A block copolymer covalent coating acting as surfactants in separation of 2-[hydroxy(4-nitrophenyl)methyl]-cyclopent-2-enone and 4-nitrobenzaldehyde by capillary electrophoresis

An innovative block copolymer capillary coating P(MAn-alt-St)127-b-PSt592, synthesized by maleic anhydride and styrene, was developed as a new kind of coating for capillary electrophoresis. The covalent bond coating was effectively applied in the separation of raw material (4-nitrobenzaldehyde) and production (2-[hydroxy(4-nitrophenyl)methyl]-cyclopent-2-enone) in a Baylis–Hillman reaction using ammonium acetate with 20% tetrahydrofuran (v/v) as the buffer solution. Electroosmotic flow measurement gave an instantly stable value after 70 times continued injection in 5 days and showed that P(MAn-alt-St)127-b-PSt592 coatings could suppress electroosmotic flow effectively compared with the bare capillary. The effects of tetrahydrofuran and the pH of buffer on the separation were investigated. The characteristics of the coatings to form micelles similar to surfactants were detected by atomic force microscopy. Moreover, the superiority of this coating was further applied in the separation of four aromatic amines.