An international team of researchers from Korea and the United States has constructed a tiny portable device that directly detects hydrogen sulfide (H2S) in human breath.
Continuous monitoring of hydrogen sulfide in human breath for early stage diagnosis of halitosis is of great significance for prevention of dental diseases. Image credit: Shin et al., doi: 10.1021/acsnano.1c01350.
No one wants bad breath — not when visiting friends and family, at a job interview, and especially not on a first date.
Smelly breath can make things awkward, but it also is a natural warning sign, indicating that serious dental issues are occurring.
Some devices measure small amounts of stinky hydrogen sulfide, but they require exhaled air to be collected and tested on expensive instruments in a lab, which is not feasible for consumers.
Previous studies have shown that when some metal oxides react with sulfur-containing gases, their electrical conductivity changes.
And when metal oxides are paired with noble metal catalysts, they can become more sensitive and selective.
To develop a small, real-time analyzer, Dr. Il-Doo Kim from the Korea Advanced Institute of Science and Technology, Dr. Kak Namkoong from the Samsung Advanced Institute of Technology and their colleagues wanted to find the right combination of substances that would elicit the fastest and strongest response to hydrogen sulfide in air blown directly onto it.
They mixed sodium chloride and platinum nanoparticles with tungsten, and electrospun the solution into nanofibers that they heated, converting the tungsten into its metal oxide form.
In preliminary tests, the composite made from equal parts of each metal had the largest reactivity to hydrogen