【作者】 曾小星；

【导师】 万益群； 谢明勇；

【作者基本信息】 南昌大学 ， 分析化学， 2008， 硕士

【摘要】 茶叶是直接泡饮的食品,其卫生质量与人类健康息息相关。近年来,为限制滥用农药,维护人民利益,国内外市场都加强了对茶叶卫生质量的监测,对茶叶中的各类农药残留也提出了越来越苛刻限量要求。目前研究报道的茶叶中农药残留的分析方法比较多,但大多是单一种类农药的分析,且前处理技术也较为繁琐,多种类型农药残留同时检测的方法报道较少。本论文针对茶叶中农药残留国内外研究现状,应用一些现代的提取及分析技术,对茶叶中的多种类型的农药残留的分析新方法进行了系统的研究。其主要研究成果如下:1.建立了超声波提取-气相色谱法同时测定茶叶中18种有机氯和9种拟除虫菊酯类农药残留的分析新方法。以正已烷-二氯甲烷(1:1,v/v)为提取剂,在超声波下提取茶叶中的有机农药残留,提取液用弗罗里硅土和中性氧化铝混合层析柱净化,用GC-ECD法同时测定。有机氯农药在0.001～0.2 ug/mL范围内、拟除虫菊酯类农药在0.005～1.0 ug/mL范围内线性良好。有机氯农药在0.04ug/mL和0.01 ug/mL两个水平添加时的回收率(n=6)分别为89.5%～118.2%和80.0%～112.7%,相对标准偏差分别为3.82%～9.64%和4.26%～11.78%;拟除虫菊酯在0.20 ug/mL和0.05 ug/mL两个水平添加时的回收率(n=6)分别为97.5%～129.6%和87.3%～110.1%,相对标准偏差分别为3.78%～10.72%和3.02%～13.84%。该方法的检出限:有机氯农药为0.0004～0.0010 ug/mL,拟除虫菊酯农药为0.0025～0.0050 ug/mL,用于江西茶叶中多种农药残留测定,结果满意。2.建立了微波辅助萃取-气相色谱法同时测定茶叶中27种有机氯和拟除虫菊酯农药残留的分析新方法。以正已烷-二氯甲烷(1:2,v/v)为提取剂,应用微波辅助技术对茶叶样品进行提取,并用正交设计法对微波萃取条件进行了优化。在0.4 mL、0.2 mL、0.1 mL(0.2 ug/mL有机氯农药+1.0 ug/mL拟除虫菊酯农药)三个水平添加时的平均回收率(n=5)分别为80.9%～118.5%、88.4%～120.7%、80.9%～116.3%;相对标准偏差分别为1.61%～6.70%、1.89%～6.49%、1.98%～11.87%。本方法快速、灵敏、准确、可靠,用于江西茶叶样品中有机农药残留测定,取得了较好的效果。3.建立了气相色谱-质谱法同时测定茶叶中有机氯、有机磷、氨基甲酸酯和拟除虫菊酯等22种农药残留的分析新方法。在超声波辅助下,用乙腈-丙酮(7:3,v/v)提取茶叶样品中的农药残留,并用正交设计法对提取效果影响较大的提取时间、提取次数、提溶溶剂及体积四个因素进行优化。提取液用Florisil和carb串联固相萃取小柱净化,用HP-5MS柱对这22种农药进行分离,通过GC/MS技术对农药残留进行检测,在0.4 ug/mL和0.1 ug/mL两个水平添加时,平均回收率分别为73.9%～113.7%和67.3%～118.8%,相对标准偏差分别为1.41%～11.29%和3.21%～11.38%,22种农药检测限为0.001～0.01 ug/mL,可以满足茶叶中农药残留限量的检测要求。4.建立了高效液相色谱法测定茶叶中7种氨基甲酸酯农药及其代谢产物的分析新方法。样品经丙酮溶液提取后,再用正已烷-乙醚(1:1,v/v)混合溶剂对提取液进行液-液萃取,然后用活性碳和氟罗里硅土混合固相萃取小柱净化,经高效液相色谱法测定。7种氨基甲酸酯及其代谢产物在0.1～2.0 ug/mL范围内线性良好,相关系数为0.9972～0.9998。在1.0 ug/mL和0.4 ug/mL两个水平添加时,回收率分别为73.2%～98.0%和75.1%～90.4%,相对标准偏差分别为5.59%～9.24%和5.25%～9.73%。该方法简便、快速、灵敏、净化效果,可满足茶叶中氨基甲酸酯类农药及其代谢产物检测要求。更多还原

