Mercury Film Electrode Research Articles

A stannum–bismuth composite film electrode for simultaneous determination of zinc(ii) and cadmium(ii) using differential pulse anodic stripping voltammetry

The development and use of 'green' electrode materials is extremely attractive for the routine use of disposable metal sensors. Bismuth is an environmentally-friendly element and a bismuth film electrode was proposed as an alternative to mercury film electrodes. Compared with bismuth, stannum is a more 'environmentally friendly' material. The stannum-bismuth composite film electrode prepared by the in situ electrodeposition of stannum and bismuth on the glassy carbon substrate is reported for the first time. Compared with bismuth film and stannum film electrodes, the stannum-bismuth composite film electrode revealed better electroanalytical performance, and can be used as a possible alternative electrode for electrochemical stripping analysis of trace heavy metals.

Simultaneous Determination of Lead and Cadmium in the Presence of Morin by Adsorptive Stripping Voltammetry with a Nafion-Ionic Liquid-coated Mercury Film Electrode

Simultaneous Determination of Lead and Cadmium in the Presence of Morin by Adsorptive Stripping Voltammetry with a Nafion-Ionic Liquid-coated Mercury Film Electrode

Electrochemical Modeling of the Silica Nanoparticle–Biomembrane Interaction

The interaction of amorphous colloidal silica (SiO(2)) nanoparticles of well-defined sizes with a dioleoyl phosphatidylcholine (DOPC) monolayer on a mercury (Hg) film electrode has been investigated. It was shown using electrochemical methods and microcalorimetry that particles interact with the monolayer, and the electrochemical data shows that the extent of interaction is inversely proportional to the particle size. Scanning electron microscopy (SEM) images of the electrode-supported monolayers following exposure to the particles shows that the nanoparticles bind to the DOPC monolayer irrespective of their size, forming a particle monolayer on the DOPC surface. A one-parameter model was developed to describe the electrochemical results where the fitted parameter is an interfacial layer thickness (3.2 nm). The model is based on the adsorptive interactions operating within this interfacial layer that are independent of the solution pH and solution ionic strength. The evidence implies that the most significant forces determining the interactions are van der Waals in character.

Bismuth film electrode for stripping voltammetric measurement of sildenafil citrate

A simple and fast procedure for measuring low concentration of sildenafil citrate (SC), also known as Viagra ®, at the ex situ prepared bismuth film electrode (BiFE) is demonstrated. The BiFE was prepared ex situ on the surface of a glassy carbon substrate electrode and employed in adsorptive cathodic stripping voltammetric mode in 0.1 M acetate buffer solution (pH 4.5) in the presence of dissolved oxygen. Electroanalytical properties of the BiFE were studied and compared with the ex situ prepared mercury film electrode, lead film electrode and with bare glassy carbon electrode. The BiFE revealed a LoD (3 σ) of 1.8 × 10 −8 mol L −1 using 120 s accumulation time and good linear response in the examined concentration range of 1.0 × 10 −7 to 1.0 × 10 −6 mol L −1 SC with a correlation coefficient ( R 2) of 0.995 using short accumulation time of 30 s. The obtained very good repeatability of 1.5% ( c = 1.0 × 10 −6 mol L −1, n = 15) corroborated potential applicability of the BiFE for measuring SC, for example in pharmaceutical formulations. A successful preliminary study using constant current chronopotentiometric stripping mode has been also carried out.

Scope of detection and determination of gallium(III) in industrial ground water by square wave anodic stripping voltammetry on bismuth film electrode

Gallium(III) in ground water may cause human health hazards due to the antineoplastic and antimicrobial activities of gallium. However, the exposure limit of Ga(III) has not been set. This paper demonstrates the scope of employing the square wave anodic stripping voltammetry (SWASV) on bismuth film electrode (BiFE) for selective and sensitive detection of Ga(III) as well as its accurate and precise determination. The key parameters were optimized and the bismuth film morphology was characterized. The performance of BiFE was also compared with that of the mercury film electrode (MFE). The performance of BiFE was also studied for interferences of Zn(II), Cd(II), Tl(I) and Cu(II) ions. Gaussian peak fitting was performed to improve the calibration curve and the fitting process revealed almost similar stripping peak heights as obtained from the experimentally observed data though slight improvement in calibration was obtained from the peak area analysis. A good linear dynamic range (R2=0.996) was obtained in the concentration range of 20–100μg/L with a limit of detection (LOD) of 6.6μg/L (S/N=3) of Ga(III). A relative standard deviation of 2.9% (n=10) was obtained for 20μg/L of Ga(III) solution. The practical analytical utility of the method was verified by the determination of Ga(III) in spiked water samples, where 100–105% recovery of Ga(III) was achieved.

