noted here. Mingay et al. (E61 have use pulsetf!eams in PIGE analysis to reduce the background and hence improve the sensitivity of the measurements. Improvement factors typically between 2 and 5 were achieved, and the technique was found to be particularly useful for higher energy reaction anal where beam-induced radioactivity leads to high detector gkgrounds. Peisach et al. (Enhave investi ated the viability of using low-energy photons (20-200 ke$) in PIGE analysis. This techni ue, as one would anticipate, was found to be most readily apdicable to the determination of transition metals. One area in which PIGE has emerged as an especially useful technique is in nondestructive de th-profiling analysis. Both Liao et al. (E8)and Barit et al. (&I describe the use of PIGE to determine the 16Ndepth profiles in metal samples. Likewise, Kuzmin (A76) reviews the use of the 15N(p,ay)12C, nAl(p,y)28Si, and 1gF(ppy)160reactions to depth profile 15N in GaAs and A1 and F in Si0 And, as a final example, the prom t-y-rays emitted in the &16N,a.y)1PCreaction have been usedy! Ji et al. (ElO)to measure the water penetration in sodium-@-alumina. These and other applications of PIGE analyses are listed in Table IV. 2. Rutherford Backscattering Spectroscopy (RBS). Elastic scattering of charged particles has emerged as a powerful tool for studying the stoichiometry, structure,

Table IV. Selected Applications of PIGE and PIGE/PIXE Analysis

PIGE Analysis biology and medicine human placentas environmental science urban aerosol aerosol sulfur geology Cr in standard ore Si, Al, and Na in zeolites material science alloys in Au matrix N depth profiles in steel N depth profiles in GaAs and Ti AI and F depth profiles in SiOz H20 penetration in alumina miscellaneous F in tea leaves

.

E4 E12 E2 E13 E7 E8 A76, E9 A76 E10 E14

PIGE/PIXE Analysis archaeology stone artifacts biology and medicine human placentas stable isotope tracers in cells biological Fe mineralization environmental science waste-water treatment process geological zeolites miscellaneous trace elements in milk

R

(k!)

Ell

E15 E16 E17 E18 E19 E20 E21

Table V. Selected Applications of Rutherford Backscattering Spectroscopy

alloys biology and medicine ceramics electronic materials glasses ion-implanted materials Gds

iron nickel silicon steel titanium multilayered materials oxides semiconductors superconductors thin films inorganic compounds polymers pure elements miscellaneous catalysts high-energy ion sputtering labradorite crystals lithium niobate waveguides solar cells X-ray mirrors zeolites

E36, E43, E44 A71, E45, E46 E47-49 E26, E50, E51 E25 E52 E53 E52 E41, E54 E55 E53 E56-58 E5941 E27, E62-66 E39, E67-70 E71-73 E74 E75, E76 E77 E78 E79 E80 E81 E82 E83

thickness, and impurity concentrations of surfaces. In fact, RBS is now in such widespread use by solid-state physicists and material scientists that it is usually considered along with other routine surface analysis techniques. Reviews describing this technique abound (A#, AM-71, A77, E21-30). Specific applications of RBS (and ERD) analysis are listed in Table

v.

The experimental apparatus used for RBS analysis can be of widely var ing degrees of complexity. Norton et al. (E31) describe a f d y automated RBS spectrometer system in which it is possible to analyze up t o 100 samples per batch for ANALYTICAL CHEMISTRY, VOL. 62, NO. 12, JUNE 15, 1990

