Abstract:

A liquid chromatography coupled with tandem mass spectrometric (LC-MS/MS) method was proposed for the determination of four dipyrone metabolites in milk, i.e., 4-methylaminoantipyrine (MAA), 4-formylaminoantipyrine (FAA), 4- aminoantipyrine (AA), 4-acetylaminoantipyrine (AAA). Samples were extracted with acetonitrile, and the resulting extract was then cleaned up/defatted with acetonitrile-saturated n-hexane and concentrated by rotary evaporation prior to LC-MS/MS with positive electrospray ionization (ESI) in the multiple reaction monitoring (MRM) mode. FAA, AAA and AA were quantified by the external standard method, while MAA by the internal standard method. The limits of detection of FAA, AAA, AA and MAA by the method were 0.24, 0.20, 0.59μg/kg and 0.61μg/kg, respectively. Mean recoveries in blank samples at three spike levels (5, 10, 20μg/kg) ranged between 80.4% and 97.9%, with relative standard deviations less than 9% (n = 10).

Key words: dipyrone, metabolite, milk, LC-MS/MS, determination