Fabrication of an electrochemical sensor based on magnetic molecularly imprinted polymer for detection of sunset yellow dye.

Sunset Yellow (SY) is a widely used synthetic azo dye in the food, pharmaceutical, and cosmetic industries, but its excessive release poses serious health and environmental risks. In this study, a magnetic molecularly imprinted polymer (MMIP)-based electrochemical sensor was developed for the selective detection of SY using 1-vinylpyridine as the functional monomer. Scanning electron microscopy (SEM) revealed irregular particle morphologies with an average diameter of approximately 69 nm, attributed to surface cavities formed during the imprinting process. Batch sorption experiments confirmed the high specificity of the MMIPs, with a maximum sorption capacity of 80 mg g− 1 under optimal conditions (pH 2, sorbent dosage 2 mg, contact time 18 min). Sorption kinetics followed a pseudo-second-order model, and adsorption behavior was best described by the Langmuir isotherm, indicating monolayer adsorption. Electrochemical measurements demonstrated that the fabricated sensor exhibited high sensitivity, selectivity, and stability for SY detection. The sensor performed optimally at pH 7, an accumulation time of 60 s, and a concentration of 1.5 × 10⁻³ M, with recovery values of 72.9–99.3% in real water and beverage samples, highlighting its practical applicability for environmental and food analysis. The LOD and LOQ values were found to be 5.82 × 10− 5 M and 1.76 × 10− 4 M, respectively. These results confirm the effectiveness of MMIP-based platforms for rapid, accurate, and selective monitoring of synthetic dyes in complex matrices.