果蔬中121种农药残留分析质控体系研究

发布时间：2018-10-18 17:18

【摘要】：果蔬在生长和贮存过程中为了防止病虫害及自身疾病,多被喷洒上一定量的农药,虽绝大部分会由于日晒、雨淋而流失,但在产品中仍残留微量农药。农药残留问题使我国果蔬在进出口贸易中频频遭受技术壁垒的限制。因此,建立一种快速筛查果蔬农药残留的检测方法具有重要的现实意义。本研究依据121种农药在气相色谱-质谱中不同的保留时间,分为四组,根据每种农药不同的响应值配制四组混合标准溶液,并为各组农药建立选择离子监测方法,依据保留时间和特征离子丰度比,对农药进行确证,外标法定量。样品前处理采用乙腈提取,使用SPE固相萃取(Sep-Pak Carbon NH2固相萃取柱)净化技术。实验用样品空白基质提取液配制基质混合标准工作溶液,标准曲线的相关系数均高于0.996。农药的添加回收率在60.57%～117.64%之间,其中咪酰胺、吡氟草胺、甲苯氟磺胺、庚烯磷、敌敌畏的添加回收率在60%-70%之间,其他农药的添加回收率均在70%-120%之间,相对标准偏差均小于15%。方法检出限的范围为0.003～0.375mg/kg,有42种农药的检出限低于国标方法GB/T19648-2006。在38mmin完成一组农药的检测,即使用同一升温程序,总共进样4次,就可以完成121种农残的检测,可满足国内及对外出口蔬菜等农产品的农残检测分析。本实验以黄瓜作为实验基质,对比选择离子扫描总离子谱图发现,黄瓜提取液作为基质配制标准物质响应值均高于或等于空白溶剂所配制的标准物质响应值。农药五氟苯、地茂散、六氯苯、α-BHC、五氯硝基苯、γ-BHC、异稻瘟净、乐果、皮蝇磷、乙烯菌核利、毒死蜱、δ-BHC、环氧七氯、α-硫丹、p,p'-DDE、五氯苯受到基质影响较小,基本可以忽略。其他标准物质有明显的基质增强效应。实验提取了黄瓜、白菜、苹果3种基质的基质液,对比3种基质对C组标准物质的基质效应。基质效应的对比显示不同的基质对农药的基质效应是不同的。有些农药在3种基质中的基质效应变化较大。所以,在实验中基质效应不可忽略,实验认为用空白基质溶液配制标准曲线是补偿基质效应的比较好的办法。
[Abstract]:In order to prevent diseases and insect pests and their own diseases, fruits and vegetables are mostly sprayed with certain amount of pesticides during growth and storage. Although most of them will be lost due to sun and rain, there are still traces of pesticides remaining in the products. The problem of pesticide residues frequently restricts the import and export of fruits and vegetables in China. Therefore, it is of great practical significance to establish a rapid screening method for pesticide residues in fruits and vegetables. According to the retention time of 121 pesticides in gas chromatography-mass spectrometry, this study was divided into four groups. According to the different response values of each pesticide, four groups of mixed standard solutions were prepared, and a selective ion monitoring method was established for each group of pesticides. According to retention time and characteristic ion abundance ratio, pesticide was confirmed and quantified by external standard method. The sample was extracted by acetonitrile and purified by SPE solid phase extraction (Sep-Pak Carbon NH2 solid phase extraction column). The correlation coefficient of the standard working solution was higher than 0.996 when the blank matrix extract of the sample was used to prepare the mixed standard working solution. The recoveries of pesticides were between 60.57% and 117.64%, and the recoveries of midamide, Piraclor, toluenesulfonamide, heptene and dichlorvos were between 60% and 70%, the recoveries of other pesticides were between 70% and 120%, and the relative standard deviations were all less than 15%. The detection limit of the method was 0.003 ~ 0.375 mg / kg, and the detection limit of 42 pesticides was lower than that of the national standard method GB/T19648-2006.. When a group of pesticides were tested by 38mmin, even with the same temperature program, a total of 4 samples were injected, which could be used to detect and analyze the agricultural residues of agricultural products such as vegetables and other agricultural products exported at home and abroad. In this experiment, cucumber was used as experimental substrate, and the response values of Cucumber extract as substrate were higher than or equal to those prepared by blank solvent. Pesticides pentafluorobenzene, dimeo powder, hexachlorobenzene, 伪-BHC, pentachloronitrobenzene, 纬-BHC, isorice blast net, dimethoate, dermatophos, ethylenes ribonucleus, chlorpyrifos, 未-BHC, epoxide heptachloro, 伪-endosulfan, pnpn-DDE-, pentachlorobenzene were less affected by matrix and could be neglected. Other reference materials have obvious matrix enhancement effects. The substrates of cucumber, cabbage and apple were extracted and the effects of three substrates on group C reference materials were compared. The contrast of matrix effect shows that the matrix effect of different matrix on pesticide is different. The matrix effects of some pesticides in the three substrates vary greatly. Therefore, the matrix effect can not be ignored in the experiment. It is considered that the standard curve prepared by blank matrix solution is a better way to compensate the matrix effect.
【学位授予单位】：大连海事大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X839.2

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