Search

International audience; AbstractGold nanoparticles (AuNPs) represent an attractive inorganic matrix for laser desorption/ionization mass spectrometry (LDI-MS) detection of low-molecular-weight analytes; however, their direct use is hindered by severe aggregation. To limit AuNPs aggregation, hexagonal boron nitride nanosheets (h-BNNs) were employed as supports to improve their desorption/ionization efficiency. Thus, Au@BN was synthesized and systematically characterized. It showed low background noise and high sensitivity for LDI-MS of fipronil and its metabolites. Au@BN-assisted LDI-MS was validated using complex samples including blueberry juice, green tea beverage, and fish muscle, achieving low detection limits (0.05–0.20 µg·L−1 for liquid media, 0.82–1.25 ng·g−1 for fish muscle), wide linear ranges (0.2–100 µg·L−1 for liquid media, 3.00–1000 ng·g−1 for fish muscle), high reproducibility (7.55%–13.7%), and satisfactory recoveries (82.62%–109.1%). Furthermore, spatial distributions of analytes in strawberries and zebrafish were successfully imaged. This strategy allows for the quantitative analysis of other small molecules in complex substrates.

Water stable Zr-metal–organic framework nanoparticles (PCN-224 NPs) have been solvothermally synthesized. PCN-224 NPs show spherical shape with smooth surface and particle size of approximately 200 nm. PCN-224 NPs can be stable in acid and aqueous solutions, as confirmed by powder X-ray diffraction. Gatifloxacin (GTF) adsorption measurements showed that PCN-224 NPs exhibit a high adsorption capacity of 876 mgg-1. Meanwhile, the adsorption factors, adsorption characteristics, and mechanisms of GTF were investigated in batch adsorption experiments.

Fiber coating is a key part of solid-phase microextraction (SPME) technology, and it determines the selectivity, sensitivity, and reproducibility of the analytical method. A ketoenamine covalent organic framework called Tp-Azo-COF with rich electronegative N atoms was prepared as an SPME coating in this work. The Tp-Azo-COF coating had a large surface area of 1218 m2 g-1 and good thermal and chemical stability, and it was applied for the extraction of organochlorine pesticides (OCPs). According to quantum chemistry calculations, the adsorption affinity of the Tp-Azo-COF coating for five OCPs was primarily affected by the halogen bond and hydrophobicity interaction. The extraction efficiencies of the Tp-Azo-COF coating for five OCPs were higher than those of three commercial SPME fiber coatings, and the enrichment factors ranged from 1061 to 3693. When combined with gas chromatography-tandem mass spectrometry, a wide linear range (0.1-1000 ng L-1), low limits of detection (0.002-0.08 ng L-1), and good fiber-to-fiber accuracy (4.3-10.9%) were achieved under optimal conditions. Moreover, the applicability of the developed method was evaluated by analyzing four samples (milk, green tea, tap water, and well water), and the recoveries were in the range of 83.4-101.6%, with relative standard deviations

An ionic covalent organic framework (Fe3O4@EB-TFB-iCOF) as a polar adsorbent was synthesized and characterized. It was applied in the magnetic solid phase extraction (MSPE) of four polar organic acids, namely, 2-(2,4,5-trichlorophenoxy)propionic acid, 2-methyl-4-chlorophenoxy acetic acid, naphthyloxyacetic acid, and naphthylacetic acid. The organic acids were detected by high performance liquid chromatography-ultraviolet analysis (HPLC-UV). A method for the determination of organic acids based on MSPE-HPLC-UV was established. The method shows good linear regression (R2≥ 0.9950), high precision (1.53-3.80%, n = 6), and low detection limit (0.10-0.49 ng mL-1). The recovery rate of environmental water samples ranges from 73.3% to 101.0%. This method provides a possibility for high sensitivity analysis of polar organic acids.

