Novel anode stripping voltammetric method using electrochemically modified electrodes for arsenic species detection in water
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Date
2024-11-01
Authors
Kashmitha, S. D. S.
Wickramasinghe, N. A.
Wijesinghe, M. B.
Journal Title
Journal ISSN
Volume Title
Publisher
Postgraduate Institute of Science (PGIS), University of Peradeniya, Sri Lanka
Abstract
Arsenic is a heavy metal that is particularly toxic in its inorganic form, As ³ ⁺, and causes health issues in humans, even in trace amounts. Conventional analytical techniques for detecting As ³ ⁺, such as atomic absorption spectroscopy, inductively coupled plasma mass spectrometry, and neutron activation analysis, are not suitable for real-time onsite detection of arsenic in water, which is essential for minimizing arsenic contamination. Recent studies have reported that anodic stripping voltammetry on a modified glassy carbon electrode offers a cheaper and field-portable alternative for detecting trace amounts of As ³ ⁺ in water samples. The drop-casting method was used to modify the bare electrode with AuNPs in such studies. However, the drop-casting method leads to poor reproducibility and high noise levels. Alternatively, this study employed the electrochemical deposition of AuNPs from a solution of 1.00 mM HAuCl₄ in 0.500 M H₂SO₄ by cathodically scanning the potential between +1.0 V and -0.6 V at a scan rate of 50 mV/s under air-saturated conditions. The optimum number of cycles for the electrodeposition was found to be twenty. A detection limit of 0.0625 mM for As ³ ⁺ with an R² value of 0.9847 was obtained through cyclic voltammetric analysis of As ³ ⁺ in 0.500 M H₂SO₄ on the modified electrode. An enhanced detection limit of 100 nM, with an R²value of 0.9723, was achieved using anodic stripping voltammetry. The deposition time and applied voltage for the anodic stripping analysis were optimized to 1200 s and -0.4 V, respectively. Future studies will focus on analysing water and soil samples using the newly developed method.
Description
Keywords
Anodic stripping voltammetry , Arsenic , Electrodeposition , Gold nanoparticles , Modified glassy carbon electrode
Citation
Proceedings of the Postgraduate Institute of Science Research Congress (RESCON) -2024, University of Peradeniya, P 40