共查询到20条相似文献,搜索用时 46 毫秒
1.
Silvia Castrignanò Sheila J. Sadeghi Gianfranco Gilardi 《Analytical and bioanalytical chemistry》2010,398(3):1403-1409
Human flavin-containing monooxygenases are the second most important class of drug-metabolizing enzymes after cytochromes
P450. Here we report a simple but functional and stable enzyme-electrode system based on a glassy carbon (GC) electrode with
human flavin-containing monooxygenase isoform 3 (hFMO3) entrapped in a gel cross-linked with bovine serum albumin (BSA) by
glutaraldehyde. The enzymatic electrochemical responsiveness is characterised by using well-known substrates: trimethylamine
(TMA), ammonia (NH3), triethylamine (TEA), and benzydamine (BZD). The apparent Michaelis–Menten constant (K′M) and apparent maximum current (I′max) are calculated by fitting the current signal to the Michaelis–Menten equation for each substrate. The enzyme-electrode has
good characteristics: the calculated sensitivity was 40.9 ± 0.5 mA mol−1 L cm−2 for TMA, 43.3 ± 0.1 mA mol−1 L cm−2 for NH3, 45.2 ± 2.2 mA mol−1 L cm−2 for TEA, and 39.3 ± 0.6 mA mol−1 L cm−2 for BZD. The stability was constant for 3 days and the inter-electrode reproducibility was 12.5%. This is a novel electrochemical
tool that can be used to investigate new potential drugs against the catalytic activity of hFMO3. 相似文献
2.
Sayed Medhi Ghoreishi Mohsen Behpour Mohammad Hassan Motaghedi Fard 《Journal of Solid State Electrochemistry》2012,16(1):179-189
In this work, we investigate the electrochemical activity of dopamine (DA) and uric acid (UA) using both a bare and a modified
carbon paste electrode as the working electrode, with a platinum wire as the counter electrode and a silver/silver chloride
(Ag/AgCl) as the reference electrode. The modified carbon paste electrode consists of multi-walled carbon nanotubes (>95%)
treated with α-cyclodextrine, resulting in an electrode that exhibits a significant catalytic effect toward the electro-chemical
oxidation of DA in a 0.2-M Britton–Robinson buffer solution (pH 5.0). The peak current increases linearly with the DA concentration
within the molar concentration ranges of 2.0 × 10−6 to 5.0 × 10−5 M and 5.0 × 10−5 to 1.9 × 10−4 M. The detection limit (signal to noise >3) for DA was found to be 1.34 × 10−7 M, respectively. In this work, voltammetric methods such as cyclic voltammetry, chronoamperometry, chronocuolometry, differential
pulse and square wave voltammetry, and linear sweep and hydrodynamic voltammetry were used. Cyclic voltammetry was used to
investigate the redox properties of the modified electrode at various scan rates. The diffusion coefficient (D, cm2 s−1 = 3.05 × 10−5) and the kinetic parameters such as the electron transfer coefficient (α = 0.51) and the rate constant (k, cm3 mol−1 s−1 = 1.8 × 103) for DA were determined using electrochemical approaches. By using differential pulse voltammetry for simultaneous measurements,
we obtained two peaks for DA and UA in the same solution, with the peak separation approximately 136 mV. The average recovery
was measured at 102.45% for DA injection. 相似文献
3.
Reza Ojani Jahan-Bakhsh Raoof Shahla Fathi Sharife Alami-Valikchali 《Journal of Solid State Electrochemistry》2011,15(9):1935-1941
Nickel ions were incorporated in NaY zeolite according to cation exchange mechanism. Then NiY zeolite was used as modifier
for preparation of modified carbon paste electrode. The electrochemical behavior of NiY-modified carbon paste electrode (NiY/CPE)
was studied in alkaline solution using cyclic voltammetry method. Ability of different electrodes containing NiY/CPE, Ni-NiY/CPE,
Ni-NaY/CPE, and Ni/CPE for electrocatalytic oxidation of methanol was compared (three last electrodes prepared by open circuit
accumulation of Ni(II) ions on the surface of NiY/CPE, NaY/CPE, and bare CPE, respectively). Results show that Ni-NiY/CPE
is best catalyst for the electrochemical oxidation of methanol in alkaline solution and both process of earlier Ni ion incorporation
through cation exchange in NaY zeolite and open circuit accumulation of Ni ion on the surface of electrode are essential to
have good catalyst. Effect of graphite–zeolite ratio on electrocatalytic current was studied and 3:1 ratio of graphite–zeolite
was selected as optimum ratio for preparing electrode. Ni-NiY/CPE has very good stability toward the methanol oxidation in
concentration range of 0.005 to 0.5 M. Finally, using chronoamperometric method, the catalytic rate constant (k) for methanol was found to be 1.56 × 104 cm3 mol−1 s−1. 相似文献
4.
