Title: | Beyond FT-IR spectroscopy: EC-QCL based mid-IR transmission spectroscopy of proteins in the amide I and amide II region | Language: | English | Authors: | Schwaighofer, Andreas Montemurro, Milagros Freitag, Stephan ![]() Kristament, Christian Culzoni, Maria Julia Lendl, Bernhard ![]() |
Issue Date: | 2018 | Journal: | Analytical Chemistry | Abstract: | In this work, we present a setup for mid-IR measurements of the protein amide I and amide II bands in aqueous solution. Employing a latest generation external cavityquantum cascade laser (EC-QCL) at room temperature in pulsed operation mode allowed implementing a high optical path length of 31 μm that ensures robust sample handling. By application of a data processing routine, which removes occasionally deviating EC-QCL scans, the noise level could be lowered by a factor of 4. The thereby accomplished signal-to-noise ratio is better by a factor of approximately 2 compared to research-grade Fourier transform infrared (FT-IR) spectrometers at equal acquisition times. Employing this setup, characteristic spectral features of three representative proteins with different secondary structures could be measured at concentrations as low as 1 mg mL−1. Mathematical evaluation of the spectral overlap confirms excellent agreement of the quantum cascade laser infrared spectroscropy (QCL-IR) transmission measurements with protein spectra acquired by FT-IR spectroscopy. The presented setup combines performance surpassing FT-IR spectroscopy with large applicable optical paths and coverage of the relevant spectral range for protein analysis. This holds high potential for future ECQCL-based protein studies, including the investigation of dynamic secondary structure changes and chemometrics-based protein quantification in complex matrices. |
DOI: | 10.1021/acs.analchem.8b01632 | Library ID: | AC15518671 | URN: | urn:nbn:at:at-ubtuw:3-7499 | ISSN: | 1520-6882 | Organisation: | E164 - Institut für Chemische Technologien und Analytik | Publication Type: | Article Artikel |
Appears in Collections: | Article |
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Beyond FT-IR spectroscopy EC-QCL based mid-IR transmission spectroscopy of proteins in the amide I and amide II region.pdf | 1.03 MB | Adobe PDF | ![]() View/Open |
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