Dispersive liquid-liquid microextraction combined with high-performance liquid chromatography for the enrichment and sensitive determination of Sudan Red pollutants in water samples.

Sudan Red pollutants have gained more attention in recent years. The present study described a simple and sensitive determination method for Sudan Red pollutants with dispersive liquid-liquid microextraction coupled to high-performance liquid chromatography. Chlorobenzene and ethanol were used as the extraction solvent and disperser solvent, respectively. The possible parameters such as the kind of solvents, ionic strength, and sample pH that could affect the enrichment have been optimized. Under the optimal conditions, the pollutants have been well enriched and the linear ranges of Sudan Red I and II were in the range of 0.3-40 μg/L, and the linear ranges of Sudan Red III and IV were in the range of 1.2-160 μg/L. The detection limits were in the range of 0.18-0.46 μg/L, and the precisions were in the range of 3.7-5.9%. All these demonstrated that the proposed method could be a good alternative for the routine analysis of Sudan Red pollutants in water samples.