Development of a NiFe2O4 covalent organic framework based magnetic solid-phase extraction approach for specific capture of quinolones in animal innards prior to UHPLC-Q-Orbitrap HRMS detection.

This study aimed to present a selective and effective method for analyzing quinolones (QNs) in food matrix. Herein, a NiFe2O4-based magnetic sodium disulfonate covalent organic framework (NiFe2O4/COF) was prepared using a simple solvent-free grinding method, and was adopted as a selective adsorbent for magnetic solid phase extraction of QNs. Coupled with UHPLC-Q-Orbitrap HRMS, an efficient method for simultaneous detection of 18 kinds of QNs was established. The method exhibited good linearity (0.01-100 ng g-1), high sensitivity (LODs ranging from 0.0011 to 0.0652 ng g-1) and precision (RSDs below 9.5%). Successful extraction of QNs from liver and kidney samples was achieved with satisfactory recoveries ranging from 82.2% to 108.4%. The abundant sulfonate functional groups on NiFe2O4/COF facilitated strong affinity to QNs through electrostatic and hydrogen bonding interactions. The proposed method provides a new idea for the extraction of contaminants with target selectivity.

Fabrication and Adsorption Optimization of Novel Magnetic Core-shell Chitosan/Graphene Oxide/ß-cyclodextrin Composite Materials for Bisphenols in Aqueous Solutions.

A novel magnetic composite material, Fe3O4@SiO2/chitosan/graphene oxide/ß-cyclodextrin (MCGC), was prepared by multi-step methods. Various methods were used to systematically characterize the morphology, composition, structure, and magnetic properties of MCGC. The results obtained show that the composite material has good morphology and crystal structure and can be separated quickly by an external magnetic field. The operation is relatively easy, and the raw materials used to prepare this material are economical, easy to obtain, and environmentally friendly. The performance and adsorption mechanism for using this material as an adsorbent to remove bisphenol A (BPA) and bisphenol F (BPF) from water were studied. The adsorption parameters were optimized. Under optimal conditions, MCGC was found to remove more than 90% of BPA and BPF in a mixed solution (20 mg/L, 50 mL); the adsorption process for BPA and BPF on MCGC was found to follow a Redlich-Peterson isotherm model and Pseudo-second-order kinetic model. The adsorption mechanism for MCGC may involve a combination of various forces. Recycling experiments showed that after five uses, MCGC retained a more than 80% removal effect for BPA and BPF, and through real sample verification, MCGC can be used for wastewater treatment. Therefore, MCGC is economical, environmentally friendly, and easy to separate and collect, and has suitable stability and broad application prospects.

Residual levels and risk assessment of tetrabromobisphenol A in Baiyang Lake and Fuhe river, China.

Tetrabromobisphenol A (TBBPA) in water from Xiongan New Area was determined by gas chromatography-mass spectrometry (GC-MS), simultaneous with its risk assessment. The optimal extraction conditions, derivatization factors (such as derivation reagent amount, derivatization time and temperature), and dissolution solvent were determined by orthogonal experiment. These results indicated the optimum derivatization time and temperature were 70 °C and 30 min, respectively, whilst the amount of derivatization reagent (N,O-bis (trimethylsilyl) trifluoroacetamide) was 40 µL. The optimum extraction efficiency was obtained when using the mixture of hexane-dichloromethane (1:1, v:v) with salt concentration of 6 g/L. Using the sample of S9 as control, the recovery experiments were performed with three different spiked levels. The water samples of Baiyang Lake and Fuhe river were analyzed using the optimized conditions. Those results showed that the concentrations of TBBPA in samples ranged from 18.5 ng/L to 82.6 ng/L, which lies in the middle level of data previously published from other areas in China. The risk quotient (RQ) model was used to evaluate the above data. The results of exposure and risk assessment showed that the margin of exposure (MOE) was 1.28 × 107-2.5 × 107 and the RQmax was 0.0266. The European Food Safety Authority (EFSA) standard and categories of RQ indicates that the estimated dietary exposure to TBBPA is unlikely to raise significant health concerns. This is the first report on the occurrence and risk assessment of TBBPA in waters from Xiongan New Area, which will be helpful for further risk assessment of other persistent organic pollutants. At present, the toxicological data of TBBPA in the biological body of Baiyang Lake is limited. In addition, more accurate and convenient approaches for the risk assessment of TBBPA should be explored.