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
5.
Bolade O. Agboola Sibulelo L. Vilakazi Kenneth I. Ozoemena 《Journal of Solid State Electrochemistry》2009,13(9):1367-1379
Electrochemistry of water-soluble cobalt(II) tetrasulfophthalocyanine (CoTSPc) electrodeposited on glassy carbon nanotube
pre-modified with acid-functionalized multi-walled carbon nanotubes (MWCNT) is described. Both charge transfer resistances
toward [Fe(CN)6]3−/4− redox probe and electrocatalytic responses toward epinephrine (EP) detection follow the trend: bare GCE < GCE-MWCNT < GCE-CoTSPc < GCE-MWCNT-CoTSPc.
EP analysis was then carried out in details using GCE-MWCNT-CoTSPc. The catalytic rate constant value k
ch = 2.2 × 107 (mol cm−3)−1 s−1 was obtained from rotating disk electrode experiment. Interestingly, GCE-MWCNT-CoTSPc efficiently suppressed the detection
of ascorbic acid (the natural interference of neurotransmitters in physiological conditions) showing good sensitivity (0.132 ± 0.003 A
l mol−1), limit of detection (4.517 × 10−7 mol l−1), and quantification (15.056 × 10−7 mol l−1). In addition, GCE-MWCNT-CoTSPc was conveniently used to determine EP in epinephrine hydrochloric acid injection with recovery
of 101.1 ± 2.2%. 相似文献
6.
Zhirong Mo Faqiong Zhao Fei Xiao Baizhao Zeng 《Journal of Solid State Electrochemistry》2010,14(9):1615-1620
Gold–platinum (AuPt) alloy particles were fabricated directly on multi-walled carbon nanotubes (MWNT)–ionic liquid (i.e.,
trihexyltetradecylphosphonium bis(trifluoromethylsulfonyl)imide, [P6,6,6,14][NTf2]) composite coated glassy carbon electrode (GCE) by electrodeposition method. Scanning electron microscope image showed that
they were well-dispersed nanocluster consisting of smaller nanoparticles, and their size was about 70 nm. X-ray diffraction
experiment showed that they were single-phase alloy nanomaterial, and the calculated composition was consisting with that
obtained by energy dispersive X-ray spectroscopy. The resulting modified electrode (i.e., AuPt–MWNT–[P6,6,6,14][NTf2]/GCE) presented high catalytic activity for the electrochemical oxidation of cysteine. The peak potential of cysteine shifted
to 0.42 V (versus saturated calomel electrode) in 0.1 M H2SO4 and the peak current increased greatly in comparison with that on the corresponding Pt (or Au)–MWNT–[P6,6,6,14][NTf2]/GCE. Under the optimized conditions, the oxidation current of cysteine at 0.45 V was linear to its concentration in the
range of 5.0 × 10−7 ∼ 4.0 × 10−5 M with a sensitivity of 43.8 mA M−1. 相似文献
7.
We used a carbon paste electrode modified with multi-walled carbon nanotubes as a working electrode and studied the electrochemical
behavior of zirconium-alizarin red S complex on it. It was found that the modified electrode exhibited a significant catalytic
effect toward the reduction of free alizarin red S and the complex. The second derivative linear scan voltammograms of the
complex were recorded by a polarographic analyser from 0 to −1000 mV (vs. SCE), and it was found that the complex can be adsorbed
on the surface of the modified electrode, yielding a peak at about −470 mV, corresponding to the reduction of alizarin red
S in the complex. The linear range was found to be 2.0 × 10−11–8.0 × 10−7 mol L−1, and the detection limit was 1.0 × 10−11 mol L−1 (S/N = 3) for 3 min accumulation. The procedure was successfully applied to the determination of trace amounts of zirconium in
the ore samples.
