Preconcentration of diazinon using multiwalled carbon nanotubes as solid-phase extraction adsorbents

A sensitive and selective column adsorption method is proposed for the preconcentration and determination of diazinon. Diazinon was preconcentrated on multiwalled carbon nanotubes (MWCNTs) as an adsorbent and then determined by high-performance liquid chromatography (HPLC). Several parameters on the recovery of the analyte were investigated. The experimental results showed that it was possible to obtain quantitative analysis when the solution pH was 6 using 200 mL of validation solution containing 2 μg of diazinon and 5 mL of acetonitrile as an eluent. Recovery of diazinon was 95.2 ± 4.2% with a relative standard deviation for seven determinations of 4.9% under optimum conditions. The maximum preconcentration factor was 200 for diazinon when 1000 mL of sample solution volume was used. The linear range of calibration curve was 0.3 to 10,000 ng mL^− 1 with a correlation coefficient of 0.997 and the detection limit (3S/N) was 0.06 ng mL^− 1. The proposed method was successfully applied to the determination of diazinon in tap water with high precision and accuracy.