Abstract:

A gas chromatographic (GC) method was established for the determination of chlorfenapyr residue in cucumbers and apples. The target analyte was extracted from samples with acetonitrile, cleaned up on a Frilisil column, and determined by GC with electron capture detector. The average recoveries of 5 replicates of chlorfenapyr at the spike levels of 0.005, 0.01 and 0.5 μg/g were 115.6%, 86.4% and 82.8% in cucumbers, with the relative standard deviations (RSDs) of 2.6%, 7.6% and 9.2% and 109.2%, 95.9% and 94.6% in apples, with the RSDs of 8.0%, 4.2% and 7.6%, respectively. Field tests gave the equations describing the degradation dynamics of chlorfenapyr residue in cucumbers and apples of y = 0.043e-0.1665x and y = 0.115e-0.0734x, with the half lives of 4.2 d and 9.4 d, respectively. The method has the advantages of high sensitivity, accuracy and precision, thereby providing a good approach for the monitoring of chlorfenapyr residue in vegetables and fruits.

Key words: chlorfenapyr, residue, degradation dynamics, cucumbers, apples