730 



VIT. VITAMINS A 



TABLE 12 

 Absorption" Maxima and Extinction Coefficients of Vitamin A Preparations in 



Various Solvents 



" J. R. Loofbourow, Vitamins and Hormones, 1, 109-155 (1943). 

 >> N. D. Embree, Ann. Rev. Biochem., 16, 323-358 (1947). 

 <= R. A. Morton, Ann. Rev. Biochem., 11, 365-390 (1942). 



>> J. G. Baxter and C. D. Robeson, J. Am. Chem. Soc, 64, 2407-2410 (1942). 

 « T. H. Mead, S. W. F. Underbill, and K. H. Coward, Biochem. J., 33, 589-600 (1939). 

 / C. D. Robeson and J. G. Baxter, Nature, 15-5, 300 (1945); ./. Am. Chem. Soc, 69, 

 136-141 (1947). 

 « E. M. Shantz, Science, 108, 417-419 (1948). 



SO far as the purity of the vitamin A was concerned; the potency of the 

 oil in International units per gram was calculated by multiplying the 

 extinction value at 328 mix by a conversion factor of 2000.'" 



225 First specified in contract form No. PDP 76 for vitamin oils and concentrates 

 issued bv the War Food Administration in 1944. 



