Sensing performance of thermoelectric hydrogen sensor for breath hydrogen analysis

We studied the sensing performance of the thermoelectric hydrogen sensor (THS) aimed at application to the human breath hydrogen (H2) analysis for the evaluation of colonic flora. The THS has unique gas sensing performance such as H2 selectivity and immunity to humidity. We have designed a simple human breath analysis system with this sensor, gas pump and dehumidifier of silica gel. The humidity of the human breath gas was controlled to be as low as 20% RH at 25 °C through the gas-drying tube because the humidity in the human breath gas causes serious noise effect. The THS system was able to detect 4–103 ppm of H2 in human breath sample which coexisted with various gases such as methane (CH4) and carbon monoxide (CO).