Carbon Dot-Decorated Graphite Carbon Nitride Composites for Enhanced Solid-Phase Microextraction of Chlorobenzenes from Water

In this work, carbon dot-decorated graphite carbon nitride composites (CDs/g-C₃N₄) were synthesized and innovatively used as a SPME coating for the sensitive determination of chlorobenzenes (CBs) from water samples, coupled with gas chromatography-mass spectrometry. The CDs/g-C₃N₄ coating presented superior extraction performance in comparison to pristine g-C₃N₄, owing to the enhancement of active groups by CDs. The extraction capacities of as-prepared SPME coatings are higher than those of commercial coatings due to the functions of nitrogen-containing and oxygen-containing group binding, π-π stacking, and hydrophobic interactions. Under optimized conditions, the proposed method exhibits a wide linearity range (0.25-2500 ng L^-1), extremely low detection of limits (0.002-0.086 ng L^-1), and excellent precision, with relative standard deviations of 5.3-9.7% for a single fiber and 7.5-12.6% for five fibers. Finally, the proposed method was successfully applied for the analysis of CBs from real river water samples, with spiked recoveries ranging from 73.4 to 109.1%. This study developed a novel and efficient SPME coating material for extracting organic pollutants from environmental samples.

Core-shell structured Fe2O3/CeO2@MnO2 microspheres with abundant surface oxygen for sensitive solid-phase microextraction of polycyclic aromatic hydrocarbons from water

Core-shell structured Fe₂O₃/CeO₂@MnO₂ microspheres were fabricated and used as solid-phase microextraction coating for determination of polycyclic aromatic hydrocarbons (PAHs) in water samples. XPS spectra demonstrated the generation of abundant surface oxygen on Fe₂O₃/CeO₂@MnO₂ microspheres, which provided binding sites for enhancement of analyte extraction. Under optimized conditions, the proposed method presented good linearity in the concentration range 0.04-100 ng mL^-1, with low limits of detection varying from 0.38 to 3.57 ng L^-1 for eight PAHs. Relative standard deviations for a single fiber and five batches of fibers were in the ranges of 4.1-8.2% and 7.1-11.4%, respectively. The proposed method was successfully used for determination of PAHs in real river water samples with recoveries ranging from 87.1 to 115.9%. The proposed method using as-prepared Fe₂O₃/CeO₂@MnO₂ microspheres as SPME coating exhibit significant potential for real sample analysis due to its excellent reproducibility, high sensitivity, and good linearity.

Novel copper sulfide doped titania nanoparticles as a robust fiber coating for solid-phase microextraction for determination of polycyclic aromatic hydrocarbons

Immobilized TiO₂ nanoparticles modified by nanoscale CuS (CuS@TiO₂NPs) were successfully synthesized and used as fibers for solid-phase microextraction (SPME) for the determination of some polycyclic aromatic hydrocarbons (PAHs) in water samples. A novel fiber has been developed by postprecipitation of CuS coated the titania nanoparticles in situ grown on a titanium wire annealed at 550 °C in a nitrogen ambient atmosphere. Its morphology and surface properties were characterized by scanning electron microscopy and energy dispersive X-ray spectrometry. It was connected to high performance liquid chromatography-ultraviolet detector (HPLC-UV) equipment by replacing the sample loop of a six-port injection valve, building the online SPME-HPLC-UV system. Variables affecting extraction procedures, including desorption time, stirring speed, extraction temperature, extraction time and ionic strength were investigated and the parameters were optimized. The SPME fiber exhibits high selectivity for the five PAHs studied. The linear ranges varied between 0.15 μg L⁻¹ and 200 μg L⁻¹ with correlation coefficients ranging from 0.9913 to 0.9985. LODs and LOQs ranged from 0.02–0.04 μg L⁻¹ and 0.07–0.13 μg L⁻¹. RSDs for one fiber and fiber-to-fiber were in the range of 3.2–4.3% and 4.6–6.8%, respectively. Additionally, the fiber possessed advantages such as resistance to organic solvent, high mechanical strength and difficult breakage, making it have strong potential applications in the selective extraction of PAHs from complex water samples at trace levels.

Immobilized TiO₂ nanoparticles modified by nanoscale CuS (CuS@TiO₂NPs) were successfully synthesized and used as fibers for solid-phase microextraction (SPME) for the determination of some polycyclic aromatic hydrocarbons (PAHs) in water samples.

Electrospun polyamide/graphene oxide/polypyrrole composite nanofibers: an efficient sorbent for headspace solid phase microextraction of methamphetamine in urine samples followed by GC-MS analysis

A novel polyamide/graphene oxide/polypyrrole nanofiber was fabricated with the aid of the electrospinning technique and applied in headspace solid phase microextraction.