Perfluorinated alkyl substances (PFASs) are persistent, toxic, ubiquitously distributed, and bioaccumulated substances, which have attracted increasing concern. To investigate the environmental effects of PFASs, there is a need to develop a sensitive, rapid, and efficient method for detecting trace level PFASs. In this study, a conjugated microporous polymer (CMP) with loading of fluorine, fabricated by Sonogashira-Hagihara cross-coupling, was exploited as a solid-phase extraction (SPE) adsorbent. The prepared fluorine-functionalized CMP (FCMP), which showed a large surface area of 1089 m

The facile fabrication of covalent organic frameworks (COFs) is significant for exploring and promoting their application. In this study, TAPA-TFPB-COFs with flower-shaped morphology, good crystallinity, and high surface area was prepared via a facile room-temperature method. The as-synthesized TAPA-TFPB-COFs exhibited great adsorption capacity towards quinolone antibiotics (QAs) and satisfying reusability. Utilizing the TAPA-TFPB-COFs as solid-phase extraction cartridge packing and liquid chromatography-tandem mass spectrometry as detector, a reliable and ultrasensitive method for the assay of QAs was developed. The linearity ranges of QAs extended from 0.5 to 200 ng L−1 with correlation coefficients higher than 0.9974, and the limits of detection varied from 0.02 to 0.11 ng L−1. The intra-day and inter-day precision were lower than 10.8% and 6.7%, respectively. The applicability of the developed method was evaluated through analyzing of tap water, spring water, chicken, and fish samples. The recoveries of QAs in spiked water and food samples varied from 80.0% to 107.6%. The reliability of the developed method was further verified by the accurate detection of QAs in a fish certified reference material.

Covalent organic frameworks with tunable porous crystallinity and outstanding stability have recently exhibited fascinating pretreatment performance as solid-phase microextraction coatings. In this report, a β-ketoenamine-linked covalent organic framework (TpPa-1) was successfully constructed through a Schiff-base-type reaction between 1,3,5-triformylphloroglucinol (Tp) and para-phenylenediamine (Pa-1). A TpPa-1 coating was then fabricated on a stainless-steel fiber for capturing trace synthetic musks. This TpPa-1 coating exhibited strong interaction with synthetic musks because of its hydrophobicity and π–π affinity. This TpPa-1-based solid-phase microextraction methodology, coupled with gas chromatography-tandem mass spectrometry, provided high enrichment factors (1214–12 487), wide linearity (0.5–1000 ng L−1), low limits of detection (0.04–0.31 ng L−1), and acceptable reproducibility (relative standard deviation

This study synthesized a conjugated microporous polymer (CMP) at room temperature, which has high surface area, large conjugate system, and nitrogen-rich features. The material was explored as a solid-phase extraction (SPE) column, and it showed a higher extraction efficiency for nitro-musks compared to most commercial columns. Under optimal SPE conditions, a sensitive and efficient method for determining five nitro-musks was established based on gas chromatography-mass spectrometry (GC-MS). The method showed excellent linearity (R

The consumption of famciclovir (FCV) has been increased dramatically since the outbreak of coronavirus in 2019, and the pollution and harm of FCV in waters are concerned. Here, by utilizing aryl halides on 2, 4, 6-tris(4-bromophenyl)- 1, 3, 5-triazine (BPT) and primary amine groups on benzidine (BZ), a novel conjugated microporous polymer, namely BPT-BZ-CMP, was synthesized by Buchwald-Hartwig coupling reaction and applied in the removal of FCV from aqueous solution firstly. The synthesized BPT-BZ-CMP were characterized by various methods, including FTIR, SEM, BET, and Zeta-potential. Due to the micropore structure and high specific surface area, it took only 30 min for BPT-BZ-CMP to adsorb FCV to reach an equilibrium, and the maximum adsorption capacity was 347.8 mg·g

Chloroquine phosphate (CQP) has been suggested as an important and effective clinical reliever medication for the 2019 coronavirus (COVID-19). Nevertheless, its excessive use will inevitably cause irreparable damage to the entire ecosystem, thereby posing a considerable environmental safety concern. Hence, the development of highly-efficient methods of removing CQP from water pollution sources

Composite adsorbents based on metal-organic frameworks (MOFs) are excellent candidates for solid-phase extraction (SPE) due to their diverse chemical functionality and multilevel porosity. MOF superstructures based on self-assembly at room temperature (RT) could have less energy consumption and easier manipulation due to the larger complex geometry. The π-π stacking of the benzene ring could not only enhance the interaction toward hydrophobic or plane-structured targets but also be expected to promote the formation of the MOF superstructure. In this work, in the established RT self-assembly synthesis system, several factors were investigated to see how to obtain functional MOF superstructures with a regular geometry, among which the number of benzene rings in the ligand was mainly tested for its impact on self-assembly and adsorption capacity. By means of adsorption experiments and computational fluid dynamics (CFD) simulation, the relationship between structure and activity (SARs) was further explored. Interestingly, the MOF unit with the lowest specific surface area performed the best in adsorption. Then, the selected functional MOF superstructure and ionic liquid were used to produce the composite paper membrane facilely applied in the SPE device. After optimization of the preparation conditions and operation parameters, the established SPE-HPLC-UV method could selectively analyze tetracycline-like antibiotics in the range of 16.6-833.3 ng/g (ppb) in a meat sample. This work provided an RT synthesis method to produce a microsize MOF superstructure, with experimental and theoretical insights into the SARs, which could be expanded in the design of other MOF-based SPE composite membranes toward one group of analogues.

