Identification and Quantitation of Water-Soluble Synthetic Colors in Foods by Liquid Chromatography/Ultraviolet–Visible Method Development and Validation

A simple and sensitive liquid chromatography method of analysis has been developed and validated for the simultaneous quantitative determination of food colors in a broad range of foods. The method of analysis applies specific extraction solutions to obtain optimal color extraction. The extraction solutions are composed of different proportions of methanol and ammonium acetate, as the ion-pairing agent. Analysis was performed on reverse-phase C18 Poroshell column with ammonium acetate, methanol, acetonitrile, and acetone gradient elution as the mobile phases. Multiple-specific wavelengths were used to monitor color additives in the visible range to provide higher sensitivity and expanded scope needed for a large number of analytes. All 27 color compounds showed good linearity with regression coefficients predominantly above 0.990. The limit of detection and limit of quantitation values ranged from 0.10 to 0.43 and from 0.34 to 1.45 μg/g, respectively. The precision of the method ranged from 1.4 to 15.9%, while recoveries averaged 72% across all food commodities tested. The method of analysis offers convenience and adequate sensitivity for the analysis of a wide variety of food matrices containing a broad range of colors.