title: Highly porous solid-phase microextraction fiber coating based on poly(ethylene glycol)-modified ormosils synthesized by sol-gel technology.
abstract: The preparation and characteristics of solid-phase microextraction (SPME) fibers coated with Carbowax 20M ormosil (organically modified silica) are described here. Raw fused silica fibers were coated with Carbowax 20M-modified silica using sol-gel process. Scanning electron micrographs of fibers revealed a highly porous, sponge-like coating with an average thickness of (8 +/- 1) microm. The sol-gel Carbowax fibers were compared to commercial fibers coated with 100 microm polydimethylsiloxane (PDMS) and 65 microm Carbowax-divinylbenzene (DVB). Shorter equilibrium times were possible with the sol-gel Carbowax fiber: for headspace extraction of the test analytes, they ranged from less than 3 min for benzene to 15 min for o-xylene. Extraction efficiencies of the sol-gel Carbowax fiber were superior to those of conventional fibers: for o-xylene, the extracted masses were 230 and 540% of that obtained with 100 microm PDMS and 65 microm Carbowax-DVB fibers, respectively.
authors.affiliation: Institute of Chemistry, Campinas State University (Unicamp), CP 6154, 13084-971 Campinas, São Paulo, Brazil.
authors.forename: Raquel Gomes
authors.initials: RG
authors.lastname: da Costa Silva
authors.forename: Fabio
authors.initials: F
authors.lastname: Augusto
mesh_terms: D001554:Benzene / Q000302:isolation & purification; D001555:Benzene Derivatives / Q000302:isolation & purification; D002851:Chromatography, High Pressure Liquid / Q000295:instrumentation*; D004129:Dimethylpolysiloxanes; D005336:Fiber Optic Technology / Q000295:instrumentation; D005782:Gels / Q000737:chemistry; D008832:Microchemistry / Q000379:methods; D008855:Microscopy, Electron, Scanning; D044367:Phase Transition; D011092:Polyethylene Glycols / Q000737:chemistry*; D012828:Silicones; D014050:Toluene / Q000302:isolation & purification; D014753:Vinyl Compounds
chemical_list: D001555:Benzene Derivatives; D004129:Dimethylpolysiloxanes; D005782:Gels; D012828:Silicones; D014753:Vinyl Compounds; D014050:Toluene; D011092:Polyethylene Glycols; C013830:baysilon; C004985:divinyl benzene; D001554:Benzene; C004912:ethylbenzene