超高效液相色谱-串联质谱法测定水稻中噁唑酰草胺残留量

建立了检测水稻植株、稻壳、糙米、田水基质中噁唑酰草胺残留量的超高效液相色谱-串联质谱(UPLC-MS/MS)的分析方法。待测样品经乙腈匀浆提取、经PSA净化后,经ACQUITY UPLC BEH C₁₈色谱柱(50 mm×2.1 mm,1.7 μm)分离,以甲醇-水为流动相梯度洗脱,采用电喷雾电离串联质谱正离子多反应检测(MRM)模式测定,外标法定量。结果表明：噁唑酰草胺在0.001~0.05 μg/mL浓度范围内,在水稻植株、糙米、稻壳、田水基质中,供试农药的质量浓度与其相应的峰面积间呈良好线性相关,相关系数(r)分别为0.998、0.996、0.994和0.996;在0.005、0.05、0.5 mg/kg 3个水平下进行添加回收试验,噁唑酰草胺在水稻植株、稻壳、糙米、田水基质中的回收率分别在85.8%~114.6%、80.6%~106.4%、84.2%~95.0%和92.8%~109.3%之间,相对标准偏差(RSD)分别在2.7%~6.7%、3.8%~9.2%、2.9%~4.6%和5.0%~12.3%之间,定量限(LOQs)为0.005 mg/kg。该方法简单、快速、准确、灵敏,所得结果满足农药残留检测的要求,适用于水稻植株、糙米、稻壳、田水中噁唑酰草胺的残留检测。

Determination of Metamifop Residue in Rice by UPLC-MS/MS

An ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method to detect metamifop residue in rice plant, rise husk, brown rice and rice field water was established, the samples were extracted with acetonitrile, and cleaned up by PSA, separated by ACQUITY UPLC BEH C₁₈ column (50 mm×2.1 mm, 1.7 μm) and gradient eluted with methanol-water, detected with multiple reaction monitoring (MRM) modes with electrospray ionization and then quantified with external standard method. The results showed that a good linear relationship in the range of 0.005-0.05 μg/mL was found of metamifop with rice plant, brown rice, rise husk and rice field water, with the correlation coefficients (r) of 0.998, 0.996, 0.994 and 0.996, respectively. The method was validated at three spike levels (0.005, 0.05 and 0.5 mg/kg), the average recoveries were 85.8%-114.6%, 80.6%-106.4%, 84.2%-95.0% and 92.8%-109.3% in rice plant, rise husk, brown rice and rice field water, with RSD of 2.7%-6.7%, 3.8%-9.2%, 2.9%-4.6% and 5.0%-12.3%, respectively. The limit of quantization (LOQs) was 0.005 mg/kg. This method could meet the determination requirements, and it was simple, quick, accurate and sensitive, could be used to study the residues of metamifop in rice.