“Green” Three-Electrode Sensors Fabricated by Injection-Moulding for On-Site Stripping Voltammetric Determination of Trace In(III) and Tl(I)

This work reports the fabrication of a new environmentally friendly three-electrode electrochemical sensor suitable for on-site voltammetric determination of two toxic emerging ‘technology-critical elements’ (TCEs), namely indium and thallium. The sensor is fully fabricated by injection-moulding and features three conductive polymer electrodes encased in a plastic holder; the reference electrode is further coated with AgCl or AgBr. The sensor is applied to the determination of trace In(III) and Tl(I) by anodic stripping voltammetry using a portable electrochemical set-up featuring a miniature smartphone-based potentiostat and a vibrating device for agitation. For the analysis, the sample containing the target metal ions is spiked with Bi(III) and a bismuth film is electroplated in situ forming an alloy with the accumulated target metals on the working electrode of the sensor; the metals are stripped off by applying a square-wave anodic voltametric scan. Potential interferences in the determination of In(III) and Tl(I) were alleviated by judicious selection of the solution chemistry. Limits of quantification for the target ions were in the low μg L−1 range and the sensors were applied to the analysis of lake water samples spiked with In(III) and Tl(I) with recoveries in the range of 95–103%.

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Microfabricated Au-Film Sensors for the Voltammetric Determination of Hg(II)

Proceedings ◽

10.3390/proceedings2131518 ◽

2018 ◽

Vol 2 (13) ◽

pp. 1518

Author(s):

Maria Tsetsoni ◽

Eleni Roditi ◽

Christos Kokkinos ◽

Anastasios Economou

Keyword(s):

Electrode Surface ◽

Limit Of Detection ◽

Anodic Stripping Voltammetry ◽

Stripping Voltammetry ◽

Voltammetric Determination ◽

Film Sensor ◽

Au Film ◽

Working Electrode ◽

Anodic Stripping

In this work, a microfabricated Au-film sensor was designed and fabricated for thevoltammmetric determination of Hg(II). The electrode was fabricated on a silicon chip with astandard microengineering approach utilizing photolithography for patterning the electrode shapeand sputtering for deposition of thin Cr and Au films on the surface of the sensors. The sensorswere used for the determination of trace Hg(II) with anodic stripping voltammetry (ASV): initiallyHg(II) in the sample was accumulated on the Au working electrode surface by reduction andformation of an Au(Hg) amalgam followed by oxidation of the preconcentrated metallic Hg using asquare wave voltammetric scan. The limit of detection was 1.5μgL−1 and the coefficient of variationof 10 consecutive measurements was 3.1%.

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Disposable Injection Molded Conductive Electrodes Modified with Antimony Film for the Electrochemical Determination of Trace Pb(II) and Cd(II)

Sensors ◽

10.3390/s19214809 ◽

2019 ◽

Vol 19 (21) ◽

pp. 4809 ◽

Cited By ~ 1

Author(s):

Savvina Christidi ◽

Alexia Chrysostomou ◽

Anastasios Economou ◽

Christos Kokkinos ◽

Peter R. Fielden ◽

...

Keyword(s):

Anodic Stripping Voltammetry ◽

Conductive Polymer ◽

Stripping Voltammetry ◽

Injection Molding Process ◽

Molding Process ◽

Film Sensor ◽

Lake Water Sample ◽

Relative Standard ◽

Antimony Film

This work describes a novel electrochemical sensor fabricated by an injection molding process. This device features a conductive polymer electrode encased in a plastic holder and electroplated in situ with a thin antimony film. The antimony film sensor was applied to the determination of Pb(II) and Cd(II) by anodic stripping voltammetry (ASV). The deposition of Sb on the sensor was studied by cyclic voltammetry (CV) and microscopy. The experimental variables (concentration of the antimony plating solution, deposition potential and time, stripping waveform) were investigated, and the potential interferences were studied and addressed. The limits of detection were 0.95 μg L−1 for Pb(II) and 1.3 for Cd(II) (at 240 s of preconcentration) and the within-sensor percentage relative standard deviations were 4.2% and 4.9%, respectively, at the 25 μg L−1 level (n = 8). Finally, the sensor was applied to the determination of Pb(II) and Cd(II) in a phosphorite sample and a lake water sample.

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