Fuente: Journal of applied polymer Lugar: RESEARCH ARTICLE Poly(aniline-co-3-aminobenzoic acid) copolymers are synthesized with controlled composition and correlated with UV–Vis spectral characteristics. A rapid approach for composition determination is proposed and linked to protein sorption behavior. Copolymers containing ≥ 30 mol% 3-aminobenzoic acid exhibit selective retention of proteins according to their isoelectric points, enabling the development of sorption-active and electrochemical sensing materials.

ABSTRACT
The dependence of the structure of optical absorption spectra of solutions of copolymers of aniline with 3-aminobenzoic acid, synthesized by oxidative polymerization, on the composition of the initial reaction mixture and reaction conditions was investigated. Optimal conditions for the formation of coatings based on the obtained copolymers on the surface of glass plates and synthetic membranes were determined. A correspondence coefficient of the spectral structure to the composition of the initial reaction mixture and to the composition of the resulting copolymers was determined. The sorption properties of coatings based on the synthesized copolymers in relation to model proteins with different isoelectric points were evaluated. Based on the obtained data, a protocol for rapid determination of copolymers composition using the characteristics of absorption spectra of their solutions was proposed. An algorithm for correlation of the sorption properties of the copolymer coatings toward proteins with the chemical composition of the corresponding copolymers was developed. It was established that the presence of a certain amount of carboxyl groups in the copolymer composition ensures selective binding of proteins depending on the pH of the medium, which opens prospects for the application of materials containing such coatings in analytical biotechnology and molecular diagnostics.