[Spectrophotometric determination of riboflavin-5'-monophosphate and flavin-adenin-dinucleotide after chromatographic separation on column (author's transl)].

Riboflavin-5'-monophosphate and flavin-adenin-dinucleotide have been determined spectrophotometrically at 450 nm, after separation by column chromatography on Sephadex anion exchanger. Elution was obtained with a continuous concave gradient of ammonium formate, pH 5.0. The technique employed allows good resolution of the two substances and the identification of the impurities of commercial samples of FMN. Such impurities were identified as free riboflavin, di-, tri- and poly-phosphate esters of riboflavin and a compound that has been tentatively identified as cyclic riboflavin-2', 3'-monophosphate.