A magnetic dispersive solid phase extraction method coupled with high-performance liquid chromatography was proposed for the simultaneous separation and determination of paraquat (PQ) and diquat (DQ) in human plasma and urine samples. Based on the reduction of PQ and DQ to a blue radical and yellow-green radical by sodium dithionite in an alkaline medium, a fast colorimetric method was also developed for the fast detection of PQ or DQ. In this paper, CoFe₂O₄@SiO₂ magnetic nanoparticles were used as the adsorbent for the magnetic dispersive solid phase extraction of paraquat and diquat, and these two analytes were found to be eluted directly from the adsorbent by NaOH solution. The main factors affecting the extraction efficiency including amount of extractant, extraction time, sample volume, sample solution pH, and elution volume were optimized. Under the optimized experimental conditions, the calibration curve was linear at a concentration range of 28.5–570.2 μg/L, and the correlation coefficient of paraquat and diquat was 0.9986 and 0.9980, respectively. The limits of detection of paraquat and diquat were 4.5 μg/L and 4.3 μg/L. The proposed MSPE-HPLC method was successfully applied to the detection of the paraquat and diquat in human plasma and urine with satisfied recoveries of PQ and DQ in the range of 87.5%–98.7%.

中文翻译：

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磁分散固相萃取-高效液相色谱法分离测定人血浆和尿液中的百草枯和敌草快。

提出了一种磁性分散固相萃取结合高效液相色谱的方法，用于同时分离和测定人血浆和尿液样品中的百草枯（PQ）和敌草快（DQ）。基于连二亚硫酸钠在碱性介质中将PQ和DQ还原为蓝色自由基和黄绿色自由基，还开发了一种快速比色法来快速检测PQ或DQ。本文中，CoFe ₂ O ₄ @SiO ₂磁性纳米颗粒用作百草枯和敌草快的磁性分散固相萃取的吸附剂，发现这两种分析物被NaOH溶液直接从吸附剂中洗脱出来。优化了影响萃取效率的主要因素，包括萃取剂的量，萃取时间，样品量，样品溶液的pH值和洗脱量。在优化的实验条件下，校准曲线是线性的以28.5-570.2的浓度范围 μ克/升，和百草枯和敌草快的相关系数分别为0.9986和0.9980。检测百草枯和敌草快的限为4.5  μ g / L和4.3  μ克/升 所提出的MSPE-HPLC方法已成功地用于检测人血浆和尿液中的百草枯和敌草快，PQ和DQ的回收率在87.5％–98.7％之间。