Separation and determination of basic orange II, acid orange II and auramine O in soybean products based on ionic liquid reverse micelle microextraction and ultra-high-performance liquid chromatography.

A new analytical method was developed for the separation and determination of basic orange II, acid orange II and auramine O in soybean products. The technique was focused on ionic liquid reverse micelle microextraction (IL-RMME) followed by analysis and determination by ultra-high performance liquid chromatography (UHPLC) with photodiode array detector of three chemical dyes. In this method, IL-RMME solution consisting of ionic liquid [Omim]BF6 and surfactant GenapolX-080 was used as extractant. Important parameters affecting IL-RMME efficiency, such as extraction solvent type and volume, sample solution pH, salt effect, centrifugation speed and time were investigated. Under the optimal condition, the linearity of the method was in the range of 0.1-10 ng mLwith correlation coefficient above 0.9994 and the limits of detection below 0.03 ng mL. At the same time, relative standard deviations of the developed procedure for intra- (n = 5) and inter-day (n = 5) precision were in the range of 5.04-8.50%. The results demonstrated that a simple fast environmentally friendly efficient method was successfully applied in the separation and determination of three chemical dyes in soybean products.