Quantification of hydrogen bonding strength of water in saccharide aqueous solutions by confocal Raman microscopy

Abstract

Raman spectroscopy has been employed for studying water structures in biomolecular aqueous solutions for decades but challenges remain to quantify the hydrogen bonding strengths in complex aqueous solution systems. In this study, four kinds of saccharide aqueous solutions were employed to investigate the quantitative relationship between the hydrogen bonding strength of water using confocal Raman microscopy and the Raman spectra of these solutions in the range of 3000–3800 cm−1. Results showed that the enhancement effect of saccharide molecules on the hydrogen bonding strength of water increased with the concentration, and the degree of changes in the strength was related to the hydration capability and partial molal volume of saccharide molecules. An equation based on the average number of hydrogen bonds of water molecule was proposed to quantify the bonding strength in saccharide aqueous solutions with satisfactory accuracy as verified by T2 relaxation time using nuclear magnetic resonance spectrometer.