Metal organic framework derived Zn/N co-doped hydrophilic porous carbon for efficient solid phase microextraction of polar phenols.

MOF-derived zink and nitrogen co-doped porous carbon (ZNPC) was synthesized through the pyrolysis of MOF-5-NH2 and used as a solid-phase microextraction (SPME) coating material. Coupled with gas chromatography-mass spectrometry (GC-MS), headspace SPME (HS-SPME) based on ZNPC was adopted for the determination of phenols in food samples. The co-existence of N and Zn in ZNPC endows the derived carbon superior hydrophilicity, which is highly beneficial for phenols capture. After optimizing the conditions of extraction and desorption, a sensitive analytical method was established with low limits of detections (LODs, 0.73-2.3 ng g-1) and wide linear ranges (5-5000 ng g-1). Both the intra-fiber repeatability (RSDs from 2.8-7.3%) and inter-fiber reproducibility (RSDs from 9.7-11.7%) were satisfactory. The established method was applied to phenol determination in beef jerky and duck neck with satisfactory recoveries of 81.2-120.4% and RSDs of 2.8-9.9%, which met well with the requirement of practical application.

Adsorptive removal of pharmaceuticals from water using metal-organic frameworks: A review.

Pharmaceutical pollution has emerged as a highly concerned issue due to its adverse effects. Elevated concentrations of pharmaceuticals in water should be regulated to satisfy the requirement for the provision of clean water. Metal-organic frameworks (MOFs) with high specific surface area, controllable porous structure, and facile modification can serve as promising adsorbents for the removal of pharmaceutical contaminants from water. In this review, a selected collection illustrating the reliable strategies and concepts to prepare the MOFs-based materials with superior water stability is described. In addition, recent progress on the adsorptive removal of pharmaceutical pollutant using burgeoning and functional MOFs is also summarized in terms of maximum capacity, equilibrium time, and regenerate ability. Meanwhile, to understand the adsorption mechanism, related interactions including coordination with unsaturated site, pore-filling effect, hydrogen bonding, electrostatic, and π-π stacking are further discussed. Finally, critical perspectives/assessment of future research emphasising on fabricating desirable MOFs and establishing structure-property relationships to facilitate capture performance are identified.

An amino-functionalized ordered mesoporous polymer as a fiber coating for solid phase microextraction of phenols prior to GC-MS analysis.

An amino-functionalized ordered mesoporous polymer (OMP-NH2) was synthesized and applied as a fiber coating for solid phase microextraction of polar phenols from environmental samples. The fiber coating was prepared by loading the OMP-NH2 powder onto a stainless steel wire through silicone gel. Combined with GC-MS, the fibers were employed to quantify trace of phenols in water through headspace-SPME. The characterization showed the OMP-NH2 to have a large specific surface area (420 m2 g-1) and good thermal stability (>400 °C). Due to its mesoporous structure and favorable interactions via hydrogen bonding and π stacking interactions with phenols, the sorbent represents a promising candidate for the separation and enrichment of polar phenols. Extraction conditions, such as temperature, extraction time, salt concentration, pH value and desorption time, were fully optimized. Under the optimized conditions, the coating exhibits an enrichment effect that is ~2-10 times better than that of a commercial polyacrylate coating. Figures of merit include (a) low limits of detection (0.05-0.16 ng L-1), (b) wide linear ranges (0.2-10,000 ng L-1), and (c) high enrichment factors (510-2272). The relative standard deviations for one fiber and fiber-to-fiber were in the range of 4.0-6.1% and 4.6-7.4%, respectively. The method was applied to the determination of phenols in water samples and gave satisfactory recoveries between 85.4 and 112.2%. Graphical abstract An amino-functionalized ordered mesoporous polymer (OMP-NH2) was synthesized by a solventless method and applied as headspace solid phase microextraction (HS-SPME) fiber coating for the extraction of polar phenols from the environmental samples.

Rapid Identification of Unknown Organic Iodine in Small-Volume Complex Biological Samples Based on Nanospray Mass Spectrometry Coupled with in-Tube Solid Phase Microextraction.

