Ammonia breath analysis

Abstract

Breath analysis is an important emerging non-invasive tool for the diagnosis and monitoring of diseases because it can provide information about a vast array of biochemical processes occurring in the human body. Out of the thousands of compounds present in a breath sample, ammonia is of particular interest because of its link to a range of gastric, renal, hepatic, and pulmonary conditions. This review provides an introduction to human breath analysis with a focus on ammonia. The main analytical methods for the analysis of ammonia in breath are then covered with a particular focus on chemical sensing methods and their advantages over more established methods, for example those based on mass spectrometry or animal olfaction. The use of chemical sensors for breath analysis is promising because these sensors are small scale, relatively cheap and easy to use, and are therefore suitable for integration into point-of-care breath analysis devices. Although some chemical sensor-based devices for breath analysis are now being commercialised, challenges remain that are related to selectivity, sensitivity, stability, and the influence of humidity on the sensors.