共查询到20条相似文献,搜索用时 31 毫秒
1.
Chunya Li 《Mikrochimica acta》2007,157(1-2):21-26
Multi-wall carbon nanotubes (MWNT) were dispersed into water in the presence of dicetyl phosphate (DCP), and MWNT-DCP composite
film coated glassy carbon electrodes (GCE) were constructed. The electrochemical properties of 2-chlorophenol at a bare GCE
and MWNT-DCP modified GCE were compared. It was found that MWNT-DCP modified GCEs significantly enhance the oxidation peak
current of 2-chlorophenol and lowers its oxidation overpotential, suggesting great potential in the sensitive determination
of 2-chlorophenol. Finally, a sensitive and simple voltammetric method was developed for the determination of 2-chlorophenol.
The oxidation peak current increases linearly with the concentration in the range of 1.0 × 10−7–2.0 × 10−5 mol L−1, and the detection limit is 4.0 × 10−8 mol L−1 for 2 min accumulation. The method was successfully used to determine 2-chlorophenol in waste water samples. 相似文献
2.
A novel L-cysteine film modified electrode has been fabricated by means of an electrochemical oxidation procedure, and it
was successfully applied to the electrochemical determination of acetaminophen. This method utilizes the electrooxidation
of amines to their analogous cation radicals to form a chemically stable covalent linkage between the nitrogen atom of the
amine and edge plane sites at the glassy carbon electrode surface. The electrochemical behaviour of acetaminophen at the film
electrode was investigated in 0.1 mol L−1 phosphate buffer (pH 6.20). It was found that the redox peak current of acetaminophen was enhanced greatly on the film electrode.
Linearity between the oxidation peak current and the acetaminophen concentration was obtained in the range of 1.0 × 10−4–2.0 × 10−7 mol L−1 with a detection limit of 5.0 × 10−8 mol L−1. For seven parallel detections of 1.0 × 10−5 mol L−1 acetaminophen, the relative standard deviation (RSD) was 1.46%, suggesting that the film electrode has excellent reproducibility.
Application to the determination of acetaminophen in drug tablets and human urine demonstrated that the film electrode has
good stability and high sensitivity. 相似文献
3.
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
4.
We report a sensitive and convenient voltammetric method for the direct determination of 10-hydroxycamptothecin (HCPT). At
a multi-wall carbon nanotube (MWNT)-modified electrode, HCPT yields a very sensitive and well-shaped oxidation peak, which
can be used as analytical signal for HCPT determination. Compared with the poor electrochemical signal at the unmodified GCE,
the electrochemical response of HCPT at the MWNT-modified GCE was greatly improved, as confirmed by the significant peak current
enhancement. This result indicates that the MWNT-modified GCE has great potential in the sensitive determination of HCPT.
Based on this, a very sensitive and simple electrochemical method was proposed for HCPT determination after all the experimental
parameters were optimized. The newly-proposed method possesses very low detection limit (2 × 10−9 mol L−1) and wider linear range (from 1 × 10−8 to 4 × 10−6 mol L−1). Rapid and simple sample analysis is another advantage. Finally, this method was successfully demonstrated using HCPT drugs. 相似文献
5.
Qiong He Tian Gan Dongyun Zheng ShengShui Hu 《Journal of Solid State Electrochemistry》2010,14(6):1057-1064
Simple and sensitive electrochemical method for the determination of nitrite, based on a nano-alumina-modified glassy carbon
electrode (GCE), is described. Nitrite yields a well-defined oxidation peak whose potential is 0.74 V at the nano-alumina-coated
GCE in 0.1 mol L−1 phosphate buffer (pH 5.0). Compared with bare GCE, the nano-alumina-modified GCE has evident catalytic effect towards the
oxidation of nitrite, and its peak current can be significantly enhanced. Some of the experimental parameters were optimized
for the determination of nitrite. The oxidation peak current was proportional to nitrite concentration in the range of 5.0 × 10−8–1.1 × 10−3 mol L−1, and a detection limit of 1.0 × 10−8 mol L−1 was obtained. This method has been successfully used to the determination of nitrite in sausage sample. Furthermore, results
obtained by the method have been compared with spectrophotometric method. 相似文献
6.
