NEW BOOKS
Now from Regis . . . TABs* for rapid Quantitative & Qualitative GLC analysis of all 20 Natural protein amino acids *Regis name for N-trifluoroacetyl n-butyl ester A new, rapid quantitative GLC method for the analysis of the 20 natural protein amino acids has been developed by C. W. Gehrke and D. C. Stalling.1 The new method consists of a sim ple procedure for the rapid quan titative conversion of amino acid mixtures to N-trifluoroacetyl ra-butyl esters which can be reproducibly separated and assayed by a single GLC system. The new method is rapid . . . all 20 derivatives can be eluted within 1 hour. It is accurate . . , its results are in excellent agreement with ion-exchange chromatographic analysis. It is economical... it can be carried out on a relatively inexpensive GLC unit of multi purpose application. Complementing this new GLC approach, Regis now offers for the first time, all 20 TABed* natural protein amino acids in standard ized solution form for use as com parative references. Regis TABed* amino acids are supplied in handy kits which in clude a condensed description of the derivatization and analytical method as detailed by Gehrke and Stalling.1 (1) Separation Science, II (1), p. 101-138 {1967) Further details on Regis TABs are available upon request.
Regis Chemical Co. 1101 N. Franklin St. Chicago 60610 A/C 312 Whitehall 3-1622 Circle No. 10 on Readers' Service Card 76 A
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ANALYTICAL CHEMISTRY
Long Island City, Ν. Υ. 11101. The discussions of electrochemical and spectrochemical methods for determination should prove useful to the analyst, and a number of biological analyses are cited. The last chapter "The Analytical Chemistry of Polonium" by Robert C. Langc adds relatively little to what has already been published in a. relatively large number of reviews of polonium chemistry. The text of this chapter consists of only 20 pages and of the 133 references cited, too many have pre viously been reviewed. The chapter is probably of most interest as an intro duction to polonium chemistry.
Interactions in Electrolyte Solutions.
G. H. Nancollas. χ + 214 pages. Elsevier Publishing, 52 Vanderbilt Ave., New York, N. Y. 10017. I960. $14.30. Reviewed by George Scatchard, Massachusetts Institute of Technology, Cambridge, Massachusetts. 02139. The subject of this book is the deter mination and interpretation of equilib rium constants of reactions involving at least one ion. Apparently the more precisely descriptive titles have been preempted. It is limited to aqueous so lutions and, except for the ionization of weak acids, to mononuclear complexes of metal ions. The book docs not profess to be com prehensive but is planned as a survey which will enable the interested reader to go to the proper literature. There are 477 literature references, 58 to Nan collas' own papers. Since they are given at the ends of the six chapters and of the seven tables in the appendix there is much duplication, particularly in the latter. There is obviously a slant toward Nancollas' own interests, the determination of the enthalpy and en tropy, as well as the free energy, by combining calorimetric measurements with the equilibrium studies. My ac quaintance with the field is not suffi cient to be sure that no other field is neglected, but the newer tools are cer tainly sufficiently introduced. My chief criticism of this book applies also to most, if not all, dis cussions of equilibrium constants for re,i étions involving ions. They ignore the facts that there are no truly free ions in an electrolyte solution and that therefore any calculation of an equilibrium constant depends upon an arbitrary definition of "free ions." If all workers could agree on a definition, this would make no difference. However, there is the related difficulty, recognized by Nancollas, that different
methods of measurement may determine different equilibria. This can affect the determination of entropy from free energy and enthalpy if the equilibrium and heat measurements are for different reactions. A related criticism is that the association constant for an ion pair of Bjerrum should not be compared with other association constants or criticized for the arbitrary dividing line. Bjerrum himself said [Trans. Faraday Soc, 23, 433 (1927)], "The distinction between free and associated ions was not a chemical one, but only a mathematical device making possible an approximate calculation of the effect of interionic forces under conditions where the approximation of Dcbye and Hiickel could not be used." Another criticism is of the perpetuation of the myth that disturbing effects can be swamped out by working at high ionic strength, which is based on a few experiments of Br0nsted before 1920 at constant equivalent concentration. A much better measure is av> of Harned. It does often decrease with increasing ionic strength, but not very much. I found very few typographical errors, and I was pleased with the phrase "References p. . . ." at the bottom of each right hand page. More important, if I were to return to the study of complexes I would keep Nancollas' book very handy, at least until I was well started.
Quantitative
Freshman
Chemistry.
J. B. Nordmann, E. S. Kuljian. vi + 132 pages. Burgess Publishing Co., 426 South Sixth St., Minneapolis, Minn. 55415. 1966. 83.25. Paperbound. Reviewed by Gilbert H. Ayres, Department of Chemistry, The University of Texas, Austin, Texas 78712. This manual is designed to combine illustration of principles and applied quantitative analysis into a one-semester or two-quarter course for science and engineering majors who have passed high school chemistry. Much of the work consists of measurements (hence, "quant") made to obtain data for illustration of principles. The authors have done a satisfactory job in selection of work illustrative of the book's title. Although a few of the experiments overlap work traditionally done in quantitative analytical chemistry, there is no implication that the work of this course is a substitute for classical quantitative analysis. Although the authors state that they have de-emphasized descriptive chemistry, this reviewer is glad to note the in-
