Determination of benzoylurea insecticides in apples by high-performance liquid chromatography

A method for the simultaneous determination of the benzoylurea insecticides diflubenzuron, flufenoxuron, flucycloxuron chlorfluazuron and triflumuron in apples using reversed-phase HPLC is described. The separation of analytes was performed on a Separon SGX C8 column (150 × 3 mm I.D., 5 μm) with methanol-water (55:45, v/v) as the mobile phase. Benzoylurea residues were extracted with acetone and then partitioned into dichloromethane. The final clean-up step was conducted by gel permeation chromatography on Bio- Beads SX-3 using cyclohexane-chloroform (3:2, v/v) as the mobile phase.