Related Experiment Video
Updated: Jul 13, 2026

Measurement of Extracellular Ion Fluxes Using the Ion-selective Self-referencing Microelectrode Technique
Published on: May 3, 2015
Voltammetric and reference microelectrodes with integrated microchannels for flow through microvoltammetry. 1. The
1CABE, Department of Inorganic, Analytical and Applied Chemistry, Sciences II, Geneva University, Switzerland.
Abstract:
This paper describes the construction of 2 microsensor units for on-line voltammetric detection inside a cylindrical microcell (a working microsensor unit and a reference and auxiliary microsensor unit), for application to heavy-metal analysis in complex media such as natural waters. Both microsensor units include a channel for the solution renewal in the microcell after analysis. The working microsensor, a Hg-plated Ir microelectrode, is protected against fouling with an agarose gel including a hydrophobic chromatographic phase (C18). The fabrication steps and the quality tests related to long-term use and reliability, as well as to precision, are described. The application of the protective gel layer against fouling by hydrophobic or surface active small molecules is of general application, reliable, and very efficient. The reference and auxiliary unit is composed by an iridium oxide based mini reference electrode, an auxiliary Pt electrode, and a circulation channel. It is built to enable its use inside a 700-microm-diameter tubing connected to a hollow fiber supported liquid membrane lumen (volume, 5-10 microL) for heavy-metal analysis. However, it can be used in any other microanalytical system. The reference electrode is sufficiently stable for voltammetric applications (1-2 mV drift/day), and its lifetime is more than one year. The Ti/IrO2 core is immersed in a pH-buffered agarose gel, to guarantee potential stability even when the electrode is immersed in variable pH solutions.
More Related Videos
Related Concept Videos
Electrodes: Overview
There are two main types of electrodes in electrochemical cells. The first type, known as the working or indicator electrode, has a potential that is sensitive to the analyte's concentration and reacts to changes in the...
Interfacial Electrochemical Methods: Overview
Potentiometry: Types of Electrodes
The Standard Hydrogen Electrode (SHE) is a widely used reference electrode that maintains zero potential across all temperatures. However, its need for a continuous hydrogen gas supply renders it impractical for everyday use.
An alternative to SHE is the Saturated Calomel Electrode (SCE). This electrode features an...
Potentiometry: Membrane Electrodes
Voltammetry: Overview
A voltammetric cell uses three electrodes: a working electrode, a reference electrode, and an auxiliary electrode. The redox reactions occur in the working...
Voltammetric Techniques: Pulse Voltammetry

