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Zhang H.,Zhangzhou Normal University | Huang Q.,Zhangzhou Normal University | Huang Y.,Zhangzhou Normal University | Li F.,Zhangzhou Normal University | And 10 more authors.
Electrochimica Acta | Year: 2014

Graphitic carbon nitride nanosheets with a graphite-like structure have strong covalent bonds between carbon and nitride atoms, and nitrogen atoms in the carbon architecture can accelerate the electron transfer and enhance electrical properties effectually. The graphitic carbon nitride nanosheets-graphene oxide composite was synthesized. And the electrochemical performance of the composite was investigated by cyclic voltammetry and differential pulse voltammetry ulteriorly. Due to the synergistic effects of layer-by-layer structures by π-π stacking or charge-transfer interactions, graphitic carbon nitride nanosheets-graphene oxide composite can improved conductivity, electro-catalytic and selective oxidation performance. The proposed graphitic carbon nitride nanosheets-graphene oxide composite modified electrode was employed for simultaneous determination of ascorbic acid, dopamine and uric acid in their mixture solution, it exhibited distinguished sensitivity, wide linear range and low detection limit. Moreover, the modified electrode was applied to detect urine and dopamine injection sample, and then the samples were spiked with certain concentration of three substances with satisfactory recovery results. © 2014 Elsevier Ltd.

Zhang H.,Zhangzhou Normal University | Dai P.,Zhangzhou Products Quality Supervision Institute | Huang L.,Zhangzhou Products Quality Supervision Institute | Huang Y.,Zhangzhou Normal University | And 4 more authors.
Analytical Methods | Year: 2014

A simple and convenient method for the synthesis of nitrogen-doped carbon dots (N-CDs) was reported. Layers of the N-CDs and ferroceneatβ- cyclodextrin (Fcatβ-CD) host-guest complex were deposited on a glassy carbon electrode (GCE) which was used for highly selective and sensitive detection of uric acid (UA). Under the optimal conditions, compared to bare, N-CD and Fcatβ-CD modified electrodes, the Fcatβ-CD/N-CD/GCE had higher catalytic activity toward the oxidation of UA. Differential pulse voltammetry (DPV) was used as the analytical technique for detection of UA, the observed linear range for the determination of the UA concentration was from 5 μM to 120 μM with the detection limit estimated to be 0.08 μM (3S/N). Meanwhile, it was applied to determine uric acid in spiked samples with satisfactory results. © 2014 the Partner Organisations.

Wei C.,Zhangzhou Normal University | Huang Q.,China Institute of Technology | Hu S.,Zhangzhou Normal University | Zhang H.,Zhangzhou Normal University | And 5 more authors.
Electrochimica Acta | Year: 2014

In this work, an excellent electrochemical sensor based on Nafion/multi-walled carbon nanotubes/carbon dots/multi-walled carbon nanotubes (Nafion/MWCNTs/CDs/MWCNTs) for simultaneous determination of hydroquinone (HQ), catechol (CC) and resorcinol (RS) in 0.1 M phosphate buffer solutions (PBS, pH = 7.0) was found. The functioned MWCNTs, which contained amido bond, were combined to CDs via the electrostatic interaction to build the Nafion/MWCNTs/CDs/MWCNTs modified electrode. As we know, MWCNTs have large specific surface area and CDs have electrical conductivity, which were benefited to build the composite modified electrode. The three dihydroxybenzene isomers could well separate from each other at the scan rate of 100 mV s-1 with a potential difference of 119 mV and 419 mV for the oxidation peak potentials of HQ-CC and CC-RS, respectively. Differential pulse voltammetry (DPV) was used for the simultaneous determination of HQ, CC and RS in their ternary mixture. The peak current obtained was linearly dependent on the HQ, CC and RS concentrations in the range of 1.0 to 200.0 μM, 4.0 to 200.0 μM and 3.0 to 400.0 μM and the detection limits for HQ, CC and RS were 0.07 μM, 0.06 μM and 0.15 μM (S/N = 3), respectively. The modified electrode was applied to detect the tap water, well water and river water and the recoveries of tap water, well water and river water samples were 100.3-109.8% for HQ, 96.0-105.8% for CC and 83.4-101.6% for RS, respectively. © 2014 Elsevier Ltd. All rights reserved.

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