共查询到20条相似文献,搜索用时 15 毫秒
1.
Wensheng Huang Chunhai Yang Wanyun Qu Shenghui Zhang 《Russian Journal of Electrochemistry》2008,44(8):946-951
In this work, an electrochemical method for the determination of malachite green was developed on the basis of enhancement
effect of an anionic surfactant: sodium dodecyl benzene sulfonate. It is found that the oxidation peak current of malachite
green at carbon paste electrode significantly increases in the presence of low concentration of sodium dodecyl benzene sulfonate
in pH 6.5 phosphate buffer, suggesting that sodium dodecyl benzene sulfonate shows obvious enhancement effect for the determination
of malachite green. The experimental parameters, such as supporting electrolyte, kind of surfactant, concentration of sodium
dodecyl benzene sulfonate and accumulation time, were optimized, and then a sensitive and convenient electrochemical method
was proposed for the determination of malachite green. The oxidation peak current is proportional to the concentration of
malachite green over the range from 8.0 × 10−9 to 5.0 × 10−7 mol l−1, and the detection limit is 4.0 × 10−9 mol l−1 after 5 min of accumulation. Finally, this new method was successfully employed to detect malachite green in fish samples.
Published in Russian in Elektrokhimiya, 2008, Vol. 44, No. 8, pp. 1019–1024.
The text was submitted by the authors in English. 相似文献
2.
In pH 5.5, 0.1 mol l−1 HAc-NaAc buffer solution, trinitrophenol has been determined quantitatively with differential pulse voltammetry by detecting
its reduction peak currents at the glassy carbon electrode. The detection sensitivity was enhanced significantly by the addition
of the surfactant of cetyl pyridinium chloride, and the enhancement mechanism was also studied in detail. The linear calibration
range was 8.0 × 10−7 to 2.0 × 10−4 mol l−1, and the detection limit was established to be 1.9 × 10−7 mol l−1. This method has been applied to the determination of trinitrophenol in water sample, and the recovery was from 97.6 to 103.5%. 相似文献
3.
Xiaojiang Zheng Dazhai Zhou Dongshan Xiang Wensheng Huang Shaofang Lu 《Russian Journal of Electrochemistry》2009,45(10):1183-1187
A poly(L-cysteine) thin film was prepared onto electrode surface via electropolymerization. In pH 7.0 phosphate buffer, L-cysteine was oxidized during the cyclic potential sweep between −0.60 and 2.00 V, forming a thin film at the glassy carbon
electrode (GCE) surface. The electrochemical behaviors of ascorbic acid at the bare GCE and the poly(L-cysteine) film-coated GCE were investigated. The oxidation peak potential of ascorbic acid shifts to more negative potential
at the poly(L-cysteine) film-modified GCE. Moreover, the oxidation peak current significantly increases at the poly(L-cysteine) film-modified GCE. These phenomena indicate that poly(L-cysteine) film shows highly-efficient catalytic activity to the oxidation of ascorbic acid. Based on this, a sensitive and
simple electrochemical method was proposed for the determination of ascorbic acid. The oxidation peak current of ascorbic
acid is proportional to its concentration over the range from 1.0 × 10−6 to 5.0 × 10−4 mol l−1. The limit of detection is evaluated to be 4.0 × 10−7 mol l−1. 相似文献
4.
Xiao-Gang Wang Ya-Juan Fan Zhi-Xian Hao Li-Hua Gan 《Russian Journal of Electrochemistry》2010,46(12):1402-1407
In pH 5.0, 0.1 mol l−1 NaAc-HAc buffer solution, 2,4-dinitrophenol and 2,5-dinitrophenol exhibited sensitive and distinguishable voltammetric responses
at the glassy carbon electrode modified with poly-aspartic acid. By measuring the reduction peak currents of nitro groups
in different positions, dinitrophenol isomers have been determined simultaneously and quantitatively. The linear calibration
ranges were 1.1 × 10−6–6.0 × 10−4 mol l−1 for 2,4-dinitrophenol and 7.0 × 10−7–6.0 × 10−4 mol l−1 for 2,5-dinitrophenol, with detection limits of 2.7 × 10−7 and 1.1 × 10−7 mol l-1 respectively. This method has been applied to the detection of dinitrophenols in simulation water sample, and the
recovery was from 96.7 to 102.5%. 相似文献
5.
