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1.
Poobalasingam Abiman Gregory G. Wildgoose Alison Crossley Richard G. Compton 《Electroanalysis》2009,21(8):897-903
The adsorption behavior of model toxic metal cations namely Cd(II) and Hg(II) on carbon surfaces chemically modified by glutathione was investigated as a function of the concentration of Cd2+ and Hg2+ ions, time and the amount of modified carbon used. Square wave and linear sweep anodic stripping voltammetry was used to monitor the uptake of Cd(II) and Hg(II) ions respectively. Kinetic and adsorption isotherm studies reveal that both Cd(II) and Hg(II) ions undergo similar large adsorption with the modified glutathione carbon material (Glu‐carbon). 相似文献
2.
Voltammetric studies of rabbit liver metallothioneins (MTs, containing both Zn and Cd ions) and Zn7‐MT were carried out at Nafion‐coated mercury film electrodes (NCMFEs). The accumulation of MT molecules into the NCMFEs enhances the voltammetric signals and the electrostatic interaction between the Nafion membrane and MT facilitates facile electron transfer reactions. Two well‐defined redox waves, with reduction potential (Epc) values at ?0.740 and ?1.173 V, respectively, were observed. The peak at Epc =?0.740 V is attributable to the reduction of the Cd‐MT complex, whereas that at Epc=?1.173 V was assigned to the reduction of the Zn‐MT complex. Zn7‐MT exhibits only one redox wave with Epc=?1.198 V. The NCMFE was found to be more advantageous than thin mercury film electrode (MFE), because the pristine metal ions in MTs (e.g., Cd2+ and/or Zn2+) are not significantly replaced by Hg2+. The NCMFE is also complementary to Nafion‐coated bismuth film electrode in that it has a greater hydrogen overpotential, which allows the reduction of the Zn‐MT complex to be clearly observed. Moreover, intermetallic compound formation between Cd and Zn appears to be less serious at NCMFEs. Consequently, the amounts of Cd and Zn deposited into the electrode upon the reduction reactions can be quantified more accurately. 相似文献
3.
Wei Yue Bill L. Riehl Nebojsa Pantelic Kevin T. Schlueter Jay M. Johnson Robert A. Wilson Xuefei Guo Edward E. King William R. Heineman 《Electroanalysis》2012,24(5):1039-1046
Anodic stripping voltammetry (ASV) determination of Pb2+, Cd2+, and Zn2+ was done using metal catalyst free carbon nanotube (MCFCN) electrodes. Osteryoung square wave stripping voltammetry (OSWSV) was selected for detection. The MCFCNTs are synthesized via Carbo Thermal Carbide Conversion method which leads to residual transition metal free in the CNT structure. The new material shows very good results in detecting heavy metal ions, such as Pb2+, Cd2+, and Zn2+. The calculated limits of detection were 13 nM, 32 nM and 50 nM for Pb2+, Cd2+ and Zn2+, respectively with a deposition time of 150 s. 相似文献
4.
The quantification of the purified metallothionein (MT) component, isolated from the digestive gland of cadmium-exposed Mytilus galloprovincialis, is described based on the analysis of Cd(II) and SH-groups content, applying electrochemical methods. Advantages and disadvantages of the Brdika procedure for the determination of the MT content is discussed. The saturation of binding positions of purified MT with Cd2+ ions can be directly followed voltammetrically. Irrespective of the MT concentration, the saturation with Cd2+ of in vivo induced mussel MT is achieved at a molar ratio of 5. Cd2+ ions are rapidly displaced from the Cd-Th complex after the addition of Pb2+ ions, which indicates the kinetically labile type of the complex. 相似文献
5.
