Solid-phase microextraction fiber type

Although liquid injection is the usual method of sample introduction, there are other types of injector available. Techniques include headspace analysis for species with low molecular masses and high volatility, such as halocarbons in water thermal desorption for analytes (e.g., pheromones) trapped by passage through a cartridge packed with a retentive material such as Tenax and solid phase microextraction fiber elution for compounds that have been adsorbed onto the fiber from liquid or gaseous matrices. 

Arthur and Pawliszyn introduced solid-phase microextraction (SPME) in 1990 as a solvent-free sampling technique that reduces the steps of extraction, cleanup, and concentration to a unique step. SPME utilizes a small segment of fused-silica fiber coated with a polymeric phase to extract the analytes from the sample and to introduce them into a chromatographic system. Initially, SPME was used to analyze pollutants in water - via direct extraction. Subsequently, SPME was applied to more complex matrixes, such as solid samples or biological fluids. With these types of samples, direct SPME is not recommended nevertheless, the headspace mode (HSSPME) is an effective alternative to extracting volatile and semivolatile compounds from complex matrixes. (Adapted from Llompart et ah, 2001)... 

Other innovations include PLE, MAE (see Section 1.3.1), and solid-phase microextraction (SPME). SPME is a sampling method applied to GC, HPLC, and CE. It is based on adsorbent- or adsorbent-type fibers and lends itself well to miniaturization. ... 

Figure 5.9 Comparison between GC-MS analysis of 3-mercaptohexan-l-ol (3-MH) and 3-mercaptohexanol acetate (3-MHA) in wine by HS-SPME without on-fiber derivatisation and by SPE using ENV+-type resin enrichment. (From Gas Chromatography-Mass Spectrometry determination of 3-mercaptohexan-l-ol and 3-mercaptohexyl acetate in wine. A comparison between Solid Phase Extraction and Headspace Solid Phase Microextraction methods, Fedrizzi et al., 2007b, Anal. Chim. Acta, 596(2), 291-297)...

Popp, P. and Paschke, A., Efficiency of direct solid-phase microextraction from water — comparison of different types of fibers including new C8-coating, Chromatogr. A, 49(11-12), 686-690, 1999. Pons, B., Fernandez Torroba, M. A., Ortiz, G., and Tena, M. T., Monitoring and evolution of the pollution by VOCs in the groundwater of the Najeriha river basin (Spain), Int. J. Environ. Anal. Chem., 83(6), 495-506, 2003. 

As described earlier (4,5), we have studied nestmate recognition by examining the differences of cuticular hydrocarbons between species, colonies, and castes. Briefly, we developed a methodology for the extraction of termite cuticular hydrocarbons by solid phase microextraction (SPME). Both headspace SPME, where the termites were heated in a vial to 120 °C with the fiber 1 cm above the termites, and direct contact SPME, where live termites walked on the SPME fiber for a certain time period, were studied. As shown in Figure 1, both methods were comparable to the normal hexane extraction method in the types of cuticular hydrocarbons that were extracted. Since SPME requires less manipulation of the sample and may use living termites, it may have advantages. 

The solid-phase microextraction device (SPME) was purchased from Supelco Co. (Bellefonte, PA). The following types of SPME fiber were used polydimethylsiloxane (PDMS) with lOO-pm thickness, PDMS/ divinylbenzene (DVB) with 65-pm thickness, and Carboxen (Supelco Co., Bellefonte, PA, U.S.A.)/PDMS (CAR/PDMS) with 75-pm thickness. 

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