Sensitive amperometric detection for capillary electrophoresis of phenol carbamates with in-line thermal hydrolysis...

A strategy on amperometric detection for CZE of phenol carbamates as model analytes with a facile in-line thermal hydrolysis was presented, in which a thermal hydrolysis, subsequent CZE separation and final column-end amperometric detection were accomplished in an intact capillary. Key parameters of hydrolysis dynamics of carbamates and electrochemical detection of the hydrolysates were studied, as well as electrophoretic conditions. Under the optimal conditions, the capillary was utilized as chambers for in situ hydrolysis, CZE separation, and electrochemical detection. The successive separation of hydrolysates of five carbamates (propoxur, carbofuran, 3-OH-carbofuran, carbaryl and bendiocarb) were achieved within 17 min. Applied to vegetable samples, the recoveries of carbamates fortified at 0.02 and 0.05 mg/kg were ranging in 88-107.2 and 86.3-107.3%, respectively. The success in the implementation of such a scheme resulted in a simple instrument as compared with those current analytical methods with post-column derivization or pre-column hydrolysis, or online enrichment in chip, respectively. This protocol might possess a potential utility for the sensitive amperometric detection of phenol carbamates.