加速溶剂萃取GC-NCI-MS法测定糙米中氯硝胺残留量

[目的]建立一种采用加速溶剂萃取和气相色谱-质谱测定糙米中氯硝胺残留量的分析方法。[方法]试样采用丙酮-正己烷(体积比1∶2)萃取,中性氧化铝固相萃取小柱净化。用HP-FFAP石英毛细管柱程序升温分离,GC-NCI-MS的选择离子监测方式(SIM)测定,外标法定量。并对提取溶剂、萃取温度、不同冲洗体积、静态萃取时间和循环次数等试验条件进行优化。[结果]当添加水平为1、2、10、20、100μg/kg时,方法回收率为93.6%～102.8%,相对标准偏差为2.2%～6.2%,检出限是1μg/kg。采用保留时间和选择监视离子丰度比对阳性样品进行确证,加速溶剂萃取法和固相萃取技术净化糙米中氯硝胺减少了分析时间和溶剂消耗。[结论]试验成功建立了GC-NC-MS的选择离子监测的测定方法测定糙米中氯硝胺残留量,有效地减少基质杂质对分析灵敏度和方法检出限的影响,提高了检测方法的特异性。

Detection of Dicloran Residue in Crude Rice by the Combination of Accelerated Solvent Extraction and GC-NCI-MS

[Objective] To establish a new method of accelerated solvent extraction and gas chromatography mass spectrography to determine the dicloran residue in brown rice.[Method] The sample was extracted by hexane-acetone(1∶2 by volume),purified by neutral alumina solid phase extraction column,separated by HP-FFAP silica capillary column with temperature programmed,assessed by GC-NCI-MS in selected ion monitoring mode(SIM),and quantified by external standard.The experimental conditions including extraction solvent,extraction temperature,different flush volume,static extraction time and cycle number have been optimized.[Result] When the adding level is 1,2,10,20,100 μg/kg,the method recovery is 93.6%-102.8%;the relative standard deviation is 2.2%-6.2% and the detection limit is 1 μg/kg.The result was determined by comparison to positive sample with retention time and selectively monitoring ion abundances.The accelerated solvent extraction and GC-NCI-MS method purified the brown rice and reduced the analytic time and solvent consumption.[Conclusion] The experiment successfully established a GC-NC-MS method for determining the dicloran residue in brown rice,which effectively reduces the impact of impurities on the sensitivity of analysis and the detection limit of the method,and improves the specificity of the detection method.