Optimization of Nd(III) pre-concentration on a rotating disk mercury film electrode in aqueous solution

Abstract Current work indicates that trivalent lanthanides will consistently sorb to a rotating disk mercury film electrode in bulk aqueous solution thus allowing the user to pre-concentrate trivalent lanthanides for further separation. However, the mechanism of sorption to the mercury film is largely unknown, making it difficult if not impossible to predict a priori the conditions under which pre-concentration is optimized. In the present study, we explore some of the electrochemical factors affecting this pre-concentration process to optimize the technique for use in a wide variety of aqueous media. Trivalent neodymium (Nd(III)) is used as a model for the trivalent f-element cations. The factors investigated include pH of solution, rotation rate of the electrode, concentration of mercury, potential application waveforms, order of deposition, and time dependency.

구리수은막 전극에을 사용한 이소니아자이드의 전위차 역적정

구리수은막 전극(CBMFE)으로 전위차 역적정함으로써 이소니아자이드(INH)를 정량하는 간단하고 빠른 방법이다. 순수한 형태와 투약형태에 대해서 1.0-10.0 mg 범위에서 정량 할 수 있도록 적정조건을 설정하였다. 방법의 정밀도와 정확도는 통계적인 방법으로 평가되었으며, 정제와 시럽속에 함유된 INH 정량법은 F-시험과 t-시험을 통하여 영국약전(BP) 방법과 비교하였다. A simple, rapid potentiometric back titration of Isoniazid (INH) in the presence of Rifampicin (RIF) in tablets and syrups is described. The method is based on the oxidation of INH by a known excess of copper (II) ion and the back titration of unreacted copper (II) ion potentiometrically with ascorbic acid using a lab-made Copper Based Mercury Film Electrode (CBMFE). The titration conditions have been optimized for the determination of 1.0-10.0 mg of INH in pure and dosage forms. The precision and accuracy of the method have been assessed by the application of lack-of-fit test and other statistical methods. Interference was not caused by RIF and other excipients present in dosage forms. Application of the method for INH assay in tablets and syrups was validated by comparison of the results of proposed method with that of the British Pharmacopoeia (BP) method using F- and t- statistical tests of significance.

High throughput systems for screening biomembrane interactions on fabricated mercury film electrodes

A sensing system for the rapid on-line screening of lipids and biomembrane active compounds in water samples has been successfully developed. The sensor consists of a flow cell and incorporated wafer-based device with on-chip mercury on platinum (Pt/Hg) working electrode and platinum (Pt) auxiliary and pseudo-reference electrodes. To optimise system performance, the following experiments were carried out: (i) Deposition and removal of phospholipid layers on and from Pt/Hg electrodes respectively, (ii) Effect of electrode size on signal, (iii) Monitoring of different phospholipids deposited in flow cell and, (iv) Detection of phospholipid monolayer interaction with representative compounds. The results showed that: (i) Miniaturisation and ruggedisation of the mercury (Hg)/phospholipid system has been successfully achieved, (ii) Rapid cyclic voltammetry facilitates repetitive dioleoyl phosphatidylcholine (DOPC) monolayer formation on Hg from aqueous DOPC dispersion and, (iii) The device responds selectively to organic compounds injected into electrolyte flow.

