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A Co3O4 nano-octahedron modified fluorine doped tin oxide electrochemical sensor for detection of benzobicyclon
(2018-03-15)
Puangjan, Apinya
;
Chaiyasith, Suwan
Unique Co<inf>3</inf>O<inf>4</inf> nano-octahedrons for modifying electrode were synthesized through simple chemical reaction. This versatile Co<inf>3</inf>O<inf>4</inf> nanostructure possesses the combined advantages of morphological stability and high porosity that can buffer volume change during electrochemical cycles, shorten diffusion path of electron transport, and exhibit remarkable overall electrochemical performance. Samples were characterized by field transmission electron microscopy, transmission electron microscopy, energy dispersive X-ray spectroscopy, X-ray diffractometry, Fourier transform infrared spectroscopy and electrochemical impedance spectroscopy. An electrode modified by this material was used for detection of benzobicyclon. Square wave voltammetry showed that there was a linear relationship between peak current and concentration in the range of 10.00–582.96 μmol L−1 with a detection limit (S/N = 3) of 0.38 μmol L−1. The modified electrode was used for detection of benzobicyclon in brown rice and rice straw samples with satisfactory recovery, reproducibility and stability. Modified electrodes reported in the literature that were prepared by different methods resulted in other kinds of surface morphologies that did not exhibit the same level of performance.
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Application of functionalized multi-walled carbon nanotubes supporting cuprous oxide and silver oxide composite catalyst on copper substrate for simultaneous detection of vitamin B2, vitamin B6 and ascorbic acid
(2017-07-01)
Puangjan, Apinya
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Chaiyasith, Suwan
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Taweeporngitgul, Wipawee
;
Keawtep, Jeerunda
A new electrochemical sensor was fabricated from chemically functionalized multiwall carbon nanotubes and electrochemically deposited cuprous oxide and silver oxide composite over the nanotubes on copper substrate. The structural, functional, morphological, electrical properties and elemental composition of the composite were characterized by X-ray diffractometry, Fourier transform infrared spectroscopy, field transmission electron microscopy, electrochemical impedance spectroscopy and energy dispersive X-ray spectroscopy. The developed sensor exhibited excellent electrochemical catalytic activity toward oxidation of vitamin B<inf>2</inf> (VB<inf>2</inf>), ascorbic acid (AA) and vitamin B<inf>6</inf> (VB<inf>6</inf>). Compared to the performance of simple copper substrate, that of the modified electrode was greatly superior. This can be attributed to its robust structure, excellent conductivity and large surface area. With a simple electrode that relies on linear diffusion at the surface, an electrochemical analytical method may have a selectivity problem, i.e., various species present in the target medium may oxidize or reduce at potentials not very different from each other. The conducting porous layer of our modified electrode alters this diffusion characteristic to one of approximately ‘thin layer’ that facilitates better discrimination between species. In this work, differential pulse voltammetry was used for simultaneous determination of VB<inf>2</inf>, AA and VB<inf>6</inf>. The linear ranges were 0.05–1752.65 μM, 0.05–1628.54 μM and 0.02–1056.12 μM, and the detection limits (S/N = 3) were 0.014 μM, 0.011 μM and 0.008 μM, respectively. In addition to its high performance, this inexpensive sensor is perfectly stable for simultaneous determination of these species in real samples.
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Electrochemical sensor based on PANI/MnO2-Sb2O3 nanocomposite for selective simultaneous voltammetric determination of ascorbic acid and acetylsalicylic acid
(2016-12-01)
Puangjan, Apinya
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Chaiyasith, Suwan
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Wichitpanya, Saniporn
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Daengduang, Sirirat
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Puttota, Silarin
A new electrochemical sensor made from nanocomposite of manganese dioxide (MnO<inf>2</inf>)-antimony trioxide (Sb<inf>2</inf>O<inf>3</inf>) was fabricated on polyaniline (PANI) - patterned fluorine doped tin oxide (FTO) electrode (PANI/MnO<inf>2</inf>-Sb<inf>2</inf>O<inf>3</inf> nanocomposite/FTO) through a simple potentiostatic deposition method. The properties of the nanocomposite were characterized by field emission scanning electron microscopy, X-ray diffraction, electrochemical impedance spectroscopy and other electrochemical techniques. Such nanostructure combines the advantages of PANI (high conductivity and stability) with that of electrocatalytic species (good electrochemical activity). The sensor was applied for simultaneous determination of ascorbic acid (AA) and acetylsalicylic acid (ASA). The linear relationships between their current intensity and concentration were in the range of 6–265.42 nmol L− 1 and 1.2–228.68 nmol L− 1 with detection limit (S/N = 3) of 1.05 nmol L− 1 and 0.20 nmol L− 1, respectively. Experimental results demonstrated that the sensor possesses high selectivity and suffers no interference from competing species. Moreover, it successfully detected AA and ASA in human urine samples with highly satisfactory results.
