High-Resolution Voltammetric Determination of Carmoisine, Allura Red, and Brilliant Blue on Their Simultaneous Presence in Food Products

A voltammetric sensor is developed based on a carbon fiber planar electrode modified with a nanocomposite for the simultaneous determination of synthetic food dyes Carmoisine (Car), Allura Red AC (AR), and Brilliant Blue FCF (BB). The nanocomposite includes nickel oxide nanoparticles, synthesized using a strawberry leaf extract; graphene nanoplatelets; and the cationic surfactant cetyltrimethylammonium bromide. The modified electrode exhibits enhanced responses for all three dyes at an improved resolution. Electrochemical oxidation proceeds irreversibly, governed by surface-controlled processes in the cases of Car and BB, and by diffusion-controlled processes in the case of AR. The proposed method enables the simultaneous voltammetric determination of Car, AR, and BB using the developed sensor. The limits of detection for Car, AR, and BB are 0.05, 0.08, and 0.15 µM, respectively. Under the selected conditions for recording differential pulse voltammetry signals, real samples—including soft drinks, syrup, and marshmallows—were successfully analyzed, recovery from 95 to 104%.