59R


random orientation, rotatin random, or channeling analyses. The new system describedty Van Oosterhout (E32) will be of special interest to the researcher involved in ion-implantation work. This recently developed accelerator system provides highly collimated mass-analyzed ion beams in the low-energy range (100 keV) needed for ion implantation and the high-energy range suitable for RBS analysis (1-2 MeV). We would also mention here the multidetector system of Guenzler et al. (E33). This detection system, which consists of 12 detectors on a single Si wafer, is used to increase the signal rate in RBS analyses. The increased rate is especially applicable to problems in which high statistical precision is required or when very low concentration levels have to be detected. In an effort to improve the limits of the depth resolution that can be obtained with classical RBS (proton and a beams), OConnor and Tan ( E a )have investigated the use of “heavy” ion beams (3 IZ1 I10) in RBS surface analysis. The use of heavy ions in surface analysis has principally received little attention because the poorer energy resolution of surface barrier detectors si nificantly reduces the depth resolution that can be achieve with these beams. Yet, by replacin the surface barrier detector with an electrostatic energy anafyzer (EEA), they demonstrate that exceptional improvements in depth resolution can be achieved and predict that, subject to the limitations of the theoretical models used in the computer simulation of heavy ion backscattering, depth resolutions as small as 0.5 nm may be achievable. Near the surface the improved depth resolution is chiefly a function of the improved energy resolution of the EEA. At greater depths in the sample, the enhanced resolution is due to the greater stopping powers of the heavy ion beams. Continuing with the subject of depth profiling, Ed e has developed an iterative technique by which exact dept profiling may be extended further (E%). High-resolution spectra are taken at two or more different angles and computer analysis is applied to obtain the distribution of the elements in the sample. For a target composed of two elements, the procedure can be performed by acquiring spectra at only two angles; more spectra are required when there is a larger number of target constituents. There are several computer codes available for RBS analysis work. The application of four of these modeling programs (PROFILE, SATT, RUMP, and CALC) to the analysis of oxidized surfaces is evaluated by Saulitis et al. (E36). Mclntyre et al. (E37) examined the standard fitting techniques used to resolve overlappin peaks in elastic scattering spectra and discuss the effects of t i e fitting routines on the accuracy of the final RBS results. Similarly, Niiler (E38) has discussed how the uncertainties in the stopping powers used in the simulation codes affect the uncertainties in the calculated elemental concentrations and coatin thicknesses. We also note in this section on modeling that Joergesen and Lilienfeld (E39)have measured the stopping cross sections for elemental yttrium, barium, and copper to facilitate the RBS analysis of high-T, superconductors. Elastic recoil detection (ERD) is complementary to RBS, and the two techniques are often used in combination. In ERD analysis the ion beam strikes the sample at grazing incidence angles and the recoiling ions that esca the surface of the sample are detected. The depth at whicRethe collision occurred and the concentration of the recoiling species can be deduced from the kinematics, stopping powers, and energy of the recoiling species. This technique is most frequently used to profile light elements in a heavy substrate. Reviews of ERD analysis can be found in refs E28, E40 and E41,and a systematic study of the use of 19F,W1, and %r as incident ion beams in ERD can be found in ref E42. 3. Other Nuclear Reaction Analysis (NRA) Techni ues. This review revealed that the two other ion-beamind9uced nuclear reactions that are commonly used for elemental analyses, excluding CPAA whichis discussed in section B of this review, are charged-particle emission reactions and resonant-charged-particle reactions. Like PIGE, other NRA techniques are most fre uently used in the analysis of light elements. More specficdy, these two techniques are generally chosen as the analysis method when one is interested in obtaining the depth profile distribution of light elements such as C, N, 0, or F. Reviews of these NRA techniques can be found in ref A71, E29, E30, and E84 while references to specific

d

g,

60R

ANALYTICAL CHEMISTRY, VOL. 62, NO. 12, JUNE 15. 1990

Table VI. Selected Applications of Other Nuclear Reaction Analysis Techniques reaction

T(d,a)H 12C(d,p)13C 14N(d,a)12C

ref

application

T-breeding blankets

TiC,Ny solid solutions TiC,Ny solid solutions

160(a,a)160

superconductors

180(p,a)15N

Ti metal surface Si semiconductor wafers

oxide films 19~(~,~)160

E85 E86 E86 E67 E88 E89 E90

Table VII. Selected Applications of Nuclear Microprobes E93,E94 A81 E97 E98 E99

archaeology biology and medicine F in enamel organ human and rabbit aorta mouse liver, muscle, and spleen material science Au implanted in Si C profiles in structural materials Mo layers on GaAs

