Complexation with Cu(II) ion in strong aqueous base, combined with visible range circular dichroism detection, were used to quantitatively differentiate among the L-enantiomers of the GG, GA, GY, AG, AA, AY, YG, YA, and YY dipeptides and the D-enantiomer of GA. Using ellipticity data at all (n = 1500) wavelengths in the measured spectra, and two novel data reduction procedures, quantitative determinations were made of the compositions of binary mixtures. For mixtures made with the L-GA and D-GA enantiomers, the accuracy of the measured enantiomeric purities was better than 0.17 % over the 1-48 % range for the minor component. The method has considerable potential for use in quality control of peptide and protein biotechnological drug forms.Copyright 1999 Wiley-Liss, Inc.
