Low-wavenumber vibrational Raman optical activity of carbohydrates

A high optical density holographic notch filter in combination with a single-grating spectrograph was used to increase the spectral range for backscattered Raman optical activity (ROA) measurements of biological molecules in aqueous solution towards lower wavenumber. ROA spectra of D-galactose, D-maltose and laminarin starting at ca. 350 cm−1 are presented as first examples. An ROA couplet observed at 427 ± 10 cm−1 in the spectra of D-maltose, D-cellobiose and laminarin appears to reflect the configuration of glycosidic links in di- and poly-saccharides