Abstract: The method utilizes sequential immobilized enzyme reactors to first hydrolyse β-D-glucosides to β-D-glucose (using β-glucosidase) and then to produce H2O2 from bet-D-glucose (using glucose oxidase); the H2O2 is detected by the luminol chemiluminescence reaction. Individual β-D-glucosides were determined in a flow injection system in which samples were injected into a stream of 1 mM phosphate buffer (pH 6.5) containing 0 to 30% of acetonitrile (1.5 mL min-1). A mixture of glucosides was analyzed in an HPLC flow system; separations were performed on a column (25 cm x 4.6 mm) of Zorbax ODS (5 µm) fitted with a silica pre-column and a Partisil ODS-2 guard column, with 1 mM phosphate buffer (pH 6.5) containing 25% of acetonitrile as mobile phase (1.0 mL min-1). Chromatographic detection limits were ~0.1 µM (2 pmol) with a rectilinear working range of >3 decades.