Determination of aqueous bisphenol A and tetrabromobisphenol A using molecular-complex-based liquid-liquid microextraction

Tetrabromobisphenol A biotransformation in aged soil: Mechanism analysis induced by root exudates during rhizoremediation of Helianthus annus

Rhizoremediation, recognized as a progressive strategy for the removal of organic pollutants in soil, prominently focused on the influence of root exudates-induced alterations within the rhizosphere on the bioavailability and transformation of pollutants. However, the influence of root exudates on the ultimate fate of tetrabromobisphenol A (TBBPA) in soil remains unclear. The current study embarked on a comprehensive examination of the biotransformation process and underlying mechanisms of TBBPA driven by root exudates of Helianthus annus in rhizospheric soil. The pot experiment underscored the constructive impact of root exudates on enhancing the TBBPA dissipation efficiency within lab-controlled, with the increments of 18.77 %∼38.64 %. The core bacterial players responsible for TBBPA biotransformation were identified, with the prominent genus being Saccharibacteria_genera_incertae_sedis, unclassified_Sphingomonadaceae, and Parcubacteria_genera_incertae_sedis. In rhizospheric soil, a comprehensive analysis disclosed the presence of 20 different biotransformation products of TBBPA. Notably, root exudates were found to predominantly drive the reductive debromination pathway. This study provided for the first concrete evidence that root exudates can promote the desorption of TBBPA from soils. The current study aimed to decipher the molecular mechanisms in biotransformation process of TBBPA mediated by root exudates, and also provided reference for the environmental behavior of organic pollutants induced by root exudates.

Determination of tetrabromobisphenol A and its brominated derivatives in water, sediment and soil by high performance liquid chromatography-tandem mass spectrometry

Tetrabromobisphenol A (TBBPA) was typical brominated flame retardant and potential environmental endocrine disruptor, and it had persistence, bioaccumulation and chronic toxicity. Simultaneous determination of ultra-trace TBBPA, tribromobiphenol A (tri-BBPA), dibromobiphenol A (di-BBPA), monobromobisphenol A (mono-BBPA) and bisphenol A (BPA) was developed by high performance liquid chromatography-tandem mass spectrometry(HPLC-MS/MS), the parent ion charge ratios (m/z) had been optimized. The linear range was wider and the limit of detection was (LOD) 0.09 ~ 0.21 ng mL-1, which could detect trace pollutants. The extraction efficiency was improved by optimizing the parameters, HLB cartridge was used in the water sample by solid phase extraction (SPE), the recovery rates in water samples were over 80.28% with three concentration levels, the relative standard deviations (RSD) were less than 7.12%, and the minimum detection limit of the method was 0.90 ~ 2.10 × 10-3 ng mL-1. Soil and sediment samples were extracted by accelerated solvent extraction (ASE), the recovery rates in soil and sediment were over 79.40% and 75.65%, the minimum detection limit was 0.0225 ~ 0.0525 ng g-1, RSD was less than 7.19%. The proffered method was successfully utilized to detect actual samples, the residue of di-BBPA and mono-BBPA are detected in Naihe River and Shuxi River in Tai'an City, residue of di-BBPA and mono-BBPA was detected in the soil, and there was low residual amount of di-BBPA, mono-BBPA and BPA in the sediment of Shuxi River.

Analysis of tetrabromobisphenol A and bisphenol A in plant sample-method optimization and identification of the derivatives