Jinyi Chen Guangzhong Yang Wanyi Li Jiashou Sun 《Russian Journal of Electrochemistry》2009,45(8):908-912
The virgin activated carbon (AC) was oxidized by 30% H2O2 under the ultrasonic condition for 6 h (denoted as AC-6). The electrochemical response of Pb2+ at the AC-6 modified paste electrode was investigated, suggesting that AC-6 shows much higher accumulation efficiency to
trace levels of Pb2+. Based on this, a sensitive and convenient electrochemical method was developed for the determination of Pb2+ utilizing the excellent properties of AC-6. In pH 3.6 HAc-NaAc buffer, Pb2+ was easily accumulate at the surface of AC-6 modified paste electrode, then reduced to Pb at −1.20 V. During the following
anodic sweep, the reduced Pb was oxidized and resulted in an oxidation stripping peak at −0.58 V. The stripping peak current
is proportional to the concentration of Pb2+ over the range from the 8.0 × 10−9 to 2.0 × 10−6 mol l−1, and the limit of detection is as low as 2.0 × 10−9 mol l−1. Finally, this newly-developed method was successfully employed to determine Pb2+ in water samples. 相似文献
6.
Chunhai Yang Shenghui Zhang Yingxuan Liu Wensheng Huang 《Frontiers of Chemistry in China》2008,3(3):353-358
A multi-wall carbon nanotubes (MWNTs)-Nafion film-coated glassy carbon electrode (GCE) was fabricated and the electrochemical
behavior of ofloxacin on the MWNTs-Nafion film-coated GCE were investigated by cyclic voltammetry (CV), linear sweep voltammetry
(LSV) and electrochemical impedance spectroscopy (EIS). The oxidation peak current of ofloxacin increased significantly on
the MWNTs-Nafion film modified GCE compared with that using a bare GCE. This nano-structured film electrode exhibited excellent
enhancement effects on the electrochemical oxidation of ofloxacin. A well-defined oxidation peak attributed to ofloxacin was
observed at 0.97 V and was applied to the determination of ofloxacin. The oxidation peak current was proportional to ofloxacin concentration
in the ranges 1.0 × 10−8 to 1.0 × 10−6 mol/L and 1.0 × 10−6 to 2.0 × 10−5 mol/L. A detection limit of 8.0 × 10−9 mol/L was obtained for 400 s accumulation at open circuit (S/N = 3). This method for the detection of ofloxacin in human
urine was satisfactory.
__________
Translated from Chinese Journal of Applied Chemistry, 2007, 24(5): 540–545 [译自: 应用化学] 相似文献
7.
Yan-Yan Yu Qing-Sheng Wu Xiao-Gang Wang Ya-Ping Ding 《Russian Journal of Electrochemistry》2009,45(2):170-174
The electrochemical behaviors of ferulic acid were investigated at the glassy carbon electrode modified with multi-walled
carbon nanotube. In pH 5.5, 0.1 mol l−1 HAc-NaAc buffer solution, ferulic acid exhibited a pair of stable and sensitive redox signals at the modified electrode.
The reaction mechanism was explored. Through the cyclic voltammetry, trace amount of ferulic acid was detected quantitatively.
In the range of 1 × 10−5 to 5 × 10−3 mol l−1, the oxidation peak currents of ferulic acid have a linear relationship to the concentrations, the limit of detection was
estimated to be 1 × 10−7 mol l−1 (S/N = 3). The influences of substrate, pH and interference of coexisting substances were investigated for response properties
of the electrode. Actual Xiao Yao Pill samples were analyzed and satisfactory results were obtained, which meant that the
method could be used to detect the trace amount of ferulic acid in medicament.
The article is published in the original.
Published in Elektrokhimiya in Russian, 2009, Vol. 45, No. 2, pp. 180–184. 相似文献
8.
An amperometric sensor for the determination of indole-3-acetic acid (IAA) based on the CeCl3-DHP film modified gold electrode was developed. CeCl3 was dissolved into water in the presence of dihexadecyl hydrogen phosphate (DHP). The IAA sensor was prepared via evaporating
solvent of the CeCl3-DHP dispersion on the gold electrode surface. The amperometric response of IAA on the CeCl3-DHP film modified gold electrode was investigated. The experimental results indicate that the passivation of the electrode
due to the adsorption of the oxidation product of IAA decreases significantly at the CeCl3-DHP film modified gold electrode, in contrast to that at the bare and the DHP modified gold electrode. The experimental parameters
were optimized and an electrochemical method for the determination of IAA was established. The oxidation peak current is linearly
with the concentration of IAA from 1 × 10−7 to 2 × 10−5 mol l−1 and the detection limit is 3 × 10−8 mol l−1. The relative standard deviation of eight measurements is 3.2% for 5 × 10−7 mol l−1 IAA. The IAA in plant leaves were extracted and determined by the IAA sensor. 相似文献
9.
