Reduction Peak Potential Research Articles

Electrodeposition of iridium from composite ionic liquid

In order to study the electrodeposition process of iridium in composite ionic liquid, the effects of N, N-dimethylacetamide (DMAC) on the viscosity, conductivity and electrochemical stability of composite ionic liquid BMIC–BMIBF4, as well as the electrochemical behavior of IrCl3 in this system were studied. Iridium (Ir) coatings were deposited at different constant potentials and characterized by SEM and XRD. The results show that the addition of DMAC can evidently decrease the viscosity of the composite system, increase conductivity and improve electrochemical stability of the composite system. Cyclic voltammograms of a Au electrode illustrate that the process controlled by diffusion rate is irreversible with the average charge transfer coefficient of 0.170 and average diffusion coefficient of 1.096×10–6 cm2/s. In addition, SEM image shows that Ir film deposited at the reduction peak potential is dense and even, while XRD pattern shows that Ir deposit is polycrystalline structure.

Electrochemical and Computational Chemistry Study of Mn(β-diketonato)3 complexes

Nine different Mn(β-diketonato)3 complexes, with β-diketonato=dipivaloylmethanato, acetylacetonato, benzoylacetonato, dibenzoylmethanato, trifluoroacetylacetonato, trifluorothenoylacetonato, trifluorofuroylacetonato, trifluorobenzoylacetonato and hexafluoroacetylacetonato, were synthesized. The effect of the various substituents on the β-diketonato backbone of these complexes, on the ease of oxidation and reduction of the central metal in the nine different Mn(β-diketonato)3 complexes, was studied by means of electrochemistry. It was found that, when adding aromatic substituents to the backbone of the β-diketonato ligands of the complexes, the reduced/oxidized species were stabilized. It was also found that, when adding more electron withdrawing groups to the backbone of the β-diketonato ligands of the complexes, that Mn(β-diketonato)3 complex was more easily reduced at a higher potential. Good linear relationships and trends were obtained between the mean value of peak oxidation and reduction potential of the MnIII/MnII redox couple, and various electronic parameters and DFT calculated energies.

Electrocatalytic Reduction of 2, 2, 2–Trichloro-1, 1-Bis (4-Chlorophenyl) Ethanol (Dicofol) in Acetonitrile-Aqueous Solution Using Cyanocobalamin as a Catalyst

This paper reports on the catalytic behaviour of cyanocobalamin (VB12) towards the reduction of polyhalogenated organic pollutant 2, 2, 2–trichloro-1,1-bis (4-chlorophenyl) ethanol (dicofol) in acetonitrile-aqueous solution containing 0.1M KNO3 supporting electrolyte. Dicofol is a persistent, toxic organochlorine acaricide used in agriculture and horticulture to control spider mites and soft-bodied mites. Due to the chronic toxicity, bioaccumulation and carcinogenity, determination of persistent organochlorine pesticides like dicofol has become very important. The available methods are disfavored as they lack necessary simplicity, inexpensiveness and environmentally friendliness for routine analysis, and consequently, electrochemical methods have shown to be possible alternatives. Cyanocobalamin being one of the most nucleophilic species known in aqueous solution can undergo nucleophilic reactions which are efficient for dehalogenation of various organic halides. Direct reduction of cyanocobalamin exhibited a quasi-reversible two-electron reduction with the oxidation state of the central cobalt species going from +3 to +1 and E½ of 0.696 ± 0.009 V. Dicofol exhibited a single two-electron reduction peak at -1.182±0.029 V vs SCE. The E½ was -1.074 V and the diffusion coefficient was 2.21x10-5 cm2s-1. Addition of dicofol to solution of cyanocobalamin resulted in a large reduction peak at around the reduction peak potential of cyanocobalamin (-0.732±0.018V versus SCE for six scan rates). This makes it clear that when cyanocobalamin is adsorbed on pyrolytic graphite electrode, it causes the lowering of overpotential for the reductive decomposition of dicofol by approximately 0.45 V and therefore ΔG was about 1½ times lowered. The decrease in ΔG implies that electrocatalysis is more kinetically favourable compared to direct electrochemical activation of carbon–halogen bonds.

