Rapid determination of riboflavin in yeast preparations by reaction with silver ions

Abstract

A spectrophotometric method involving reaction with silver ions is proposed for the determination of riboflavin in yeast. The riboflavin is extracted by autoclaving in hot water and the co-extracted proteins are precipitated with 5-sulphosalicylic acid. The reproducibility of the method is 2.7% for 104 µg g^–1 of riboflavin and the detection limit is 2.8 µg g^–1. The composition and conditional stability constant of the silver-riboflavin complex have been determined as C₁₇H₂₀O₆N₄Ag.H₂O and log 5.82 (pH 7), respectively.