气相色谱-四极杆/飞行时间质谱法快速筛查茶叶中350种农药残留

Rapid screening of 350 pesticide residues in tea by gas chromatagraphy coupled with quadrupole time-of-flight massspectrometry

建立了气相色谱-四极杆/飞行时间质谱(GC-Q-TOF/MS)快速筛查茶叶中350种农药残留的方法。样品经饱和食盐水浸润后以乙腈提取,以无水氯化钙去除水分及沉淀酚类,经石墨化炭黑(GCB)和N-丙基乙二胺(PSA)分散固相净化,GC-Q-TOF/MS测定。采用精确质量数据库和谱图库检索的方式进行筛查与确证,以检索得分≥70的最低浓度作为方法的筛查限,结果表明99.3%农药能够在一律标准(10.0μg/kg)下定性检出;在10,50,100μg/kg 3个加标水平,目标农药的平均回收率分别为43.5%~136.7%,46.3%~132.6%,49.2%~135.3%,相对标准偏差(RSD)均小于20%(n=6)。该方法适用于茶叶中农药残留的高通量快速筛查。

A method for rapid screening of 350 pesticide residues in tea by gas chromatography coupled with quadrupole time-of-flight mass spectrometry(GC-Q-TOF/MS)was developed.The analytes were extracted from tea soaking with saturated brine by using acetonitrile,the anhydrous calcium chloride(CaCl2)was employed to dehydrate and precipitate phenols and organic acids,purified with graphitic carbon black(GCB)and N-propyl ethylenediamine(PSA),and determined by GC-Q-TOF/MS.Screening and confirmation was achieved by accurate mass database and library search,and the minimum concentration with a score(≥70)was used as the screening limit of the method.99.3%of the pesticides could be qualitatively detected under the standard(10.0μg/kg).At the spiked levels of 10,50 and 100μg/kg,the average recoveries of 350 pesticide compounds ranged from 43.5%to 136.7%,46.3%to 132.6%and 49.2%to 135.3%,respectively,with all the relative standard deviations(RSDs)less than 20%(n=6).The results showed that the method could be used for high-throughput rapid detection of pesticides in tea.