Characterization and utilization of a long-lasting sessile-drop mercury electrode in differential pulse anodic-stripping voltammetric subtrace metal analysis of natural waters (original) (raw)
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A new mercury drop electrode for trace metal analysis
Analytica Chimica Acta, 1997
A new mercury drop electrode, model-l (MDE-1, Eco Chemie, Utrecht, Netherlands) is described. The sensitivity and the reproducibility of the electrode were tested for the determination of dissolved trace metals in natural aquatic systems using differential pulse anodic stripping voltammetry (ASV). The measurements were performed at pH=7.8 using a quartz cell, with a plastic stirrer and a glass reference electrode. The results obtained showed significant adsorption of the dissolved trace metal. The adsorption mainly takes place at the surface of the cell assembly (a plastic stirrer and a reference electrode made of glass), whereas only 1.5% of dissolved copper(I1) is adsorbed on the walls of the quartz cell. The adsorption of trace metals is significantly suppressed when the plastic stirrer and the sinter glass tip of the reference electrode are made of quartz. The reproducibility of the current response of the repetitive measurements of anodic peak currents of the acidic solution for the concentration range between 1 OF7 and 2x lo-" M Cd*+ showed variation coefficients from 0.7% to 3.5%, respectively. The MDE-1 detection limit of 2.5 x 10-l' M Cd*+ was obtained under the given experimental conditions.
Application of stripping voltammetry for the determination of mercury
Electroanalysis, 1995
A method for detecting low concentrations of mercury ions with the help of direct current anodic stripping voltammetry (DCASV) is proposed. For this method, gold and gold-plated electrodes are used. To eliminate the influence of interfering organic surfactants, electrochemical method is used for the probe preparation. Less interference by inorganic substances is attained by the introduction of an additional state in the electrolysis at constant potential after pre-electrolysis, by which interfering elements are stripped from the deposit while mercury remains on the electrode. The lowest detection limit obtained was 0.16 pg/L using a gold electrode and a graphite electrode impregnated with a mixture of an epoxy resin and polyethylenamine with a gold cover. The latter electrode can be used for fifty analyses without changing the gold covering. The proposed method was used for the analysis of food, sewage, and drinking water.
Differential Pulse Anodic Stripping Voltammetry for Mercury Determination
Acta Chemica Iasi, 2015
and a platinum wire electrode as auxiliary. A series of time depending equations for the pre-concentration and concentration steps were established, with the observation that a higher sensitivity can be obtained while increasing the pre-concentration time. DPASV were drawn using the CPE in 11.16 % coriander, as mercury complex, the voltamograms signals indicating mercury oxidation, with signal intensity increasing in time.
Electroanalysis, 1994
A glass!-carbon electrode (GCE) coated with 4.7.13.16.21,24-hexao?ia-l ,lO-diazabic)rclo[8.8.8]hexacosane, %?tofix-222, has been used for the ven. sensitive and selective analysis of very low levels of mercury. A detection limit lower than lo-" hl (<02 ppt) was obtained applying anodic stripping voltammetry (AS\.). The parameters that governed the sensitivity and possible interferences by other ions have been examined in detail. The electrode has been successfully applied for determining mercury in seawater, wastewater! and also in human saliva and amniotic fluid. The modified electrode exhibited high stability and, therefore. could be used repeatedly without mechanical regeneration.
International Journal of Biosensors & Bioelectronics, 2018
Electrochemical measurements are the most used and challenging approaches in trace elements analysis and speciation in complex natural samples. There is a wide research community that used electrochemical methods for studying critical environmental and biogeochemical processes, both natural and anthropogenically perturbed, that influence ecosystem services and human health. In recent years more attention is focused on development of environmentally friendly and sustainable chemical processes and tools which have aim to reduce negative footprint on the environment. Development in the electrochemistry is heading in this "green" direction, since EU regulations confined use of mercury, which has been established as the preferred tool/ sensor in electrochemical measurements. Therefore, development of new and more environmentally safely electrode materials is imperative. In this mini-review we discuss advantages of the mercury electrode use in measurements of organic material with surface active properties and sulfur compounds in natural waters.
Cadmium and lead complexation by anodic stripping voltammetry with a mercury microelectrode
Electroanalysis, 1996
Complexation reactions of lead by glutamic acid in KNOi 0.1 M and cadmium by glycine at two ionic strengths (0.1 M K N 0 3 and 2 x M borate buffer) have been used to : 1) compare the stripping response in DCASV (direct current anodic stripping voltammetry) and DPASV (differential pulse anodic stripping voltammetry) at large (hanging mercury drop electrode: HMDE) and small (thin film mercury microelectrode deposited on Pt/lr: pME) electrodes, 2) test classical DeFord-Hume's method with microelectrodes coupled to DCASV and DPASV, and 3) analyze the suitability of both electrodes HMDE and pME coupled to anodic stripping voltammetry to measurements in freshwaters. Indeed due to the mass transport characteristics at microelectrodes, the fraction of a metal which contributes to the current may well be different from that at a conventional size electrode. The obtained results are in all the situations consistent among themselves and in good agreement with literature.
Analytica Chimica Acta, 2011
The applicability of commercial screen-printed gold electrodes (SPGEs) for the determination of Hg(II) in ambient water samples by square wave anodic stripping voltammetry has been demonstrated. Electrode conditioning procedures, chemical and instrumental variables have been optimized to develop a reliable method capable of measuring dissolved mercury in the low ng mL −1 range (detection limit 1.1 ng mL −1 ), useful for pollution monitoring or screening purposes. The proposed method was tested with the NIST 1641d Mercury in Water Standard Reference Material (recoveries 90.0-110%) and the NCS ZC 76303 Mercury in Water Certified Reference Material (recoveries 82.5-90.6%). Waste water samples from industrial origin and fortified rain water samples were assayed for mercury by the proposed method and by a reference ICP-MS method, with good agreement. Screen printing technology thus opens a useful way for the construction of reliable electrochemical sensors for decentralized or even field Hg(II) testing.