A new method for rapid screening of unknown organic iodine (OI) in small-volume complex biological samples was developed using in-tube solid phase microextraction (SPME) nanospray mass spectrometry (MS). The method proposed a new identification scheme for OI based on nanospray high-resolution mass spectrometry (HR-MS). The mass ranges of OI ions were confirmed using the t-MS2 scan mode first; then, the possible precursor ions of OI were selected and identified orderly in full MS/ddMS2 and t-MS2 scan modes. Besides, in-tube SPME was used for the pretreatment of small-volume biological samples, and it was the first time in-tube SPME combined with nanospray MS for OI identification. The whole analysis procedure took only 8 min and consumed 50 µL per sample. Using the new method, six kinds of OI added to urine and an unknown OI C12H23O11I in human milk were successfully identified. Moreover, the proposed identification scheme is also suitable for other ambient mass spectrometry (AMS) to determine unknown compounds with characteristic fragment ions.

Determination of Polycyclic Aromatic Hydrocarbons in Sediment by Pressure-Balanced Cold Fiber Solid Phase Microextraction.

An improved performance of the cold fiber solid phase microextraction (CF-SPME) technique was accomplished with the use of the pressure-balanced procedure. In order to obtain a pressure-balanced state during extraction at 200 °C, 7 mL of air volume was withdrawn from 10 mL commercial vials, while 15 mL was withdrawn from vials where 5 µL of diethylamine was added as a modifier/displacer. The benefits of the balanced system were demonstrated for determination of polycyclic aromatic hydrocarbons (PAHs) from solid matrixes, including sand and certified sediment samples. Results showed the pressure-balanced procedure enhanced the extraction efficiency of the method, especially for high volatility compounds, as the leakage of analytes was mitigated under sample temperature conditions of 200 °C. Analytical precision was also improved, with relative standard deviations (RSDs) ranging from 4% to 8% for all analytes under study. For the determination of PAHs in certified sediment samples, pressure-balanced CF-SPME yielded more accurate results in comparison to nonpressure-balanced CF-SPME. The proposed methodology provided the additional benefit of improved recoveries at lower pressures.

In situ Identification of Labile Precursor Compounds and their Short-lived Intermediates in Plants using in vivo Nanospray High-resolution Mass Spectrometry.

INTRODUCTION: Many secondary metabolites in plants are labile compounds which under environmental stress, are difficult to detect and track due to the lack of rapid in situ identification techniques, making plant metabolomics research difficult. Therefore, developing a reliable analytical method for rapid in situ identification of labile compounds and their short-lived intermediates in plants is of great importance. OBJECTIVE: To develop under atmospheric pressure, a rapid in situ method for effective identification of labile compounds and their short-lived intermediates in fresh plants. METHODOLOGY: An in vivo nanospray high-resolution mass spectrometry (HR-MS) method was used for rapid capture of labile compounds and their short-lived intermediates in plants. A quartz capillary was partially inserted into fresh plant tissues, and the liquid flowed out through the capillary tube owing to the capillary effect. A high direct current (d.c.) voltage was applied to the plant to generate a spray of charged droplets from the tip of the capillary carrying bioactive molecules toward the inlet of mass spectrometer for full-scan and MS/MS analysis. RESULTS: Many labile compounds and short-lived intermediates were identified via this method: including glucosinolates and their short-lived intermediates (existing for only 10 s) in Raphanus sativus roots, alliin and its conversion intermediate (existing for 20 s) in Allium sativum and labile precursor compound chlorogenic acid in Malus pumila Mill. CONCLUSION: The method is an effective approach for in situ identification of internal labile compounds and their short-lived intermediates in fresh plants and it can be used as an auxiliary tool to explore the degradation mechanisms of new labile plant compounds. Copyright © 2016 John Wiley & Sons, Ltd.

Cloning and expression analyses of the anthocyanin biosynthetic genes in mulberry plants.

Anthocyanins are natural food colorants produced by plants that play important roles in their growth and development. Mulberry fruits are rich in anthocyanins, which are the most important active components of mulberry and have many potentially beneficial effects on human health. The study of anthocyanin biosynthesis will bring benefits for quality improvement and industrial exploration of mulberry fruits. In the present study, nine putative genes involved in anthocyanin biosynthesis in mulberry plants were identified and cloned. Sequence analysis revealed that the mulberry anthocyanin biosynthetic genes were conserved and had counterparts in other plants. Spatial transcriptional analysis showed detectable expression of eight of these genes in different tissues. The results of expression and UPLC analyses in two mulberry cultivars with differently colored fruit indicated that anthocyanin concentrations correlated with the expression levels of genes associated with anthocyanin biosynthesis including CHS1, CHI, F3H1, F3'H1, and ANS during the fruit ripening process. The present studies provide insight into anthocyanin biosynthesis in mulberry plants and may facilitate genetic engineering for improvement of the anthocyanin content in mulberry fruit.

