Abstract:

An ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method to detect metamifop residue in rice plant, rise husk, brown rice and rice field water was established, the samples were extracted with acetonitrile, and cleaned up by PSA, separated by ACQUITY UPLC BEH C₁₈ column (50 mm×2.1 mm, 1.7 μm) and gradient eluted with methanol-water, detected with multiple reaction monitoring (MRM) modes with electrospray ionization and then quantified with external standard method. The results showed that a good linear relationship in the range of 0.005-0.05 μg/mL was found of metamifop with rice plant, brown rice, rise husk and rice field water, with the correlation coefficients (r) of 0.998, 0.996, 0.994 and 0.996, respectively. The method was validated at three spike levels (0.005, 0.05 and 0.5 mg/kg), the average recoveries were 85.8%-114.6%, 80.6%-106.4%, 84.2%-95.0% and 92.8%-109.3% in rice plant, rise husk, brown rice and rice field water, with RSD of 2.7%-6.7%, 3.8%-9.2%, 2.9%-4.6% and 5.0%-12.3%, respectively. The limit of quantization (LOQs) was 0.005 mg/kg. This method could meet the determination requirements, and it was simple, quick, accurate and sensitive, could be used to study the residues of metamifop in rice.

Key words: metamifop, UPLC-MS/MS, rice