Absorption Spectrum of Vitamin A Concentrates

This is a continuation of the work previously reported by Woodrow and Cunningham (Phys. Rev., vol. 35, p. 125, Jan. 1930) on the absorption spectrum of several common sources of vitamin A. Through the kindness of Dr. Morton of the University of Liverpool, it has been possible to investigate the absorption spectra of much more concentrated sources of vitamin A. Slight changes which have been made in the arrangement of the photoelectric spectrophotometer have given more dependable results, partly because they have greatly reduced the destruction of the vitamin A by the ultra-violet light used in taking the measurements. Prominent bands have been found at 310 and 328 mµ. with minor bands at 323 and 340 mμ. The 328 mμ band was much stronger than the same band with weaker sources of vitamin A