Determination of biotin in foodstuffs and pharmaceutical preparations using a biosensing system based on the streptavidin-biotin interaction

An affinity biosensor system for the determination of biotin and its deriva tives based on the specific non-covalent interaction between biotin and str eptavidin is described. The permanent immobilisation of streptavidin on con trolled-pore-glass (CPG) provides an adequate active support in which the s pecific and competitive reaction between biotin derivatives and biotin labe lled with peroxidase (POD) takes place. Biotin was used as a model. The dev elopment of this competitive assay was revealed by determining the amount o f POD which is not retained in the active support by using a derivatising r eaction with fluorimetric detection. The method exhibits a linear range fro m 0.1 to 8.0 mug l(-1) of biotin (r(2) = 0.9986, n = 9) with a precision, e xpressed as R.S.D., lower than 3.8% and a sampling frequency of 10h(-1). Th e approach has been applied to the determination of biotin in natural juice s and pharmaceutical preparations with recoveries ranging between 88.1 and 104.8%. (C) 2001 Elsevier Science B.V. All rights reserved.