Analysis of phenoxyl-type N-methylcarbamate pesticide residues in vegetables by capillary zone electrophoresis with pre-column hydrolysis and amperometric detection.
With systematic studies of pre-column thermalhydrolysis, a method is described for the determination of fivephenoxyl-type N-methylcarbamates (NMCs) (viz., propoxur, carbofuran, 3-hydroxy-carbofuran, carbaryl, and bendiocarb) in vegetables by capillary zone electrophoresis with amperometric detection. Effects of hydrolysis parameters such as alkali medium, temperature, and hydrolysis time, as well as separation conditions, are investigated. Under the optimum conditions, baseline separation of five hydrolysates is achieved within 16 min. Good calibration curves of propoxur, carbofuran, 3-hydroxy-carbofuran, carbaryl, and bendiocarb are obtained from 1.20x10(-7) to 5.00x10(-5) mol/L, and their detection limits (S/N=3) are 1.80x10(-8), 1.50x10(-8), 1.80x10(-8), 2.50x10(-8), and 1.80x10(-8) mol/L, respectively, which is approximately 20 approximately 50-fold more sensitive than those previously reported with a UV method. In the application of vegetable samples, the five NMCs are well determined. Average recoveries of 75 approximately 89% and 86 approximately 100% at fortified levels of 0.05 and 0.80 mg/kg are achieved with relative standard deviations of 2 approximately 6%, respectively. The method is sensitive, reproducible, and provides an alternative means for the analysis of phenoxyl-type NMC pesticide residues.
Lin
Xucong
X
College of Chemistry and Chemical Engineering, Department of Chemistry, Fuzhou University, Fuzhou 350002, China.
Hong
Qin
Q
Wu
Xiaoping
X
Guo
Liangqia
L
Xie
Zenghong
Z
D004563:Electrochemistry; D019075:Electrophoresis, Capillary / Q000379:methods*; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D010573:Pesticide Residues / Q000032:analysis*; D048448:Phenylcarbamates / Q000032:analysis*; D015203:Reproducibility of Results; D013048:Specimen Handling / Q000379:methods; D014675:Vegetables / Q000737:chemistry*
D010573:Pesticide Residues; D048448:Phenylcarbamates