title: Solid-phase microextraction Ni-Ti fibers coated with functionalised silica particles immobilized in a sol-gel matrix.
abstract: One of the possible approaches for the development of novel solid-phase microextraction (SPME) fibers is the physical deposition of porous materials onto a support using high-temperature epoxy glue. However, a major drawback arises from decomposition of epoxy glue at temperatures below 300 degrees C and instability in some organic solvents. This limitation motivated us to explore the possibility of replacing the epoxy glue with a sol-gel film, thermally more stable and resistant to organic solvents. We found that functionalised silica particles could be successfully attached to a robust Ni-Ti wire by using a UV-curable sol-gel film. The particles were found to be more important than the sol-gel layer during the microextraction process, as shown by competitive extraction trials and by the different extraction profiles observed with differently functionalised particles. If a quality control microscopic-check aiming at the rejection of fibers exhibiting unacceptably low particle load was conducted, acceptable (6-14%) reproducibility of preparation of C(18)-silica fibers was observed, and a strong indication of the durability of the fibers was also obtained. A cyclohexyldiol-silica fiber was used, as a simple example of applicability, for the successful determination of benzaldehyde, acetophenone and dimethylphenol at trace level in spiked tap water. Recoveries: 95-109%; limits of detection: 2-7 microg/L; no competition effects within the studied range (<or=125 microg/L).
authors.affiliation: Department of Chemistry, Faculty of Science, University of Porto, CIQ-UP, Porto, Portugal. mazenha@fc.up.pt
authors.forename: Manuel
authors.initials: M
authors.lastname: Azenha
authors.forename: Mariana
authors.initials: M
authors.lastname: Ornelas
authors.forename: A
authors.initials: A
authors.lastname: Fernando Silva
mesh_terms: D000098:Acetophenones / Q000032:analysis; D000497:Alloys / Q000737:chemistry*; D001547:Benzaldehydes / Q000032:analysis; D002138:Calibration; D002849:Chromatography, Gas; D008855:Microscopy, Electron, Scanning; D009532:Nickel / Q000737:chemistry*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012822:Silicon Dioxide / Q000737:chemistry*; D052617:Solid Phase Microextraction / Q000379:methods*; D014025:Titanium / Q000737:chemistry*; D014466:Ultraviolet Rays; D014867:Water / Q000737:chemistry
chemical_list: D000098:Acetophenones; D000497:Alloys; D001547:Benzaldehydes; D014867:Water; D012822:Silicon Dioxide; D009532:Nickel; D014025:Titanium; C038699:acetophenone; C032175:benzaldehyde