【作者】 胡贝贞；

【导师】 郭伟强；

【作者基本信息】 浙江大学 ， 分析化学， 2006， 硕士

【摘要】 氨基甲酸酯类农药具有活性广、分解快、高效、选择性强等特点,是当前广泛使用的农药种类之一。随着该类杀虫剂使用量及范围的加大,其在作物中的残留以及对人类健康和环境造成的毒害也越来越为人们所关注,国际上各国先后制定了谷物中多种氨基甲酸酯类农药的最大残留限量,使我国粮谷出口面临越来越多的技术壁垒。因此,建立一种分析粮谷中氨基甲酸酯类农残的简便、快速、高灵敏度的检测方法是迫切而有重要的实践意义。高效液相色谱-串联质谱联用技术是近些年来发展很快的分离分析技术,具有很高的选择性和灵敏度,对复杂基体中的农药残留具有很强的定性能力,准确度高,是目前超痕量农残分析的首选方法。本论文主要研究了粮谷中9种氨基甲酸酯类农药的HPLC-MS/MS测定方法。选用乙腈对粮谷中的氨基甲酸酯进行提取;样品经中性氧化铝固相萃取小柱净化;然后采用HPLC-ESI(+)-MS/MS测定。 氨基甲酸酯类农药的官能团中有羰基,大多数氨基甲酸酯类农药都有苯环,根据“选择性分子间作用力”的基本观点,如果固定相有相似的结构,将使被分离组分与固定相的作用力增强而有利于该类组分的分离。为此,我们选择结构上较为相近的苯磺酰基为特殊官能团,合成了含苯磺酰基的键合固定相,并初步考察了其色谱性能。 第一章,综述了氨基甲酸酯类农药的残留分析研究现状,对各类基体中氨基甲酸酯类农药的提取、净化、测定方法等研究现状进行了详细的介绍和比较。针对液质联用中普遍存在的“基体效应”查阅了相关文献,总结了其来源、产生机理、对分析结果的影响以及补偿的方法。 第二章,研究并建立了粮谷中9种氨基甲酸酯类农药的HPLC-MS/MS分析方法。主要考察了提取溶剂、净化方式对氨基甲酸酯回收率的影响;考察了流动相组成对氨基甲酸酯的分离、质谱响应信号的影响;考察了不同质谱条件对方法灵敏度的影响。实验结果表明,乙腈对9种农药的提取效率最高;中性氧化铝固相萃取小柱能有效除去粗提取物中的大部分杂质;甲醇-乙酸铵溶液(5mmol/L)流动相体系能基本分离各农药,各农药在其中有较好的质谱响应值。 第三章,考察了“基体效应”对分析结果的影响,发现基体效应的存在对分更多还原

【Abstract】 N-methyl carbamates are one kind of the most widely used pesticides nowdays, due to their broad specum of activity, relatively rapid disappearance, effectiveness and selectivity. With the inscreasing use of the pseticides both in amount and in spectrum,more atttention is given to residues in crops and their harms on human health and the environment. Many countries have established the Mamxium Residue Limits of carbamates for grains, making our country faced with more technical barriers of grain export. Therefore, it is urgent and significant to establish a simple, rapid and selective method to determine carbamate rsidues in grains. High Performance Liquid Chromatography-Tandem Mass Spectrometry as an efficient analytical technology, is developing very fast these years. It can achieve excellent selectivity and sentivity. With its powerful qualitative ablity and high accury, it has become the most prefered technology for the ultra-trace analysis of pesticides in complex matrice. The present work majorly focuses on the study of HPLC-MS/MS method for the determination of nine carbamate pesticides in grains. The carbamates were extracted with acetonitrile, cleaned up with alumina-N solid phase extration (SPE) cartridges, and determined by HPLC-ESI(+)-MS/MS.There is carbonyl group in the functional group of carbamates, and most of the carbamates have a phenyl group. Based on the basic viewpoint of "selective intercourse between molecules", if the substance which needs to be separated has a similar structure with the stationary phase, it can be better separated because of its enhanced intercourse with the stationary phase. So, we choose benzenesulfonyl,which has a a similar structure with the carbamates, as a specific functional group and synthesized a stationary phase which contained benzenesulfonyl group. The chromatographic performance of the stationary phase was primarily evaluated.In chapter 1, the research status of carbamate residues analysis was summarized. The extraction, clean-up and determination methods of carbamates in various matrix were presented and evaluated in detail. Based on some literature reviews, acomprehensive summary was made concerning the origins and mechanisms of matrix effects, its consequences and the possible ways of compensating it.In chapter 2, a method for the determiantion of nine carbamate residues in grains by HPLC-MS/MS was studies and established. The influences of extraction solvent and clean-up means on the recoveries of the pesticides were studied;the mobile phase compisition on the seperation and mass spectrometric signal response of the pesticides was examined;the influence of different mass spectrometric conditions on the sensitivy of the method was also studied. The results showed that acetonitrile had the best extraction efficiency on the nine carbamates;alumina-N SPE cartridge could effectively eliminates most of the impurities from the crude extract;the mobile phase composed of methanol-ammonium acetate solution (5mmol/L) could seperate most of the pseticides and the pseticides showed good mass spectrometric signal responses in it.In chapter 3, the consequences of "matrix effects" on the analytical results were evaluated, results showed that the existence of matrix effects had to a high extent an adverse effect on different aspects of the method, such as sensitivity, repeatability, quantification and so on. Different ways of compensating matrix effects were also studied. Results demonstrated that: through modifying mass spectrometric conditions, improving retention and seperation, through a more extensive sample clean-up, matrix effects could be sharply reduced, the employ of matrix-matched calibration in quantification could effectively compensate the effects of matrix components.In chapter 4, a benzenesulfonyl bonded phase was synthesized and characterized with FT-IR and Scan Electron Microscope. Its chromatographic performance was primarily evaluated under mobile phase of methanol-acetic acid solution(pH=4.5). Results showed that the bonded phase had a weaker retention towards polar substances, but its separation ability and stability remained to be improved.更多还原