Lin Cui Lifang Li Shiyun Ai Huanshun Yin Peng Ju Tao Liu 《Journal of Solid State Electrochemistry》2011,15(6):1253-1261
Guanosine-5′-monophosphate (GMP) was investigated the electrochemical behaviors based on solid-phase extractionon (SPE) at
Cu-Mg-Al hydrotalcite-like compound (HTLC) modified glass carbon electrode. Cu-Mg-Al hydrotalcite-like compound (HTLC) was
proved as a new sorbent for SPE of GMP, which showed an irreversible adsorption oxidation process on the HTLC/GCE with the
oxidation peak potential located at 1.15 V (vs. SCE) in a pH 5.0 acetate buffer solution. Influencing factors of the electrochemical
behavior of GMP on the HLTC/GCE were optimized and kinetic parameters were calculated. Under the optimal conditions, with
differential pulse voltammetry (DPV), a linear relationship was obtained between the oxidation peak current and the GMP concentration
in the range from 1.0 × 10− 6 to 8.0 × 10−4 mol L−1 with the detection limit as 5.0 × 10−7 mol L−1 (signal-to-noise ratio of 3). The modified electrode surface has very good reproducibility and stability. 相似文献
7.
Covalent modification of a glassy carbon electrode with penicillamine for simultaneous determination of hydroquinone and catechol 总被引:1,自引:0,他引:1
Liang Wang Peng Fei Huang Jun Yue Bai Hong Jing Wang Li Ying Zhang Yu Qing Zhao 《Mikrochimica acta》2007,158(1-2):151-157
A simple and highly selective electrochemical method has been developed for the simultaneous determination of hydroquinone
(HQ) and catechol (CC) at a glassy carbon electrode covalently modified with penicillamine (Pen). The electrode is used for
the simultaneous electrochemical determination of HQ and CC and shows an excellent electrocatalytical effect on the oxidation
of HQ and CC upon cyclic voltammetry in acetate buffer solution of pH 5.0. In differential pulse voltammetric measurements,
the modified electrode was able to separate the oxidation peak potentials of HQ and CC present in binary mixtures by about
103 mV although the bare electrode gave a single broad response. The determination limit of HQ in the presence of 0.1 mmol L−1 CC was 1.0 × 10−6 mol L−1, and the determination limit of CC in the presence of 0.1 mmol L−1 HQ was 6.0 × 10−7 mol L−1. The method was applied to the simultaneous determination of HQ and CC in a water sample. It is simple and highly selective. 相似文献
8.
Jun Yue Bai Liang Wang Hong Jing Wang Peng Fei Huang Yu Qing Zhao Sheng Di Fan 《Mikrochimica acta》2006,156(3-4):321-326
The electrochemical behavior of epinephrine (EP) at a mercaptoacetic acid (MAA) self-assembled monolayer modified gold electrode
was studied. The MAA/Au electrode is demonstrated to promote the electrochemical response of epinephrine by cyclic voltammetry.
The possible reaction mechanism is also discussed. The diffusion coefficient D of EP is 6.85 × 10−6 cm2 s−1. In 0.1 mol L−1 phosphate buffer (pH 7.20), a sensitive oxidation peak was observed at 0.177 V, and the peak current is proportional to the
concentration of EP in the range of 1.0 × 10−5–2.0 × 10−4 mol L−1 and 1.0 × 10−7–1.0 × 10−6 mol L−1. The detection limit is 5 × 10−8 mol L−1. The modified electrode is highly stable and can be applied to the determination of EP in practical injection samples. The
method is simple, quick, sensitive and accurate. 相似文献
9.
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
10.
A self-assembled electrode with a meso-2,3-dimercaptosuccinic acid (DMSA) monolayer has been characterized by electrochemical
quartz crystal microbalance and complex impedance analysis, surface enhanced Raman spectroscopy and cyclic voltammetry. The
self-assembled electrode was used for the simultaneous electrochemical detection of epinephrine (EP) and uric acid (UA) in
phosphate buffer of pH 7.7. The simultaneous oxidation of EP and UA was performed by cyclic voltammetry (CV) and differential
pulse voltammetry (DPV), and the signals for each method were well separated with a potential difference of over 330 mV and
without interference by each other. The detection limit of EP is 5.4 × 10−8 mol L−1 by CV and 5.3 × 10−8 mol L−1 by DPV and that of UA is 8.4 × 10−8 mol L−1 by CV and 4.2 × 10−8 mol L−1 by DPV. The DMSA self-assembled electrode can be applied to the simultaneous determination of EP and UA. 相似文献
11.