E100,El01 A83 El01 E102,E103

semiconductors miscellaneous “water trees” in electrical cables

E104

applications are Fiven in Table VI. 4. Nuclear Microprobes. The combination of these IBA techniques with a nuclear microprobe is a owerful analytical tool that has now taken its place alon si& the electron and laser microprobes; application of nuc ear microprobes to a variety of research problems (see Table VII) has become routine. The majority of nuclear microprobe systems now provide researchers spatial resolution analysis on the order of 1-10 pm. Moreover, when the scanning microprobe is combined with a depth-sensitive NRA technique such as RBS or resonant nuclear reaction analysis, three-dimensional analyses can be performed. General reviews of nuclear microprobes have been published by Kiss (A79)and Bondarenko et al. (A82), while the use of microprobes for thrw-dmensional analysis is reviewed by Doyle (E91). Applications of nuclear microprobes to specific fields have been reviewed by Lindh in the area of medicine (A&), McMillan (A80) and Bakhru et al. (E921 in the area of material science, and Demortier (E93) and Brissaud (E94) in the area of archaeology. One major concern in the application of nuclear microprobea is the effects of the sam le surface topography on the analysis results. Hobbs et al. (E951 have investigated the influence of two geometric surface topographies on microprobe RBS analysis. The quantitative effects that a periodic triangular surface and a step surface have on the RBS spectra are discussed. As an example of the ower of nuclear microprobes, we of the corrosive behavior of mention Heck’s study lithium in stainless steel. The three-dimensional lithium distribution was determined in the micrometer range by combining a microprobe with the ‘Li( ,aI4He reaction. Moreover, the positional correlation of lit ium with oxygen and chromium was also determined by the simultaneous application of micro-RBS and micro-PIXE. Other s ecific applications of nuclear microprobes are given in $able VII.

K

(h6)

R

F. TRANSMISSION, ATTENUATION, AND SCATTERING METHODS Applications of the transmission, attenuation, or scattering of neutrons and y-rays have become common in many industrial quality control processes, and the simultaneous use of different measurement methods is routinely reported. Since the techniques involved are becoming rather routine, we give here some of the interesting uses of these analyses. Sowerby ( A 8 3 has described how coal and mineral processing operations can be controlled more efficiently using the information provided by nuclear techniques, and advances in bulk elemental analysis using neutron interactions have been reviewed by Gozani ( A m ) . Methods in the neutron-induced y-ray spectroscopy involved in well logging, the remote


analysis of boreholes, have been reviewed by Hertzog (A89). Schweitzer et al. (FI)have described a new technique for combining measurements using different types of nuclear reactions through a model based on both nuclear and geochemical considerationsto obtain routinely the concentrations of 10 formation elements in a single logging run. The use of Monte Carlo simulation to enerate the spectral response of well lo ing tools which are%ased on the (n,y) technique has been Rmonstrated (F2). The determination of soil moisture by fast neutron moderation (A86)has become a widely accepted practice. Holzhey (F3) and Sowerby et al. (F4) have combined the neutron method with y-ray backscattering and transmission to obtain very hi h precision moisture determinations. Leonfmdt (A84) and Baumbach ( A S )have discussed the uses of y-ray absorption and scattering and y-tomography as applied to construction engineerin and building materials problems. As a specific example o f t ese methods, it has been shown that it is possible to detect 5-mm-diameter reinforcing bars and 10-mm-thick air spaces in concrete blocks within 30 s (F5).The use of y-ray transmission or scattering for the continuous automatic monitoring of processes is well documented (F6-8). Pak and Vdovkin (F9,F10) have examined the effects of particle size on the results of y-ray backscattering analysis and find that the optimum energy of the primary radiatfon a t which the particle size effects are minimized increases with increasing absorbin properties of the sam les. Moreover, they have shown how t i e error of the methotcan be related to the differential size distribution of the particles. Singh (A46) has discussed the high sensitivity of positron annihilation s ectroscopy to the local atomic environment in materials, a n t in an a lication of this method, the effects of y-ray irradiation oFyow-density polyethylene has been determined ( F l l ) .

