Electrochemical behavior of metallothioneins at mercury and carbon electrodes

Šestáková, Ivana; Miholová, D.; Vodičková, Hana; Mader, Pave

doi:10.1002/elan.1140070307

Cited by 39 publications

(10 citation statements)

References 29 publications

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“…An AC voltammogram obtained by SHACV in 1.0 mol/dm 3 HCl containing 1.0 µmol/dm 3 Os and 1.0 mmol/dm 3 Cys is shown in Fig. 2 ( ).…”

Section: Alternating Current Voltammetry (Acv)mentioning

confidence: 99%

“…Comparing the GCE and elucidating the role of Os and Cys were performed with the TMFE and its modified electrode, respectively. The measurements were carried out by DPV in the range of -0.3 V to -1.1 V. The voltammogram obtained using the GCE in 1.0 mol/dm 3 HCl containing 1.0 µmol/dm 3 Os and 1.0 mmol/dm 3 Cys is shown in Fig. 4a.…”

Section: Thin Mercury Film Electrodementioning

confidence: 99%

“…7 A GCE was polished with 5 µm aluminum powder and then cleaned with an ultrasonic wave cleaner in pure water before electrolytic deposition of the mercury. Electrolytic deposition was achieved by holding the GCE in 10 cm 3 of 0.1 mol/dm 3 HCl containing 25 mg/dm 3 Hg 2+ (0.01 mmol/dm 3 ) for 5 min with stirring at -0.90 V. The TMFE was then rinsed with pure water and stored in pure water until later use. A TMFE was freshly prepared for each experiment.…”

Section: Preparation Of Tmfe and Modificationmentioning

confidence: 99%

“…Cys was adsorbed on the TMFE by immersing it in a 1.0 mol/dm 3 Cys solution for 10 min, and then the electrode was rinsed with pure water. An Os-modified TMFE was prepared as follows: a few drops of 0.25 mM Os solution were put on the TMFE surface, and the TMFE was left for 10 min and then sufficiently rinsed with pure water.…”

Section: Preparation Of Tmfe and Modificationmentioning

confidence: 99%

“…Even now, the application of Brdicka's reaction is being used to determine 2 S-containing compounds and to characterize 3,4 the complexes formed by such compounds.…”

mentioning

confidence: 99%

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Electrode Behavior of an Osmium-Cysteine System on a Mercury Surface

Kawasaki

Kakizaki

et al. 1999

ANAL. SCI.

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Since Brdicka 1 reported a maximum wave due to an electrode reaction between sulfur-containing compounds and transition metals, such as Co and Ni, many studies utilizing such an electrode reaction have been carried out. Even now, the application of Brdicka's reaction is being used to determine 2 S-containing compounds and to characterize 3,4 the complexes formed by such compounds.In our previous paper 5 , we reported on the development of an analytical method for the quantification of osmium (Os) by applying Brdicka's electrode reaction using differential pulse (DP) polarography. The paper showed the following results: (1) a highly sensitive determination of Os is feasible by adding excess cysteine (Cys) into an Os solution under strongly acidic conditions, (2) the wave height depends on both the concentration of Os and Cys, (3) only S-containing compounds possessing a thiol group exhibit activity during an electrode reaction with Os(VIII), and (4) adsorption is observed around the peak potential based on the results of electrocapillary curves. Furthermore, we studied the valence states of Os and an interaction between Os and Cys correlated with the occurrence of the wave. 6 The following conclusions were drawn: (1) the contribution of each valency to the maximum wave height was in the order +6>+8>+4≈+3, and (2) in a strongly acidic solution, such as HCl, HNO 3 , HClO 4 and H 2 SO 4 , there were appreciable interactions between Os and Cys. However, many questions remain unsolved concerning this electrode reaction mechanism. The experimental conditions of this Os-Cys system differ from Brdicka's ordinary reaction and the applications are as follows: (1) The reduction wave occurs only when a strong acid is used as the electrolyte solution, (2) metal ions in the high valence states exhibit an activity for the occurrence of the maximum wave, and (3) an S-containing compound not possessing a thiol group, such as cystine, thiourea and thiosemicarbazide, did not yield a maximum wave in this electrode reaction with Os. Therefore, a study was carried out to further clarify this electrode reaction process.In this paper, the electrode reaction was studied using a hanging mercury-drop electrode (HMDE) and a thin mercury film electrode (TMFE), because these electrodes can easily utilize the effect of adsorption when compared with a dropping mercury electrode. Experiments Apparatus and reagentsVoltammograms were obtained using a Bioanalytical Systems incorporated (BAS) Model BAS 100W equipped with a computer. The working electrodes were a Metrohm Model E410 HMDE or a glassy carbon electrode (GCE). The electrochemical cell was equipped with a carbon rod auxiliary electrode and an Ag/AgCl reference electrode. Osmium(VIII) oxide (Os: Merck, Germany) and L-cysteine hydrochloride monohydrate (Cys: Wako Pure Chem. Ind., Ltd., Japan) were employed. All other chemicals were of analytical reagent grade and used without further purification. Nitrogen gas was used for deaeration of the electrolyte solution. The water used for all prepar...

