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S. Radel, J. Schnöller, A. Dominguez-Vidal, B. Lendl, M. Gröschl, E. Benes:
"Ultrasonic particle manipulation approaches in on-line ATR FTIR";
Vortrag: 3rd Congress of the Alps Adria Acoustics Association, Hotel Weitzer, Graz; 27.09.2007; in: "3rd Congress of the Alps Adria Acoustics Association, Hrsg: Joanneum Research", (2007), 4 S.

In this work an ultrasonic standing wave field of 2 MHz was used to manipulate particles in an on-line flow
cell cells for fourier transformed mid-infrared spectroscopy (FTIR) purposes.
This optical measurement technique is increasingly popular in process analytical chemistry because of its ability to
directly provide molecular specific information about a given sample. Especially in the regime of bioprocess control
robust and reliable sensors with fast response times are needed. A target is to discriminate between biological cells and
the supernatant, i.e. the suspending liquid during the measurement.
Employing the principles of ultrasonic particle manipulation we have developed a novel flow cell for a horizontal
attenuated total reflection (ATR) unit connected to a portable mid-infrared spectrometer. Results show, that a
significant decrease of the undesired formation of bio-films on the attenuated total reflection surface (which is
unavoidable when using suspensions like fermentation broth) was achieved. In addition the time resolution was more
than doubled.

ultrasonic particle manipulation, standing wave, IR spectroscopy

http://publik.tuwien.ac.at/files/pub-tch_8315.pdf