QuEChERS-超高效液相色谱串联质谱法同时测定土壤中5种常用除草剂

建立了超高效液相色谱串联质谱法(UPLC-MS/MS)简单、快速、灵敏、准确地同时测定土壤中5种常用除草剂多残留量的方法。样品经改进的QuEChERS(快速、简单、廉价、高效、灵活和安全)方法一步完成萃取净化,未使用缓冲盐溶液,经乙腈萃取,N-丙基乙二胺(PSA)和C18吸附剂填料净化,离心后直接过膜上机检测,萃取和净化的效果满足检测要求。UPLC-MS/MS方法采用Waters ACQUITY UPLCTMBEH C18(50 mm×2.1 mm i.d.,1.7 mm)色谱柱,柱温30℃,流动相为甲醇和水,梯度洗脱,流速0.25 mL/min,电喷雾电离源正离子(ESI+)多反应监测(MRM)模式检测,外标法定量。5种常用除草剂在0.5~200 mg/L范围内线性关系良好,相关系数为0.9947~0.9984。在4和40 mg/kg水平下的平均加标回收率为75.4%~98.5%;相对标准偏差为3.2%~11.8%;方法的检出限(S/N=3)为0.005~0.020 mg/kg,定量限(S/N=10)为0.017~0.067 mg/kg。

QuEChERS-Ultra-Performance Liquid Chromatography Tandem Mass Spectrometry for Determination of Five Currently Used Herbicides

A simple, rapid, sensitive and accurate ultra-performance liquid chromatography-tandem mass spectrometric (UPLC-MS/MS) method was developed for the simultaneous determination of five currently used herbicides in soil. The sample preparation using the modified QuEChERS (quick, easy, cheap, effective, rugged and safe) method completed the extraction and clean-up steps in one procedure. In this none buffer QuEChERS method, samples were extracted with acetonitrile, cleaned up with primary secondary amine (PSA) and C₁₈ sorbent and then centrifugated and filtrated before detection. The UPLC-MS/MS method was performed on Waters ACQUITY UPLC™ BEH C₁₈ (50 mm × 2.1 mm i.d., 1.7 μm) at a column temperature of 30 °C, with the gradient elution with methanol and pure water as the mobile phase at a flow rate of 0.25 mL min⁻¹. The positive electrospray ionization (ESI⁺) source under the multiple reaction monitoring (MRM) mode and external standard method were used for quantification. The linear range was shown to be from 0.5 to 200 μg L⁻¹ with a correlation coefficient of 0.9984. The limits of detection (LOD) were in the range of 0.005–0.020 μg kg⁻¹ (S/N = 3) and the limits of quantification (LOQ) were in the range 0.017–0.067 μg kg⁻¹ (S/N = 10). The method was validated with soil samples spiked at two fortification levels (4 and 40 μg kg⁻¹) and recoveries were in the range 75.4%–98.5% with relative standard deviations (RSD) of 3.2%–11.8%.