HPLC Determination of Omethoate Content in Soil

Testing conditions for the omethoate determination byHPLC were optimized to be: Inertsil QDS-SP (4.6*250 μm) at 25℃, an injection of 20μL methanol/water (V/V=10/90) as mobile phase ata flow rate of 1.0 mL·min^-1, and the wave length of 210 nm for ultraviolet detection. A high recovery rate was achieved by using anextraction column with acetone/acetonitrile (V/V=1/3) as the eluting agent. A linear calibration curve for the omethoate concentrations in the range of 0.1-10μg·mL^-1(R²=0.9992) with a minimal detection limit of 0.1 μg·mL^-1 was established. Acetone and ethyl acetate were used as the solvents in the oscillation extraction. The recovery rate of omethoate in the soil samples ranged from 70% to 120% with a relative deviation of 2.08%-8.08%, which was within the requirements for pesticide residue analysis. It appeared that the newly developed HPLC methodology was appropriate for detecting omethoate residues in soil.