Preparation and characterization of silica monolith modified with bovine serum albumin-gold nanoparticles conjugates and its use as chiral stationary phases for capillary electrochromatography

This paper describes the development of silica monolith modified with bovine serum albumin-gold nanoparticles (BSA-GNPs) conjugates as chiral stationary phases for capillary electrochromatography (CEC). The bare monolithic silica column was prepared by a sol-gel process and has been modified chemically with 3-mercaptopropyltrimethoxysilane to provide thiol groups, followed by immobilization of gold nanoparticles via the formation of an Au-S bond and modification with BSA as the chiral selector via the nitrogen lone pair of electrons. It has been demonstrated that the monolithic chiral stationary phases can be used for the enantioseparation of a number of phenylthiocarbamyl amino acids (PTC-(D/L)-AAs) by CEC. Ten pairs of tested amino acids enantiomers were successfully resolved within 18 min under optimized conditions, and the resolution values were in the range of 1.486-2.083. With PTC-(D/L)-tryptophan used as the probe solute, the influences of applied voltage, organic modifier and buffer pH in mobile phase on apparent retention factor, enantioselectivity and resolution factor were also investigated.