LIQUID-CHROMATOGRAPHIC STUDIES OF THE EFFECT OF TEMPERATURE ON THE CHIRAL RECOGNITION OF TRYPTOPHAN BY SILICA-IMMOBILIZED BOVINE ALBUMIN

The practical application of immobilized bovine serum albumin (BSA) as a chromatographic packing for the resolution of enantiomers has been demonstrated by a number of investigators. In most cases minor changes in eluent conditions lead to very large variations in chromatographic resolution. Because of this, a better understanding of basic separation mechanisms and the influence of solution equilibria and other pertubating conditions such as temperature are necessary in order to assure chromatographic reproducibility as well as to design novel applications. The current work examines the effect of temperature and eluent pH on the chromatographic performance and binding characteristics of silica-immobilized BSA. Measurements of both the background and the site-specific binding are made using D- and L-tryptophan. In the case of the latter isomer, maxima in plots of the natural logarithm of the capacity factor vs reciprocal temperature are observed and may be due to a phenomenological change in the bound protein.