Fabrication of NiO nanoparticle onto the surface of a modified screenprinted electrode for simultaneous determination of dopamine and uricacid

Dopamine, has been of interest to neuroscientists and chemists since its discovery in the 1950s. As the most important neurotransmitter in the mammalian central nervous system, the amount ofDA distributed in organs has great influences on human movements and emotions. The abnormal low concentration level of DA can cause Tourette’s syndrome, schizophrenia, Parkinson’s disease, Huntington’s disease, HIV infection and other similar neurological disorders. Therefore, the determination of DA for quality control analysis and for medical control is very important [1,2]. Among various analytical methods, modern electrochemical techniques have attracted considerable interest due to the good simplicity, sensitivity, selectivity, stability and often do not require any pre-treatments or pre-separation [3]. Over recent years, various materials includingpolymer, nanocomposite and metal oxide nanoparticles have been employed for the modification of the electrode surfaces. Due to the unique properties of metal oxide nanoparticles, there is amajor interest in the use of them such as ZnO, Co3O4, NiO and CuO to modify the surface of electrode. Among these nanoparticles, nickel oxide (NiO), a p-type semiconductor with a wide band gap of 3.7 eV in room temperature and a high isoelectric point (IEP) of about 10.7, hasbeen studied intensely because of its high chemical stability, electrocatalysis, electron transfer capability and good biological compatibility [4, 5]. A disposable biosensor for determination of dopamine based on nickel oxide nanoparticles and the graphene nanosheets (GN) modifiedscreen-printed carbon electrode (SPCE) was fabricated. The catalytic activity of the NiONPs/GN-SPCEs was demonstrated by the electrochemical measurements. The electrochemical behaviors of dopamine (DA), and uric acid (UA) were investigated by cyclic voltammetry (CV), differential pulse voltammetry (DPV) and chronoamperometry (CHA). The separation of the oxidation peak potentials for DA–UA was about 145 mV, which allowed simultaneously determining dopamine, and uric acid. The electrochemical studies confirmed that the electrooxidation of dopamine at the modified electrode is a diffusion controlled electrochemical process. The DPV was employed for the determination of dopamine; under optimum conditions, the electrochemical oxidation signal of dopamine increased linearly from 0.1-500 μM. The proposed electrochemical biosensor was sensitive, rapid, disposable with low cost, fewer sample volume and easy preparation, which showed great promise for screendetermination of trace dopamine and uric acid in real samples

Keywords:

Nickel oxide nanoparticles , Graphene nanosheets , Screen-printed carbon electrode , Dopamine , Uric acid