Abstract:

A method was developed for simultaneous determination of the residues of chlorfenapyr and fipronil in vegetables
using QuEChERS combined with dispersive liquid-liquid microextraction and high performance liquid chromatography.
The sample was extracted with acetonitrile, salted out with MgSO4 and NaCl, cleaned up with N-propyl ethylenediamine
(PSA) and graphitized carbon, and concentrated by dispersive liquid-liquid microextraction (DLLME) before being analyzed
by HPLC. The separation of the target compounds was performed on a SunFire-C18 liquid chromatography column using
a mobile phase consisting of acetonitrile and water in a gradient elution mode and the matrix-matched external standard
calibration method was used for quantitation. Key DLLME experimental parameters including the type and volume
of extractant and disperser solvent and extraction time were optimized. This method had a good linearity in range of
3.0–460 μg/kg with correlation coefficients more than 0.998 6 (R2), and the limits of detectionwere in the range of
0.70–0.86 μg/kg. The average recoveries of chlorfenapyr and fipronil at three spiked concentration levels ranged from 90.5%
to 108.5%, with relative standard deviations (RSDs) less than 10%. This method is simple, accurate, low-cost, and applicable
for the determination of chlorfenapyr and fipronil residues in vegetables.

Key words: chlorfenapyr, fipronil, QuEChERS, dispersive liquid-liquid microextraction, high performance liquid chromatography