A DFT-based Raman spectral atlas and vibrational assignment of aqueous glucose structures and derivatives

Area of Science:

• Analytical Chemistry
• Computational Chemistry
• Biomedical Spectroscopy

Background:

• Diabetes mellitus affects millions globally, necessitating improved noninvasive glucose monitoring.
• Raman spectroscopy offers potential for noninvasive glucose detection but is hindered by simplified glucose models and unresolved spectral band assignments.

Purpose of the Study:

• To elucidate the vibrational origins of glucose bands using computational and experimental methods.
• To create a comprehensive, validated Raman spectral atlas for aqueous glucose structures.
• To identify specific spectral markers for various glucose forms and derivatives.

Main Methods:

• Density functional theory (DFT) simulations were employed to model glucose structures.
• Experimental Raman spectroscopy was used to obtain spectral data for various glucose tautomers and derivatives.
• Theoretical and experimental results were combined to validate spectral assignments.

Main Results:

• A comprehensive Raman spectral atlas with validated assignments for aqueous glucose structures was generated.
• Unprecedented agreement between DFT simulations and experimental Raman spectra was achieved.
• Specific spectral markers were identified to differentiate glucose pyranose and furanose rings, anomeric configurations, hydration states, and 1,5-Anhydroglucitol.

Conclusions:

• This study resolves long-standing controversies in glucose vibrational spectroscopy.
• The validated spectral atlas provides essential reference standards for Raman-based glucose monitoring.
• Findings advance noninvasive monitoring of glycemic control and early glycation risk in diabetic patients.