A new type of block copolymer, which was synthesized by styrene and maleic anhydride, P(MAn-alt-St)(119)-b-PSt(558), was successfully developed as the capillary coatings in open tubular CEC. It is interesting that the covalently bonded coatings are porous and the coatings can play the role of surfactants in the separation of aromatic amines when the buffer solution was composed of 30.0 mM ammonium acetate at pH 7.7 with 20% THF. Thus, successful baseline separation of five kinds of aromatic amines has been achieved. As validated by both artificially prepared solutions of aromatic amines and four real samples of commercially available permanent hair dyes, this proposed method was successfully applicable to the quantitative analysis of p-phenylenediamine (PPD) and o-phenylenediamine (OPD) ingredients in these commercial products, with a linear range between 8.3 microM and 6.0 mM, correlation coefficient above 0.990 and recovery between 83.5 and 110.9%. The detection limit obtained from calculations based on signal-to-noise ratio (S/N=3) was 4.2 microM for PPD and 6.0 microM for OPD, respectively. Furthermore, the role of the surfactants played by the block copolymer coatings has been primarily explored.