HPLC determination of pesticides in green bean samples after SPE clean-up

Summary A reversed-phase high performance liquid chromatographic (HPLC) method with an acetonitrile-methanol-water mobile phase gradient and photodiode-array detection (DAD) is described for simultaneous determination of 21 pesticides, frequently used in agriculture, of different types, namely organophosphorus, organochlorine,N-methylcarbamates, triazines and phenylureas in vegetable samples. The pesticides were extracted with acetone and then partitioned from the vegetable sample with dichloromethane. Sample clean-up was accomplished by solid-phase extraction (SPE) using both C₁₈ and florisil SPE columns. Average recoveries from green beans ranged from 70.0 to 110.1%. Detection limits of less than 0.1 mg kg^–1 were obtained.