Abstract
Real-time chemical reaction monitoring in microfluidic environments is demonstrated using luminescent chemical sensors integrated in PDMS/glass-based microscale reactors. A fabrication procedure is presented that allows for straightforward integration of thin polymer layers with optical sensing functionality in microchannels of glass-PDMS chips of only 150 mm width and of 10 to 35 mm height. ...
Abstract
Real-time chemical reaction monitoring in microfluidic environments is demonstrated using luminescent chemical sensors integrated in PDMS/glass-based microscale reactors. A fabrication procedure is presented that allows for straightforward integration of thin polymer layers with optical sensing functionality in microchannels of glass-PDMS chips of only 150 mm width and of 10 to 35 mm height. Sensor layers consisting of polystyrene and an oxygen-sensitive platinum porphyrin probe with film thicknesses of about 0.5 to 4 mm were generated by combining spin coating and abrasion techniques. Optimal coating procedures were developed and evaluated. The chip-integrated sensor layers were calibrated and investigated with respect to stability, reproducibility and response times. These microchips allowed observation of dissolved oxygen concentration in the range of 0 to over 40 mg L-1 with a detection limit of 368 mu g L-1. The sensor layers were then used for observation of a model reaction, the oxidation of sulphite to sulphate in a microfluidic chemical reactor and could observe sulphite concentrations of less than 200 mu M. Real-time on-line monitoring of this chemical reaction was realized at a fluorescence microscope setup with 405 nm LED excitation and CCD camera detection.
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