The Study Of Capillary Electrophoresis With Ampere Detection To N-methylcarbamates In Vegetables

This paper is consisted of three parts. It mainly studies the analytical techniques for determination of N-Methylcarbamates pesticides in vegetables.In the first part of this thesis, the progress of the determination methods for N-Methylcarbamates pesticides were described. Variety of analytical methods, such as immunity analise (IA), gas chromatography (GC), high-performance liquid chromatography (HPLC) and so on , have been used for the analysis of N-Methylcarbamates. These analytical techniques have been proven to be very reliable for the analysis of N-Methylcarbamates pesticides in foodstuffs. A relatively novel analytical technique that is CE. The prospects for CE in pesticides are very promising because of its high efficiency, snall quantity of samples, and short analysis time.In the second part, a new method for analyzing N-methylcarbamates in vegetables by capillary zone electrophoresis with amperometric detection (CZE-AD) of theirs phenolic metabolites was developed. Through a rapid and simple pre-column hydrolysis reaction, high electroactive hydrolysis metabolities of five N-methylcarbamates (viz. propoxur (PRO), carbofuran (CAF), 3-hydroxy-carbofuran (3-OH), carbaryl (CAR) and bendiocarb (BEN)) were formed quantificationally and adopted for the optimization of separation and determination to monitor their parent compounds. In a borate buffer (50.0 mmol/L, pH = 9.8), excellent separation of all five analytes was gained within 18 min at a carbon disk electrode with a working potential of + 0.85 V (vs. Ag/AgCl) and separation voltage of + 21 kV. Good linear relationships and limit of detections in the order of 38~50 ng/ml was obtained for five analytes. Applied in cabbage, carrot and pepper, CZE-AD can get a excellent analysis of PRO, CAF, 3-OH, CAR and BEN with no noticed interferences of coexisted substances such as pigment, that disturbed analysis in UV detection obviously. The limit of detection (LODs) of NMCs achieved 0.02 mg/kg and lay below the maximum residue levels (MRLs) established by the Europe union (E.U.). It was more sensitive than that of diode-array or ultraviolet detection reported previously about 20~50 times. The recoveries ranged from 54.1 to 91.6 % (cabbages), 53.9 to 100.3 % (carrots), and...