AB DIBLOCK COPOLYMER NANOPARTICLES VIA RAFT-MEDIATED POLYMERIZATION AS A PSEUDOSTATIONARY PHASE FOR ELECTROKINETIC CHROMATOGRAPHY

Andre Umansky, The University of Montana

Abstract

Electrokinetic chromatography (EKC) is a powerful analytical technique where analytes are separated according to their interactions with the pseudostationary and mobile phases within an electric field. Pseudostationary phases (PSPs) are an integral part of EKC and currently there are a limited number of PSPs available. As the fields of medicinal, environmental, and forensics chemistry grow, the necessity for PSPs with varied selectivity and high efficiencies becomes apparent. Until recently, polymeric synthesis of novel PSPs has been difficult due to the lack of control in structure and size distribution. Recent developments in polymeric synthesis, utilizing the Reversible addition−fragmentation chain-transfer polymerization (RAFT) process, have overcome the aforementioned problems. This study furthers the research of latex nanoparticles as PSPs. 2-Acrylamido-2-methylpropane sulfonic acid (AMPS) was chosen as a novel ionic nanoparticle shell due to its high acidic character. Butyl acrylate was chosen for the hydrophobic core to stay consistent with previous work. Through the RAFT process, nanoparticles were successfully synthesized, demonstrating size control of both the hydrophilic block and hydrophobic block. The novel PSP performance was characterized in EKC by obtaining its electrophoretic mobility (ìep) with respect to size and pH. Retention and selectivity were characterized by linear solvation energy relationships (LSER) and compared with currently used PSPs.