Simultaneous determination of fifteen herbicides in cucurbitaceous and solanaceous vegetables by gas chromatography with electron caption detector

A gas chromatography-electron caption detector (GC-ECD) method was developed for simultaneous determination of 15 herbcides (primisulfuron, allidochlor, diuron, nitrapyrin, trifluralin, propyzamide, acetochlor, alachlor, metolachlor, metazachlor, pendimethalin, butachlor, pretilachlor, oxadiazon, diflufenican) in cucurbitaceous and solanaceous vegetable samples. The target herbicides were extracted from the test vegetables (tomato, cucumber, pepper, eggplant, courgette, potato, red bean or radish) with ethyl acetate and dichloromethane, purified by Florisil PR solid-phase extraction, separated on a DM-1 capillary column (30 m×0.32 mm, 0.25 μm), determined by GC-ECD, and quantified by the external standard method. Recoveries of the target herbicides at three spiked concentrations (0.002 mg/kg-0.5 mg/kg) in the tested samples ranged from 77% to 113% with RSDs in the range of 3.5%-10.8%. The limits of quantitation (LOQ) for the studied herbicides ranged from 0.001 to 0.1 mg/kg. The proposed method was applied in the determination of the selected herbicides residues in samples collected from the local market. The found levels of the target herbicides in vegetable samples were lower than maximum residue levels (MRL). The method is very simple, fast and highly sensitive. Thus it can be used for the simultaneous determination of the selected herbicides in cucurbitaceous and solanaceous vegetables.