the relative distributions , measured by high performance liquid chromatography , of 7 alpha- and 8 alpha-hydroxyriboflavin , riboflavin , and hydroxyethylflavin and its derivative were calculated to be 31.1 , 5.0 , 25.6 , 4.9 , and 21.9 % , respectively , to total flavins in normal human urine obtained in early morning .
C0035527
riboflavin
C0016213
flavins