微萃取技术在茶叶农药残留检测中的应用

发布时间：2018-05-19 02:21

  本文选题：分散固相萃取 + 分散液液微萃取　； 参考：《河北大学》2017年硕士论文

【摘要】：随着人民生活水平的提高和健康意识的增强,有利于身体健康的茶饮品日益受到消费者的喜爱,然而由农药残留引起的茶叶安全问题也逐渐引起人们的关注。近年来,微萃取样品前处理技术受到越来越多分析工作者的青睐,分散液液微萃取(DLLME)技术和固相微萃取(SPME)技术正是在这一环境下应运而生,因其具有简单、快速、成本低和富集倍数高等显著优点,已被广泛应用于各种样品基质中目标分析物的提取。本文围绕两种微萃取技术展开其在茶叶基质农药残留检测中的应用研究。全文共包括3部分,具体内容如下:1.对新型样品前处理技术进行了总结,重点介绍了分散液液微萃取技术的原理、影响因素及其在食品分析中的应用,顶空固相微萃取技术的原理及其在复杂样品基质中的应用,以及农药残留检测技术。最后介绍了本文的研究背景和研究内容。2.将分散固相萃取和分散液液微萃取(d-SPE-DLLME)相结合,并与气相色谱-三重四极杆质谱(GC-MS/MS)联用,建立了快速测定茶叶中7种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)和多壁碳纳米管(MWCNTs)净化,四氯化碳(CCl4)浓缩萃取,用GC-MS/MS分析。采用全发酵红茶基质,对影响萃取的诸因素进行了优化。以乙腈为提取剂进行分散固相萃取,在进行分散液液微萃取时,以200μL CCl4为萃取剂,1 mL乙腈为分散剂,萃取时间1 min。结果表明,7种农药在10~500μg/kg浓度范围内线性关系良好,相关系数r~2在0.9991~0.9999之间,检出限在0.11~3.01μg/kg之间。7种农药在四种茶叶(红茶、绿茶、乌龙茶和黑茶)3个添加水平下平均回收率范围分别为:82.7~111.8%、75.4~113.6%和82.6~107.1%,相对标准偏差(RSD)≤8.6%(n=5)。本方法具有简单、快速、成本低和检出限低的特点。应用所建立的方法对12种市售茶叶样品进行检测,共检出5种拟除虫菊酯类农药残留。3.利用顶空固相微萃取(HS-SPME)与气相色谱-三重四极杆质谱(GC-MS/MS)联用,建立了茶叶中9种酰胺类除草剂农药残留的快速检测方法。对萃取涂层种类、无机盐种类、水用量、盐用量、萃取温度和萃取时间等固相微萃取条件进行了优化。结果表明,9种农药在50~1000μg/kg浓度范围内线性关系良好,相关系数r~2在0.9925~0.9999之间,定量限在1~50μg/kg之间。4种茶叶基质中9种农药在3个添加水平下平均回收率范围分别为:70.3~125.4%、85.2~118.7%和74.6~113.3%,相对标准偏差(RSD)≤17.4%(n=5)。该方法简单、快速、灵敏度高并且重现性好,可满足茶叶基质中9种酰胺类除草剂农药残留检测的要求。
[Abstract]:With the improvement of people's living standard and health consciousness, the tea beverage which is beneficial to the health is becoming more and more popular by consumers. However, the safety of tea caused by pesticide residues has been paid more and more attention. In recent years, the pretreatment technology of microextraction samples is favored by more and more analysts. The dispersed liquid microextraction (DLLME) technology and solid phase microextraction (SPME) technology emerge as the times require in this environment because of its simplicity and rapidity. The advantages of low cost and high enrichment ratio have been widely used in the extraction of target analytes in various sample substrates. In this paper, two microextraction techniques were applied to the determination of pesticide residues in tea matrix. The full text includes 3 parts, the concrete content is as follows: 1. In this paper, the new sample pretreatment technology was summarized, and the principle, influencing factors and application in food analysis, headspace solid phase microextraction technology and its application in complex sample matrix were introduced. And pesticide residue detection technology. Finally, the research background and content of this paper are introduced. A rapid method for the determination of seven pyrethroid pesticide residues in tea was established by combining dispersive solid phase extraction with dispersible liquid microextraction (d-SPE-DLLME) and gas chromatography-quadrupole mass spectrometry (GC-MS / MS). The samples were purified by acetonitrile extraction (N- propyl ethylenediamine) and multiwalled carbon nanotubes (MWCNTs). CCl4) was concentrated and extracted by GC-MS/MS. The factors affecting extraction were optimized by using the whole fermented black tea substrate. Acetonitrile was used as extractant to disperse solid phase extraction, and 200 渭 L CCl4 was used as extractant and 1 mL acetonitrile as dispersant. The extraction time was 1 min. The results showed that the linear range of seven pesticides was 10 渭 g/kg, the correlation coefficient was between 0.9991 and 0.9999, and the detection limit was between 0.11 and 3.01 渭 g/kg in four kinds of tea (black tea and green tea). The average recoveries of Oolong tea and black tea were 1: 82.7% 111.8% and 82.6% and 107.1%, respectively, and the relative standard deviation (RSDs) 鈮，

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