Polarographic determination of DNA based on its interaction with the phenanthroline-zinc(II) complex

By using the linear sweep voltammetric technique, a phenanthroline (Phen) and zinc(II) (Phen-Zn(II)) complex was used as the electrochemical probe for the determination of double-stranded (ds) DNA. In pH 9.0 Britton- -Robinson (B-R) buffer solution, Phen can interact with Zn(II) to form a stable electroactive [Phen-Zn(II)] complex, which had a sensitive second order derivative polarographic reductive peak at -1.300 V (vs. SCE). After the addition of dsDNA into a solution of Phen-Zn(II) complex, the reduction peak current decreased with a negative shift of the reduction peak potential and without the appearance of new peaks. The results showed that a new supramolecular complex was formed via interaction of the Phen-Zn(II) complex with dsDNA. The conditions of interaction and the electrochemical detection were carefully investigated. Under the optimum conditions, the decrease in the reduction peak current was directly proportional to the dsDNA concentration in the range of 0.4-18.0 mg L-1 with the linear regression equation: ?Ip?/nA = 349.48 + + 84.647(c/mg L-1) (n = 13, ? = 0.991) and a determination limit of 0.20 mg L-1 (3?). The relative standard deviation (RSD) for 10 parallel determinations of 10.0 mg L-1 dsDNA was found to be 2.03 %. The method was successfully applied to the detection of synthetic samples with satisfactory results.

Biodegradation of Bis-Azo Dye Reactive Black 5 by White-Rot Fungus Trametes gibbosa sp. WRF 3 and Its Metabolite Characterization

The culture ofTrametes gibbosasp. white-rot fungi (WRF) 3 under mesophilic conditions can lead to the degradation of azo dye compounds. This ability of T. gibbosa sp. WRF 3 is attributed to the released enzymes that are able to catalyze the structural degrada- tion of the azo dye compound. The effect of environ- mental factors such as carbon sources, nitrogen sources, and pH of growth medium were investigated in this research.Theadditionof20g/L glucose(carbonsource) and yeast extract (nitrogen source) at pH 5 of growth medium enhanced the decolorization of Reactive Black 5 (RB5) dye up to 87.07 % within 30 days ofincubation. The decolorization of RB5 can be analyzed using UV- vis spectroscopy and differential pulse cathodic strip- ping voltammetry (DPCSV). The maximum absorbance of RB5 was at 597 nm and decreased after the dye was treated with T. gibbosa sp. WRF 3. In the voltammetric analysis, we examined the effect of pH of Britton- Robinson buffer (BRB) medium on the detection of bis-azo compound of RB5. A stock solution of RB5 was used in the study, and it showed two reduction peak potentials at �0.5 and �0.7 V which attributed to the bis-azo bond, whereas the metabolic product showed one reduction peak at �0.6 V. The GC-MS mass spec- trum confirmed the formation of metabolites at tR 4.63 min and m/z of 73 after 30 days of incubation which was sec-butylamine.

Determination of Cobalt(III) Ion Using a Nafion-Ethylenediamine Modified Glassy Carbon Electrode

Determination of cobalt(III) ion with a perfluorinated sulfonated polymer-ethylenediamine (nafion-en) modified glassy carbon electrode is studied. It is based on the chemical reactivity of an immobilized layer, nafion-en, to yield complex <TEX>$[Co(en)_3]^{3+}$</TEX>. The reduction peak potential by differential pulse voltammetry (DPV) is observed at <TEX>$-0.437{\pm}0.047$</TEX> V (vs. Ag/AgCl). The linear calibration curve is obtained in cobalt(III) ion concentration range <TEX>$1.0{\times}10^{-8}{\sim}1.0{\times}10^{-3}M$</TEX> (<TEX>$5.893{\times}10^{-12}{\sim}5.893{\times}10^{-5}g/mL$</TEX>).

Studies of Metal Electrodeposition in Adiponitrile

The solvent system adiponitrile (ADN) / tetraethylammonium tetrafluoroborate (TEA BF4) has been used to study the electrodeposition of various metals at both platinum and glassy carbon electrodes. Well-defined stripping peaks were found at each electrode for AgNO3 and Cu(NO3)2 systems, with slower electrodeposition kinetics at glassy carbon. For Hf(TfO)4 and Al(TfO)3, there is noticeable anodic activity after the initial reduction process; however, the stripping process is not as definite as in the silver and copper cases. Nucleation plots have been used to determine that copper(II) reduction at glassy carbon involves progressive nucleation at the peak reduction potential, while at platinum an instantaneous pathway is followed.

