Researchers from Korea have invented a thumb-sized device that can diagnose halitosis by sniffing out the hydrogen sulfide -- the gas that causes the malodor -- from exhaled breath. The device accurately identified bad breath 86% of the time when people blew directly into the device in a study published recently in ACS Nano.
Unlike existing devices that measure small amounts of hydrogen sulfide from exhaled breath that is collected and tested using lab instruments, this is a real-time bad-breath analyzer. The sensor could be incorporated into small devices for quick self-diagnosis of bad breath, the researchers wrote.
The science behind the device is based on previous studies that have shown that when some metal oxides react with sulfur-containing gases, their electrical conductivity changes. Furthermore, pairing metal oxides with noble metal catalysts makes them more sensitive and selective, they wrote.
The researchers mixed sodium chloride and platinum nanoparticles with tungsten and electrically spun the solution into nanofibers that were heated, converting the tungsten into its metal oxide form. Then, they coated interdigitated gold electrodes with the nanofibers and combined the gas sensor with humidity, temperature, and pressure sensors into a small prototype.