Automated sample preparation techniques for the determination of drug enantiomers in biological fluids using liquid chromatography with chiral stationary phases

The determination of drug enantiomers has become of prime importance in the field of pharmaceutical and biomedical analysis. Liquid chromatography (LC ) is one of the most frequently used techniques for achieving: the separati on and quantitation of the enantiomers of drug compounds. In the bioanalyti cal field, the integrated systems present an interesting alternative to tim e-consuming sample preparation techniques such as liquid-liquid extraction. Solid phase extraction (SPE) on disposable cartridges, dialysis or column switching are sample preparation techniques that can be fully automated and applied to enantioselective analysis in biological fluids. The selection o f the most appropriate LC mode and chiral stationary phase for enantiosepar ations in bioanalysis is discussed and some aspects of these automated samp le preparation procedures are compared, such as selectivity, detectability, elution of the analytes from the extraction sorbent, sample volume and ana lyte stability.