FLUORESCENCE-BASED FLOW-INJECTION DETERMINATION OF BIOTIN AND BIOTINYLATED COMPOUNDS

A homogeneous fluorophore-linked binding assay for biotin and biotin-c ontaining compounds has been used in a merging-zone flow-injection sys tem. Analyses were first conducted by taking advantage of the enhancem ent in fluorescence intensity of a conjugate of avidin-fluorescein in the presence of biotin or biotin derivatives. Detection limits for bio tin as low as 2 x 10(-9) M could be achieved. A greater enhancement of fluorescence was found for a streptavidin-fluorescein conjugate. Cali bration curves obtained by using the streptavidin conjugate are shown for the determination of various biotinylated compounds in the flow-in jection system and in a batch mode.