Azoxystrobin, buprofezin, dinocap and hexaconazole are widely used in crop protection of mango from flowering to harvest. Residue assessment of these chemicals on mango fruits was done following treatments at the recommended and double doses as per good agricultural practices (GAP). Mango fruit and soil sample preparation was done by QuEChERS, and analysis was done using LC-MS/MS (liquid chromatography mass spectrometry). Using these techniques, the limit of detection (LOD) determined was 1.5 μg kg-1 and limit of quantification (LOQ) was 0.005 mg kg-1 for all analytes. The residue levels on mango initially were 0.265 and 0.55 mg kg-1 for azoxystrobin, 0.63 and 0.974 mg kg-1 for buprofezin, 0.635 and 0.98 mg kg-1 for dinocap and 0.203 and 0.35 mg kg-1 for hexaconazole from standard and double dose treatments, respectively. The dissipation rate of the pesticides on mango fruits was about the same except for azoxystrobin, which dissipated slowly compared with others. The half-life of degradation (DT50) of azoxystrobin was 10.4-12.1 days; buprofezin, 5.8-8.5 days; dinocap, 5.4-6.2 days; and hexaconazole, 4.4-6.1 days. The pre-harvest interval (PHI) based on European Union (EU) MRL (maximum residue limit) requirements were 1 day for azoxystrobin, 15 and 26 days for buprofezin, 27 and 34 days for dinocap, and 19 and 30 days for hexaconazole. The results of this study can be used to produce mango fruits safe for consumption and to meet the regulatory requirements for export of mango fruits from India.
Keywords: Half-life; LC-MS/MS; Mango; Persistence; Pesticides.