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1.
Ahmad Nozad Golikand Mehdi Asgari Mohammad Ghannadi Maragheh Elaheh Lohrasbi 《Journal of Applied Electrochemistry》2009,39(1):65-70
A multi-wall carbon nanotube (MWNT) modified glassy carbon electrode (GCE) is described for the measurement of trace levels
of uranium by anodic stripping voltammetry. In a pH 4.4 NaAc-Hac buffer containing 0.010 mol L−1 Mg(NO3)2, UO2
2+ was adsorbed onto the surface of a MWNT film coated glassy carbon electrode and then reduced at −0.40 V vs. Ag/AgCl. During
the positive potential sweep the reduced uranium was oxidized and a well-defined stripping peak appeared at +0.20 V vs. Ag/AgCl.
Low concentrations of Mg2+ significantly enhanced the stripping peak currents since they induced UO2
2+ to adsorb at the electrode surface. The response was linear up to 1.2 × 10−7 mol L−1 and the relative standard deviation at 2.0 × 10−8 mol L−1 uranium was 5.2%. Potential interferences were examined. The attractive behavior of the new “mercury-free” uranium sensor
holds promise for on-site environmental and industrial monitoring of uranium. 相似文献
2.
A carbon nanotube/Nafion composite film modified electrode is described for the sensitive and convenient determination of
Pb2+. In the presence of 1% Nafion, multi-walled carbon nanotubes (MWNT) were successfully dispersed into ethanol by ultrasonication.
After evaporating the ethanol, a MWNT/Nafion composite film-modified electrode was achieved. The resulting MWNT/Nafion film
modified electrode possesses high cation exchange capacity, large surface area, strong adsorption ability and catalytic activity.
Compared with the unmodified electrode and Nafion film-modified electrode, the MWNT/Nafion film-modified electrode remarkably
increases the stripping peak current of Pb2+. Furthermore, the influences of supporting electrolyte, volume of MWNT/Nafion suspension, accumulation potential and accumulation
time were investigated. The striping peak current of Pb2+ is proportional to its concentration over the range 8.0 × 10−8 to 6.0 × 10−6 mol L−1. The limit of detection (S/N = 3) is as low as 5.0 × 10−9 mol L−1. Finally, this newly developed method was used to determine Pb2+ in water samples. 相似文献
3.
The electrocatalytic reduction of hydrogen peroxide (H2O2) has been studied at nanostructured copper (Cunano) modified glassy carbon (GC/Cunano) electrode in phosphate buffer (pH 7.2). The electrical properties of GC/Cunano modified electrodes were studied by electrochemical impedance spectroscopy (EIS). Surface and electrochemical characterization
were carried out by using atomic force microscopy (AFM) and cyclic voltammetry. A well-defined H2O2 reduction signal, which is due to mediation of a surface active site redox transition exhibits at the GC/Cunano electrode. The Cunano is acting as a bridge without the aid of any other electron mediator, which enables the direct electron transfer between
the modified electrode and the substrate. The results are compared with bulk copper macroelectrode and emphasized the efficiency
of the Cunano modified electrode. Systematic investigations were made to optimize the experimental parameter, such as applied potential
(Eapp) for copper electrodeposition. The calibration curve obtained from chronoamperometric studies was found to be linear in the
range 0.5 to 8.0 μM H2O2 with a detection limit of ca.10 nM (S/N = 3) at the GC/Cunano electrode. The modified electrode is stable for 1 week in phosphate buffer after repetitive measurements. 相似文献
4.
A modified electrode, nickel(II)-morin complex modified multi-wall carbon nanotube paste electrode (Ni(II)-MR-MWCNT-PE), has
been fabricated by electrodepositing Ni(II)-MR complex on the surface of MWCNT-PE in alkaline solution. The Ni(II)-MR-MWCNT-PE
exhibits the characteristic of improved reversibility and enhanced current responses of the Ni(III)/Ni(II) couple compared
with Ni(II)-MR complex modified carbon paste electrode (CPE). It also shows better electrocatalytic activity toward the oxidation
of hydroxylamine than the Ni(II) modified MWCNT-PE (Ni(II)-MWCNT-PE) and Ni(II)-MR-CPE. Kinetic parameters such as the electron
transfer coefficient α, rate constant k
s of the electrode reaction and the catalytic rate constant k
cat of the catalytic reaction are determined. Moreover, the catalytic currents present linear dependence on the concentration
of hydroxylamine from 2.5 × 10−6 to 4.0 × 10−4 mol L−1 by amperometry. The detection limit and sensitivity are 8.0 × 10−7 mol L−1 and 56.2 mA L mol−1, respectively. The modified electrode for hydroxylamine determination is of the property of simple preparation, good stability,
fast response and high sensitivity. 相似文献
5.
