A Decade with Bismuth-Based Electrodes in Electroanalysis

Voltammetric Behavior of Testosterone on Bismuth Film Electrode: Highly Sensitive Determination in Pharmaceuticals and Human Urine by Square‐Wave Adsorptive Stripping Voltammetry

In this paper, an electrochemical application of bismuth‐film electrode (BiFE) fabricated via ex‐situ electrodeposition onto a glassy carbon electrode for testosterone determination was investigated in aqueous and aqueous/surfactant solutions. In cyclic voltammetry, the compound showed one irreversible and adsorption‐controlled reduction peak. The BiFE revealed good linear response in the examined concentration range of 1 to 45 nmol L−1 testosterone in BrittonRobinson buffer, pH 5.0 containing 3 mmol L−1 cetyltrimethylammonium bromide. The limit of detection was 0.3 nmol L−1 (0.09 ng mL−1). Finally, the BiFE was satisfactorily applied for quantitation of testosterone in both pharmaceutical (oil‐based ampoule) and biological (human urine) samples.

Selective electrochemical determination of trace level copper using a salicylaldehyde azine/MWCNTs/Nafion modified pyrolytic graphite electrode by the anodic stripping voltammetric method

Schematic illustration of Cu²⁺in solution detection using a SA/MWCNTs/Nafion modified PGE.

Ultratrace detection of toxic heavy metal ions found in water bodies using hydroxyapatite supported nanocrystalline ZSM-5 modified electrodes

Hydroxyapatite nanoparticles, intercrystalline mesopores of Ag-Nano-ZSM-5, and lower electron transfer resistance of the material are responsible for high electro-catalytic activity.

Flexible microfabricated film sensors for the in situ quantum dot-based voltammetric detection of DNA hybridization in microwells

A new flexible miniaturized integrated device was microfabricated for the in situ ultrasensitive voltammetric determination of DNA mutation in a microwell format, using quantum dots (QDs) labels. The integrated device consisted of thin Bi, Ag, and Pt films (serving as the working, reference, and counter electrode, respectively) deposited by sputtering on a flexible polyimide substrate. A DNA assay was employed in microwell format, where an immobilized complementary oligonucleotide probe hybridized with the biotinylated target oligonucleotide followed by reaction with streptavidin-conjugated PbS QDs. After the acidic dissolution of the QDs, the flexible sensor was rolled and inserted into the microwell and the Pb(II) released was determined in situ by anodic stripping voltammetry. Since the analysis took place directly in the microwell, the volume of the working solution was only 100 μL and the target DNA could be detected at a concentration down to 1.1 fmol L(-1). The proposed flexible microdevice addresses the restrictions of conventional rigid electrodes while it provides a low cost integrated transducer for the ultrasensitive detection of important biomolecules.

Ultrasensitive and simultaneous detection of heavy metal ions based on three-dimensional graphene-carbon nanotubes hybrid electrode materials

A green and facile method was developed to prepare a novel hybrid nanocomposite that consisted of one-dimensional multi-walled carbon nanotubes (MWCNTs) and two-dimensional graphene oxide (GO) sheets. The as-prepared three-dimensional GO-MWCNTs hybrid nanocomposites exhibit excellent water-solubility owing to the high hydrophilicity of GO components; meanwhile, a certain amount of MWCNTs loaded on the surface of GO sheets through π-π interaction seem to be "dissolved" in water. Moreover, the graphene(G)-MWCNTs nanocomposites with excellent conductivity were obtained conveniently by the direct electrochemical reduction of GO-MWCNTs nanocomposites. Seeing that there is a good synergistic effect between MWCNTs and graphene components in enhancing preconcentration efficiency of metal ions and accelerating electron transfer rate at G-MWCNTs/electrolyte interface, the G-MWCNTs nanocomposites possess fast, simultaneous and sensitive detection performance for trace amounts of heavy metal ions. The electrochemical results demonstrate that the G-MWCNTs nanocomposites can act as a kind of practical sensing material to simultaneously determine Pb(2+) and Cd(2+) ions in terms of anodic stripping voltammetry (ASV). The linear calibration plots for Pb(2+) and Cd(2+) ranged from 0.5 μg L(-1) to 30 μg L(-1). The detection limits were determined to be 0.2 μg L(-1) (S/N=3) for Pb(2+) and 0.1 μg L(-1) (S/N=3) for Cd(2+) in the case of a deposition time of 180 s. It is worth mentioning that the G-MWCNTs modified electrodes were successfully applied to the simultaneous detection of Cd(2+) and Pb(2+) ions in real electroplating effluent samples containing lots of surface active impurities, showing a good application prospect in the determination of trace amounts of heavy metals.

Nano- and micro-hexagons of bismuth on polycrystalline copper: electrodeposition and heavy metal sensing

Tuning the electroreduction of NO₃⁻vis-à-vis Bi³⁺ results in nano-/micro-hexagons. Nanohexagons are highly sensitive to trace detection of lead.

Development of an electrochemically reduced graphene oxide modified disposable bismuth film electrode and its application for stripping analysis of heavy metals in milk

A novel electrochemical sensing platform based on electrochemically reduced graphene oxide film modified screen-printed electrode was developed. This disposable electrode shows excellent conductivity and fast electron transfer kinetics. By in situ plating bismuth film, the developed electrode exhibited well-defined and separate stripping peaks for cadmium and lead. Several parameters, including electrolytes environment and electrodeposition conditions, were carefully optimized to achieve best stripping performance. The linear range for both metal ions at the disposable bismuth film electrode was from 1.0 μg L(-1) to 60.0 μg L(-1). The detection limit was 0.5 μg L(-1) for cadmium ion and 0.8 μg L(-1) for lead ion. Milk sample analysis demonstrates that the developed electrode could be effectively used to detect low levels (μg L(-1)) of cadmium ion and lead ion. Graphene based disposable bismuth film electrode is a sensitive, stable, and reliable sensing platform for heavy metals determination.