Abstract
The fluorometric assay of niacinamide described in our previous paper could be applied multivitamin preparations by removing thiamine and surface active agents. Riboflavin, vitamin B_6,folic acid and ascorbic acid did not disturb the determination. Thiamine could be removed by Fullers' earth, and the surface active agents which were added to make fat-soluble vitamins soluble could be extracted with chloroform. Recovery of niacinamide quantity in commercial preparations was practically 100% in this method.
