Simultaneous Determination of a Polychlorinated Dibenzo-p-Dioxin and Dibenzo-p-Furan in Environmental Water by Dispersive Liquid-Liquid Microextraction (DLLME) and a Modified QuEChERS Procedure with High-Performance Liquid Chromatography - Diode Array Detection (HPLC-DAD)

Polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) are persistent organic pollutants frequently detected in air, soil, and water. Thus, monitoring these compounds in environmental compartments is fundamental to identifying potential risks to human health. However, studies of analytical methods for PCDD/Fs extraction in water are still limited. Therefore, this study aimed to optimize and validate a dispersive liquid-liquid microextraction (DLLME) and QuEChERS method combined with high-performance liquid chromatography - diode array detection (HPLC-DAD) to determine 2,3,7,8-tetrachlorodibenzo-p-dioxin (2,3,7,8-TCDD) and 2,3,7,8-tetrachlorodibenzofuran (2,3,7,8-TCDF) in water samples. The proposed methods were optimized to achieve higher recovery rates for PCDD/Fs extraction. DLLME and QuEChERS combined with HPLC-DAD were validated according to SANTE guidelines to ensure reliability and applicability. The recoveries of both methods ranged from 93.5 to 105.5%, and relative standard deviations were less than 12%. The analytical validation certified that the proposed methods were selective, precise, accurate, and linear, with limits of quantification ranging from 2.4 to 5.3 mu g L-1. These results suggested the feasibility of DLLME and modified QuEChERS combined with HPLC-DAD as simple, inexpensive, and environmental-friendly approaches for monitoring PCDD/F in aqueous samples.