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A reusable, reagent-less free chlorine sensor using gold thin film electrode
Arif Ul Alam1, Dennis Clyne1, Will Lush2
1Electrical and Computer Engineering, McMaster University, 1280 Main St. W., Hamilton, ON L8S 4 K1, Canada. jamal@mcmaster.ca.
The Analyst
|March 3, 2021
Summary
A novel reusable sensor using a thin gold film accurately measures free chlorine in water without reagents. This advancement is crucial for public health and water safety, especially in resource-limited settings.
Area of Science:
- Electrochemistry
- Materials Science
- Environmental Science
Background:
- Free chlorine is a vital disinfectant in water treatment.
- Accurate monitoring of residual free chlorine is essential for public health.
- Existing methods may require reagents or frequent calibration.
Purpose of the Study:
- To develop a reusable, reagent-less sensor for free chlorine detection.
- To assess the sensor's sensitivity, selectivity, and operational stability.
- To evaluate the sensor's feasibility for practical water quality monitoring.
Main Methods:
- Fabrication of a thin gold film (300 nm) on polyimide tape.
- Design of a simple sensor configuration with a defined sensing area (0.36 cm²).
- Electrochemical characterization of the sensor's performance.
Main Results:
- High sensitivity (0.327 μA ppm⁻¹) and a linear range of 0-6 ppm.
- Excellent accuracy (<0.1 ppm) and selectivity against common interfering ions.
- Stable performance across a pH range of 5.2-8.4 and temperature range of 20-30 °C, with fast response (50 s) and low hysteresis (0.06 ppm).
Conclusions:
- The developed gold thin film sensor offers a reagent-less, accurate, and stable method for free chlorine monitoring.
- Its simple fabrication and ease-of-use support mass production and application in remote areas.
- This sensor technology enhances water safety and public health monitoring capabilities.
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