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Changqing Sun - One of the best experts on this subject based on the ideXlab platform.
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Amperometric Sensor for Trichloroacetic Acid Based on Myoglobin/Colloidal Gold Nanoparticles Immobilized in Titania Sol–Gel Matrix
Electroanalysis, 2006Co-Authors: Weiwei Yang, Yu Bai, Changqing SunAbstract:A new Amperometric Sensor for the determination of trichloroacetic acid (TCA) was developed based on the immobilization of myoglobin/colloidal gold nanoparticles in titania sol–gel matrix. The Sensor showed a pair of well-defined and nearly reversible cyclic voltammetric peaks for the Mb Fe(III)/Fe(II) with a formal potential (E°′) of −335 mV and a peak-to-peak separation was 61 mV vs. Ag/AgCl (3.0 M KCl) at 100 mV s−1 in 0.1 M pH 7.0 phosphate buffer solutions (PBS). The formal potential of the Mb Fe(III)/Fe(II) couple shifted linearly with the pH with a slope of −51.3 mV/pH, indicating that an electron transfer accompanies single-proton transportation. The Sensor displayed a good electrocatalytic response toward the reduction of TCA and the catalytic mechanism was also discussed. The overpotential for the reduction of TCA was lowered by at least 0.8 V compared with that obtained at bare glassy carbon electrode. The linear range spans the concentration of TCA from 2.0×10−6 to1.2×10−5 M and the detection limit was 1.2×10−7 M. In addition, the stability, repeatability and selectivity of the Sensor were also evaluated.
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a new Amperometric Sensor for the determination of bromate iodate and hydrogen peroxide based on titania sol gel matrix for immobilization of cobalt substituted keggin type cobalttungstate anion by vapor deposition method
Sensors and Actuators B-chemical, 2005Co-Authors: Changqing SunAbstract:Abstract A new Amperometric Sensor was fabricated based on the immobilization of complex of Na 2 H 6 CoW 11 Co(H 2 O)O 39 ·14H 2 O (CoW 11 Co) and poly(4-vinylpyridine) (PVP) in a TiO 2 sol–gel matrix by vapor deposition method. The preparation process simplified the traditional sol–gel process and prevented the cracking of conventional sol–gel derived glasses. The electrochemical behavior of the new Amperometric Sensor was studied in detail by cyclic voltammetry, and three reversible two-electron redox waves were observed in acidic aqueous solution in the potential range of −0.1 to −0.7 V. The Sensor displays good electrocatalytic activity toward the reduction of bromate, iodate and hydrogen peroxide in acidic aqueous solution and the catalytic mechanisms were also discussed. The catalysis of the Sensor towards bromate and iodate was systematically studied by Amperometric method. The method gave a linear range from 2.0 × 10 −5 to 4.4 × 10 −3 M and a detection limit of 5.0 × 10 −6 M for BrO 3 − and 2.0 × 10 −6 to 2.8 × 10 −4 and 8.0 × 10 −7 M for IO 3 − , respectively. In addition, the Sensor has some distinct advantages over the traditional polyoxometalate Sensor, such as simple preparation process, fast response and long-term stability.
Ramasamy Ramaraj - One of the best experts on this subject based on the ideXlab platform.
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gold nanoparticles embedded in silica sol gel matrix as an Amperometric Sensor for hydrogen peroxide
Journal of Electroanalytical Chemistry, 2007Co-Authors: Govindhan Maduraiveeran, Ramasamy RamarajAbstract:Abstract Gold nanoparticles (Aunp) embedded in methyltrimethoxysilane sol–gel (SG) film coated electrode was prepared (GC/SG-Aunp) and characterized. The electrochemical response observed for the GC/SG-Aunp electrode reveals that the dispersed gold nanoparticles in the silicate film are in electrical contact with each other. The potassium ferricyanide redox couple was used as a marker to probe the tunable kinetic barrier of the gold nanoparticles dispersion in the silicate matrix. The GC/SG-Aunp electrode showed good electrocatalytic response for hydrogen peroxide (H2O2) reduction without an enzyme or mediator immobilized in the silicate sol–gel film. Linear relationship was observed for H2O2 reduction in the concentration range from 2.5 to 45 μM at the GC/SG-Aunp electrode at an applied potential of −0.5 V and the detection limit was calculated as 3.15 nM. The GC/SG-Aunp modified electrode is simple to prepare and this electrode shows fast response, good stability and reproducible results and could be applied as an Amperometric Sensor for H2O2.
