Decomposition of vitamin D by the hydroperoxide formed from 2,6-di-tert-butyl-4-methylphenol during alkali saponification.

When vitamin D2 was saponified with addition of BHT in an alkaline solution, the low recoveries were observed. These were confirmed to be due to the oxidation of vitamin D2 by 2, 6-di-tert-butyl-4-methyl-4-hydroperoxy-2, 5 -cyclohexadiene-1-one formed from BHT during alkali saponification. The de composition of vitamin D2 was protected by the addition of sufficient quantities of sodium ascorbate or erythorbate as an antioxidant before alkali saponifica tion because of preventing the formation of hydroperoxide from BHT. In the case of BHA, distinguishable decomposition of vitamin D2 was not observed during alkali saponification.