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This paper presents an entirely polymeric microfluidic system, made of cyclo olefin polymer (COP), with integrated gold microband electrodes for electrochemical applications in organic media. In the present work, we take advantage of the COP's high chemical stability to polar organic solvents in two different ways: (i) to fabricate gold microelectrodes using COP as a substrate by standard lithographic and lift-off techniques; and (ii) to perform electrochemical experiments in organic media. In particular, fourteen parallel gold microelectrodes with a width of 14 μm and separated from their closest neighbour by 16 μm were fabricated by lithographic and lift-off techniques on a 188 μm thick COP sheet. A closed channel configuration was obtained by pressure-assisted thermal bonding between the COP sheet containing the microelectrodes and a microstructured COP sheet, where a 3 cm long, 50 μm wide and 24 μm deep channel was fabricated viahot embossing. Cyclic voltammetric measurements were carried out in aqueous and organic media, using a solution consisting of 5 mM ferrocyanide/ferricyanide in 0.5 M KNO3and 5 mM ferrocene in 0.1 M TBAP/acetonitrile, respectively. Experimental currents obtained for different flow rates ranging from 1 to 10 μL min−1were compared to the theoretical steady state currents calculated by the Levich equation for a band electrode (R. G. Compton, A. C. Fisher, R. G. Wellington, P. J. Dobson and P. A. Leigh, J. Phys. Chem., 1993, 97, 10410–10415). In both cases, the difference between the experimental and the predicted data is less than 5%, thus validating the behaviour of the fabricated device. This result opens the possibility to use a microfluidic system made entirely from COP with integrated microband electrodes in organic electroanalysis and in electrosynthesis. [ABSTRACT FROM AUTHOR]

The current paper describes the development and characterization of a pillar array chip that is constructed out of a sandwich of cyclo olefin polymer (COP) sheets. The silicon master of a 5 cm long pillar array was embossed into the COP, yielding 4.3 µm deep pillars of 15.3 µm diameter with an external porosity of 43 % and a well designed sidewall region to avoid side wall induced band broadening. A closed channel configuration was obtained by pressure assisted thermal bonding to a non-processed COP lid. Injection of coumarin dye plugs and detection with a fluorescence microscope showed very close agreement of this channel configuration to theoretical expectations in terms of band broadening. This agreement is due to the low taper, the optimized sidewall region and the excellent bonding quality between the two polymer sheets, even at the pillar area. Under non-retained conditions (pure methanol as mobile phase), plate heights as low as 4 µm were obtained. Under retained conditions, using the native hydrophobic properties of the COP channel (in 70/30 v/v water/methanol mixture as mobile phase), a minimum plate height of 6 µm was obtained. A 4 component separation was successfully achieved, demonstrating that COP is a cheap and efficient alternative for silicon and silica based liquid chromatography formats. [ABSTRACT FROM AUTHOR]