Optimization of the Separation, Isolation and Recovery of Selected Pesticides in Water Samples by Solid-Phase Extraction and HPLC Photodiode Array Detection

Abstract

An optimized HPLC method for the analysis of selected pesticides (Atrazine, Diuron, Dichloran, Methiocarb, Folpet, Triazophos, Vinclozolin, Tetradifon and Carbophenothion) is developed by applying a solvent elution programme with two steps, isocratic and gradient mode, both in reverse phase (RP). In the isocratic step, the mobile phase is optimized by a grid search procedure over an water-acetonitrile-methanol solvent triangle. Off-line solid-phase extraction (SPE) has been combined with HPLC using a photodiode array detector (DAD) to isolate, recover and quantify the selected pesticides from water samples at ppb levels. The recoveries are higher than 75% in all cases except for atrazine in sea water (50%) and ground water (64%). 1,5–7.7% and most polar pesticide, Atrazine was only recovered between 50% (sea water) to 85% (drinking water) with CV of 8.3 and 5.0% respectively (Table 2).