A comparison of two methods for the determination of vitamin a with special reference to the effects of storage time, storage temperature and light on the vitamin a content of plasma 

The destructive-irradiation technique and the Carr-Price method for the determination of vitamin A were compared. No significant difference could be found between the two methods with regard to repeatability and percentage recovery of vitamin A. Exposure to light at room temperature for  a period of up to 8 hours after sampling had no influence on the vitamin A content of plasma.  Plasma could be stored up to 14 days at a temperature of -20°C without any loss of vitamin A.