New Trends in Chiral High-Performance Liquid Chromatography-Tandem Mass Spectrometry

This chapter deals with the most relevant advances in chiral analysis and focuses on highly efficient enantioseparations by liquid chromatography and its hyphenation with mass spectrometry (MS). The use of MS for chiral discrimination has been successfully done by enantiomer interaction with chiral reference reagents or environment. This has been achieved by host–guest association, ion–molecule reactions in gas phase or complex dissociation. All modes can provide different mass spectrometric signals for the two enantiomers and relative intensities depending on the enantiomeric ratio that can be experimentally estimated. A more interesting type of analysis in terms of performance and sensitivity is enantio-high-performance liquid chromatography (HPLC)-MS. This chapter examines the recent trends and advances in chiral HPLC columns, highlighting the types of chiral selector, mobile-phase compatibility with MS detection, as well as efficient and innovative column packing particles. Future directions for enantioseparations are development of very efficient chiral columns and ultrafast HPLC runs. The latter topic is indeed a consequence of the former, due to the high working pressure arising from new-generation chiral stationary phases. The two routes concern, on the one hand, the use of very small fully porous particles (<2 μm) and, on the other hand, chiral selectors bonded to superficially porous particles (core-shell technology). Some fundamental studies have already been conducted by these authors, particularly to understand deeply the mass transfer kinetics and its influence on band broadening effects in chiral separations. Further studies need to be done on chiral stationary phases obtained with superficially porous particles since some critical aspects are not obvious and could remarkably affect their development.