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Gold nanoparticles embedded in silica sol–gel matrix as an Amperometric Sensor for hydrogen peroxide
Journal of Electroanalytical Chemistry, 2007Co-Authors: Govindhan Maduraiveeran, Ramasamy RamarajAbstract:Abstract Gold nanoparticles (Aunp) embedded in methyltrimethoxysilane sol–gel (SG) film coated electrode was prepared (GC/SG-Aunp) and characterized. The electrochemical response observed for the GC/SG-Aunp electrode reveals that the dispersed gold nanoparticles in the silicate film are in electrical contact with each other. The potassium ferricyanide redox couple was used as a marker to probe the tunable kinetic barrier of the gold nanoparticles dispersion in the silicate matrix. The GC/SG-Aunp electrode showed good electrocatalytic response for hydrogen peroxide (H2O2) reduction without an enzyme or mediator immobilized in the silicate sol–gel film. Linear relationship was observed for H2O2 reduction in the concentration range from 2.5 to 45 μM at the GC/SG-Aunp electrode at an applied potential of −0.5 V and the detection limit was calculated as 3.15 nM. The GC/SG-Aunp modified electrode is simple to prepare and this electrode shows fast response, good stability and reproducible results and could be applied as an Amperometric Sensor for H2O2.
Lauro T. Kubota - One of the best experts on this subject based on the ideXlab platform.
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Manganese phthalocyanine as a biomimetic electrocatalyst for phenols in the development of an Amperometric Sensor
Journal of the Brazilian Chemical Society, 2009Co-Authors: Wilney De Jesus Rodrigues Santos, Maria Del Pilar Taboada Sotomayor, Lauro T. Kubota, Flavio Santos Damos, Sonia Maria C N Tanaka, Aline L. Sousa, Auro Atsushi TanakaAbstract:The construction of an Amperometric Sensor for phenolic compounds using a carbon paste electrode modified with manganese phthalocyanine and histidine is reported. Under optimized conditions, at 0 mV vs Ag/AgCl in 0.1 mol dm-3 phosphate buffer solutions (pH 7.0) containing 250 µmol dm-3 H2O2, a linear response for catechol from 20 up to 130 µmol dm-3 was obtained with a sensitivity of 0.56 (± 0.02) µA dm3 µmol-1 cm-2. The detection limit was 1.1 µmol dm-3 and the response time was 2 s. The Sensor presented stable response during 40 successive determinations. The repeatability, evaluated in terms of relative standard deviation, was 3.6% for n = 5 and [catechol] = 10 µmol dm-3. The Sensor responses for other phenolic compounds were also investigated in details. Finally, the applicability of the Sensor was tested in a pharmaceutical containing dopamine and the results compared favorably with those obtained with the official method.
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Amperometric Sensor for nitrite based on copper tetrasulphonated phthalocyanine immobilized with poly-L-lysine film
Talanta, 2007Co-Authors: Aline L. Sousa, Auro Atsushi Tanaka, Lauro T. Kubota, Flavio Santos Damos, Wilney De Jesus Rodrigues Santos, Rita De Cássia Silva Luz, Sônia M.c.n. TanakaAbstract:In this work, an Amperometric Sensor for nitrite detection based on a glassy carbon electrode modified with copper tetrasulphonated phthalocyanine immobilized by polycationic poly-L-lysine film is presented. The modified electrode showed an excellent catalytic activity toward nitrite oxidation. A linear response range from 0.12 up to 12.20 micromol L(-1) was obtained with a sensitivity of 0.83 microA L micromol(-1). The detection limit for nitrite was 36 nmol L(-1). The repeatability of the proposed Sensor, evaluated in terms of relative standard deviation, was 1% for 10 measurements of 10 micromol L(-1) nitrite solution. Finally, the developed Sensor was applied for nitrite determination in water samples and the results were in agreement to the comparative method. The average recovery for the samples was 101 (+/-4)%.
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Amperometric Sensor for nitrite using a glassy carbon electrode modified with alternating layers of iron iii tetra n methyl 4 pyridyl porphyrin and cobalt ii tetrasulfonated phthalocyanine
Talanta, 2006Co-Authors: Wilney De Jesus Rodrigues Santos, Auro Atsushi Tanaka, Lauro T. Kubota, Flavio Santos Damos, Aline L. Sousa, Rita De Cássia Silva Luz, Sônia M.c.n. TanakaAbstract:The development of a highly sensitive Amperometric Sensor for nitrite using a glassy carbon electrode modified with alternated layers of iron(III) tetra-(N-methyl-4-pyridyl)-porphyrin (FeT4MPyP) and cobalt(II) tetrasulfonated phthalocyanine (CoTSPc) is described. The modified electrode showed an excellent catalytic activity and stability for the nitrite oxidation decreasing the peak potentials about 200mV toward less positive values and presenting much higher peak currents than those obtained on the bare GC electrode. A linear response range of 0.2-8.6mumoll(-1), with a sensitivity of 0.37muAlmumol(-1) and detection limit of 0.04mumoll(-1) were obtained with this Sensor. The repeatability of the proposed Sensor, evaluated in term of relative standard deviation, was verified to be 1.4% for 10 measurements of 0.2mumoll(-1) nitrite solution. Interference caused by common ions has been investigated in simulated mixtures containing high concentration level of interfering ions and the Sensor was found to be tolerant against these ions. The developed Sensor was applied for the nitrite determination in water samples and the results were in agreement with those obtained by a comparative method described in the literature. The average recovery for these samples was 100.1 (+/-0.7)%.
