HPLC DETERMINATION OF PESTICIDES IN GREEN BEAN SAMPLES AFTER SPE CLEANUP

A reversed-phase high performance liquid chromatographic (HPLC) method with an acetonitrile-methanol-water mobile phase gradient and photodi ode-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 w ith acetone and then partitioned from the vegetable sample with dichlo romethane. Sample cleanup was accomplished by solid-phase extraction ( SPE) using both C-18 and florisil SPE columns. Average recoveries from green beans ranged from 70.0 to 110.1 %. Detection limits of less tha n 0.1 mg kg(-1) were obtained.