Desenvolvimento de sistemas de análise por injeção em fluxo para a determinação de peróxido de hidrogênio e cetoconazol

Abstract

In this dissertation presents the development of two different flow injection procedures with spectrophotometric detection for the determination of hydrogen peroxide and ketoconazole. The determination of hydrogen peroxide was determinate in commercial samples and UHT milk samples. For the determination of ketoconazole, we used samples pharmaceutical tablets. The flow system for determining hydrogen peroxide was optimized by monitoring spectrophotometrically the product of chemical reaction between the peroxide and ammonium metavanadate in an acid medium. The calibration curve showed linearity from 8.0×10-4 to 8.0×10-3 mol.L-1 and a limit detection of 2.4 × 10-4 mol.L-1 was obtained. Relative standard deviations lesser than 1.2% (n = 10) for hydrogen peroxide solutions with concentrations of 1.96×10-3 and 4.0×10-3 mol.L-1 were obtained. The analytical frequency of 60 determinations per hour was obtained. Another flow system has been proposed for the determination of ketoconazole. In this system, chemical reaction between the reagent cerium(IV) and ammonia nitrate and ketoconazole was monitored spectrophotometrically at 500 nm. The linearity of calibration curve between 6.0×10-5 and 9.5×10-5 mol.L-1 and the limit detection of 1.0×10-5 mol.L-1 were obtained. The relative standard deviations lesser than 4.5% (n = 10) for ketoconazole solutions with concentrations of 1.0×10-4 to 1.9× 10-4 mol.L-1 and analytical frequency of 60 determination per hour were obtained.