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Determination of glutathione in hemolysed erythrocyte with Amperometric Sensor based on TTF-TCNQ.
Clinica chimica acta; international journal of clinical chemistry, 2006Co-Authors: Percy Calvo-marzal, Karin Y Chumbimuni-torres, Nelci Fenalti Höehr, Lauro T. KubotaAbstract:GSH has a relevant role in human metabolism as an indicator of disease risks. An Amperometric Sensor for glutathione (GSH) determination is described as an alternative method featuring simple construction procedure and short time analysis. The developed Sensor was used to determine glutathione at low potential using a TTF-TCNQ complex. The Sensor exhibits a linear response range from 5 to 340 micromol/l under applied potential of 200 mV vs. SCE. The sensitivity and detection limit were 90.1 microA l/mmol cm(2) and 0.3 micromol/l, respectively. When the Sensor was tested in hemolysed erythrocyte samples for GSH determination, a good correlation in results was observed between the Sensor and the spectrophotometric method. The Sensor showed recovery values between 98% and 102%.
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Determination of glutathione in hemolysed erythrocyte with Amperometric Sensor based on TTF-TCNQ
2006Co-Authors: Percy Calvo-marzal, Karin Y Chumbimuni-torres, Nelci Fenalti Höehr, Lauro T. KubotaAbstract:Abstract Background GSH has a relevant role in human metabolism as an indicator of disease risks. An Amperometric Sensor for glutathione (GSH) determination is described as an alternative method featuring simple construction procedure and short time analysis. Method The developed Sensor was used to determine glutathione at low potential using a TTF–TCNQ complex. Results The Sensor exhibits a linear response range from 5 to 340 μmol/l under applied potential of 200 mV vs. SCE. The sensitivity and detection limit were 90.1 μA l/mmol cm 2 and 0.3 μmol/l, respectively. Conclusion When the Sensor was tested in hemolysed erythrocyte samples for GSH determination, a good correlation in results was observed between the Sensor and the spectrophotometric method. The Sensor showed recovery values between 98% and 102%.
Govindhan Maduraiveeran - One of the best experts on this subject based on the ideXlab platform.
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gold nanoparticles embedded in silica sol gel matrix as an Amperometric Sensor for hydrogen peroxide
Journal of Electroanalytical Chemistry, 2007Co-Authors: Govindhan Maduraiveeran, Ramasamy RamarajAbstract:Abstract Gold nanoparticles (Aunp) embedded in methyltrimethoxysilane sol–gel (SG) film coated electrode was prepared (GC/SG-Aunp) and characterized. The electrochemical response observed for the GC/SG-Aunp electrode reveals that the dispersed gold nanoparticles in the silicate film are in electrical contact with each other. The potassium ferricyanide redox couple was used as a marker to probe the tunable kinetic barrier of the gold nanoparticles dispersion in the silicate matrix. The GC/SG-Aunp electrode showed good electrocatalytic response for hydrogen peroxide (H2O2) reduction without an enzyme or mediator immobilized in the silicate sol–gel film. Linear relationship was observed for H2O2 reduction in the concentration range from 2.5 to 45 μM at the GC/SG-Aunp electrode at an applied potential of −0.5 V and the detection limit was calculated as 3.15 nM. The GC/SG-Aunp modified electrode is simple to prepare and this electrode shows fast response, good stability and reproducible results and could be applied as an Amperometric Sensor for H2O2.
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Gold nanoparticles embedded in silica sol–gel matrix as an Amperometric Sensor for hydrogen peroxide
Journal of Electroanalytical Chemistry, 2007Co-Authors: Govindhan Maduraiveeran, Ramasamy RamarajAbstract:Abstract Gold nanoparticles (Aunp) embedded in methyltrimethoxysilane sol–gel (SG) film coated electrode was prepared (GC/SG-Aunp) and characterized. The electrochemical response observed for the GC/SG-Aunp electrode reveals that the dispersed gold nanoparticles in the silicate film are in electrical contact with each other. The potassium ferricyanide redox couple was used as a marker to probe the tunable kinetic barrier of the gold nanoparticles dispersion in the silicate matrix. The GC/SG-Aunp electrode showed good electrocatalytic response for hydrogen peroxide (H2O2) reduction without an enzyme or mediator immobilized in the silicate sol–gel film. Linear relationship was observed for H2O2 reduction in the concentration range from 2.5 to 45 μM at the GC/SG-Aunp electrode at an applied potential of −0.5 V and the detection limit was calculated as 3.15 nM. The GC/SG-Aunp modified electrode is simple to prepare and this electrode shows fast response, good stability and reproducible results and could be applied as an Amperometric Sensor for H2O2.
