SPME-OC Fiber Assembly, Polydimethylsiloxane/Divinylbenzene (PDMS/DVB)

A new development in SPME fiber technology incorporates a protective overcoating on the fiber. This overcoating, which consists of polydimethylsiloxane (PDMS) serves as a barrier to protect the fiber from the matrix, which makes it more physically robust and less prone to chemical fouling. High background samples, such as many foods, pose a challenge to immersion SPME due to the presence of fats, sugars, pigments, and other macromolecules. These can stick to the SPME fiber and reduce its usable life and/or be transferred to the GC, where they may interfere with chromatographic analysis. Overcoating the fiber with PDMS reduces these problems.