Books: Complete Coverage of Chemometrics - Analytical Chemistry

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Books

IR for Newcomers

Modern Techniques in Applied Molecular Spectroscopy Francis M. Mirabella. Ed. John Wiley & Sons 605 Third Ave. New York, NY 10158 1998, 403 pp., $59.95

In this book, the editor has assembled nine chapters written by various experts, covering a largefractionof the methodologies used for analytical applications of vibrational spectroscopy. Though there is some mention of measurements outside of the IR and near-IR regions, the book is really about applications and sampling approaches in IR and Raman spectroscopies. The various authors have done a good job at providing up-to-date references and practical applications. In general, the chapters are well written and quite useful as general references. They are most valuable as an introduction to the field. The first chapter lays the theoretical groundwork for vibrational spectroscopy. As such, the information is readily available in other texts. I found some of the descriptions about instrumentation historically interesting but,fromthe point of the remaining chapters, somewhat irrelevant. From my reading there is no IR data presented in the bookfromanything other than interferometers. The descriptions of dispersive instrumentation, although interesting, really do not lead into the other chapters. The sections on proper operation 812 A

of FT instruments are, however, quite good and deserve close reading by anyone practicing in this area. The chapter is extremely well referenced, and interested readers are pointed in the correct direction for further study. Specular and attenuated total-reflection (ATR) measurements are reviewed in the next two chapters, which are very well done. Significant applications are discussed, which bring the theoretical basis for the measurements into clear focus. In the chapter on ATR, much of the background material is easily obtained in traditional texts on reflection spectroscopy, but the applications are well explained. The chapter on photoacoustic measurements is well done and is even better than the previous chapters' examples. Rapidscan and step-scan instrumentation are covered. IR and Raman microspectroscopy are covered in the next two chapters. The particular strength of these chapters lies in the discussions of appropriate microscopic techniques, and choices for objectives and magnifications. Again, both chapters include nice examples and adequate references for the interested reader. The book concludes with chapters on IR emission andfiberoptics. Both chapters have strong background discussions, illustrations of the techniques, and numerous example applications. This book will be most valuable to newcomers to the field of analytical vibrational spectroscopy, especially those in general analytical labs. If one is faced with a characterization problem and is unsure of which are the appropriate sampling methods to use, the information assembled here will be very valuable. For those who have been active in one or more of the areas covered, the book will probably be of less value. Reviewed by Bruce Chase, DuPont Experimental Station

Analytical Chemistry News & Features, December 1, 1998

Complete Coverage of Chemometrics

Handbook of Chemometrics and Qualimetrics: Part A D. L. Massart, B.G.M. Vandeginste, L.M.C. Buydens, S. DeJong, P. J. Lewi and J. Smeyers-Verbeke. Elsevier Science B. V. Sara Burgerhartstraat 25 P.O. Box 211, 1000 AE Amsterdam 1997, 867 pp., Part A: $273

Changes in the field of chemometrics have come at a rapid pace over the past decade, and this new handbook is a direct reflection of the evolution of the field. Some 11 years ago, a version of this book was published as a textbook for chemists entering thefield.That version focused on the basics of the main chemometrics methods as practiced then, but with an emphasis on applications of classical statistics. As thefieldhas grown, so has the book's scope size, and, unfortunately, price. The textbook has become a twovolume handbook covering the theory and practice of chemometrics aimed now at a slightly more sophisticated reader. One aspect that has remained constant is that this set offers the most complete erage available of thefieldof chemometrics in a single text Part A of the handbook focuses on the more statistically oriented aspects of che-

mometrics. This book covers a wide range of fairly routine statistical matters, including distributions, hypothesis testing, ANOVA, simple and multiple linear regression, and experimental design. Five chapters are devoted to aspects of experimental design, a clear indication of the importance of this topic to modern chemometric methods. Some less common statistical methods also receive treatment, including nonlinear regression, control charts, and robust statistical methods. Also brief chapters are devoted to information theory fuzzy regression, and pattern matching. The book is distinguished from the many, more traditional statistical treatments of these subjects by the nature of its coverage. For example, the chapter on time series analysis approaches that subject from the view of process modeling. A discussion of process sampling fits quite naturally into this view. In a more traditional statistics-oriented text, the two would be separated, and it would be left to the reader to find the connections. A chapter on basic descriptive statistics is grounded in the use of these statistics for the representation of quality. Several chapters covering other basic statistical material are tied together in two chapters on validation. The first chapter devoted to this topic focuses on internal method validation and covers the usual analytical figures of merit. The second chapter focuses on interlaboratory studies. The coverage here makes use of the familiar box and Youden plots and introduces some of the less-known methods to chemists. Much of the material distinguishing chemometrics from classical statistics concerns soft modeling of multivariate data. Although these methods are covered in the two-volume set, Part A offers only an introductory chapter on principal components analysis. This chapter is an

introduction to principal component analysis and its use for method validation. Brief coverage includes evolving principal component analysis, principal components regression, and partial least squares regression. Classification is provided here as well. The substance of more recent research on multivariate data analysis is reserved for Part B, a separate book not reviewed here. A few of the more recent discoveries do appear in Part A, though. ACE and MARS, two recent advances in nonlinear regression, are discussed in that chapter, and the two final chapters cover recent advances in optimization theory and practice. One focuses on optimization in a rather broad perspective, covering material from the simplex method, the simplex optimization scheme, multicriteria optimization, and Taguchi experimental designs. The second focuses on the use of genetic algorithms, simulated annealing, and Tabu searches for exploration of response surfaces. The text is well laid out, with a format much like that used in the earlier text. References to literature through 1996 appear in many of the chapters. A thorough subject index makesfindingmaterial easy, but there is no author index. Many examples help to clarify the workings of the numerical methods discussed in the text, which are supplemented with many black and white figures. The quality of these figures varies from publication-quality hand drawings to computer-generated two- and threedimensional displays. With any multiauthor text, the challenge is to integrate the material and the differing treatments, and then to set a consistent tone and outlook throughout the volume. This task is especially difficult in chemometrics because of the multitude of mathematical formula. The authors clearly have made internal consistency a priority in revising and updating

the book, but, in my opinion, they come close, but do not quite accomplish this goal because the transition from text to handbook is incomplete. Some chapters have a fairly extensive list of references, as one would expect from a handbook, while others have but a few research papers, mainly from a narrow set of research groups. The material is of far more use to the expert, and especially to the student, when references to key books and reviews are provided along with references to selected research papers. Also, the level of the 27 chapters in Part A varies a good deal; some seem expository, with detailed examples, and are probably better suited to an introductory text, while others are distillations of literature more appropriate to a handbook. Despite this flaw, the book has a good deal to offer. The division of material between Parts A and B is such that anyone seeking exposure to the more recent developments in chemometrics will want Part B, but will benefit from Part A for exposition of background material. The book's breadth will make it an attractive reference book for chemists with an interest in getting into the basic chemometrics literature. In addition, the integration of a lot of classical statistics with analytical chemistry provides an accessible entrance to classical statistics for many chemists. The book also provides necessary exposure to a wide range of basic skills associated with data analysis—skills often lacking in those who move directly from a background in measurement chemistry to using multivariate, computer-based methods like partial least squares regression. The book's cost and breadth make it impractical to use as a text in a class, but it will undoubtedly serve well as a useful reference for chemists. Reviewed byStevenD. Brown, University of Delaware

Analytical Chemistry News & Features, December 1, 1998 8 1 3 A