分散液-液微萃取-气相色谱法快速检测番茄中3种拟除虫菊酯类农药

建立了快速(quick)、简单(easy)、便宜(cheap)、有效(effective)、可靠(rugged)和安全(safe)(QuEChERS)的分散液-液微萃取(DLLME)-气相色谱快速测定番茄中拟除虫菊酯类农药残留的方法。样品经乙腈提取,N-丙基乙二胺(PSA)净化,采用DLLME富集,用气相色谱法分析。考察了联苯菊酯、甲氰菊酯和氟氰菊酯在番茄中的残留测定,同时考察了萃取剂种类与体积、分散剂体积以及萃取时间等因素对萃取效率的影响,以40 μL氯仿为萃取剂,1000 μL乙腈为分散剂,萃取时间为60 s。结果表明: 3种拟除虫菊酯类农药在番茄中的检出限分别为0.5、0.5、0.3 μg/kg。在1、10和50 μg/kg添加水平下,联苯菊酯、甲氰菊酯和氟氰菊酯在番茄中的平均回收率分别为89%～109%、92.5%～105%和90%～108%,相对标准偏差分别为2.5%～7.6%、2.8%～5.7%、3.8%～9.1%。该方法简便、快速、安全、价格低廉,重现性好,可用于番茄中拟除虫菊酯类农药的快速检测。

Rapid determination of pyrethroids in tomatoes using gas chromatography combined with dispersive liquid-liquid microextraction

An analytical method was established for the determination of three pyrethroids (bifenthrin, fenpropathrin and flucythrinate) in tomatoes using the quick, easy, cheap, effective, rugged and safe (QuEChERS) cleanup and gas chromatography. The tomato samples were extracted with acetonitrile, cleaned-up by dispersive solid-phase extraction using primary secondary amine as sorbents, concentrated by dispersive liquid-liquid microextraction (DLLME), and analyzed by gas chromatography. Factors affecting the extraction efficiency such as the type and volume of extraction solvent and the volume of dispersive and extraction time were investigated in detail. In the DLLME procedure, 40 μL chloroform was used as the extraction solvent and 1000 μL acetonitrile was used as the dispersive solvent and the extraction time was 60 s. Under the optimized conditions, the limits of detection for bifenthrin, fenpropathrin and flucythrinate were 0.5, 0.5 and 0.3 μg/kg, and the average recoveries in tomato samples at the spiked levels of 1, 10 and 50 μg/kg were 89%~109%, 92.5%~105% and 90%~108% with the relative standard deviations of 2.5%~7.6%, 2.8%~5.7% and 3.8%~9.1%, respectively. The proposed method is simple, quick, safe, reliable and applicable to analyze pyrethroid residues in tomato samples.