Recent progress of selective adsorbents: From preparation to complex sample pretreatment

Development and Application of a Selective Analytical Method for Indole Metabolites in Urine: Dietary Exposure Biomarkers for Broccoli Consumption

The identification of dietary exposure biomarkers is crucial for advancing our understanding of the health benefits of specific foods. Broccoli, a vegetable with well-known anticancer properties, contains active ingredients, such as isothiocyanates with indole side chains. Hence, indole metabolites related to broccoli consumption have the potential to serve as biomarkers of dietary exposure. In this work, we developed a new analytical method for indole metabolites in urine using a poly(deep eutectic solvents)-molecularly imprinted polymer/vinyl-functionalized graphene oxide (PDESs-MIP/VGO) in miniaturized centrifugal pipet-tip solid-phase extraction (CPT-SPE) coupled with liquid chromatography. This method integrates the strengths of PDESs-MIP/VGO, including rich adsorption interactions, high adsorption capacity, and excellent selectivity, with the simplicity and cost-effectiveness of CPT-SPE. The proposed method demonstrated low limits of quantification (1.2-2.5 ng mL-1), high accuracy (91.7-104.8%), and good precision (relative standard deviation ≤4.4%). By applying this method to analyze indole metabolites in urine, our results suggested that indole-3-carbinol and indole-3-acetonitrile have the potential to emerge as reliable dietary exposure biomarkers for broccoli intake. Furthermore, highly selective analytical methods based on molecular imprinting technology are advantageous for precise screening and analysis of dietary exposure biomarkers associated with food consumption.

Hollow multi-shelled MOF derivative adsorbent for efficient magnetic solid-phase extraction of several typical endocrine disrupting compounds from water

Bisphenols and benzophenones are two typical kinds of endocrine-disrupting compounds (EDCs) that have been extensively detected in water environments, posing unanticipated risks to aquatic organisms and humans. It is urgent to develop efficient sample pretreatment methods for precise measurement of such EDCs. In this study, a magnetic and multi-shelled metal-organic framework derivative material has been prepared to extract and enrich trace bisphenols and benzophenones from water. Via a solvothermal reaction induced by sodium citrate followed by a carbonization treatment, a ZIF-67@ZIF-8 derived CoZn-magnetic hierarchical carbon (CoZn-MHC) material has been synthesized as a high-performance magnetic solid-phase extraction (MSPE) adsorbent. This adsorbent exhibited a good specific surface area (213.80 m2⋅g-1) and a saturation magnetization of 63.2 emu·g-1. After the optimization of several parameters (including adsorbent dosage, extraction time, pH, ionic strength, desorption solvent, and solvent volume), an efficient MSPE method for several EDCs (comprising bisphenols and benzophenones) was developed with a good linear range (R2 ≥ 0.990), a high sensitivity range (LODs: 0.793-5.37 ng⋅L-1), and good reusability (RSD ≤4.67 % in five consecutive tests). Furthermore, the material exhibited commendable resistance to matrix interference in natural water samples with the recovery rates of target compounds ranging from 74.8 % to 107 %. We envision that the preparation strategy of this functional metal-organic framework (MOF)-based adsorbent for EDCs may provide insights for relevant research in the future.

One-Pot Preparation of Mixed-Mode Reversed-Phase Anion-Exchange Silica Sorbent and its Application in the Detection of Cyclopiazonic Acid in Feeds and Agricultural Products

A novel co-bonded octyl and pyridine silica (OPS) sorbent was prepared and applied for the solid phase extraction (SPE) of cyclopiazonic acid (CPA, a type of mycotoxin) in feed and agricultural products for the first time. A simple mixed-ligand one-pot reaction strategy was employed for OPS sorbent preparation. Nitrogen adsorption-desorption measurements, elemental analysis (EI), thermal gravimetric analysis (TGA), and Fourier transform infrared spectroscopy (FT-IR) analysis demonstrated the successful immobilization of octyl and quaternary ammonium groups onto the surface of silica gel. The large specific surface area, high-density functional groups, and mixed-mode anion-exchange characteristics of these silica particles made them the ideal material for the efficient extraction of CPA. Additionally, the OPS sorbents displayed excellent batch-to-batch reproducibility, satisfactory reusability, and low cost. The SPE parameters were optimized to explore the ionic and hydrophobic interactions between CPA and the functional groups, and the ultra-high performance liquid chromatography coupled with triple-quadrupole tandem mass spectrometry (UPLC-MS/MS) parameters were optimized to obtain a desirable extraction efficiency and high sensitivity to CPA. Meanwhile, the OPS sorbent presented a satisfactory extraction selectivity and low matrix effect. Under the optimized conditions, our developed CPA detection method was used to determine CPA level in rice, wheat flour, corn flour, peanut, and feed samples, exhibiting a lower detection limit, better linearity, higher sensitivity, and satisfactory extraction recovery rate than previously reported methods. Therefore, our method can be preferentially used as a method for the detection of CPA in agricultural products and feeds.

