LC-MS/MS analysis of emerging food contaminants: Quantitation and identification of dicyandiamide in milk and other protein-rich foods

This paper describes an analytical workflow for the detection of dicyandiamide and other nitrogen rich compounds in milk and other protein-rich foods. Food samples were extracted using a simple liquid extraction followed by extensive dilution to minimize possible ion suppression effects ionisation. Liquid chromatography (LC) separation used a normal phase gradient on a hydrophilic interaction chromatography (HILIC) column followed by tandem mass spectrometry (MS/MS) detection. Two selective multiple reaction monitoring (MRM) transitions were detected for each target analyte using the ratio of quantifier and qualifier ion for identification. The sensitivity of the LC-MS/MS system allowed the quantitation of dicyandiamide and other nitrogen rich compounds in milk and other protein-rich foods with limits of quantitation down to low μg/kg. Dicyandiamide was quantified in milk with a limit of quantitation of less than 1μg/kg after 200x dilution of the sample extract. Recovery was determined to be 97.3% with a relative standard deviation of 3.66%.?.