Determination of Mesotrionein Food by Liquid Chromatography Tandem Mass Spectrometry

A method for the determination of mesotrione in foods by liquid chromatography tandem mass spectrometry (LC-MS/MS) has been developed. The mesotrione in food samples was extracted with acetonitrile-water (3:1, V/V). The extract was cleaned up by gel permeation chromatography (GPC) and solid phase extraction cartridges (SPE), and then diluted to a certain volume with methanol. The mobile phase in LC was an acetonitrile-0.1% formic acid aqueous solution. Electrospray ionization (ESI) source in negative ionization mode as well as multiple reaction monitoring(MRM) mode was used in the detection. The final solution was determined and confirmed by LC-MS/MS, and quantified by the external standard method. While the fortified levels of mesotrione were in the range of 0.01-0.10 mg/kg, the recoveries were 85.5%-98.1%, and the RSDs were in the range of 3.0%-6.1%. The limit of determination was 0.01 mg/kg. The method is highly sensitive and well repeatable for the determination of mesotrione in foods.