Preparation and Characterization of Quaternized Polystyrene-Divinylbenzene Stationary Phases in Deep Eutectic Solvents for Anion-Exchange Chromatography

In this study, quaternized cationic polyelectrolytes were successfully decorated on polystyrene-divinylbenzene (PS-DVB) microspheres in deep eutectic solvents (DESs). Quaternized cationic polyelectrolytes and hyperbranched layers were prepared using 1,4-butanediol diglycidyl ether (BDDE) and methylamine (MA) as monomers. The effects of different reaction solvents, the amount of agglomerated polyelectrolytes, and the number of hyperbranched layers on the chromatographic performance of the stationary phase were investigated. The surface morphological feature and chemical composition of the PS-DVB microspheres were characterized by SEM, FT-IR, and elemental analysis. The results showed that the optimized anion exchanger had a good chromatographic performance by choosing a mixture of 2.0 mmol/L sodium carbonate and 2.0 mmol/L sodium bicarbonate as the mobile phase at a flow rate of 1.0 mL/min. Seven common anions (fluoride ion, chloride ion, nitrite ion, bromide ion, nitrate ion, phosphate ion, and sulfate ion) were well separated within 25 min. The average numbers of theoretical plates per meter for three batches of columns prepared in DESs increased by 5% ~ 20%, as compared with those of the columns prepared in deionized water. Additionally, the asymmetry factors of detected anions were also improved for the columns prepared in DESs.