Jiadong Huang Xiuming Zhang Su Liu Qing Lin Xiaorui He Xianrong Xing Wenjing Lian 《Journal of Applied Electrochemistry》2011,41(11):1323-1328
A novel bisphenol A (BPA) sensor based on amperometric detection has been developed by using molecularly imprinted polymers
(MIPs) and gold nanoparticles. The sensitive layer was prepared by electropolymerization of 2-aminothiophenol on a gold nanoparticles-modified
glassy carbon electrode in the presence of BPA as a template. Cyclic voltammetry was used to monitor the process of electropolymerization.
The properties of the layer were studied in the presence of Fe(CN)6
3−/Fe(CN)6
4− redox couples. The template and the non-binding molecules were removed by washing with H2SO4 (0.65 mol L−1) solution. The linear response range of the sensor was between 8.0 × 10−6–6.0 × 10−2 mol L−1, with a detection limit of 1.38 × 10−7 mol L−1 (S/N = 3). The proposed MIPs sensor exhibited good selectivity for BPA. The stability and repeatability of the MIPs senor were
found to be satisfactory. The results from real sample analysis confirmed the applicability of the MIPs sensor to quantitative
analysis. 相似文献
6.
Vu Thi Huong Toshinori Shimanouchi Do Phuc Quan Hiroshi Umakoshi Pham Hung Viet Ryoichi Kuboi 《Journal of Applied Electrochemistry》2009,39(10):2035-2042
The possible use of an electrode modified with electroactive conductive poly(3-methylthiophene) (PMeT)/Nafion as a chemical
sensor was investigated for the voltammetric analysis of Dopamine (DA). The electrochemical behavior of dopamine was examined
by cyclic voltammetry (CV) and differential pulse voltammetry (DPV) techniques. By using a PMeT-modified glassy carbon (GC/PMeT)
electrode, DA and Ascorbic Acid (AA) signals could be separated but the AA at high concentrations still caused significant
interference by overlapping the DA peak. In comparison to the GC/PMeT electrode, the glassy carbon (GC/Nafion/PMeT) electrode
modified with hybrid film Nafion/PMeT was found to permit a superior separation by shifting the oxidation of AA peak toward
the less positive potential. The DPV curves for a mixture of DA and AA at an GC/Nafion/PMeT electrode in a 0.1 M H2SO4 solution showed peaks of DA and AA, at 0.45 and 0.21 V, respectively, indicating that the difference in the oxidation potential
was 240 mV. In the 0.1 M H2SO4 solution, the oxidation peak current on the differential pulse voltammograms for the GC/PMeT electrode increased linearly
with the concentration of DA in the range 1 × 10−6 to 1 × 10−3 M, and the oxidation peak current on the differential pulse voltammograms for the GC/Nafion/PMeT electrode in the range 5 × 10−7 to 2 × 10−4 M. The DA detection sensitivity of the GC/Nafion/PMeT electrode (26.7 μA μM−1 cm−2) was 22 times higher than that of the GC/PMeT electrode (1.21 μA μM−1 cm−2). 相似文献
7.
Hao Tang Guang-zhi Hu Sheng-xiang Jiang Xia Liu 《Journal of Applied Electrochemistry》2009,39(12):2323-2328
The electrocatalytic behavior of uric acid has been investigated with a glassy carbon electrode modified with p-aminobenzene sulfonic acid through electrochemical polymerization. This resulting electrode shows an excellent electrocatalytic
response to uric acid and ascorbic acid, with a peak-to-peak separation of 0.267 V in a 0.1 mol L−1 phosphate buffer solution (PBS) at pH 7.0. These results indicate that the proposed electrode can eliminate the serious interference
of ascorbic acid, which coexists with uric acid in body fluids. Differential pulse voltammetry (DPV) was used for detecting
uric acid with selectivity and sensitivity. The anodic peak current of uric acid was proportional to its concentration in
the range of 1.2 × 10−7–8.0 × 10−4 mol L−1, with a detection limit of 4.0 × 10−8 mol L−1. The proposed method has been applied with satisfactory results to the determination of uric acid in human urine without
any pretreatment. 相似文献
8.