A composite film modified glassy carbon electrode (GCE) fabricated with spinning coating of multiwalled carbon nano-tube (MWNT)
/1-butyl-3-methylimidazolium tetrafluoroborate/chitosan sol was developed for the electrochemical determination of 4-nitrophenol
(4-NP). An obvious reduction peak located at about −0.688 V was observed with voltammetric measurements in the potential range
from 0.200 V to −1.00 V. Compared with the bare GCE, the reduction peak potential shifted positively and the peak current
increased significantly. All experimental parameters for the determination of 4-NP were optimized. It was found that the reduction
peak current was proportional to 4-NP concentration in the range from 3.00 × 10−7 to 2.00 × 10−5 mol l−1 with the detect limitation of 1.00 × 10−7 mol l−1 (S/N = 3) after accumulation for 90 s. The proposed method was successfully applied for the determination of trace amounts
of 4-NP in lake water. 相似文献
10.
A poly(L-methionine) modified electrode, fabricated by electrochemical immobilization of the L-methionine on a glassy carbon
electrode, was used for simultaneous determination of dopamine and epinephrine through cyclic voltammetry. The electrochemical
properties of dopamine and epinephrine have been investigated. This sensor gave two separated cathodic peaks at −0.282 and
0.112 V for EP and DA, respectively. A linear response was obtained in the range of 5.0 × 10−7 to 1.0 × 10−4 mol l−1 for epinephrine, and 1.0 × 10−6 to 5.0 × 10−4 mol l−1 for dopamine. The detection limits were 3.6 × 10−7 mol l−1 and 4.2 × 10−7 mol l−1 for epinephrine and dopamine, respectively. This method was successfully applied for simultaneous determination of dopamine
and epinephrine in human urines.
The text was submitted by the authors in English. 相似文献
11.
A sensitive adsorptive anodic stripping procedure for the determination of trace zirconium at a carbon paste electrode (CPE)
has been developed. The method is based on adsorptive accumulation of the Zr(IV)-alizarin red S(ARS) complex onto the surface
of the CPE, followed by oxidation of adsorbed species. The optimal experimental conditions include the use of 0.10 mol · L−1 ammonium acetate buffer (pH 4.3), ARS, an accumulation potential of 0.20 V (versus SCE), an accumulation time of 2 min, a
scan rate of 200 mV · s−1 and a second-order derivative linear scan mode. The oxidation peak for the complex appears at 0.69 V. The peak current is
proportional to the concentration of Zr(IV) over the range of 1.0 × 10−9–2.0 × 10−7 mol · L−1, and the detection limit is 3 × 10−10 mol · L−1 for a 2 min adsorption time. The relative standard deviations (n = 8) for 5.0 × 10−8 and 5.0 × 10−9 mol · L−1 Zr(IV) are 3.3 and 4.8%, respectively. The proposed method was applied to the determination of zirconium in ore samples with
satisfactory results. 相似文献
12.
Yi Peng Junhui Xu Jia Zhao Bailin Hu Shengshui Hu 《Russian Journal of Electrochemistry》2008,44(2):206-212
The electrochemical response of phenol at acetylene black (AB)-dihexadecyl hydrogen phosphate (DHP) composite modified glassy
carbon electrode in the presence of cetyltrimethylammonium bromide (CTAB) was investigated. In this system, a sensitive oxidation
peak at 0.62 V (SCE) was obtained. The electrode process and the influence of CTAB on the oxidation of phenol were explored
by chronocoulometry and linear sweep voltammetry (LSV). Experimental conditions for the determination of phenol were optimized.
In the range of 5.0 × 10−7 to 1.2 × 10−5 M, the phenol concentration was linear with the oxidation peak current and the detection limit was found to be 1.0 × 10−7 M for 3 min accumulation. The method was applied for the determination of phenol in lake water and the results were satisfactory.
Published in Russian in Elektrokhimiya, 2008, Vol. 44, No. 2, pp. 222–229.
The text was submitted by the authors in English. 相似文献
13.
A new spectrofluorimetric method was developed for the determination of trace amounts of coenzyme A (CoA). In the presence
of periodic acid (H5IO6), CoA can remarkably enhance the fluorescence intensity of the Tb3+–ciprofloxacin (CIP) complex at 545 nm in a buffer solution at pH 5.4; the enhanced fluorescence intensity of the Tb3+ ion is proportional to the concentration of CoA. The optimal conditions for the determination of CoA were also investigated.