Determination of fatty acids in soil samples by gas chromatography with mass spectrometry coupled with headspace solid-phase microextraction using a homemade sol-gel fiber.

Through the use of a homemade sol-gel-derived fiber, a headspace solid-phase microextraction technique coupled to gas chromatography with mass spectrometry was developed for the determination of fatty acids with long, even-numbered carbon chains (C12 -C24 ) in soil samples. The experimental parameters such as reaction time, temperature, and ionic strength that might affect derivatization, extraction, and desorption were investigated. Under the optimized conditions, the linearity of the method ranged from 0.1 to 100 mg/L with a correlation coefficient >0.997. The limit of detection values based on a signal-to-noise ratio of 3:1 were determined with the concentration from 0.39 to 39.4 µg/L. The recoveries of the method for the soil samples were from 91.15 to 108.1%. This developed method using a homemade fiber showed a higher sensitivity than that using a commercial polydimethylsiloxane fiber and was also for the analysis of real soil samples from the Paomaling geological park of China.

Recent progress of covalent organic frameworks as attractive materials for solid-phase microextraction: A review.

Solid-phase microextraction (SPME) is a green, environmentally friendly, and efficient technique for sample pre-treatment. Covalent organic frameworks (COFs), a class of porous materials formed by covalent bonds, have gained prominence owing to their remarkable attributes, including large specific surface area, tunable pore size, and robust thermal/chemical stability. These characteristics have made COFs highly appealing as potential coatings for SPME fiber over the past decades. In this review, various methods used to prepare SPME coatings based on COFs are presented. These methods encompass physical adhesion, sol-gel processes, in situ growth, and chemical cross-linking strategies. In addition, the applications of COF-based SPME coating fibers for the preconcentration of various targets in environmental, food, and biological samples are summarized. Moreover, not only their advantages but also the challenges they pose in practical applications are highlighted. By shedding light on these aspects, this review aims to contribute to the continued development and utilization of COF materials in the field of sample pretreatment.

Urchin-like covalent organic frameworks templated Au@Ag composites for SERS detection of emerging contaminants.

Au@Ag core-shell composites were successfully fabricated on urchin-like covalent organic frameworks (COFs), providing a platform with numerous hot spots for the detection of two categories of emerging contaminants: sulfonamide antibiotics and nanoplastics, using surface-enhanced Raman spectroscopy (SERS). Au seeds (∼10 nm) were generated on the COFs, leveraging the reducing properties of the vinyl and imino groups within the framework. This ensured the growth of dense and uniformly distributed Ag nanoparticles. The COFs exceptionally large surface area (2324 m2 g-1) and high adsorption capacity, significantly contributed to the enrichment and detection of trace pollutants. As a result, using a portable Raman spectrometer, limits of detection of 0.008 µmol L-1 for sulfamethoxazole and 0.029 mg L-1 for polystyrene nanoplastics were achieved.

Deciphering the relationship between the ordered pore structure and solid-phase microextraction behavior of covalent organic frameworks for phenols.

The extraction performance of materials is highly related to their physical structure. However, the precise impact of ordered pore structure in covalent organic frameworks (COFs) on extraction performance are still puzzling. To look insight into this, a series of COFs with varying degrees of ordered pore structures were prepared at room temperature by adjusting reaction time and their extraction efficiencies toward phenolic compounds were investigated. The experimental results revealed that the COF with a short range ordered pore structure exhibited a higher affinity for phenolic compounds along with a larger enrichment factor, while the COF with a long range ordered pore structure demonstrated faster extraction kinetics. The investigation into interaction mechanism revealed that the density of available sites is responsible for these differences. Taking COF-OMe-0.5 h as solid-phase microextraction fiber coating, a highly efficient and sensitive quantitative analysis method for phenolic compounds was established by combining it with gas chromatograph-mass spectrometer. The established method boasts high enrichment factors (7192-29440), wide linear ranges (2.0-10000 ng L-1), and low detection limits (0.24-0.54 ng L-1). This study provides a conceptual guide for constructing desirable COFs with controlled pore structures for specific applications.

