We demonstrate that the concentration of a red blood cell solution under physiological conditions can be determined by electrochemical voltammetry. The magnitude of the oxygen reduction currents produced at an edge-plane pyrolytic graphite electrode was diagnosed analytically at concentrations suitable for a point-of-care test device. The currents could be further enhanced when the solution of red blood cells was exposed to hydrogen peroxide. We show that the enhanced signal can be used to detect red blood cells at a single entity level. The method presented relies on the catalytic activity of red blood cells towards hydrogen peroxide and on surface-induced haemolysis. Each single cell activity is expressed as current spikes decaying within a few seconds back to the background current. The frequency of such current spikes is proportional to the concentration of cells in solution.

Ultratrace levels of Hg have been quantified by undertaking linear sweep voltammetry with a silver nanoparticle-modified glassy carbon electrode (AgNP-GCE) in aqueous solutions containing Hg. This is achieved by monitoring the change in the silver stripping peak with Hg concentration resulting from the galvanic displacement of silver by mercury: Ag(np) + 1/2Hg(aq) → Ag(aq) + 1/2Hg(l). This facile and reproducible detection method exhibits an excellent linear dynamic range of 100.0 pM to 10.0 nM Hg concentration with R = 0.982. The limit of detection (LoD) based on 3σ is 28 pM Hg, while the lowest detectable level for quantification purposes is 100.0 pM. This method is appropriate for routine environmental monitoring and drinking water quality assessment since the guideline value set by the US Environmental Protection Agency (EPA) for inorganic mercury in drinking water is 0.002 mg L (10 nM).

Oxidation and reduction of the oxide ions in the bulk of cathode materials is a potential route towards increasing the energy density of Li-ion batteries. Here, we present neutron PDF...

The contamination of drinking water and food products by aluminium represents a serious health issue, as it is associated with chronic neurodegenerative diseases. Herein we report an analytical electrochemical method for the determination of aluminium(III) at glassy carbon electrodes, modified with commercially available tannic acid-capped gold nanoparticles. The combination of gold nanoparticles and tannic acid as capping/chelating agent results in an accurate and sensitive detection of aluminium(III) in aqueous solutions by square wave voltammetry (SWV). Employing the presented methodology, clear measurable signals are seen even at the low limit of 10.0 pM, markedly and usefully lower than the permissible level of 7.4 µM for drinking water as defined by the WHO and which compares favourably with alternative detection methods.

Particle‐impact electrochemistry is employed to study spherical polyethylene microparticles suspended in an aqueous solution. This electrochemical method detects polyethylene microparticles impacting on a carbon fiber electrode generating a transient current response or “spike”. We interpret the physio‐chemical origin of the spikes and accurately identify particle size distributions and concentrations for microparticles of sizes 1–10 μm.