A Review on the Simultaneous Electrochemical Determination of Azo Dyes Used as Colorants in Foods and Beverages

Synthetic azo dyes such as sunset yellow, tartrazine, allura red, amaranth, and azorubine have been widely used in foods and beverages as coloring agents. These colorants are frequently preferred in the industry due to their attractive bright colors, low cost, easy availability, and outstanding storage stability against pH and light. In addition to these advantages, synthetic dyes are known to have adverse effects on human health, including carcinogenicity, asthma, allergies, anxiety, and hyperactivity, especially in children. Organizations such as the Joint FAO/WHO Expert Committee on Food Additives (JECFA) and the EU Scientific Committee on Food (SCF) have determined that the acceptable daily intake of these colorants must not exceed 7.5 mg per kg of body weight. Therefore, the quantitative determination of synthetic dyes in foods and beverages is crucial, and their levels must be strictly controlled in foods. Because these azo dyes are electroactive, numerous studies have been conducted recently on their single or simultaneous electrochemical determination, and review articles have generally been published on the determination of single dyes. This review presents recent electrochemical studies on the highly sensitive and selective simultaneous determination of these colorants using voltammetric methods on various modified electrodes. The study discusses the general properties of azo dyes used as colorants; their electrochemical behavior and oxidation/reduction reaction mechanisms; the electrodes used and their modifications; and finally, their simultaneous voltammetric determination.