A voltammetric sensor for the determination of parathion has been developed based on the use of a poly(carmine) film electrode.
The reduction of parathion at the poly(carmine) modified glassy carbon electrode (GCE) is studied by cyclic voltammetry (CV)
and linear scan voltammetry (LSV). Parathion yields a well-defined reduction peak at a potential of −0.595 V on the poly(carmine)
modified GCE in pH 6.0 phosphate buffer solution (PBS). Compared with that on a bare GCE, the reduction peak current of parathion
is significantly enhanced. All the experimental parameters are optimized for the determination of parathion. The reduction
peak current is linear with the parathion concentration in the range of 5.0 × 10−8 to 1.0 × 10−5 mol L−1, and the detection limit is 1.0 × 10−8 mol L−1. 相似文献
12.
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
13.
The fabrication and electrochemical characteristics of a penicillamine (PCA) self-assembled monolayer modified gold electrode
were investigated. The electrode can enhance the electrochemical response of uric acid (UA), and the electrochemical reaction
of UA on the PCA electrode has been studied by cyclic voltammetry and differential pulse voltammetry. Some electrochemical
parameters, such as diffusion coefficient, standard rate constant, electron transfer coefficient and proton transfer number
have been determined for the electrochemical behavior on the PCA self-assembled monolayer electrode. The electrode reaction
of UA is an irreversible process, which is controlled by the diffusion of UA with two electrons and two protons transfer at
the PCA/Au electrode. In phosphate buffer (pH 5.0), the peak current is proportional to the concentration of UA in the range
of 6.0 × 10−5–7.0 × 10−4 mol L−1 and 2.0 × 10−5–7.0 × 10−4 mol L−1 for the cyclic voltammetry and differential pulse voltammetry methods with the detection limits of 5.0 × 10−6 and 3.0 × 10−6 mol L−1, respectively. The method can be applied to determine UA concentration in real samples. 相似文献
14.
Gongjun Yang Xilong Qu Ming Shen Chengyin Wang Qishu Qu Xiaoya Hu 《Mikrochimica acta》2008,160(1-2):275-281
Poly(phenol red) (denoted as PPR) films were electrochemically synthesized on the surface of a glassy carbon electrode (GCE)
by cyclic voltammetry to obtain a chemically modified electrode (denoted as PPR-GCE). The growth mechanism of PPR films was
studied by attenuated total reflection spectroscopy. This PPR-GCE was used to develop a novel and reliable method for the
determination of trace Pb2+ by anodic stripping differential pulse voltammetry. At optimum conditions, the anodic peak exhibits a good linear concentration
dependence in the range from 5.0 × 10−9 to 5.0 × 10−7 mol L−1 (r = 0.9989). The detection limit is 2.0 × 10−9 mol L−1 (S/N = 3). The method was employed to determine trace levels of Pb2+ in industrial waste water samples.
Correspondence: Gongjun Yang, Ming Shen, College of Chemistry and Chemical Engineering, Yangzhou University, Yangzhou 225002,
P.R. China 相似文献
15.
The electrooxidative behaviour and determination of quetiapine (QTP), a dibenzothiazepine derivative and antipsychotic agent,
on a glassy carbon disc electrode was investigated using cyclic (CV), linear sweep (LSV), differential pulse (DPV) and Osteryoung
square wave voltammetry (OSWV). Fully validated DP and SW voltammetric procedures are described for the determination of QTP.
QTP in pH 3.5 acetate buffer solution presents a well-defined anodic response, studied by the proposed methods. This main
response was due to the irreversible, diffusion-controlled, one-electron and one-proton oxidation of the aliphatic nitrogen
of the piperazine ring. Under optimal conditions, a detection limit of 4.0 × 10−8 mol L−1 for DPV and 1.33 × 10−7 mol L−1 for OSWV, and a linear calibration graph in the range from 4.0 × 10−6 to 2.0 × 10−4 mol L−1 were obtained for both methods. The procedure was successfully applied to the determination of the drug in tablets, human
serum and human urine with good recoveries. The detection limits were 6.20 × 10−7 mol L−1 and 5.92 × 10−7 mol L−1 in human serum and 1.44 × 10−7 mol L−1 and 1.31 × 10−6 mol L−1 in human urine, for the DPV and OSWV method, respectively. 相似文献
16.
