Determination of four kinds of carbamate pesticides by capillary zone electrophoresis with amperometric detection at a polyamide-modified carbon paste electrode.

In this paper, a polyamide-modified carbon paste electrode in capillary zone electrophoresis with amperometric detection (CZE-AD) was firstly applied to the determination of four carbamate pesticides: fenobucarb, isoprocarb, metolcarb and carbaryl. The four carbamates were hydrolyzed in alkalescent aqueous solutions, resulting in the formation of 2-sec-butylphenol, 2-isopropylphenol, m-cresol and alpha-naphthol, which could be determined by amperometry after capillary electrophoretic separation. Under the selected optimum conditions, the four analytes could be perfectly separated within 23min. The linear ranges of 2-sec-butylphenol, 2-isopropylphenol and m-cresol were from 1.0x10(-7) to 2.0x10(-5)molL(-1) and that of alpha-naphthol was from 2.0x10(-7) to 2.0x10(-5)molL(-1) and their detection limits were 3.0x10(-8), 3.0x10(-8), 3.0x10(-8) and 6.0x10(-8)molL(-1), respectively (S/N=3). Fenobucarb, isoprocarb, metolcarb and carbaryl can be indirectly determined by this CZE-AD method with recovery of 105, 104, 110 and 98% and R.S.D. of 4, 3, 4 and 3%, respectively. Above results demonstrated that this method was of high sensitivity, good repeatability and could be used in the rapid determination of the pesticide residues.