The initial chapter on mobile and stationary phases for supercritical fluid chromatography (SFC) covers the topic well, although those familiar with SFC will find that much of the first quarter of the chapter rehashes the basics. The rest of the chapter deals with the use of mobile phases other than CO2, the advantages and disadvantages of the various ways of adding modifiers to the fluid, and secondary effects attributable to swelling of the stationary phase. These and the other specific topics contain many recent references that allow the reader to delve deeper if desired. The chapter on properties and uses of polymer-based packings for reversed-phase liquid chromatography (RPLC) covers a relatively new topic with which few chromatographers are familiar. This separation approach has great potential application because of its compatibility with mobile phases that silica-based packings cannot tolerate. The discussion of the problems inherent in polymer-based packings, such as less resolution because of the wider distribution of particle properties and less selectivity because of the fewer types of derivatization, are thor-
oughly discussed. The small number of examples of actual separations seems to reflect the newness of this type of separation, and not a lack of potential applications. Anyone doing extensive development of aqueous RPLC will find that this chapter opens up some totally different approaches. Although one chapter on separation of large polycyclic aromatic hydrocar-
êé...
deals with factors affecting selectivity and retention in separations...
bons deals with a topic of limited interest, the use of these molecules as probes to determine the mechanisms in RPLC gives insights useful in developing separations for other highly structured molecules such as polypeptides or chiral molecules. Topological factors, such as length and planarity, are discussed, as is a computer-based retention prediction approach. Several advantages made possible by
miniaturization in HPLC are discussed in one chapter. This chapter specifically describes preconcentration of analytes using column switching to improve sensitivity, using an electrochemical cell, and fast atom bombardment mass spectrometry for detection in micro LC. These techniques are quite sophisticated, so the average reader will gain general knowledge only. The two final chapters deal with the use of densitometers in TLC. The first discusses the nonlinear response of densitometers and associated problems in quantitation. The second discusses the instrumental hardware and how it affects results. Both are very thorough, allowing the novice to appreciate the various choices in instrumentation and the complexity of quantitative analysis by TLC. As with the previous volumes of this series, the editors have chosen contributors who are experts in areas of current interest. The topics are varied enough that most readers will find at least a chapter or two useful, and the coverage in each is thorough enough that even an expert can pick up some new information.
For Those Involved in t h e V i t a l Field of Surface a n d Colloid Chemistry
Langmuir
CSZCCCSCSCS
The ACS Journal of
Surfaces and Colloids
Langmuir is a monthly journal of broad coverage that brings together research from all aspects of the field: ultra-high vacuum surface chemistry and spectroscopy, heterogeneous catalysis, all aspects of interface chemistry involving fluids, and disperse systems. Langmuir publishes peer-reviewed research in: * "Wet" Surface Chemistry * "UHV" Surface Chemistry * Disperse Systems * Electrochemistry * Surface Structure; tunneling electron microscopy EDITOR William A. Steele, Pennsylvania State University ASSOCIATE EDITORS
A.T. Hubbard, University of Cincinnati R.L. Rowell, University of Massachusetts
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ANALYTICAL CHEMISTRY, VOL. 62, NO. 22, NOVEMBER 15, 1990 · 1175 A
