Determination of biotin in foods by high-performance liquid chromatography with post-column derivatization and fluorimetric detection

A method to determine the content of biotin in various foods by reverse phase liquid chromatography is proposed and includes extraction of the vitamers (d-biotin and d-biocytin) by enzymatic hydrolysis (papain) and takadiastase if necessary, post-column derivatization by avidin-FITC (fluorescein 5-isothiocyanate) and fluorimetric detection of the complex obtained. Enzymatic hydrolysis is preferred to sulfuric acid hydrolysis because it does not induce any degradation of the vitamin and allows a good estimation of the bioavailable forms. The proposed method has a good recovery rate (90–106%), a satisfactory repeatability (coefficient of variation less than 7%) and a very low detection limit (0.005 μg g−1).