Direct arsenic(III) sensing by a renewable gold plated Ir-based microelectrode

Area of Science:

• Environmental Chemistry
• Electrochemistry
• Analytical Chemistry

Background:

• Arsenic(III) detection in natural waters is crucial for environmental and health assessments.
• Existing methods face challenges with sensitivity, robustness, and field applicability.
• Electrochemical techniques offer potential for sensitive and on-site arsenic analysis.

Purpose of the Study:

• To develop a microelectrode for sensitive, field-deployable detection of arsenic(III) in aquatic systems.
• To introduce a gold-plated iridium microelectrode (Au-IrM) with a renewable gold layer.
• To evaluate the sensor's performance at natural pH and low concentrations.

Main Methods:

• Fabrication of a gold-plated iridium microelectrode (Au-IrM).
• Electrochemical characterization using Square Wave Anodic Stripping Voltammetry (SWASV).
• Testing with varying arsenic(III) concentrations and preconcentration times at pH 8.

Main Results:

• Reproducible linear calibration curves for arsenic(III) from 1 to 50 nM.
• Negligible interference from copper and chloride ions at typical environmental concentrations.
• The gold layer demonstrated a 7-day lifetime with good reproducibility (RSD < 12.5%).

Conclusions:

• The Au-IrM sensor is suitable for nanomolar arsenic(III) determination in natural waters.
• The renewable gold layer enhances sensor robustness for field applications.
• This work supports the development of gel-integrated electrochemical sensors for arsenic detection.