动态微波辅助样品前处理技术在农药残留和重金属元素分析中的应用研究

发布时间：2019-06-18 09:00

【摘要】：动态微波辅助样品前处理技术包括动态微波辅助萃取法和动态微波辅助滤取法两部分。在动态微波辅助萃取法中,样品始终由新鲜的萃取剂进行提取,萃取剂能快速将目标物分离出来,提高了传质效率。该方法易于与其它样品前处理技术联用,可同时处理多个样品,提高了样品处理效率,在农药残留分析中应用广泛。在动态微波辅助滤取法中,使用稀酸作为滤取剂,避免了浓酸的使用,应用于重金属元素的分析,具有快速、样品处理条件温和,操作简单和样品通量高的优点。本文基于实验室开发的动态微波辅助萃取装置,首先将动态微波辅助萃取法与其它样品前处理方法联用,对土壤和大米样品中的农药残留进行萃取、净化和富集;之后,将该装置应用到纯棉纺织品中多种重金属元素的滤取中。具体研究内容如下:1.建立了高通量动态微波辅助萃取结合盐析液液萃取方法,用于土壤样品中毒死蜱的分析。采用乙腈水溶液作为萃取剂,得到的萃取液借助盐析试剂使之分为乙腈相和水相,将乙腈相浓缩后用高效液相色谱-质谱进行检测。实验中对多项实验参数进行了优化,优化后的实验条件为:微波功率,375 W;萃取溶剂,50%乙腈水溶液;萃取剂接收体积:12 m L;萃取剂流速:2 m L min-1;盐析试剂:2 g醋酸铵。最后毒死蜱的检测限和定量下限分别为0.17和0.5 ng g-1,回收率在90.0%-100.5%之间,精密度在1.3%-5.7%之间。该方法应用于多种土壤样品中毒死蜱的检测,结果令人满意。相比于传统方法,该方法可同时处理15个样品,操作简单,有机溶剂用量少。2.建立了高通量动态微波辅助萃取结合基质固相分散法,采用高效液相色谱串联质谱仪,对大米中阿维菌素和溴虫腈进行萃取、净化和检测。将微波作用于基质固相分散的洗脱过程,提高了萃取效率,所得萃取液经吹干重溶后即可用于检测。实验中优化了基质固相分散和动态微波辅助萃取的各项参数,优化后的实验条件为:分散吸附剂,碱性氧化铝;分散剂和样品质量比,2:1;萃取剂,乙腈;萃取剂接收体积,7 m L;萃取剂流速,2 m L min-1;微波功率,600 W。在优化的实验条件下,萃取液得到有效净化,阿维菌素和溴虫腈的检出限均为0.8ng g-1,回收率分别在88.6-91.0%和92.1-96.5%之间。该方法使萃取和净化一步完成,且能对15个样品同时处理,操作简单,节省时间。3.建立了多通量动态微波辅助滤取技术结合ICP-OES法,用于纯棉纺织品样品中的Cr,Cd,Cu,Pb和Ni五种重金属元素的滤取和检测。实验中采用稀释的硝酸作为滤取剂,所得滤取液经简单稀释即可用于检测。实验中优化了动态微波辅助滤取条件,优化的实验条件为:微波功率,375 W;滤取剂,稀硝酸(20%,v/v);滤取液接收体积,20 m L;滤取剂流速,1 m L min-1。在优化的条件下,将该方法用于六种纯棉纺织品样品中五种元素的检测,所得结果与标准方法相当,五种重金属元素的滤取率在82.0-98.7%之间。该方法避免了浓酸的使用,无需转移、赶酸和过滤等操作,可同时处理6个样品。
[Abstract]:The dynamic microwave auxiliary sample pretreatment technique includes the dynamic microwave-assisted extraction method and the dynamic microwave-assisted extraction method. In the dynamic microwave-assisted extraction method, the sample is always extracted by fresh extractant, and the extraction agent can quickly separate the target and improve the mass transfer efficiency. The method is easy to be combined with other sample pretreatment techniques, can simultaneously process a plurality of samples, improves the sample processing efficiency, and has wide application in pesticide residue analysis. In the method of dynamic microwave assisted filtration, dilute acid is used as the filter, so that the use of the concentrated acid is avoided, the analysis of the heavy metal element is applied, the method has the advantages of being fast, the sample processing condition is mild, the operation is simple, and the sample flux is high. In this paper, based on the dynamic microwave auxiliary extraction device developed by the laboratory, the dynamic microwave-assisted extraction method is combined with other sample pretreatment methods to extract, purify and enrich the pesticide residues in the soil and the rice sample, and then, The device is applied to the filtering of a plurality of heavy metal elements in the pure cotton textile. The specific content of the study is as follows:1. In this paper, a high-flux dynamic microwave-assisted extraction combined salting-out liquid-liquid extraction method is established, which is used for the analysis of poison and death in soil samples. An acetonitrile aqueous solution is used as an extraction agent, and the obtained extract is divided into an acetonitrile phase and an aqueous phase by means of a salting-out reagent, and the acetonitrile phase is concentrated to be detected by