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1.
The sonochemically facilitated, mercury free detection of Pb2+ at a copper electrode has been investigated as a means of simplifying the quantification of this important analyte and to minimise the interference of copper ion. The procedure relies upon maximising the formation of Pb-Cu intermetallic compounds leading to the emergence of a single, easily quantifiable stripping signal. Linear responses to Pb2+ were obtained with a sensitivity comparable to that obtained at a bare glassy carbon electrode. Interference from Cu2+, Zn2+ and Cd2+ was assessed on the copper electrode with no appreciable change in the Pb2+ voltammetric profile observed. In contrast, bare glassy carbon showed a significant change in Pb2+ voltammetric profile as Cu2+ was added, due to the formation of intermetallic species.  相似文献   

2.
Hydrogen peroxide in pickling baths for copper and copper alloys can be determined by linear sweep voltammetry with a glassy carbon electrode. The oxidation mechanism changes around 0.15 M H2O2. Catalytic decomposition was found to be much smaller at glassy carbon electrodes than at platinum electrodes. An almost linear calibration curve was obtained up to 60 mM H2O2. Interferences from Cu2+, Zn2+, Ni2+, Al3+, Fe3+ and Pb2+ as well as from the stabilizers were small. All measurements were made in sulphuric acid solutions.  相似文献   

3.
《Analytical letters》2012,45(14):2327-2343
Abstract

A novel approach for the voltammetric determination of Pb2+, Cu2+, and Hg2+ in the presence of macromolecule contaminants was developed. An Au nanoparticles array was directly electrodeposited onto the gold electrode surface followed by a further modification of a mercaptoethanesulfonate (MES) monolayer. Square wave stripping voltammetry (SWSV) of Pb2+, Cu2+, and Hg2+ was performed on the doubly modified electrode. The electrodeposited gold nanoparticles provided a significantly improved sensitivity. Simultaneously, the MES monolayer efficiently prevented the macromolecules accessing the electrode surface. Compared with the bare gold electrode, the doubly modified electrode has the ability to detect metal ions in the presence of macromolecule contaminants, even when their concentration reach 100 ppm. Under the optimal conditions, the detection limits of 0.16, 0.15, and 0.14 ppb for Pb2+, Cu2+, and Hg2+ were obtained, respectively. The calibration graphs were linear in the concentration range of 1–100 ppb. The results of the analysis of a real metallurgy wastewater sample were reported. The electrode system has a great potential for the direct determination of trace metals in the complex environment and biological samples.  相似文献   

4.
Lu J  He X  Zeng X  Wan Q  Zhang Z 《Talanta》2003,59(3):553-560
A novel calix[4]arene derivative containing benzothiazole group was coated on glassy carbon electrode (GCE) and then applied to the recognition of mercury ion. Cyclic and square wave voltammetric results showed that the modified electrode selectively recognizes Hg2+ ion in aqueous media. A new anodic stripping peak at −0.3 V (vs. Ag/Ag+) can be obtained by scanning the potential from −0.6 to 0.6 V, and the peak currents are proportional to the Hg2+ concentration. The modified electrode in a 0.1 M H2SO4+0.01 M NaCl solution shows linear voltammetric response in the range of 25-300 μg l−1 and detection limit of 5 μg l−1 (ca. 2.5×10−8 M). This modified GCE does not present any significant interference from alkali, alkaline and transition metal ions except for Pb2+, Ag+ and Cu2+ ions. Only 500, 50 and 100-fold molar excess of Pb2+, Ag+ and Cu2+ ions, respectively, can lead to voltammetric response comparable with that of Hg2+. The proposed method was successfully applied to determine mercury in natural water.  相似文献   

5.
We obtained a gold nanomaterial/graphene oxide-modified glassy carbon electrode and characterized it using transmission electron microscope, scanning electron microscope, cyclic voltammetry (CV), and X-ray photoelectron spectroscopy techniques. A response of the electrode using square wave anodic stripping voltammetry for Pb2+, Cu2+, and Hg2+ was found linear in the range from 1 × 10–7 to 1 × 10–11 M. The detection limits of Pb2+, Cu2+ and Hg2+ were 0.14, 0.5 and 1.2 pM, respectively. The method was applied to the simultaneous determination of Pb2+, Cu2+ and Hg2+ in seawater samples from a coastal region of Anatolia, and the results corresponded well with the values obtained by inductively coupled plasma-optical emission spectroscopy.  相似文献   