Efficient capture of benzoylurea insecticide (BU) residue in food is a vital procedure for food safe monitoring. Herein, a core-shell structured magnetic fluorinated covalent organic framework with good magnetic responsiveness and abundant fluorine affinity sites was successfully synthesized, suitable for magnetic solid-phase extraction (MSPE) of BUs. Using a room-temperature synthesis strategy, the magnetic fluorinated covalent organic framework was fabricated by in situ polymerization of 1,3,5-tris(4-aminophenyl) triazine (TAPT) and 2,3,5,6-tetrafluoroterephthaldehyde (TFTA) on the surface of carboxylated Fe3O4 nanoparticles. The competitive adsorption experiment and molecular simulation verified that this magnetic fluorinated covalent organic framework possesses favorable adsorption affinity for BUs. This magnetic fluorinated covalent organic framework could be easily regenerated and reused at least eight times with no reduction of enrichment performance. Combining this magnetic fluorinated covalent organic framework-based MSPE with high-performance liquid chromatography-tandem mass spectrometry, a novel sensitive method for the analysis of BUs was developed. In yellow wine and fruit juice samples, good linear correlations were obtained for BUs in the range of 10-2000 and 20-4000 ng·L-1, respectively. The limit of quantitation of the BUs ranged from 1.4 to 13.3 ng·L-1 in the two beverage matrices. Desirable precision was achieved, with intraday and interday relative standard deviations lower than 11%.

High-efficiency caption of pesticide residue is of vital significance for environmental safety monitoring. Herein, a hexagonal boron nitride nanosheets-based magnetic composite (Fe

High-performance extraction of polar phenols from aqueous samples is challenging because of their hydrophilicity, extremely low concentration, and complicated matrices. Covalent organic frameworks (COFs) are new types of porous organic materials. In this work, spherical TPB-DMTP-COF was fabricated via a simple room-temperature solution-phase approach. The material exhibited high acid/base stability, remarkable thermostability, high crystallinity, and large surface area of 1560 m2 g−1 and thus could be an excellent coating for solid-phase microextraction (SPME) of phenols. This coating provided superior adsorption affinity toward phenols over commercial coatings. TPB-DMTP-coated fiber showed high enhancement factors (EFs, 1741–4265), and EFs increased with the number of chlorine or methyl substituents and high hydrophobicity of phenols. Hence, the strong adsorption affinity could be derived from hydrophobic and steric hindrance effects together with π−π affinity, H-bonding, van der Waals forces, and size-matching effect. The proposed approach based on TPB-DMTP-COF-coated fiber and gas chromatography-tandem mass spectrometry achieved low limits of detection (0.0048–0.015 ng L−1), wide linearity (0.05–1000 ng L−1), good precision (

High-performance capturing polar phenoxycarboxylic acids herbicides (PCAs) from water samples remains a great challenge because PCAs form salt easily and dissolve. Polyphenylene-based conjugated microporous polymers (PP-CMPs), a fascinating type of polymers, bear π-conjugation over 3D polyphenylene scaffolds, inherent micropore, and large surface area, which are essential for capturing trace PCAs in complex samples. This work developed a novel approach to quantify trace PCAs using PP-CMPs as an efficient dispersive solid-phase extraction (d-SPE) adsorbent. The developed method based on PP-CMPs achieved high sensitivity with limits of detection of 0.55–3.84 ng L−1, satisfactory correlation coefficients (≥ 0.9912), good linearity (50–10,000 ng L−1), and good precisions (2.0–9.0%). Moreover, this method was used for simultaneous monitoring of the amounts of five PCAs in environmental water samples with satisfactory spiked recoveries (86.9–101.3%). All these fact demonstrated that this new d-SPE technique based on PP-CMPs exhibited a promising potential for highly sensitive analysis of trace PCAs in complex samples.

