Determination of 23 Dyes in Chili Powder and Paste by High-Performance Liquid Chromatography-Electrospray Ionization Tandem Mass Spectrometry

A sensitive and comprehensive method was developed to determine 23 prohibited dyes in chili powder and paste by high-performance liquid chromatography-electrospray ionization tandem mass spectrometry. Target compounds were simultaneously extracted from chili samples with acetonitrile and purified using freezing-lipid filtration. Chromatographic separation was achieved on a Waters UPLC BEH C18 column (100x 2.1 mm, 1.7 mu m) with gradient elution. Detection and quantification were performed using mass spectrometry in multiple reaction monitoring mode. The method was validated for selectivity, linearity, recovery, precision, and limit of quantification (LOQ), using spiked chili powder and paste samples. The average recoveries of analytes were 58.6-122.1%, with relative standard deviations between 1.0% and 18.9%. The LOQs ranged from 0.2 to 50 mu g/kg. This method was successfully applied to chili powder and paste obtained from local markets. Chrysoidine, Rhodamine B, Orange II, and Sudan I and IV were detected in several samples.