So far, several chromatographic techniques have been used for the determination of various (water-soluble) synthetic colorants in food, including capillary electrophoresis [9] and [10], thin-layer chromatography [11] and [12], high performance liquid chromatography (HPLC) coupled with ultraviolet-visible spectroscopy (UV–vis) [13], diode-array detection (DAD) [14], [15] and [16] and mass spectrometry (MS) [17] and [18]. In order to carry out the colorants’ rough separation from complex matrices and get higher detection sensitivity, some sample pretreatment processes were also applied prior to instrumental analysis. For example, cloud point extraction (CPE) combined with spectrophotometric method was proposed by Pourreza et al. to simultaneously analyze carmoisine and brilliant blue FCF [19]. Ma et al. developed a liquid–liquid extraction method of colorants using dimethylsulfoxide (DMSO) as the extraction solvent prior to HPLC-DAD-MS analysis [20]. Different solid-phase extraction (SPE) cartridges [21] and [22] were also used to achieve sensitive detection of different colorants. Although be successful, most of these sample pretreatment procedures, however, are labor-intensive, time-consuming, and not environmentally friendly because considerable amounts of organic solvents were usually used.