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“…An AC voltammogram obtained by SHACV in 1.0 mol/dm 3 HCl containing 1.0 µmol/dm 3 Os and 1.0 mmol/dm 3 Cys is shown in Fig. 2 ( ).…”

Section: Alternating Current Voltammetry (Acv)mentioning

confidence: 99%

Section: Thin Mercury Film Electrodementioning

confidence: 99%

Section: Preparation Of Tmfe and Modificationmentioning

confidence: 99%

Section: Preparation Of Tmfe and Modificationmentioning

confidence: 99%

“…Even now, the application of Brdicka's reaction is being used to determine 2 S-containing compounds and to characterize 3,4 the complexes formed by such compounds.…”

mentioning

confidence: 99%

See 3 more Smart Citations

Electrode Behavior of an Osmium-Cysteine System on a Mercury Surface

Kawasaki

Kakizaki

et al. 1999

ANAL. SCI.

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Constant Current Chronopotentiometric Stripping Analysis of Bioactive Peptides at Mercury and Carbon Electrodes

et al. 1998

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Constant current derivative chronopotentiometric stripping analysis (CPSA) was used to study bioactive peptides [Lys 8 ]-vasopressin and angiotensin II at carbon paste electrode (CPE) and hanging mercury drop electrode (HMDE). Both peptides contain a single tyrosine residue which is oxidized at CPE close to þ0.6 V (against Ag/AgCl/3 M KCl electrode) producing peak Y; this peak was by about 15 mV more positive in vasopressin than in angiotensin II. At HMDE vasopressin yielded peak S due to the reduction of the disulfidic bond in the peptide. No peak S was observed with angiotensin II as it does not contain any cystine/cysteine residues. Vasopressin produced different catalytic hydrogen reduction signals in media with cobalt ion and in media not containing any metal ion. The signal produced in the latter media (peak H), which appeared close to ¹1.7 V, was well separated from the background. No catalytic hydrogen reduction signal was obtained with angiotensin II. The above mentioned CPSA signals can be applied for the determination of the respective peptide at nanomolar concentrations. The least sensitive peak S appears which requires at least 100 nM vasopressin concentration at moderate accumulation time. By two orders of magnitude, higher sensitivities can be obtained with peaks Y and H. In measuring these peaks CPSA shows significant advantages over the voltammetric stripping techniques.

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Voltammetric Methods for Speciation of Plant Metallothioneins

1998

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Cd, Cu and Zn complexes of two synthetically prepared peptides, (g-Glu-Cys) 2 -Gly and (g-Glu-Cys) 3 -Gly, were studied as models of plant metallothioneins by several voltammetric methods. Reduction peak of the complex in which the stechiometric ratio of molar concentrations of Cd(II) and peptide corresponds to coordination of one Cd(II) by four sulfur atoms (E p = ¹814 mV to ¹910 mV, DPV) is suitable for speciation. CSV after adsorption of Cu(I) complex on HMDE is also convenient, and two peaks (E p = ¹817 mV to ¹850 mV and E p = ¹940 mV to ¹953 mV) are attributed to plant MT with Cu(I). Cd and Cu complexes can be distinguished by different dependences for adsorptive accumulation of complexes on HMDE. In both cases the presence of zinc ions interferes with voltammetric speciation. Results of voltammetric studies were applied to the analysis of algal extracts, prepared from alga Chlorella, which was grown in cadmium enriched medium. Successful voltammetric identification of plant metallothionein in this type of material has been performed, in agreement with results from AAS and UV spectroscopy.

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Electrochemical behavior of metallothioneins at mercury and carbon electrodes

Cited by 39 publications

References 29 publications

Electrode Behavior of an Osmium-Cysteine System on a Mercury Surface

Electrode Behavior of an Osmium-Cysteine System on a Mercury Surface

Constant Current Chronopotentiometric Stripping Analysis of Bioactive Peptides at Mercury and Carbon Electrodes

Voltammetric Methods for Speciation of Plant Metallothioneins

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