Vibrating screen printed electrode of gold nanoparticle-modified carbon nanotubes for the determination of arsenic(III)

Advances in Electrochemical Detection Electrodes for As(III)

Arsenic is extremely abundant in the Earth's crust and is one of the most common environmental pollutants in nature. In the natural water environment and surface soil, arsenic exists mainly in the form of trivalent arsenite (As(III)) and pentavalent arsenate (As(V)) ions, and its toxicity can be a serious threat to human health. In order to manage the increasingly serious arsenic pollution in the living environment and maintain a healthy and beautiful ecosystem for human beings, it is urgent to conduct research on an efficient sensing method suitable for the detection of As(III) ions. Electrochemical sensing has the advantages of simple instrumentation, high sensitivity, good selectivity, portability, and the ability to be analyzed on site. This paper reviews various electrode systems developed in recent years based on nanomaterials such as noble metals, bimetals, other metals and their compounds, carbon nano, and biomolecules, with a focus on electrodes modified with noble metal and metal compound nanomaterials, and evaluates their performance for the detection of arsenic. They have great potential for achieving the rapid detection of arsenic due to their excellent sensitivity and strong interference immunity. In addition, this paper discusses the relatively rare application of silicon and its compounds as well as novel polymers in achieving arsenic detection, which provides new ideas for investigating novel nanomaterial sensing. We hope that this review will further advance the research progress of high-performance arsenic sensors based on novel nanomaterials.

Development and Characterization of Novel Flow Injection, Thin-Layer, and Batch Cells for Electroanalytical Applications Using Screen-Printed Electrodes

In the present paper, the design, fabrication, and analytical applications of three novel cells for flow injection, thin-layer, and batch electrochemical measurements using screen-printed electrode chips (SPECs) are described. Each cell consisted of an acrylic base and a transparent acrylic cover. The essential construction feature of each cell base was a cavity to accommodate the SPEC, whereas the construction features of the clear acrylic cover determined the cell shape and its function. The presented cells offered several common advantages, which include (i) convenient electrical connection of the SPEC to any potentiostat without the need for special cables, (ii) the SPEC was completely contained within the cell body, which eliminated the risk of its breakage, (iii) suitable for use with a large number of commercially available SPECs, and (iv) excellent SPEC sealing. The flow cell offered additional advantages of convenient customization of the cell dead volume and convenient visual inspection of the surface and the vicinity of SPEs. The presented thin-layer cell is the first report on a dedicated cell which realized a near-ideal thin-layer steady-state voltammetry using SPECs. The universal batch cell (UBC) offered extreme versatility and proved suitable for all batch applications in sample volumes ranging from 25 μL to 40 mL with an optional controlled temperature and atmosphere. Moreover, a novel way to achieve stirred-solution chronoamperometry and hydrodynamic voltammetry using SPECs (with superior signal-to-noise ratios) using the UBC is described. Electrochemical measurements to demonstrate the merits and the applicability of all cells are also presented.

Fiber optic surface-plasmon-resonance-based highly sensitive arsenic sensor prepared using α-Fe2O3/SnO2 core-shell nanostructure with optimized probe parameters

A novel surface plasmon resonance (SPR)-based fiber optic arsenic [As (III)] sensor is presented using α-Fe₂O₃/SnO₂ core-shell nanostructure [abbreviated as (α-Fe/Sn) CS] synthesized using hydrolysis. Due to its extraordinary properties, such as very large surface area, great adsorption capabilities, and chemical reactivity, α-Fe₂O₃ nanoparticles offer excellent sensitivity and selectivity for As (III), while SnO₂ shows great catalytic properties. To achieve the best sensing performance, the (α-Fe/Sn) CS is synthesized at different temperatures, and its morphological study is carried out using transmission electron microscopy. The performance of the probe fabricated over the silver-coated unclad core of the fiber with optimized fabrication temperature and attachment time of (α-Fe/Sn) CS is investigated for 0-100 μg/L concentration of As (III). The sensor possesses the limit of detection of 0.47 μg/L. Further, the roles of common interferands in sensor performance are investigated. The sensor possesses the advantages of real-time detection, capability of remote sensing, and online monitoring, which uphold its industrial application.

Screen-Printed Electrodes Modified with "Green" Metals for Electrochemical Stripping Analysis of Toxic Elements

This work reviews the field of screen-printed electrodes (SPEs) modified with “green” metals for electrochemical stripping analysis of toxic elements. Electrochemical stripping analysis has been established as a useful trace analysis technique offering many advantages compared to competing optical techniques. Although mercury has been the preferred electrode material for stripping analysis, the toxicity of mercury and the associated legal requirements in its use and disposal have prompted research towards the development of “green” metals as alternative electrode materials. When combined with the screen-printing technology, such environment-friendly metals can lead to disposable sensors for trace metal analysis with excellent operational characteristics. This review focuses on SPEs modified with Au, Bi, Sb, and Sn for stripping analysis of toxic elements. Different modification approaches (electroplating, bulk modification, use of metal precursors, microengineering techniques) are considered and representative applications are described. A developing related field, namely biosensing based on stripping analysis of metallic nanoprobe labels, is also briefly mentioned.

Recent Advances in the Fabrication and Application of Screen-Printed Electrochemical (Bio)Sensors Based on Carbon Materials for Biomedical, Agri-Food and Environmental Analyses

This review describes recent advances in the fabrication of electrochemical (bio)sensors based on screen-printing technology involving carbon materials and their application in biomedical, agri-food and environmental analyses. It will focus on the various strategies employed in the fabrication of screen-printed (bio)sensors, together with their performance characteristics; the application of these devices for the measurement of selected naturally occurring biomolecules, environmental pollutants and toxins will be discussed.