Ultraviolet sealing and poly(dimethylacrylamide) modification for poly(dimethylsiloxane)/glass microchips.
Simple sealing methods for poly(dimethylsiloxane) (PDMS)/glass-based capillary electrophoresis (CE) microchips by UV irradiation are described. Further, we examined the possibility to modify the inner surface of separation channels, using polymethylacrylamide (PDMA) as a dynamic coating reagent. The surface properties of native PDMS, UV-irradiated PDMS, and PDMA-coated PDMS were systematically studied by atomic force microscopy (AFM), infrared absorption by attenuated total reflection infrared (ATR-IR) spectroscopy, and contact angle measurement. We found that PDMA forms a stable coating on PDMS and glass surfaces, eliminating the nonhomogeneous electroosmotic flow (EOF) in channels on PDMS/glass microchips, and improving the hydrophilicity of PDMS surfaces. Mixtures of flavin mononucleotide (FMN), flavin adenine dinucleotide (FAD), and fluorescein were separated in 35 s using PDMA-coated PDMS/glass microchips. A high efficiency of theoretical plates with at least 1365 (105 000 N/m) and a good reproducibility with relative standard deviations (RSD) below 4% in five successive separations were achieved.
Chen
Lin
L
College of Chemistry and Chemical Engineering, Shanghai Jiaotong University, 800 Dongchuan Road, Shanghai 200240, P.R. China.
Ren
Jicun
J
Bi
Rui
R
Chen
Di
D
D000178:Acrylamides / Q000737:chemistry*; D004129:Dimethylpolysiloxanes / Q000737:chemistry*; D019075:Electrophoresis, Capillary / Q000295:instrumentation / Q000379:methods*; D005486:Flavin Mononucleotide / Q000302:isolation & purification; D005182:Flavin-Adenine Dinucleotide / Q000302:isolation & purification; D019793:Fluorescein / Q000302:isolation & purification; D005898:Glass / Q000737:chemistry*; D018625:Microscopy, Atomic Force; D008904:Miniaturization; D015394:Molecular Structure; D009757:Nylons / Q000737:chemistry; D010777:Photochemistry; D014466:Ultraviolet Rays
D000178:Acrylamides; D004129:Dimethylpolysiloxanes; D009757:Nylons; C429790:poly(N,N-dimethylacrylamide); C085707:poly(dimethylsiloxane)-polyamide copolymer; D005182:Flavin-Adenine Dinucleotide; D005486:Flavin Mononucleotide; D019793:Fluorescein