Differentiation of Vitamins D₂ and D₃ by Infrared Spectrophotometry.

Corrections for Background in Spectrophotometry Using Difference-in-Absorbance Values. Application to Vitamin A.

“…In addition to the work with vitamin A, the AA ratio or index has other uses. This has been shown in previous applications in this laboratory (IS, 14)• In one of these instances (IS) the correlation between such an index and the quantities of vitamin D2 and D3 in a mixture obtained by chromatography was established by using AA values in the infrared.…”

“…Another approach to the general problem of background absorption is the graphically or mathematically elaborated base line technique (8,8,7,11,14, 80, 85). Davidow and Woodard (5) and Rotondaro (18) have provided excellent practical examples of this kind of correction.…”

Multifunctional hydroxyapatite and poly(d,l-lactide-co-glycolide) nanoparticles for the local delivery of cholecalciferol

“…The bands with maxima at 632 and 3567 cm −1 are caused by the vibrations of the hydroxyl group in the crystal lattice of HAp [30]. Cholecalciferol is typified by the CH 3 asymmetric stretching mode and the CH 2 symmetric stretching mode at 2943 and 2875 cm −1 , respectively [31,32], the two bands that are observable in our spectrum of the vitamin too. The spectrum of HAp/D 3 exhibits the most intensive bands of both HAp and cholecalciferol, indicating that the synthesized material is composed of HAp and cholecalciferol, as in accordance with the XRD results.…”

Gas Chromatographic Studies of Vitamins D2 and D3

“…One of the standard procedures involved extraction of vitamin D from saponified material, purification from interfering sterols, and final colorimetric quantitation using antimony trichloride as the chromogenic agent (8). Infrared spectrophotometry has also been used for the differentiation of vitamins D2 and D3 in feed concentrates (7). Recently, a study was 1 Present address, Department of Physiological Hygiene, University of Toronto, Toronto, Canada. 2 Present address, Research Institute, Hospital for Sick Children, Toronto, Canada.…”