Determination of Some Pesticides in Tobacco Leaf by High Performance Liquid Chromatography and Sample Preparation with Matrix Solid Phase Dispersion

Abstract

A new method for the simultaneous determination of some pesticides in tobacco leaf by high performance liquid chromatography (HPLC) and sample preparation with matrix solid phase dispersion (MSPD) was developed. A 1.0 g of sample was placed into an agate mortar and gently blended with 4.0 g graphitized carbon black to obtain a homogeneous mixture. This mixture was introduced into a Teflon cartridge. The pesticides fraction was eluted from the cartridge with methanol and the eluant was evaporated to 0.5 mL. The pesticides (terbutylazine, phosmet, napropamide and folpet) were separated on a ZORBAX stable bound (4.6 mm × 100 mm, 1.8 μm) C₁₈ column with acetonitrile and water (50:50) as the mobile phase and detected with photodiode array detector. This method provides good reproducibility and sensitivity for the quanti-fication of terbutylazine, phosmet, napropamide and folpet. The relative standard derivations of overall intra-day variations were less than 3.8 % and the relative standard derivations of inter-day variations were less than 4.5 %. The standard recoveries (three different concentrations of markers: 0.5, 1.0 and 5.0 μg) were ranged from 88-97 %.