Methods for assessment of vitamin B₂

Although riboflavin (vitamin B₂) was initially isolated as a yellow-green pigment from milk whey in 1872; it was not until the 20th century, when research on accessory factors began, that scientists started to investigate the nature of this pigment further. Riboflavin is fluorescent under ultraviolet light and in pure form is a yellow crystalline solid that is poorly soluble in comparison to the other B vitamins. Riboflavin is the precursor to the essential coenzymes flavin mononucleotide (FMN), and flavin adenine dinucleotide (FAD). Flavin mononucleotide and FAD are called flavocoenzymes and the enzymes that require their presence to function are termed flavoproteins. Riboflavin cannot be synthesized in humans and is not stored in the body so ongoing adequate dietary intake is required to maintain the cellular concentrations of FMN and FAD at an appropriate level. A wide variety of assays have been described for the measurement of vitamin B₂ in pharmaceutical products and in food and drink. A much more limited range of techniques are available for the analysis of riboflavin in body fluids.