title: Sol-gel molecular imprinted ormosil for solid-phase extraction of methylxanthines.
abstract: A organically modified molecularly imprinted silica (MIS), selective for methylxanthines, was prepared using a simple sol-gel procedure. Caffeine was used as template; 3-aminopropyltrimethoxysilane (APTMS) as functional monomer and tetraethyl orthosilicate (TEOS) as reticulating agent. The material was packed on solid-phase extraction (SPE) cartridges and evaluated with aqueous test samples, natural water and human urine; a quantitative method for methylxanthines in water, using SPE cartridges packed with the MIS coupled with HPLC-UV was developed. The MIS was highly specific for methylxanthines, with an imprinting factor of (20.5+/-1.9). The analytical method resulted in detection limits of 85 microgL(-1) for theobromine, 44 microgL(-1) for theophylline and 53 microgL(-1) for caffeine.
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: D002851:Chromatography, High Pressure Liquid / Q000379:methods; D044367:Phase Transition; D012680:Sensitivity and Specificity; D012833:Siloxanes / Q000737:chemistry*; D013055:Spectrophotometry, Infrared; D014466:Ultraviolet Rays; D014970:Xanthines / Q000302:isolation & purification* / Q000652:urine
chemical_list: D012833:Siloxanes; D014970:Xanthines; C510784:ormosil; C008514:methylxanthine