Abstract
The detection of dopamine, an important neurotransmitter in the central nervous system, is relevant because low levels of dopamine can cause brain disorders. Here, a novel electrochemical platform made of a hydrogel–graphene oxide nanocomposite was employed to electrochemically determine simultaneously dopamine (DA) and ascorbic acid (AA). Unlike previous work, where the base electrode is modified, the active material (graphene oxide, GO) was dispersed in the hydrogel matrix, making an active nanocomposite where the electrochemical detection occurs. The GO, hydrogel and nanocomposite synthesis is described. Dynamic Light Scattering, UV-visible and FTIR spectroscopies showed that the synthesized GO nanoparticles present 480 nm of diagonal size and a few sheets in height. Moreover, the polymer swelling, the adsorption capacity and the release kinetic of DA and AA were evaluated. The nanocomposite showed lower swelling capacity, higher DA partition coefficient and faster DA release rate than in the hydrogel. The electrochemical measurement proved that both materials can be employed to determine DA and AA. Additionally, the nanocomposite platform allowed the simultaneous determination of both molecules showing two well separated anodic peaks. This result demonstrates the importance of the incorporation of the nanomaterial inside of the hydrogel and proves that the nanocomposite can be used as a platform in an electrochemical device to determinate DA using an unmodified glassy carbon electrode.
Highlights
Dopamine (DA) is an important neurotransmitter in the central nervous system [1]
The results show that the redox probes are present as dilute solutions and the hydrogel dimensions fulfill the semi-infinite diffusion boundary conditions, the data analysis can be performed using the theoretical framework for electrochemical measurements in liquid solvents in the semi-infinite regime [31,32]
These results demonstrate that the graphene oxide (GO) presence in the composite produce a separation of ascorbic acid (AA) and DA oxidation peaks
Summary
Dopamine (DA) is an important neurotransmitter in the central nervous system [1]. Low levels of DA can cause brain disorders such as schizophrenia and Parkinson’s disease [2]. Using traditional electrodes, the oxidation peaks of these species overlap, making the simultaneous determination impossible [8,9,10,11,12,13] To overcome this problem, various modified electrodes based on graphene have been developed [5,14,15,16], since GO exhibits good conductivity, wide potential window, large electrochemical active surface area, relatively inert electrochemistry, and high electrocatalytic activity [17,18]. The results show that the redox probes are present as dilute solutions and the hydrogel dimensions fulfill the semi-infinite diffusion boundary conditions, the data analysis can be performed using the theoretical framework for electrochemical measurements in liquid solvents in the semi-infinite regime [31,32] This is in contrast with modified electrodes where complex data analysis is required [34], since the diffusion is constrained by the finite thickness of the films. The NanoC advanced composite can be successfully used to preload DA and AA from complex media, to simultaneously determine DA and AA electrochemically, allowing to build portable electronic devices to make an on-field analysis
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
