UPLC-MS/MS法测定糙米和稻壳中吡唑醚菌酯残留

Determination of Pyraclostrobin Residues in Brown Rice and Rice Husk by Ultra Performance Liquid Chromatography-tandem Mass Spectrometry

建立了超高效液相色谱-串联质谱（UPLC-MS／MS）法测定糙米和稻壳中吡唑醚菌酯残留的方法。样品中吡唑醚菌酯经乙腈水溶液提取、弗罗里硅土柱净化后，以C18反相柱为分析柱，甲酸水溶液-甲醇为流动相，在多反应监测模式下进行质谱检测，采用电喷雾正离子源，外标法定量。吡唑醚菌酯在0．02～0．50mg/L范围内与峰面积呈良好线性关系，线性方程为：Y=77425x＋630．82，相关系数的平方为0．9979。向空白糙米、空白稻壳中分别添加吡唑醚菌酯标样，使其添加量分别为0．02、0．05、0．10mg／kg时，平均回收率分别为84．7％～101．0％和86．2％～102．5％，相对标准偏差分别为3．7％～4．9％和5．8％～8．1％。糙米和稻壳中吡唑醚菌酯的最低检9n,4限均为0．2μg/kg。该方法的灵敏度和准确度都较高，适合于糙米和稻壳中吡唑醚菌酯的残留分析。

The method of determining the pyraclostrobin residues in brown rice and rice husk by uhraperfor- mance liquid chromatography- tandem mass spectrometry（ UPLC -MS/MS）was established. The pyraclostrobin resi- dues in samples were extracted with aqueous acetonitrile, and cleaned up on a florisil column , and cleaned up on a florisil column, then separated by the C18 reverse phase column using aqueous methanol and methanoic acid as mobile phase. The pyraclostrobin was detected by MS with electrospray positive ionization source under a multiple reaction monitoring mode, and quantified by external standard method. An excellent linear relationship between pyraclostrobin concentration（x） in the range of 0.02 - 0.50 mg/L and peak area（y） was achieved. The linear equation was y = 77 425x ＋ 630.82, and the square of correlation coefficient was 0.997 9. Add pyraclostrobin samples separately into the blank brown rice and rice husk,and when the additive amount were separately 0.02,0.05 and 0.10 mg/kg,the average recovery were 84.7% to 101.0%, and 86.2% to 102.5%. The relative standard deviation were separately 3. 7%-4.9% ,and 5.8%-8.1%. The limit of detection for both the brown rice and rice husk was 0.2 μg/kg. The sensitivity and accuracy of this method were relatively higher, which was applied for the determination of pyraclostrob- in residues in brown rice and rice husk.