Quanpeng Chen Shiyun Ai Qiang Ma Huanshun Yin 《Journal of Applied Electrochemistry》2010,40(7):1379-1385
Determination of dopamine (DA) in the absence and presence of ascorbic acid (AA) by ferrocenyl-tethered PAMAM G3 dendrimers
(Fc-D) modified glassy carbon electrode (GCE) was reported. The modified electrode was characterized with cyclic voltammetry
(CV) and electrochemical impedance spectroscopy (EIS). Factors influencing the detection processes were optimized and kinetic
parameters were calculated. The sensor exhibited excellent catalytic activities for the oxidation–reduction reactions of DA
and eliminated the interference of AA. Under optimal condition, the linear range of 1 × 10−5–1.5 × 10−3 mol L−1 and the detection limit of 4.7 × 10−6 mol L−1 was obtained. This study provides a new idea for the determination of DA in the presence of AA. 相似文献
9.
A simple and convenient method is described for voltammetric determination of thiamazole, a commonly used anti-hyperthyroid
drug, based on its electrochemical oxidation at a multi-wall carbon nanotube modified glassy carbon electrode. Under optimized
conditions, the proposed method exhibited acceptable analytical performances in terms of linearity (over the concentration
range from 1.0 × 10−7 to 5.0 × 10−4 mol L−1, r = 0.9983), detection limit (3.0 × 10−8 mol L−1) and reproducibility (RSD = 2.64%, n = 10, for 5.0 × 10−5 mol L−1 thiamazole). To further validate its possible application, the method was used for the quantification of thiamazole in pharmaceutical
formulations and biological fluids. 相似文献
10.
A novel technique is utilized to detect trace amounts of phloroglucinol. In pH 5.0, 0.1 mol L−1 HAc–NaAc buffer solution, phloroglucinol exhibited a stable and sensitive oxidation signal at a glassy carbon electrode modified
with multi-wall carbon nanotube. By using the surfactant cetyl pyridinium chloride, the electrochemical response was greatly
enhanced. The mechanism was systematically explored. In the range 9.0 × 10−7–3.0 × 10−4 mol L−1, the oxidation peak currents of phloroglucinol have a linear relationship with concentration: the limit of detection was
estimated to be 2.5 × 10−7 mol L−1 (S/N = 3). The method was adopted to detect the content of phloroglucinol injection, and the recovery was from 97.5% to 103.0%. 相似文献
11.
Braunite phase manganese oxide is naturally available in manganese–silicate rocks with minor amount of silicate content. New
synthetic route is attempted to prepare the manganese oxide nanoparticle and silica incorporated manganese oxide nanocomposite
in the present study. XRD patterns reveal the braunite phase formation for as synthesized manganese oxide nanocomposite and
silica incorporated MnO2 nanocomposite materials. Improved BET surface area values are achieved by one step surfactant assisted method (i.e., 82 and
151 m2/g) compared to conventional route prepared manganese oxide nanomaterial. Flaky pastry type morphology was observed for as
synthesized Si–MnO2 nanocomposites. Cyclic voltammetry studies predict the electrocatalytic activity of manganese oxide nanoparticle and Si–MnO2 nanocomposite in presence of electroactive redox couple. Si–MnO2 nanocomposite modified glassy carbon (GC) electrode shows the effective electroactive response in presence of Fe2+/Fe3+ redox couple at 0.69 V with current density of 0.343 × 10−5 A/cm2 compared to manganese oxide nanoparticle modified GC electrode. The biosensor responses for ascorbic acid have been tested
in the present study and manganese oxide nanoparticle modified GC electrode shows effective response at low concentration
of (1 × 10−5 M) ascorbic acid in phosphate buffer solution. Manganese oxide nanoparticle modified electrode shows the better response
with current density value of 0.115 × 10−5 A/cm2 compared to Si–MnO2 nanocomposite. 相似文献
12.
Titanium (IV) Phosphate copper hexacyanoferrate composite (TiPhCuHCF) was prepared using a new methodology for the synthesis.
A preliminary characterization of the precursor and resulting materials was defined using spectroscopic and chemical techniques.
The cyclic voltammogram of the modified electrode containing TiPhCuHCF exhibited two redox couples. The first and second redox
couples present a formal potential (E
θ′) of 0.18 and 0.76 V and were ascribed to the Cu+/Cu2+ (E
θ′)1 and Fe2+(CN)6/Fe3+(CN)6 (E
θ′)2 processes, respectively. In a preliminary study, the peak located at 0.76 V displays a sensitive response to N-acetylcysteine. The modified graphite paste electrode showed a linear range from 1.0 × 10−5 to 7.0 × 10−4 mol L−1 for the determination of N-acetylcysteine with a limit detection of 6.96 × 10−5 mol L−1 and relative standard deviation of ± 5% (n = 3) and amperometric sensitivity of 24.79 × 10−3 A mol L−1. The modified electrode was electrochemically stable and showed good reproducibility. 相似文献
13.
