Hydrolyzation-Free Characterization of Acetalated Dextranvia 2D Correlated Raman Spectroscopy

This study demonstrates a hydrolysis-free approach for characterizing acetalated dextran derivatives using Raman spectroscopy combined with two-dimensional correlation spectroscopy (2D-COS). Traditional methods like 1 H-NMR spectroscopy rely on hydrolysis and are constrained by the time-sensitive detection of volatile acetone. Raman spectroscopy, as a non-destructive technique, was applied to analyze time-dependent acetalation of methoxy and ethoxy acetalated dextran derivatives (AcDex and AceDex). By employing 2D-COS, time-resolved Raman spectral changes revealed key marker bands associated with kinetic (acyclic) and thermodynamic (cyclic) substitution products. The observed Raman peak ratios corresponded well with those derived from 1 H-NMR spectroscopy, confirming the accuracy of the method. This approach not only eliminates the need for hydrolysis but also provides a robust, time-independent tool for tracking acetalation, enabling precise control over polymer properties. The findings underscore the potential for Raman spectroscopy in real-time monitoring and optimization of dextran-based polymer synthesis.