Rational design of nanozyme with integrated sample pretreatment for colorimetric biosensing

Nanozymes have been widely used in the field of biosensing owing to their high stability, low cost, adjustable catalytic activity, and convenient modification. However, achieving high selectivity and sensitivity simultaneously in nanozyme-based colorimetric sensing remains a major challenge. Nanozymes are nanomaterials with enzyme-simulating activity that are often used as solid-phase adsorbents for sample pretreatment. Our design strategy integrated sample pretreatment function into the nanozyme through separation and enrichment, thereby improving the selectivity and sensitivity of nanozyme-based colorimetric biosensing. As a proof-of-concept, glucose was used as the model analyte in this study. A phenylboric acid-modified magnetic nanozyme (Cu/Fe3O4@BA) was rationally designed and synthesized. Selectivity was enhanced by boronate-affinity specific adsorption and the elimination of interference after magnetic separation. In addition, magnetic solid-phase extraction enrichment was used to improve the sensitivity. A recovery rate of more than 80% was reached when the enrichment factor was 50. The synthesized magnetic Cu/Fe3O4@BA was recyclable at least five times. The proposed method exhibited excellent selectivity and sensitivity, simple operation, and recyclability, providing a novel and practical strategy for designing multifunctional nanozymes for biosensing.

Miniaturized centrifugation accelerated pipette-tip matrix solid-phase dispersion based on poly(deep eutectic solvents) surface imprinted graphene oxide composite adsorbent for rapid extraction of anti-adipogenesis markers from Solidago decurrens Lour

Overweight and obesity are the causes of many diseases and have become global "epidemics". Research on natural active components with anti-adipogenesis effects in plants has aroused the interest of researchers. One of the most critical problems is establishing sample preparation and analytical techniques for quickly and selectively extracting and determining the active anti-adipogenesis components in complex plant matrices for developing new anti-adipogenic drugs. In this study, a new poly(deep eutectic solvents) surface imprinted graphene oxide composite (PDESs-MIP/GO) with high selectivity for phenolic acids was prepared using deep eutectic solvents as monomers and crosslinkers. A miniaturized centrifugation-accelerated pipette-tip matrix solid-phase dispersion method (CPT-MSPD) with PDESs-MIP/GO as adsorbent, coupled with high-performance liquid chromatography, was further developed for the rapid determination of anti-adipogenesis markers in Solidago decurrens Lour. (SDL). The established method was successfully used to determination anti-adipogenesis markers in SDL from different regions, with the advantages of accuracy (recoveries: 94.4 - 115.9 %, RSDs ≤ 9.8 %), speed (CPT-MSPD time: 11 min), selectivity (imprinting factor: ∼2.0), and economy (2 mg of adsorbent and 1 mL of solvents), which is in line with the current advanced principle of "3S+2A" in analytical chemistry.

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.

PDMS-TiO2 composite films combined with LC-MS/MS for determination of phospholipids of urine in non-small cell lung cancer patients with traditional Chinese medicine syndromes

Lung cancer is one of the most common malignant tumors in China. Most patients are already in the mid to advanced stages during the consultation and the survival rate is less than 23 % with a poor prognosis. Therefore, effective dialectical diagnosis of advanced cancer can guide individualized treatment to improve survival. Phospholipids are the building blocks of cell membranes and abnormal phospholipid metabolism is associated with plentiful diseases. Most studies of disease markers use blood as a sample. However, urine covers extensive metabolites that are produced during the body's metabolic processes. Therefore, the study of markers in urine can be used as a complement to improve the diagnosis rate of marker diseases. Moreover, urine is characterized by high water content, high polarity, and high inorganic salt, therefore the detection of phospholipids in urine is challenging. In this study, an original Polydimethylsiloxane (PDMS)-titanium dioxide (TiO₂) composite film for sample pre-treatment coupled with the LC-MS/MS method for the determination of phospholipids in the urine with high selectivity and low matrix effects was prepared and developed. The extraction process was scientifically optimized by the single-factor test. After systematic validation, the established method was successfully applied to the accurate determination of phospholipid substances in the urine of lung cancer patients and healthy subjects. In conclusion, the developed method has great potential for the development of lipid enrichment analysis in urine and can be used as a beneficial tool for cancer diagnosis and Chinese medicine syndrome typing.