Quinolone antibiotic residues may pose potential threat to human health. A rapid and sensitive method was developed for the determination of quinolone residues in human serum and urine. After solid phase extraction (SPE) process, eight quinolone residues were analyzed by high-performance liquid chromatography/tandem mass spectrometry (HPLC-MS/MS) using ciprofloxacin-d8 as the internal standard. The relative standard deviation of intra-day and inter-day precision for the eight quinolones were less than 7.52% and the accuracies ranged from 95.8% to 103% in human serum, and from 94.1% to 104% in human urine. The extraction recoveries for the eight quinolones varied from 80.2% to 113% in human serum and 83.4% to 117% in human urine. The limit of detection for the eight quinolones was 0.50–1.00 ng/mL. Quinolone antibiotic residues in human serum and urine from 12 volunteers were successfully analyzed with the validated method. The SPE-HPLC-MS/MS method was useful for accurate determination of quinolone antibiotic residues in human body.

A composite material that comprised metal-organic nanotubes (MONTs) and a sponge, Cu-MONTs-sponge, was synthesized by using a rapid and convenient surfactant-assisted dip-coating method and used as a high-performance adsorbent for the solid-phase extraction of pharmaceuticals and personal care products (PPCP) from environmental water samples. By adjusting the surfactant concentration, a composite material that contained metal-organic nanotubes and a macroporous 3D porous sponge was constructed. This modified sponge achieved outstanding reproducibility as an adsorbent, with the adsorption of trace or ultratrace amounts of contaminants. Moreover, this composite material was conveniently recycled and its extraction efficiency only decreased by 6.3-12.1 % after 30 adsorption/desorption cycles. The resulting composite exhibited excellent adsorption capacity for PPCPs, which was attributed to its unique porous structure, natural hydrophobicity, and electrostatic interactions between the metal-organic nanotubes and analyte molecules. This Cu-MONTs-sponge material is an ideal adsorbent for the extraction of trace amounts of PPCPs from environmental water samples.

Fe2+-H2O2 Fenton system is the most applied system in advanced oxidation process for water remediation, but the drawbacks of acidic pH, sludge generation and poor regeneration are serious problems to overcome. Herein, we reported the Fe3O4/TiO2/reduced graphene oxide composites (RGO) as high-performance Fenton-like catalyst that could catalyze the decomposition of H2O2 in near neutral pH range of 5–9 for the decoloration of dye methylene blue (MB). The high catalytic activity of Fe3O4/TiO2/RGO was reflected by the fast absorbance decrease and chemical oxidation demand removal of MB solution within 20 min. The oxidation of MB was due to the radical generation in the Fe3O4/TiO2/RGO-H2O2 system, and the radicals could oxidize MB before the scavenging by the radical scavenger t-butanol. Higher Fe3O4/TiO2/RGO amount, H2O2 concentration and temperature accelerated the decoloration of MB. Fe3O4/TiO2/RGO could be easily regenerated by washing with water/ethanol mixture. The implication to the applications of Fe3O4/TiO2/RGO in water treatment is discussed.

Covalent organic frameworks (COFs) via Schiff base-type linkages (1,3,5-triformylphloroglucinol–paraphenylenediamine, TpPa-1), as an ideal coating, possesses significant potential for solid-phase microextraction (SPME) due to their fascinating properties, such as outstanding thermal and chemical stabilities, inherent porosity, and high crystallinity. A novel SPME device was fabricated based on TpPa-1 as an enrichment coating for capturing trace polybrominated diphenyl ethers (PBDEs). This TpPa-1 coating exhibited a superior enrichment capacity in “catching” PBDEs over commercial SPME fibers. Such performance is attributed to multiple factors, including the coating’s hydrophobic nature, π-π stacked architectures, large specific surface area, high thermal stability, and size-matching effect. High enhancement factors of 2035–6859, low detection limits of 0.0058–0.022 ng L−1, satisfactory linear range of 0.01–100 ng L−1, good repeatability of 4.86%–9.33%, and excellent reproducibility of 5.62%–9.85% were achieved. Finally, as expected, as the most sensitive SMPE technique for detecting PBDEs, to the best of our knowledge, the developed SPME procedure in combination with gas chromatography–negative chemical ion–mass spectrometry analysis was proven to be ultrasensitive, dependable, and practical in analyzing PBDE species in real water. These exceptional results signify that the proposed method offers a fresh prospect to extend the potential applications of COFs to pick up pollutants at ultra-low levels from environmental samples.