Correspondence: Pei-Hong Deng, Department of Chemistry and Material Science, Hengyang Normal University, Hengyang Hunan 421008,
P.R. China 相似文献
8.
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
9.
Wei-De Zhang Bin Xu Yu-Xiang Hong Yu-Xiang Yu Jian-Shan Ye Jia-Qi Zhang 《Journal of Solid State Electrochemistry》2010,14(9):1713-1718
In this paper, an electrochemical sensor for sensitive and convenient determination of salicylic acid (SA) was constructed
using well-aligned multiwalled carbon nanotubes as electrode material. Compared to the glassy carbon electrode, the electro-oxidation
of SA significantly enhanced at the multiwalled carbon nanotube (MWCNT) electrode. The MWCNT electrode shows a sensitivity
of 59.25 μA mM−1, a low detection limit of 0.8 × 10−6 M and a good response linear range with SA concentration from 2.0 × 10−6 to 3.0 × 10−3 M. In addition, acetylsalicylic acid was determined indirectly after hydrolysis to SA and acetic acid, which simplified the
detection process. The mechanism of electrochemical oxidation of SA at the MWCNT electrode is also discussed. 相似文献
10.
Jian-Shan Ye Hui-Fang Cui Ying Wen Wei De Zhang Guo Qin Xu Fwu-Shan Sheu 《Mikrochimica acta》2006,152(3-4):267-275
Platinum (Pt) nanoparticles were deposited at the surface of well-aligned multi-walled carbon nanotubes (MWNTs) by potential
cycling between +0.50 and −0.70 V at a scanning rate of 50 mV · s−1 in 5 mM Na2PtCl6 solution containing 0.1 M NaCl. The electrocatalytic oxidation of methanol at the nanocomposites of Pt nanoparticles/nanotubes
(Ptnano/MWNTs) has been investigated using 0.2 M H2SO4 as supporting electrolyte. The effects of various parameters, such as Pt loading, concentration of methanol, medium temperature
as well as the stability of Ptnano/MWNTs electrode, have been studied. Compared to glassy carbon electrode, carbon nanotube electrode significantly enhances
the catalytic efficiency of Pt nanoparticles for methanol oxidation. This improvement in performance is due not only to the
high surface area and the fast electron transfer rate of nanotubes but also to the highly dispersed Pt nanoparticles as electrocatalysts
at the tips and the sidewalls of nanotubes. 相似文献
11.
Functionalized polypyrrole films were prepared by incorporation of Fe(CN)6
3− as doping anion during the electropolymerization of pyrrole at a glassy carbon electrode from aqueous solution. The electrochemical
behavior of the Fe(CN)6
3−/Fe(CN)6
4− redox couple in polypyrrole was studied by cyclic voltammetry. An obvious surface redox reaction was observed and dependence
of this reaction on the solution pH was illustrated. The electrocatalytic ability of polypyrrole film with ferrocyanide incorporated
was demonstrated by oxidation of ascorbic acid at the optimized pH of 4 in a glycine buffer. The catalytic effect for mediated
oxidation of ascorbic acid was 300 mV and the bimolecular rate constant determined for surface coverage of 4.5 × 10−8 M cm−2 using rotating disk electrode voltammetry was 86 M−1 s−1. Furthermore, the catalytic oxidation current was linearly dependent on ascorbic acid concentration in the range 5 × 10−4–1.6 × 10−2 M with a correlation coefficient of 0.996. The plot of i
p versus v
1/2 confirms the diffusion nature of the peak current i
p.
Received: 12 April 1999 / Accepted: 25 May 1999 相似文献
12.
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
13.
Slobodan Brinić Marijo Buzuk Marija Bralić Eni Generalić 《Journal of Solid State Electrochemistry》2012,16(4):1333-1341
The development of Cu(II) solid-contact ion-selective electrodes, based on 1,2-di-(o-salicylaldiminophenylthio)ethane as a neutral carrier, is presented. For the electrodes construction, unmodified carbon ink
(type 1 electrode) and polymer membrane-modified carbon ink (type 2 electrode) were used as solid support and transducer layer.
