A New Approach for Monitoring Sweat Ammonia Levels Using a Ventilated Capsule

Ammonium levels in sweat can potentially be used to measure muscle fatigue and to diagnose particular metabolic myopathies. To research the potential use of ammonia in sweat as a biomarker, a new real-time monitoring system is developed. This system consists of a capsule that is placed on the skin and ventilated with dry air. A metal-oxide gas sensor in the capsule detects the ammonia that is evaporated from sweat. The sensor system was built, and calibration experiments were performed. The sensors show good sensitivity from 27 mV/ppm to 1.1 mV/ppm in the desired measurement range of 1 to 30 ppm, respectively. A temperature and humidity sensor is integrated to compensate for temperature and humidity effects on the NH3 sensor.

Design and Simulation of Metal Oxide Gas Sensor for Breath Analyzer Application

Metal oxide semiconductor has been widely used for breath analyzer applications. In this work, Acetone gas is the target gas as it an important breath marker for diabetes disease. Among the different p-type metal oxide nanostructures, Nickel oxide nanospheres are used as the sensing material as it is a promising candidate for Acetone sensing. The variation of resistance of the sensing material with the concentration of the target gas was analyzed. As Acetone is a reducing gas, the resistance of the sensing layer was found to increase when the sensing layer was exposed to the target gas. The simulation was done using COMSOL Multiphysics.