Abstract

Quantification of Volatile Metabolites in Exhaled Breath and Biological Fluids by SIFT-MS in Support of Clinical Diagnosis

David Smith, Professor, Keele University

The major features of the selected ion flow tube mass spectrometry (SIFT-MS) analytical method and its unique analytical capability for trace gas ambient analysis are stressed, which allow quantification of volatile organic and inorganic compounds directly from the measurement of physical parameters obviating regular instrumental calibration using internal or external standards. Emphasis is placed on the challenging real-time accurate analysis of single exhalations of humid exhaled breath. The quality of the data that can be obtained by SIFT-MS is illustrated by the quantification of some exhaled breath metabolites that are of immediate relevance to physiology and medicine, including that of hydrogen cyanide in the breath of patients with cystic fibrosis, elevated breath pentane in inflammatory bowel disease, the contentious connection between breath acetone and diabetes and the determination of total body water in patients with chronic kidney disease. Studies of the generation of volatile biomarkers by in vitro cultures of some respiratory malignant/non-malignant mammalian cells, and bacterial and fungal cells are providing the stimulus for further investigations of potential breath biomarkers for respiratory infection.