RESUMO
There exists a high demand for fast, simple, and reliable methodologies for determining the presence of organochlorine pesticides (OCPs) on environmental samples. Moreover, the toxicity and accumulation of potential OCPs in several environments have led to the development of technologies that achieve their removal from contaminated waters. In this study, a novel method combining a dispersive liquid-liquid microextraction procedure based on the solidification of floating organic drop is developed and validated for the extraction, preconcentration, and determination of 10 OCPs: α-BHC, p,p'-DDE, δ-BHC, dieldrin, p,p'-DDT, endosulfan I, endosulfan sulfate, heptachlor, heptachlor epoxide (isomer B), and methoxychlor in water samples. The results show that the calibration curves were linear for all the studied compounds, and the coefficients of correlation higher than 0.99. The variation coefficient for precision and accuracy was lower than 10%, and the accuracy ranged from 93 to 105%. Low limit of detection and limit of quantification values ranging from 0.06-3.00 ng mL-1 and 0.20-10 ng mL-1 were obtained, respectively. The capability of the proposed method was confirmed using an analysis of the water samples before and after the degradation process; this was achieved by employing nanomaterials, while performing an analysis of 160 real samples that were sourced from a Brazilian river. A cobalt-doped magnetite was applied for the environmental remediation of the studied compounds, and it was verified that the novel material has the potential to be used in environmental remediation with a degradation efficiency exceeding 80% for the majority of the studied compounds.