Selection Guide for Supelco SPME Fibers

Selection Tips & Typical Applications

In SPME, you can adsorb analytes from a liquid sample, by immersion or headspace extraction, or a solid sample, by headspace extraction, using a polymer-coated fused silica fiber. Analytes are desorbed from the fiber by exposing the fiber in the injection port of a GC or in the desorption chamber of an SPME/ HPLC interface.

Determine the type of fiber you need according to the molecular weights and polarity of the analytes.

• Low molecular weight or volatile compounds usually require a 100µM polydimethylsiloxane (PDMS)-coated fiber.
• Larger molecular weight or semivolatile compounds are more effectively extracted with a 30µM PDMS fiber or a 7µM PDMS fiber.
• To extract very polar analytes from polar samples, use an 85µM polyacrylate-coated fiber.
• More volatile polar analytes, such as alcohols or amines, are adsorbed more efficiently and released faster with a 65µM polydimethylsiloxane/ divinylbenzene (PDMS/DVB)-coated fiber.
• A 60µM PDMS/DVB fiber is a general purpose fiber for HPLC.
• For trace-level volatiles analysis, use a 75µM PDMS/ Carboxen fiber.
• For an expanded range of analytes (C3-C20), use a 50/30 divinylbenzene/ Carboxen on PDMS fiber.

Most of these fibers are compatible with HPLC solvents, but the 100µM and 30µM PDMS-coated fibers cannot be used with hexane. SPME fiber holders are available in two versions, one for manual use and one for use with autosamplers or with our SPME/HPLC interface. Both versions include the following features:

• A handtight needle hub assembly for quick interchange of fibers.
• A window in the barrel, to identify the fiber by its color-coded hub.

The manual holder has an adjustable needle gauge that controls the depth of fiber introduction into the sample vial or injection port. A spring retracts the fiber into the protective needle and a locking mechanism secures the fiber in the exposed position during extraction or desorption.

The automated holder is similar in design to the manual version. The autosampler controls fiber movement, allowing automatic sample extraction. The automated holder also is required for use with an SPME/ HPLC interface.

A specialized type of manual SPME holder, the SPME portable sampler, allows you to concentrate organics from air or water, in the field, then store them for transport to the laboratory.

Some typical applications for SPME are:

• Environmental analyses of water samples
• Headspace analysis of trace impurities in polymers and solid samples
• ppt odor analyses
• Flavor analyses of food products
• Forensic analyses of arson/explosives samples
• Toxicology analyses: blood alcohol or drugs in urine/serum
• Surfactants, other industrial applications