University of North Florida
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Contact Info

Stuart Chalk, Ph.D.
Department of Chemistry
University of North Florida
Phone: 1-904-620-1938
Fax: 1-904-620-3535
Email: schalk@unf.edu
Website: @unf

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Shao J. Dong

Abbrev:
Dong, S.J.
Other Names:
Shao Jun Dong, Shaojun Dong
Address:
Laboratory of Electroanalytical Chemistry and National Analysis and Research Center of Electrochemistry and Spectroscopy, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, Jilin, 130022, China
Phone:
+86-431-5682801
Fax:
+86-431-5689711

Citations 10

"Chemiluminescent Determination Of Glucose With A Modified Carbon Paste Electrode"
Microchem. J. 1999 Volume 62, Issue 2 Pages 259-265
Guobao Xu, Jingzhong Zhang and Shaojun Dong

Abstract: A flow injection analysis detection method for glucose is presented which is based on the oxidation of glucose by glucose oxidase followed by chemiluminescent detection of hydrogen peroxide. Both glucose oxidase and hematin, a chemiluminescent reaction catalyst, were bulk-immobilized conveniently by direct mixing with carbon paste, which allows renewal of the electrode surface by simply polishing or cutting to expose a new and fully active surface in the case of fouling. Luminol in reagent solution passed through the flow cell and reacted with hydrogen peroxide produced by the enzyme reactor in the presence of the catalyst to yield light. An applied potential of -0.4 V avoided the electrode fouling effectively. The log-log plot of the emitted light intensity vs glucose concentration was linear over the range of 1-100 mmol L-1 with a correlation coefficient of 0.992. Application of this method to other chemiluminescent and bioluminescent systems is suggested.
Glucose

"Surface Plasmon Resonance Studies On The Electrochemical Doping/dedoping Processes Of Anions On Polyaniline-modified Electrode"
Langmuir 2002 Volume 18, Issue 26 Pages 10305-10310
Xiaofeng Kang, Yongdong Jin, Guangjin Cheng, and Shaojun Dong

Abstract: The combination of in situ surface plasmon resonance (SPR) with electrochemistry was used to investigate the electrochemical doping/dedoping processes of anions on a polyaniline (PAn)-modified electrode. Electrochemical SPR characteristics of the PAn film before and after doping/dedoping were revealed. The redox transformation between the insulating leucoemeraldine, and the conductive emeraldine, corresponding to the doping/dedoping of anion, can lead to very distinct changes in both the resonance minimum angle and the shape of SPR curve. This is ascribed to the swelling/shrinking effect, and the change of the PAn film in the imaginary part of the dielectric constant resulted from the transition of the film conductivity. In situ recording the time evolution of reflectance change at a fixed angle permits the continuous monitoring of the kinetic processes of doping/dedoping anions. The size and the charge of anions, the film thickness, as well as the concentration of anions are shown to strongly influence the rate of ingress/egress of anions. The time differential of SPR kinetic curves can be well applied in the detecting electroinactive anion by flow injection analysis. The approach has higher sensitivity and reproducibility compared with other kinetic measurements, such as those obtained by amperometry.

"Electrooxidation Of Ascorbic Acid At The Bis(4-pyridyl) Disulfide Modified Gold Electrode"
Electroanalysis 1994 Volume 6, Issue 2 Pages 119-123
Yuanwu Xie, Shaojun Dong

Abstract: A Au disc working electrode was modified by dipping the freshly polished electrode into 1 mM bis(4-pyridyl) disulfide for 2 min. The electrode was used for the study of the electro-oxidation of ascorbic acid using a Ag/AgCl (saturated KCl) reference electrode and a Pt wire counter electrode. The oxidation process was pH dependent due to the static interaction between ascorbic acid and the modified electrode surface. At 0.005-2 mM the peak currents show a good linear relationship with the concentrations of ascorbic acid. The modified electrode has greater stability and can be used in FIA.
Ascorbic acid Environmental Electrode Electrode Electrode

"A Novel Alcohol Dehydrogenase Biosensor Based On Solid-state Electrogenerated Chemiluminescence By Assembling Dehydrogenase To Ru(bpy)32+-Au Nanoparticles Aggregates"
Biosens. Bioelectron. 2007 Volume 22, Issue 6 Pages 1097-1100
Lihua Zhang, Zhiai Xu, Xuping Sun and Shaojun Dong

