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Deng Y.,Hubei University of Education | Luo K.,South-Central University for Nationalities | Liu G.,Chaozhou Quality and Measurement Supervision and Inspection Institute | Hou X.,Chaozhou Quality and Measurement Supervision and Inspection Institute | And 2 more authors.
International Journal of Electrochemical Science | Year: 2016

Polymerization of L-cysteine was performed on a glassy carbon electrode surface using cyclic voltammetric scanning from -0.2 V to 2.0 V. After being immersed in a gold nanorods solution over one night, a gold nanorod modified poly-L-cysteine film electrode (GNRs/poly-L-cysteine/GCE) was successfully fabricated. The assembling of gold nanorods onto the poly-L-cysteine film electrode was confirmed with scanning electron microscope and electrochemical impedance spectroscopy, respectively. Voltammetric behaviors of butyl hydroxy anisd (BHA) at the GNRs/poly-L-cysteine/GCE were investigated. Compared to the bare GCE, the GNRs/poly-L-cysteine/GCE exhibited significantly enhanced effects on the oxidation peak current of BHA. Square wave voltammetric responses were used for the BHA determination. Under optimized conditions, it was found that the oxidation peak current is linearly related to the BHA concentration in the range of 5.0 × 10-8 ~ 7.0 × 10-6 mol L-1. The detection limit was calculated to be 8.5 × 10-9 mol L-1 (S/N=3). The practical application of the GNRs/poly-L-cysteine/GCE was demonstrated by determining BHA in oil samples. Source


Song X.,Hubei University | Shi Z.,Hubei University | Tan X.,Hubei University | Zhang S.,Hubei University | And 3 more authors.
Sensors and Actuators, B: Chemical | Year: 2014

Exfoliated graphite was facilely prepared through one-step liquid exfoliation of graphite powder in N-methyl-2-pyrrolidone. The resulting exfoliated graphite was redispersed into N,N-dimethylformamide, and then used to modify the surface of glassy carbon electrode (GCE) via solvent evaporation. The electrochemical behaviors of tartrazine were studied, and a sensitive oxidation peak was observed. Interestingly, the oxidation peak current of tartrazine was greatly improved on the surface of exfoliated graphite-modified GCE. The considerable peak current enlargement indicates that the exfoliated graphite exhibits remarkable signal enhancement effects toward tartrazine oxidation. The influences of pH value, amount of exfoliated graphite, accumulation potential and time were examined on the oxidation signal of tartrazine. As a result, a sensitive and rapid electrochemical method was developed for the detection of tartrazine. The linear range was from 5 μg/L to 0.2 mg L-1, and the detection limit was 1.5 μg/L (2.8 nM). This new sensor was used in soft drink samples, and the detected results consisted with the values that obtained by high-performance liquid chromatography. © 2014 Elsevier B.V. Source


Wu C.,Huazhong University of Science and Technology | Cheng Q.,Huazhong University of Science and Technology | Li L.,Chaozhou Quality and Measurement Supervision and Inspection Institute | Chen J.,Chaozhou Quality and Measurement Supervision and Inspection Institute | Wu K.,Huazhong University of Science and Technology
Electrochimica Acta | Year: 2014

Graphene nanosheets (GS) were easily prepared via one-step liquid exfoliation of graphite powder in N-methyl-2-pyrrolidone, and then hybridized with porous Fe2O3 microspheres, as confirmed by the measurements of transmission electron microscopy and X-ray diffraction. Scanning electron microscopy tests indicated that the surface roughness of GS-Fe 2O3 hybrid was larger, and three-dimensional structure was more abundant. Compared with GS and Fe2O3 microspheres, the resulting GS-Fe2O3 hybrid remarkably increased the oxidation signals of bisphenol A (BPA). Moreover, the oxidation signals of BPA on GS-Fe2O3 hybrid surface was further enhanced greatly after addition of hexadecyltrimethylammonium bromide (CTAB). Based on the synergetic signal amplification of GS-Fe2O3 hybrid and CTAB, a novel electroanalytical method with high sensitivity was developed for BPA, and the limit of detection was as low as 2.5 nM. © 2013 Elsevier Ltd. All rights reserved. Source


Qu Y.,South-Central University for Nationalities | Liao N.,South-Central University for Nationalities | Chen J.,Chaozhou Quality and Measurement Supervision and Inspection Institute | Liu G.,Chaozhou Quality and Measurement Supervision and Inspection Institute | And 2 more authors.
Nanoscience and Nanotechnology Letters | Year: 2014

Graphene-poly-L-lysine nanosheets (Gr-PLL) were synthesized and fully characterized. Tyrosinase was immobilized on the Gr-PLL nanosheets modified glassy carbon electrode which was employed as an amperometric biosensor for bisphenol A. The obtained biosensor was characterized with scanning electron microscopy and electrochemical impedance spectroscopy. Experimental conditions on the sensing performance of the as-prepared biosensor were investigated. The biosensor displayed a linear response to bisphenol A over a concentration range which spanned from 0.02 μM to 8.0 μM with a detection limit of 0.01 μM (S/N = 3). The biosensor was successfully applied to determine trace amounts of bisphenol A leaching from plastic drinking bottles. Copyright © 2014 American Scientific Publishers. All rights reserved. Source


Xie X.,Wenzhou University | Sun D.,Wenzhou University | Liu G.,Chaozhou Quality and Measurement Supervision and Inspection Institute | Zeng Q.,Chaozhou Quality and Measurement Supervision and Inspection Institute
Analytical Methods | Year: 2014

A kind of mesoporous silica, SBA-15, was prepared using tetraethoxysilane as the silicon source and pluronic P123 as the template. The resulting SAB-15 was then used to modify the surface of a carbon paste electrode (CPE). The electrochemical behavior of diethylstilbestrol was studied, and a sensitive oxidation peak was observed at 0.39 V in pH 4 acetate buffer. Compared with the unmodified CPE, the SBA-15 modified CPE greatly increased the oxidation peak current of diethylstilbestrol, showing strong signal enhancement effects. The influences of pH value, amount of SBA-15, accumulation potential and accumulation time were examined. As a result, a novel electrochemical method was developed for the detection of diethylstilbestrol. The linear range was from 7.5 to 300 nM, and the detection limit was 2.5 nM after 2 min accumulation. The new method was successfully used to detect diethylstilbestrol in water samples, and recovery was from 94.7% to 102.8%. © The Royal Society of Chemistry 2014. Source

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