Vibrational coupling to hydration shell - Mechanism to performance enhancement of qualitative analysis in NIR spectroscopy of carbohydrates in aqueous environment

Anel Beganović; Krzysztof B Beć; Justyna Grabska; Manuel T Stanzl; Martin E Brunner; Christian W Huck

doi:10.1016/j.saa.2020.118359

Vibrational coupling to hydration shell - Mechanism to performance enhancement of qualitative analysis in NIR spectroscopy of carbohydrates in aqueous environment

Spectrochim Acta A Mol Biomol Spectrosc. 2020 Aug 15:237:118359. doi: 10.1016/j.saa.2020.118359. Epub 2020 Apr 16.

Authors

Anel Beganović¹, Krzysztof B Beć¹, Justyna Grabska¹, Manuel T Stanzl¹, Martin E Brunner¹, Christian W Huck²

Affiliations

¹ Institute of Analytical Chemistry and Radiochemistry, CCB-Center for Chemistry and Biomedicine, Innrain 80/82, 6020 Innsbruck, Austria.
² Institute of Analytical Chemistry and Radiochemistry, CCB-Center for Chemistry and Biomedicine, Innrain 80/82, 6020 Innsbruck, Austria. Electronic address: christian.w.huck@uibk.ac.at.

PMID: 32413729
DOI: 10.1016/j.saa.2020.118359

Abstract

Vibrational coupling between carbohydrates and the hydration shell is unveiled as the underlying mechanism that improves wavenumber-selectively the carbohydrate discrimination performance by near-infrared (NIR) spectroscopy. The investigation is based on measurement of six carbohydrates (fructose, glucose, mannose, ribose, xylose and sorbitol) in aqueous solution in different concentration levels (5 mg/L, ~0.03 mmol/dm^-3 and 20 mg/L, ~0.1 mmol/dm^-3). The results of multivariate classification are interpreted by quantum mechanical NIR spectra simulations. The simulation unveils that the phenomenon is vibration-selective and thus wavenumber-selective, and leads to an enhancement of the qualitative information contained in the specific spectral regions. The location of these regions and the related performance correspond fully to the appearance and magnitude of the unveiled cooperative vibration effect.

Keywords: Band assignment; Carbohydrate; Hydration shell; Linear discriminant analysis; Near-infrared spectroscopy; Principle component analysis; Vibration coupling.