改进的QuEChERS-GC-MS/MS检测稻谷中4种有机磷农药残留

    Detection of Four Organophosphorus Pesticide Residues in Paddy Rice by Improved QuEChERS-GC-MS/MS

    • 摘要: 建立改进的QuEChERS前处理方法结合三重四极杆气质联用仪(GC-MS/MS)测定稻谷中敌敌畏、马拉硫磷、三唑磷、毒死蜱4种有机磷农药残留量的检测方法。以稻谷为试验材料,样品采用QuEChERS前处理方法(提取前后和净化时在室温下进行)以及改进的QuEChERS前处理方法(提取前后和净化时降低样液温度)2种不同方法进行处理,在气相色谱-串联质谱多反应监测(MRM)模式下进行测定,考察4种有机磷农药的线性关系、定量限、回收率和精密度。结果表明:稻谷中4种有机磷农药在质量浓度0.005~0.5 mg·L−1范围内线性关系良好,相关系数R20.9999,检出限和定量限均能满足标准要求。在0.02、0.1、0.5 mg·kg−1 3个不同加标水平下检测马拉硫磷、三唑磷和毒死蜱3种农药残留时,采用QuEChERS前处理方法与改进的QuEChERS前处理方法的检测效果无显著差异,两种方法的重现性、检出限及回收率均能满足标准要求。而对于敌敌畏的检测,采用改进的QuEChERS前处理方法的回收率范围为75.8%~90.4%,比QuEChERS前处理方法的回收率(55.8%~62.4%)高。综上分析表明改进的QuEChERS前处理方法结合GC-MS/MS 操作方法准确度好,回收率高,更适用于稻谷中4种有机磷农药残留的检测。

       

      Abstract: An improved QuEChERS pretreatment method combined with triple quadrupole gas chromatography-mass spectrometry (GC-MS/MS) was established for the detection of four organophosphorus pesticide residues in paddy rice, including dichlorvos, malathion, triazophos and chlorpyrifos. The paddy rice was used as the experimental material, and the samples were processed by using two different pretreatment methods: the conventional QuEChERS pretreatment method (being carried out at room temperature before and after extraction, as well as during purification) and the improved QuEChERS pretreatment method (reducing the temperature of sample solution before and after extraction, as well as during purification). Then, the samples were determined by using the gas chromatography-tandem mass spectrometry (GC-MS/MS) in multiple reaction monitoring (MRM) mode to investigate the linear relationship, limit of quantitation, recovery and precision of the four organophosphorus pesticides. The results showed that the four organophosphorus pesticides in rice had a good linear relationship in the mass concentration range of 0.005−0.5 mg·L−1, with the correlation coefficient (R2) exceeding 0.9999. The detection limits and limits of quantification could meet the standard requirements. When detecting the three pesticide residues including malathion, triazophos and chlorpyrifos at three different spiked levels of 0.02,0.1,0.5 mg·kg−1, there was no significant difference in terms of the detection effect between the traditional QuEChERS pretreatment technique and the improved QuEChERS pretreatment technique. The reproducibility, detection limit and recovery rate of the two methods could meet the standard requirements. However, for the detection of dichlorvos, the improved QuEChERS pretreatment technique showed a recovery rate range of 75.8%−90.4%, which was higher than that of the conventional QuEChERS pretreatment technique (55.8%−62.4%). In summary, the improved QuEChERS pretreatment technique combined with GC-MS/MS operation method had good accuracy and high recovery rate, which was more suitable for the detection of four organophosphorus pesticide residues in paddy rice.

       

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