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1.
Kumar S. Ashok Wang Sea-Fue Yeh Chun-Ting Lu His-Chuan Yang Jen-Chang Chang Yu-Tsern 《Journal of Solid State Electrochemistry》2010,14(11):2129-2135
In this study, stable and homogenous thin films of multiwalled carbon nanotubes (MWCNTs) were obtained on conducting surface
using ciprofloxacin (CF, fluoroquinolone antibiotic) as an effective-dispersing agent. Further, MWCNTs/CF film modified electrodes
(glassy carbon and indium tin oxide-coated glass electrode) are used successfully to study the direct electrochemistry of
proteins. Here, cytochrome C (Cyt-C) was used as a model protein for investigation. A MWCNTs/CF film modified electrode was
used as a biocompatible material for immobilization of Cyt-C from a neutral buffer solution (pH 7.2) using cyclic voltammetry
(CV). Interestingly, Cyt-C retained its native state on the MWCNTs/CF film. The Cyt-C adsorbed MWCNTs/CF film was characterized
by scanning electron microscopy (SEM), UV–visible spectrophotometry (UV-vis) and CV. SEM images showed the evidence for the
adsorption of Cyt-C on the MWCNTs/CF film, and UV–vis spectrum confirmed that Cyt-C was in its native state on MWCNTs/CF film.
Using CV, it was found that the electrochemical signal of Cyt-C was highly stable in the neutral buffer solution and its redox
peak potential was pH dependent. The formal potential (−0.27 V) and electron transfer rate constant (13 ± 1 s−1) were calculated for Cyt-C on MWCNTs/CF film modified electrode. A potential application of the Cyt-C/MWCNTs/CF electrode
as a biosensor to monitor H2O2 has been investigated. The steady-state current response increases linearly with H2O2 concentration from 2 × 10−6 to 7.8 × 10−5 M. The detection limit for determination of H2O2 has been found to be 1.0 × 10−6 M (S/N = 3). Thus, Cyt-C/MWCNTs/CF film modified electrode can be used as a biosensing material for sensor applications. 相似文献
2.
A new H2O2 biosensor was fabricated on the basis of nanocomposite films of hemoglobin (Hb), silver nanoparticles (AgNPs), and multiwalled
carbon nanotubes (MWNTs)–chitosan (Chit) dispersed solution immobilized on glassy carbon electrode (GCE). The immobilized
Hb displayed a pair of well-defined and reversible redox peaks with a formal potential (E
θ′) of −22.5 mV in 0.1 M pH 7.0 phosphate buffer solution. The apparent heterogeneous electron transfer rate constants (k
s) in the Chit–MWNTs film was evaluated as 2.58 s−1 according to Laviron’s equation. The surface concentration (Γ*) of the electroactive Hb in the Chit–MWNTs film was estimated to be (2.48 ± 0.25) × 10−9 mol cm−2. Meanwhile, the Chit–MWNTs/Hb/AgNPs/GCE demonstrated excellently electrocatalytical ability to H2O2. Its apparent Michaelis–Menten constant (K
Mapp) for H2O2 was 0.0032 mM, showing a good affinity. Under optimal conditions, the biosensors could be used for the determination of H2O2 ranging from 6.25 × 10−6 to 9.30 × 10−5 mol L−1 with a detection limit of 3.47 × 10−7 mol L−1 (S/N = 3). Furthermore, the biosensor possessed rapid response to H2O2 and good stability, selectivity, and reproducibility. 相似文献
3.
Salimi Abollah Noorbakhsh Abdollah Semnani Abolfazl 《Journal of Solid State Electrochemistry》2011,15(9):2041-2052
A simple method was used to fabricate flavin adenine dinucleotide (FAD)/NiOx nanocomposite on the surface of glassy carbon
(GC) electrode. Cyclic voltammetry technique was applied for deposition nickel oxide nanostructures onto GC surface. Owing
to its high biocompatibility and large surface area of nickel oxide nanomaterials with immersing the GC/NiOx-modified electrode
into FAD solution for a short period of time, 10–140 s, a stable thin layer of the FAD molecules immobilized onto electrode
surface. The FAD/NiOx films exhibited a pair of well-defined, stable, and nearly reversible CV peaks at wide pH range (2–10).
