Desenvolvimento de procedimentos espectrofluorimétricos para a determinação de cetoconazol e TBHQ em amostras de interesse ambiental, alimentício e farmacêuticos

Abstract

This work deals with the development analytical procedure for determination of Ketoconazole and TBHQ employing molecular spectrofluorimetry in samples of environmental, food and pharmaceuticals interests. These procedures developed do not use toxic reagents, in which it is only necessary the use of ethanol, as well as HCl 0.10 mol L-1 and surfactant for extraction and determination steps, respectively. The results indicated the dependence of emission signal with king of the surfactant and its concentration. The best conditions were obtained with Cetyltrimethylammonium Bromide at pH 8.80. A linear analytical curve until 1.01x10-4 mol L-1 of ketoconazole (r = 0.99) and a detection limit of 1.83x10-7 mol L-1 were obtained. The procedure was validated studying the recovery of ketoconazole in pharmaceutical and environmental samples. The recovery values between 76.0 to 98.1 % for water and 93.8 to 103% for pharmaceutical formulations were obtained. The results obtained on the determination of ketoconazole in pharmaceutical formulations were compared with results obtained by comparative UV-Vis procedure, where no difference at 95% confidence level was found. In development of procedure for determination of TBHQ in samples food, a factorial design 22 was employed for determination of optimum conditions of sensitivity, evaluating the main effects and interaction factors of each variable. In the optimized conditions, the analytical curve was linear in 1.02x10-6 to 2.56x10-5 mol L-1 (r = 0.9999) and a detection limit of 8.37x10-8 mol L-1 was obtained. The developed procedure was employed for determination of TBHQ in vegetable cream, margarine, mayonnaise and vegetable oil. Recovery of 84.7 to 109% were obtained for these samples. The procedure was easy to apply without the need of laborious sample preparation step.