Synthesis of Nanoporous Gold Electrode and Its Application in Electrochemical Sensor

In ammonia solution, binary gold-silver alloy films were directly deposited onto indium tin oxide (ITO) substrate surface by using electrochemical method with chloroauric acid and silver nitrate as precursors. Then high-surface-area nanoporous gold (NPG) film modified electrodes were fabricated by chemical dealloying of the less noble component silver from the surface. The modified electrodes were characterized. The electrode prepared can be successfully functionalized with self-assembled monolayers of L-cysteine, which can be applied to the sensitive and selective determination of Cu(II). Under the optimal conditions and 5 min of absorption time for Cu(II) ions, the cathodic current is linearly proportional to Cu(II) concentration ranged from 0.05 to 4 μM with a detection limit of 0.03 μM. The relative standard deviation is 4.3% for 1 μM Cu(II) solution. The established method was successfully applied for the determination of Cu(II) in water samples of environment.