Proton transfer reaction-mass spectrometry as a technique to measure volatile emissions of Muscodor albus

Muscodor albus is an endophytic fungus that produces volatile organic compounds (VOCs) that both inhibit and kill other microorganisms. This fungus is now being used to treat human wastes and disinfest soils of plant disease causing organisms. The development of a method to accurately determine the quantity and quality of volatiles being emitted by this organism is critical for optimizing its application as an antimicrobial agent. Proton transfer reaction-mass spectrometry (PTR-MS) was used to monitor the concentration of VOCs emitted by M. albus. This on-line technique is fast, accurate and provides data at the detection limits of ppb. Production of VOCs is temperature dependent with decreased gas production occurring at higher temperatures. The technique was also applied to soils containing M. albus along with the plant pathogen Pythium ultimum and it was possible to successfully monitor VOC production in situ.