DETERMINATION OF THE INSECTICIDE IMIDACLOPRID IN WATER AND SOIL USINGHIGH-PERFORMANCE LIQUID-CHROMATOGRAPHY

We describe an analytical technique for measuring residues of imidaclo prid, a relatively new and highly active insecticide, in water and soi l using high-performance liquid chromatography (HPLC). All analyses we re performed on reversed-phase HPLC with UV detection at 270 nm using a mobile phase of acetonitrile-water (20:80, v/v). Fortified water sam ples were extracted with either solid-phase extraction (SPE) or liquid -liquid extraction methods. A detection limit of 0.5 mu g/l was achiev ed using the SPE method. The imidacloprid residues in soils were extra cted with acetonitrile-water (80:20, v/v), and the extract was then ev aporated using a rotary evaporator. The concentrated extract was redis solved in 1 ml of acetonitrile-water (20:80, v/v) prior to analysis by reversed-phase HPLC. A detection limit of 5 mu g/kg was obtained by t his method which is suitable for analysis of environmental samples. Ac curacy and precision at 10 and 25 mu g/kg soil samples were 85+/-6% an d 82+/-4%, respectively. (C) 1997 Elsevier Science B.V.