Desenvolvimento e validação de método para análise de parabenos e aplicação em águas superficiais do semiárido cearense por DLLME-HPLC-DAD

Abstract

Parabens are esters derived from 4-hydroxybenzoic acid often used as preservatives in medicines, foods and personal care products, due to their broad spectrum of antimicrobial activity, low cost and good chemical stability in these formulations. Studies have reported the influence of exposure to parabens on human health, including their possible estrogenic action. However, the assessment of the environmental aspects of this exposure, especially in aquatic ecosystems, is still scarce, with data reported in Brazil only a decade ago. In this work, a method for the determination of methyl, ethyl, propyl and butyl parabens in water was developed and validated to the quantification of these compounds in surface water. The dispersive liquid-liquid microextraction (DLLME) technique was used for extraction and pre-concentration of parabens coupled with high performance liquid chromatography with diode array detector (DLLME-HPLC-DAD) for quantification. Full factorial design 23 with central point was applied to optimize the extraction, with the variables: extraction solvent volumes, dispersion and sample volume. The statistical desirability function (D) was also applied. In the optimized results, acetone and decanol were selected as disperser/extraction solvents, respectively, for the volume 700 µL/90 µL, 10 mL of sample volume, with value D above 0.80 and pH between 5.0 and 6.0. The method exhibits good linearity, correlation coefficients (r) varying from 0.9957 to 0.9989, limits of detection (LOD) ranging from 0.5-1.0 μg L-1 and limits of quantification (LOQ) between 1.0-2.0 μg L-1. Recovery rates showed from 88-115%. The method was applied to determine parabens in water samples from 13 reservoirs (Ceará, Brazil), and all results were below the LOQ of the method. The Principal Component Analysis (PCA) showed the existence by 2 groups of variables with the greatest influence on the water quality: the physical-chemical and environmental, whose parameters are related to contamination by domestic sewage, constituting the main source of contamination of parabens in these water resources.