6.
Copper complex dye (C.I. Direct Blue 200) film modified electrodes have been prepared by multiple scan cyclic voltammetry. The effect of solution pH and nature of electrode material on film formation was investigated. The optimum pH for copper complex film formation on glassy carbon was found to be 1.5. The mechanism of film formation on ITO seems to be similar to that on GC surface but completely different mechanism followed with gold electrode. Cyclic voltammetric features of our modified electrodes are in consistent with a surface‐confined redox process. The voltammetric response of modified electrode was found to be depending on pH of the contacting solution. UV‐visible spectra show that the nature of copper complex dye is identical in both solution phase and after forming film on electrode. The electrocatalytic behavior of copper complex dye film modified electrode towards oxidation of dopamine, ascorbic acid and reduction of SO52? was investigated. The oxidation of dopamine and ascorbic acid occurred at less positive potential on film electrode compared to bare glassy carbon electrode. Feasibility of utilizing our modified electrode in analytical estimation of dopamine, ascorbic acid was also demonstrated.  相似文献   

7.
The anodic stripping peak current of lead on the glassy carbon electrode surface was greatly increased in the presence of high concentration of copper ion. The effects of supporting electrolyte, concentration of Cu2+, accumulation potential and accumulation time were studied on the stripping peak current of Pb2+. As a result, a sensitive, simple and rapid electrochemical method was developed for the detection of lead. In 0.01 M HNO3 solution containing 800 g,g L?1 Cu2+, the stripping peak current of Pb2+ increases linearly with its concentration over the range from 2 to 100 μg L?1. The detection limit is 1 μg L?1 after 4-min accumulation at ?0.8 V. It was used to detect the concentration of lead in blood samples, and the results consisted with the values that obtained by atomic absorption spectrometry.  相似文献   

8.
A new glassy carbon electrode modified with novel calix[4]‐arene derivative was prepared and then applied to the selective recognition of lead ion in aqueous media by cyclic and square wave voltammetry. A new anodic stripping peak at ? 0.92 V (vs. Ag/Ag+) in square wave voltammogram can be obtained by scanning the potential from ? 1.5 to ? 0.6 V, of which the peak current is proportional to the concentration of Pb2+. The modified electrode in 0.1 mol/L HNO3 solution showed a linear voltammetric response in the range of 2.0 × 10–8–1.0 × 10–6 mol/L and a detection limit of 6.1 × 10–9 mol/L. In the modified glassy carbon electrode no significant interference occurred from alkali, alkaline and transition metal ions except Hg2+, Ag+ and Cu2+ ions, which can be eliminated by the addition of KSCN. The proposed method was successfully applied to determine lead in aqueous samples.  相似文献   

9.
Carbon modified by the reduction of aromatic diazonium derivatives was first used as electrode for the electrochemical stripping analysis of heavy metals. As a model, the glassy carbon electrode was modified with benzoic acid by electrochemical reduction of diazobenzoic acid, and the resulting modified electrodes were used for determination of Cd2+ and Pb2+. The anodic peak currents of cadmium and lead at the benzoic acid-modified glassy carbon electrode are 7.2 and 6 times of that at the bare glassy carbon electrode. A linear response was observed for Pb2+ and Cd2+ in the range of 0.5–50 μg/l. The detection limits are 0.20 μg/l for Pb2+ and 0.13 μg/l for Cd2+. The relative standard deviations for six consecutive measurements of 50 μg/l Cd2+ and 50 μg/l Pb2+ are 0.82% and 3.02%, respectively. Applicability of the sensor to the determination of Cd2+ and Pb2+ in sewerage samples was demonstrated.  相似文献   

10.
We herein report a mercury‐free approach for the sensitive determination of trace Pb2+ in seawater using differential pulse stripping voltammetric (DPSV) method with a novel columnar glassy carbon electrode (CGCE). Compared with the conventional disk glassy carbon electrode with the same diameter, it has much larger electrochemical area (0.627 ± 0.003 cm2). The CGCE shows good accumulation ability and consequently acceptable behavior which makes it suitable as a working electrode in the DPSV determination of Pb2+ with the great advantage of the avoidance of harmful mercury. Using acidified artificial seawater as supporting electrolyte, there was a good linear relationship between the peak currents and the concentration of Pb2+ in the range of 0.6~140.0 μg L‐1 with a detection limit of 0.3 μg/L (S/N = 3) when the accumulation time was 300 s. The method was employed to determine trace levels of Pb2+ in real seawater samples successfully.  相似文献   

