Selective determination of dopamine by novel electrochemical sensors based on nickelnano particles

Two types of dopamine sensitive and selective electrodes were prepared based on nano nickel modified glassy carbon electrode (nano-Ni-nafion/GCE) and nano nickel modified graphite electrode (nano-Ni-nafion/GE). Nafion film was proven to enhance the selectivity of dopamine (DA) against ascorbic acid (AA). The substrate (i.e., glassy carbon or graphite) was first coated with nafion film. Then electrodepositionof nickel nanoparticles was carried out under anodic conditions and directly from 0.1 M NaOH solutions containing 12 mMgluconate and 12 mM NiSO4using cyclic voltammetry in a potential window between –0.1 and 1.1 V vs. Ag/AgCl.The response of the prepared modified electrodestowardsdopaminewas found to be linear in the concentration range 1-2000 ppm with a detection limit of 1.62 µM (nano-Ni-nafion/GCE) and 0.29µM (nano-Ni-nafion/GE). DA sensors exhibited a sensitivity of 13.8,61.3 mA mol-1Lfor nano-Ni-nafion/GCE and nano-Ni-nafion/GE, respectively. A recovery study of DA using the optimized DA sensors indicated an average recovery of 97.9% (nano-Ni-nafion/GCE) and 99.2% (nano-Ni-nafion/GE).