A flow-through optosensing device with fluorimetric transduction for rapidand sensitive determination of dipyridamole in pharmaceuticals and human plasma

A flow-through optosensor with fluorimetric transduction has been prepared for the sensitive and selective determination of dipyridamole in aqueous so lutions and biological fluids. The method is based on a monochannel flow-in jection analysis system using Sephadex QAE A-25 resin, placed into a Hellma 176-QS fluorimetric flow-through cell, as an active sorbing substrate. The native fluorescence of dipyridamole fixed on the solid sorbent is continuo usly monitored at wavelengths of 305 and 490 nm for excitation and emission , respectively. After obtaining the maximum fluorescence intensity, the elu ent solution (KH2PO4/NaOH buffer solution, c(T)=0.05 mol 1(-1), pH 6.0) is allowed to reach the flow cell, the analyte is removed, and the resin suppo rt is regenerated. When an NaOH (10(-4) mol 1(-1))/NaCl (0.1 mol 1(-1)) sol ution is used as carrier solution, at a flow-rate of 1.56 mi min(-1), the s ensor responds linearly in the measuring range of 10-500 mu -g 1(-1) with a detection limit of 0.94 mug 1(-1) and a throughput of 22 samples per hour (300 mul of sample volume). The relative standard deviation for ten indepen dent determinations (200 mug 1(-1)) is less than 0.82%. The method was sati sfactorily applied to the determination of dipyridamole in pharmaceutical p reparations and human plasma. (C) 2001 Elsevier Science B.V. All rights res erved.