Tetrabromobisphenol A (TBBPA) is the most abundant brominated flame retardant and bisphenol A (BPA) is often identified as the metabolic product of TBBPA. Both of them are highly bioconcentrated and show serious biological toxicity. In this study, an analytical method was optimized to simultaneously determine TBBPA and BPA in plant samples. Moreover, the uptake and metabolism of TBBPA in maize were investigated through hydroponic exposure experiment. The whole analysis procedure included ultrasonic extraction, lipid removal, purification by solid-phase extraction cartridge, derivatization, and detection by GC/MS. Optimizations were conducted for each pretreatment step above. After improvement, methyl tert-butyl ether (MTBE) was chosen as the extraction solvent; the lipid removal was conducted by repartition between organic solvent and alkaline solution. The best suitable pH condition is 2-2.5 for the inorganic solvent before used for further purification by HLB and silica column with the optimized elute solvent of acetone and mixtures of acetone and hexane (1:1), respectively. The recoveries of TBBPA and BPA spiked in maize samples were 69±4% and 66±4% with the relative standard deviation less than 5%, respectively, for the entire treatment procedure. Limits of detections were 4.10 ng/g and 0.13 ng/g for TBBPA and BPA in plant samples, respectively. In the hydroponic exposure experiment (100 μg/L, 15 d), the concentrations of TBBPA in maize cultivated in pH 5.8 and pH 7.0 Hoagland solutions were 1.45 and 0.89 μg/g in roots and 8.45 and 6.34 ng/g in stems, while they were all below the detection limit for leaves, respectively. The distribution of TBBPA in different tissues was as the following order: root>>stem>leaf, illustrating the accumulation in the root and the translocation to the stem. The uptake variations under different pH conditions were attributed to the change of TBBPA species, now that it shows greater hydrophobicity at lower pH condition as a kind of ionic organic contaminant. Monobromobisphenol A and dibromobisphenol A were identified as metabolisms products of TBBPA in maize. The efficiency and simplicity of the method that we proposed characterize its potential application as a screening tool for environmental monitoring and contribute to a comprehensive study of the environmental behavior of TBBPA.

Thoughtful design of a covalent organic framework with tailor-made polarity and pore size for the enrichment of bisphenols and their derivatives: Extraction performance, adsorption mechanism and toxicity evaluation

A stable, reusable and cost-effective covalent organic framework (COF) with medium polarity was successfully decorated on Fe₃O₄. The Fe₃O₄@COF contained tailor-made polarity and pore size that fitted well with bisphenols and their derivatives (BPs). When coupling magnetic solid-phase extraction (MSPE) with high-performance liquid chromatography (HPLC) detection, the Fe₃O₄@COF featured efficient recognition and enrichment for BPs due to π-π stacking, C-H⋯π interactions, pore-filling effect, dispersion force and hydrophobic interactions. Under optimized conditions, calibration plots exhibited good linearity (5-1000 ng mL^-1), and limits of detection (LOD) ranged from 0.15 to 0.39 ng mL^-1. The method was successfully employed in quantifying BPs in authentic lake and river water samples with satisfactory recoveries ranging from 81.4% to 120%. Molecular dynamics simulation revealed extraction mechanisms, and a microscopic behavior related to the clustering property of the emerging brominated compounds was first discovered. Ecotoxicological assessments of target pollutants were conducted from multiple aspects, highlighting the harmfulness of the chemicals and the significance of the analytical method. The proposed methodology offered sensitive detection and quantification, which was beneficial for the timely tracking of the concentration, transportation and distribution of BPs to better explore their environmental behavior and tackle contamination problems in complex environmental matrices.

A Review on Tetrabromobisphenol A: Human Biomonitoring, Toxicity, Detection and Treatment in the Environment

Tetrabromobisphenol A (TBBPA) is a known endocrine disruptor employed in a range of consumer products and has been predominantly found in different environments through industrial processes and in human samples. In this review, we aimed to summarize published scientific evidence on human biomonitoring, toxic effects and mode of action of TBBPA in humans. Interestingly, an overview of various pretreatment methods, emerging detection methods, and treatment methods was elucidated. Studies on exposure routes in humans, a combination of detection methods, adsorbent-based treatments and degradation of TBBPA are in the preliminary phase and have several limitations. Therefore, in-depth studies on these subjects should be considered to enhance the accurate body load of non-invasive matrix, external exposure levels, optimal design of combined detection techniques, and degrading technology of TBBPA. Overall, this review will improve the scientific comprehension of TBBPA in humans as well as the environment, and the breakthrough for treating waste products containing TBBPA.

