determination of diazinon in environmental samples using modified multi-walled carbon nanotubes as pipette-tip solid phase extraction sorbent

In this work, a microextraction technique based on pipette tip solid-phase extraction was used for preconcentration and determination of diazinon. carbon nanotube functionalized by zinc sulfide and ethylene glycol was used as sorbent. determination of diazinon was performed using high performance liquid chromatography and uv detection. important parameters that influence the extraction efficiency (i.e. ph, amount of adsorbent, extraction time, salt addition, volumes of sample and eluting solvent and number of aspirating/dispensing cycles for both solvent and sample) were investigated and optimized. results were showed that method was validated over the range of 0.50 - 100.0 μg l^-1. repeatability was satisfactory, bellow 3.78% for 5 replicate measurements of 20 μg l^-1 of diazinon. the limit of detection of this method is 0.03 μg l^-1 with an enrichment factor of 100 and short extraction time of 8.5 min, which confirmed suggested method is a reliable and accurate for extraction and preconcentration of diazinon.