Method for detecting water-soluble anionic synthetic pigment in food

The invention provides a method for detecting a water-soluble anionic synthetic pigment in food. The method comprises the following steps of extracting a sample by using an organic solvent, performing dispersive solid-phase extraction and purification, diluting, determining 92 water-soluble anionic synthetic pigments (comprising 10 groups of 24 isomers) by using high performance liquid chromatography-quadrupole static electron orbitrap mass spectrometry, establishing a correction curve by using a standard solution, and quantifying by using an external standard method. According to the method, the advantage of high resolution of quadrupole static electron orbital ion trap mass spectrometry is utilized, a liquid chromatography separation means is combined, and according to the difference of secondary mass spectrometry of the isomers, qualitative and quantitative determination of 92 water-soluble anionic synthetic pigments containing multiple groups of isomers is realized; and identification of water-soluble syn