A biocompatible nano gold modified palladium sensor for determination of dopamine in biological fluids

A simple, sensitive and efficient palladium based sensor for the determination of dopamine has been developed. A stable layer of physisorbed gold nano particles at the surface of palladium has been used as a catalyst support. The modified sensor was characterized by field emission scanning electron microscopy (FE-SEM) and electrochemical impedance spectroscopy (EIS). The oxidation chemistry of dopamine has been investigated at bare and gold nanoparticle modified palladium sensor using cyclic and square wave voltammetry. The oxidation peak potential of dopamine shifted to lower values and peak current increased significantly, which is attributed to the electrocatalytic properties of nano gold modified palladium sensor. The peak potential of dopamine at pH 7.2 was 190 mV and 162 mV at bare and modified sensor respectively. The peak currents of dopamine were found to increase linearly with increase in the concentration range 5-800 μMfor bare and 0.5-1000 μMfor nano gold modified palladium sensor respectively. The detection limit (3σ/b) and sensitivity were found to be 0.6 μM and 0.003 μA μM^-1 for bare, 0.08 μM and 0.015 μA μM.1 for nano gold modified palladium respectively.