Determination of Diazinon and Fenitrothion in Environmental Water and Soil Samples by HPLC

High performance liquid chromatography (HPLC) methods have been developed for the determination of the organophosphorus pesticides, diazinon, and fenitrothion in environmental water and soil samples; a simple and rapid sample preparation procedure using solid‐phase extraction being developed in the case of water samples. In soil samples, the analytical procedure proposed consisted of a 10‐min ultrasonic extraction of the target compounds from a 20 g soil sample with 20 mL of acetonitrile and, after centrifugation, the filtering and concentration of the supernatant in an SC110H Speed Vac Plus concentrator to evaporate solvents. The quantification of diazinon and fenitrothion was performed using UV photodiode detection at 245 and 267 nm, respectively. The average recoveries from spiked water and soil samples at various concentration levels exceeded 86% with relative standard deviations of 1.8–5.1%. It was possible to determine concentrations of these pesticides in the range 0.1–2 ng/g in water and soil samples with a good level of reproducibility and accuracy.