Insight into the interaction of tetrabromobisphenol A with sediment-derived dissolved organic carbon in a multiphase system by direct immersion solid phase microextraction

Tetrabromobisphenol A (TBBPA), a ubiquitously used commercial brominated flame retardant (BFR), has been widely detected in aquatic environments, and has aroused much attention due to its potential adverse effects on aquatic organisms. However, current research on the environmental fate and transport of TBBPA in the sediment–dissolved organic carbon (DOC)–water polyphase system is lacking. In this study, the sorption behavior of TBBPA in a water–DOC–sediment system was investigated using the direct-immersion solid-phase microextraction (DI-SPME) method, and the free dissolved concentration (Cw-SPME) and DOC adsorption concentration (CDOC) of TBBPA in water were measured by applying this DI-SPME approach. In addition, the effects of pH, ionic strength, and soluble organic concentration on the adsorption of TBBPA in the multiphase system were evaluated. The adsorption kinetics experimental results show that the adsorption behavior of TBBPA on sediments conforms to a linear model, suggesting that it could be mainly absorbed by sediments. The solid–water partition coefficient (Kd) of TBBPA was artificially reduced 1.54 times using the traditional liquid–liquid extraction method because the sorption behavior of the DOC was ignored, which could be accurately corrected using the DI-SPME method. The logKd and logKOC of TBBPA in the multiphase system were 4.12 ± 0.25 and 6.48 ± 0.25, respectively. Finally, the interference experiment revealed that the sorption behavior of TBBPA was affected by the pH, ionic strength (calcium ion), and humic acid concentration, apart from the lead ion concentration itself.