Uso da espectrofluorimetria como técnica aliada à microextração líquido-líquido dispersiva e ao monitoramento da degradação por ozonólise do ibuprofeno

Abstract

Micropollutants emerging are compounds that have been found in very low quantities in the environment and, in many cases, have a tendency to accumulate. There are not yet sufficient knowledge about all its effects, although there are indications that they may be a source of public health risks and the various biological systems related to them. In this compounds class drugs and their metabolites are founded which have emission source as waste generated by human action. In this sense, several studies have reported the presence of ibuprofen, an important non-steroidal anti-inflammatory drug with analgesic and antipyretic properties in media such as water rivers and streams from water treatment plants. It is necessary therefore the development of simple and fast analytical procedures capable of identifying and quantify theses micropollutants. On the hand, it is necessary to consider the diversity of chemical composition of sample matrices involved in this type of analysis. Thus, this paper proposed the optimization of sample preparation procedure for liquid-liquid microextration dispersive by employing a factorial design 23, in which we evaluated the volumes influence of hydrochloric acid 2.0 mol disperser solvent, acetone, and extractor solvent, dichloromethane added. For quantification of ibuprofen was used spectrofluorimetric procedure, which had its parameters evaluated and adjusted for analytical application. It was proposed the use of proposed developed procedure for also monitoring the degradation of ibuprofen, by ozonolysis in a basic medium. The sulfamethoxazole degradation was monitored to compare its behavior. An analytical curve with the concentration range of ibuprofen between 1.58x10-6 e 1.73x10-5 molL'I was obtained and can be described by equation I= 3.39x106(±7.3x104) x [IBU] —1.64 (0.88), where I is the intensity of emission and [IBU] is the concentration of ibuprofen, the regression coefficient (r) od 0.998 to limit detection and quantitation of 8.77x10-7 e 2.92x le mol L-', respectively and standard deviation of 0.95. The conditions established using the factorial design 23 were volumes of 1.0 mL of hydrochloric acid 2.0 mol L-I, 0.5 mL of dichloromethane and 1.0 mL of acetone to the procedures of sample preparation technique, from which were obtained enrichment factors of 67-99% and recovery to 69,2%. Finally, it has been found for ibuprofen low degradation, however it was observed indicating the formation of degradation products with similar excitation and emission characteristics of the ibuprofen. Moreover, it was found most degradation of sulfamethoxazole, besides, no effects were observed excitation and emission, resulting from degradation products, making possible the monitoring of their degradation by the proposed technique.