Reduction of Graphite Oxide Using Ammonia Solution and Detection Cr(VI) with Graphene-Modified Electrode

Graphene (reduction of graphite oxide, rGO) was successfully prepared by using ammonia solution (NH3·H2O) as a reductive agent. The molecular structure and electrochemical properties of rGO were characterized by FTIR, XRD, Raman, SEM, EIS, and cyclic voltammetry (CV). The electrochemical sensing of chromium (Cr(VI)) at graphene-modified electrode (rGO/GCE) was investigated by differential pulse cathodic stripping voltammetry. The result showed that the charge transfer resistance of [Fe(CN)6]3−/4− at rGO/GCE was 75.02 Ω·cm2 decreased by about nine times comparing as that of GCE. The reduction peak potential of Cr(VI) at rGO/GCE was shifted positively by 116 mV and the peak current increased by about eight times. Meanwhile, the detection limit was 1.5 × 10−7 mol/L. It was worth noting that the synthesis of rGO by reducing GO with NH3·H2O was more friendly to environment and human health relative to hydrazine hydrate (NH2-NH2·H2O) or other poisonous reductants.

Electroanalysis of nitrobenzene derivatives and nitrite ions using silver nanoparticles deposited silica spheres modified electrode

An electrochemical sensor was developed for the detection of nitrobenzene derivatives and nitrite ions using silver nanoparticles (Ag NPs) deposited on amine functionalized silica (SiO2) spheres modified electrode. The electrocatalytic reduction of nitrobenzene and oxidation of nitrite ions were studied using SiO2/Ag NPs at three different Ag concentrations (1, 2 and 3mM) modified electrodes. In electrocatalysis, a positive shift in the reduction peak potential for nitrobenzene and a significant increase in the catalytic oxidation current for nitrite ions were observed at these modified electrodes. An improved electrocatalytic activity for the reduction of nitrobenzene and oxidation of nitrite ions was achieved at the SiO2/Ag (3mM) NPs modified electrode due to the large number of Ag NPs deposited on SiO2 surface. The lowest experimental detection limits of 500nM for nitrobenzene derivatives and 1μM for nitrite ions at the SiO2/Ag NPs modified electrode were observed.

Enhanced reductive transformation of p-chloronitrobenzene in a novel bioelectrode–UASB coupled system

The laboratory-scale upflow anaerobic sludge blanket (UASB) reactor equipped with a pair of bioelectrodes was established for the enhancement of p-chloronitrobenzene (p-ClNB) reductive transformation via the electrolysis. Results showed that a stable COD removal efficiency over 99% and high p-ClNB transformation rate of 0.328h−1 were achieved in the bioelectrode–UASB coupled system with influent COD and p-ClNB loading rates of 2.1–4.2kgCODm−3d−1 and 60gm−3d−1, respectively. The bioelectrodes were supplied with a voltage of 2.5–5.0V and the effective current was above 2mA, which resulted in a continuous supply of H2. Compared with the traditional UASB reactor (R1), the production of H2 was promoted in the bioelectrode–UASB coupled system (R2), and was consumed as an internal electron donor for p-ClNB reductive transformation by anaerobic microbes simultaneously. Furthermore, the cyclic voltammetry curve (CV) analysis of biocathodes showed a positive shift in the reductive peak potential and a dramatic increase in the reductive peak current, which demonstrated the catalytic reduction of p-ClNB by biocathode in the combined system.

Deciphering characteristics of bicyclic aromatics--mediators for reductive decolorization and bioelectricity generation.

This first-attempt study quantitatively assessed electron-mediating characteristics of bicyclic aromatics - 1-amino-2-naphthol, 4-amino-1-naphthol (i.e., decolorized intermediates of azo dyes - orange I and II) for color removal and power generation in MFCs. According to cyclic-voltammetric profiles, the presence of reduction and oxidation peak potentials clearly suggested a crucial role of these intermediates as electron-shuttling mediators. Shake-flask cultures also showed that appropriate accumulation of 1A2N, 4A1N apparently enhanced color-removal efficiencies of bacterial decolorization. This study clearly suggested that suitable supplementation of electrochemically active electron shuttle(s) to dye-bearing MFCs is a promising strategy to stimulate reductive decolorization and bioelectricity generation.