The formal potential of adsorbed FAD onto nickel oxide nanoparticles film, E
o′ vs. Ag/AgCl reference electrode is −0.44 V in pH 7 buffer solutions was similar to dissolved FAD and changed linearly with
a slope of 58.6 mV/pH in the pH range 2–10. The surface coverage and heterogeneous electron transfer rate constant (k
s
) of FAD immobilized on NiOx film glassy carbon electrode are 4.66 × 10−11 mol cm−2 and 63 ± 0.1 s−1, indicating the high loading ability of the nickel oxide nanoparticles and great facilitation of the electron transfer between
FAD and nickel oxide nanoparticles. FAD/NiOx nanocomposite-modified GC electrode shows excellent electrocatalytic activity
toward S2O82− reduction at reduced overpotential. Furthermore, rotated modified electrode illustrates good analytical performance for amperometric
detection of S2O82−. Under optimized condition, the concentration calibration range, detection limit, and sensitivity were 3 μM–1.5 mM, 0.38 μM
and 16.6 nA/μM, respectively. 相似文献
4.
Ozone (O3) has been electrochemically generated on PbO2-loaded Pt screens (PbO2/Pts) at 25 °C from H2SO4 solutions. The PbO2/Pts electrodes were electrochemically and morphologically characterized by cyclic voltammetry and scanning electron microscopy
(SEM), respectively. Different loadings of PbO2 and different acid concentrations (C
acid) were used in this study. Higher efficiency (8%) for O3 electrogeneration was obtained at an applied potential of 1.8 V, higher C
acid, and loading density of PbO2 ≥ 9.3 μmol cm−2 (of Pt screen) at room temperature. The stability of the prepared electrode was examined under the present experimental conditions.
SEM images and current transients showed reasonable electrochemical and mechanical stability of the PbO2/Pts. The data were discussed in the light of results obtained on planar Pt electrode at similar conditions. 相似文献
5.
A novel hydrogen peroxide (H2O2) biosensor was developed by immobilizing hemoglobin on the gold colloid modified electrochemical pretreated glassy carbon
electrode (PGCE) via the bridging of an ethylenediamine monolayer. This biosensor was characterized by UV-vis reflection spectroscopy
(UV-vis), electrochemical impendence spectroscopy (EIS) and cyclic voltammetry (CV). The immobilized Hb exhibited excellent
electrocatalytic activity for hydrogen peroxide. The Michaelis–Menten constant (K
m) was 3.6 mM. The currents were proportional to the H2O2 concentration from 2.6 × 10−7 to 7.0 × 10−3 M, and the detection limit was as low as 1.0 × 10−7 M (S/N = 3). 相似文献
6.
Thermally two-dimensional lattice graphene (GR) and biocompatibility chitosan (CS) act as a suitable support for the deposition
of palladium nanoparticles (PdNPs). A novel hydrogen peroxide (H2O2) biosensor based on immobilization of hemoglobin (Hb) in thin film of CS containing GR and PdNPs was developed. The surface
morphologies of a set of representative membranes were characterized by means of scanning electron microscopy and showed that
the PdNPs are of a sphere shape and an average diameter of 50 nm. Under the optimal conditions, the immobilized Hb showed
fast and excellent electrocatalytic activity to H2O2 with a small Michaelis–Menten constant of 16 μmol L−1, a linear range from 2.0 × 10−6 to 1.1 × 10−3 mol L−1, and a detection limit of 6.6 × 10−7 mol L−1. The biosensor also exhibited other advantages, good reproducibility, and long-term stability, and PdNPs/GR–CS nanocomposites
film would be a promising material in the preparation of third generation biosensor. 相似文献
7.
