[Determination of bifenthrin residue in plant-based foods using gas chromatography-mass spectrometry]

A method was established for the determination of bifenthrin residue in 8 plant-based foods using gas chromatography-mass spectrometry (GC-MS). The grain was extracted by acetonitrile and cleaned up with gel permeation chromatography (GPC) combined with a Florisil solid-phase extraction (SPE) cartridge, while the vegetables and fruits were extracted by ethyl acetate and cleaned up only with a Florisil SPE cartridge. Most of the lipids in the extract for the grain were eliminated by GPC, prior to SPE cleanup. The cleaned extract was analyzed by GC-MS with electron impact (EI) source in selective ion monitoring (SIM) mode. The detection limit was 5 microg/kg (S/N = 10). There was a good linearity within the range of 0.005 -0.5 mg/L with the correlation coefficient of 0.999 9. The recoveries were between 74% - 99% with the relative standard derivations of less than 13% at the spiking levels of 0.005, 0.04 and 0.1 mg/kg.