Surface Initiated Polymerisation of a Cationic Monomer on Inner Surfaces of SiO2-capillaries and Electrophoretic Separation of Cationic Analytes.

JOANNA WITOS; M. KARESOJA; PATRICIA W. STEGE; E. KARJALAINEN; H. TENHU; MARJA L. RIEKKOLA

Copenhagen

Workshop; 49th Nordic Polymer Days; 2012

[2-(methacryloyl)oxyethyl]trimethylammonium chloride (MOTAC) was successfully polymerized by surface initiated atom transfer polymerization method (SI-ATRP) on the inner surface of fused-silica capillaries resulting in a covalently bound poly([2-(methacryloyl)oxyethyl]trimethylammonium chloride) (PMOTAC) coating. PMOTAC-coated capillaries provided in capillary electrophoresis an excellent run-to-run repeatability, capillary-to-capillary and day-to-day reproducibility. The capillaries worked reliably over one month. The positively charged PMOTAC-coated capillaries were applied to successful capillary electrophoretic separation of three standard proteins and five β-blockers. In addition, challenging high- and low-density lipoprotein particles (HDL and LDL) could be separated. Covalent grafting of polyelectrolytes to the silica surfaces is a method of choice to prepare stable capillaries for electrophoretic studies. The covalently bound stable PMOTAC coating effectively shields the silanol groups on capillary surfaces and reduces the adsorption of cationic analytes.