Withering of plucked Trachelospermum jasminoides (star jasmine) flowers – Time-dependent volatile compound profile obtained with SPME/GC–MS and proton transfer reaction-mass spectrometry (PTR-MS)

Abstract

In this study, the automated application of proton transfer reaction-mass spectrometry (PTR-MS), SPME/GC–MS (solid phase micro-extraction/gas chromatography-mass spectrometry) and multivariate data analysis (chemometry) to the time-dependent changes of Volatile Organic Compound (VOC) patterns of Trachelospermum jasminoides (T. jasminoides) (star jasmine) flowers are studied. The withering of plucked whole T. jasminoides flowers over a thirteen day range is investigated by monitoring the change of VOC release over time since plucking. Three phases with strong differences in the quantities of VOCs between measurements were seen, with a burst of VOCs at the beginning and at the end of withering. We tentatively identify the most abundant VOCs with PTR-MS, and verify identification with SPME/GC–MS. PTR-MS allows for distinguishing (without identification) 472 peaks from withering T. jasminoides which mostly cannot be found with SPME/GC–MS. A high fragmentation of the compounds is observed. The PTR-MS data are assessed with principal component analysis and the three phases are confirmed. At the beginning, seemingly regular flower VOCs are emitted, while in the third phase of withering, alcohol emission bursts towards the end point of withering. The latter can be only detected with PTR-MS. Hence, PTR-MS and SPME/GC–MS supply complementary information. The study demonstrates the potential of applying PTR-MS together with SPME/GC–MS to time-dependent physiological living flower experiments and of T. jasminoides in particular, and suggests the possible use of PTR-MS fingerprinting for origin determination and quality assessment, and studies such as plant-plant, plant-compound (hormone), plant-animal (pollinator, herbivore) or plant-pathogen interactions.