A simple solid phase spectrofluorimetric method combined with flow analysis for the rapid determination of salicylamide and salicylic acid in pharmaceutical samples

A new, sensitive and very simple spectrofluorimetric biparameter sensor is described for the determination of salicylamide and/or salicylic acid in ph armaceutical preparations. The method integrates the transitory retention a nd fluorescence detection of both compounds on Sephadex QAE A-25 resin pack ed into a conventional flow-through cell. A monochannel manifold with two a lternative carriers is used. At pH 2.0 (first carrier) salicylic acid is se lectively retained on the solid support and after developing the analytical signal it is desorbed. At pH 11.0 (second carrier) both salicylic acid and salicylamide are simultaneously and transitorily retained on the solid, th e analytical signal now corresponding to both analytes. The monochromators were tuned at 260 (excitation) and 415 (emission) nm, respectively. The cal ibration graph for salicylamide is linear over the range 0.01 to 0.32 mu g mL(-1) and for salicylic acid from 0.04 to 1.0 mu g mL(-1) in the presence of each other. The relative standard deviation and the sampling frequency f or the determination of salicylamide (0.20 mu g mL(-1)) and salicylic acid (0.50 mu g mL(-1)) were 1.1% and 35 h(-1), and 0.9% and 45 h(-1), respectiv ely. Good results on application to individual determination or mixture res olution in pharmaceutical samples testify to the usefulness of the proposed sensor.