The main factor that influences separation efficiency and reproducibility of the protein separations by capillary electrophoresis (CE) is protein adsorption .Several methods involved in this process

including buffer pH

small molecule additives

modification of the capillary inner-wall

were discussed in this review .The focus of this review is to introduce and compare recent advances of two major classes of wall coatings for capillary ———covalently linked polymeric coatings and physically adsorbed polymeric coatings

which were used to eliminate electroosmotic flow ( EOF)

tune EOF and prevent protein adsorption .Comparison of performance between these two coatings was also involved in this review .In General

physically adsorbed polymeric coatings are becoming more and more popular owing to its several distinct advantages over covalently linked polymeric coatings .Although great progress has been made

there is still no universal wall coating which can function well for all types of protein analysis .The separation of complex protein samples will still be a challenge .