Development of efficient and sensitive adsorbent for capturing phenoxy carboxylic acids (PCAs) from environmental and food samples is necessary because PCAs could threaten human health. Designing nanoparticle with multiple functional groups is beneficial to achieve the strong adsorption interaction and the specific recognition for target compound. In this paper, TpTG

Developing and establishing an efficient pre-treatment approach for the precise extraction of nitrated-polycyclic aromatic hydrocarbons (N-PAHs) from real-life samples is critical for ensuring their safety. In this study, a novel crystalline magnetic covalent organic framework with a grapevine structure not a single core–shell, Fe3O4@TAPT-DMTA-COF, was fabricated via chemical bonding. Unchanging the reticulated structure and high crystallinity of TAPT-DMTA-COF, the combination made this material possess not only simple operation via magnetic decantation but also remarkable chemical stability. Fe3O4@TAPT-DMTA-COF had a large surface area (1578.45 m2/g), and rich electronegative triazine-groups, which makes it become a superior magnetic enrichment material for trace N-PAHs. For N-PAHs analysis, low limits of detection (LODs) (1.43–17.24 ng/L), excellent relative standard deviations (RSDs ≤ 11.52%), and wide linearity (10–5000 ng/L) were obtained. Real-life applications based on this composite have been successfully explored by capturing the N-PAHs emitted from food and environmental samples.

A novel magnetic ionic covalent organic framework (Fe3O4@EB-iCOFs) was designed and synthesized. It was then characterized by X-ray diffraction, N2 adsorption–desorption analysis, and magnetic measurements, among others. The material shows the advantages of ionic property, large surface area, and magnetic responsiveness. It has potential of magnetic solid-phase extraction (MSPE) of perfluorinated compounds (PFCs). A method for the determination of PFCs based on MSPE-HPLC-MS/MS was established. The method has excellent linearity (r ≥ 0.995) in the working range 1-1000 ng L-1 , good repeatability (1.4–5.8%, n = 6), low limits of detection in the range 0.1–0.8 ng L−1 and satisfactory recoveries (between 73.9 and 108.3%).

The novel amino-functionalized magnetic covalent organic framework nanocomposites (Fe3O4@[NH2]-COFs) were fabricated at room temperature, which were explored as a magnetic adsorbent for magnetic solid-phase extraction (MSPE). On the basis of the hydrophobic surfaces of magnetic nanocomposites and introduction of primary amines into the COFs shell, Fe3O4@[NH2]-COFs displayed excellent enrichment capacity in “catching” ultratrace perfluoroalkyl acids (PFAAs) from water samples because of the synergistic combination of hydrophobic and electrostatic interactions between PFAAs and Fe3O4@[NH2]-COFs. Under the optimized pretreatment and instrumental parameters, the proposed pretreatment approach, which hybridized MSPE using Fe3O4@[NH2]-COFs and HPLC-MS/MS, displayed favorable linearity (10–10,000 ng L−1) with R2 (0.9990–0.9999), low limits of detection (0.05–0.38 ng L−1), and excellent repeatability (3.7–9.2%). Moreover, the established approach was successfully utilized to determine PFAAs in real water samples with spiked recoveries ranging from 72.1% to 115.4%. Results indicated that Fe3O4@[NH2]-COFs would be a potential alternative for MSPE of PFAAs at ultra-low levels.

Water quality was highly affected by common pollutants. Metals, pesticides and small molecules are ubiquitous pollutants. Advancement in engineering technology (computer-based monitoring systems) increased the efficiency of quantifying toxicity of different chemicals in an organism. The cardiovascular system reflects internal and external stress of an organism, and electrocardiogram (ECG) data reliably measure external stress. As ECG data can accurately reflect the physiological conditions of organisms, and zebrafish (Danio rerio) are considered to be good models for cardiovascular research, it is hypothesized that ECG parameters of zebrafish could indicate the toxicity of water-borne chemicals. To achieve this, we treated zebrafish with different concentrations of target chemicals (CuSO4, C10H19O6PS2 and NH4Cl) for 48 h and ECG data were measured. P-wave, R-wave, T-wave, PR-interval, QRS-complex and QT-interval data were the focus of this study. The results of self-organizing maps and Pearson correlation analysis indicate that the QRS-complex can be used as an indicator for CuSO4 stress. The QT-interval could be used to assess the C10H19O6PS2 stress. The QT-interval and P-wave can be used to evaluate the NH4Cl stress. Responses of zebrafish ECG parameters were identical with other vertebrate model, and were specific to toxicant types. It is proved that zebrafish heart ECG index could be used as a potential indicator in early detection of environmental stress.