Yuxue Dai Nuo Zhang Dan Wu Jian Yang Jie Zhao Guodong Chen Wei Zhao Rui Feng Bin Du Qin Wei 《Journal of Inorganic and Organometallic Polymers and Materials》2011,21(4):871-875
In this study, a sensor for the sensitive determination of ascorbic acid (AA) has been fabricated based on meso-tetra-(3,5-dibromo-4-hydroxydroxyphenyl) porphyrin copper (II) (T(DBHP)P-Cu) modified Au electrode through l-cysteine (l-cys). Firstly, l-cys modified Au electrode was prepared through self-assembled technology. Then T(DBHP)P-Cu was adsorbed on l-cys/Au through covalent binding. The fabrication process and electrochemical behavior of T(DBHP)P-Cu/l-cys/Au were studied by cyclic voltammetry and differential pulse voltammetry. The results showed that AA exhibited good electrochemical
activity at T(DBHP)P-Cu/l-cys/Au. The oxidation peak current increased linearly with AA concentration in the range of 1.00 × 10−3–1.02 × 10−5 mol L−1 with a detection limit of 5.41 × 10−7 mol L−1. Additionally, the modified electrode could be applied to the detect AA in practical samples. 相似文献
14.
Simple and eco-friendly electro deposition method was employed for the fabrication of Au–Ag bimetallic nanoparticles modified
glassy carbon electrode. Nano Au–Ag film modified glassy carbon electrode surface morphology has been examined using atomic
force microscopy. Electrodeposited Au–Ag bimetallic nanoparticles were found in the average size range of 15–50 nm. The electrochemical
investigations of nano Au–Ag/1-butyl-3-methylimidazolium tetrafluoroborate-nafion film have been carried out using cyclic
voltammetry and electrochemical impedance spectroscopy. The nano Au–Ag/1-butyl-3-methylimidazolium tetrafluoroborate-nafion
film modified glassy carbon electrode holds the good electrochemical behavior and stability in pH 7.0 phosphate buffer solutions.
The nano Au–Ag/1-butyl-3-methylimidazolium tetrafluoroborate-nafion modified glassy carbon electrode was successfully employed
for the detection of H2O2 in the linear range of 1–250 μM in lab samples, and 1 × 10−3–2 × 10−2 M in real samples, respectively. 相似文献
15.
L. Gomes R. G. Freitas G. R. P. Malpass E. C. Pereira A. J. Motheo 《Journal of Applied Electrochemistry》2009,39(1):117-121
Electrochemical decolourisation of Reactive Orange 16 was carried out in an electrochemical flow-cell, using as working electrodes
a Pt thin film deposited on a Ti substrate (Pt/Ti) prepared by the Pechini method and a pure platinum (Pt) foil. Using the
Pt/Ti electrodes better results for dye decolourisation were obtained under milder conditions than those used for pure Pt.
For the Pt electrode, colour removal of 93 % (λ = 493 nm) was obtained after 60 min, at 2.2 V vs. RHE, using 0.017 mol L−1 NaCl + 0.5 mol L−1 H2SO4 solution. For the Pt/Ti electrode there was better colour removal, 98%, than for the Pt electrode. Moreover, we used 0.017 mol L−1 NaCl solution and the applied potential was 1.8 V. Under this condition after 15 min of electrolysis, more than 80% of colour
was removed. The rate reaction constant, assuming a first order reaction, was 0.024 min−1 and 0.069 min−1, for Pt and Pt/Ti electrodes, respectively. 相似文献
16.
The application of zeolite Y-multiwalled carbon nanotube (MWCNT) nanocomposite modified glassy carbon electrode (zeolite Y-MWCNT/GCE)
in the electroanalysis of Cu2+ ion is presented. In order to bring out the unique advantage of the zeolite Y-MWCNT/GCE, experiments were carried out also
at graphite/GCE, MWCNT/GCE and zeolite Y-graphite/GCE. For the same surface area, the performance of zeolite Y-MWCNT/GCE was
superior to the other modified electrodes in terms of current sensitivity for Cu2+ ion. The combination of zeolite Y and MWCNT as a nanocomposite resulted in a good synergetic effect. The Cu+2 ion sensor exhibited a linear calibration range between 5 × 10−8 and 1 × 10−5 mol L−1 with a detection limit of 1.12 × 10−8 mol L−1 (0.72 ppb). 相似文献
17.
