title: Physicochemical and chromatographic characteristics of random amphiphilic copolymer aggregation in electrokinetic chromatography.
abstract: The random amphiphilic polymeric aggregation, self-assembled from poly (methyl methacrylate-co-methacrylic acid) (P(MMA-co-MAA)), was explored as a novel pseudostationary phase (PSP) in electrokinetic chromatography (EKC) in our previous report. This work focused on physicochemical characteristics and PSP performances of the polymeric aggregations. The physicochemical characteristics of polymeric aggregations, including critical aggregation concentration (CAC), zeta potential, hydrodynamic diameter, and micropolarity were determined. Experimental results showed that polymeric aggregations had much lower CAC, which decreased the usage of copolymer in EKC, weakened ionic strength and shortened analysis time. The monomer molar ratio of the copolymer was a key factor for physicochemical characteristics and PSP performances of the polymeric aggregations. With the increase of the hydrophobic monomer molar ratio, CAC, micropolarity and dimension of polymeric aggregation decreased significantly while zeta potentials were similar. Correspondingly, separation window enlarged and methylene selectivity evaluated with six kinds of n-alkylphenone homologous series enhanced. Linear solvation energy relationships (LSER) analysis found that hydrophobic interaction is the most important interaction between analytes and polymeric PSPs. Compared with SDS micelle, polymeric aggregations owned more types of interactions, such as stronger hydrogen bonding and relative larger dipole interaction, which provided a bigger adjustment room to improve PSP selectivity.
authors.affiliation: School of Chemical and Material Engineering, Jiangnan University; Ministry of Education, Wuxi 214122, P. R. China.
authors.forename: Xinjiong
authors.initials: X
authors.lastname: Ni
authors.affiliation: School of Chemical and Material Engineering, Jiangnan University; Ministry of Education, Wuxi 214122, P. R. China.
authors.forename: Xiaolu
authors.initials: X
authors.lastname: Zhuo
authors.affiliation: School of Chemical and Material Engineering, Jiangnan University; Ministry of Education, Wuxi 214122, P. R. China.
authors.forename: Xiaojin
authors.initials: X
authors.lastname: Xu
authors.affiliation: School of Chemical and Material Engineering, Jiangnan University; Ministry of Education, Wuxi 214122, P. R. China; The Key Laboratory of Food Colloids and Biotechnology, Ministry of Education, Wuxi 214122, P. R. China. Electronic address: yuhuacao64@gmail.com.
authors.forename: Yuhua
authors.initials: Y
authors.lastname: Cao
authors.affiliation: School of Chemical and Material Engineering, Jiangnan University; Ministry of Education, Wuxi 214122, P. R. China.
authors.forename: Guangqun
authors.initials: G
authors.lastname: Cao
mesh_terms: D020374:Chromatography, Micellar Electrokinetic Capillary / Q000379:methods*; D006860:Hydrogen Bonding; D057927:Hydrophobic and Hydrophilic Interactions; D008823:Micelles; D011109:Polymethacrylic Acids / Q000737:chemistry*; D014783:Viscosity
chemical_list: D008823:Micelles; D011109:Polymethacrylic Acids; C038300:methylmethacrylate-methacrylic acid copolymer
keywords: Linear solvation energy relationships; Methylene selectivity; Microstructure; Monomer molar ratio; Pseudostationary phase; Random copolymer aggregation