Thermoresponsive Polymer Grafting from the Electrochemically Surface-Modified Graphite

It has been already achieved in our previous studies that the phenolic hydroxyl groups are introduced on carbon fiber by the electrooxidation of the LiNO3 containing electrolyte using the carbon fiber as an anode. In this study, we have first applied our procedure to the oxidation of graphite rod surface. The graphite rod was found to be readily oxidized under anodic conditions. In the XPS spectrum of the untreated graphite was observed a sharp peak at 285 eV. On the other hand, this peak broadened and shifted to high energy range after 0.5 F/mol of electricity based on LiNO3 was passed. The peak separation analysis of the C 1s spectrum of the oxidized graphite indicates that the spectrum can be charactrized as a combination of 4 peaks attributed to C-C (C=C) at 284.8±0.1 eV, C-O at 286.9±0.3 eV, C=O at 288.5±0.3 eV, and C(=O)O at 289.8±0.2 eV, and the intensity of the peak at 286.9 eV is highest. These results indicate that phenolic hydroxyl groups are mainly introduced on the graphite surface under the anodic oxidations. The polymerization with reversible addition-fragmentation chain transfer (RAFT) is an extremely versatile process for the synthesis of end-functional polymers and block copolymers. Trithiocarbonate derivatives have been reported to be effective as a chain transfer reagent (RAFT regent) for polymerization of styrene, acrylates, and acrylamides. On the anodically oxidized graphite were fixed 4-cyano-4-[(dodecylsulfanylthiocarbonyl)sulfanyl]pentanoyloxy groups by esterification with the corresponding acid chlorides. From the resulting RAFT reagent-modified graphite, several acrylamide monomers such as N-isopropyl acrylamide (NIPAAm) were polymerized under RAFT polymerization conditions to afford the corrsoponding thermoresponsive polymer-grafted graphites. In the mechanism of RAFT polymerization the propagating macroradical species migrate between the RAFT reagents fixed on the graphite and those in the solutions, and it is known that the molecular weights and repeat units sequence structures of the grafted polymers are almost same as those of the polymers recovered from the polymerization solution. Therefore the polymers were recovered from the polymerization solution and characterized. For instance, the molecular weight and dispersity index of the grafted PNIPAAm were estimated by GPC to be 6750 and 1.24 respectively. The RAFT reagent-modifified graphite and the polymer-grafted graphites were also analyzed by XPS. In S 2p spectrum of the RAFT reagent-modified graphite the peak attributed to thiocarbonylsulfanyl group was clearly observed at 163.6 eV. This peak was weakened and slightly shifted to higher energy range in the spectra of PNIPAAm-grafted graphite. Moreover the peaks attributed to the amide groups of PNIPAAm sequence were observed at 400.3 eV in N 1s spectra of the copolymer-grafted graphites. These results clearly indicate that the PNIPAAm is successfully grafted from the graphite by RAFT polymerization. The electron transfer to the substrates on the thermoresponsive polymer grafted graphite in aqueous media was then observed by cyclic voltammetry using 1,4-benzoquinone as a model substrate. Increases in peak current were observed from 15°C to 25°C in both of reduction and oxidation waves of 1,4-benzoquinone by using the PNIPAAm-grafted graphite as a working electrode. When the substrate was contacted with the PNIPAAm-grafted graphite below 5°C and then the temperature was raised to 45°C, the reduction peak potential was observed at -0.40 V. On the other hand, the peak potential was -0.32 V when the substrate was contacted with the graphite at 45°C. Trapping of the substrates into the polymer field on the graphite or blocking of the substrates from the graphite surface were confirmed by the change of the peak current and redox potential during the phase separation of the thermoresponsive polymers on the graphites.

Basicity and the electrochemical behavior of azulen-1-yl-thiazol-2-yl diazenes

The determination of pH values at the equivalence (isosbestic) point from the electronic spectra of several azulen-1-yl-thiazol-2-yl diazenes allowed the obtaining of their pKa values. All the studied compounds are very weak bases. The pKa values were correlated with the diazenes structure. The values for oxidation and reduction peak potentials are obtained from DPV curves. A good correlation was found between the calculated values for molecular orbitals energies and the experimental recorded data for the redox processes.