The linear range and the detection limit for the determination of CoA were 6.08 × 10−6–1.64 × 10−5 and 2.1 × 10−8 mol L−1, respectively. This method is simple, practical and relatively free of interference from coexisting substances, and can be
successfully applied to assess CoA in injection and biological samples. Moreover, the enhancement mechanism of the fluorescence
intensity of the CoA–Tb3+–CIP system in the presence of H5IO6 is also discussed. 相似文献
14.
Juliana Canto Duarte Rita de Cássia Silva Luz Flavio Santos Damos Adriano Bof de Oliveira Lauro Tatsuo Kubota 《Journal of Solid State Electrochemistry》2007,11(5):631-638
The electrocatalytical oxidation of hydrazine at low potential using tetracyanoquinodimethanide adsorbed on silica modified
with titanium oxide was investigated by cyclic voltammetry and amperometry. The modified electrode was prepared modifying
a carbon paste electrode employing lithium tetracyanoquinodimethanide adsorbed onto silica gel modified with titanium oxide.
This electrode showed an excellent catalytic activity and stability for hydrazine oxidation. With this modified electrode,
the oxidation potential of hydrazine was shifted toward less positive value, presenting a peak current much higher than those
observed on a bare GC electrode. The linear response range, sensitivity and detection limit were, respectively, 2 up to 100 μmol
l−1, 0.36 μA l μmol−1, and 0.60 μmol l−1. The repeatability of the modified electrode evaluated in term of relative standard deviation was 4.2% for 10 measurements
of 100 μmol l−1 hydrazine solution. The number of electrons involved in hydrazine oxidation (4), the heterogenous electron transfer rate
constant (1.08 × 103 mol−1 l s−1), and diffusion coefficient (5.9 × 10−6 cm2 s−1) were evaluated with a rotating disk electrode. 相似文献
15.
A multi-wall carbon nanotube (MWNT)/cetyl pyridine bromine (CPB) composite film modified glassy carbon electrode (GCE) was
developed for the electrochemical determination of hymecromone in phosphonate buffer. Electrochemical behaviour of hymecromone
at the composite film electrode was investigated with voltammetry. Compared with an irreversible oxidation of hymecromone
at the bare GCE, the oxidation peak current was enhanced greatly at the film electrode. Some parameters such as pH, scan rate,
accumulation potential and accumulation time were optimized. Under optimal conditions, an oxidation peak at 0.82 V was employed
to determine hymecromone electrochemically. A linearity between the oxidation peak current and the hymecromone concentration
was obtained in the range of 3.0 × 10−7 − 2.0 × 10−5 mol 1−1 with a detection limit of 8.0 × 10−8 mol 1−1. The proposed procedure was successfully applied to assay hymecromone in pharmaceutical formulation with satisfactory results.
The text was submitted by the authors in English. 相似文献
16.
《Fresenius' Journal of Analytical Chemistry》1992,344(1-2):34-38
Summary The anodic voltammetric behaviour of pentachlorophenol at a silica gel-modified carbon paste electrode in aqueous solution
is reported. Adsorption of the fungicide onto the electrode under open-circuit conditions is followed by application of either
differential or square wave voltammetry. The results obtained by differential pulse voltammetry at pH 2.9, with a modifier
concentration of 10% and accumulation times of 120 and 300 s, allowed the development of a method to determine pentachlorophenol
in the ranges of 1.0×10−6–1.0×10−5 and 1.0×10−7–1.0×10−6 mol l−1. The relative standard deviation is 2.6% for a concentration of 2.0×10−7 mol l−1, with a detection limit of 1.8×10−8 mol l−1 (5 ppb). The effect of other chlorophenols was studied. The results obtained by square wave voltammetry showed a behaviour
typical of an irreversible electron transfer. Amplitude, step height and frequency were optimised, taking into account the
resolution of the voltammetric response. No improvement in sensitivity was obtained with respect to DPV. Good results were
obtained by applying the proposed differential-pulse voltammetric method to the determination of pentachlorophenol in a commercial
fungicide. 相似文献
17.
A catalytic adsorptive stripping voltammetric method for the determination of copper(II) on a carbon paste electrode (PCE)
in an alizarin red S (ARS)-K2S2O8 system is proposed. In this method, copper(II) is effectively enriched by both the formation and adsorption of a copper(II)-ARS
complex on the PCE, and is determined by catalytic stripping voltammetry. The catalytic enhancement of the cathodic stripping
current of the Cu(II) in the complex results from a redox cycle consisting of electrochemical reduction of Cu(II) ion in the
complex and subsequent chemical oxidation of the Cu(II) reduction product by persulfate, which reduces the contamination of
the working electrode from Cu deposition and also improves analytical sensitivity. In Britton-Robinson buffer (pH 4.56±0.1)
containing 3.6×10−5 mol L−1 ARS and 1.6×10−3 mol L−1 K2S2O8, with 180 s of accumulation at −0.2 V, the second-order derivative peak current of the catalytic stripping wave was proportional
to the copper(II) concentration in the range of 8.0×10−10 to ∼3.0×10−8 mol L−1. The detection limit was 1.6×10−10 mol L−1. The proposed method was evaluated by analyzing copper in water and soil. 相似文献
18.
