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• TAPA-TFPB-COFs was simply synthesized at room temperature. • TAPA-TFPB-COFs were explored as sorbents for the SPE of PCAs. • The established SPE-HPLC-MS/MS method was sensitive and accurate. • This method satisfied the analyzation of PCAs in environmental water samples. The determination of traces levels of pesticide residue in water is crucial for monitoring water quality. In this study, covalent organic frameworks (COFs), namely TAPA-TFPB-COFs were prepared at room temperature (25 °C) and applied as adsorbents for the solid phase extraction (SPE) of phenoxy carboxylic acid herbicides (PCAs). The extraction was followed by analyzation using liquid chromatography-tandem mass spectrometry (LC-MS/MS). Under the optimal conditions, ultrasensitive and specific analysis of PCAs in water samples was achieved. The method exhibited high sensitivity with low limits of detection (0.08–0.28 ng L−1), good linearity in the range of 1.00 to 200 ng L−1 and satisfactory repeatability (intra-day: 3.72–5.30%; inter-day: 2.02–4.04%). The method was successfully applied to the analyzation of trace PCAs in tap, well, and river water and the spiked recoveries were in the range of 81.1–112%. These results indicate that the SPE-LC-MS/MS technique with TAPA-TFPB-COFs as the SPE adsorbent is a promising technique for the detection of trace levels of PCAs in environmental water samples. [ABSTRACT FROM AUTHOR]

• Effective dual-emission CDs were synthesized via reasonable surface regulation. • The ratiometric sensing system for TNP was constructed based on DE-CDs. • Successfully realized the detection of TNP in tap and pond water samples. • The feasibility of biological application was verified by cell imaging experiment. Carbon dots (CDs) with dual emission property can provide a convenient way to construct a ratiometric fluorescent sensor, which contributes to accurate determination of the target analytes. In this work, we present a simple and effective route to prepare dual emission CDs (DE-CDs) through the solvothermal reaction of o-phenylenediamine and ethanolamine. Under the excitation of UV light, DE-CDs not only show two distinguishable fluorescent emission peaks (430 nm, 550 nm), but also exhibit good water solubility and ratio fluorescence stability. The synthesized DE-CDs were employed as a ratiometric fluorescent sensor for the sensitive and selective detection of 2,4,6-trinitrophenol (TNP). Under optimal analysis conditions, a good linear relationship was obtained with the TNP concentration range from 0.2 to 50 µM and the limit of detection can reach 50 nM. The proposed method was applied successfully for the TNP detection in real water samples with recoveries of 86.8–116.3%. Furthermore, cell imaging experiments confirm the feasibility of visualizing intracellular TNP in live HeLa cells. [ABSTRACT FROM AUTHOR]

In this study, a stable cadmium(II)-based metal-organic framework (MOF) material was designed and used as a sorbent for the dispersive solid-phase extraction ( d SPE) of polybrominated diphenyl ethers (PBDEs) in environmental water samples. Gas chromatography coupled with triple quadrupole mass spectrometer (GC–MS/MS), working in the negative chemical ionization mode, was used to quantify the target analytes. Characterization of the material was performed by Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), powder X-ray diffraction (PXRD), elementary analyses (EA) and thermogravimetric analyses (TGA). The synthesized rod shape MOF is on the micro level in size and has excellent chemical and solvent stability. The extraction conditions, including the extraction time, temperature and ionic strength, were examined systematically using response surface methodology (RSM). Under optimized conditions, the method that was developed showed an excellent extraction performance. Good linearity ( R 2 > 0.99) within the concentration range of 0.25–250 ng L −1 was obtained. Low limits of detection (0.08–0.15 ng L −1 , signal-to-noise ratio = 3:1) and good precision (relative standard deviation <12%, n = 6) were achieved. The developed method was applied to analyze natural and spiked environmental water samples. [ABSTRACT FROM AUTHOR]

