Polymerized phospholipid bilayers as permanent coatings for small amine separations using mixed aqueous/organic capillary zone electrophoresis

Phospholipid bilayer (SPB) coatings have been used in capillary electrophoresis to reduce the nonspecific adsorption between the capillary wall and cationic analytes. This paper describes the use of the polymerizable lipid 1,2-bis(10,12-tricosadiynoyl)-sn-glycero-3-phosphocholine (Diyne PC) as a permanent capillary coating. A supported phospholipid bilayer was formed on the capillary walls and polymerization was performed in situ using ultraviolet irradiation. The polymerization reaction was monitored by UV–visible absorbance spectroscopy and atomic force microscopy. The EOF of the polymerized Diyne PC coating was moderately suppressed (2.0 × 10−4 cm2/V s) compared to a non-polymerized Diyne PC bilayer (0.3 × 10−4 cm2/V s), but the stability was improved significantly. Separations of benzylamine, veratrylamine, phenylethylamine and tolyethylamine using a poly Diyne PC coated capillary yielded efficiency of 220,000–370,000 plates/m and peak asymmetry factor 0.48–1.18. Specifically, the poly(Diyne PC) coating provided improved separation resolution in NACE due to the reduced surface adsorption.