The magnetic layered double hydroxide-based materials (MLDHs) with the metal composition of Mg(II)Al(III) were synthesized by different conditions as the adsorbent for removal of a phytohormone, indole-3-butyric acid (IBA). The morphological characteristics of MLDHs were studied through various characterization methods such as XRD, SEM, TEM, FTIR, BET, Zeta-potential and VSM. The adsorption results showed that the adsorption capacity of MLDH-1 synthesized by co-precipitation method with ammonia as the base source was the best (maximum 522.6 mg/g). The extent of adsorption in the pH range of 3.0–9.0 was observed to be no noticeable change. From the economical point of view, 1.0 g/L MLDH-1 composites were selected as optimum parameter. For a given adsorbent concentration (Cs), its kinetics and adsorption isotherm followed the pseudo-second-order and Liu isotherm model, respectively. The adsorbed sample can be easily magnetically separated and regenerated with NaNO3. The adsorption process was spontaneous and exothermic, including two path stages: surface adsorption of lamellar and interlayer anion exchange. The research makes a contribution to evaluating the ability of MLDHs in IBA removal and helping the public to understand the mechanism of adsorption process.

Novel core shell structured magnetic covalent organic frameworks were synthesized at room temperature and first applied in water samples for the enrichment of trace polybrominated diphenyl ethers (PBDEs) through magnetic solid-phase extraction. The prepared materials were characterized through transmission electron microscopy, Fourier transform infrared spectroscopy, X-ray diffraction, vibrating sample magnetometer and X-ray photoelectron spectroscopy. During adsorption, the parameters affecting extraction and desorption efficiency were further optimized. Combined gas chromatography and mass spectrometry (GC/MS) revealed that high enrichment factors (275–292), low limits of detection (0.12–0.38 ng·L−1), wide linear ranges (0.5–1000 ng·L−1), and good reproducibility (intra-day 1.40%–4.31% and inter-day 5.14%–9.12%) were obtained under optimal conditions. The method successfully detected PBDEs in different water samples.

Food and environmental safety issues attributable to the polybrominated diphenyl ethers (PBDEs) are gaining increasing attention, and these urge us to establish a high-performance sample-handling technique. In this study, an outstanding adsorption performance with short adsorption time (10 min) was achieved for PBDEs using a novel synthesized dispersive solid-phase extraction adsorbent, a reticulated covalent organic framework with N/O functional groups (i.e., imine linkage, triazine, and methoxy) (TAPT-DMTA-COF). By conducting sufficient experimentation and theoretical simulation on adsorption mechanism, the halogen bond between electronegative N/O atoms of TAPT-DMTA-COF and the electropositive Br atoms of PBDEs were observed to play a more pivotal role than π-π, C-H…π interactions, and hydrophobic effects. Furthermore, the positive linear relation between calculated adsorption energy and Br content directly clarified that enrichment behavior of PBDEs can be attributed to halogen bonding. These data implied that integrated nanostructure (i.e., N/O functional groups and reticulated architecture) effectively enhanced adsorption capacity. In case of PBDE analysis, this approach achieved excellent results with low limits of detection (0.03-0.13 ng L-1). Finally, the promising potential applications of aforementioned method were verified by spiking water, fish, and milk samples with PBDEs; good PBDEs recoveries were obtained.

In this study, a novel porous composite (Fe3O4@TAPB-COF@ZIF-8) consisting of metal–organic and covalent organic frameworks was developed and applied to the magnetic solid-phase extraction (MSPE) of bisphenols. The extraction parameters such as the extraction time, solution pH, amounts of adsorbent, and ionic strength were investigated to obtain the best extraction conditions. By optimizing the MSPE, a convenient and sensitive analytical method was established in combination with high-performance liquid chromatography. The method achieved low detection limits (0.04–0.05 ng mL−1), wide linear range (0.25–1000 ng mL−1), good repeatability (1.20–4.30%), good reproducibility (1.34–4.03%), and satisfactory recoveries of four functional beverages (66.2–116.6%).

