Reduced Graphene Oxide Screen-Printed FTO as Highly Sensitive Electrodes for Simultaneous Determination of Dopamine and Uric Acid

Abstract

A novel electrochemical sensor was fabricated by simply screen printing reduced graphene oxide (rGO) paste on F-doped tin oxide (FTO) (rGO-SP-FTO) followed by sintering at 450 • C in Argon and employed for detecting dopamine (DA) and uric acid (UA) simultaneously. The rGO film was characterized by using Raman spectroscopy, field emission scanning electron microscope (FE-SEM), and Fourier transform infrared spectroscopy (FTIR). The surface sensing features of rGO-SP-FTO were studied with electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). The rGO-SP-FTO electrode exhibited foremost sensitivity in simultaneous detection of DA and UA without any interference from ascorbic acid (AA). The rGO-SP-FTO electrode showed a good linear response in the range of 0.5-50.0 μM and 5.0-300 μM with detection limits (S/N = 3) of 0.07 μM and 0.39 μM for DA and UA, respectively. The interactions between screen printed rGO with FTO electrode and their influence on how rGO-SP-FTO electrode interacted with UA, DA, and AA were analyzed from experimental observations. The rGO-SP-FTO electrode was able to detect DA in dopamine hydrochloride injection (DAI) and UA in urine sample effectively. Moreover, the designed electrochemical sensor exhibited excellent stability and reproducibility.

Porous tal palm carbon nanosheets: preparation, characterization and application for the simultaneous determination of dopamine and uric acid

“…However, the reduction peak was not amplied enough like the oxidation peak due to the low stability of the oxidized form DAQ, which underwent chemical cyclization. 10 The peak separation (DE p À65 mV) was quite consistent with the theoretical value, reecting a reversible redox reaction of DA at the PTPCNs/GCE. In Fig.…”

“…37 The comparatively higher sensitivity of DA towards the PTPCNs/GCE than UA could possibly be due to the more preferable formation of short-range hydrogen bonding by utilizing its two -OH and one -NH 2 group. 10 The pH variation study of both DA and UA from pH 5-9 further validated the existence of negative functionalities on the PTPCNs. At pH 7, UA and AA preferentially bear negative charge and are converted to urate and ascorbate ions, while DA in a medium of pH 7 mostly exists in cationic form.…”

“…36 The graphitic domain of PTPCNs possessed a comparable amount of free electrons, which induced a great number of non-covalent type interactions, namely pi-pi, with electroactive species DA and UA. 10 In addition, the specic nano level thickness of the PTPCNs could have provided an effective and suitable interface between the electrode and solution that minimized the pathway for mass and electron transfer, thus increasing the rate of electron transfer for DA and UA. 37 BET isotherm and pore size distribution curves affirmed the rmly distributed porous framework of the carbon nanosheets, consisting of an interconnected network of meso and macro pores.…”

“…However, bare electrodes oen exhibit poor reproducibility, a surface fouling effect and may ultimately fail to separate individual identities during concurrent detection. 11 Various modiers, such as precious metal nanoparticle-modied carbon materials, 8 reduced graphene oxide, 10 graphene oxide, 11 conducting polymer, 12 carbon nanotube 13 and porous carbon materials, 14,15 have been reported for the modi-cation of conventional electrodes. Among all of the abovestated materials, porous carbon has been most widely utilized as an electrode modier.…”

Electrochemical Activity Determination of Catechol‐O‐methyl Transferase by Selective Dopamine Detection

“…[50] Most FTO based sensor constructions for the dopamine detection apply different modifications, reduced graphene oxide for instance, in order to separate the dopamine signal from interfering substances. [51] Recently we could show that the application of FTO as electrode not only allows the suppression of the oxidation of ascorbic and uric acid, but provides a good discrimination between different dopamine derivatives. [52] With this background the current study investigates the suitability of a FTO electrode for the electrochemical activity determination of the COMT enzyme.…”