Also, carbon ink composite polymer membrane electrode (type 3 electrode) was prepared. The analytical performance of the electrodes
was evaluated with potentiometry, while bulk and interfacial electrode features were provided with electrochemical impedance
spectroscopy. It is shown that modification of carbon ink with polymer membrane cocktail decreases the bulk contact resistance
of the transducer layer and polymer membrane, thus enhancing the analytical performance of the electrode in terms of sensitivity,
linear range, and stability of potential. The optimized electrodes of types 2 and 3 exhibit a wide linear range with detection
limits of 1.8 × 10−6 and 1.6 × 10−6 M, respectively. They are suitable for determination of Cu2+ in analytical measurements by direct potentiometry and in potentiometric titrations, within pH between 2.3 and 6.5. The electrodes
are selective for Cu2+ over a large number of tested transition and heavy metal ions. 相似文献
14.
Ying Xu Fei Wang Le Wang Fangyuan Zhao Baocheng Yang Baoxian Ye 《Journal of Solid State Electrochemistry》2012,16(4):1473-1480
A novel voltammetric sensor, based on single-walled carbon nanotubes (SWNT) dispersed in Nafion and modified glassy carbon
electrode (GCE), was fabricated and used to determine the trace amounts of dihydromyricetin (DMY). The electrochemical behavior
of DMY at this sensor was investigated in 0.1 mol L−1 sulfuric acid solutions + 0.1 mol L−1 NaCl by cyclic voltammetry and squarewave voltammetry. Compared with bare GCE, the electrode presented an excellent response
of DMY through an adsorption-controlled quasi-reversible process. Under the optimum conditions, the response peak currents
were linear relationship with the DMY concentrations in the range of 1.0 × 10−7–1.0 × 10−5 mol L−1 with a detection limit of 9 × 10−8 mol L−1. Based on this voltammetric sensor, a simple and sensitive electroanalytical method for DMY was proposed and applied to quantitative
determination of DMY in Ampelopsis grossedentata samples. In addition, the oxidation mechanism was proposed and discussed, which could be a reference for the pharmacological
action of DMY in clinical study. 相似文献
15.
S. Majdi A. Jabbari H. Heli H. Yadegari A. A. Moosavi-Movahedi S. Haghgoo 《Journal of Solid State Electrochemistry》2009,13(3):407-416
The electrochemical behavior of ceftriaxone was investigated on a carbon-nanotube-modified glassy carbon (GC-CNT) electrode
in a phosphate buffer solution, pH = 7.40, and the results were compared with those obtained using the unmodified one [glassy
carbon (GC) electrode]. During oxidation of ceftriaxone, an irreversible anodic peak appeared, using both modified and unmodified
electrodes. Cyclic voltammetric studies indicated that the oxidation process is irreversible and diffusion-controlled. The
number of electrons exchanged in the electrooxidation process was obtained, and the data indicated that ceftriaxone is oxidized
via a one-electron step. The results revealed that carbon nanotube promotes the rate of oxidation by increasing the peak current.
In addition, ceftriaxone was oxidized at lower potentials, which thermodynamically is more favorable. These results were confirmed
by impedance measurements. The electron-transfer coefficients and heterogeneous electron-transfer rate constants for ceftriaxone
were reported using both the GC and GC-CNT electrodes. Furthermore, the diffusion coefficient of ceftriaxone was found to
be 2.74 × 10−6 cm2 s−1. Binding of ceftriaxone to human serum albumin forms a kind of electroreactive species. The percentage of interaction of
ceftriaxone with protein was also addressed. A sensitive, simple, and time-saving differential-pulse voltammetric procedure
was developed for the analysis of ceftriaxone, using the GC-CNT electrode. Ceftriaxone can be determined with a detection
limit of 4.03 × 10−6 M with the proposed method. 相似文献
16.
A kind of erbium hexacyanoferrate (ErHCF)-modified carbon ceramic electrodes (CCEs) fabricated by mechanically attaching ErHCF
samples to the surface of CCEs derived from sol–gel technique was proposed. The resulting modified electrodes exhibit well-defined
redox responses with the formal potential of +0.215 V [vs saturated calomel electrode (SCE)] at a scan rate of 20 mV s−1 in 0.5 M KCl (pH 7) solution. The voltammetric characteristics of the ErHCF-modified CCEs were investigated by voltammetry.
