2P-41 PDF
Calculation of the sensitivity of proton-transfer-reaction mass spectrometry (PTR-MS) for volatile organic compounds using molecular properties
Proton-transfer-reaction mass spectrometry (PTR-MS) allows the detection of a large number of trace gases in air through proton-transfer reaction with H3O+ reagent ions. Measurement sensitivities can be experimentally determined using calibration gases or calculated using the rate constant for the proton-transfer reaction, but rate constants have only been measured for a subset of compounds. Here we show that capture collision rate constants for proton-transfer reactions of H3O+ with various different volatile organic compounds (VOCs) can be obtained using the molecular mass, elemental composition, and functionality of VOCs. This methodology makes it possible to comprehensively and accurately calculate the sensitivities of atmospherically important VOCs measured by PTR-MS.