Simultaneous determination of 6 herbicides in vegetables, fruits and cereals by gas chromatography

A QuEChERS-GC method was developed for the simultaneous determination of 6 herbicides including trifluralin, 2, 4-D butylate, acetochlor, alachlor, metolachlor and butachlor in vegetables, fruits and cereals. The analytes were extracted from the vegetables and fruits using acetonitrile and removed water using 5g MgSO4 and salted out using 3g NaCl, and then cleaned up with 175 mg PSA, 25 mg C18, 60 mg GCB and 500 mg MgSO4for 4 minutes. The analytes were extracted from the cereals using acetonitrile and removed water using 5g MgSO4 and salted out using 3g NaCl, and then cleaned up with 250 mg PSA, 200 mg C18and 500 mg MgSO4for3 minutes. The purified sample solution after concentrating was separated by a DB-1701 (30m×0.25 mm, 0.25μm) and detected by GC with ECD detector. The calibration standard curve was established using the standard solution diluted with the blank matrix solution. The results showed the liner ranges of six herbicides were well with correlation coefficient above 0.999. The average recoveries were 84.05% ~104.85% and the relative standard deviations ranged from 2.02%~8.28%. The limits of detection were ranged from 0.002μg/mL to0.03μg/mL and the limit of quantification from 0.002mg/kg to 0.02mg/kg. This method was simple, accurate and sensitive to herbicides in vegetables, fruits and cereals.