Deep eutectic solvent-assisted electropolymerization of MXene-based dual-monomer surface molecularly imprinted sensor for selective detection of myricetin.

A novel surface molecularly imprinted electrochemical sensor for myricetin detection was developed. This sensor employs deep eutectic solvent (DES) as a green multifunctional electrolyte to suppress template oxidation, improve solubility, and assist the electropolymerization of a dual-monomer (p-aminobenzoic acid, p-ABA; pyrrole, Py). The sensor with DES as the electrolyte exhibited a 1.3-fold higher response current than the aqueous system, owing to enhanced myricetin solubility and reduced template oxidation. Meanwhile, it was incorporated with a well-dispersed few-layer MXene to construct an optimal sensitized interface. The dual-monomer system is capable of two types of interactions with myricetin: p-ABA forms hydrogen bonds with its hydroxyl group, while Py undergoes π-π stacking with the aromatic a-ring. This synergistic binding generates an imprinted cavity with high specificity. The amount of sorbent, pH, and voltammetric parameters were all optimized during the experiment. Differential pulse voltammetry (DPV) showed that the sensor exhibited acceptable stability, a wide linear detection range of 2.0-160 µmol/L, and a low limit of detection (LOD) of 0.5 µmol/L (signal-to-noise ratio [S/N] = 3), with an imprinting factor of 3.4. The electrochemical investigation of myricetin in real fruit juice samples showed potential for the proposed sensor, which could have applications in food safety.