Analytical method development, validation and study on behaviour of ipfencarbazone in paddy (rice)

Supervised field trial was conducted to study persistence of a pre-emergent herbicide, ipfencarbazone (25% SC) on rice crop. Single application of two different doses, 156.25 g a.i.ha^-1/625 mL formulationha^-1 and 312.50 g a.i.ha^-1/1250 mL formulationha^-1, was applied. Method was validated to analyse ipfencarbazone in rice samples (leaf/plant, grain, straw and husk) and in soil. Initial accumulation of ipfencarbazone in rice plants was 6.72 and 14.71 mg kg^-1 in standard and double dose, respectively. The residues decreased linearly with r² values of 0.92 and 0.98 in different doses and reached below limit of quantitation (LOQ) of 0.01 μg kg^-1 (for rice plant/leaf) and 0.05 μg kg^-1 (for rice grain, husk, straw) on 30th and 97th (harvest) day respectively after application in both the doses. An average half-life of ipfencarbazone was approximately 4 days. Less than LOQ levels at harvest and short half-life suggest that the use of ipfencarbazone is safe, provided good agricultural practices (GAP) are followed. The data can be used by regulatory authorities like Food Safety and Standards Authority of India (FSSAI) and CODEX for establishing maximum residue limits (MRLs) of ipfencarbazone.