Portable oral malodor analyzer using highly sensitive In2O3 gas sensor combined with a simple gas chromatography system Original Research Article

A portable oral malodor analyzer was developed for quantitative detection of volatile sulfur compounds (VSCs) in mouth air using a combination of a semiconductor gas sensor and a compact gas chromatography system. We found that In2O3 doped with Au is the optimum sensing material of the gas sensor for obtaining a high sensitivity to measure all the VSCs in mouth air with low concentration ranges. A specific column design, simple sampling system and signal processing method were applied for achieving a portable analyzer without using a standard pressurized carrier gas. This analyzer can easily measure the concentration of essential components of oral malodor individually and quantitatively over a wide range from 50 to 1000 ppb (v/v).