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建立了一种同步检测稻田中硝磺草酮和2甲4氯残留的固相萃取-高效液相色谱-串联质谱(SPE-LC-MS/MS)分析方法。样品经乙酸乙酯提取后,用PSA吸附、C_(18)固相萃取小柱净化,C_(18)色谱柱分离,0.1%甲酸水-0.1%甲酸甲醇溶液为流动相,梯度洗脱分离,在电喷雾ESI离子源正、负离子模式下,采用质谱多反应监测(MRM)模式定性分析。结果表明:硝磺草酮和2甲4氯的检出限(LOD)分别为0.005和0.025 ng,定量限(LOQ)分别为0.01和0.05 mg/L。在0.001~2 mg/L和0.005~5 mg/L范围内,硝磺草酮和2甲4氯的质量浓度与对应的峰面积间呈良好的线性关系,其相关系数均大于0.999 7。在0.01~2 mg/L添加水平下,硝磺草酮在田水、土壤、植株、稻壳和糙米中的平均回收率为75%~103%,相对标准偏差(RSD)为0.1%~8.2%;在0.05~10 mg/L添加水平下,2甲4氯在田水、土壤、植株、稻壳和糙米中的平均回收率为90%~113%,RSD为0.5%~7.4%。说明该方法高效、快捷、精确度高,能够满足硝磺草酮和2甲4氯钠在稻田中的残留量检测分析要求。
A simultaneous SPE-LC-MS / MS method for the determination of mesotrione and 2-MCPD in paddy field was established. After the sample was extracted with ethyl acetate, it was purified by PSA adsorption, C_ (18) solid phase extraction cartridge, and separated on a C 18 column. The mobile phase consisted of 0.1% formic acid and 0.1% formic acid in methanol, The electrospray ionization (ESI) ion source positive and negative ion modes were qualitatively analyzed by mass spectrometry multiple reaction monitoring (MRM) mode. The results showed that the limits of detection (LOD) of mesotrione and 2-methyl-4-chloro were 0.005 and 0.025 ng, respectively, and the limits of quantitation (LOQ) were 0.01 and 0.05 mg / L, respectively. In the range of 0.001-2 mg / L and 0.005-5 mg / L, the concentrations of mesotrione and MCPA showed a good linear relationship with the corresponding peak area, and the correlation coefficient was greater than 0.999 7. The average recoveries of mesotrione in field water, soil, plant, rice husk and brown rice ranged from 75% to 103% with relative standard deviations (RSDs) from 0.1% to 8.2 at 0.01-2 mg / L %. The average recoveries of MCPA in field water, soil, plant, rice husk and brown rice ranged from 90% to 113% and RSD from 0.5% to 7.4% at 0.05-10 mg / L. This method is efficient, rapid and accurate. It can meet the requirements of mesotrione and 2-methyl-4-chloro-sodium residue in paddy field.