Gang Li Suling Yang Lingbo Qu Ran Yang Jianjun Li 《Journal of Solid State Electrochemistry》2011,15(1):161-166
A Nafion/multi-wall carbon nanotubes (MWNT) composite film-modified electrode was fabricated. The modified electrode showed
excellent electrocatalytic activity toward ascorbic acid (AA) and uric acid (UA) in 0.1-mol L−1 NaCl medium (pH 6.5). Compared to the bare electrode that only displayed a broad and overlapped oxidation peak, the Nafion/MWNT
film-modified electrode not only remarkably enhanced the anodic peak currents of AA and UA but also avoided the overlapping
of the anodic peaks of AA and UA with a 320-mV separation of both peaks. Under the optimized conditions, the peak currents
of AA and UA were proportional to their concentration at the ranges of 8.0 × 10−5 to 6.0 × 10−3 mol L−1 and 6.0 × 10−7 to 8.0 × 10−5 mol L−1, respectively. The proposed method was used for the detection of AA and UA in real samples with satisfactory results. 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.
A 3-amino-5-mercapto-1,2,4-triazole (TA) self-assembled monolayer-modified gold electrode (TA SAM/Au) is characterized by
X-ray photoelectron spectroscopy, A.C. impedance, cyclic voltammetry, chronoamperometry and chronocoulometry. The TA SAM/Au
exhibited good promotion of the electrochemical oxidation of dopamine. Some electrochemical parameters of dopamine such as
electron transfer number, exchange current density, standard heterogeneous rate constant, diffusion coefficient, etc., were
measured by different electrochemical methods. The peak currents of dopamine were linearly dependent on its concentration
in the range of 1.5 × 10−6–1.0 × 10−4 mol L−1, with a detection limit of 5.0 × 10−7 mol L−1. The oxidative peak potentials of dopamine and ascorbic acid were well separated at about 190 ± 10 mV in pH 2.0 BR buffers
at TA SAM/Au, the oxidation peak current increases approximately linearly with increasing concentration of both dopamine and
ascorbic acid in the concentration range of 9.98 × 10−6–4.54 × 10−4 mol L−1. It can be used for simultaneous determination of dopamine and ascorbic acid. 相似文献
19.
Single-wall carbon nano-tubes were used to modify the surface of a glassy carbon electrode (GC) and applied in the determination
of folic acid with voltammetry. The experiments demonstrated that the presence of a carbon nano-tube film on the electrode
greatly increased the reduction peak current of folic acid. Cyclic voltammetry (CV) and linear sweep voltammetry (LSV) were
used in a comparative investigation of the electrochemical reduction of folic acid with the film electrode. Effects of pH
on the peak current and the peak potential were studied in the pH range of 4.0–8.0 with Britton-Robinson buffer solution.
The reduction peak current was found to be linearly related to folic acid concentration over the range of 1 × 10−8 to 1 × 10−4 mol L−1 with a detection limit of 1 × 10−9 mol L−1 after 5 min accumulation. The film electrode provides an efficient way for eliminating interferences from some inorganic
and organic species in the solution. The high sensitivity, selectivity and stability of the film electrode demonstrate its
practical application from a simple and rapid determination of folic acid in tablets. 相似文献
20.
Lei Zhang 《Mikrochimica acta》2008,161(1-2):191-200
A covalently modified glassy carbon electrode with cysteine has been fabricated via an electrochemical oxidation procedure
and was applied to induce the electrochemical differentiation between dopamine (DA) and ascorbic acid (AA). Based on the electrostatic
interactions between the negatively charged groups on the electrode surface and DA and AA, the modified electrode enhanced
the oxidation of DA, reducing the overpotential by 180 mV, and hindered the oxidation of AA, shifting the oxidation potential
positively by 170 mV. The peak current for DA at the modified electrode was greatly enhanced and that for AA was significantly
decreased, which allows the determination of DA in the presence of AA. The differential pulse peak current was linearly dependent
on DA concentration over the range of 5 × 10−6–2 × 10−4 mol L−1. The detection limit was 1.8 × 10−6 mol L−1. The selectivity and sensitivity for dopamine is due to charge discrimination and analyte accumulation. The modified electrode
has been applied to the determination of DA in the presence of AA.
Correspondence: L. Zhang, Department of Chemistry, College of Life and Environmental Science, Shanghai Normal University,
Guilin Rd 100, Shanghai 200234, P.R. China 相似文献