环糊精超分子体系的手性识别研究──D,L-色氨酸对映体的手性识别荧光分析法

The paper reports the simultaneous fluorescence determination of D,L-tryptophanenantiomer by chiral recognition of β-cyclodextrin for the first time. Chiral discrimination isobserved for fluorescence emission of D- and L-tryptophan when complexed toβ-cyclodextrin, and is significantly related to reaction temperature, time and PH. The proposedenantiomeric resolution of D- and L-tryptophan is based on the non-fluorescellce emission ofLtryptophan in β-cyclodextrln solution at 35℃ and after 24 h standing by. The fluorescenceemission and absorbance of L-tryptophan disappear with the Increase of β-cyclodextrin at 35℃ and 24 h standing by, where as it is not observed for D-tryptophan. The detection limitsare 3.1×10-8 mol/L for D-tryptophan and 2.7 ×10-7 mol/L for L-tryptophan, respectively,with a RSD of 1. 0%-2. 6% (n=7). The method has been shown to be accurate with a ratioof 2%(molar ratio) of one enantiomer in the presence of the other. The observed pseudofirst-order rate constant is calculated. The reaction mechanism has been discussed usingpyrene as a fluorescence probe.