This paper describes the use of an aluminum electrode plated by metallic palladium and modified by Prussian blue (PB/Pd-Al)
in the electrocatalytic reduction of hydrogen peroxide (H2O2). The effect of pH on the electroreduction of H2O2 on the modified electrode is investigated and a simple irreversible reduction pathway is suggested. The electroreduction
kinetics including transfer coefficient α, potential-dependent charge transfer rate constants k
f, and diffusion coefficient D are estimated by means of forced hydrodynamic voltammetry using a rotating disk PB/Pd-Al electrode. The mean values obtained
for kinetics are 0.38, 10−2 cm−1, and 7.6 × 10−6 cm2 s−1, respectively. The long-term stability of the modifying layers on the Al substrate was studied. 相似文献
8.
The Fe3O4-Prussian blue (PB) nanoparticles with core-shell structure have been in situ prepared directly on a nano-Fe3O4-modified glassy carbon electrode by cyclic voltammetry (CV). First, the magnetic nano-Fe3O4 particles were synthesized and characterized by X-ray diffraction. Then, the properties of the Fe3O4-PB nanoparticles were characterized by CV, electrochemical impedance spectroscopy, and superconducting quantum interference
device. The resulting core-shell Fe3O4-PB-modified electrode displays a dramatic electrocatalytic ability toward H2O2 reduction, and the catalytic current was a linear function with the concentration of H2O2 in the range of 1 × 10−7~5 × 10−4 mol/l. A detection limit of 2 × 10−8 (s/n = 3) was determined. Moreover, it showed good reproducibility, enhanced long-term stability, and potential applications in
fields of magnetite biosensors. 相似文献
9.
Shuhu Xiao Jiuhui Qu Huijuan Liu Xu Zhao Dongjin Wan 《Journal of Solid State Electrochemistry》2009,13(12):1959-1964
Titanium oxide nanotube electrodes were successfully prepared by anodic oxidation on pure Ti sheets in 0.5 wt.% NH4F + 1 wt.% (NH4)2SO4 + 90 wt.% glycerol mixed solutions. Nanotubes with diameter 40–60 nm and length 7.4 μm were observed by field emission scanning
electron microscope. The electrochemical and photoelectrochemical characteristics of TiO2 nanotube electrode were investigated using linear polarization and electrochemical impedance spectroscopy techniques. The
open-circuit potential dropped markedly under irradiation and with the increase of Cl− concentrations. A saturated photocurrent of approximately 1.3 mA cm−2 was observed under 10-W low-mercury lamp irradiation in 0.1 M NaCl solution, which was much higher than film electrode. Meanwhile,
the highest photocurrent in NaCl solution implied that the photogenerated holes preferred to combine with Cl−. Thus, a significant synergetic effect on active chlorine production was observed in photoelectrocatalytic processes. Furthermore,
the generation efficiency for active chlorine was about two times that using TiO2/Ti film electrode by sol–gel method. Finally, the effects of initial pH and Cl− concentration were also discussed. 相似文献
10.
Falong Jia Chuanfang Yu Jingming Gong Lizhi Zhang 《Journal of Solid State Electrochemistry》2008,12(12):1567-1571
Prussian blue-modified nanoporous gold film (PB-NPGF) electrode was fabricated in this study. The fabrication was realized
through electrodeposition of Prussian blue nanoparticles on the skeleton of a nanoporous gold film electrode without destroying
the porous structure of NPGF electrode. The resulting PB-NPGF composite electrode showed very high electrocatalytic activity,
repeatability, and stability to the reduction of H2O2. For instance, its activity was about twenty times that of the PB-modified polished gold electrode. More importantly, the
sensitivity of the PB-NPGF composite electrode reaches as high as 10.6 μA μM−1 cm−2. This PB-NPGF composite electrode is very promising in the fields of catalysis, analysis, and so on. 相似文献
11.
