Reactions of small hydrocarbons with H 3O +, O 2+ and NO + ions

Abstract

We report selected ion flow tube measurements of reaction rate coefficients and branching ratios for the reactions of H 3O +, O 2 + and NO + with the small hydrocarbons CH 4, C 2H 2, C 2H 4, C 2H 6, C 3H 4 (allene and propyne), C 3H 6, c-C 3H 6, C 3H 8, C 4H 2, C 4H 8 and n, i-C 4H 10. The relevance of these measurements to quantitative selected ion flow tube mass spectrometry (SIFT-MS) is discussed. An application of the measurements is made to the analysis of the chemical species generated by chemical ionization in the exhaust gases from a petrol combustion engine up to m/ z=60. The analysis shows that chemical ionization data are required from more than one precursor ion in order to interpret the data.