Analysis of safflower yellow in food by liquid chromatography with photodiode array and electrospray mass spectrometric detection

The aim of the present study was to examine the applicability of liquid chromatography (LC) with photodiode array detection (PAD) and mass spectrometry (MS) for the determination of natural food colorants such as safflower yellow in foods. The main coloring constituents in safflower yellow as investigated by LC/PAD, were safflomin A (SF-A) and safflomin B (SF-B). The development of an accurate, sensitive, and selective analytical method was attempted by using LC/MS with an electrospray ionization interface. in addition, food prepared by solid-phase extraction (SPE) was evaluated. Cartridges with only the reversed-phase mode (C-18, C-8, and OASIS-HLB) and the mixed-phase mode (reversed phase and anion exchange: Bond Elut Certify 2) were examined in terms of recovery. The recoveries of SF-A and -B were above 70% when the mixed-phase mode cartridge was used. Therefore, the mixed-phase mode phase was found to be more suitable for food sample recovery than the other modes. The detection levels of SF-A and -B in foods were very low, and they could not be detected by LC-UV. However, the combination of LC/MS-selected ion monitoring (SIM) and SPE enabled the successful detection of trace amounts of safflower yellow in food samples.