Fluorometric Method Autoclave in 0.1 N HCl for 30 min Adjust pH to isoelectric point to precipitate proteins Filter Determination: Test Tubes 10 ml sample, + 1 ml of riboflavin standard or 1 ml H2O + 1 ml acetic acid, + 0.5 ml KMnO4 (4%) + 0.5 ml 3% H2O2 - KMnO4 color should disappear in 10 seconds, + 20 mg powdered Na2S2O4 Calculation mg Riboflavin/ml Final Sample Solution [F(sample) - F(blank)] x 0.1 x 0.001 F(sample + standard) - F(sample) =Fluorometric Method Autoclave in 0.1 N HCl for 30 min Adjust pH to isoelectric point to precipitate proteins Filter Determination: Test Tubes 10 ml sample, + 1 ml of riboflavin standard or 1 ml H2O + 1 ml acetic acid, + 0.5 ml KMnO4 (4%) + 0.5 ml 3% H2O2 - KMnO4 color should disappear in 10 seconds, + 20 mg powdered Na2S2O4 Calculation mg Riboflavin/ml Final Sample Solution [F(sample) - F(blank)] x 0.1 x 0.001 F(sample + standard) - F(sample) =