title: An organically modified silicate molecularly imprinted solid-phase microextraction device for the determination of polybrominated diphenyl ethers.
abstract: An organically modified silicate (ORMOSIL) SPME stationary phase molecularly imprinted with BDE-209 has been successfully fabricated by conventional sol-gel technique from phenyltrimethoxysilane and tetraethoxysilane. The thickness of the ORMOSIL-SPME stationary phase, on fused-silica optical fibres, was measured to be ca. 9.5 microm with a volume of ca. 0.12 microL. Rebinding assays and Scatchard analysis revealed that the imprinted ORMOSIL-SPME stationary phase possessed a binding affinity, K(B), of 7.3+/-1.7 x 10(10)M(-1) for BDE-209, with a receptor site density, B(max), of 1.2 x 10(-3)pmol per SPME device. Besides its molecular template, the ORMOSIL-SPME stationary phase also showed good affinity (logK(B)>/=9.5) for smaller BDE congeners commonly found in the natural environment. The density of receptor sites within the imprinted matrix for those smaller BDE congeners was even higher than that for BDE-209. This may be attributable to the binding site heterogeneity of the imprinting process that creates deformed binding sites that are suitable for the accommodation of the smaller BDE congeners. Compared to the commercially available polyacrylate and polydimethylsiloxane SPME stationary phases, the imprinted ORMOSIL-SPME devices showed much higher pre-concentration ability towards polybrominated diphenyl ethers (PBDEs), even in direct immersion sampling at room temperature. Coupled with GC-NCI-MS and GC-muECD, the imprinted ORMOSIL-SPME device was able to achieve detection sensitivity of 0.2-3.6 pgmL(-1) and 1-8.8 pgmL(-1), respectively, for commonly occurring BDE congeners, including medium to high molecular weight PBDEs. The imprinted ORMOSIL-SPME device has been successfully applied to monitor PBDE contents in municipal wastewaters.
authors.affiliation: Centre for Coastal Pollution & Conservation, Department of Biology & Chemistry, City University of Hong Kong, Tat Chee Ave., Kowloon, Hong Kong, China.
authors.forename: Maggie Ka-Yi
authors.initials: MK
authors.lastname: Li
authors.forename: Ngai-Yu
authors.initials: NY
authors.lastname: Lei
authors.forename: Chengbin
authors.initials: C
authors.lastname: Gong
authors.forename: Yijun
authors.initials: Y
authors.lastname: Yu
authors.forename: Ka-Ho
authors.initials: KH
authors.lastname: Lam
authors.forename: Michael Hon-Wah
authors.initials: MH
authors.lastname: Lam
authors.forename: Hongxia
authors.initials: H
authors.lastname: Yu
authors.forename: Paul Kwan-Sing
authors.initials: PK
authors.lastname: Lam
mesh_terms: D000327:Adsorption; D001665:Binding Sites; D004785:Environmental Pollutants / Q000032:analysis; D055768:Halogenated Diphenyl Ethers / Q000032:analysis* / Q000737:chemistry; D055100:Optical Fibers; D017646:Organosilicon Compounds / Q000737:chemistry; D012680:Sensitivity and Specificity; D012821:Silanes / Q000737:chemistry; D017640:Silicates / Q000737:chemistry*; D052617:Solid Phase Microextraction / Q000295:instrumentation / Q000379:methods*; D014867:Water / Q000737:chemistry
chemical_list: D004785:Environmental Pollutants; D055768:Halogenated Diphenyl Ethers; D017646:Organosilicon Compounds; D012821:Silanes; D017640:Silicates; D014867:Water; C410706:phenyltrimethoxysilane; C040733:tetraethoxysilane; C010902:decabromobiphenyl ether