Optical non-contact localization of liquid-gas interfaces on disk during rotation for measuring flow rates and viscosities.

Authors:
Jochen Hoffmann
Jochen Hoffmann
University of Freiburg
Germany
Frederik Bundgaard
Frederik Bundgaard
Rigshospitalet
København | Denmark
Daniel Mark
Daniel Mark
Duke Clinical Research Institute
United States
Roland Zengerle
Roland Zengerle
University of Freiburg
Germany
Dr. Jens Ducree, Dr. rer. nat. habil. Dipl. Phys.
Dr. Jens Ducree, Dr. rer. nat. habil. Dipl. Phys.
Fraunhofer Project Centre at Dublin City University
Professor (Full)
microfluidics, Lab-on-a-Chip, hydrodynanmics, business development, project management, organisational leadership
Glasnevin, Dublin 9 | Ireland

Lab Chip 2012 Dec;12(24):5231-6

Laboratory for MEMS Applications, Department of Microsystems Engineering-IMTEK, University of Freiburg, Georges-Koehler-Allee 103, Freiburg, 79110, Germany.

We present a novel technique for the spatio-temporally resolved localization of liquid-gas interfaces on centrifugal microfluidic platforms based on total internal reflection (TIR) at the channel wall. The simple setup consists of a line laser and a linear image sensor array mounted in a stationary instrument. Apart from identifying the presence of usually unwanted gas bubbles, the here described online meniscus detection allows to measure liquid volumes with a high precision of 1.9%. Additionally, flow rates and viscosities (range: 1-12 mPa s, precision of 4.3%) can be sensed even during rotation at frequencies up to 30 Hz.

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http://dx.doi.org/10.1039/c2lc40842bDOI Listing
December 2012
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