Application of coupled-column liquid chromatography combined with post-column photochemically induced fluorimetry derivatization and fluorescence detection to the determination of pyrethroid insecticides in vegetable samples

摘要

This study reports the first application of coupled-column liquid chromatography-photochemically induced fluorimetry-fluorescence detection (LC-LC-PIF-FD), demonstrating its potential for the quantitative and selective detection of seven pyrethroids in vegetable samples such as cucumber, green bean, tomato and aubergine. An internal surface reversed-phase (ISRP) column coupled to a C-18 column for analyte clean-up and determination were used, respectively. In comparison with a C18 column, the ISRP substantially improved the separation between analytes and interferences from the vegetable matrix. The limits of detection ranged from 0.01 to 0.22 mu g kg(-1) in the vegetable samples (equivalent to 0.01 and 0.13 mu g L-1 in the extract injected), and limits of determination ranged from 0.56 to 8.33 mu g kg(-1) in the vegetable samples (equivalent to 0.34 and 5.00 mu g L-1 in the extract injected). Samples were extracted into dichloromethane to yield mean recoveries at two levels of concentration between 72.8 and 110.0 in all cases. Relative standard deviations were lower than 11.