Experimental device easily measures fluoride in drinking water

Although a certain amount of fluoride is added to municipal water supplies to help prevent tooth decay, too much can actually have the opposite effect – particularly on children. A new device could allow officials to detect those overly-high levels, cheaper and easier than ever before.

Ordinarily, water samples are routinely checked for fluoride content in well-equipped labs. This is an important task, as fluctuating levels of naturally-occurring fluoride can combine with added fluoride to push the total concentration beyond acceptable limits. Unfortunately, though, towns in developing countries often lack such facilities. With that in mind, scientists from Switzerland's EPFL research institute developed a prototype device known as the SION-105.

It's named after a material that it utilizes – which was synthesized by the researchers – that's a type of metal-organic framework (MOF). This means that the material is made up of metal ions connected to organic ligands. And while the MOF is ordinarily luminescent, it darkens when exposed to fluoride ions.

Users add just a few drops of water to the portable device, and then measure the material's brightness. It is claimed that by performing this process, even people with no background in chemistry can quickly determine fluoride levels at a sensitivity of parts-per-million.

In lab tests, the technology was used to assess groundwater samples collected in Vietnam, the United Arab Emirates, and Saudi Arabia. Its readings were found to be very close to those obtained via ion chromatography, which is a standard lab-based method of measuring fluoride content.

"This comparison showcases the performance and reliability of SION-105, which, coupled with the portability and ease-of-use of the device, make it a very user-friendly solution for water sampling in remote areas where frequent fluoride concentration monitoring is paramount," says lead scientist Kyriakos Stylianou.

A paper on the research was recently published in the Journal of the American Chemical Society.

Source: EPFL via EurekAlert