An improved bonded-polydimethylsiloxane solid-phase microextraction fiber obtained by a sol-gel/silica particle blend

A novel procedure for solid-phase microextraction fiber preparation is presented, which combines the use of a rigid titanium alloy wire as a substrate with a blend of PDMS sol-gel mixture/silica particles, as a way of increasing both the mechanical robustness and the extracting capability of the sol-gel fibers. The approximately 30 microm average thick fibers displayed an improvement in the extraction capacity as compared to the previous sol-gel PDMS fibers, due to a greater load of stable covalently bonded sol-gel PDMS. The observed extraction capacity was comparable to that of 100 microm non-bonded PDMS fiber, having in this case the advantages of the superior robustness and stability conferred, respectively, by the unbreakable substrate and the sol-gel intrinsic characteristics. Repeatability (n=3) ranged 1-8% while fiber production reproducibility (n=3) ranged 15-25%. The presence of the silica particles was found to have no direct influence on the kinetics and mechanism of the extraction process, thus being possible to consider the new procedure as a refinement of the previous ones. The applicability potential of the devised fiber was illustrated with the analysis of gasoline under the context of arson samples.