Electrochemical sensing of dopamine and pyrogallol on mixed analogue of Prussian blue nanoparticles modified electrodes-Role of transition metal on the electrocatalysis and peroxidase mimetic activity

The electrochemical sensing of dopamine and pyrogallol using mixed copper-iron hexacyanoferrate (Cu-FeHCF) nanodispersion is investigated to understand the dependence of the same on hetero transition-metal ions. We also investigated that Prussian blue and its mixed metal analogues of Mn, Ni and Cu (i.e. Mn-FeHCF, Ni-FeHCF and Cu-FeHCF) possess intrinsic peroxidase like activity capable of catalyzing the oxidation of dopamine (DA) and pyrogallol (Py) by H2O2. The relative variation in catalytic activity based on both electrochemical and spectroscopic measurements of FeHCF, Mn-FeHCF, Ni-FeHCF and Cu-FeHCF nanoparticles is examined for DA sensing and found in the order of: Cu-FeHCF > Mn-FeHCF > Ni-FeHCF > FeHCF. Furthermore, the electrocatalytic activity of Cu-FeHCF towards the DA and Py is also examined based on differential pulse voltammetry. In addition to that, the Cu-FeHCF nanomaterial exhibits excellent electrocatalytic activity with the catalytic rate constant to the order of 1.05 × 102 and 2.34 × 102 M−1 s−1 for DA and Py respectively reflecting the introduction of differential electrocatalytic activity as a function of analytes (DA and Py).