THERMOSPRAY AND ELECTROSPRAY MASS-SPECTROMETRY OF FLAVOCOENZYMES - ANALYSIS OF RIBOFLAVIN SULFATES FROM SUGAR-BEET

Thermospray (TSP) liquid chromatography mass spectrometry and electros pray (ESP) mass spectrometry were applied to the analysis of the flavo coenzymes riboflavin (Rfv), riboflavin 5'-monophosphate (FMN) and flav in adenine dinucleotide (FAD). Positive and negative ion spectra are p resented. TSP spectra of Rfv and FMN were characterized by the presenc e of intense and characteristic fragment ions containing the flavin ri ng whereas in those from FAD, ions containing the adenine moiety predo minate. ESP affords mainly molecular weight information as well as som e indication of the number of acidic places in these molecules. Applic ation of these techniques to the analysis of root extracts from iron-d epleted sugar beet (Beta vulgaris) was instrumental in the characteriz ation of two novel riboflavin compounds, riboflavin 3'-monosulphate (3 -FMS) and riboflavin 5'-monosulphate (5-FMS), as the major flavins in roots.