k

G. STANDARDS FOR ELEMENTAL ANALYSIS Many of the aforementioned analytical techniques use a comparative method for quantification in which the signal for one or more elements in an unknown sample is com ared to that from a standard. Because the use of standartfs is one of the most critical factors in these analyses, we devote a section of this article to a discussion of the standards that are used for nuclear and radiochemical elemental analysis. One publication in this area that will be of interest to many users is NBS Special Publication 260-111 by Gladney et al. ( A N ) . This most useful volume is a compilation of the elemental concentration data for the NBS (now NIST) Clinical, Biolo ical, Geological, and Environmental Standard Reference d t e r i a l s . Other general articles in this area include the review of geological and in0 anic standard reference materials by Jackson et al. (A42)an?the review by Hirai ( G I )on the preparation of standard samples for the NAA analysis of geochemical, industrial, environmental, and biological samples. Reference materials (RMs) provide laboratories with the means of evaluating existing analytical techniques, studying the effectivenessof new techniques or modificationsto existing techniques, and comparing results between different laboratories. Nuclear and radiochemical analyses continue to play a key role in the development and certification of such RMs. The ap lication of INAA and RNAA to the development, by the IAEA, of a new biological reference material which is representative of the diets consumed in Finland is described by Parr (B68). RNAA has also been used in the process of certifying a new NIST bovine serum SRM (G2) and INAA has been used in the certification of Japanese environmental reference materials (G3). For existing reference materials, INAA and PAA were used in an intercomparison project of Cd and other elements in IAEA H-8 horse kidney (G4) and the homo eneity of Chinese coal fly ash standards GBCW-F1 was testes by NAA (G5). A listing of other selected publications that are primarily concerned with reporting new analytical data in RMs is presented in Table VIII. The appropriate use of natural matrix standard reference materials is again reviewed by Becker (B44). The paper contends that, whenever possible, system calibration should be performed with primary standards (i.e,, pure or wellcharacterized elements or com unds) and that multielement matrix reference materials sRuld be used for quality assessment. The key reasons for this suggestion are the uncertainties associated with certified values and the limited

supply of these expensive reference materials. We would note that, although the paper specificallydeals with the calibration of INAA systems, the argument presented is valid and should be applied to many of the instrumental techniques described in this review. One major concern with the use of standard reference materials is the long-term stability of such materials. Zeisler et al. (G6) have investigated this problem for biological materials by examinin the elemental com osition of bovine liver SRM-1577 standarts over a time peridof 7 years. The initial evaluation of the concentrations of Zn, Se, and As which were determined by NAA at various times gives no indication of changes during the 7-year storage of fresh frozen tissues. Sill (C7)has addressed the question of long-term stability of 200-mesh solid standards that are used for radiochemical analysis. It was suggested that possible fractionation of the different sized particles may occur on standing over long time eriods. Small quantities of standards that were known to ave been undisturbed for 5-15 years were carefully removed from a thin layer at the top, middle, and bottom of the standards and analyzed for the radionuclide present. The results showed that little or no statistical differences among the three fractions from any of the samples were present at the 95% confidence level.

H. INSTRUMENTATION As we noted earlier in the section on books and reviews, two excellent books (A91,A92) on nuclear radiation detection and counting measurements are now available. The authors of these books should be raised for their efforts in making their works practical a n a informative. Since advances in nuclear analytical instrumentation typically follow developments in the basic nuclear sciences, these up-to-date monographs are a valuable resource for those planning on implementing state-of-the-art instrumentation and counting facilities. The review of modern liquid scintillation counting by Kobayashi and co-workers (A94) is also particularly noteworthy. Advances continue to occur in the area of laboratory instrumentation. Huddleston (A93) has discussed the advantages and constraints of robotic systems and their use for automation of analyses in radiochemistry laboratories, while Grundmann ( H I ) has evaluated the reliability, availability, and maintainability for a laboratory-automated storage and retrieval system for plutonium samples. The system studied includes a pneumatic tube transport system, bar-code readers, digital scales, storage carousels, and a control com uter. Bode and De Bruin (B24)have described an automate$ system for activation analysis with short-lived radionuclides. They have been able to reduce contamination of rabbits during transfer in this facility by constructing a system which utilizes plastic and carbon fiber rather than metal parts. Automated a-and y-ray spectrometry systems for the analysis of large numbers of nuclear waste samples have also been reported (H2). A particularly interesting example of y-ray spectrometry is presented by Nordemann (H3) who has considered the quantification of a sample of infinite extension with a 4.rr geometry around the y-ray spectrometer. I. DATA ANALYSIS AND COMPUTATIONAL METHODS Like the development of new instrumentation, the improvement of computational methods of anal sis serves to improve the lot of the nuclear analyst. Many of Kese advances have been presented in the previous sections when they related closely to a particular analytical method. Here we will attempt to describe some more generally applicable developments. In his review, Heydorn (A95)has presented possible pitfalls and sources of error that might be overlooked in contemporary nuclear analysis methods including calibration errors, identification errors, and photopeak evaluation errors. Braune (Zl) has examined the effect of stochastic perturbations on radiometric measurements and has emphasized that the Poisson distribution law must be replaced by a new distribution law to avoid errors. A method which consists of a comparison of the results obtained in both X-ray fluorescence and y-ray transmission measurements for the verification of matching of reference samples in uantitative X-ray fluorescence analysis has been describei (12). Korobochkin and Nikol'skii (13)have examined the detection limits involved ANALYTICAL CHEMISTRY, VOL. 62, NO. 12, JUNE 15, 1990