Metallo-Graphene Nanocomposite Electrocatalytic Platform for the Determination of Toxic Metal Ions

A Nafion-Graphene (Nafion-G) nanocomposite solution in combination with an in situ plated mercury film electrode was used as a highly sensitive electrochemical platform for the determination of Zn2+, Cd2+, Pb2+ and Cu2+ in 0.1 M acetate buffer (pH 4.6) by square-wave anodic stripping voltammetry (SWASV). Various operational parameters such as deposition potential, deposition time and electrode rotation speed were optimized. The Nafion-G nanocomposite sensing platform exhibited improved sensitivity for metal ion detection, in addition to well defined, reproducible and sharp stripping signals. The linear calibration curves ranged from 1 μg L−1 to 7 μg L−1 for individual analysis. The detection limits (3σ blank/slope) obtained were 0.07 μg L−1 for Pb2+, Zn2+ and Cu2+ and 0.08 μg L−1 for Cd2+ at a deposition time of 120 s. For practical applications recovery studies was done by spiking test samples with known concentrations and comparing the results with inductively coupled plasma mass spectrometry (ICP-MS) analyses. This was followed by real sample analysis.

The determination of molybdenum in selected mushrooms by stripping voltammetry

Abstract The highly sensitive method of adsorptive stripping voltammetry (AdSV), with differential pulse steps, was performed at a mercury film electrode and has been applied here for the determination of trace molybdenum content in selected wild mushrooms. Fruiting body caps of 12 selected macrofungi species from Basidiomycetes have been investigated. Molybdenum content of investigated samples was determined in the range of 0.006 to 0.38 mg kg−1 of dry matter. The highest value of molybdenum content was found in Leccinum rufum and the lowest in Lactarius deliciosus.

Determination of the Antiretroviral Drug Nevirapine in Diluted Alkaline Electrolyte by Adsorptive Stripping Voltammetry at the Mercury Film Electrode

This paper describes a stripping method for the determination of nevirapine at the submicromolar concentration levels. The method is based on controlled adsorptive accumulation of nevirapine at thin-film mercury electrode, followed by a linear cyclic scan voltammetry measurement of the surface species. Optimal experimental conditions include a 2.0 x 10(-3) mol L(-1) NaOH solution (supporting electrolyte), an accumulation potential of -0.20 V, and a scan rate of 100 mV s(-1). The response of nevirapine is linear over the concentration range 0.01-0.14 ppm. For an accumulation time of 6 minutes, the detection limit was found to be 0.87 ppb (3.0 x 10(-9) mol L(-1)). More convenient methods to measure the nevirapine in presence of the efavirenz, acyclovir, didanosine, indinavir, nelfinavir, saquinavir, lamivudine, zidovudine and metals ions were also investigated. The utility of this method is demonstrated by the presence of nevirapine together with ATP or DNA.

Determination of efavirenz in diluted alkaline electrolyte by cathodic adsorptive stripping voltammetry at the mercury film electrode

A stripping method for the determination of the antiretroviral drug efavirenz at the submicromolar concentration levels in diluted alkaline electrolyte is described. Optimum experimental conditions were: 2.0 × 10-3 mol L-1 NaOH, accumulation potential of -0.10 V, pulse amplitude of 50 mV and scan rate of 50 mV s-1. The response is linear over the concentration range of 0.01-0.25 ppm. For an accumulation time of 10 min, the limit of detection was 1.0 ppb (3.0 × 10-9 mol L-1). The most convenient conditions to measure the efavirenz concentration in the presence of ATP, DNA, several metals, and other antiviral drugs was also investigated. The utility of the method is demonstrated by the determination of efavirenz in a synthetic mixture containing both lamivudine and zidovudine, which are frequently used in the clinic in association with efavirenz as part of highly active antiretroviral therapy (HAART).

Determination of the Antiretroviral Drug Zidovudine in Diluted Alkaline Electrolyte by Adsorptive Stripping Voltammetry at the Mercury Film Electrode

This paper describes a stripping method for the determination of zidovudine at the submicromolar concentration levels. This method is based on the controlled adsorptive accumulation of zidovudine at the thin-film mercury electrode, followed by a linear-sweep stripping voltammetry measurement of the surface species. Optimal experimental conditions include a NaOH solution of 2.0 × 10–3 mol●L–1 (sup-porting electrolyte), an accumulation potential of –0.30 V and a scan rate of 100 mV?s–1. The response of zidovudine is linear over the concentration range 0.01 - 0.08 ppm. After an accumulation time of 5 minutes, the detection limit was found to be 0.67 ppb (2.5 × 10–9 mol●L–1). More convenient methods to measure zidovudine concentration in the presence of the didanosine, acyclovir, nevirapine, lamivudine, and efavirenz, were also investigated. The presence of zidovudine together with ATP or ssDNA demonstrates the utility of this method.

