SISTEMA DE MULTICOMUTAÇÃO EM FLUXO PARA A DETERMINAÇÃO ESPECTROFOTOMÉTRICA DE ÁCIDO ACETILSALICILICO EM FÁRMACOS

Abstract

In this work was developed an analytical procedure employing multicommutation for the determination of acetylsalicylic acid in tablet. The procedure is based on the Trinder reation, wherein the salicylic acid from the hydrolysis of acetylsalicylic acid is reacted of iron (III), forming a purple complex, monitored spectrophotometrically at 525nm. The multicommutation developed system employed three solenoid valves for solution management and a peristaltic pump for the fluid propulsion, and spectrophotometric detection working in the visible range. The optimization of the proposed system have been made to study the carrier solution, flow rate, reactor, numbers of cycle, Trinder reagent concentration, studies of opening time of solenoid valves that opitmal values respectively. HNO₃ as carrier solution , 3.5 ml . minˉ¹ , 80cm , 12 cycles , 10 g.Lˉ¹, 0.1 s for the valve insert reagent and 0.5 s for the insertion of the sample valve.The system provided linear response: range between 25-100 mg.Lˉ¹ of AAS ( R = 0.999 ), with RSD 0.91% ( n = 4 ), good sampling frequency of 72 determination per hour. detection limit (LD) of 0.57 mg.Lˉ¹ and quantification limit (LQ) of 1.89 mg.Lˉ¹. The results obtained with recovery test ranged between 97 and 99%. In a comparison of methods, the test t of Student has not presented relevant difference, once the tcal. = 0,91 were smaller than ttab. = 2.78 at a 95% confidence level.