Abstract for presentation at 14th IUAPPA World Congress

Selected Ion Flow Tube Mass Spectrometry (SIFT-MS) detects and quantifies volatile organic compounds (VOCs) from whole air in real time to very low part-per-billion (ppb) concentrations (by volume). In this paper, SIFT-MS was used to detect and quantify a range of important atmospheric pollutants (benzene and other aromatics, 1,3-butadiene, formaldehyde, and acetaldehyde) derived primarily from the combustion of petroleum fuels.
SIFT-MS detects trace VOCs in the presence of the bulk components of air by utilising very well characterised gas-phase reactions of the soft chemical ionisation agents, H3O+, NO+ and O2+. The reaction conditions are precisely controlled in the flow tube enabling VOCs to not only be detected in real time but also quantified absolutely based on their known ion products and reaction rate coefficient. The use of several chemical ionisation agents provides up to three individual quantitative measurements of each target compound, greatly reducing interference effects compared to other real-time technologies.
Standard atmospheres of the target compounds were generated using NIST-traceable permeation tubes and gas standards. Static dilutions were prepared from these standard atmospheres demonstrating detection and quantification at the very low levels required for ambient air monitoring. The analytical method was then applied to the real-time measurement of ambient air at the Syft Technologies laboratory.
Detection of the target compounds at concentrations pertinent to ambient air monitoring is demonstrated, under both the controlled conditions of an analytical laboratory and the less controlled conditions of environmental monitoring.