TY - JOUR

T1 - “Green” Three-Electrode Sensors Fabricated by Injection-Moulding for On-Site Stripping Voltammetric Determination of Trace In(III) and Tl(I)

AU - Pitsou, M.

AU - Kokkinos, C.

AU - Economou, A.

AU - Fielden, P.R.

AU - Baldock, S.J.

AU - Goddard, N.J.

PY - 2021/11/3

Y1 - 2021/11/3

N2 - 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%. © 2021 by the authors. Licensee MDPI, Basel, Switzerland.

AB - 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%. © 2021 by the authors. Licensee MDPI, Basel, Switzerland.

KW - Anodic stripping voltammetry

KW - Conductive electrodes

KW - Indium

KW - Injection-moulding

KW - Thallium

U2 - 10.3390/chemosensors9110310

DO - 10.3390/chemosensors9110310

M3 - Journal article

VL - 9

JO - Chemosensors

JF - Chemosensors

SN - 2227-9040

IS - 11

M1 - 310

ER -