Chemical ionization reaction time-of-flight mass spectrometry: Multi-reagent analysis for determination of trace gas composition

Chemical ionization reaction mass spectrometry (CIRMS) is applied for the first time to a range of organic gases with a variety of functional groups. This technique, recently developed, is an extension to proton transfer reaction-mass spectrometry (PTR-MS) using a greater variety of chemical ionization reagents in the ionization process. Clean sources of the reagents H3O+, NH4+, NO+ and O2+ have been obtained without any mass pre-selection. The reactions of these reagent ions with a range of test VOCs are found to be rapid, with the chemistry generally paralleling that observed previously with selected ion flow tube measurements, although with some important differences. CIRMS is shown to be a more versatile technique than conventional PTR-MS with the potential for rapid multi-reagent analysis of chemical mixtures.