title: Acylated-naproxen as the surface-active template in the preparation of micro- and nanospherical imprinted xerogels by emulsion techniques.
abstract: A strategy based on water-in-oil emulsion for the dispersion of a sol-gel mixture into small droplets was employed with the view of the production of naproxen-imprinted micro- and nanospheres. The procedure, aiming at a surface imprinting process, comprised the synthesis of a naproxen-derived surfactant. The imprinting process occurred at the interface of the emulsions or microemulsions, by the migration of the NAP-surfactant head into the sol-gel drops to leave surficial imprints due mainly to ion-pair interaction with a cationic group contained within the growing sol-gel network. The surface-imprinted microspheric particles exhibited a log-normal size distribution with geometric mean diameter of 3.1μm. A mesoporous texture was found from measurements of the specific surface area (206m(2)/g) and pore diameter (Dp 2nm). Evaluation of the microspheres as packed HPLC stationary phases resulted in the determination of the selectivity factor against ibuprofen (α=2.1), demonstrating the successful imprinting. Chromatographic efficiency, evaluated by the number of theoretical plates (222platescm(-3)), emerged as an outstanding feature among the set of all relatable formats produced before, an advantage intrinsic to the location of the imprinted sites on the surface. The material presented a capacity of 3.2μmolg(-1). Additionally, exploratory work conducted on their nanoscale counterparts resulted in the production of nanospheres in the size order of 10nm providing good indications of a successful imprinting process.
authors.affiliation: Centro de Investigação em Química-CIQUP, Faculty of Sciences, University of Porto, Rua do Campo Alegre, 4169-007 Porto, Portugal.
authors.forename: Mariana
authors.initials: M
authors.lastname: Ornelas
authors.affiliation: Centro de Investigação em Química-CIQUP, Faculty of Sciences, University of Porto, Rua do Campo Alegre, 4169-007 Porto, Portugal. Electronic address: mazenha@fc.up.pt.
authors.forename: Manuel
authors.initials: M
authors.lastname: Azenha
authors.affiliation: Centro de Investigação em Química-CIQUP, Faculty of Sciences, University of Porto, Rua do Campo Alegre, 4169-007 Porto, Portugal.
authors.forename: Maria João
authors.initials: MJ
authors.lastname: Araújo
authors.affiliation: Centro de Investigação em Química-CIQUP, Faculty of Sciences, University of Porto, Rua do Campo Alegre, 4169-007 Porto, Portugal.
authors.forename: Eduardo F
authors.initials: EF
authors.lastname: Marques
authors.affiliation: CICS-UBI-Health Sciences Research Centre, University of Beira Interior, 6200-506 Covilhã, Portugal and Department of Chemistry, University of Beira Interior, 6200-001 Covilhã, Portugal.
authors.forename: A C
authors.initials: AC
authors.lastname: Dias-Cabral
authors.affiliation: Centro de Investigação em Química-CIQUP, Faculty of Sciences, University of Porto, Rua do Campo Alegre, 4169-007 Porto, Portugal.
authors.forename: Carlos
authors.initials: C
authors.lastname: Pereira
authors.affiliation: Centro de Investigação em Química-CIQUP, Faculty of Sciences, University of Porto, Rua do Campo Alegre, 4169-007 Porto, Portugal.
authors.forename: A Fernando
authors.initials: AF
authors.lastname: Silva
mesh_terms: D000215:Acylation; D002623:Chemistry Techniques, Analytical / Q000379:methods*; D004655:Emulsions / Q000737:chemistry*; D005782:Gels / Q000138:chemical synthesis* / Q000737:chemistry; D007052:Ibuprofen / Q000737:chemistry; D008863:Microspheres; D054802:Molecular Imprinting / Q000379:methods; D054118:Nanospheres; D009288:Naproxen / Q000737:chemistry*; D013501:Surface-Active Agents / Q000737:chemistry
chemical_list: D004655:Emulsions; D005782:Gels; D013501:Surface-Active Agents; D009288:Naproxen; D007052:Ibuprofen
keywords: Acylated-naproxen; Silica microspheres; Silica nanospheres; Sol–gel; Surface imprinting; W/O emulsion