Determination of dopamine using the indium tin oxide electrode modified with direct electrodeposition of gold–platinum nanoparticles

Gold–platinum (Au–Pt) nanoparticles (NPs) with a ratio of 3:1 solution of chloride salts in the starting electrolyte were deposited on an indium tin oxide (ITO) surface, using a direct electrochemical method, by 40 successive cyclic voltammetry (CV) scans to obtain AuPtNPs/ITO electrode. The deposited nanoparticles were defined by energy dispersive X-ray spectroscopy (EDX) and scanning electron microscopy (SEM) and electrochemical methods. The nanoparticles size of electrodeposited was ~ 30 nm based on SEM results. The efficacy of number of CV scans in the electrodeposition of nanoparticles on the size of electrodeposited nanoparticles was tested. The elemental composition of AuPtNPs/ITO electrode was determined by EDX. Electrochemical studies proved that the electrocatalytic activity of prepared electrode is excellent towards the oxidation of dopamine (DP). The concentration range of DP from 400 nM to 350 μM was linear and limit of detection DP was 20 nM. It was shown that the AuPtNPs/ITO electrode can be used as a sensor with high reproducibility, sensitivity, and long term stability. The selectivity of electrode for determination of DP was verified with investigating the effect of substances by potential interference on the response of electrode. AuPtNPs/ITO electrode was used for the determination of DP in injection and real samples, with acceptable results. Gold–platinum (Au–Pt) alloy nanoparticles were deposited on ITO surface, using a direct electrochemical method to obtain AuPtNPs/ITO electrode and then used for determination of dopamine.