Hyphenated affinity capillary electrophoresis with a high-sensitivity cell for the simultaneous binding study of retinol and retinoic acid in nanomolars with serum albumins

► Using of a high-sensitivity cell/ACE for the estimation of precise high binding constants. ► Investigating simultaneously of retinol and retinoic acid in nanomolars with HSA and BSA. ► Decreasing the adsorption of protein by reducing the required additives concentrations. ► Using of mobility ratio based on nonlinear regression to deduce high binding constants. ► Studying the competitive binding between retinol and retinoic acid on HSA and BSA.