Efficient extraction of polar sulfonamides antibiotics from aqueous samples and food is very challenging, because they are hydrophilic, their concentration is very low, and the matrix is complex. Covalent organic frameworks (COFs), a novel porous organic material, have attracted great attention. In this work, the spherical triphenylbenzene-dimethoxyterephthaldehyde-COFs (TPB-DMTP-COFs) were synthesized by a simple room temperature method, and due to their attractive properties, such as high outstanding acid-base stability, large specific surface area, low skeletal density, inherent porosity and high crystallinity, so TPB-DMTP-COFs as ideal solid phase extraction adsorbents showed excellent adsorption performance for trace polar sulfonamides in food and water. TPB-DMTP-COFs were characterized by scanning electron microscopy, Fourier-transform infrared spectroscopy, powder X-ray diffraction, and so on. The important parameters were optimized to improve the extraction efficiency of TPB-DMTP-COFs toward sulfonamides. Analysis of sulfonamides was performed by liquid chromatography-tandem mass spectrometry. The developed method based on TPB-DMTP-COFs material achieved low limits of detection (0.5-1.0 ng L-1), wide linearity (5-1000 ng L-1), and good repeatability (2.5%-8.7%). The possible extraction mechanism was also discussed. Finally, the method was successfully applied to the enrichment and detection of sulfonamides in environmental water samples and food samples. The present study indicated that TPB-DMTP-COFs had splendid prospects in highly sensitive analysis of other pollutants in complex matrix.

Superstructures have attracted attention because of their potential applications in chemistry and materials science. In this work, we report the preparation of a porous 3D superstructure of nitrogen-doped carbon decorated with ultrafine cobalt nanodots (Co@NCSS) derived from the self-assembly of polyimide nanoparticles. Utilizing modified ultra-small cobalt nanodots as main catalytically active sites, and the excellent quality and electron transport efficiency generated by this 3D porous superstructure, Co@NCSS exhibited excellent catalytic performance as a peroxymonosulfate (PMS) activator towards the degradation of several sulfonamides. Based on radical scavenging tests and electron paramagnetic resonance (EPR), singlet oxygen (1O2) was the dominant oxidative species. Furthermore, through the identification of degradation intermediates by HPLC-MS and DFT calculation, the pathway of sulfamethoxazole (SMX) degradation by Co@NCSS/PMS was analyzed. The possible catalytic mechanism of Co@NCSS/PMS for SMX degradation is also proposed in this paper. Co@NCSS has the potential to be an ideal material for removing antibiotics from wastewater.

This study demonstrates for the first time the enrichment potential of covalent triazine-based frameworks/iron oxide for the magnetic solid-phase extraction of seven typical polar phenolic pollutants. Important parameters, such as the eluant and its volume, adsorbent amounts, sample pH, extraction time, and ionic strength, were optimized in detail. Under the optimal conditions, low limits of detection (0.09-0.53 ng/mL), wide linear range (25-2000 ng/mL), good repeatability (1.2-8.3%) and reproducibility (1.5-9.9%) were achieved. The developed method was successfully applied to analyze the target phenols at trace levels in environmental water samples.

The high performance separation and pre-concentration of polar phenols from aqueous matrices is difficult because of the strong interactions between phenols and water molecules. Conjugated microporous polymers (CMPs) are a kind of novel porous organic materials. Polyphenylene core-conjugated microporous polymers (PPc-CMPs) were used as a novel coating material in the solid-phase microextraction of polar phenols in water samples for the first time. The novel PPc-CMPs fibers exhibited good thermal stability (>450 °C), high enrichment factors (519–2372), low limits of detection (0.02–0.05 ng L−1), wide linearity (0.1–1000 ng L−1), and good repeatability (2.5%–8.1%) for polar phenols. The new coating was successfully used in the analysis of phenols in real environmental water samples. PPc-CMPs as a polar solid-phase microextraction coating material was excellent for the rapid and sensitive analysis of phenols at trace levels in the environment.

