Imine-linked covalent organic frameworks coated stir bar sorptive extraction of non-steroidal anti-inflammatory drugs from environmental water followed by high performance liquid chromatography-ultraviolet detection

A PEDOT enhanced covalent organic framework (COF) fluorescent probe for in vivo detection and imaging of Fe3

Simple and accurate in vivo monitoring of Fe3+ is essential for gaining a better understanding of its role in physiological and pathological processes. A novel fluorescent probe was synthesized via in situ solid-state polymerization of 3,4-ethylenedioxythiophene (PEDOT) in the pore channels of a covalent organic framework (COF). The PEDOT@COF fluorescent probe exhibited an absolute quantum yield (QY) 3 times higher than COF. In the presence of Fe3+ the PEDOT@COF 475 nm fluorescence emission, 365 nm excitation, is quenched within 180 s. Fluorescence quenching is linear with Fe3+ in the concentration range of 0-960 μM, with a detection limit of 0.82 μM. The fluorescence quenching mechanism was attributed to inner filter effect (IEF), photoinduced electron transfer (PET) and static quenching (SQE) between PEDOT@COF and Fe3+. A paper strip-based detector was designed to facilitate practical applicability, and the PEDOT@COF probe successfully applied to fluorescence imaging of Fe3+ levels in vivo. This work details a tool of great promise for enabling detailed investigations into the role of Fe3+ in physiological and pathological diseases.

3D printed stir bar sorptive extraction coupled with high performance liquid chromatography for trace estrogens analysis in environmental water samples

BACKGROUND

Any imaginary shape with good preparation reproducibility can be made by 3D printing technology, and it has been applied in various fields. Comparatively, its applications in sample pre-treatment are relatively less, most of which involves making extraction sorbents and producing non-functionalized devices for support assistance. 3D printing has not been applied to fabricate stir bars in stir bar sorptive extraction, mainly due to the lacking of suitable printing feedstocks. This work aimed to fabricate stir bars by 3D printing, reducing the manufacturing cost and steps and improving preparation reproducibility. (90) RESULTS: By using fused deposition modeling technique and porous filament printing feedstock, stir bars were fabricated without any modifications. Adsorption performance of 3D printed stir bars were investigated for substances with different structures and polarities. Five estrogens with adsorption efficiencies of over 80 % were selected as the representatives. The 3D printed stir bars exhibited good preparation reproducibility (2.9-4.4 %) and higher extraction recoveries (73-81 %) for five estrogens than commercial polydimethylsiloxane coated stir bars (13-69 %) in a shorter time (90 vs 120 min). They showed long lifespan (160 times) with good mechanical properties and merited reduced manufacturing cost (0.064 $ per bar) and manual operation. A method of stir bar sorptive extraction coupled with high performance liquid chromatography was proposed for trace analysis of estrogens in environmental water. Under the optimized conditions, the linear ranges for estrogens were 0.5-200 μg/L with LODs of 0.13-0.17 μg/L. (136) SIGNIFICANCE: The feasibility of fused deposition modeling in stir bar fabrication was demonstrated, along with the potential of porous filament printing feedstock as the sorbent for substances with medium polarity. 3D printed stir bars were featured with excellent preparation reproducibility, long lifespan, and good mechanical properties. The stir bar fabrication method can be used for mass production with minimal differences in products performance. (62).

Advanced porous organic materials for sample preparation in pharmaceutical analysis

The development of novel sample preparation media plays a crucial role in pharmaceutical analysis. To facilitate the extraction and enrichment of pharmaceutical molecules in complex samples, various functionalized materials have been developed and prepared as adsorbents. Recently, some functionalized porous organic materials have become adsorbents for pharmaceutical analysis due to their unique properties of adsorption and recognition. These advanced porous organic materials, combined with consequent analytical techniques, have been successfully used for pharmaceutical analysis in complex samples such as environmental and biological samples. This review encapsulates the progress of advanced porous materials for pharmaceutical analysis including pesticides, antibiotics, chiral drugs, and other compounds in the past decade. In addition, we also address the limitations and future trends of these porous organic materials in pharmaceutical analysis.

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.

