Optical non-contact localization of liquid-gas interfaces on disk during rotation for measuring flow rates and viscosities
31.10.2012
Hoffmann J, Riegger L, Bundgaard F, Mark D, Zengerle R, Ducrée J
Lab Chip. 2012; 12(24):5231-6
We present a 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.
