Coated Capillary Electrophoresis Tubes and System

Abstract

The invention is directed to a capillary tube for electrophoresis that has a positively charged coating on the capillary inner surface that prevents positively charged analytes from adsorbing to the inner capillary surface. The capillary tube has an inner surface that is coated with a first polymer layer having a plurality of polymer groups comprising polyethylene imine, designated herein as (CH 2 CH 2 NH) X . The inner surface of the capillary typically has a second polymer layer covalently bonded to the first polymer layer. The invention includes a capillary tube where two or more than two polymer groups are covalently bonded to each other by a cross-linker. Also provided are an electrophoresis system the uses the coated capillary tubes, a method of performing electrophoresis that utilizes the coated capillary tubes, and a process for preparing the coated capillary tubes.

What is claimed is: 
     
         1 . A process for the preparation of a surface comprising:
 a) treating the surface with a base;   b) treating the surface with a solution containing between 2% and 30% trimethoxysilylpropyl (polyethyleneimine) to form a polymer group;   c) rinsing the surface; and   d) treating the surface with a cross-linker to cross-link at least one polymer group.   
     
     
         2 . A process for the preparation of a silica capillary tube with a coating comprising the steps of:
 a) treating the inner surface of the silica capillary tube with a base;   b) treating the inner surface of the capillary tube with a solution containing between 2% and 30% trimethoxysilylpropyl (polyethyleneimine) to form a polymer group;   c) rinsing the inner surface of the capillary tube; and   d) treating the inner surface with a cross-linker to cross-link at least one polymer group.