Study of ergocalciferol and cholecalciferol (Vitamin D): Modeled optical properties and optical detection using absorption and Raman spectroscopy

The task of assembling and calculating spectrally significant lines of Vitamin D2 and D3 is related to a wider goal of establishing if it is possible to develop non-invasive optical sensors for these substances present at concentrations on the order of tens of nmol/L. Such a non-invasive in vivo sensor would be helpful for medical considerations, among others, related to multiple sclerosis prevention, reduced risk of mortality in D3-treated acute in-patients admitted with COVID 19, systemic infection, acute respiratory tract infections, including epidemic influenza, community-acquired pneumonia at concentrations <50nmol/L (<20ng/mL), dental health (90-100nmol/L) of 25(OH) D, general health and others. Currently, to determine the concentration of these substances, it is necessary to draw a sample from a vein in ambulatory settings and analyse the sample with the gold standard of mass spectroscopy or immunoassay. In this article Vitamin D optical properties are studied by density functional theory calculations, compared to reported data, and the new calculated and measured D2 and D3 optical absorption lines are presented, as well as the calculations compared with spectral measurements of optical transmission, FTIR ATR and Raman spectra.