Background

Elevated fluoride concentrations in drinking water pose a significant risk to human health. The guidelines for drinking water quality issued by the World Health Organization indicate that fluoride concentration of up to 1.5 mg/L is safe to humans (WHO, Guidelines for Drinking Water Quality, Vol 1, 4th ed, 2017). Ingesting water with a fluoride concentration above the guideline could lead to fluorosis, a condition affecting the dental and skeletal systems. In areas where groundwater is the main source of drinking water, over 200 million people are potentially negatively impacted by fluoride that exceeds safe levels in drinking water (S. Jagtap, et al. 2012). Monitoring the fluoride level in drinking water is critical to maintain optimal health. Current technologies for fluoride testing are dominated by colorimetric test kits and ion-selective electrodes (ISE). While they are effective in certain applications, these technologies also come with drawbacks, such as cumbersome setup in remote settings, bulky and costly equipment, measurement errors, costly maintenance, and requirement for safe disposal of wastes due to the use of reagents. For these reasons, there is a need for an easy-to-use, reliable, cost-effective and reagent-free tool to test fluoride levels in remote locations to determine safe drinking water sources.

Technology Overview

Researchers have developed a portable fluoride sensor ( Figure. 1 ) that provides a cost-effective and reagent-free method to detect and measure concentrations of fluoride in drinking water. The sensor employs an optical fiber with aluminum-coated tip. When this aluminum-coated tip is immersed in a fluoride-containing water sample, the coating is removed via the chemical reaction between fluoride and aluminum. Removal of such aluminum coating reduces the intensity of light that reflects from the fiber tip to the photodiode through the optical fiber. The signal associated with this change in light intensity is proportional to the concentration of fluoride, and is translated to fluoride concentration measurement.

Benefits

User-friendly and portable.
Reagent‑free for and environmentally sustainable.
In-situ test results for onsite decision‑making and action.
Ability to gather continuous measurements for monitoring purposes.
Low cost per test.

Applications

Prospecting for good sources of safe drinking water.
In‑situ testing of fluoride levels in water in remote settings.
In‑home monitoring of tap water quality.
Spot check analysis for quality control.

Opportunity

Technology licensing
Research collaboration

Portable Optical Sensor to Measure Fluoride Levels in Water

Patents

IP Status

Seeking