Fluorine-Functionalized Covalent-Organic-Framework-Coated Stir Bar for the Extraction of Benzoylurea Insecticides in Pear Juice and Beverage Followed by High-Performance Liquid Chromatography-Ultraviolet Detection

A fluorinated covalent organic framework (COF), named F-COF, was fabricated via simple room-temperature synthesis. With the characteristics of rich fluorine atoms, hydrophobicity, and large conjugated structure, F-COF was evaluated for the extraction of five benzoylurea insecticides (BUs) containing fluorine atoms, benzene ring, and urea bridge. Specifically, F-COF-coated stir bars were prepared by physical adhesion and exhibited higher extraction recovery (73-93 versus 40-85%) toward BUs than commercial stir bars in a shorter extraction time (50 min versus 24 h). The adsorption behavior of BUs on F-COF was explored, and it was assumed that the halogen bond (O-F), hydrophobic interaction, electrostatic interaction, and π-π stacking contributed to the adsorption. On the basis of it, a method combining stir bar sorptive extraction with liquid chromatography-ultraviolet detector was developed for trace analysis of five BUs. Under the optimal conditions, the limits of detection for BUs were found to be 0.301-0.672 μg/L, with the linear range of 1.0/2.0-500 μg/L and relative standard deviations of <8.0% (c = 5 μg/L and n = 7). The accuracy of the proposed method was validated by the recovery test, and the recoveries of target BUs in spiked pear juice and pear beverage were 82.0-113 and 84.0-112%, respectively.

Recent Advances in the Application of Covalent Organic Frameworks in Extraction: A Review

Covalent organic frameworks (COFs) are a class of emerging materials that are synthesized based on the covalent bonds between different building blocks. COFs possess unique attributes in terms of high porosity, tunable structure, ordered channels, easy modification, large surface area, and great physical and chemical stability. Due to these features, COFs have been extensively applied as adsorbents in various extraction modes. Enhanced extraction performance could be reached with modified COFs, where COFs are presented as composites with other materials including nanomaterials, carbon and its derivatives, silica, metal-organic frameworks, molecularly imprinted polymers, etc. This review article describes the recent advances, developments, and applications of COF-based materials being utilized as adsorbents in the extraction methods. The COFs, their properties, their synthesis approaches as well as their composite structures are reviewed. Most importantly, suggested mechanisms for the extraction of analyte(s) by COF-based materials are also discussed. Finally, the current challenges and future prospects of COF-based materials in extraction methods are summarized and considered in order to provide more insights into this field.

Accelerating the Fe(III)/Fe(II) cycle via enhanced electronic effect in NH2-MIL-88B(Fe)/TPB-DMTP-COF composite for boosting photo-Fenton degradation of sulfamerazine

In the photo-Fenton reactions, fast recombination of photoinduced electrons and holes in Fe-based metal-organic frameworks (Fe-MOFs) slows Fe(III)/Fe(II) cycle, which remains big challenge that significantly retards the overall process. Herein, NH₂-MIL-88B(Fe) (NM88) was modified with 3,5-diaminobenzoic acid (DB) and TPB-DMTP-COF (COF-OMe) to in situ construct NM88(DB)_0.85/COF-OMe composite that could strongly harvest the visible light for photo-Fenton degradation of sulfamerazine (SMR). With the addition of DB, electron-donating effect of NM88 was strengthened, which then promoted amino groups to react with aldehyde groups (Schiff-base), and thus highly facilitated the interfacial contact between NM88 and COF-OMe. Such modifications increased the degradation rate constants for NM88(DB)_0.85/COF-OMe to 15.1 and 17.3 times that of NM88 and COF-OMe respectively with good reusability. Moreover, the catalyst exhibited 32-170 times higher degradation kinetics in comparison to other reported catalysts. Results showed that due to the Schiff-base reaction between NM88(DB) and COF-OMe, electron density on Fe(III) was decreased; and the photogenerated electrons of COF-OMe moved to NM88(DB) to reduce Fe(III), thus resulting in the generation of highly active Fe(II) and ·OH species. Furthermore, the main reactive species were determined to be ·OH and ·O₂^- by trapping experiments, and a possible mechanism of the degradation system followed Z-scheme charge transfer.