【Abstract】 Tea is directly soaking dringking food,the quality has closely linked with human’s health.For limiting abuse pesticide and safeguarding the people’s interests,more and more attention has been paid to this issue and many countries have established rigid maximum residue limits(MRLs) for the pesticide in tea.In recent years,there have been quite a few reports concerning the residue analysis of pesticides in tea.However,they are time-consuming,cost a lot of organic solvents, and have a low efficiency in the extraction of residues,In this article,we systematically studied the determination methods of pesticide residues in tea,using chromatography technology,The main results of the study are as follows:1.An efficient and sensitive method for simultaneous determination of eighteen organochlorine and nine pyrethroid pesticides in tea of Jiangxi Province has been established and validated.Pesticide residues were extracted from tea samples with hexane-dichloromethane(1:1,v/v),using Ultrasonic extraction(UE),Extracts were cleaned-up by alumina neutral-florisil column,and determined by gas chromatography equipped with electron-capture detector(GC-ECD),using DB-1701 capillary column.The recoveries of organochlorine pesticides obtained from samples spiked with standards at the concentration levels of 0.04 ug/mLand 0.01 ug/mL were in the ranges of 89.5%～118.2%and 80.0%～112.7%,with the RSD in the ranges of 3.82%～9.64%and 4.26%～11.78%,respectively.The recoveries of pyrethroid pesticides obtained from samples spiked with standards at the concentration levels of 0.20 ug/mL and 0.05 ug/mL were in the ranges of 97.5%～129.6%and 87.3%～110.1%, with the RSD in the ranges of 3.78%～10.72%and 3.02%～13.84%,respectively.The quantification limits of the organochlorine pesticides were in the range of 0.0004～0.001 ug/mL,and the pyrethroids were in the range of 0.0025～0.0050 ug/mL. The satisfactory results were obtained in the determination of organochlorines and pyrethroids in teas of Jiangxi Province.2.A new method for multiresidue analysis of organochlorines and pyrethroids in teas of Jiangxi province is proposed.Pesticide residues were extracted from tea samples with hexane—dichloromethane(1:2,v/v),using microwave-assisted extraction.In this work,the MAE extraction conditions,such as the extraction solvent type,volume,microwave heating time and microwave temperature, optimized by a three level orthogonal array design.Extracts were cleaned-up by alumina neutral-florisil column,and determined by gas chromatography equipped with electron-capture detector(GC-ECD),using DB-1701 capillary column.The recoveries obtained from Chinese tea samples(n=5) spiked with standards at the three concentration levels of 0.4 mL,0.2 mL and 0.1 mL(0.2 ug/mL organochlorines +1.0 ug/mL pyrethroids) were in the ranges of 80.9%～118.5%、88.4%～120.7%and 80.9%～116.3%,with the RSD in the ranges of 1.61%～6.70%、1.89%～6.49%and 1.98%～11.87%,respectively.A satisfactory result was obtained in the determination of pesticides residues in tea of Jiangxi province.3.A new method for multiresidue analysis of 22 organochlorines,pyrethroids, oranophosphorusin and carbamate pesticides in teas is proposed.Pesticide residues were extracted from tea samples with acetonitril-aceton(7:1,v/v).using Ultrasonic extraction(UE),In this work,the UE extraction conditions optimized by a three level orthogonal array design,such as the extraction time,extraction solvent,solvent volume,and the times of extraction.Extracts were cleaned-up by florisil and carb solid phase extraction and determined by gas chromatography equipped with MS detector(GC-MS),using HP-5 capillary column The recoveries obtained from Chinese tea samples(n=5) spiked with standards at the two concentration levels of 0.4 ug/mL and 0.1 ug/mL were in the ranges of 73.9%～113.7%and 67.3%～118.8%, with the RSD in the ranges of 1.41%～11.29%and 3.21%～11.38%,respectively.The quantification limits of the pesticides were in the range of 0.001～0.01ug/mL,A satisfactory result was obtained in the determination of organochlorines,pyrethroids, oranophosphoru and carbamate in teas of Jiangxi province.4.A method for the determination of some carbamate pesticides and their main metabolites using High Performance Liquid Chromatography(HPLC) has been developed.Pesticide residues were extracted from tea samples with acetone,then extracted from acetone with hexane-aether(1:1,v/v),Extracts were cleaned-up by Florisil-Carb solid phase extraction and determined by HPLC with ultraviolet detector.The linearity for NMC standards were good among 0.9972～0.9998,The recoveries of carbamate pesticides obtained from samples spiked with standards at the concentration levels of 1.0 ug/mL and 0.4 ug/mL,were in the ranges of 73.2%～98.0%and 75.1%～90.4%,with the RSD in the ranges of 5.59%～9.24%and 5.25%～9.73%,respectively.These results indicated that this method is simple,rapid, and sensitive for the carbamate pesticides and their main metabolites in Tea of Jiangxi province.更多还原