Covalent Organic Framework Nanoarchitectonics: Recent Advances for Precious Metal Recovery.

The recovery of precious metals (PMs) from secondary resources has garnered significant attention due to environmental and economic considerations. Covalent organic frameworks (COFs) have emerged as promising adsorbents for this purpose, owing to their tunable pore size, facile functionalization, exceptional chemical stability, and large specific surface area. This review provides an overview of the latest research progress in utilizing COFs to recover PMs. Firstly, the design and synthesis strategies of chemically stable COF-based materials, including pristine COFs, functionalized COFs, and COF-based composites, are delineated. Furthermore, the application of COFs in the recovery of gold, silver, and platinum group elements is delved into, emphasizing their high adsorption capacity and selectivity as well as recycling ability. Additionally, various interaction mechanisms between COFs and PM ions are analyzed. Finally, the current challenges faced by COFs in the field of PM recovery are discussed, and potential directions for future development are proposed, including enhancing the recyclability and reusability of COF materials and realizing the high recovery of PMs from actual acidic wastewater. With the targeted development of COF-based materials, the recovery of PMs can be realized more economically and efficiently in the future.

Porphyrin-based magnetic porous organic polymer for efficient magnetic solid phase extraction of nonsteroidal anti-inflammatory drugs from water.

The ubiquitous occurrence of nonsteroidal anti-inflammatory drugs (NSAIDs) in the environmental water system has drawn significant concerns due to their adverse effects. The accurate monitoring the content of them is of great significance but challenging in terms of the complex matrix and trace concentration. In this work, a porphyrin-based magnetic porous organic polymer composite (PM-POP) was prepared through a solvent-free synthetic method. Owing to the highly porous structure and strong affinities, the as-prepared PM-POP could be utilized as a highly efficient adsorbent for the magnetic solid phase extraction (MSPE) of NSAIDs. Combining with the high-performance liquid chromatography separation with ultraviolet detector (HPLC-UV), a sensitive analytical method was established, which exhibited wide linear ranges (0.1-400 µg/L) and large enrichment factors (EFs) (39.5-82.9 folds) along with good precision (intra-day RSD ≤ 4.9%) and repeatability (inter-day RSD ≤ 8.4%). Ultimately, it was applied to determinate trace NSAIDs in practical water samples successfully, demonstrating its good application prospect in environmental analysis.

Nanoarchitectonics of Hollow Covalent Organic Frameworks: Synthesis and Applications.

Hollow covalent organic frameworks (COFs) have gained significant attention because of their specific properties, including enhanced surface-to-volume ratio, large surface area, hierarchical structure, highly ordered nanostructures, and excellent chemical stability. These intrinsic characteristics endow hollow COFs with fascinating physicochemical properties and make them highly attractive for widespread applications, such as catalysis, energy storage, drug delivery, therapy, sensing, and environmental remediation. This review focuses on the recent developments in the synthesis of hollow COFs and their derivatives. In addition, their practical applications in various fields are summarized. Finally, challenges and future opportunities in terms of their synthetic methodologies and practical applications are discussed. Hollow COFs are expected to play an important role in the future of materials science.

Efficient arsenic coagulation by serpentine-mediated iron hydroxides.

A new method was developed for the coagulation of arsenic with serpentine and Fe(II). Excellent removal efficiency (>99%) and satisfactory stability of the sediments were accomplished for As(V) and As(III). A mechanism study showed that hydroxyls generated by the surface hydrolysis of serpentine mediated active iron hydroxides for arsenic adsorption, while the Fe-As and Mg-As chemical interaction contributed to the arsenic stabilization.

Inhibition of GSDMD-mediated pyroptosis triggered by Trichinella spiralis intervention contributes to the alleviation of DSS-induced ulcerative colitis in mice.

