摘要
采用QuEChERS前处理技术,结合内标前置法建立了气相色谱-串联质谱同时检测茶叶中37种农药残留的方法,待测农药包括14种有机磷类、10种有机氯类、8种拟除虫菊酯类和5种有机杂环类。比较了提取溶剂、加水量、内标放置方式对37种农药提取效果的影响,考察了不同类型茶叶的基质效应,确定最优的实验条件为:茶叶样品加入内标后,加水浸泡,经乙腈超声提取,QuEChERS法净化,采用气相色谱-串联质谱仪多反应离子监测模式(MRM)进行检测,基质匹配标准曲线内标法定量。结果表明:内标前置法比内标后置法的回收率高,绿茶、红茶、白茶、黑茶基质均以基质增强效应为主。在优化实验条件下,37种农药在相应的质量浓度范围内呈良好的线性关系,相关系数(r^(2))均大于0.99。方法检出限(LOD)为0.2~15.7μg/kg,定量下限(LOQ)为0.7~52.2μg/kg。37种农药在LOQ、2LOQ和10LOQ 3个加标水平下的回收率为70.2%~120%,相对标准偏差(RSD)为1.1%~11%。该方法操作简单、准确高效、成本较低,适用于茶叶中农药多残留的日常检测。
A gas chromatography-tandem mass spectrometry(GC-MS/MS)combined with QuEChERS plus prepositive internal standard was developed for the simultaneous detection of 37 pesticide residues in tea.The target pesticides included 14 organophosphorus pesticides,10 organochlorine pesticides,8 pyrethroid pesticides and 5 organic heterocyclic pesticides.The effects of different extraction solvents,water amounts and internal standard adding approaches on extraction were studied.The matrix effects of 37 pesticides in different types of tea were also explored.The optimal experimental conditions were as follows:firstly,the tea samples were soaked for 30 min with 10 mL water after adding heptachlor epoxide as internal standard,then the target pesticides were extracted ultrasonically using 20 mL acetonitrile for 20 min,followed by adding QuEChERS extract pouch(containing 6 g magnesium sulfate and 1.5 g sodium acetate).After vortexing evenly and centrifugation,10 mL of the supernatant was separated and transferred into QuEChERS purge tube which contained a mixed sorbent of 1 200 mg magnesium sulfate,400 mg primary secondary amine(PSA),400 mg C_(18) and400 mg graphitized carbon black(GCB).The mixtures were vortexed evenly and centrifugated.Then 2 mL of the purified solution was concentrated by nitrogen blowing at 40 ℃ until the solution was nearly desiccated.After that,1 mL ethyl acetate was used to redissolve the residues.Finally,the target pesticides were detected by GC-MS/MS in multiple reaction monitoring(MRM)mode,and quantified by the internal standard method with matrix matching standard curve.The results showed that the use of prepositive internal standard had a better recovery result than the use of postpositive internal standard.Chromatogram signals of most pesticides in green tea,black tea,white tea and dark tea matrices were enhanced distinctly.Under the optimized conditions,good linear relationships were observed for the 37 pesticides,and the correlation coefficients(r^(2))were greater than 0.99.The limits of detection(LODs)and the limits of quantitation(LOQs)were in the range of 0.2-15.7 μg/kg and 0.7-52.2 μg/kg,respectively.The recoveries for 37 pesticides at three spiked levels(the LOQ,2 times the LOQ and 10 times the LOQ)ranged from 70.2%to 120%,with relative standard deviations(RSDs)of 1.1%-11%.This method has the features of simple operation,high accuracy,high efficiency and low cost,which could be applied to the routine detection of pesticide residues in tea.
作者
黄微
马玉凤
孟怡璠
李崇勇
李春梅
李婷
王俣心
丁伟
HUANG Wei;MA Yu-feng;MENG Yi-fan;LI Chong-yong;LI Chun-mei;LI Ting;WANG Yu-xin;DING Wei(Hanzhong Food and Drug Supervision,Inspection and Testing Center,Shaanxi Tea Products Quality Supervision and Inspection Center,Hanzhong 723000,China;Chenggu Food and Drug Inspection and Testing Center,Hanzhong 723200,China)
出处
《分析测试学报》
CAS
CSCD
北大核心
2022年第8期1221-1228,共8页
Journal of Instrumental Analysis
基金
陕西省市场监督管理局科技项目(2020KY20,2021KY23)。
关键词
气相色谱-串联质谱
QUECHERS
内标前置
茶叶
农药残留
gas chromatography-tandem mass spectrometry(GC-MS/MS)
QuEChERS
preposi⁃tive internal standard
tea
pesticide residues