11.
A 2,2′‐azinobis (3‐ethylbenzothiazoline‐6‐sulfonate) diammonium salt (ABTS)‐multiwalled carbon nanotubes (MWCNTs) nanocomposite/Bi film modified glassy carbon (GC) electrode was constructed for the differential pulse stripping voltammetric determination of trace Pb2+ and Cd2+. This electrode was more sensitive than ABTS‐free Bi/GC and Bi/MWCNTs/GC electrodes. Linear responses were obtained in the range from 0.5 to 35 μg L?1 for Cd2+ and 0.2 to 50 μg L?1 Pb(II), with detection limits of 0.2 μg L?1 for Cd2+ and 0.1 μg L?1 for Pb2+, respectively. This sensor was applied to the simultaneous detection of Cd2+ and Pb2+ in water samples with satisfactory recovery.  相似文献   

12.
《Electroanalysis》2003,15(2):121-125
This work describes the behavior of copper solid amalgam electrodes (CuSAE). The applied potential range has been compared with that of the silver solid amalgam electrode (AgSAE) and the hanging mercury drop electrode (HMDE). In 0.05 M tetraborate buffer the applicable potential range of CuSAE is+0.945 V to ?1.75 V excluding ?0.2 V to ?0.5 V, where the anodic oxidation of copper occurs. CuSAE does not need other than electrochemical pre‐treatment, which has been documented by the evaluated repeatability of eleven voltammetric curves of Cd2+ (0.1 ppm), Pb2+ (0.1 ppm) and Mn2+ (0.5 ppm). The obtained results showed that CuSAE could substitute the solid copper, amalgamed copper or liquid copper amalgam electrodes, and can be applied for the study of systems needing an addition of Cu2+ ions into the measured solution.  相似文献   

13.
A glassy carbon electrode was modified with gold hierarchical dendrites (Au HDs) by one-step electrodeposition in the presence of cytosine, which plays an important role in the formation of the Au HDs. This approach is simple, fast, feasible, controllable, without any seed, template, or surfactant. The modified electrodes were used for the simultaneous determination of Pb2+ and Cu2+ by square wave stripping voltammetry. The peak currents show good linear relationship with concentrations of Pb2+ and Cu2+ in the range of 5.0 to 15.0 μM. The recoveries of the spiked water samples are in the range of 94.0 %–107.4 % for Pb2+ and Cu2+, and their relative standard deviation are in the range of 2.7 %–4.3 % for Pb2+ and Cu2+, respectively (n?=?3).
Figure
Well-defined Au hierarchical dendrites (HDs) modified electrodes were prepared by a simple, fast, feasible and controllable electrochemical route. The modified electrode was developed for the simultaneous and sensitive detection of Pb2+ and Cu2+ by square wave stripping voltammetry.  相似文献   

14.
The Cu (II) imprinted polymer glassy carbon electrode (GCE/Cu-IP) was prepared by electropolymerization of pyrrole at GCE in the presence of methyl red as a dopant and then imprinting by Cu2+ ions. This electrode was applied for potentiometric and voltammetric detection of Cu2+ ion. The potentiometric response of the electrode was linear within the Cu2+ concentration range of 3.9 × 10?6 to 5.0 × 10?2 M with a near-Nernstian slope of 29.0 mV decade?1 and a detection limit of 5.0 × 10?7 M. The electrode was also used for preconcentration anodic stripping voltammetry and results exhibited that peak currents for the incorporated copper species were dependent on the metal ion concentration in the range of 1.0 × 10?8 to 1.0 × 10?3 M and detection limit was 6.5 × 10?9 M. Also the selectivity of the prepared electrode was investigated. The imprinted polymer electrode was used for the successful assay of copper in two standard reference material samples.  相似文献   

15.
A sensitive voltammetric method for detection of trace heavy metal ions using chemically modified carbon nanotubes (CNTs) electrode surfaces is described. The CNTs were covalently modified with cysteine prior to casting on electrode surfaces. Cysteine is an amino acid with high affinities towards some heavy metals. In this assay, heavy metals ions accumulated on the cysteine‐modified CNT electrode surfaces prior to being subjected to differential pulse anodic stripping voltammetry analysis. The resulting peak currents were linearly related to the concentrations of the metal ions. The method was optimized with respect to accumulation time, reduction time and reduction potential. The detection limits were found to be 1 ppb and 15 ppb for Pb2+ and Cu2+ respectively. The technique was used for the detection of Pb2+ and Cu2+ in spiked lake water. The average recoveries of Pb2+ and Cu2+ were 96.2% and 94.5% with relative standard deviations of 8.43% and 7.53% respectively. The potential for simultaneous detection of heavy metal ions by the modified CNTs was also demonstrated.  相似文献   