Application of Novel Zn‐Ferrite Modified Glassy Carbon Paste Electrode as a Sensor for Determination of Cd(II) in Waste Water
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Dalibor M. Stanković Sandra Škrivanj Nenad Savić Aleksandar S. Nikolić Predrag Vulić Dragan D. Manojlović 《Electroanalysis》2014,26(7):1536-1543
This paper describes the preparation of a new sensor based on Zn‐ferrite modified glassy carbon paste electrode and its electrochemical application for the determination of trace Cd(II) ions in waste waters using differential pulse anodic stripping voltammetry (DPASV). Different Zn/Ni ferrite nanoparticles were synthesized and characterized using scanning electron microscopy (SEM) and X‐ray powder diffraction (XRPD). The prepared ferrite nanoparticles were used for the preparation of Zn‐ferrite‐modified glassy carbon paste electrode (ZnMGCPE) for determination of Cd(II) at nanomolar levels in waste water at pH 5. The different parameters such as conditions of preparation, Zn2+/Ni2+/Fe2+ ratio and electrochemical parameters, percentage of modifier, accumulation time, pH and accumulation potential were investigated. Besides, interference measurements were also evaluated under optimized parameters. The best voltammetric response was observed for ZnFe2O4 modifier, when the percentage of modifier was 3 %, accumulation time 9 min, pH of supporting electrolyte 5 and accumulation potential ?1.05 V. Thus prepared electrode displays excellent response to Cd(II) with a detection limit of 0.38 ppb, and selective detection toward Cd(II) was achieved. 相似文献
6.
Sebojka Komorsky-Lovri Marko Branica 《Fresenius' Journal of Analytical Chemistry》1994,349(8-9):633-638
The influence of surface active substances (SAS) (Triton X-100, sodium dodecyl sulfate and dodecyl pyridinium chloride (DPC)) on the potentiometric stripping analysis (PSA), square-wave voltammetry (SWV) and anodic stripping square-wave voltammetry (ASSWV) of Cd2+, Cu2+, Zn2+ and Bi(III) are measured for various contact times and detergent concentrations. Diagnostic criteria for the presence of SAS in electrolytes are reported. Zinc ions accumulate in the adsorbed layer of DPC, probably as a ZnCl+ complex. An anomalous dependence of zinc SWV peak currents on the delay time is observed. 相似文献
7.
Cyclic voltammetry of antimony was studied in aqueous media (HCl-LiCl) and in nonaqueous media after extraction with 20% tri-n-butylphosphate in toluene, with a rotating glassy carbon disc electrode. Reduction of antimony to the element in aqueous media is nearly reversible, but irreversible in nonaqueous media. Anodic stripping voltammetric and chronopotentiometric determinations were also studied in nonaqueous media; methanol and LiCI, NH4SCN or NH4NO3, were used as base electrolytes. In nonaqueous media, antimony can be determined down to concentrations of 1O−8 M by stripping voltammetry, and lO−7 M by stripping chronopotentiometry. Electrochemical stripping determinations of 10−6 M antimony(III) were not affected by Co2+, Ni2+, Cd2+, Zn2+ or As3+ (5 · 10−3 M), ag+ (4 · 10+4 M in stripping voltammetry or 10−3 M in stripping chronopotentiometry), Hg2+ (5 · 10−4M), Pb2+ (3 · 10−4 M), Cu2+ (1.5 · 10−4 M)Sn2+ and Sn4+ (7 · 10−4 M), Fe3+ (4 · 10−4 M), Au3+ (5 · 10−5 M) and Bi3+ (1.5 · 10−5 M). Thestripping chronopotentiometric determination showed better selectivity. 相似文献
8.
Weibin Chen D Scott Smith 《International journal of environmental analytical chemistry》2017,97(4):330-344
The effects of pH, metal ions (i.e. Cu2+, Cd2+, Pb2+ and Zn2+) and natural organic matter (i.e. Suwannee River natural organic matter standard [SRNOM]) on determination of thiol (i.e. reduced glutathione [GSH]) by cathodic stripping voltammetry were evaluated. pH was the most critical parameter to influence GSH voltammogram (i.e. peak shape, position and height). In presence of Cu and Cd, secondary peaks were found at [metal]/GSH > 1 due to formation of GSH complexes at pH = 8.0 (Cu and Cd) and 2.5 (Cu only). On the other hand, Pb showed negligible influence on GSH voltammogram at pH 8.0 and 2.5 within [Pb]/[GSH] = 0.01–2.0. Zn significantly reduced GSH peak height at pH 2.5 at [Zn]/[GSH] = 0.01–2.0. SRNOM peak significantly overlapped with GSH peak at pH 8.0 and [SRNOM] > 1 mg L?1 but was clearly separated from the GSH peak at pH 2.5. However, at pH 2.5, the presence of metal ions and/or SRNOM significantly underestimated GSH concentration (recovery = 21–69%), likely due to metal complexation with GSH and/or SRNOM adsorption onto Hg electrode. The effects of metal ions were minimised by the addition of EDTA. The interference induced by SRNOM adsorption was reduced as the [SRNOM] was reduced to 1 mg L?1 and the recovery was improved to 98%. 相似文献
9.
