Chiral stationary phase selectivity, coupled columns and hyphenated systems in bioanalytical applications

Selectivity is key to achieve assay specificity and accuracy in bioanalytical applications. It can be introduced on various levels of an analytical process, in the course of sampele preparation, by derivatization, chromatographic separation, two-dimensional separations, ion-mobility spectromety and mass spectrometry. Chiral stationary phases (CSPs) enrich the column toolbox. They are established tools for enantiomer separations of chiral drugs, but have also other applicabilities beyond the field of enantiomer separations. In this presentation, the potential of chiral stationary phases in metabolomics and lipidomics, for therapeutic peptide analysis, and nucleic acid pharmaceuticals will be discussed. When it comes to real bioanalytical applications, chromatographic selectivity is usually combined with mass spectrometry (MS) to cope with assay specificity limitations in presence of real matrix and insufficient chemoselectivity. Smart MS designs can work in concert with CSPs for challenging separations such as in the analysis of phosphatidylinositolphosphate constitutional isomers which are regulators of cell membrane dynamics. Multidimensional LC combining achiral chemoselectivity with steroselectivity of CSPs is another option to deal with complex sample mixtures. Ist potential will be illustrated for absolute configuration determination of a natural product with tetrapeptide structure. Chiral columns have some limitations regarding their chemoselectivity. It often happens that enantiomers are well resolved but structural analogs or constitutional isomers overlap. It will be discussed how ion mobility mass spectrometry (IM-MS) coupling can combine enantioselectivity of CSPs with diastereomer/constitutional isomer selectivity of IMS for establishing enantioselective amino acid profiles in about 1 min.