Determination of manganese and zinc in coastal waters by anodic stripping voltammetry with a vibrating gold microwire electrode

Environmental contextMetals in the marine environment play a role in biological processes but can also be toxic. An electrochemical method with a simple microwire electrode is presented that facilitates detection of zinc and manganese in coastal waters. The method is very sensitive and will likely lead to the development of an in-situ monitoring apparatus. AbstractA vibrating, gold, microwire electrode (VGME) is used here to detect low nanomolar levels of dissolved Mn by anodic stripping chronopotentiometry (ASC) and sub-nanomolar levels of dissolved Zn by anodic stripping voltammetry (ASV) in seawater. Mn is detected using a deposition potential (Edep) of –1.35 V, and Zn using Edep = –0.9 V, at pH 8. The method is an example of under-potential deposition (UPD), with positive shifts of the metal oxidation potentials of 0.4–0.6 V compared to the mercury electrode. The limits of detection for Mn (1.4 nM) and for Zn (0.3 nM) in seawater with a 300-s plating time, are better than achieved using other non-mercury based electrodes and nearly as good as a mercury film electrode for Zn. The detection of sub-nanomolar Mn is subject to an unusual interference by arsenate, which lowers the sensitivity when the deposition time is extended beyond 300 s. The VGME has advantages related to robustness, stability and ease of use (no polishing, simple regeneration) facilitating on-site and in-situ use. Zn and Mn are readily measured in seawater of natural pH without the need for reagents, facilitating use of this method in a system for in-situ monitoring. The methods are applied here to coastal seawater (Liverpool Bay, Irish Sea) and can be used for freshwaters such as river water.

Applications analytiques des films minces de mercure protégés par du fibrinogène pour la détermination du plomb et du cadmium dans des échantillons d’eaux usées et d’eaux de mer

Analytical application of fibrinogen-coated mercury film electrodes for the detection of lead and cadmium in water samplesThe aim of this study was the development of sensor based on fibrinogen (Fbg) coated mercury film electrodes at carbon paste electrode in the perspective of in-field stripping analysis of heavy metals in complex matrix. The preparation, optimization and characterization of coatings of Fibrinogen (Fbg) for the modification of thin mercury film electrodes and its application for the detection of trace metals have been described . The modified carbon paste electrode was prepared by a simple adsorption of fibrinogen from an aqueous solution containing an adequate quantity of fibrinogen. The Mercury film was then prepared by electrodeposition through the fibrinogen coating. The experimental parameters such as concentration of fibrinogen, deposition time and deposition potential were investigated. The performance of this electrode is evaluated in a presence of different surfactants such as gelatine, albumin, SDS and Tween 20, while lead and cadmium were employed as test metal ions. Using selected conditions the limits of detection were 5.10-9 mol.L-1 and 2.10-8 mol.L-1 for lead and cadmium, respectively. Since fibrinogen coated mercury film showed the best performance and increased efficiency against surfactants when comparing to the conventional mercury film, it was used for the analysis of trace metals in environmental samples of waters and industrial effluents.

Study on simultaneous measurements of trace gallium(III) and germanium(IV) by adsorptive stripping voltammetry using mercury film electrode

Simultaneous adsorptive stripping voltammetric method for the determination of trace gallium(III) and germanium(IV) based on the adsorption of gallium(III) and germanium(IV)-catechol complex on the cyclic renewable mercury film silver based electrode (Hg(Ag)FE) is presented. The calibration graph is linear from 1.25 nM (0.09 μg L−1) to 90 nM (6.27 μg L−1) with correlation coefficient of 0.999 for gallium and from 2.5 nM (0.18 μg L−1) to 160 nM (12.3 μg L−1) with correlation coefficient of 0.998 for germanium for a preconcentration time of 30 s. The detection limit for a preconcentration time of 60 s is as low as 25 ng L−1 for gallium and 58 ng L−1 for germanium. The proposed method was successfully applied by studying the natural samples and simultaneous recovery of Ga(III) and Ge(IV) from spiked water and sediment samples.