The polymerization of o-phenylenediamine (OPD) on l-tyrosine (Tyr) functionalized glassy carbon electrode (GCE) and its electro-catalytic oxidation towards ascorbic acid (AA)
had been studied in this report. l-Tyrosine was first covalently grafted on GCE surface via electrochemical oxidation, which was followed by the electrochemical
polymerization of OPD on the l-tyrosine functionalized GCE. Then, the poly(o-phenylenediamine)/l-tyrosine composite film modified GCE (POPD-Tyr/GCE) was obtained. X-ray photo-electron spectroscopy (XPS), field emission
scanning electron microscope (SEM), and electrochemical techniques have been used to characterize the grafting of l-tyrosine and the polymerization and morphology of OPD film on GCE surface. Due to the doping of the carboxylic functionalities
in l-tyrosine molecules, the POPD film showed good redox activity in neutral medium, and thus, the POPD-Tyr/GCE exhibited excellent
electrocatalytic response to AA in 0.1 mol l−1 phosphate buffer solution (PBS, pH 6.8). The anode peak potential of AA shifted from 0.58 V at GCE to 0.35 V at POPD-Tyr/GCE
with a greatly enhanced current response. A linear calibration graph was obtained over the AA concentration range of 2.5 × 10−4–1.5 × 10–3 mol l−1 with a correlation coefficient of 0.9998. The detection limit (3δ) for AA was 9.2 × 10−5 mol l−1. The modified electrode showed good stability and reproducibility and had been used for the determination of AA content in
vitamin C tablet with satisfactory results. 相似文献
19.
Yu-Jing Guo Jing-Hao Pan Xiao-Mei Li Fei Lu You-Qin Li 《Journal of inclusion phenomena and macrocyclic chemistry》2006,56(1-2):243-246
In this paper, a simple, rapid, sensitive and accurate electroanalytical method of Acid Blue 120 (AB120) has been established by polarography. In a supporting electrolyte of 0.01 mol l−1 Na2HPO4–KH2PO4 (pH 7.04) solution, a sensitive first derivative reduction peak (ip′) of AB120 was found by Linear Sweep Voltammetry (LSV). The peak potential is −820 mV (versus SCE). The peak current (ip′) is proportional to the concentration over the range 2.0 × 10−7–5.0 × 10−5 mol l−1 (r=0.9961–0.9991) and the limit of detection (LOD) is 1.0 × 10−7 mol l−1. The recovery of AB120 varied from 95.3 to 103.0% and the relative standard deviation (RSD) was 2.2% (n=8). The method has been expected to determination of wastewater in dye industry. In addition, the supramolecular system of AB120 with cyclodextrins has been studied. It can form 1:1 inclusion complex with six CDs. The inclusion constants were calculated and the inclusion ability of different kinds of CDs was compared. Furthermore, the inclusion mechanism was also preliminarily discussed, which provided some valuable information for further application of AB120 and CDs. 相似文献
20.
The voltammetric determination of 2-mercaptobenzimidazole (MBI) was studied by using a glassy carbon electrode (GCE) coated
with polymeric nickel and copper tetraaminophthalocyanine (poly-NiTAPc and poly-CuTAPc) membrane. The polymeric membrane decreases
the overpotential of oxidation of MBI by 136.2 and 115.0 mV and increases the oxidation peak current by about 3.4 and 3.3
times, while the reduction peak potential shifts positively by 113.0 and 84.1 mV and the peak current increases by about 10
and 7 times in 0.1 mol·l−1 phosphate buffer solution (PBS) at pH = 2.0 for poly-NiTAPc and poly-CuTAPc, respectively, compared to the unmodified GCE.
The results indicated that the developed electrode exhibited efficient electrocatalytic activity for MBI with relatively high
sensitivity, stability, and long life. The oxidation and reduction peak currents of MBI were linear to its concentrations
ranging from 8.0 × 10−5 to 1.0 × 10−3 mol·l−1 at poly-NiTAPc and from 2.0 × 10−5 to 1.0 × 10−3 mol·l−1 at poly-NiTAPc membranes modified electrodes, respectively, with a low limit of detection. 相似文献