High performance liquid chromatography as a molecular probe in quantitative structure-retention relationships studies of selected lipid classes on polar-embedded stationary phases

Abstract

Studies on the retention mechanism of lipid classes (phospholipids, sphingomyelin) were performed using three polar-embedded stationary phases for which diol, phosphate, amino, and amide moieties were incorporated into the alkyl chains of the stationary phases. Their structural descriptors were determined using the quantum-mechanical method. The retention behavior of the analytes was investigated as a function of different binary hydro-organic mobile phases containing (90%/10% acetonitrile (or methanol)/0.1% formic acid). It was found that the elution order on the tested stationary phases was governed chiefly by the hydrophilicity of the analyte and indicated the existence of a hydrophilic interaction liquid chromatography retention mechanism. Quantitative structure-retention relationships studies were performed to further elucidate the retention mechanism. These studies showed that the dominant analyte descriptor influencing retention on the alkyl-amine stationary phase was the logarithm of the octanol-water partition coefficient. For the phospho-diol and alkyl-amide stationary phases, the dominant analyte descriptor influencing retention was the molar volume and solvent accessible area of the analyte, respectively.