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PRINCIPLES OF ENZYMATIC ANALYSIS H.U. Bergmeyer PARTIAL CONTENTS: Introduction. Theoretical Principles: Reaction Kinetics. Determinations of Michaelis Constants and Inhibitor Constants. Determination of the Substance Concentration of Metabolites (End-Point Methods). Other Measuring Techniques. Automation of Analysis. Enzymatic Analysis with Radiobiochemicals. Evaluations and Assessment of Experimental Results: Experimental Data. Experimental Results and Reference Units. Formulas. Index. 1978 268 pp. with 99 fig. and 30 tab. $23.80 paper U
CHROMAN AND RELATED COMPOUNDS S.E. Drewes Discusses the fragmentation behavior of six classes of compounds and reproduces spectra of characteristic types. Volume 2, Progress In Mass Spectrometry. 1974 138 pp. with 33 pictures and 102 schematic drawings $29.70 cloth t I POLYMER SPECTROSCOPY D.O. Hummel CONTENTS: The Subject of Polymer Spectroscopy. Vibrational Spectroscopy. High Resolution Nuclear Magnetic Resonance Spectroscopy. Electron Spin Resonance. Mass Spectrometry. Volume 6, Monographs in Modern Chemistry. 1974 401 pp. with 262 figs.. 76 tab. $55.55 cloth 11 CORRELATION TABLES FOR THE STRUCTURAL DETERMINATION OF ORGANIC COMPOUNDS M. Pestemer Provides a systematically arranged compilation of spectral data from the ultraviolet and visible absorption region of approximately 2300 organic compounds. 1975 157 pp. $50.00 cloth
produce very sharp lines and excellent fluorescence intensities (4). T h e rare earth ions are very favorably incorpo rated into the CaF·» precipitate and allow the precipitation to serve effec tively as a preconcentration and sepa ration step as well as a sample prepa ration step. Typical excitation spectra are shown in Figure 3 for Ho : l + and Rr : i + , two rare earth ions that have very similar electronic energy levels. Their lines are sharp and well resolved so that one ion can be easily excited without exciting the other. Since the lines in the fluorescence spectra are equally well resolved, the selectivity of the analysis for a particular rare earth ion is essentially complete. T h e line positions provide the information for a qualitative analysis of rare earths in a sample. Any of the rare earth ions that have optically accessible energy levels can be determined by this method with out the need to separate individual lanthanides. T h e lanthanides t h a t can be done include Pr, Nd, I'm, Sm, Eu, Gd, T b , Dy, Ho, Er, Tm, and Yb. We have recently found methods that can determine the remaining nonfluorescent lanthanides as well. Addition ally, it should be possible to perform analysis of actinides using the same ideas since the optical transitions of the actinides are very similar to the lanthanides. T h e detection limits in solution are generally a part per tril lion and correspond to ca. 4 X 1 0 - 9 mol % of rare earth in the CaF? pre cipitate. If the sample placed in the laser beam is 5 mg, there would be 0.4 pg of Er :!+ present. Smaller sample sizes, higher laser powers, and better detection electronics can all lower this value considerably. Linear calibration curves are maintained up to 1 ppm. Full details of the technique will be published shortly (5). Feasibility of Determining Other Ions T h e success of these experiments encouraged research on extending
these ideas to other analytes. If other analytes can be incorporated into the crystal lattice in association with a rare earth ion (the probe ion), the crystal field experienced by that rare earth ion will be different from the fields experienced by the other rare earth ions t h a t do not have the analyte nearby. Since the spectral transitions of rare earth ions are sharp, the differ ent crystal field levels can be resolved from each other and selectively excit ed with the same techniques discussed earlier. Since there is a 1:1 correspon dence between the analyte and a rare earth ion, the method should have comparable selectivity and sensitivity with the rare earth analysis studies. T h e feasibility of one method for achieving the required association be tween analyte and rare earth was shown for trace analysis of ΡΟί}~ by formation of a BaSO.i precipitate (6). In this work, new lines were produced in the Eu spectrum that were charac teristic of the presence of ΙΌ:ί~ and can be used for its quantitative analy sis. If BaCl 2 is added to a solution of Na-jSOi that also contains trace amounts of PO:,'- and a rare earth ion like Eu :1+ , a precipitate of BaSO., forms with PO,'~ and Eu :1+ impurities. Both of these ions require a charge compensation when they enter the BaSOi lattice. T h e charge compensa tion can be provided by defects in the lattice, or the two ions can compensate each other. The nature of the B a S 0 4 defects is unknown, but one might speculate the most favorable defects might be oxygep (Ov) and barium vacancies (Ba v ). Since the actual char acter of the defects is not important for this discussion, we will assume these are the defects for illustrative purposes. E u 3 + impurities could then be charge compensated by having one Ba v for every two Eu : ! + ions, and P0 4 ! ~ impurities could be compensated by having one 0 V for every two PO'i1- ions. T h e opposite charges on an ion (either Eu : , + or PO;,'-) and its compensating
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FUNDAMENTALS OF CHEMICAL RELAXATION H. Strehlow & W. Knoche Offers an introduction to chemical relaxation for easy comprehension of fast reaction techniques and their application to chemical problems. Monographs in Modern Chemistry, Volume 10. 1977 133 pp. with 41 fig. and 12 tab. $34.80 cloth Send to: Verlag Chemie International Inc. Dept. AC8 175 Fifth Avenue New York, New York 10010 Prices subject to change without notice CIRCLE 2 3 4
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Figure 3. Excitation spectrum of CaF 2 :Ho 3 H , E r 3 +
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1150 A · ANALYTICAL CHEMISTRY, VOL. 50, NO. 12, OCTOBER 1978