[Display omitted] • Atomic copper (I)-carbon nitride (Cu-CN) was constructed. • Cu-CN exhibits peroxidase-mimic catalysis and colloidal stability. • Cu-CN can detect PFOS selectively in the range of 0.07–3 μM with LOD of 14.9 nM. • Coordination effect and fluorophilic interaction are the detection mechanism. • Cu-CN detection platform can detect PFOS in real water samples with RSD ≤ 8.37%. Pursuing a selective and stable optical sensor for the reliable detection of perfluorooctane sulfonate (PFOS) is critical to controlling and reducing the risk of exposure to human. Here, we elaborately prepared an atomic copper(I)-carbon nitride (Cu-CN) peroxidase-mimic catalyst and therefore developed a reliable and accessible PFOS detection method. Well-distributed Cu(I) atoms are exclusively anchored within CN nanosized matrix as identified Cu-CN single-site active centers. Benefiting from the high peroxidase-mimic catalytic capability and colloidal stability, Cu-CN exhibits outstanding detection of PFOS selectively in the range of 0.07 to 3 μM coupled with the detection limit of 14.9 nM. The occupation of atomic Cu(I) specific catalytic sites caused by strong PFOS coordination and the fluorophilic interaction between PFOS should be responsible for the damping of TMB oxidation. Moreover, this detection platform was also used successfully to detect PFOS in three real water samples with RSD ≤ 8.37%. This well-established colorimetric sensing system based on peroxidase-mimic capability of single-atom catalyst is promising for the detection of other hazards in aquatic environment. [ABSTRACT FROM AUTHOR]

Boron nitride hollow spheres with ultrathin-shells were synthesized and used as sorbents for dispersive solid-phase extraction of aromatic pollutants at trace levels from environmental water samples. Polychlorinated biphenyls (PCBs) were selected as target compounds. Sample quantification and detection were performed by gas chromatography–tandem mass spectrometry. Extraction parameters influencing the extraction efficiency were optimized through response surface methodology using the Box–Behnken design. The proposed method achieved good linearity within the concentration range of 0.15–250 ng L −1 PCBs, low limits of detection (0.04–0.09 ng L −1 , S/N = 3:1), good repeatability of the extractions (relative standard deviation, <12%, n = 6), and satisfactory recoveries between 84.9% and 101.0% under optimal conditions. Real environmental samples collected from rivers, local lakes, rain and spring waters were analyzed using the developed method. Results demonstrated that the hexagonal boron nitride-based material has significant potential as a sorbent for organic pollutant extraction from environmental water samples. [ABSTRACT FROM AUTHOR]

• Asp-AuNPs were successfully synthesized by simple one-pot protocol. • The colorimetric sensing system of Cr3+ was constructed based on Asp-AuNPs. • Successful detection of Cr3+ in practical water samples was carried out. • Scanometric analysis was established to be suitable for Cr3+ field detection. In this work, we report an effective one-pot strategy for synthesizing aspartic acid-functionalized gold nanoparticles (Asp-AuNPs) and constructing chromium (III) ion (Cr3+) colorimetric sensing system. Aspartic acid, acting as a reductant and stabilizer, was used directly to synthesize functionalized AuNPs without additional surface modification procedure. The Asp-AuNPs possesses the same good stability and optical properties as citrate-stabilized AuNPs, which become a new option for preparing AuNPs. More importantly, aspartic acid exhibits superior performance than citrate and other succinic acid derivatives because of its Cr3+ identifying property. The Asp-AuNPs was used for the sensitive and selective detection of Cr3+ based on the aggregation-induced color change of AuNPs from wine red to blue-gray. Under optimal conditions, the absorbance ratios (A 660 nm /A 520 nm) show good linearity with Cr3+ concentrations with a limit of detection of 0.6 nM. Furthermore, the proposed method was applied for the analysis of Cr3+ in environmental water samples successfully with a reliable recovery of 95.4%-105.1%. Besides, the scanometric analysis model based on three primary colors change was established to deal with the requirement for the rapid quantitative determination of Cr3+ in environmental emergencies. [ABSTRACT FROM AUTHOR]