E. Nazaruk K. Sadowska J. F. Biernat J. Rogalski G. Ginalska R. Bilewicz 《Analytical and bioanalytical chemistry》2010,398(4):1651-1660
Nanostructured bioelectrodes were designed and assembled into a biofuel cell with no separating membrane. The glassy carbon
electrodes were modified with mediator-functionalized carbon nanotubes. Ferrocene (Fc) and 2,2′-azino-bis (3-ethylbenzothiazoline-6-sulfonate)
diammonium salt (ABTS) bound chemically to the carbon nanotubes were found useful as mediators of the enzyme catalyzed electrode
processes. Glucose oxidase from Aspergillus niger AM-11 and laccase from Cerrena unicolor C-139 were incorporated in a liquid-crystalline matrix-monoolein cubic phase. The carbon nanotubes–nanostructured electrode
surface was covered with the cubic phase film containing the enzyme and acted as the catalytic surface for the oxidation of
glucose and reduction of oxygen. Thanks to the mediating role of derivatized nanotubes the catalysis was almost ten times
more efficient than on the GCE electrodes: catalytic current of glucose oxidation was 1 mA cm−2 and oxygen reduction current exceeded 0.6 mA cm−2. The open circuit voltage of the biofuel cell was 0.43 V. Application of carbon nanotubes increased the maximum power output
of the constructed biofuel cell to 100 μW cm−2 without stirring of the solution which was ca. 100 times more efficient than using the same bioelectrodes without nanotubes
on the electrode surface. 相似文献
12.
An anodic stripping voltammetric procedure for the determination of Cu(II) at an in situ-plated stannum film electrode (SnFE)
was described. The results indicated that the SnFE had an attractive electroanalytical performance, with two distinct voltammetric
stripping signals for copper and stannum, and showed the superior advantage for the determination of copper compared with
the bismuth film electrode. Several experimental parameters were optimized. The SnFE exhibited highly linear behavior in the
concentration range from 1.0 to 100.0 μg L−1 of Cu(II) (r = 0.994) with the detection limit of 0.61 μg L−1 (S/N = 3), and the relative standard deviation for a solution containing 40.0 μg L−1 Cu(II) was 2.2% (n = 8). The procedure has been successfully applied for the determination of Cu(II) in lake water sample. 相似文献
13.
Timothy J. Johnson Robert L. Sams Sarah D. Burton Thomas A. Blake 《Analytical and bioanalytical chemistry》2009,395(2):377-386
We report quantitative infrared spectra of vapor-phase hydrogen peroxide (H2O2) with all spectra pressure-broadened to atmospheric pressure. The data were generated by injecting a concentrated solution
(83%) of H2O2 into a gently heated disseminator and diluting it with pure N2 carrier gas. The water vapor lines were quantitatively subtracted from the resulting spectra to yield the spectrum of pure
H2O2. The results for the ν6 band strength (including hot bands) compare favorably with the results of Klee et al. (J Mol. Spectrosc. 195:154, 1999) as well as with the HITRAN values. The present results are 433 and 467 cm-2 atm−1 (±8 and ±3% as measured at 298 and 323 K, respectively, and reduced to 296 K) for the band strength, matching well the value
reported by Klee et al. (S = 467 cm−2 atm−1 at 296 K) for the integrated band. The ν1 + ν5 near-infrared band between 6,900 and 7,200 cm−1 has an integrated intensity S = 26.3 cm−2 atm−1, larger than previously reported values. Other infrared and near-infrared bands and their potential for atmospheric monitoring
are discussed. 相似文献
14.
The electrochemical solid phase micro-extraction of salicylic acid (SA) at graphite-epoxy-composed solid electrode surface
was studied by cyclic voltammetry. SA was oxidized electrochemically in pH 12.0 aqueous solution at 0.70 V (vs. saturated
calomel electrode) for 7 s. The oxidized product shows two surface-controlled reversible redox couples with two proton transferred
in the pH range of 1.0∼6.0 and one proton transferred in the pH range of 10.0∼13.0 and is extracted on the electrode surface
with a kinetic Boltzman function of i
p = 3.473–4.499/[1 + e(t − 7.332)/6.123] (χ
2 = 0.00285 μA). The anodic peak current of the extracted specie in differential pulse voltammograms is proportional to the
concentration of SA with regression equation of i
p = −5.913 + 0.4843 c (R = 0.995, SD = 1.6 μA) in the range of 5.00∼200 μM. The detection limit is 5.00 μM with RSD of 1.59% at 60 μM. The method
is sensitive and convenient and was applied to the detection of SA in mouse blood samples with satisfactory results. 相似文献
15.