BACKGROUND: Inflammatory bowel disease (IBD), including Crohn's disease (CD) and ulcerative colitis (UC), is increasing worldwide. Although there is currently no completely curative treatment, helminthic therapy shows certain therapeutic potential for UC. Many studies have found that Trichinella spiralis (T.s) has a protective effect on UC, but the specific mechanism is still unclear. METHODS: Balb/c mice drank dextran sulfate sodium (DSS) to induce acute colitis and then were treated with T.s. In vitro experiments, the LPS combination with ATP was used to induce the pyroptosis model, followed by intervention with crude protein from T.s (T.s cp). Additionally, the pyroptosis agonist of NSC or the pyroptosis inhibitor vx-765 was added to intervene to explore the role of pyroptosis in DSS-induced acute colitis. The degree of pyroptosis was evaluated by western blot, qPCR and IHC, etc., in vivo and in vitro. RESULTS: T.s intervention significantly inhibited NLRP3 inflammasome activation and GSDMD-mediated pyroptosis by downregulating the expression of pyroptosis-related signatures in vitro (cellular inflammatory model) and in vivo (DSS-induced UC mice model). Furthermore, blockade of GSDMD-mediated pyroptosis by the caspase-1 inhibitor vx-765 has a similar therapeutic effect on DSS-induced UC mice with T.s intervention, thus indicating that T.s intervention alleviated DSS-induced UC in mice by inhibiting GSDMD-mediated pyroptosis. CONCLUSION: This study showed that T.s could alleviate the pathological severity UC via GSDMD-mediated pyroptosis, and it provides new insight into the mechanistic study and application of helminths in treating colitis.

Fast and efficient extract oseltamivir from aquatic products using magnetic covalent organic frameworks/graphene oxide composite prior to liquid chromatography-tandem mass spectrometry analysis.

In this work, a magnetic covalent organic framework/graphene oxide composite (MCOF/GO) was rapidly synthesized and developed as a promising candidate for the magnetic solid-phase extraction (MSPE). Combined with HPLC-MS, an efficient and rapid analytical method was established for the determination of oseltamivir (OS) in aquatic products. The resultant composite not only exhibited superior extraction efficiency, but also possessed fast mass transfer kinetic, reducing the pretreatment time greatly. Under optimal conditions, the linear range of the proposed method for OS determination was found to be 0.1-10 µg/kg along with a satisfactory correlation coefficient (R2 = 0.997) and a low limit of detection (LOD, 0.035 µg/kg). Furthermore, the established method was utilized to determine OS in Carp, Yellow croaker, and Shrimp, where the recoveries ranged from 87% to 116%. These results demonstrate the splendid application potential of this method to detect antiviral drugs in actual aquatic products.

Early warning model construction and validation for urinary tract infection in patients with neurogenic lower urinary tract dysfunction (NLUTD): a retrospective study.

Background: This study was performed to construct and validate an early risk warning model of urinary tract infection in patients with neurogenic lower urinary tract dysfunction (NLUTD). Methods: Eligible patients with NLUTD admitted to Shenzhen Longcheng hospital from January 2017 to June 2021 were recruited for model construction, internal validation and external validation. The first time point of data collection was within half a month of patients first diagnosed with NLUTD. The second time point was at the 6-month follow-up. The early warning model was constructed by logistic regression. The model prediction effects were validated using the area under the Receiver Operating Characteristic curve, the Boostrap experiment and the calibration plot of the combined data. The model was externally validated using sensitivity, specificity and accuracy. Results: Six predictors were identified in the model, namely patients ≥65 years old (OR = 2.478, 95%CI [1.215- 5.050]), female (OR = 2.552, 95%CI [1.286-5.065]), diabetes (OR = 2.364, 95%CI) [1.182-4.731]), combined with urinary calculi (OR = 2.948, 95%CI [1.387-6.265]), indwelling catheterization (OR = 1.988, 95%CI [1.003 -3.940]) and bladder behavior training intervention time ≥2 weeks (OR = 2.489, 95%CI [1.233-5.022]); and the early warning model formula was Y = 0.907 ×  age+ 0.937 × sex + 0.860 × diabetes +1.081 × combined with urinary calculi+ 0.687 × indwelling catheterization+ 0.912 × bladder behavior training intervention time-2.570. The results show that the area under the ROC curve is 0.832, which is close to that of 1,000 Bootstrap internal validation (0.828). The calibration plot shows that the early warning model has good discrimination ability and consistency. The external validation shows the sensitivity is 62.5%, the specificity is 100%, and the accuracy is 90%. Conclusion: The early warning model for urinary tract infection in patients with NLUTD is suitable for clinical practice, which can provide targeted guidance for the evaluation of urinary tract infection in patients with NLUTD.