16.
Using the method of cyclic voltammetry, the electrode process of Ni2+, Pb2+, Cu2+ and pyrocatechin on a poly(o-aminophenol) (PoAP) modified glassy carbon electrode (GCE) was investigated. The PoAP polymer was found to affect the redox process of copper and pyrocatechin. The use of polymer of different thicknesses showed that the obtained film has a dense, nonporous structure. The redox process of the examined substances may be considered as proceeding on the polymer surface. The PoAP polymer obtained in the described conditions takes part in charge transfer.   相似文献   

17.
徐琴  刘妮娜  朱俊杰 《中国化学》2005,23(11):1510-1514
A composite material of nitric acid oxidized multiwalled carbon nanotube (MWNT) and Nation was prepared. Such composite was modified on a glassy carbon electrode to determine trace of lead by differential pulsed voltammetry. In pH=6.47 NaNO3 solution, Pb^2+ ions were accumulated on the modified electrode at -0.4 V. Compared with a bare and a Nation film coated electrode, the composite coated GC electrode can reduce the accumulating potential and eliminate the toxic character of mercury. The calibration plots were linear at low concentration of 5.0× 10^-9-2.0× 10^-8 mol/L and high concentration of 2.5× 10^-8-5.0× 10^-6 mol/L. The performances characteristics indicate that the electrode can be used to determine trace Pb^2+ ions.  相似文献   

18.
《Electroanalysis》2006,18(5):485-492
A novel method for the fabrication of carbon nanotubes/poly(1,2‐diaminobenzene) nanoporous composite based electrode was proposed. By multipulse potentiostatic electropolymerization, the multi‐walled carbon nanotubes (MWNTs) and poly(1,2‐diaminobenzene) were deposited simultaneously on the electrode surface. Compared with the composite prepared by the traditional potentiodynamic method, the composite synthesized by multipulse potentiostatic method has a unique nanoporous structure, exhibits excellent conductivity and better environmental stability. The surface of the resulting electrode was characterized with scanning electron microscopy (SEM), cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The nanoporous composite film modified glassy carbon electrode was also used successfully for the simultaneously voltammetric determination of trace level of Cd2+ and Cu2+ at first‐time. Under the optimal conditions, the determination limits of 0.25 and 0.33 ppb for Cd2+ and Cu2+ were obtained, respectively. The calibration graphs were linear in the concentration range of 5–100 ppb. The electrode system provides an excellent platform for ultra sensitive electrochemical sensors for chemical and biological sensing.  相似文献   

19.
《Electroanalysis》2017,29(11):2572-2578
We report in this work, a new method for the determination of captopril by differential pulse voltammetry using a glassy carbon electrode modified with a copper metal‐organic framework (H‐Kust‐1 or Cu3(BTC)2 or Cu‐BTC), immobilized on the surface by a copolymer of acrylamide and sodium acrylate. This compound is detected by the formation of a copper(II)‐captopril complex that is observed in an oxidation potential at ca. +0.28 V vs . Ag/AgCl. A linear dynamic range is obtained for a captopril concentration of 0.5 μM to 7.0 μM and the voltammetric response is highly reproducible within 3.52 % error. The sensitivity of 9.71±0.37 nA μM−1 and the limit of detection of 0.20±0.01 μM make this methodology highly applicable for practical applications. The determination of captopril in a commercial pharmaceutical sample showed a recovery of 93.3 %.  相似文献   

20.
The electrochemical behavior of p‐tert‐butyl‐sulfonylcalix[4]arene (SCA) has been investigated by cyclic voltammetry. The results show that there is an irreversible electrochemical oxidative wave when the potential ranges from 0.9 to 1.9 V versus saturated calomel electrode (SCE) in CH2Cl2 at a glassy carbon electrode. The kinetic parameters of the andic wave, such as α,n, ks, D and the diffusion activation energy (Ed), were discussed. In addition, the interaction of SCA with metal ions at the water‐air interface was also discussed by Langmuir‐Blodgett (LB) techniques. The results confirm that the selectivity of SCA as ligand for Pb2+ in monomolecular film is very high by complexation action, which provide the foundation that LB film of SCA modified glassy carbon electrode (GCE) as voltammetric sensor to detect trace amounts of Pb2+.  相似文献   

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