Determination of riboflavin, flavin mononucleotide and flavin-adenine dinucleotide in wine and other beverages by high-performance liquid chromatography with fluorescence detection.

A new direct HPLC method with fluorescence detection has been developed for the routine analysis of riboflavin, flavin mononucleotide and flavin-adenine dinucleotide, in wines and other beverages. These compounds are the main agents responsible for the "taste of light" that some white wines and other beverages develop when they are exposed to the light, due to the formation of sulfur compounds that produce an anion/garlic odor. A Hewlett-Packard 1100 gradient liquid chromatograph with 1046A fluorescence detector was used. To improve the selectivity, each compound was monitored to fit the best lambda excitation/lambda emission (265/525 nm). A 500 nm cut-off filter was used. The column was a Hypersil C18 ODS, 200 x 2.1 mm, 5 microns particle size. The volume injected was 20 microliters. A constant flow-rate of 0.6 ml/min was used with two solvents: solvent A, 0.05 M buffer NaH2PO4 at pH = 3.0 with H3PO4 and solvent B, acetonitrile. The precision, linearity and sensitivity of this method have been established.