high-performance liquid chromatography-mass spectrometry. The experimental parameters were optimized and the experimental conditions were as follows: microwave power, 375W, extraction solvent,50% acetonitrile water solution, extraction volume of extractant:12 m L, flow rate of extractant:2 m L min-1, salting-out reagent:2 g of acetic acid solution. The detection limit and the lower limit of the final poison were 0.17 and 0.5ng g-1, and the recovery was between 90.0% and 100.5%, and the precision was between 1.3% and 5.7%. The method is applied to the detection of the poison dead point in a plurality of soil samples, and the result is satisfactory. Compared with the traditional method, the method can simultaneously process 15 samples, the operation is simple, and the amount of the organic solvent is less. A high-flux dynamic microwave-assisted extraction combined matrix solid-phase dispersion method was established, and the extraction, purification and detection of abamectin and brimononitrile in rice were carried out by a high-performance liquid chromatography tandem mass spectrometer. The microwave is applied to the elution process of the matrix solid phase dispersion, the extraction efficiency is improved, and the obtained extract can be used for detection after being dissolved by blowing dry weight. The parameters of matrix solid-phase dispersion and dynamic microwave-assisted extraction were optimized in the experiment. The experimental conditions were as follows: dispersing adsorbent, alkaline alumina, dispersing agent and sample mass ratio,2:1, extractant, acetonitrile, receiving volume of extractant,7 m L, flow rate of extractant,2 m L min-1; Under the optimized experimental conditions, the detection limit of the extract was 0.8 ng g-1, and the recovery was between 88.6 and 91.0% and 92.1-96.5%, respectively. In that method, the extraction and purification step is complete, and the 15 sample can be processed at the same time, so that the operation is simple, and the time is saved. The method of multi-flux dynamic microwave assisted filtration and ICP-OES method was established to filter and test the five heavy metal elements of Cr, Cd, Cu, Pb and Ni in the pure cotton textile samples. The diluted nitric acid is used as the filtering agent in the experiment, and the obtained filtrate can be used for detection by simple dilution. The conditions of dynamic microwave assisted filtration were optimized in the experiment. The experimental conditions were as follows: microwave power, 375W, filter, dilute nitric acid (20%, v/ v), fluid receiving volume,20 m L, flow rate of the filter, and 1 m L min-1. Under the optimized condition, the method is used for the detection of five elements in six pure cotton textile samples, and the obtained result is equivalent to that of the standard method, and the leaching rate of the five heavy metal elements is between 82.0 and 98.7%. The method avoids the use of concentrated acid, does not need transfer, acid and filtration, and the like, and can simultaneously process six samples.
【学位授予单位】：吉林大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O652

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