TLC DETERMINATION OF BIOTIN IN A LYOPHILIZED MULTIVITAMIN PREPARATION

A TLC method for the determination of biotin was developed. The method is selective and sensitive and permits the determination of biotin in the presence of all water‐soluble vitamins as well as glycine, edetate sodium, and methylparaben. The main steps are: dissolution of the lyophilized multivitamin preparation in water, addition of the internal standard, application on a thin‐layer plate, separation from interfering components, visualization by spraying with 4‐dimethylamir nocinnamaldehyde, and in situ determination by reflectance measurements. Spraying the plate with paraffin after the coloring procedure increases the sensitivity of the method. The coefficient of variation is 2.3% with 0.15 μg of biotin/spot. Quantities as low as 10 ng/spot can be determined. Copyright © 1979 Wiley‐Liss, Inc., A Wiley Company