Target pesticides and method development

By Zita Sebesvari, Toan Pham Van

Based on interviews with farmers, physicochemical properties (solubility, hydrolysis half-life, octanol-water partition coefficient, soil sorption, soil degradation half-life, GUS leaching potential index) of the substances and their potential to harm humans or aquatic organisms (toxicity - WHO hazard class - and fish acute LC50), twelve target pesticides were selected for monitoring. For the substances which can be separated by gas-chromatography the analytical method development has been completed. Briefly, solid phase extraction, and determination with GC-ECD (gas chromatography with electron capture detector) and GC-MS (gas chromatography with mass spectrometer) is used for the analyses. Fig 1 shows a chromatogram of the pesticides (GC-MS).

Figure 1: Chromatogram of the GC-capable target pesticides. 1-3 Internal and recovery standards, 4 Propanil, 5 Alfa-Endosulfan, 6 Butachlor, 7 Hexaconazol, 8 Profenofos, 9 Buprofezin, 10 Beta-Endosulfan, 11 Endosulfan-Sulfate, 12 Propiconazol 1-2, 13 Cypermethrin 1-4, Difenozonazol 1-2.