Mercury microelectrodes were prepared by ex situ deposition of Hg onto Pt microdiscs. By exploiting the known properties of microelectrodes in stripping analysis, an absolute method based on a simple equation derived from the stripping charge and the microelectrode steady-state current was assessed for the simultaneous quantification of Cd2+, Pb2+ and Cu2+ concentrations. The method was tested with synthetic solutions containing known amounts of Cd2+, Pb2+ and Cu2+. Then, it was used to determine the labile and total fractions of these metal ions in rain samples. The labile fractions were measured from samples at their natural pH while the total concentrations were determined from samples at pH=2. 相似文献
10.
Simultaneous Detection of Heavy Metals by Anodic Stripping Voltammetry Using Carbon Nanotube Thread
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Daoli Zhao Xuefei Guo Tingting Wang Noe Alvarez Vesselin N. Shanov William R. Heineman 《Electroanalysis》2014,26(3):488-496
Carbon nanotube (CNT) threads are a type of CNT arrays that consist of super long CNTs. CNT threads inherit the advantages of CNTs, while avoiding the potential toxicity caused by individual CNTs. Electrodes based on CNT threads were fabricated and used for simultaneous detection of trace levels of Cu2+, Pb2+ Cd2+ and Zn2+ by anodic stripping voltammetry (ASV). The detection limits are 0.27 nM, 1.5 nM, 1.9 nM and 1.4 nM for Cu2+, Pb2+, Cd2+ and Zn2+, respectively, in 0.1 M acetate buffer pH 4.5. The CNT thread electrode gives well‐defined, reproducible and sharp stripping signals for individual and simultaneous detection of heavy metals. 相似文献
11.
Kathryn E. Toghill Gregory G. Wildgoose Amir Moshar Chris Mulcahy Richard G. Compton 《Electroanalysis》2008,20(16):1731-1737
We report the simultaneous electroanalytical determination of Pb2+ and Cd2+ by square‐wave anodic stripping voltammetry (SWASV) using a bismuth nanoparticle modified boron doped diamond (Bi‐BDD) electrode. Bi deposition was performed in situ with the analytes, from a solution of 0.1 mM Bi(NO3)3 in 0.1 M HClO4 (pH 1.2), and gave detection limits of 1.9 μg L?1 and 2.3 μg L?1 for Pb(II) and Cd(II) respectively. Pb2+ and Cd2+ could not be detected simultaneously at a bare BDD electrode, whilst on a bulk Bi macro electrode (BiBE) the limits of detection for the simultaneous determination of Pb2+ and Cd2+ were ca. ten times higher. 相似文献
12.
The mordenite samples loaded with divalent nitrates of Mn, Co, Ni, Cu, Zn and Cd were investigated using FTIR and scanning electron microscopy (SEM) methods. It was found from FTIR spectra that in 3000-4000 cm−1 region of mordenite samples with similar water concentration ions, Mn2+, Co2+, Cu2+, and Zn2+ tend to break hydrogen bonds formed between water molecules and zeolite framework, whereas Ni2+ and Cd2+ accommodate to hydrogen bonds. From SEM results it was concluded, that ions Mn2+, Co2+, Zn2+ form innersphere complexes with oxygens from Brönsted acid sites, whereas Ni2+ and Cd2+ associate with Brönsted acid sites without exchange of protons. 相似文献
13.
A new kind of secondarily formed peaks was found in cyclic and stripping voltammetry in neutral sulphate, perchlorate and nitrate supporting electrolytes containing some divalent cations and a substance (for example O2), the reduction of which gives as a by-product OH? ions. The hydroxides deposited in the vicinity of the mercury electrode, in the course of a cathodic scan, react during the anodic scan according to the reaction Hg+Me(OH)2=Hg(OH)2+Me2++2e forming a new, separate anodic peak.It was found that silver exerts a catalytic effect on the reduction of NO3? ions on the mercury electrode. In neutral nitrate supporting electrolyte containing Ag+ ions the hydroxides of some cations (Cd2+, Zn2+, Mn2+, Co2+ and Ni2+) were deposited during the cathodic scan or during the preelectrolysis. Afterwards, in the course of the anodic scan, a new peak, of the kind described above, was observed. The same effect was formerly interpreted, for Zn2+ and Cd2+, as evidence for the formation of intermetallic compounds, AgZn and AgCd. 相似文献
14.