Bingjoe Hwang - One of the best experts on this subject based on the ideXlab platform.
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bimetallic ptm m pd ir nanoparticle decorated multi walled carbon nanotube enzyme free mediator less Amperometric Sensor for h2o2
Biosensors and Bioelectronics, 2012Co-Authors: Kuanjung Chen, John Rick, Shihhan Wang, Chandrasekara K Pillai, Bingjoe HwangAbstract:Abstract A new highly catalytic and intensely sensitive Amperometric Sensor based on PtM (where M = Pd, Ir) bimetallic nanoparticles (NPs) for the rapid and accurate estimation of hydrogen peroxide (H 2 O 2 ) by electrooxidation in physiological conditions is reported. PtPd and PtIr NPs-decorated multiwalled carbon nanotube nanocatalysts (PtM/MWCNTs) were prepared by a modified Watanabe method, and were characterized by XRD, TEM, ICP, and XAS. The Sensors were constructed by immobilizing PtM/MWCNTs nanocatalysts in a Nafion film on a glassy carbon electrode. Both PtPd/MWCNTs and PtIr/MWCNTs assemblies catalyzed the electrochemical oxidation of H 2 O 2 . Cyclic voltammetry characterization measurements revealed that both the PtM (M = Pd, Ir)/MWCNTs/GCE possessed similar electrochemical surface areas (∼0.55 cm 2 ), and electron transfer rate constants (∼1.23 × 10 −3 cm s −1 ); however, the PtPd Sensor showed a better performance in H 2 O 2 sensing than did the PtIr counterpart. Explanations were sought from XAS measurements to explain the reasons for differences in Sensor activity. When applied to the electrochemical detection of H 2 O 2 , the PtPd/MWCNTs/GC electrode exhibited a low detection limit of 1.2 μM with a wide linear range of 2.5–125 μM ( R 2 = 0.9996). A low working potential (0 V (SCE)), fast Amperometric response ( −1 cm −2 ) were achieved at the PtPd/MWCNTs/GC electrode. In addition, the PtPd/MWCNTs nanocatalyst Sensor electrode also exhibited excellent reproducibility and stability. Along with these attractive features, the Sensor electrode also displayed very high specificity to H 2 O 2 with complete elimination of interference from UA, AA, AAP and glucose.
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bimetallic ptm m pd ir nanoparticle decorated multi walled carbon nanotube enzyme free mediator less Amperometric Sensor for h2o2
Biosensors and Bioelectronics, 2012Co-Authors: Kuanjung Chen, John Rick, Shihhan Wang, Chandrasekara K Pillai, Chunjern Pan, Chungchiun Liu, Bingjoe HwangAbstract:A new highly catalytic and intensely sensitive Amperometric Sensor based on PtM (where M=Pd, Ir) bimetallic nanoparticles (NPs) for the rapid and accurate estimation of hydrogen peroxide (H(2)O(2)) by electrooxidation in physiological conditions is reported. PtPd and PtIr NPs-decorated multiwalled carbon nanotube nanocatalysts (PtM/MWCNTs) were prepared by a modified Watanabe method, and were characterized by XRD, TEM, ICP, and XAS. The Sensors were constructed by immobilizing PtM/MWCNTs nanocatalysts in a Nafion film on a glassy carbon electrode. Both PtPd/MWCNTs and PtIr/MWCNTs assemblies catalyzed the electrochemical oxidation of H(2)O(2). Cyclic voltammetry characterization measurements revealed that both the PtM (M=Pd, Ir)/MWCNTs/GCE possessed similar electrochemical surface areas (∼0.55 cm(2)), and electron transfer rate constants (∼1.23 × 10(-3)cms(-1)); however, the PtPd Sensor showed a better performance in H(2)O(2) sensing than did the PtIr counterpart. Explanations were sought from XAS measurements to explain the reasons for differences in Sensor activity. When applied to the electrochemical detection of H(2)O(2), the PtPd/MWCNTs/GC electrode exhibited a low detection limit of 1.2 μM with a wide linear range of 2.5-125 μM (R(2)=0.9996). A low working potential (0V (SCE)), fast Amperometric response (<5s), and high sensitivity (414.8 μA mM(-1)cm(-2)) were achieved at the PtPd/MWCNTs/GC electrode. In addition, the PtPd/MWCNTs nanocatalyst Sensor electrode also exhibited excellent reproducibility and stability. Along with these attractive features, the Sensor electrode also displayed very high specificity to H(2)O(2) with complete elimination of interference from UA, AA, AAP and glucose.