Lecture
Quantum Cascade Laser Vibrational Circular Dichroism - Towards Online Chiral Monitoring
- at -
- ICM Saal 3
- Type: Lecture
Lecture description
G. Ramer, Vienna, AT; V. Rohringer, Vienna, AT; D. Hermann, Vienna, AT; B. Lendl, Vienna, AT;
Vibrational circular dichroism (VCD) uses the differential absorption of left and right handed circular polarized mid-infrared light for chiral analysis of samples. VCD can provide information on enantiomeric excess, can be used to assign chiral centers through specific functional groups through the well-known relationships between wavenumber and chemical bonds in the mid-IR and and can be used to establish total configuration of a molecule. However, VCD is also a notoriously slow and insensitive technique, with a single spectrum taking an hour or longer and typical analyte concentrations in solution being close to saturation. This has so far precluded the practical use of VCD or process analytical spectroscopy. To solve both problems we’ve recently developed a novel external cavity quantum cascade laser (EC-QCL) based VCD technique.
This technique leverages broadly intense, tunable mid-infrared EC-QCLs for significantly faster VCD data acquisition. The QCL-VCD technique enables to acquire VCD spectra within few minutes at the same level of sensitivity as conventional techniques that take hours [1]. We have demonstrated the use of this high throughput VCD technique for quantification of enantiomeric excess, leveraging chemometric techniques for rapidly extracting information from VCD and absorption spectra at the same time [2] and for the analysis of proteins [3].
Our ongoing research aims to further improve the throughput and stability of QCL-VCD towards a process analytical technique with capability for real-time on-line chiral sensing.
Literature:
[1] D. R. Hermann, G. Ramer, M. Kitzler-Zeiler, and B. Lendl, “Quantum Cascade Laser-Based Vibrational Circular Dichroism Augmented by a Balanced Detection Scheme,” Anal. Chem., vol. 94, no. 29, pp. 10384–10390, 2022, doi: 10.1021/acs.analchem.2c01269.
[2] D.-R. Hermann, G. Ramer, L. Riedlsperger, and B. Lendl, “Chiral Monitoring Across Both Enantiomeric Excess and Concentration Space: Leveraging Quantum Cascade Lasers for Sensitive Vibrational Circular Dichroism Spectroscopy,” Appl. Spectrosc., p. 00037028231206186, Oct. 2023, doi: 10.1177/00037028231206186.
[3] D.-R. Hermann, G. Ramer, and B. Lendl, “External cavity quantum cascade laser vibrational circular dichroism spectroscopy for fast and sensitive analysis of proteins at low concentrations,” Anal. Chem., Nov. 2024, doi: 10.1021/acs.analchem.4c03498.
Vibrational circular dichroism (VCD) uses the differential absorption of left and right handed circular polarized mid-infrared light for chiral analysis of samples. VCD can provide information on enantiomeric excess, can be used to assign chiral centers through specific functional groups through the well-known relationships between wavenumber and chemical bonds in the mid-IR and and can be used to establish total configuration of a molecule. However, VCD is also a notoriously slow and insensitive technique, with a single spectrum taking an hour or longer and typical analyte concentrations in solution being close to saturation. This has so far precluded the practical use of VCD or process analytical spectroscopy. To solve both problems we’ve recently developed a novel external cavity quantum cascade laser (EC-QCL) based VCD technique.
This technique leverages broadly intense, tunable mid-infrared EC-QCLs for significantly faster VCD data acquisition. The QCL-VCD technique enables to acquire VCD spectra within few minutes at the same level of sensitivity as conventional techniques that take hours [1]. We have demonstrated the use of this high throughput VCD technique for quantification of enantiomeric excess, leveraging chemometric techniques for rapidly extracting information from VCD and absorption spectra at the same time [2] and for the analysis of proteins [3].
Our ongoing research aims to further improve the throughput and stability of QCL-VCD towards a process analytical technique with capability for real-time on-line chiral sensing.
Literature:
[1] D. R. Hermann, G. Ramer, M. Kitzler-Zeiler, and B. Lendl, “Quantum Cascade Laser-Based Vibrational Circular Dichroism Augmented by a Balanced Detection Scheme,” Anal. Chem., vol. 94, no. 29, pp. 10384–10390, 2022, doi: 10.1021/acs.analchem.2c01269.
[2] D.-R. Hermann, G. Ramer, L. Riedlsperger, and B. Lendl, “Chiral Monitoring Across Both Enantiomeric Excess and Concentration Space: Leveraging Quantum Cascade Lasers for Sensitive Vibrational Circular Dichroism Spectroscopy,” Appl. Spectrosc., p. 00037028231206186, Oct. 2023, doi: 10.1177/00037028231206186.
[3] D.-R. Hermann, G. Ramer, and B. Lendl, “External cavity quantum cascade laser vibrational circular dichroism spectroscopy for fast and sensitive analysis of proteins at low concentrations,” Anal. Chem., Nov. 2024, doi: 10.1021/acs.analchem.4c03498.