61 R


Table VIII. Selected Publications Relating to Elemental Reference Standards reference material Bowen’s kale IAEA A-11 milk powder IAEA H-4 animal muscle

IAEA H-5 animal bone IAEA H-8 horse kidney

IAEA H-9 mixed human diet

IAEA HH-1 hair IAEA MA-A-I copepod IAEA V-8 rye flour IAEA V-10 hay powder NBS SRM-1549 milk powder NBS SRM-1598 bovine serum NBS SRM-1566 oyster tissue NBS SRM-1567 wheat flour NBS SRM-1568 rice flour NBS SRM-1573 tomato leaves NBS SRM-1577 bovine liver

NBS SRM-2670 toxic metals NBS SRM-8431 mixed human diet NIES-5 human hair BCR-1 basalt Canadian SY-2,3 syenites CECA 679-1 iron ore Chinese GBCW-F1 coal fly ash GSJ JA-1 GSJ JB-1 basalt GSJ JG-1 granodiorite IAEA soil-5 IAEA soil-7 IAEA SL-1 lake sediment NBS SRM-77 burnt refractories NBS SRM-78 burnt refractories NBS SRM-123 B e C u alloy NBS SRM-1259 B e A 1 alloy NBS SRM-1648 urban particulate NBS 1632 coal USGS AGV-1 andesite

USGS BCR-1 basalt USGS DR-N diorite USGS FK-N potash feldspar USGS G-2 granite USGS GSP-1 granodiorite

62R

analysis method

elements determined

ref

RNAA RNAA RNAA PIGE RNAA INAA RNAA RNAA INAA, PAA RNAA PIGE RNAA RNAA RNAA. INAA RNAA RNAA RNAA RNAA RNAA RNAA RNAA NAA RNAA RNAA RNAA RNAA RNAA RNAA NAA RNAA RNAA PIGE RNAA RNAA RNAA RNAA RNAA RNAA INAA RNAA INAA CPAA INAA RNAA INAA RNAA RNAA INAA RNAA RNAA INAA RNAA RNAA RNAA NAA CPAA CPAA CPAA CPAA PIGE,PIXE INAA INAA INAA RNAA NAA INAA NAA NAA INAA RNAA NAA INAA INAA RNAA

cu Co, Ni Co, Ni C, N, 0 As, Cd, Cu, Hg, Zn many cu As, Cd, Cu, Hg, Zn many As, Cd, Cu, Hg, Zn C, N, 0 As, Cd, Cu, Hg, Zn Hg, Se many Co, Ni Hg, Se cu HE Ci, Ni As, Cd, Cu, Hg, Zn cu many Cr many Co, Ni Co, Ni Se As, Cd, Cu, Hg, Zn As, Se, Zn Cr Co. Ni C, N, 0 As, Cd, Cu, Hg, Zn Se Pt Co, Ni As, Cd, Cu, Hg, Zn As, Cd, Cu, Hg, Zn many REE many Be, Li, Mg many Sc, REE many REE Sc, REE many REE Sc, REE many cu cu cu many Be, Li, Mg Be, Li, Mg Be, Li, Mg Be, Li, Mg many As, Mn, Sb, V, Zn REE may REE REE many REE REE many REE REE REE manv REE