Abstract: Based on electrogenerated chemiluminescence (ECL), a novel method for fabrication of alcohol dehydrogenase (ADH) biosensor by self-assembling ADH to Ru(bpy)32+-AuNPs aggregates (Ru-AuNPs) on indium tin oxide (ITO) electrode surface has been developed. Positively charged Ru(bpy)32+ could be immobilized stably on the electrode surface with negatively charged AuNPs in the form of aggregate via electrostatic interaction. On the other hand, AuNPs are favourable candidates for the immobilization of enzymes because amine groups and cysteine residues in the enzymes are known to bind strongly with AuNPs. Moreover, AuNPs can act as tiny conduction centers to facilitate the transfer of electrons. Such biosensor combined enzymatic selectivity with the sensitivity of ECL detection for quantification of enzyme substrate, and it displayed wide linear range, high sensitivity and good stability.

"Sol-gel Thin-film Immobilized Soybean Peroxidase Biosensor For The Amperometric Determination Of Hydrogen Peroxide In Acid Medium"
Anal. Chem. 1999 Volume 71, Issue 10 Pages 1935-1939
Bingquan Wang, Bin Li, Zhenxin Wang, Guobao Xu, Qun Wang, and Shaojun Dong

Abstract: An acid-stable soybean-peroxidase biosensor was developed by immobilizing the enzyme in a sol-gel thin film. Methylene blue was used as a mediator because of its high electron-transfer efficiency. The sol-gel thin film and enzyme membrane were characterized by FT-IR, and the effects of pH, operating potential, and temperature were explored for optimum anal. performance by using the amperometric method. The H2O2 sensor exhibited a fast response (5 s), high sensitivity (27.5 µA/mM), as well as good thermostability and long-term stability. In addition, the performance of the biosensor was investigated using flow injection analysis (FIA).
Glass

"Electrochemiluminescence Sensor Using Tris(2,2'-bipyridyl)ruthenium(II) Immobilized In Eastman-AQ55D-silica Composite Thin-films"
Anal. Chim. Acta 2003 Volume 480, Issue 2 Pages 285-290
Haiyan Wang, Guobao Xu and Shaojun Dong

Abstract: An electrochemiluminescence (ECL) sensor with good long-term stability and fast response time has been developed. The sensor was based on the immobilization of tris(2,2'-bipyridyl)ruthenium(II) (Ru(bpy)32+) into the Eastman-AQ55D-silica composite thin films on a glassy carbon electrode. The ECL and electrochemistry of Ru(bpy)32+ immobilized in the composite thin films have been investigated, and the modified electrode was used for the ECL detection of oxalate, tripropylamine (TPA) and chlorpromazine (CPZ) in a flow injection analysis system and showed high sensitivity. Because of the strong electrostatic interaction and low hydrophobicity of Eastman-AQ55D, the sensor showed no loss of response over 2 months of dry storage. In use, the electrode showed only a 5% decrease in response over 100 potential cycles. The detection limit was 1 µmol L-1 for oxalate and 0.1 µmol L-1 for both TPA and CPZ (S/N=3), respectively. The linear range extended from 50 µmol L-1 to 5 mmol L-1 for oxalate, from 20 µmol L-1 to 1 mmol L-1 for TPA, and from 1 µmol L-1 to 200 µmol L-1 for CPZ.

"Amperometric Enzyme Electrode For The Determination Of Hydrogen Peroxide Based On Sol-gel/hydrogel Composite Film"
Anal. Chim. Acta 2000 Volume 407, Issue 1-2 Pages 111-118
Bingquan Wang, Jingzhong Zhang, Guangjin Cheng and Shaojun Dong

Abstract: A new type of organic-inorganic composite material was prepared by sol-gel method, and a peroxidase biosensor was fabricated by simply dropping sol-gel-peroxidase mixture onto glassy carbon electrode surface. The sol-gel composite film and enzyme membrane were characterized by Fourier-transform infrared (FT-IR) spectroscopy and EQCM, the electrochemical behavior of the biosensor was studied with potassium hexacyanoferrate(II) as a mediator, and the effects of pH and operating potential were explored for optimum analytical performance by using amperometric method. The response time of the biosensor was about 10 s; the linear range was up to 3.4 mM with a detection limit of 5 x 10^-7 M. The sensor also exhibited high sensitivity (15 µA mM-1) and good long-term stability. In addition, the performance of the biosensor was investigated using flow injection analysis (FIA), and the determination of hydrogen peroxide in real samples was discussed.
Hydrogen peroxide Amperometry Electrode Electrode Apparatus Optimization