Determination of baicalin in Shuanghuanglian oral liquid on composite mercury film electrode based on chemical modfied

A novel Eu-PB composite mercury film electrode (GC/Eu-PB/MFE) based on chemical modified was developed for the determination of baicalin and the investigation of its the electrochemical behavior. Cyclic voltammetry and differential pulse voltammetry were used. The adsorption characteristic of baicalin was observed in Britton-Robinson buffer solution (pH 6.0) at GC/Eu-PB/MFE. The reduction peak of baicalin was observed at -1.22 V (vs SCE) and peak current was linear to the baicalin from 8.0 x 10(-9) to 1.0 x 10(-6) mol x L(-1) (r = 0.9992, n=8). The limit of detection was 1.2 x 10(-9) mol x L(-1) (S/N = 3). The average recovery was 99.83%, with RSD of 2.3% (n=8). The baicalin in Shuanghuanglian oral can be directly determined without pretreatment. The GC/Eu-PB/MFE was used to determine baicalin in Shuanghuanglian oral with good repeatability and high sensitivity. The method can be used for the quality control of Chinese traditional medicines containing Scutellaria baicalensis.

Preparation and Properties of Mercury Film Electrodes on Solid Amalgam Surface

AbstractA simple apparatus (electrolyzer) and a reliable procedure were developed for the preparation of mercury films of exactly defined thickness on a silver solid amalgam substrate. Constant concentration of Hg(II) in the electrolyzer is ensured by dissolution of an anode from silver paste amalgam. Small volume of electrolyte, which can be used repeatedly many times, and paste amalgam preventing the spillage of liquid mercury substantially decrease the danger of environmental contamination with mercury. Parameters and behavior of mercury film electrodes on silver solid amalgam substrate (MF‐AgSAE) were compared with polished silver solid amalgam electrode (p‐AgSAE) which does not contain liquid mercury, with mercury meniscus modified silver solid amalgam electrode (m‐AgSAE), and with hanging mercury drop electrode (HMDE). The height of anodic stripping voltammetric peaks divided by electrode area was highest for MF‐AgSAE and the width of those peaks, which determines the resolution of the method, was minimal at MF‐AgSAE. Available potential window of MF‐AgSAE in different supporting electrolytes is comparable with that of HMDE.

ChemInform Abstract: Alkali Metal Reduction Potentials Measured in Chloroaluminate Ambient- Temperature Molten Salts.

Alkali metal electrochemical reductions at a mercury film electrode (MFE) were studied in AlCl 3 :MEIC (MEIC=1-methyl-3-ethylimidazolium chloride) molten salts buffered to a neutral composition with MCl (M=Li, Na, K, Rb, and Cs). The MFE was formed by mercury deposition on a 127-μm iridium disk electrode. At the Ir-MFE, the reduction potentials for the Li, Na, K, Rb, and Cs amalgams were observed at -1.16, -1.26, -1.62, -1.67, and -1.75 V (vs. Al/Al(III)), respectively

Determination of histamine in cheese by chronopotentiometry on a thin film mercury electrode

Simple electroanalytical method for histamine determination based on its irreverse oxidation by a constant current on a thin film mercury electrode was developed in this work. Experimental parameters of chronopotentiometric analysis, such as concentration of the supporting electrolyte, initial potential and dissolution current were optimised. The optimal experimental parameters included an initial potential of −0.4 V and oxidation currents in the range from 3 to 30 μA in 0.02 mol/l sulphuric acid. After the optimisation of experimental parameters, the linear response was obtained in the range 2–90 mg/l of histamine with achieved detection limit of 1.31 mg/l of histamine. The method was applied for the determination of histamine in various types of cheese. Prior sample analysis the procedure for sample preparation was developed and included ultrasonically-assisted extraction and chromatographic separation on a thin layer. To our knowledge, histamine has never previously been determined on mercury electrodes nor by applying chronopotentiometric analysis, thus developed electroanalytical method represents an important contribution to electroanalytical practise. By applying the developed method it is possible to perform simple and fast cheese analysis. Furthermore, in comparison to competitive chromatographic techniques, chronopotentiometric method allows the analysis of foodstuffs under moderate price.