Abstract
The metabolism of acetamiprid, a neonicotinoid insecticide, in rats was investigated by monitoring time-dependent changes in plasma levels of acetamiprid and its metabolites using liquid chromatography quadrupole time-of-flight mass spectrometry (LC-QTOF-MS). Acetamiprid was administrated to rats intravenously at 7.1–21.7 mg/kg for analysis of plasma at 0–96 h. Acetamiprid and its four metabolites could be detected and tentatively identified in rat plasma samples. Plasma levels only estimated from peak areas of acetamiprid decreased, with a half-life of about 4 h, and were completely eliminated by 24 h. N-[(6-Chloro-3-pyridyl) methyl]-N′-cyano-acetamidine was most strongly detected at 4 h and was missing at 48 h. The peak areas of N-[(6-chloropyridin-3-yl) methyl]-acetamide increased over time, reached the maximum at 12–24 h, and the metabolite was then completely eliminated at 72 h. N-Cyano-N′-methylacetamidine and 6-(methylsulfanyl) nicotinic acid showed almost the same behaviors as N-[(6-chloro-3-pyridyl) methyl]-N′-cyano-acetamidine. These findings suggested that LC-QTOF-MS enabled us to tentatively estimate acetamiprid metabolism in rats and that these four metabolites may also be useful biomarkers for acetamiprid exposure in humans.
