CD Laboratory for Advanced Mid-lnfrared Laser Spectroscopy in (Bio-)process Analytics

This CD Laboratory researches the interactions between laser radiation in the mid-infrared range and chemical samples: Based on this basic research, the next generation of highly sensitive chemical sensors, such as those required for process and environmental analysis, will be made possible.

In various manufacturing processes, especially in safety-critical areas such as pharmaceutical production, fast and reliable test methods are important for quality control. Spectroscopy utilising the mid-infrared range (MIR), or MIR spectroscopy for short, has proven to be a promising process analytical technology: it can be used to obtain a wide range of molecule-specific information within seconds to a few minutes and gain additional insights into protein folding, for example, without damaging or altering the tested samples.

However, the CD Laboratory team is going one step further and investigating how such methods can be refined even further if widely determinable infrared semiconductor lasers are used, i.e. IR semi-conductor lasers with broadly tunable emission wavelength: so-called "external cavity - quantum cascade lasers" or EC-QCLs, which belong to this group, offer the potential for the development of chemical analysers that outperform even high-end conventional infrared spectrometers - and can even detect individual molecules.

The CD Laboratory has therefore set itself the goal of further developing EC-QCL-IR spectroscopy beyond the state of the art in order to enable highly sensitive and reproducible process analysis, allowing complex samples to be tested multiple times during production processes (in-line or on-line). However, this principle can not only be applied to industrial processes such as those in the pharmaceutical industry, but can also be used in environmental analysis, for example for the detection of organic trace impurities in water.

The team´s basic research is based on two parallel lines of investigation: On the one hand, novel spectroscopic measurement techniques are to be developed that surpass conventional absorption techniques by utilising special EC-QCL properties in terms of information richness and sensitivity. On the other hand, the interactions of MIR radiation and complex samples need to be studied in detail for interactions in order to incorporate the understanding gained into the development of sophisticated techniques for data analysis: The desired chemical information can only be correctly derived from the MIR spectra if the properties of the sample and instrument as well as the ambient conditions influence the spectral signatures of molecules and sample mixtures.

The work of the CD Laboratory thus makes an important contribution to the quality testing of important products and resources, from chemical (pharmaceutical) products to (drinking) water.