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Sb/F-codoped SnO2 nanofibers synthesized by electrospinning
(2016-12-01)
Santibenchakul, Somtop
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Chaiyasith, Suwan
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Pecharapa, Wisanu
In this present work, metal and non-metal doping in tin oxide nanofibers was fabricated by electrospinning technique. Sb/F co-doped SnO<inf>2</inf> nanofibers was synthesized by using polyvinylpyrrolidone as polymer precursor and SnCl<inf>4</inf>·5H<inf>2</inf>O, SbCl<inf>3</inf>, NH<inf>4</inf>F as tin, antimony and fluorine source, respectively. The concentration of polyvinylpyrrolidone and stannic chloride dissolved with mixture solvent of Dimethylformamide and absolute Ethanol were fixed at 8 and 10%w/w and used as staring precursors. Electrospinning process was carried out at 10 kV of applied voltage by maintaining tip to collector distance of 10 cm and the feeding speed of mixed precursor was controlled at 0.5 ml/h. The as-spun nanofibers mats were calcined in air at 600°C for 3 hours to obtain the doped-SnO<inf>2</inf> nanofibers. Thermogravimetric and X-ray diffraction results support that the optimized calcined temperature to remove polyvinylpyrrolidone template and oxidize Sn precursor is 600°C. The morphologies of Sb/F co-doped SnO<inf>2</inf> nanofibers appear in rough surface with rearrangement of Sb/F doped SnO<inf>2</inf> porous nanobeads. The average diameter of Sb/F doped SnO<inf>2</inf> nanofibers is 422 nm with the crystallite size about 22 nm. Fourier-transform infrared and energy-dispersive X-ray spectroscopy results indicate states of transformation of starting precusors to the formation of Sb/F doped SnO<inf>2</inf> nanofibers.
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An efficient ZrO2/Co3O4/reduced graphene oxide nanocomposite electrochemical sensor for simultaneous determination of gallic acid, caffeic acid and protocatechuic acid natural antioxidants
(2016-09-01)
Puangjan, Apinya
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Chaiyasith, Suwan
A novel efficient ZrO<inf>2</inf>/Co<inf>3</inf>O<inf>4</inf>/reduced graphene oxide (rGO) nanocomposite catalyst was prepared by a reflux method. Then, the nanocomposite was positively characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), transmission electron microscopy (TEM) and energy dispersive X-ray spectroscopy (EDS). Afterward, the nanocomposite was fabricated into an electrochemical sensor by casting it onto the surface of a fluorine doped tin oxide (FTO) electrode. The ZrO<inf>2</inf>/Co<inf>3</inf>O<inf>4</inf>/rGO nanocomposite/FTO exhibited a synergistic catalytic effect toward oxidation of gallic acid (GA), caffeic acid (CA) and protocatechuic acid (PA) with the oxidation peak currents increasing linearly with concentrations in the range of 6.24-477.68 nmol L-1, 2.48-524.90 nmol L-1 and 5.40-424.96 nmol L-1 and the limits of detection (S/N = 3) of 1.56 nmol L-1 for GA, 0.62 nmol L-1 for CA and 1.35 nmol L-1 for PA. The proposed electrode was then successfully used for simultaneous determination of the three species in fruit juice, rice and tea samples with satisfactory recoveries, showing the feasibility of its use for electrochemical sensing application.
