Spectrographic studies on the antimony trichloride reaction for vitamin A

Abstract

As mentioned in the first part of these studies [Notevarp & Weedon, 1936], the ratio between the two absorption bands of the antimony trichloride reaction for vitamin A is normally almost constant for potent preparations, but varies within wide limits for cod liver oils of usual potencies.Mittelmann [1925; 1927], in publications reviewed by Bezssonoff [1929], claimed to have prepared cod liver oils giving no blue colour until some oxidation had taken place. Hawk [1929] obtained some increase in the blue value on exposure of cod liver oils to air. Lovern et al. [1931] were not able to prepare oils giving no reaction, but found a considerable rise in the 603 m,u band on oxidation of very fresh oils. The 572 m, band remained approximately constant; this was confirmed by Heilbron et al. [1931]. We demonstrated earlier that very high concentrations of oil inhibited the 603 my band, but not the 572 m,u band, in fresh oils in which the 572 mp band predominated.

Chemistry of glycerol dichlorohydrin as a reagent for the determination of vitamin A

“…Some early studies of the antimony trichloride reaction with oils (163,164,243) showed that the color was not pro portional to the concentration of vitamin A; however, re sults obtained with the nonsaponifiable fraction gave a more linear relationship (40,206,242)* These values checked reasonably well with the biological method (40,107,206)* Much of the early spectrographic data concerning the color developed by reaction of vitamin A with antimony tri chloride has been reviewed by Munsell (153). Under suitable conditions it was found that the absorption at certain wave lengths were altered by changing concentration, temperature or by adding certain chemicals (19,55,145,165). It is now quite generally agreed that vitamin A in any of its forms possesses a single strong absorption band at 620…”

“…The presence In natiiral products of substances which in terfere vith the measurement of the antimony trichloride-vi tamin A color has been recognized by a number of workers (12,18,35,42,54,65,81,155,165,166,173,178).…”