Sensitive and selective determination of vanillin in the presence of dopamine and uric acid using low-cost and trouble-free pencil graphite electrode modified with methyl orange

A simple, low-cost, and trouble-free electrochemical sensor has been developed by electropolymerization of methyl orange (MO) on a pencil graphite electrode (PGE) for the selective and sensitive voltammetric investigation of vanillin (VNL). Surface morphology of poly (methyl orange) modified pencil graphite electrode (poly (MO)/PGE) and bare pencil graphite electrode (BPGE) were examined by scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDX) and electron impedance spectroscopy (EIS). The poly (MO)/PGE shows good electrocatalytic activity over BPGE which was assessed by linear sweep voltammetry (LSV), cyclic voltammetry (CV) and differential pulse voltammetry (DPV) in phosphate buffer solution (PBS). Under optimized conditions, the anodic peak current of the analyte was directly proportional to the concentration of the analyte (1.0–26.0 μM) with the limit of detection (LOD) 0.10 μM. Various parameters like heterogeneous rate constant (k0 = 1.13 × 10−9 cm s−1), number of electrons transferred, and surface concentration (Γ = 4.85 × 10-11 mol cm−2) were calculated. The analytical applicability and selectivity of the modified sensor were deliberated by real sample analysis of VNL in presence of dopamine (DA) and uric acid (UA). Thus, a developed electrochemical sensor could be successfully employed for the analysis of VNL present in real samples.