Terminal residue analysis of acephate and methamidofos in rice

Abstract

Residue of acephate and its metabolite methamidophos were studied on rice crop under fi eld condition following three application of the acephate at 10 days interval @ 750 and 1500 g ai/ha. The residues were estimated by UPLC and detection by a triple quadrupole mass spectrometer. The limit of detection was 0.005 μg/g for rice straw, husk grain and soil. The per cent average extraction effi ciency was 85.97, 87.21, 88.17, and 85.96 for acephate and 83.13, 83.93, 85.60, and 82.63 for methamidophos in rice straw, husk, grain and soil, respectively. Residues of acephate and methamidophos at harvest in soil, husk, grain and straw were below detection limit and MRL (maximum residue limit) of 0.05 μg/g.