Micro flow reactor chips with integrated luminescent chemosensors for spatially resolved on-line chemical reaction monitoring

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 μm width and of 10 to 35 μm height. Sensor layers consisting of polystyrene and an oxygen-sensitive platinum porphyrin probe with film thicknesses of about 0.5 to 4 μm 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 μg 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 μM. 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.

Development of microscopic time‐domain dual lifetime referencing luminescence detection for pH monitoring in microfluidic free‐flow isoelectric focusing

“…The developed optical setup and sensor integration technique could also be useful in other microfluidic systems for the precise and fast online observation of pH, for example in chemical reaction monitoring [55], separation or in cell culture systems [56]. Furthermore, with appropriate calibration, the reference fluorophore could also be used for simultaneous temperature detection which would offer further parameter observation.…”

Micro Total Analysis Systems: Fundamental Advances and Biological Applications

“…One example involved the use of a platinum porphyrin polymer luminescent probe to monitor dissolved oxygen in microfluidic channels. 122 The probe was used to follow the oxidation of small inorganic compounds. While fluorescence provides excellent sensitivity and selectivity, most molecules are either not fluorescent or difficult to derivatize, especially on column.…”

An integrated microfluidic chip enabling control and spatially resolved monitoring of temperature in micro flow reactors

“…The presented work builds upon a previously introduced fabrication method for coating the inner wall of microchannels of glass-PDMS chips with a thin polymer layer for oxygen sensing [77]. This enables the introduction of a chemical probe together with a shielding polymer inside a micro flow channel.…”