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建立使用一种萃取头同时检测蔬菜中30种农药的GC-MS分析方法。采用了SPME-GC/MS自动进样技术,比较聚二甲基硅氧烷(PDMS)、聚丙烯酸酯(PA)、聚二甲基硅氧烷-二乙烯基苯(PDMS/DVB)、聚乙二醇-二乙烯基苯(CW/DVB)4种固定相涂层的分析效果,选择了目标物萃取效率较高、干扰物萃取较少的PDMS。通过正交实验设计,选择不同的萃取温度、萃取时间、振荡速度进行试验,最终确定振荡速度250 r/min,萃取温度70℃,萃取时间60 min作为萃取条件。对不同的无机盐浓度对标准品溶液和加入基质标准品溶液的提取效率的影响分别进行了试验,确定用10%(w/V)NaCl溶液增加提取液离子强度。试验过程中优化分析的色谱条件和质谱条件,进样到分析结束时间可控制在40 min。该方法检测蔬菜样品中混合标准溶液的回收率为43%～119%,相对标准偏差在3.4%～19%之间。
A GC-MS method for simultaneous determination of 30 pesticides in vegetables using an extraction head was established. The use of SPME-GC / MS autosampler technology to compare polydimethylsiloxane (PDMS), polyacrylate (PA), polydimethylsiloxane- divinylbenzene (PDMS / DVB), poly Ethylene glycol-divinylbenzene (CW / DVB) four kinds of stationary phase coating analysis results, select the target extraction efficiency is higher, interfere with the extraction of less PDMS. Orthogonal experimental design was adopted to select different extraction temperature, extraction time and oscillation speed. The final determination of the oscillation speed was 250 r / min, the extraction temperature was 70 ℃ and the extraction time was 60 min as the extraction conditions. The influence of different inorganic salt concentration on the extraction efficiency of standard solution and matrix standard solution were tested respectively, and the ionic strength of the extract was determined by using 10% (w / v) NaCl solution. Optimization of the chromatographic conditions and mass spectrometry conditions during the test, injection time to the analysis can be controlled at 40 min. The method was applied to detect the recovery of mixed standard solution in vegetable samples from 43% to 119% with the relative standard deviation of 3.4% to 19%.