In the few years since it’s introduction, solid phase microextraction (SPME*) has become a practical alternative for sample preparation for gas-chromatography. SPME reduces the time required for sample preparation and eliminates the use of large volumes of extraction solvents. In SPME, analytes establish an equilibrium among the sample matrix, the headspace above the sample and a stationary phase coated on a fused silica fiber. The adsorbed compounds are thermally desorbed from the fiber to a capillary GC column. Because no solvent is injected and the analytes are rapidly desorbed onto the column, minimum detection limits are improved and resolution is maintained. SPME is useful in many different analysis, including characterization of environmental, forensic, food/flavor and pharmaceutical compounds.
The PAL COMBI-xt provides a fully automated SPME sample preparation process. All movements of the SPME fiber from precondition, adsorption and desorption are precisely controlled for optimum performance. Prior and during extraction the samples can be shaked and heated, which dramatically reduces analysis time for semivolatile compounds. Variable vial penetration depth allows to extract the compounds in liquid samples itself or in the headspace area above liquid/solid samples. After the compounds are thermally desorbed in the hot GC injector, the fiber may be fully cleaned again in a special heated and purged Fiber Conditioning Station.
*Solid Phase Microextraction (SPME) Technology licensed exclusively to Supelco Inc.