Determination of 8 Synthetic Food Dyes by Solid Phase Extraction and Reversed-Phase High Performance Liquid Chromatography

Purpose: To develop a simple, selective, and sensitive extraction and assay method for the analysis of eight food dyes.
Methods: All sulphonated colors were extracted by an NH2-aminopropyl-modified silica SPE cartridge, and thereafter determined by reverse phase high performance liquid chromatography (RP-HPLC) using a C18 column with gradient elution of ammonium acetate buffer (pH 6.7), methanol, and acetonitrile. The analysis was carried out on a UV detector with two optimized method settings within 17 min.
Results: Certificated standard material (CRM) was used to validate the method, and significant difference was not observed between the results and assigned values. Maximum LOD was 1.154 ppm at 250 nm for Brilliant blue, and 0.873 ppm for carmoisine. Recovery was 94.2 % for Brilliant blue in jelly powder.
Conclusion: This method was successfully applied to determine colorants in various (30) water-soluble foods, including fruit flavored drinks, sugar confectionery, sweets, etc.

Keywords
Synthetic colors; Food; Fruit flavored drinks; Solid phase extraction; RP-HPLC