Synthesis of weak cation exchange/C18 bifunctional magnetic polymers for pretreatment and determination of glufosinate and its two metabolites in plasma samples.

• Synthesis of core-shell Fe 3 O 4 @WCX/C 18 in a controllable manner. • The addition of ammonium fluoride to the mobile phase effectively improved the detection sensitivity. • Bifunctional components WCX/C 18 have a synergistic effect on the purification efficiency. • Much more sensitive for GLUF and its metabolites analysis in plasma samples than the reported methods. • Confirming for GLUF poisoning based on both GLUF prototype and its two metabolites. This study focuses on the purification and detection of glufosinate (GLUF) and its metabolites N-acetyl GLUF and MPP in plasma samples. A Dikma Polyamino HILIC column was used for the effective retention and separation of GLUF and its metabolites, and the innovative addition of a low concentration of ammonium fluoride solution to the mobile phase effectively improved the detection sensitivity of the target analytes. Monodisperse core-shell weak cation exchange (WCX)/C 18 bifunctional magnetic polymer composites (Fe 3 O 4 @WCX/C 18) were prepared in a controllable manner, and their morphology and composition were fully characterized. The Fe 3 O 4 @WCX/C 18 microspheres were used as a magnetic solid-phase extraction (MSPE) adsorbent for the sample purification and detection of GLUF and its metabolites in plasma samples combined with liquid chromatography-tandem mass spectrometry (LC-MS/MS). The purification conditions of Fe 3 O 4 @WCX/C 18 microspheres for GLUF and its metabolites in spiked plasma samples were optimized to achieve the best MSPE efficiency. The purification mechanisms of the target analytes in plasma samples include electrostatic attraction and hydrophobic interactions. Furthermore, the effect of the molar ratio of the two functional monomers 4-VBA and 1-octadecene in the adsorbent was optimized and it shows that the bifunctional components WCX/C 18 have a synergistic effect on the determination of GLUF and its metabolites in plasma samples. In addition, the present study compared the purification performance of the Fe 3 O 4 @WCX/C 18 microsphere-based MSPE method with that of the commercial Oasis WCX SPE method, and the results showed that the Fe 3 O 4 @WCX/C 18 microsphere-based MSPE method established in this work had a stronger ability to remove matrix interferences. Under optimal purification conditions, the recoveries of GLUF and its metabolites in plasma were 87.6–111 % with relative standard deviations (RSDs) ranging from 0.2 % to 4.8 %. The limits of detection (LODs, S/N≥3) and limits of quantification (LOQs, S/N≥10) were 0.10–0.18 μg/L and 0.30–0.54 μg/L, respectively. The MSPE-LC-MS/MS method developed in this study is fast, simple, accurate and sensitive and can be used to confirm GLUF intoxication based not only on the detection of the GLUF prototype but also on the detection of its two metabolites. [ABSTRACT FROM AUTHOR]