Solvent-free mechanochemical preparation of graphene oxide-Fe3 O4 and its application in magnetic dispersive solid-phase extraction of illegal dyes in food samples.

A simple, green, and efficient mechanochemical approach was developed herein to prepare tunable magnetic graphene oxide nanoparticles. The obtained nanoparticles were successfully used as adsorbents in a magnetic dispersive solid-phase extraction method to extract three cationic dyes (i.e., thioflavine T, auramine-O, and basic orange 2) found in food samples. Our proposed approach also utilized high-performance liquid chromatography with ultraviolet detection. Several key variables affecting the extraction recovery were investigated. These included the sample pH, amount of extractant, extraction time, sample volume, elution solvent type and volume, and the stability and reusability of the magnetic graphene oxide nanoparticles. Under optimized conditions, the calibration curve was linear at a concentration range of 0.005-1.0 µg/mL with a correlation coefficient of 0.9992-0.9996. Moreover, the limits of detection were determined at 0.97-1.35 µg/mL. The extraction mechanism was investigated via ultraviolet-visible spectrophotometry and zeta-potential analyses. The developed method was used to analyze the above-mentioned cationic dyes in bean products and yellow fish samples. Notably, satisfactory spiked recoveries ranging from 90.7 to 104.9% were achieved.

Potential sources and sediment-pore water partitioning behaviors of emerging per/polyfluoroalkyl substances in the South Yellow Sea.

Emerging per/polyfluoroalkyl substances (PFASs) have received great concerns, but there are few data in the coastal environment, which play an essential role in their global transport. In this study, surface water and sediment samples were collected in the South Yellow Sea close to Jiangsu Province China, and 26 legacy as well as emerging PFASs were investigated. Perfluorooctanoic acid (PFOA) and perfluorobutane sulfonate (PFBS) were predominant in the coastal water of the South Yellow Sea with a relatively higher level than other coastal regions in the world. PFBS and 6:2 fuorotelomer sulfonic acid (6:2 FTSA) were two major alternatives of perfluorooctane sulfonate (PFOS) which were used in textile surface treatment and fire-fighting foams, respectively. Multiple receptor models identified that fluoropolymer manufacture, textile and food packages were three major sources of PFASs in the South Yellow Sea. The partitioning behaviors of PFASs between sediment and pore water in the marine environment were compared, and the partitioning coefficients of hexafluoropropylene oxide trimer acid (HFPO-TA) and 6:2 chlorinated polyfluorinated ether sulfonic acid (6:2 F-53B) were reported for the first time, which exhibited stronger partition in sediment than their predecessors. The results provide important hints to understand the environmental transport of PFASs in the marine environment.

Enhanced cytotoxicity of pentachlorophenol by perfluorooctane sulfonate or perfluorooctanoic acid in HepG2 cells.

Chlorinated phenols and perfluoroalkyl acids (PFAAs) are two kinds of pollutants which are widely present in the environment. Considering liver is the primary toxic target organ for these two groups of chemicals, it is interesting to evaluate the possible joint effects of them on liver. In this work, the combined toxicity of pentachlorophenol (PCP) and perfluorooctane sulfonate (PFOS) or perfluorooctanoic acid (PFOA) were investigated using HepG2 cells. The results indicated that PFOS and PFOA could strengthen PCP's hepatotoxicity. Further studies showed that rather than intensify the oxidative stress or promote the biotransformation of PCP, PFOS (or PFOA) might lead to strengthening of the oxidative phosphorylation uncoupling of PCP. By measuring the intracellular PCP concentration and the cell membrane properties, it was suggested that PFOS and PFOA could disrupt the plasma membrane and increase the membrane permeability. Thus, more cellular accessibility of PCP was induced when they were co-exposed to PCP and PFOS (or PFOA), leading to increased cytotoxicity. Further research is warranted to better understand the combined toxicity of PFAAs and other environmental pollutants.