固相萃取-气相色谱-质谱联用法测定黄瓜和番茄中毒氟磷的残留及其裂解机理

建立了黄瓜和番茄中毒氟磷残留量的固相萃取-气相色谱-质谱联用(SPE-GC-MS)分析方法;对毒氟磷的裂解机理进行了探讨,确定了测试分析的定性离子和定量离子。样品采用V(正己烷):V(丙酮)=1:1混合液高速匀浆提取,使用以N-丙基乙二胺(PSA)、C18和石墨化炭黑(GCB)的混合物为填料的固相萃取柱净化,采用气相色谱-质谱联用仪在选择离子扫描(SIM)模式下进行检测,外标法定量。结果显示,毒氟磷在0.01~0.5 mg/L内,标准溶液的峰面积与质量浓度的线性关系良好(r≥0.999),方法的检出限(LOD)(S/N=3)为0.003 mg/kg,定量限(LOQ)(S/N=10)为0.01 mg/kg。在0.01、0.02和0.1 mg/kg添加水平下,毒氟磷的平均回收率为99.9%~100.2%,相对标准偏差(RSD,n=6)为0.97%~3.07%。

Determination of Dufulin residues in cucumber and tomato by gas chromatography-mass spectrometry with solid phase extraction and its fragmentation mechanism

A solid phase extraction coupled with gas chromatography-mass spectrometric(SPE-GC-MS) method was established for the determination of Dufulin residue in cucumber and tomato.After extracted with V(n-hexane):V(acetone)=1:1 mixture in high-speed homogenized extract method,the target samples were cleaned up in solid phase extraction by the mixture of N-propylethylenediamine(PSA),C₁₈ and graphitized carbon(GCB),analyzed by GC-MS under selected ion monitor mode(SIM) and quantified by the external standard method.Good linear between the peak area and the concentration of Dufulin was obtained in the range of 0.01-0.5 mg/L with correlation coefficient not less than 0.999 under the optimum conditions,the limit of detection(LOD)(S/N=3)was 0.003 mg/kg and the limit of quantitation(LOQ)(S/N=10) was 0.01 mg/kg.The average recoveries of Dufulin from the cucumber and tomato blank samples at three spiked levels of 0.01,0.02 and 0.1 mg/kg ranged from 99.9% to 100.2% with RSD of 0.97%-3.07%.The fragmentation mechanism of Dufulin was also studied in which the qualitative ions and quantitative ions were confirmed.