[Zurück]

B. Lendl, C. Koch, M. Brandstetter:
"New Approaches For Chemical Sensing Based On Vibrational Spectroscopy";
Hauptvortrag: EUCMOS Xxxi, Cluj-Napoca (eingeladen); 26.08.2012 - 31.08.2012.

Advances in technology for infrared spectrometry are of key importance in the development of innovative analysis systems for use in applied environmental and process monitoring as well as in basic (bio)chemical research. These advances can include novel optical components such as light sources, detectors and fiber optics, but also supporting technologies for enabling new measurement concepts. This presentation reports on recent developments which make use of such technological advances.
This presentation will introduce Quantum Cascade Lasers (QCLs) as a new light source for use in chemical sensors. Step-scan FTIR spectroscopy has been used to characterize pulsed operation of these lasers with a time resolution of 2 ns and a spectral resolution of 0.1 cm-1. Based on these data optimum conditions were found which enabled the implementation of QCLs in a new generation of chemical analyzers. This presentation will report on a recent commercial realization of a QCL based instrument for the determination of oil in water [1]. In the area of biochemical analysis a portable QCL based sensor system for the determination of various parameters in human serum will be shown as well.
A new technology for measuring microorganism inside an industrial bioreactor based on a combination of ultrasonic particle manipulation and fiber optic mid-IR spectroscopy will be presented in continuation. A standing MHz ultrasound field established between the planar attenuated total reflection (ATR) surface of a fiber optic probe and a piezo-ceramic element placed at a distance of a few millimeters can be used to manipulate particles in a suspension. Particles such as beads or microorganisms are captured in the nodes of the standing pressure waves. By controlling the frequency of the standing waves the particles can either be kept away from the ATR surface or pressed against it. In such a way a fiber optic in-line sensor system can be envisioned which is capable to discriminate between particles (micro-organism) and solutes (substrates and products) in a given suspension (fermentation). Data obtained from yeast fermentations will be highlight the achieved state of the art.