Determination of residual pesticide in plant materials using planar cholinesterase sensors modified with Nafion

Amperometric cholinesterase biosensors based on planar screen-printed carbo n electrodes modified with Nafion were developed for determining residual p esticides exhibiting anticholinesterase activity in plant materials. When s tored under dry conditions biosensors retained their normal operation for s ix months. Simplified extraction methods were proposed to eliminate the eff ects of the matrix and organic solvents. The developed procedure provides t he direct determination of down to 0.1 mg/kg pesticides in wheat, barley, s orghum, and rice grains without the removal of organic solvents.