These SPME fiber assemblies can be reused for up to 100 analyses depending on the application.
Higher molecular weight compounds desorb easier from the 7 μm or 30 μm PDMS absorption fiber coatings compared to the 100 μm PDMS or adsorbent fibers. Smaller molecules are retained in the pores of the fibers containing adsorbents in the coating; e.g. Carboxen, divinylbenzene particles.
The SPME fiber is protected by the needle during insertion through the septum and when not exposed for sampling. The original SPME fibers manufactured with 24 gauge needles work very well for manual sampling. SPME fibers with 23 gauge needles and highly recommend the 23 gauge be used for all applications utilising an autosampler.
SPME fibers are coated on a fused silica core and StableFlex SPME fibers have been improved by applying the coating on a flexible fused silica core. The coating partially bonds to the flexible core which results in a more stable coating and a less breakable fiber. The extraction selectivity of StableFlex fibers however may be slightly different from the same coating on a standard fused silica core.