Electroanalysis of Unconventional (Herbal) Drugs Using Surface Modified Electrodes in Conjunction with Cyclic Voltammetry

In this paper we report on the use of surface modified electrodes in conjunction with cyclic voltammetry to study the redox profiles of quinine in unconventional drugs-herbal medicine. The unconventional drugs used in the study include cinchona bark and malbet. The results show quinine in cinchona is redox active with the oxidation and reduction potentials on bare carbon graphite electrode occurring at 0.495V and 0.345V respectively. The oxidation/reduction potential on bentonite modified electrode occurred at 0.450V/ (0.345V and -0.030V). It was observed that, when in contact with the bentonite over along period, quinine in cinchona is physi-sorbed. The redox process of the quinine extract is diffusion limited. In the case of malbet the quinine in Alstonia scholaris was detected . The other natural products in malbet appear not to be electroactive. The oxidation and reduction peak potential for quinine in alstonia scholaris appeared at 0.540V and 0.225V in 1M H2SO4 and 0.525V and 0.330 V in HCl.The malbet appears to ingress into bentonite lattice and is pre-concentrated in the bentonite hence, giving enhanced redox signals.The electrochemical signal obtained in malbet is attributed to quinine in Alstonia scholaris.

Fundamental Studies on Electrochemical Deposition of Lead from Lead Oxide in 2:1 Urea/Choline Chloride Ionic Liquids

Ionic liquids have shown to be environmental friendly electrolytes that are suitable for electrodeposition of metals. In this work, lead oxide (PbO) was dissolved in 2:1 mole ratio of urea/choline chloride (Urea/ChCl) eutectic mixture at different temperatures (343 to 363 K). Electrochemical measurement confirms that the reduction peak potential for Pb (II) to Pb at –0.43 V vs. Ag reference electrode. The reduction of Pb (II) to Pb is characterized as an irreversible process and controlled by diffusion of electroactive species in the electrolyte. The value of diffusion coefficient varies between 1.09 × 10−8 and 1.42 × 10−7 cm2/s at temperatures from 343 to 363 K, respectively. The activation energy of the reaction is 124.7 kJ/mol. Three-dimensional (3D) instantaneous nucleation and growth process is predominant at reduction potentials studied. The SEM images of the electrodeposits obtained at –0.5 to –1.1 V show dendritic-type morphology of Pb particles. The XRD and EDS analysis confirm that the electrodeposits are consisted of high-pure Pb metal.

Simultaneous voltammetric determination of dopamine and epinephrine in human body fluid samples using a glassy carbon electrode modified with nickel oxide nanoparticles and carbon nanotubes within a dihexadecylphosphate film.

A simple and highly selective electrochemical method was developed for the single or simultaneous determination of dopamine (DA) and epinephrine (EP) in human body fluids using a glassy carbon electrode modified with nickel oxide nanoparticles and carbon nanotubes within a dihexadecylphosphate film using square-wave voltammetry (SWV) or differential-pulse voltammetry (DPV). Using DPV with the proposed electrode, a separation of ca. 360 mV between the peak reduction potentials of DA and EP present in binary mixtures was obtained. The analytical curves for the simultaneous determination of dopamine and epinephrine showed an excellent linear response, ranging from 7.0 × 10(-8) to 4.8 × 10(-6) and 3.0 × 10(-7) to 9.5 × 10(-6) mol L(-1) for DA and EP, respectively. The detection limits for the simultaneous determination of DA and EP were 5.0 × 10(-8) mol L(-1) and 8.2 × 10(-8) mol L(-1), respectively. The proposed method was successfully applied in the simultaneous determination of these analytes in human body fluid samples of cerebrospinal fluid, human serum and lung fluid.

Electrodeposition of Ni–Co alloy films onto titanium substrate

Binary bright Ni–Co alloy films were electrodeposited on titanium in the chloride–sulfate electrolytes. The influences of Co2+ concentration, current density, and temperature on the Ni–Co alloy films electrodeposition were investigated. The films were analyzed by scanning electron microscope (SEM), energy dispersive spectroscopy (EDS), and X-ray diffraction (XRD). Cathodic polarization for Ni–Co codeposition was performed on Ti working electrodes. With the increase of Co2+ concentration, the Ni content in the films decreases and the current efficiency increases slightly. The Ni content increases with the increase of temperature, while it decreases with the increase of current density to a minimum and then increases. The cathodic reduction peak potential is measured to be −1.34 V. Anomalous deposition is found to occur in the Ni–Co codeposition. The SEM of Ni–Co alloy films shows that hydroxide particles are not present on the surface and fine grain, compact, smooth, and bright Ni–Co alloy films are obtained. The XRD result indicates that the deposited Ni–Co alloy film is Ni-solid solution with a face-centered cubic in structure.

