Simultaneous Detemination Of Acid Orange Dyes And Basic Orange Dyes In Foods By High Performance Liquid Chromatography Tandem Electrospray Mass Spectromethry

Acid orange dyes and basic orange dyes are two kinds of synthetic dyes usually used for silk, wool, fabric dyeing. Due to these colorants are cheaper and steadier than natural food colors, many peddlers add these colors into food illegally. So it is significant for us to build an accurate and sensitive method to detect these dyes. In this study, seven textile dyes including four acid orange dyes (acid orange 6, acid orange 7, acid orange 20 and acid orange 52) and three basic dyes(basic orange 7, basic orange 21, basic orange 22) were separated and detected by high performance liquid chromatography tandem electrospray mass spectrometry.In this study, we mainly studied Liquid chromatography-electrospray-tandem mass spectrometry (LC-ESI-MS) conditions in order to enhance the response of dyes, extracting solution and the content of ammonia water in it, the pH of loading solution, leacheate, the elute solution and the content of ammonia water in it and its volume, the proportion of mobile phase and its pH, elution gradient. Simultaneous separations of the seven dyes were achieved by using a Zorbax Eclipse Plus C18 column (2.1×150 mm i.d.,3.5μm-Micron; Agilent) at 35℃ with the mobile phase of water (The pH was adjusted to 9 by ammonia water, A) and acetonitrile (B) by gradient elution. Good linearity was obtained over the range of 5-500μg/L of the seven dyes and the correlation coefficient is greater than 0.9998, and the relative standard deviations were 2.93%-10.72%. The limits of detection of equipment for each dyes were 0.5-1 μg/L. And the limits of detection of method for each dyes were 0.5-3μg/L. This method has been applied successfully to the determination of soybean products and marinated eggs. The tested results revealed that the recoveries the seven dyes were between 74.13% and 125.60%, and the relative standard deviations (RSDs) were 2.22%-25.37% when the standard levels were 10μg/kg,50μg/kg,100μg/kg. In conclusion, this method can quantify the seven dyes in foods accurately and sensitively.