CROSS-LINKED POLYMER-COATINGS FOR CAPILLARY ELECTROPHORESIS AND APPLICATION TO ANALYSIS OF BASIC-PROTEINS, ACIDIC PROTEINS, AND INORGANIC-IONS

A coating process for covalent coupling of fully formed polymers to si lane-treated capillaries is described. The coupling process occurs thr ough free-radical sites created on both the silane and polymer during the polymer cross-linking process. Coupling and cross-linking take pla ce simultaneously, resulting in a densely cross-linked layer on the ca pillary surface. By using this coating procedure, several polymers, su ch as polyacrylamide (PA), poly(vinylpyrrolidone) (PVP), and poly(ethy lene oxide), were successfully anchored on capillaries treated with si lanes such as (methacryloxypropyl)trimethoxysilane. (MET), chlorodimet hyloctylsilane (OCT), and trimethyoxyallylsilane. High-resolution sepa rations of basic proteins with achieved using efficiencies of 500 000 plates/50 cm were achieved using polymer-coated capillaries such as ME T-PVP, MET-PA, and OCT-PCP. Similarly, high-resolution separations of milk proteins and hemoglobin variants were achieved by a MET-PVP-coate d capillary. In addition to neutral polymers, the above coupling proce ss was also suitable for attaching cationic polymers, Fast and efficie nt separations of acidic proteins and small inorganic anions were achi eved using an acrylamide-based cationic polymer-coated capillary. The coating process described here is easy to implement and results in rep roducible, stable capillary coatings for capillary electrophoresis.