Abstract: A UPLC-MS/MS method was developed to determine trichlorphon residues in aquatic products. Trichlorphon residues in samples were extracted into ethyl acetate, defatted on an acidic alumina solid phase extraction column, separated  by UPLC, measured by MS/MS in positive ion multiple reaction monitoring mode, and quantified by external standard method. Over the range of 0.02 to 0.8 ng/mL, an excellent linear relationship (r = 0.9992) between trichlorphon concentration and peak area was observed for the standard working solution of trichlorphon. The average spike recoveries for trichlorphon in blank samples ranged from 89.0 % to 93.8 %, with a RSD between 2.1% and 5.4%. The detection limit for trichlorphon was 1μg/kg. This method proved simple, rapid and accurate.

Key words: UPLC-MS/MS, trichlorfon, aquatic products, residues