PROTON-TRANSFER REACTION MASS-SPECTROMETRY - ONLINE TRACE GAS-ANALYSIS AT THE PPB LEVEL

A system for trace gas analysis using proton transfer reaction mass spectrometry (PTR-MS) has been developed which allows for on-line measurements of components with concentrations as low as 1 ppb. The method is based on reactions of H(3)O(+) ions, which perform non-dissociative proton transfer to most of the common organic trace constituents but do not react with any of the components present in clean air. Examples of analysis of breath taken from smokers and non-smokers as well as from patients suffering from cirrhosis of the liver, and of air in buildings as well as of ambient air taken at a road crossing demonstrate the wide range of applicability of this method. An enhanced level of acetonitrile in the breath is a most suitable indicator that a person is a smoker. Enhanced levels of propanol strongly indicate that a person has a severe liver deficiency.