[Journal of Chromatography A] Prototyping of thermoplastic microfluidic chips and their application
The present paper discusses practical aspects of prototyping of microfluidic chips using cyclic olefin copolymer and the application in high-performance liquid chromatography. The developed chips feature a 60 mm long straight separation channel with circular cross section (500 μm i.d.) that was created using a micromilling robot. To irreversibly seal the top and bottom chip substrates, a solvent-vapor-assisted bonding approach was optimized, without compromising the ideal circular channel geometry. Four different approaches to establish the micro-to-macro interface were pursued. The average burst pressure of the microfluidic chips in combination with an encasing holder was established at 38 MPa and the maximum burst pressure was 47 MPa, which is believed to be the highest ever report for these polymer-based microfluidic chips. Porous polymer monolithic frits were synthesized in-situ via UV-initiated polymerization and their locations were spatially controlled by the application of a photomask. Next, high-pressure slurry packing was performed to introduce 3 μm silica reversed-phase particles as the stationary phase in the separation channel. Finally, the application of the chip technology is demonstrated for the separation of alkyl phenones in gradient mode yielding baseline peak widths of 6 s by applying a steep gradient of 1.8 min at a flow rate of 10 μL/min.
Sam Wouters1, Jelle De Vos1, José Luís Dores- Sousa, Bert Wouters, Gert Desmet, Sebastiaan Eeltink, Vrije Universiteit Brussel (VUB), Department of Chemical Engineering, Brussels, Belgium Received 15 March 2017, Revised 4 May 2017, Accepted 29 May 2017, Available online 1 June 2017 Show less https://doi.org/10.1016/j.chroma.2017.05.063