Detection of dopamine with a modified-graphene oxide nano sheets paste electrode using voltammetry

Dopamine (DA) is considered as one of the key neurotransmitter and plays vital role in our central nervous system [1]. The high concentrations of DA leads to severe disorders likeParkinson’s disease. Hence, the accurate determination of DA in real samples is of great importance to the readers of analytical electrochemistry [2]. After developing the carbon paste electrode (CPE), it has been used as an appropriate bed for electro-oxidation of organicsubstances. CPEs are suitable conductive matrixes for preparing chemically modified electrodes (CMEs). The CMEs has good electrocatalytic activity, sensitivity, and selectivity; it has also a low detection limit compared to traditional carbon paste electrodes [3]. Over recent years, withthe development of nanoscience and nanotechnology, there have been various attempts to applied novel nanomaterials in creating chemically modified electrodes [4]. In the present work, 2-(4-Oxo-3-phenyl-3,4-dihydroquinazolinyl)-N′-phenyl-hydrazinecarbothioamide wassynthesized and used to construct a modified-graphene oxide nano sheets paste electrode. The electro-oxidation of dopamine at the surface of the modified electrode was studied using cyclic voltammetry (CV), chronoamperometry (CHA), and square wave voltammetry (SWV). Underthe optimized conditions, the square wave voltammetric peak current of dopamine increased linearly with dopamine concentration in the ranges of 5.0×10-7 to 4.0×10−4 M and detection limitof 9.5×10-8 M was obtained for dopamine. Finally this modified electrode was used for determination of dopamine in some real samples.

Keywords:

Dopamine , Carbon paste electrode , Graphene oxide nano sheets , Cyclic voltammetry