Rapid analysis of forchlorfenuron in fruits using molecular complex-based dispersive liquid-liquid microextraction

The main sample preparation method for analysis of pesticide residues in fruits is QuEChERS. In this study, a novel sample preparation method using molecular complex-based dispersive liquid-liquid microextraction is introduced with detection of forchlorfenuron by high-performance liquid chromatography coupled with diode array and mass spectrometric detection. Sample treatment involves initial extraction of a 5 g sample with 3 mL acetonitrile, and then the selective concentration of the analyte is performed using 150 µL tributyl phosphate by forming intermolecular hydrogen bonds with the analyte. The extraction mechanism was proved using ATR-FTIR. Under the optimised conditions, recovery rates varied between 88% and 107% for various sample matrices spiked at three levels in the range 0.01-0.1 mg kg^-1. Intra-day and inter-day repeatabilities were in the ranges of 2.2-8.0% and 1.6-9.5%, respectively. Detection limit and quantitation limit were 0.33 µg kg^-1 and 1.09 µg kg^-1 for diode-array detection; 0.01 µg kg^-1 and 0.04 µg kg^-1 for tandem mass spectrometry detection. This method was successfully applied for the analysis of 149 various fruits. The analyte was found in 4 of the 149 samples and the contents were not over the specific maximum residue limit established by domestic and international regulations.

Synthesis of magnetic metal organic framework/covalent organic framework hybrid materials as adsorbents for magnetic solid-phase extraction of four endocrine-disrupting chemicals from milk samples

RATIONALE

Endocrine-disrupting chemicals (EDCs), widespread and easily ingested through the simple food chain, have been suggested to pose potential carcinogenic threats to human health. Considering food safety and public health, it is urgent to establish a sensitive and effective method to enrich and determine EDCs in food samples.

METHODS

Novel hybrid nanocomposites Fe₃ O₄ @A-TpBD@NH₂ -MIL-125(Ti) were synthesized through the formation of amide bonds. The as-prepared Fe₃ O₄ were innovatively encapsulated with 4-aminobenzoic acid functionalized COF(A-TpBD) to generate bare carboxyl (-COOH), which formed amide bonds with the NH₂ -MIL-125(Ti), generating well-defined and hierarchical hybrid materials. The Fe₃ O₄ @A-TpBD@NH₂ -MIL-125(Ti) materials were used as the adsorbents for magnetic solid-phase extraction (MSPE) coupled with high-performance liquid chromatography/tandem mass spectrometry (HPLC/MS/MS) to enrich and determine EDCs (E1, E2, E3 and BPA) from milk samples.

RESULTS

Fe₃ O₄ @A-TpBD@NH₂ -MIL-125(Ti) exhibited improved adsorption efficiency and selectivity based on π-π stacking interaction, hydrogen bonding, electrostatic interaction, and the interaction between the hydroxyl group in EDCs and titanium ions (IV, [Ti]⁴⁺ ). Under the optimized conditions, Fe₃ O₄ @A-TpBD@NH₂ -MIL-125(Ti)-based MSPE coupled with HPLC/MS/MS showed good linearity with correlation coefficient (R² ) ≥0.9983 and high sensitivity with limits of detection (LODs) in the range of 0.37-0.85 μg/L. Moreover, the developed method was successfully employed to detect EDCs in milk samples.

CONCLUSIONS

Fe₃ O₄ @A-TpBD@NH₂ -MIL-125(Ti) possess good adsorption capability and selectivity for EDCs. In addition, the proposed MSPE-HPLC/MS/MS method based on Fe₃ O₄ @A-TpBD@NH₂ -MIL-125(Ti) is effective and sensitive for the determination of EDCs in real samples, which can be used as a robust alternative method to monitor EDCs in complex matrices.