This work demonstrates the extraction potential of carboxylated carbon nanospheres (CNSs-COOH) for solid-phase extraction of perfluoroalkyl acids (PFAAs) for the first time. Six PFAAs, including perfluorohexanesulfonate (PFHxS), perfluoroheptanoic acid (PFHpA), perfluorooctanoic acid (PFOA), perfluorooctanoic sulfonic (PFOS), perfluorononanoic acid (PFNA) and perfluorodecanoic acid (PFDA), were quantitatively adsorbed on a CNSs-COOH-packed cartridge; then, the PFAAs retained on the adsorbent were quantitatively eluted with an optimized volume of acetone (pH = 10). Finally, the desorbed PFAAs were determined by liquid chromatography-tandem mass spectrometry. Important relevant factors, such as the eluant and its volume, sample pH, amount of CNSs-COOH, sample flow rate and sample volume were optimized in detail. Under the optimized conditions, low limits of detection (0.01-1.2ngL-1), wide linear range (0.50-200ngL-1) and good repeatability (2.4-5.1%) and good reproducibility (3.7-8.8%) were obtained. The proposed method was applied to analyze the six PFAAs in real environmental water samples, and satisfactory results were achieved. All of these results showed that CNSs-COOH will be a good choice for the pre-concentration and analysis of target PFAAs at trace levels in environmental water samples in the future.

Covalent organic frameworks (COFs), which are a new type of carbonaceous polymeric material, have attracted great interest because of their large surface area and high chemical and thermal stability. However, to the best of our knowledge, no work has reported the use of magnetic COFs as adsorbents for magnetic solid-phase extraction (MSPE) to enrich and determine environmental pollutants. This work aims to investigate the feasibility of using covalent triazine-based framework (CTF)/Fe2O3 composites as MSPE adsorbents to enrich and analyze perfluorinated compounds (PFCs) at trace levels in water samples. Under the optimal conditions, the method developed exhibited low limits of detection (0.62-1.39 ng·L-1), a wide linear range (5-4000 ng L-1), good repeatability (1.12-9.71%), and good reproducibility (2.45-7.74%). The new method was successfully used to determine PFCs in actual environmental water samples. MSPE based on CTF/Fe2O3 composites exhibits potential for analysis of PFCs at trace levels in environmental water samples. Graphical abstract Magnetic covalent triazine-based frameworks (CTFs) were used as magnetic solid-phase extraction adsorbents for the sensitive determination of perfluorinated compounds in environmental water samples. PFBA perfluorobutyric acid, PFBS perfluorobutane sulfonate, PFDA perfluorodecanoic acid, PFDoA perfluorododecanoic acid, PFHpA perfluoroheptanoic acid, PFHxA perfluorohexanoic acid, PFHxS perfluorohexane sulfonate, PFNA perfluorononanoic acid, PFOA perfluorooctanoic acid, PFPeA perfluoropentanoic acid, PFUdA Perfluoroundecanoic acid.

There is an increase in demand to develop simple, convenient, and low-cost approaches for rapid and label-free detection of antibiotics. Herein, we propose a new principle for the detection of kanamycin using the surface-anchored liquid crystal (LC) droplets. The optical images of the LC droplets uniformly change from four-clover, uniformly dark, and dark cross appearance gradually with the increase of surfactant concentration. The detection of kanamycin is fulfilled with the aid of a cationic surfactant cetyltrimethylammonium bromide (CTAB) and a kanamycin aptamer. The LC droplets show uniformly dark appearance and four-clover appearance in the presence of the aqueous solutions of CTAB and CTAB/aptamer complex, respectively. However, the specific binding of kanamycin to its aptamer can release the CTAB, which induces the uniformly dark appearance of the LC droplets. A portable device is built to measure the optical luminance of the LC droplets. This system can detect kanamycin with a concentration below 0.1 ng/mL (~0.17 nM) and also allows the detection of kanamycin in real samples such as milk and honey. Therefore, it is very promising in the development of new types of LC-based sensors by the surface-anchored LC droplets assisted with a portable optical device.

Gold nanoparticles (AuNPs) were in-situ deposited onto the ordered mesoporous carbon (OMC) to function as a novel SPME coating. The specific area, pore volumes and average pore diameter for OMC and AuNP/OMC were calculated to be 411 and 281 m2 g−1, 0.93 and 0.69 cm3 g−1, 7.1 and 6.8 nm, respectively. The results indicate that the introduction of AuNPs greatly enhances the extraction of anilines, probably due to the strong interaction between gold and amino groups. The composite material was coated onto a fiber which then gave enrichment factors in the range from 1143 to 3420 for anilines, 45 to 845 for alcohols and 86 to 545 for phenols, indicating its extraction selectivity towards aniline. Following desorption, four anilines were quantified by gas chromatography with flame ionization detection. The method has low limits of detection (0.072-0.18 μg L−1) and a good precision (1.9-3.8%). It was successfully applied to the analysis of anilines in river and drinking samples. Recoveries range from 83.9% to 107.7% and 94.0 to 113.1%, respectively.