N-Doped Reduced Graphene Oxide/Gold Nanoparticles Composite as an Improved Sensing Platform for Simultaneous Detection of Dopamine, Ascorbic Acid, and Uric Acid

Abstract

Gold nanoparticles (AuNPs) were homogeneously electrodeposited on nitrogen-doped reduced graphene oxide (N-rGO) to modify a glassy carbon electrode (GCE/N-rGO-Au) in order to improve the simultaneous detection of dopamine (DA), ascorbic acid (AA), and uric acid (UA). N-rGO was prepared by the hydrothermal treatment of graphene oxide (GO) and urea at 180 °C for 12 h. AuNPs were subsequently electrodeposited onto the surface of GCE/N-rGO using 1 mM HAuCl4 solution. The morphology and chemical composition of the synthesized materials were characterized by field-emission scanning electron microscopy and X-ray photoelectron spectroscopy. The electrochemical performance of the modified electrodes was investigated through cyclic voltammetry and differential pulse voltammetry measurements. Compared to GCE/rGO-Au, GCE/N-rGO-Au exhibited better electrochemical performance towards the simultaneous detection of the three analytes due to the more homogeneous distribution of the metallic nanoparticles as a result of more efficient anchoring on the N-doped areas of the graphene structure. The GCE/N-rGO-Au-based sensor operated in a wide linear range of DA (3–100 µM), AA (550–1500 µM), and UA (20–1000 µM) concentrations with a detection limit of 2.4, 58, and 8.7 µM, respectively, and exhibited satisfactory peak potential separation values of 0.34 V (AA-DA), 0.20 V, (DA-UA) and 0.54 V (AA-UA). Remarkably, GCE/N-rGO-Au showed a very low detection limit of 385 nM towards DA, not being susceptible to interference, and maintained 90% of its initial electrochemical signal after one month, indicating an excellent long-term stability.

Novel Bimetallic Pd–X (X = Ni, Co) Nanoparticles Assembled on N-Doped Reduced Graphene Oxide as an Anode Catalyst for Highly Efficient Direct Sodium Borohydride–Hydrogen Peroxide Fuel Cells

“…Upon comparing the FESEM images of rGO (Figure S2) and N-rGO (Figure a,b), it is obvious that N-rGO possesses a rougher and more wrinkled surface than rGO. Moreover, after nitrogen doping, the rGO nanosheets become thinner, which can be confirmed by the slightly small d -spacing of N-rGO (≈0.34 nm) determined from the XRD analysis in comparison with the ones reported for bare rGO (≈0.37 nm). , These results are in good agreement with those reported in the literature. ,, …”

“…40,41 These results are in good agreement with those reported in the literature. 38,42,43 The FESEM images of Pd−Ni/N-rGO (Figure 1c,d) and Pd−Co/N-rGO (Figure 1e,f) indicate that the binary metal nanoparticles are densely anchored on the surface of N-rGO nanosheets with a size of 11−13 nm; thus, the N-rGO surface becomes rough without any evidence of agglomeration. This is caused by the great number of defects and vacancies in N-rGO.…”

Simultaneous Analysis of Ascorbic Acid, Uric Acid, and Dopamine at Bare Polystyrene Thermoplastic Electrodes

“…From the SEM and CV data shown, we hypothesize that the ability to resolve AA, DA and UA peaks with this simple fabrication process stems from the surface morphology generated during the polishing process. This agrees with the literature where similarly 3D and edge plane‐rich electrode surface morphologies from carbon nanomaterial modifications led to resolution of the three peaks which allowed simultaneous determination [11,14–20] . PS TPEs also show sharper peaks voltammetry peaks for AA, DA and UA (S.1) and unique morphology relative to that of previously published PMMA and PCL TPE work [29,33] .…”

In Situ Synthesis of a Bi2Te3-Nanosheet/Reduced-Graphene-Oxide Nanocomposite for Non-Enzymatic Electrochemical Dopamine Sensing

“…In particular, a variety of nanomaterials, such as metals or metal oxides [11][12][13][14][15], polymers [16][17][18][19], and carbon materials [20,21], have been fabricated to modify bare glassy carbon electrodes (GCEs) and achieve excellent conductivity, sensitivity, and a large surface area.…”