SIMULTANEOUS DETERMINATION OF ATENOLOL, PROPRANOLOL, DIPYRIDAMOLE ANDAMILORIDE BY MEANS OF NONLINEAR VARIABLE-ANGLE SYNCHRONOUS FLUORESCENCE SPECTROMETRY

First derivative non-linear variable-angle synchronous fluorescence sp ectrometry has been developed to improve the selectivity fluorescence measurements without loss of sensitivity. It allows the rapid simultan eous determination of different substances in a mixture from a single spectrum based on a single scan. This method was applied for the simul taneous determination of atenolol (ATE), propranolol (PRO), amiloride (AMI) and dipyridamole (DIP) at concentrations between 10-400, 6-200, 5.6-280 and 5-100 ng ml(-1), respectively, by means of absolute Values of first derivative of non-linear variable-angle synchronous scan at lambda(ex)/lambda(em)=228.8/300, 287.2/340, 366.4/412.8 and 288/487.2 nm for ATE, PRO, AMI and DIP, respectively. In order to obtain maximum sensitivity and an adequate selectivity, factors affecting fluorescen ce intensity were studied. As a result, the analyses were performed in an ethanol-water (70%(v/v)) medium at a pH 7.5, adjusted by using tri shydroxymethyl amino methane (0.08 M) as a buffer solution. Analytical parameters of the proposed method were calculated according to the er ror propagation theory. The sensitivity, repeatability, reproducibilit y and limit of detection achieved with the proposed method are adequat e for the determination of these doping substances. (C) 1998 Elsevier Science B.V. AII rights reserved.