INVESTIGATION OF A CIRCULAR-DICHROISM SPECTROPHOTOMETER AS A LIQUID-CHROMATOGRAPHY DETECTOR FOR ENANTIOMERS - SENSITIVITY, ADVANTAGES AND LIMITATIONS

The advent of effective, enantioselective stationary phases in liquid chromatography (LC) has spurred interest in chiroptical detection techniques for method validation and for divining other stereochemical information. Chiral molecules bearing a chromophore have the ability to absorb differently right and left circularly polarized light. This is known as circular dichroism (CD). The use of a commercial CD spectrophotometer as a LC detector is discussed. Various instrumental parameters have a significant influence on the detection sensitivity of chiral compounds and are evaluated. The ability to choose the optimum UV wavelength was particularly advantageous. The usefulness and limitations of the two-detector approach (UV and CD detectors in series) for enantiomeric ratio determination without chiral resolution is discussed. Finally, the limitations of chiroptic devices as stand-alone detectors are considered.