Submitted to: Insect Pheromones International Symposium Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: April 3, 1998
Publication Date: N/A
Technical Abstract: Solid-phase microextraction (SPME) coupled with gas chromatography (GC) is a valuable new technique for qualitative analysis of airborne organic compounds. It is simple, fast, solventless, and quite sensitive. However, SPME has been used very little for quantitation of headspace volatiles because calibration information has been lacking and because of a bewildering array of experimental parameters. A general method has now been developed that allows the absolute concentration of almost any volatile in a moving air stream to be determined by SPME, with essentially no need for calibration with standards. Previous difficulties with quantitation by SPME are that the sensitivity of SPME varies tremendously among compounds (by over a million-fold in our studies) and that the time required for the SPME fiber to equilibrate with the analyte can vary from seconds to many hours or days. Fortunately, both of these properties are mathematically related to each other and also to other known or easily measured quantities. A single equation (a non-linear regression model) was developed so the concentration in the air can be calculated from the weight of compound absorbed by the SPME fiber (measured simply by GC) and the sampling time. The only other required information is GC retention index (Kovats index) of the compound of interest, knowledge of its functional group, the sampling temperature, the air flow rate, and the diameter of the tubing through which the sample is flowing.