We have deployed an efficient secondary electrospray ionization source coupled to an Orbitrap mass analyzer (SESI-MS) to investigate the emissions of a Begonia Semperflorens. We document how hundreds of species can be tracked with an unparalleled time resolution of 2 min during day-night cycles. To further illustrate the capabilities of this system for volatile organic compounds (VOCs) analysis, we subjected the plant to mechanical damage and monitored its response.
As a result, ~ 1,200 of VOCs were monitored displaying different kinetics. To validate the soundness of our in vivo measurements, we fully characterized some key compounds via MS/MS and confirmed their expected behavior based on prior gas chromatography-mass spectrometry (GC-MS) studies. For example, β-caryophyllene, which is directly related to photosynthesis, was found to show a periodic day-night pattern with highest concentrations during the day. We conclude that the capability of SESI-MS to capture highly dynamic VOC emissions and wide analyte coverage makes it an attractive tool to complement GC-MS in plant studies.