Structure analysis of ascorbic acid using near-infrared spectroscopy and generalized two-dimensional correlation spectroscopy

Ascorbic acid was investigated by FT-NIR (Fourier transform near-infrared) spectroscopy and generalized two-dimensional (2D) correlation spectroscopy. The FT-NIR spectra were measured over a temperature range of 30–130 °C. Combined near-infrared spectroscopy and generalized 2D correlation spectroscopy, the molecular structure (especially the hydrogen bond) was analyzed, four kinds of intermolecular hydrogen bond and two kinds of intramolecular hydrogen bond of ascorbic acid were elucidated, the bands of ascorbic acid were assigned. The results will be helpful to the understanding of ascorbic acid and utility of this substance.