Fluorimetry riboflavin

Riboflavin is commonly determined fluorimetri-cally, for instance in milk, by its strong native fluorescence at pH 7, which arises from the extended conjugation and rigidity of the nonribose portion of the molecule. Another fluorimetric method involves conversion of riboflavin into its fluorescent derivative lumiflavin using ultraviolet (UV) irradiation. Mixtures of thiamin and riboflavin in foods such as cereal products have been resolved using LC with fluorimetric detection. 

Riboflavin Foods Flow injection method - fluorimetry... 

Riboflavin Ready-to-feed milk-based infant formula Fluorimetry... 

Yields refer to the proportion of riboflavin in the dried fungus. Concentrations in Calocybe and Lyophyllum were determined by UV/vis. spectrophotometry, those in Russula by fluorimetry. 

Fluorimetry is the standard technique for riboflavin analysis in food. 

Pharmaceutical preparations containing riboflavin have been analyzed by TLC using concentrated ethanolic extracts on silica gel plates developed in butanol-benzene-acetic acid-water (8 7 S 3) or butanol-acetic acid-water (9 4 5) (7). Foods, tissue samples and urine each require particular methods of sample preparation and these, together with a number of solvent systems have been reviewed (8). A darkroom is required for sample preparation and chromatography of flavins to prevent photolytic degradation. The fluorescent property of flavins provides a convenient means of detection and spots have been located under radiation at 254 and 366nm (4). HPTLC followed by fiberoptic fluorimetry has been used to quantitate riboflavin in vitamin mixtures and can detect 48-320 ng (6). Recently, a method has been described using mixed-layer plates of GDX-102 and silica gel G (1 1) precoated with hexadecyl-trimethylammonium bromide developed in 60-70% ethanol (9). 

As in thiamin determination, proposed methods for riboflavin are based on fluorimetry and HPLC. 

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