Bioinert chiral columns with Dursan-coated stainless-steel hardware for enantioselective liquid chromatography of polar analytes

Abstract

Analyte interactions with metal surfaces of column hardware are a well-known source of peak tailing, carry-over and poor recovery, particularly for polar compounds with chelating properties that have a high metal affinity and surface adsorption potential like phosphonic acids, amino acids and hydroxy carboxylic acids. While biocompatible and bioinert column hardware has emerged as a promising solution for non-chiral liquid chromatography, its impact on enantioselective chromatography remains underexplored. In this study, two quinine carbamate based chiral stationary phases, CHIRALPAK QN-AX and ZWIX(+), were evaluated in both Dursan-coated and conventional uncoated stainless steel column hardware. Dursan is a functionalized amorphous silicon oxide coating leading to chemical inertness and was tested herein for its ability to improve the enantioseparation performance of amino acids, amino phosphonic and phosphinic acids and hydroxy carboxylic acids. For the majority of amino acid enantioseparations reduced peak width, improved resolution and less tailing could be realized on ZWIX(+). The most pronounced benefits were observed for an aminophosphonic acid while the positive effect was moderate for a corresponding aminophosphinic acid. An improvement in chromatographic performance with Dursan-coated hardware was also found for the more hydrophilic hydroxy carboxylic acid enantiomer separations (2-hydroxyglutarate, lactate) on QN-AX while the effect was negligible for less hydrophilic congeners. These findings highlight the compound-specific nature of surface interactions and underscore the value of chemically inert column hardware in enantioselective LC. Overall, the study supports the use of Dursan-coated columns as a viable strategy for advancing bioinert chiral separations in pharmaceutical, bioanalytical and metabolomics applications.