Quantum-cascade-laser-based optoacoustic sensors for breath test applications

To date, researchers have identified over 400 different compounds contained in human breath, some of which are present at parts per billion (ppb) or even parts per trillion (ppt) concentration levels [1,2]. These molecules have both endogenous and exogenous origins and provide information about physiological processes occurring in the body as well as environmental exposure or absorption of contaminants. Therefore, a breath test is becoming increasingly important as a non-invasive procedure for clinical diagnostics . Development of trace gas sensor technologies is a key factor in the advancement of breath analysis. Small, affordable, easy-to-use, sensitive and accurate techniques are needed for the detection of breath compounds. Ideally, exhaled molecules can be quantified in realtime using a hand-held device.