| 摘要 |
<p>The inner walls of capillary tubes being fine and of small diameter are provided with a continuous positively charged coating which is used in capillary electrophoresis and is prepared by chemical reaction between the capillary tube inner surface and a bifunctional substance. The first chemical grouping of a bifunctional substance is capable of forming a covalent bond with the capillary tube inner wall surface; the second grouping contains one or more stable, continuous positive charges, possibly in the form of quaternary ammonium. The stable, continuous, positive charge in the capillary tube inner surface coating has a twofold effect: it reverses the direction of the electroosmosis flow while at that same time increasing its value relative to non-treated capillary tubes or to negatively charged or uncharged coatings. The presence of this coating serves to separate several chemical substances at the same time which would not be possible otherwise. It also substantially reduces the adsorption of substances on the capillary tube inner walls using a mecanism different to other types of coatings which improves separation characteristics.</p> |