Ali Eftekhari 《Mikrochimica acta》2003,141(1-2):15-21
The electrocatalytic activity of an aluminum microelectrode modified with cobalt hexacyanoferrate film is described. A simple
method was used for the preparation of the modified microelectrode. The modified microelectrode exhibits good electrocatalytic
properties for electrochemical reduction of hydrogen peroxide. The effect of solution pH and applied potential on the electrocatalytic
properties of the modified microelectrode is investigated. The results show that the best potential for the detection of hydrogen
peroxide is 0.0 vs. SCE for better response and decrease of interferences. Due to the microelectrode scale, it can be used for the determination
of small amounts of H2O2. The calibration plot is linear up to 1.7 mM (r = 0.988) with a response time of 5.1 s. The detection limit of the microelectrode as H2O2 sensor is 2 × 10−7 M. The sensivity of the H2O2 sensor is 225.6 nA mmol−1 and RSD of this sensor is less than 2.3%. In addition, effects of possible interferences and possibility of the sensor for
real samples is investigated. The present work shows the potential of the proposed method for the fabrication of modified
electrodes, as it can be used to employ for different purposes in micro scale.
Received June 20, 2001; accepted June 14, 2002 相似文献
16.
The electrode characteristics and selectivities of PVC-based thiocyanate selective polymeric membrane electrode (PME) incorporating
the newly synthesized zinc complex of 6,7:14,15-Bzo2-10,11-(4-methylbenzene)-[15]-6,8,12,14-tetraene-9,12-N2-1,5-O2 (I
1
) and zinc complex of 6,7:14,15-Bzo2-10,11-(4-methylbenzene)-[15]-6,14-diene-9,12-dimethylacrylate-9,12-N2-1,5-O2 (I
2
) are reported here. The best response was observed with the membrane having a composition of I2:PVC:o-NPOE:HTAB in the ratio of 6:33:59:2 (w/w; milligram). This electrode exhibited Nernstian slope for thiocyanate ions over working concentration range of 4.4 × 10−7 to 1.0 × 10−2 mol L−1 with detection limit of 2.2 × 10−7 mol L−1. The performance of this electrode was compared with coated graphite electrode (CGE), which showed better response characteristics
w.r.t Nernstian slope 59.0 ± 0.2 mV decade−1 activity, wide concentration range of 8.9 × 10−8 to 1.0 × 10−2 mol L−1 and detection limit of 6.7 × 10−8 mol L−1. The response time for CGE and PME was found to be 8 and 10 s, respectively. The proposed electrode (CGE) was successfully
applied to direct determination of thiocyanate in biological and environmental samples and also as indicator electrode in
potentiometric titration of SCN− ion. 相似文献
17.
The electrocatalytic oxidation of quinine sulfate (QS) was investigated at a glassy carbon electrode, modified by a gel containing
multiwall carbon nanotubes (MWCNTs) and room-temperature ionic liquid of 1-Butyl-3-methylimidazolium hexafluorophate (BMIMPF6) in 0.10 M of phosphate buffer solution (PBS, pH 6.8). It was found that an irreversible anodic oxidation peak of QS with
E
pa as 0.99 V appeared at MWCNTs-RTIL/glassy carbon electrode (GCE). The electrode reaction process was a diffusion-controlled
one and the electrochemical oxidation involved two electrons transferring and two protons participation. Furthermore, the
charge-transfer coefficient (α), diffusion coefficient (D), and electrode reaction rate constant (k
f) of QS were found to be 0.87, 7.89 × 10−3 cm2⋅s−1 and 3.43 × 10−2 s−1, respectively. Under optimized conditions, linear calibration curves were obtained over the QS concentration range 3.0 × 10−6 to 1.0 × 10−4 M by square wave voltammetry, and the detection limit was found to be 0.44 μM based on the signal-to-noise ratio of 3. In
addition, the novel MWCNTs-RTIL/GCE was characterized by the electrochemical impedance spectroscopy and the proposed method
has been successfully applied in the electrochemical quantitative determination of quinine content in commercial injection
samples and the determination results could meet the requirement. 相似文献
18.
