A sensitive fluorescence optosensor for analysing propranolol in pharmaceutical preparations and a test for its control in urine in sport

Abstract

We describe a simple and selective method for analysing propranolol and a sensitive test for its control in urine. A flow-through fluorescence optosensor based on on-line immobilization in a non-ionic-exchanger (Amberlite XAD-7) solid support in a continuous flow was used in both cases. Determination was made in 5 mM H 2PO 4 −/HPO 4 2− buffer solution at pH 6 at a working temperature of 20 °C. Fluorescence intensities were measured at λ ex/em=300/338 nm with a response time of 80 s, thus obtaining a linear concentration range of between 0 and 250.0 ng ml −1 with a detection limit of 1.3 ng ml −1, an analytical sensitivity of 6.0 ng ml −1 and a standard deviation of 2.40% at a 150 ng ml −1 concentration level for propranolol. We also propose a test to detect propranolol in urine with a linear concentration range between 0 and 100.0 ng ml −1, a detection limit of 0.2 ng ml −1, an analytical sensitivity of 1.0 ng ml −1, and a standard deviation of 0.84% at a 75 ng ml −1 concentration level. The effect of proteins presents in urine samples were evaluated. The two proposed methods were satisfactorily applied to commercial formulations and urine samples respectively.