Dan Berggren 《International journal of environmental analytical chemistry》2013,93(3-4):133-148
Abstract A flow-injection/Donnan dialysis/differential pulse anodic stripping voltammetry system was developed for the determination of free cadmium concentrations, [Cd2+], in solutions containing organically complexed Cd(II). A small dialysis cell with a strong cation-exchange membrane separating the sample and the receiver channels, was equilibrated in a flow-injection system. The ionic strength of sample and receiver solutions was 0.1 M, with NaNO3 as the bulk electrolyte. By determining a constant fraction of the Cd2+ associated with the membrane phase, [Cd2+] of the samples could be measured. Experimentally determined [Cd2+] corresponded well with those calculated, using tabulated stability constants, when citric acid, nitrilotriacetic acid, and oxalic acid were added as ligands. Thus, negatively charged and uncharged complexes were excluded from the membrane. Using the experimental design presented, [Cd2+]>5 × 10×8 M could be determined, but there is a great potential for increasing the sensitivity of the method. In solutions containing 1.0 μM Cd(II) and 200 mg fulvic acid/l, the inorganic fraction (Cd2+ CdNO3 + decreased from 57% to 10% when the pH increased from 4.04 to 5.51. In a soil solution from an orthic podzol, having a high concentration of dissolved organic carbon (22.4 mM), the inorganic fraction constituted 53% of the total Cd(II) concentration. 相似文献
15.
Cadmium(II) compounds are carcinogens but only weakly mutagens. Because Cd(II) at low micromolar concentrations stimulates
cell growth and induces some proto-oncogenes with several mammalian cell lines, the stimulation of cell proliferation is discussed
as a major mechanism of the carcinogenicity of this metal. In the present work, the induction of the cellular proto-oncogenes
c-fos and c-jun by Cd(II) was studied in rat PC12 cells. Several cellular signal transduction elements were tested as mediators
of the proto-oncogene induction by cadmium. Cd(II) does not evoke mobilization of free intracellular Ca2+ in PC12 cells, and there was no impairment of the effect of Cd(II) by inhibitors of protein kinase A or of MAPK kinase. However,
bisindolylmaleimide I, a specific inhibitor of protein kinase C abolished the proto-oncogene induction by Cd(II). Hence, a
critical role for protein kinase C in the mitogenic effect of Cd(II) is inferred, and a substitution of structural Zn2+ ions by Cd2+ ions in this enzyme is discussed as the putative mechanism.
Received: 30 July 1997 / Revised: 9 October 1997 / Accepted: 11 October 1997 相似文献
16.
Cadmium(II) compounds are carcinogens but only weakly mutagens. Because Cd(II) at low micromolar concentrations stimulates
cell growth and induces some proto-oncogenes with several mammalian cell lines, the stimulation of cell proliferation is discussed
as a major mechanism of the carcinogenicity of this metal. In the present work, the induction of the cellular proto-oncogenes
c-fos and c-jun by Cd(II) was studied in rat PC12 cells. Several cellular signal transduction elements were tested as mediators
of the proto-oncogene induction by cadmium. Cd(II) does not evoke mobilization of free intracellular Ca2+ in PC12 cells, and there was no impairment of the effect of Cd(II) by inhibitors of protein kinase A or of MAPK kinase. However,
bisindolylmaleimide I, a specific inhibitor of protein kinase C abolished the proto-oncogene induction by Cd(II). Hence, a
critical role for protein kinase C in the mitogenic effect of Cd(II) is inferred, and a substitution of structural Zn2+ ions by Cd2+ ions in this enzyme is discussed as the putative mechanism.
Received: 30 July 1997 / Revised: 9 October 1997 / Accepted: 11 October 1997 相似文献
17.