Attractively, the ErHCF-modified CCEs presented good electrocatalytic activity with a marked decrease in the overvoltage about
400 mV for l-cysteine oxidation. The calibration plot for l-cysteine determination was linear at 5.0 × 10−6–1.3 × 10−4 M with a linear regression equation of I(A) = 0.558 + 0.148c (μM) (R
2 = 0.9989, n = 20), and the detection limit was 2 × 10−6 M (S/N = 3). At last, the ErHCF-modified CCEs were used for amperometric detection of l-cysteine in real samples. 相似文献
17.
Zhen Wei Zheng Liu Rongrong Jiang Chaoqing Bian Tao Huang Aishui Yu 《Journal of Solid State Electrochemistry》2010,14(6):1045-1050
TiO2 array film fabricated by potentiostatic anodization of titanium is characterized by X-ray diffraction (XRD), scanning electron
microscopy (SEM), and charge–discharge measurements. The XRD results indicated that the TiO2 array is amorphous, and after calcination at 500 °C, it has the anatase form. The pore size and wall thickness of TiO2 nanotube arrays synthesized at different anodization voltages are highly dependent on the applied voltage. The electrochemical
performance of the prepared TiO2 nanotube array as an electrode material for lithium batteries was evaluated by galvanostatic charge–discharge measurement.
The sample prepared at 20 V shows good cyclability but low discharge capacity of 180 mA h cm−3, while the sample prepared at 80 V has the highest discharge capacity of 340 mA h cm−3. 相似文献
18.
A novel modified electrode was fabricated by electropolymerization of acid chrome blue K at a multi-walled carbon nanotubes
modified glassy carbon electrode. The electrode developed was used for simultaneous determination of the isomers of dihydroxybenzene
in environmental samples using first order linear sweep derivative voltammetry with background subtraction. A linear relationship
between peak current and concentration of hydroquinone, catechol and resorcinol was obtained in the range of 1 × 10−6–1 × 10−4 mol L−1, and the detection limits were estimated to be 1 × 10−7, 1 × 10−7 and 9 × 10−8 mol L−1, respectively. The constructed electrode showed excellent reproducibility and stability. Real water samples were analyzed
and satisfactory results were obtained. This method provides a new way of constructing electrodes for environmental and biological
analysis. 相似文献
19.
Mohammad Ali Kamyabi Z. Asgari H. Hosseini Monfared 《Journal of Solid State Electrochemistry》2010,14(9):1547-1553
A carbon past electrode modified with [Mn(H2O)(N3)(NO3)(pyterpy)],
( \textpyterpy = 4¢- ( 4 - \textpyridyl ) - 2,2¢:\text6¢,\text2¢¢- \textterpyridine ) \left( {{\text{pyterpy}} = 4\prime - \left( {4 - {\text{pyridyl}}} \right) - 2,2\prime:{\text{6}}\prime,{\text{2}}\prime\prime - {\text{terpyridine}}} \right) complex have been applied to the electrocatalytic oxidation of nitrite which reduced the overpotential by about 120 mV with
obviously increasing the current response. Relative standard deviations for nitrite determination was less than 2.0%, and
nitrite can be determined in the ranges of 5.00 × 10−6 to 1.55 × 10−2 mol L−1, with a detection limit of 8 × 10−7 mol L−1. The treatment of the voltammetric data showed that it is a pure diffusion-controlled reaction, which involves one electron
in the rate-determining step. The rate constant k′, transfer coefficient α for the catalytic reaction, and diffusion coefficient of nitrite in the solution, D, were found to be 1.4 × 10−2, 0.56× 10−6, and 7.99 × 10−6 cm2 s−1, respectively. The mechanism for the interaction of nitrite with the Mn(II) complex modified carbon past electrode is proposed.
This work provides a simple and easy approach to detection of nitrite ion. The modified electrode indicated reproducible behavior,
anti-fouling properties, and stability during electrochemical experiments, making it particularly suitable for the analytical
purposes. 相似文献
20.
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