Uso de carvão ativado magnético para extração em fase sólida de 2,4-diclorofenol em água e sua determinação por HPLC

Abstract

Sample preparation is a crucial step in the performance of a chemical analysis. It influences later steps such as accuracy, precision, repeatability, reproducibility of the results, total time and effort involved in the analysis, and therefore the cost. Among the different methods of sample preparation, magnetic solid phase extraction (MSPE) is a method in which magnetic sorbents are used, which aid both in the concentration of analytes and in the elimination of interferents. Furthermore,itcaneasily be removed from the matrix by using an external magnetic field. These materials consist of magnetic nanoparticles linked to different compounds such as silica, polymers, activated carbons, amine and OH groups, among others, responsible for their selectivity. Magnetic solid phase extraction can be employed for several types of analytesfrom the simplest to the most complex, among them 2,4-dichlorophenol (2,4-DCF). The 2,4-Dichlorophenolis an important compound used in the manufacture of pesticides and herbicides, and minimal concentrations of this compound can cause various types of disturbances for human, animal, and also the environment. Thus, the objective of this study was to synthesize an activated carbon/Fe3O4 composite to assist in the concentration of 2,4-dichlorophenol. Several characterizations were made, and the main experimental parameters of the extraction process such as mass of the composite, pH, sample volume, among others, were optimized, obtaining a high response to MSPE. The method was validated and showed recoveries greater than 50.0%. Subsequently, it was applied in samples of real water collected near plantations that make use of pesticides. The material presented adsorption properties of quick and easy removal of the reaction medium, besides being selective to the concentration of the analyte.