Ren-Xia Xu Xin-Yao Yu Chao Gao Yu-Jing Jiang Dong-Dong Han Jin-Huai Liu Xing-Jiu Huang 《Analytica chimica acta》2013
Nanostructured magnesium silicate hollow spheres, one kind of non-conductive nanomaterials, were used in heavy metal ions (HMIs) detection with enhanced performance for the first time. The detailed study of the enhancing electrochemical response in stripping voltammetry for simultaneous detection of ultratrace Cd2+, Pb2+, Cu2+ and Hg2+ was described. Electrochemical properties of modified electrodes were characterized by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The operational parameters which have influence on the deposition and stripping of metal ions, such as supporting electrolytes, pH value, and deposition time were carefully studied. The anodic stripping voltammetric performance toward HMIs was evaluated using square wave anodic stripping voltammetry (SWASV) analysis. The detection limits achieved (0.186 nM, 0.247 nM, 0.169 nM and 0.375 nM for Cd2+, Pb2+, Cu2+ and Hg2+) are much lower than the guideline values in drinking water given by the World Health Organization (WHO). In addition, the interference and stability of the modified electrode were also investigated under the optimized conditions. An interesting phenomenon of mutual interference between different metal ions was observed. Most importantly, the sensitivity of Pb2+ increased in the presence of certain concentrations of other metal ions, such as Cd2+, Cu2+ and Hg2+ both individually and simultaneously. The proposed electrochemical sensing method is thus expected to open new opportunities to broaden the use of SWASV in analysis for detecting HMIs in the environment. 相似文献
18.
The anodic stripping voltammetric and chronopotentiometric determination of tin(IV) in aqueous and nonaqueous medium after its extraction using the rotating disc electrode made of glassy carbon with the mercury film was studied. The optimum composition of nonaqueous medium for the determination of tin is 0.2 M NaBr+5×10?5M Hg2+ in 20 ml of the extract +30 ml of methanol. Tin(IV) was determined by anodic stripping voltammetry or chronopotentiometry down to the concentration 10?7M. The selective determination of tin was studied. 10?6M of tin(IV) was determined with an error ±4–5% even in the presence of metals: Co2+, Ni2+, Cd2+, Zn2+ (5×10?3M), Ag+ and Pb2+ (5×10?4M), Cu2+ (1.5×10?4M), Sb3+ and Bi3+ (5×10?5M). 相似文献
19.
I. G. Borodkina A. S. Burlov G. S. Borodkin V. V. Chesnokov T. A. Kuzmenko A. I. Uraev E. V. Korshunova I. S. Vasil’chenko 《Russian Journal of General Chemistry》2016,86(4):876-884
New ligand systems based on 4-formyl-5-hydroxypyrazole and 1-aminobenzimidazole derivatives are synthesized. The obtained enamines and their Zn2+ and Cd2+ metal complexes of composition ML2 were investigated using the IR, heteronuclear (1H, 13C, 15N, 77Se, 113Cd) and two-dimensional NMR spectroscopy (COSY, HSQC, HMBC). The data of physicochemical investigations and quantum-chemical calculations showed that the ligands exist in the ketoamine tautomeric form. Quantum-chemical simulation of Zn(II) and Cd(II) complexes showed that the zinc complexes adopt the pseudo-tetrahedral and the cadmium complexes pseudo-octahedral configuration. 相似文献
20.
Michelle Delayette-Mills Lya Karm Gilbert E. Janauer Ping-Kwan Chan William E. Bernier 《Analytica chimica acta》1981,124(2):365-372
The in situ precipitation of traces of cadmium(II) and zinc(II) ions as hexacyanoferrates from aqueous matrices was studied on conventional polystyrene gel and macroporous cation- and anion-exchange resins. Coprecipitation with each other or with copper(II) ions present in binary cation resins or in solution, and the influence of added nonprecipitating ions of the same charge type such as magnesium(II) were investigated. Microporous (gel) cation exchangers gave reasonable recoveries and macroporous cation exchangers gave very good recoveries; but macroporous anion exchangers performed best, suggesting macroporous hexacyanoferrate(II) resin as an ideal phase for collection/preconcentration of traces of Cu2+, Cd2+, Zn2+, and possibly Co2+, Ni2+, and Pb2+ from waters. As expected, very low yields were obtained with conventional anion exchange resin in the hexacyanoferrate form. Uniform distribution of Cu2+, Zn2+, and Cd2+ over macroporous anion-exchange resin phases were established by means of electron probe scans and taken as evidence for the formation of a uniform, well-developed precipitate layer covering the entire resin particle surface. 相似文献