SPME-GC/MS investigations of volatile organic compounds emitted from Australian plants

Identification and quantification of volatile organic compounds (VOCs) emitted by plants is crucial to the understanding of atmospheric processes such as ground level ozone production and aerosol formation. In this paper we discuss in situ measurements of VOCs by Solid Phase Microextraction (SPME) coupled with GS/MS. We present the profiles obtained from some native Australian plants. VOCs have a significant influence on the concentration and distribution of atmospheric trace gases through reactions with radicals such as ‧OH and ‧OOH (HOₓ). By reacting with these radicals they affect the oxidative capacity of the atmosphere. The relative contribution of biogenic and anthropogenic VOCs to the urban atmospheric budget is presently poorly quantified, hence important atmospheric processes are inadequately understood and modelled. SPME is a very simple and efficient sample preparation method that simultaneously extracts and pre-concentrates analytes from the sample matrix. Using head-space analysis of the atmosphere around still functioning plant specimen, emission profiles approaching that of plants in their natural can be obtained. A chamber has been contracted for these in situ analyses, where a portion of the plant is enclosed while leaving the plant undisturbed. This paper describes the optimisation, validation and application of SPME to in situ capture of volatile organic compounds. Some of the plants selected for this analysis are Eucalyptus citriodora, Melaleuca quinquenervia, Melaleuca thymifolia, Backhousia citriodora, Lophostemon confertus, Eucalyptus paniculata and Grevillea robusta. Environmental conditions such as temperature and total photosynthetically available radiation were investigated. Our results are compared tot eh VOC literature and essential oil data.