Haibo Wang

Over the last 10 years, several solvent-free microextraction techniques for gas chromatography (GC) and mass spectrometry (MS) have been developed. Two of these techniques, solid-phase microextraction (SPME) and stir-bar sorptive extraction (SBSE), are available commercially for the analysis of volatile compounds, such as flavors in foods and beverages, and toxic organic compounds in environmental applications. Other techniques, such as open tubular trapping, inside needle capillary adsorption trap (1), in-tube SPME, capillary microextraction, needle trap, and headspace solid-phase dynamic extraction (2), were also developed for different applications. The basic principle for all of these techniques is essentially the same. Volatile and semivolatile compounds are adsorbed on a sorbent coating, often packed on the interior surface of a capillary column or stainless steel needle. After the sample is concentrated on the coating, the compounds are desorbed thermally in the heated injection port of a gas..

Two of the most commonly occurring unpleasant odor-causing compounds in drinking water are geosmin and 2-methylisoborneol (MIB) (Figure 1). Geosmin is produced primarily by blue-green algae (cyanobacteria) and actinomycete bacteria, and MIB is produced by certain species of cyanobacteria, primarily Oscillatoria. Many environmental laboratories are required to detect these compounds as low as 1–3 ppt concentration and measure quantitatively at 5 ppt.