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PVP-assisted Sb-doped SnO2 nanofibers synthesized by electrospinning process
(2016-01-01)
Santibenchakul, Somtop
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Chaiyasith, Suwan
;
Pecharapa, Wisanu
Well-defined Sb-doped tin oxide (ATO) nanofibers were synthesized by electrospinning technique. Polyvinylpyrrolidone (PVP), SnCl<inf>4</inf>·;5H<inf>2</inf>O and SbCl<inf>3</inf> were chosen as suitable precursors for preparing ATO nanofibers. All of precursors were homogeneously dissolved with the mixture solvent of dimethylformamide (DMF) and absolute ethanol. Electrospinning process was carried out at applied voltage of 10 kV and distance between needle tip to aluminium foil collector was fixed at 10 cm. The injection rate of precursor solution was controlled at 0.5 ml/hr. The as-spun nanofibers were calcined at 600°C with heating rate of 5 °C/min in order to remove the PVP template and improve the crystallinity of ATO structure. Effect of Sb doping concentration on their crystal structure was investigated. The morphology and crystal structure of the electrospun fibers were analyzed by scanning electron microscope (SEM) and X-ray diffraction (XRD). In this work, the obtained ATO nanofibers had average range diameter from 150 to 350 nm with rough surface. Sb doping concentration in ATO nanofibers plays a key role on their network morphology. The excellent doping concentration of Sb that offered the continuous fibrous and porous ATO nanofibers was 7%.
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NiO/MWCNTs coated F-doped tin oxide working electrode for hydrogen peroxide detection
(2011-01-01)
Jandai, Boonsong
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Woointranont, Papitchaya
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Chaiyasith, Suwan
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Pecharapa, Wisanu
In this work, NiO/MWCNTs composites were synthesized by heat treatment via two methods. MWCNTs was treated by classical oxidative with acid. The treated MWCNTs was mixed with Nickel acetate in various concentration before calcined at 400°C for 2 h to obtain the NiO/MWCNTs and compared with another method that prepared by chemically depositing nickel hydroxide onto carbon nanotubes under microwave irradiation and thermal annealing process. The modified electrode for the detection of hydrogen peroxide was successfully developed on cross-linking between NiO/MWCNTs nanocomposites and fluorine-doped tin oxide (FTO) using nafion as binder. The physical properties of the composites were investigated by Field Emission Scanning Electron Microscope (FE-SEM) and X-ray Diffractometer (XRD). The SEM results indicated that NiO nanoparticles were well distributed on the surface of MWCNTs. The cyclic voltammetry were used to confirm the successful procedure synthesis of NiO/MWCNTs/FTO and the concentration of hydrogen peroxide was determined by amperometry, by mean of the NiO/MWCNTs/nafion/FTO as working electrode. © 2011 Published by Elsevier Ltd.
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Electrocatalytical of chlorophenoxycarboxylic acids at a protoporphyrin IX cobalt(III) chloride modified glassy carbon electrode
(2005-07-15)
Chaiyasith, Suwan
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Tangkuaram, Tanin
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Chaiyasith, Pachernchai
Protoporphyrin IX cobalt(III) chloride (Co(ProP)Cl) was immobilized on a glassy carbon electrode (GCE) to facilitate the electrocatalytical determination of 2,4-dichlorophenoxycarboxylic acids (2,4-D) and three of its derivatives 2-(2,4-dichlorophenoxy) propionic acid (2,4-DP), 2-(2,4,5-trichlorophenoxy) propionic acid (2,4,5-TP) and 4-(2,4-dichlorophenoxy)butyric acid (2,4-DB) in aqueous solution. Co(ProP)Cl was immobilized by a spontaneous adsorption method. The electrocatalytic reduction peak of 2,4-D and its three derivatives was found at -1.12 V (vs. Ag/AgCl). Employing chronoamperometry, the highest limiting current was found for a modified GCE with 1 mM Co(ProP)Cl in acetonitrile|water (1:3; v/v) containing 0.1 M KCl at -1.15 V. Good linear response of the modified electrode was found in 10-400 μM for 2,4-D, 2,4-DP and 2,4,5-TP; and in 10-300 μM for 2,4-DB. The detection limits were estimated as 0.98, 1.14, 0.89, and 2.77 μM for 2,4-D, 2,4-DP, 2,4,5-TP and 2,4-DB, respectively. The lifetime of the Co(ProP)Cl-GCE was seven times for 2,4-D; eight times for 2,4,5-TP; and six times for 2,4-DP and 2,4-DB. © 2005 Elsevier B.V. All rights reserved.

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