"Flow Injection Analysis Of Glucose At An Amperometric Glucose Sensor Based On Electrochemical Codeposition Of Palladium And Glucose Oxidase On A Glassy Carbon Electrode"
Anal. Chim. Acta 1993 Volume 278, Issue 1 Pages 17-23
Qijin Chi and Shaojun Dong*

Abstract: The amperometric glucose sensor is based on the detection of H2O2 produced by the enzymatic oxidation of glucose. The working electrode was prepared by potentiostatic codeposition of glucose oxidase and Pd at a potential of -0.9 V for 15 min onto a polished vitreous C electrode, coated with a thin layer of Nafion and used with a SCE reference and a Pt wire auxiliary electrode. At an operating potential of +0.3 V the calibration graph was rectilinear for 0.1-2.5 mM glucose. The response time and detection limit were 5 s and 50 µM, respectively. When the sensor was used in a flow injection system the optimum pH and flow rate were 7.2 and 0.7 ml/min, respectively. Under these conditions the response to glucose was rectilinear for 0.001-8 mM and the detection limit was 0.1 µM. The sensor did not respond to ascorbic or uric acids.
Glucose Amperometry Electrode Electrode Sensor Apparatus

"Electrochemiluminescence Of Tris(2,2 -bipyridine)ruthenium(II) Immobilized In Poly(p-styrenesulfonate)-silica-Triton X-100 Composite Thin-films"
Analyst 2001 Volume 126, Issue 7 Pages 1095-1099
Haiyan Wang, Guobao Xu and Shaojun Dong

Abstract: The electrochemiluminescence (ECL) of tris(2,2-bipyridine)ruthenium(ii) [Ru(bpy)(3)(2+)] immobilized in poly(p-styrenesulfonate) (PSS)-silica-Triton X-100 composite films was investigated. The cooperative action of PSS, sol-gel and Triton X-100 attached Ru(bpy)(3)(2+) to the electrode strongly, and the presence of Triton X-100 prevented drying fractures of the sol-gel films during gelation and even on repeated wet-dry cycles. The modified electrode was used for the ECL detection of oxalate, tripropylamine (TPA) and NADH in a flow injection analysis (FIA) system with a newly designed flow cell. The detection scheme exhibited good stability, short response time and high sensitivity. Detection limits were 0.1, 0.1 and 0.5 µmol L-1 for oxalate, TPA and NADH, respectively, and the linear concentration range extended from 0.001 to 1 mmol L-1 for the three analytes. Applications of the flow cell in ECL and electrochemical detection, as well as the immobilization of reagents based on the cooperative action, are suggested.

"Self-gelatinizable Graft Copolymer Of Poly(vinyl Alcohol) With 4-vinylpyridine As An Immobilization Matrix For The Construction Of A Tyrosinase-based Amperometric Biosensor"
Analyst 1999 Volume 124, Issue 5 Pages 699-703
Jingzhong Zhang, Bin Li, Guobao Xu, Guangjin Cheng and Shaojun Dong

Abstract: A tyrosinase-based amperometric biosensor using a self-gelatinizable graft copolymer of poly(vinyl alcohol) with 4-vinylpyridine (PVA-g-PVP) as an immobilization matrix was constructed. The 4-vinylpyridine component of PVA-g-PVP enhances the adherence to a glassy carbon electrode surface. The content of 4-vinylpyridine in this immobilization matrix plays a key role in retaining the activity of tyrosinase. A simple, milder method was adopted by simply syringing the copolymer-tyrosinase aqueous solution on to the electrode surface and allowing water to evaporate at 4°C in a refrigerator. Several parameters, including copolymer composition; pH, applied potential and enzyme membrane composition, ware optimized. The enzyme membrane composition can be varied to obtain higher sensitivity or a wider linear detection range. The biosensor was used for the determination of phenol, p-cresol and catechol. The biosensor exhibited excellent reproducibility, stability and sensitive response and can be used in flow injection analysis. The biosensor showed an extended linear range in hydrophilic organic solvents and it can be used in monitoring organic reaction processes. The analytical performance demonstrated this immobilization matrix is suitable for the immobilization of tyrosinase.