Carbonyl sulfide detection with a thermoelectrically cooled midinfrared quantum cascade laser

Abstract

A compact absorption spectrometer with a midinfrared tunable quantum cascade laser operating at 4.86 microm (2054 cm(-1)) is used to measure lower concentrations of carbonyl sulfide (COS) in air. A detection sensitivity of approximately 30 parts in 10(9) of COS and the selectivity of two stable isotopes, 12C(16)O32S and 12C(16)O34S, are demonstrated. Specifically, the feasibility of detecting COS in expired human breath as a potential noninvasive medical diagnostic tool is investigated.