Preparation and Properties of Mercury Film Electrodes on Solid Amalgam Surface

Abstract

A 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.

Properties of thiolate monolayers formed on different amalgam electrodes

“…Preparation of different amalgam electrodes was described in detail in our previous papers [40][41][42]48]. Amalgam electrodes were electrochemically regenerated in a solution of 0.5 M NaOH in 48% ethanol containing the studied thiol: (a) before each measurement -regeneration potential E1 reg = À2200 mV (À1800 mV for m-BiAg-SAE and À1500 mV for m-CdSAE); regeneration time t1 reg = 120 s; E2 reg = À1500 mV; t2 reg = 30 s; (b) after each measurement: E3 reg = À2200 mV (À1800 mV for m-BiAgSAE and À1500 mV for m-CdSAE); t3 reg = 10 s. A full electrochemical regeneration of the electrode surface and its activation were performed in stirred 0.2 M KCl solution at E reg = À2200 mV for t reg = 300 s.…”

“…SAMs have been created using MFE based on silver [37], gold [38] and glassy carbon [39] (though mercury on glassy carbon does not form a continuous film, but rather a set of microdroplets [35]). Solid amalgams of different metals (SAE or MeSAE) are readily wetted by mercury, and therefore it is possible to prepare electrodes covered by mercury meniscus (m-MeSAE) or by mercury film (MF-MeSAE; here, Me = Ag, Au, Cu, Bi, Cd or others) [40][41][42][43]. Electrodes of paste amalgams (MeA-PE) are very similar to the mercury film electrodes and their great advantage consists in the simple mechanical renewal of the surface [44][45][46].…”

Using A Segmented Voltage Sweep Mode and A Gaussian Curve Fitting Method to Improve Heavy Metal Measurement System Performance

“…Similarly, digital potentiometer R 5 is used to control the ADC input voltage amplitude according to the ADC full-scale amplitude range. The MC that was used for testing purposes includes 3 electrodes with the following characteristics: a mercury film milli-electrode (2 mm), used as a working electrode [22], a platinum milli-electrode, used as counting electrode, and a glassy carbone milli-electrode, used as a reference electrode [23].…”

Utilização de eletrodos sólidos de amálgama para a determinação analítica de compostos orgânicos e inorgânicos

“…As condições para a deposição de filmes de mercúrio sobre MeSAE são descritas por Yosypchuk e Fójta. 45 A espessura do filme formado depende do tempo de deposição e da área do eletrodo. As condições da superfície do MeSAE, da solução, os potenciais e os tempos de deposição precisam ser rigorosamente controlados, afim de se manter a reprodutibilidade da formação dos filmes de mercúrio.…”