Planar and Nonplanar Free‐Base Tetraarylporphyrins: β‐Pyrrole Substituents and Geometric Effects on Electrochemistry, Spectroelectrochemistry, and Protonation/Deprotonation Reactions in Nonaqueous Media

A series of planar and nonplanar free-base β-pyrrole substituted meso-tetraarylporphyrins were characterized by electrochemistry, spectroelectrochemistry, and protonation or deprotonation reactions in neutral, acidic, and basic solutions of CH2 Cl2 . The neutral compounds are represented as H2 (P), in which P represents a porphyrin dianion with one of several different sets of electron-withdrawing or -donating substituents at the messo and/or β-pyrrole positions of the macrocycle. The conversion of H2 (P) to [H4 (P)](2+) in CH2 Cl2 was accomplished by titration of the neutral porphyrin with trifluoroacetic acid (TFA) while the progress of the protonation was monitored by UV/Vis spectroscopy, which was also used to calculate logβ2 for proton addition to the core nitrogen atoms of the macrocycle. Cyclic voltammetry was performed after each addition of TFA or TBAOH to CH2 Cl2 solutions of the porphyrin and half-wave potentials for reduction were evaluated as a function of the added acid or base concentration. Thin-layer spectroelectrochemistry was used to obtain UV/Vis spectra of the neutral and protonated or deprotonated porphyrins under the application of an applied reducing potential. The magnitude of the protonation constants, the positions of λmax in the UV/Vis spectra and the half-wave or peak potentials for reduction are then related to the electronic properties of the porphyrin and the data evaluated as a function of the planarity or nonplanarity of the porphyrin macrocycle. Surprisingly, the electroreduction of the diprotonated nonplanar porphyrins in acid media leads to H2 (P), whereas the nonplanar H2 (P) derivatives are reduced to [(P)](2-) in CH2 Cl2 containing 0.1 M tetra-n-butylammonium perchlorate (TBAP). Thus, in both cases an electrochemically initiated deprotonation is observed.

Carboxyl hydrogel particle film as a proton source for electrode surface modification

Uniformly sized poly(N-isopropylacrylamide-co-acrylic acid) (NIPA/AA) hydrogel particles were synthesized as a solid-acid for electrode surface modification. Voltammograms of the NIPA/AA particle film-coated platinum electrodes showed the reduction of hydrogen ions which were supplied from the dissociation of carboxyl groups of the absorbed NIPA/AA particles. The reduction peak potentials at the particle film-coated cavity platinum electrode were observed around −0.38V. Compared with that observed at flat platinum electrode, the peak potentials were shifted in the positive direction by 0.19V. The peak currents were increased with increase in the amount of immobilized particle. The particle film worked as a source of supply of hydrogen ions for the electrochemical reduction of 1,4-naphthoquinone. The electrode surface pH was controlled to be 4.5 by NIPA/AA particle film in the neutral solution.

Application of Cupferron‐lead(II) Complex for the Electrochemical Determination of dsDNA

AbstractBased on the interaction of cupferron and lead(II) complex [Cup‐Pb(II)] with double‐stranded DNA (dsDNA) a new voltammetric method for the detection of DNA was described in this paper. In pH 4.0 HAc‐hexamine buffer solution, [Cup‐Pb(II)] complex showed a sensitive second order derivative polarographic reductive peak at ‐0.554 V (vs. SCE). After the addition of dsDNA into [Cup‐Pb(II)] mixture solution the reductive peak current decreased with the positive shift of reductive peak potential, which was the typical characteristic of intercalation mode. Under the optimum conditions, the decrease of reductive peak current was directly proportional to the dsDNA concentration in the range from 1.0 to 25.0 mg/L with the linear regression equation as ΔIp″ (nA) = 129.30 + 62.51 C (mg/L) (n = 13, γ = 0.991). The detection limit of 0.90 mg/L (3σ) and the relative standard derivation (RSD) of 2.43% for 10 parallel determinations of 10.0 mg/L dsDNA were found. The method was successfully applied to synthetic samples with good results, and the stoichiometry of dsDNA with [Cup‐Pb(II)] complex was calculated by the voltammetic data with the binding number as 2 and the binding constant as 2.82 × 109.