B226 B225 B225 Ell B234 B 106 B226 B234 G4 B235


Ell B234 B236 B68 B225 B236 B226 B233 B225 B234 B226 G8 B228 G2 B225 B225 B229 B235 G6 B228 B225 Ell B234 B229 B237 B225 B235 B234 G9 B215 g10

B182 G5 GI 1 g12

B215 g11 g12

B215 G11 G12 B226 B226 B226 G13 B182 B182 B182 B182 E4 B138 B90 B91 B214 g14

B91 G14 G14 B91 B214 g14

B90 B91 B214

NUCLEAR AND RADIoC%MICAL ANALYSIS

in determining soft @-particleactivity from surfactants on mineral surfaces. Numerous advances in activation analysis have been resented already, but many have direct applicability in ot&r areas. Antonov (14) has studied special cases of time interval optimization in activation measurements. Zagyvai and co-workers (15)have considered error estimation in y-ray spectrometry and have confirmed that their method ves accurate confidence limits combining both random and %?;as errors. A digital method of y-ray photopeak integration has also been evaluated and compared with other methods (16). The method of moments for multi let deconvolution in y-ray s ectrometry has been evaluatedty Atrashkevich et ! find the method for doublets and tri lets to be al. (17)ow fast and suitable for use on microcomputers. Al- ugrabi and Spyrou (18) have presented their methods for the off-line processing of cyclic activation data. We also note some reported software developments. The widely used SAMPO y-ray spectrum analysis program has been adapted to personal computers in a revised form called MicrosAMp0 and is reported to be suitable for both spectroscopic research and routine analysis (19). Similar1 ,the RAYGUN ray anal sis code (a descendant of CfAMANAL and 6RPANL) been converted for use to the PC environment (110). For INAA usin short-lived radionuclides, a computer ‘programfamil REV& has been developed for the interactive resolution andrresidualanalysis of decay curves with a known number of components of known half-lives (B36). Nelson (B37) has also reported the development of a computer program for complete instrumental neutron activation analysis with a personal computer. With the increasing importance of computerized literature searches, such as the ones used for this review, we are pleased to note a recent paper (111)that describes the International Nuclear Information System (INIS) database for literature retrieval on nuclear-related analytical techniques. An evaluation of the effectiveness of this database, whch is operated by the International Atomic Energy Agency and contains information on nuclear science and ita applications in various fields, is also provided.

hK

J. RADIOACTIVE TRACERS The use of radioactive tracers has found a place in so many different fields that even mentioning the many applications would be beyond the scope of this review. We are pleased to note that several new books and reviews (A97-103) on radiotracer methodology are available. While we did not have a copy of the book Radionuclide Tracers: Their Detection and Measurement by L’Annunziata (A97) for review, it appears to be a noteworthy addition to the literature. A particularly interesting radiotracer application illustrates the versatilit of this technique and the ingenuity of researchers in tiis area. Fu’ii and Takiue (JI)have described the radioassay of dual-labeled samples with a Cherenkov countin technique. The radioactivities, 32P-38cl and 8sRb3ec1 in d e i r studies, were determined simultaneously by taking advantage of a wavelength shifter in liquid scintillation counting. Other interestin applications we have noticed include the determination of surfactanta a t mineral surfaces (J2), the estimation of nuclear materials holdup in radiochemical processing (J3),and the monitoring of solvent extraction separations of tellurium (J4).

K. ISOTOPIC DATING METHODS We recommend the previous review (A104) and the review in this issue on “Atomic Mass S ctrometry” to those readers interested in accelerator-basegedatingmethods. While developments in accelerator mass spectrometry (AMS) are discussed there in some detail, we note a couple of radiohave chemical advances in this area. Vogt and Herpers (K1) discussed radiochemical separation methods for the determination of lon lived radionuclides by AMs, and Brendescribed the design and operation of an ninkmeijer (K2) automated cryogenic carbon dioxide collection system for AMs dating. Various aspects of conventional isotopic datin methods have been covered in recent reviews (A105-107). &he use of noble gas isotopes and other isotopic indicators in the dating of groundwater of various es has also been discussed by Lehmann and Loosli (K3),w%e the effect of isotope migration on groundwater dating has been explored by Luckner (K4).