Audrey Sassolas Loïc J. Blum Béatrice D. Leca-Bouvier 《Analytical and bioanalytical chemistry》2009,394(4):971-980
Performant reagentless electrochemiluminescent (ECL) (bio)sensors have been developed using polymeric luminol as the luminophore.
The polyluminol film is obtained by cyclic voltammetry (CV) on a screen-printed electrode either in a commonly used H2SO4 medium or under more original near-neutral buffered conditions. ECL responses obtained after performing polymerization either
at acidic pH or at pH 6 have been compared. It appears that polyluminol formed in near-neutral medium gives the best responses
for hydrogen peroxide detection. Polymerization at pH 6 by cyclic voltammetry gives a linear range extending from 8 × 10−8 to 1.3 × 10−4 M H2O2 concentrations. Based on this performant sensor for hydrogen peroxide detection, an enzymatic biosensor has been developed
by associating the polyluminol film with an H2O2-producing oxidase. Here, choline oxidase (ChOD) has been chosen as a model enzyme. To develop the biosensor, luminol has
been polymerized at pH 6 by CV, and then an enzyme-entrapping matrix has been formed on the above modified working electrode.
Different biological (chitosan, agarose, and alginate) and chemical (silica gels, photopolymers, or reticulated matrices)
gels have been tested. Best performances have been obtained by associating a ChOD-immobilizing photopolymer with the polyluminol
film. In this case, choline can be detected with a linear range extending from 8 × 10−8 to 1.3 × 10−4 M.
This paper is based on the results presented in a poster that received a Poster Award on the occasion of XIII International
Symposium on Luminescence Spectrometry in Bologna, Italy, on September, 7th-11th, 2008. 相似文献
19.
Eduardo Marafon Lauro T. Kubota Yoshitaka Gushikem 《Journal of Solid State Electrochemistry》2009,13(3):377-383
SiO2/ZrO2/C carbon ceramic material with composition (in wt%) SiO2 = 50, ZrO2 = 20, and C = 30 was prepared by the sol–gel-processing method. A high-resolution transmission electron microscopy image
showed that ZrO2 and the graphite particles are well dispersed inside the matrix. The electrical conductivity obtained for the pressed disks
of the material was 18 S cm−1, indicating that C particles are also well interconnected inside the solid. An electrode modified with flavin adenine dinucleotide
(FAD) prepared by immersing the solid SiO2/ZrO2/C, molded as a pressed disk, inside a FAD solution (1.0 × 10−3 mol L−1) was used to investigate the electrocatalytic reduction of bromate and iodate. The reduction of both ions occurred at a peak
potential of −0.41 V vs. the saturated calomel reference electrode. The linear response range (lrr) and detection limit (dl)
were: BrO3
−, lrr = 4.98 × 10−5–1.23 × 10−3 mol L−1 and dl = 2.33 μmol L−1; IO3
−, lrr = 4.98 × 10−5 up to 2.42 × 10−3 and dl = 1.46 μmol L−1 for iodate. 相似文献
20.
Hybrid silver/phosphophomolybdate/polyaniline (Ag/PMo12/PAni) was obtained through one pot synthesis, and then, it was successfully
fabricated on the glassy carbon electrode by simple casting method for electrocatalytic reduction of hydrogen peroxide (H2O2). The cyclic voltammetric studies of the Ag/PMo12/PAni hybrid electrode suggest that the electronic properties of the phosphomolybdate
are retained even after the formation of hybrid material and in addition effectively electro-catalyzing the reduction of H2O2 with a less negative over potential. The Ag/PMo12/PAni-modified electrode showed the lowest detection limit (750 nM) for
H2O2 reduction among the hybrid-modified electrodes already reported with a sensitivity of 4.398 nA μM−1. The prepared hybrid material was well characterized by using UV, XRD and TEM analysis. 相似文献