Preparation and Application of Weak Cation Exchange Resin Based on Thiol Click Reaction

ABSTRACT Using poly(styrene‐divinylbenzene) microspheres as stationary phase matrix and mercaptosuccinic acid as a modifier, a new weak cation exchange resin was synthesized by thiol click reaction. The conditions for thiol‐chlorine click reaction and thiol‐alkene click reaction were optimized. The surface morphology and chemical composition of the modified microspheres were characterized by scanning electron microscopy, Fourier‐transform infrared spectroscopy, and an elemental analyzer. The stationary phase can achieve the separation of six common cations within 25 min. A homemade weak cation chromatographic column was used to determine the impurities of Na + and K + and the content of tetramethylammonium ions in tetramethylammonium hydroxide samples. The method showed a good linear correlation in the range of 0.1–500.0 mg/L with correlation coefficients of 0.9998–0.9999, and the limits of detection (signal‐to‐noise ratio ≥ 3) were 0.01–0.20 mg/L. The intra‐day relative standard deviations (RSDs) were in the range of 1.1%–4.4%, and the inter‐day RSDs were in the range of 0.8%–14.8%. The spiked recoveries were in the range of 91.92%–119.86%. The results showed that the prepared stationary phase exhibited effective separation ability and good reproducibility, which was suitable for the analysis of the impurities of Na + , K + , and the content of tetramethylammonium in the tetramethylammonium reagents.