CELLULOSE ACETATE-COATED FUSED-SILICA CAPILLARIES FOR THE SEPARATION OF PROTEINS BY CAPILLARY ZONE ELECTROPHORESIS

Thin-film coatings of cellulose acetate on the surface of fused-silica capillaries were tested for the separation of proteins by capillary z one electrophoresis. The coating procedure is very simple and only inv olves the filling of the capillary with cellulose acetate solution, fo llowed by flushing the capillary with helium. The coating appears to m ask the underlying silanol groups towards basic proteins effectively; column efficiencies up to 10(6) plates per metre were achieved for rib onuclease A. The high efficiency, the batch-to-batch and the run-to-ru n reproducibility and the long-term stability of the coating are advan tageous features of the method. The coating procedure provides a simpl e, stable and easy to reproduce method of surface deactivation and can be applied with other cellulose derivatives such as cellulose triacet ate or cross-linked hydroxypropylcellulose. The films can also be appl ied to shield the surface of hollow polypropylene fibres. Unfortunatel y, this skin coating is destroyed above pH 7.5 and therefore cannot be recommended for zone electrophoresis at alkaline pH or for isoelectri c focusing.