Weihua Guo Lin Xu Bingbing Xu Yanyan Yang Zhixia Sun Shuping Liu 《Journal of Applied Electrochemistry》2009,39(5):647-652
Keggin-type polyoxometalate (H4SiMo12O40) and carbon nanotubes (CNTs) coated by poly(allylamine hydrochloride) (PAH) were alternately deposited on glassy carbon (GC)
electrodes by an electrochemical growth method in acidic aqueous solution. The preparation of the film electrode was simple
and convenient. Thus-prepared multilayer films and the electrochemical behavior of the composite film modified electrode were
characterized by UV–vis spectroscopy and cyclic voltammetry. It was shown that the multilayer films are uniform and stable.
The resulting multilayer film modified electrode behaves as an electrochemical sensor because of its low overpotential for
the catalytic reduction of S2O8
2− and NO2
− in acidic aqueous solution. 相似文献
18.
A kind of mesoporous SiO2 was synthesized using cationic surfactant as the structure-directing template. After that, the resulting mesoporous SiO2 was used to modify the carbon paste electrode (CPE). The electrochemical behaviors of honokiol and magnolol were examined.
In pH 6.5 phosphate buffer, two well-shaped oxidation peaks at 0.31 and 0.44 V were observed at the mesoporous SiO2-modified CPE. Compared with the unmodified CPE, the mesoporous SiO2-modified CPE remarkably enhances the oxidation peak currents of honokiol and magnolol. This suggests that mesoporous SiO2 exhibits considerable surface enhancement effects to honokiol and magnolol. After optimizing the parameters such as pH value,
amount of mesoporous SiO2, and accumulation time, a sensitive and simple electrochemical method was proposed for the simultaneous determination of
honokiol and magnolol. As to honokiol, the calibration curve is from 2.0 to 100.0 μg L−1, and the limit of detection is 0.5 μg L−1 (1.8 × 10−9 mol L−1). For magnolol, the linear range is from 20.0 to 200.0 μg L−1, and the limit of detection is 10.0 μg L−1 (3.8 × 10−8 mol L−1). Finally, the newly proposed method was successfully employed to determine honokiol and magnolol in Chinese traditional
medicines. 相似文献
19.
Electrochemical simultaneous determination of nitrophenol isomers at nano-gold modified glassy carbon electrode 总被引:1,自引:1,他引:0
A novel method for simultaneous determination of nitrophenol isomers at nano-gold modified glassy carbon electrode has been
developed. The gold nanoparticles were directly electrodeposited onto the glassy carbon electrode via a constant potential
−0.2 V (vs. SCE) for 60 s from 0.1 mol L−1 KNO3 containing 0.4 g L−1 HAuCl4. The resulting electrode (nano-Au/GCE) was characterized with scanning electron microscopy (SEM). The electrochemistry response
of nitrophenol isomers at the nano-Au/GCE was studied. The result indicated that o-, m-, and p- nitrophenol are separated entirely at nano-Au/GCE, and a semi-derivative voltammetric technology was adopted to enhance
the determination sensitivity. This modified electrode could be applied to direct simultaneous voltammetric determination
of nitrophenol isomers in water samples without preseparation with higher sensitivity. 相似文献
20.
Pristine activated carbon (AcC) was oxidized by H2O2 under ultrasonic conditions. Compared with pristine AcC, the H2O2-oxidized AC possesses higher accumulation ability to trace levels of Cd2+. Based on this, a highly sensitive, simple and rapid electrochemical method was developed for the determination of Cd2+. In 0.01 mol L−1 HClO4 solution, Cd2+ was effectively accumulated at the surface of H2O2-oxidized AcC modified paste electrode, and then reduced to Cd under −1.10 V. During the following potential sweep from −1.10
to −0.50 V, reduced Cd was oxidized and a sensitive stripping peak appears at −0.77 V. The stripping peak current of Cd2+ changes linearly with concentration over the range 5.0 × 10−8 to 5.0 × 10−6 mol L−1. The limit of detection was found to be 3.0 × 10−8 mol L−1 for 2-min accumulation. Finally, this new sensing method was successfully used to detect Cd2+ in waste water samples. 相似文献