A method for rapid screening of 182 pesticide residues in foods according to the Hongkong regulation was developed by gas chromatography coupled with quadrupole-time of flight mass spectrometry (GC-Q-TOF/MS). The target analytes were extracted by acetonitrile with 0.1% (v/v) formic acid, then purified by a modified QuEChERS method. The separation was performed on an Agilent HP-5MS column (30 m×0.25 μm×0.25 mm). The compounds were ionized under electron impact ion source. Qualitative and quantitative detection of compounds were completed by searching accurate mass database with full scan mode. Suspected compounds can be confirmed by the spectrum database of the secondary fragment ions. The matrix effects in 10 kinds of typical foods (rice, mushrooms, soybeans, spinaches, tomatoes, broccoli, grapefruits, carrots, lettuces, cucumbers) were evaluated. The results demonstrated that the linear ranges were from 10 to 500 μg/kg with good correlation coefficients (r>0.99). The limits of quantitation were in the range of 10-100 μg/kg (S/N≥10). The average recoveries at three spiked levels were in the range of 66.1%-121.5%, 75.4%-125.8%, 77.2%-128.9% with relative standard deviations (RSDs) of 0.8%-17.6% (n=6). The method is simple, sensitive and robust, as well as having practical application for its low costs.
