A detailed study of the ion chemistry of alkenes focusing on heptenes aimed at their SIFT-MS quantification
Abstract
Analyses of trace amounts of alkene vapours present in exhaled breath are becoming important in clinical research related to inflammatory bowel disease, IBD, currently affecting over 1 million patients in the USA and 2.5 million in Europe. Concentrations of alkenes have been previously found to be different in the breath of IBD patients in comparison with healthy controls and are suggested as potential biomarkers of IBD activity.
Thus, a detailed selected ion flow tube, SIFT, study of the reactions of H3O+, NO+ and O-2(+.) with a homologous series of alkenes (from 1-hexene to 1-decene) and with additional isomers of heptene (trans-2-heptene and a mixture of cis- and trans-3-heptene) has been carried out. The rate coefficients of all primary reactions and product ion branching ratios of the reactions of H3O+ and NO+ ions were obtained, which are necessary for accurate quantification of alkenes by selected ion flow tube mass spectrometry, SIFT-MS.
The results of the present study facilitate analyses of these compounds in real breath samples with the ultimate aim of establishing their clinical use.