title: Polymer monolith-integrated multilayer poly(dimethylsiloxane) microchip for online microextraction and capillary electrophoresis.
abstract: We reported the in situ synthesis and use of porous polymer monolith (PPM) columns in an integrated multilayer PDMS/glass microchip for microvalve-assisted on-line microextraction and microchip electrophoresis for the first time. Under the control of PDMS microvalves, the grafting of the microchannel surface and in situ photopolymerization of poly(methacrylic acid-co-ethylene glycol dimethacrylate) monolith in a defined zone were successfully achieved. Different factors including the surface grafting, polymerization time, PDMS elastic properties (ratio of oligomer/curing reagent) and UV intensity that affect the monolith synthesis in the PDMS microchannel were investigated and optimized. Dopamine, a model analyte, has been online microextracted, eluted, electrophoresized and electrochemically detected in the microchip, with a mean concentration enrichment factor of 80 (n=3). The results demonstrated that the PPM could be synthesized successfully in the PDMS microchip with a homogeneous structure and excellent mechanical properties. Furthermore, owing to the intrinsic character using PDMS in large-scale integrated microsystems, the implantation of PPM pretreatment units in PDMS microchips would make it possible to deal with complicated analytical processes in a high-throughput way.
authors.affiliation: Key Laboratory of Analytical Chemistry for Biology and Medicine (Ministry of Education), College of Chemistry and Molecular Sciences, Wuhan University, Wuhan, P R China.
authors.forename: Qin-Shu
authors.initials: QS
authors.lastname: Kang
authors.forename: Yun
authors.initials: Y
authors.lastname: Li
authors.forename: Jun-Qing
authors.initials: JQ
authors.lastname: Xu
authors.forename: Li-Jin
authors.initials: LJ
authors.lastname: Su
authors.forename: Yu-Tao
authors.initials: YT
authors.lastname: Li
authors.forename: Wei-Hua
authors.initials: WH
authors.lastname: Huang
mesh_terms: D004129:Dimethylpolysiloxanes / Q000737:chemistry*; D004298:Dopamine / Q000032:analysis / Q000737:chemistry; D046209:Electrophoresis, Microchip / Q000379:methods*; D005026:Ethylene Glycols / Q000737:chemistry; D005898:Glass; D016014:Linear Models; D008689:Methacrylates / Q000737:chemistry; D008855:Microscopy, Electron, Scanning; D016062:Porosity; D052617:Solid Phase Microextraction / Q000379:methods*
chemical_list: D004129:Dimethylpolysiloxanes; D005026:Ethylene Glycols; D008689:Methacrylates; C502776:poly(methacrylic acid-ethylene glycol dimethacrylate); C013830:baysilon; D004298:Dopamine