!&I

For radiocarbon dating, the synthesis of ultrapure benzene from carbon dioxide is often an important step in the preparation of a suitable liquid for liquid scintillation counting. The simple preparation of a catalyst for the synthesis of benzene from ethyne has been reported (K5). The development of an aAr-39Ar laser-probe dating technique in which the pulsed laser beam was focused throu h a microscope lens onto a polished slab of rock has been fescribed (K6). By plotting the data in an isotope correlation diagram, the homogeneity or heterogeneit of the argon composition in each analyzed single grain coullrbe determined. Dalrymple and co-workers (K7)have examined two types of correlation diagrams used in the interpretation of aAr-39Ar incrementalheating data and have determined that they yield the same information,contrary to published assertions. They discuss the choice between graphical displays, neither of which was judged to be superior. Brown et al. (K8)have shown that the precision of Rb-Sr dating of micas can be improved by proper a plication of a leaching techniques, and Li (K9) has describeia new Rb-Sr isochron dating model of sedimentary rocks.

L. RELATED TOPICS While many developments occurred during the past 2 years, there can be no doubt that the biggest scientific news story was “cold fusion”. The excitement generated by the announcement by Fleischmann, Pons, and (belatedly) Hawkins ( L I ) that they had electrochemically induced the nuclear fusion of deuterium is unmatched in recent times. If cold fusion occurred as they suggested,a new, seemingly limitless source of energy could be just around the corner, and some revisions in our ideas about the laws of nuclear physics might be necessary. The observation of neutrons from electrochemical cells by Jones and co-workers (152) added to the fascination with this new phenomenon. Attempts to repeat these experiments began in laboratories around the world. Initial reports were encouraging, but soon the many roblems associated with the measurements of heat and nucEar radiations from the electrochemical cells were exposed. At the height of the cold fusion debate, 450 scientists gathered in Santa Fe a t the Workshop on Cold Fusion Phenomena. Despite the general conclusion that the expected levels of nuclear radiation (neutrons, photons, and charged particles) are not observed from these cells, several workers continue to observe the generation of heat and tritium. At this time, the final chapter on cold fusion remains without a definite conclusion, but it seems unlikely it will offer the energy source once anticipated. A development somewhat related to cold fusion is the observation of “cluster-impact fusion” (153). In this rocess, singly charged, heavy water cluster ions containing etween 25 and 1300 D20 molecules that are accelerated to modest energies (225-325 keV per molecule) have been observed to generate thermonuclear D-D fusion reactions on impact with titanium deuteride targets. The high fusion rates observed at these low kinetic energies suggest the possibility of a new path to fusion energy production. We also take this opportunity to update some subjects covered in our most recent review (AI) by noting that the masa of the neutrino now appears to be less than 13 eV, the half-life of the roton has not been measured, and neutrinoless double-P &cay has yet to be observed. The Chernobyl reactor accident has produced a number of scientifically interesting findings, and ita consequences, particularly in Europe, promise to be the subject of studies for decades. Bujdod (L4-6)has assembled an excellent bibliography of the accident.

f

M. SUMMARY At the end of this,our third review in this series,the “senior” authors would like to note the im ortant contributions of our new collea e. Not only has he Eelped li hten the load and contributegonsiderable expertise, but he %as permitted each of us to concentrate our efforts on a smaller set of subjects. Because of the breadth of this review, however, there are some covered topics that are still beyond our immediate research experience. Moreover, while we have been able to refine our computerized literature searching with each review, there may be some areas that are poorly covered in these searches. For these reasons, we again encourage our readers to contact us with suggestions. We benefit from both complaints and ANALYTICAL CHEMISTRY, VOL. 62, NO. 12, JUNE 15, 1990

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compliments. We are also pleased to receive reprints from authors who feel that their work should be included in the next review.

ACKNOWLEDGEMENT We thank Maggie Johnson for performing the computer literature searches and suggesting improvements in the search methods, June Smith for organizing and producing the bibliography, and Daniel Van Dalsem for assistance in roofing the manuscript. This task was greatly facilitated y their suggestions, coo eration, and patience. This work was supported in art gy the Department of Chemistry and the Graduate 8chool of the University of Kentucky and by the National Science Foundation (Grant RII-8110671) and the Commonwealth of Kentucky through the Kentucky EPSCoR Program.

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