Mass transfer mechanism in chiral reversed phase liquid chromatography

•The five contributions to the mass transfer mechanism in chiral chromatography were measured.•These contributions include the short-range and the long-range eddy dispersion terms.•They also include the longitudinal diffusion and solid–liquid mass transfer resistance term.•A protocol permitting their accurate measurements was designed and followed.•The work was done with the stilbene enantiomers eluted on a Cellulose-1 column.

The mechanism of mass transfer in chiral chromatography was investigated using an experimental protocol already applied in RPLC and HILIC chromatography. The different contributions to the reduced height equivalent to a theoretical plate (HETP) include the longitudinal diffusion HETP term, the solid–liquid mass transfer resistance HETP term, the short-range eddy dispersion HETP term, and the long-range eddy dispersion HETP term. Their accurate measurement permits the determination of the adsorption rate constant kads of trans-stilbene enantiomers on a column packed with Lux 5 μm Cellulose-1 particles. The experimental results demonstrate that the number of adsorption–desorption steps per unit time of chiral compounds on polysaccharide-based chiral stationary phases is four orders of magnitude smaller than that of achiral compounds.