Recent applications of organic molecule-based framework porous materials in solid-phase microextraction for pharmaceutical analysis

Sample preparation is an indispensable part of detection of complex samples in pharmaceutical analysis. Solid-phase microextraction (SPME) has obtained a lot of attention due to its advantages of time saving, less solvent and easily automation. A variety of functional materials are used as sorbents in SPME to carry out selective and high extraction. This review centers around the recent applications of organic molecule-based framework porous materials, such as metal organic frameworks (MOFs) and covalent organic frameworks (COFs), as SPME coating materials mainly focus on pharmaceutical analysis in food, environment, and biological samples. Four representative extraction devices are introduced, including on-fiber SPME, in-tube SPME, thin film SPME, stir bar SPME. The application prospect of other organic porous materials as sorbents for pharmaceutical analysis are also discussed, such as hyper crosslinked polymers (HCPs) and conjugated microporous polymers (CMPs). The progresses and discusses are provided to offer references for further research focusing on application and development of organic molecule-based framework porous materials in the field of SPME.

Novel chemically cross-linked self-molding particulate sorbents as solid-phase extraction media

Here, we describe novel, chemically cross-linked, self-molding particulate polymer sorbents that are utilized as a molding-type solid-phase extraction medium (M-SPEM), which exhibits high permeability and rigidness. To fabricate such M-SPEM, first, polyethyleneimine (PEI)-modified reversed-phase (RP)-type particulate sorbents were synthesized, thereafter, they were chemically cross-linked by a polymer having many epoxy groups together with additional PEI. By optimizing the binding conditions of the particulate sorbents, the resultant M-SPEM has almost the same adsorption properties as the corresponding unmolded particulate sorbent for some polar (e.g., uracil and adenine) compounds. The binding technique proposed here is expected to facilitate the fabrication of molding-type sorbents and improve the performance of the SPE procedure.

Generic imprinted fiber array strategy for high-throughput and ultrasensitive simultaneous determination of multiple neonicotinoids

Herein, a new generic fiber array based on molecular imprinting solid-phase microextraction (MIP-SPME) technology, was described to enrich trace multiple neonicotinoids with high flux from the food matrix. To begin with adsorption experiments coupled with theoretical calculations provided universal means for selecting the preferred template molecule clothianidin (CLT). Results demonstrated that the CLT-MIP fiber array exhibited significantly superior enrichment ability of 1189-2356-folds for six neonicotinoids compared with two kinds of commercial fiber arrays. Furthermore, the practicability of the CLT-MIP fiber array was verified by simultaneously determining multiple neonicotinoids in tea and honey samples. The CLT-MIP fiber array showed a limit of detection (LOD) of 0.03-0.58 μg/L for six neonicotinoids. The method also exhibited satisfactory recoveries ranging from 85.4% to 116.8% with RSD (n = 3) less than 8.8%. The imprinted fiber array has the advantages of high-throughput, predominant reproducibility, and accurate quantitation multi-component, and it may open up a new mean to efficiently enrich high-throughput and simultaneously detect multiple compounds from food samples.

Wettability tunable metal organic framework functionalized high internal phase emulsion porous monoliths for fast solid-phase extraction and sensitive analysis of hydrophilic heterocyclic amines

Surface wettability greatly influences the adsorptive, catalytic, and diffuse performances of a porous material. To realize the improved adsorption performance to hydrophilic heterocyclic amines (HAs), polymeric high internal phase emulsions (polyHIPEs) that can be tuned from hydrophobic to hydrophilic is synthesized by facilely regulating the amount of metal organic frameworks (MOFs). The water contact angle of the MOFs and polyHIPEs hybrids (MOFs@polyHIPEs) decreases from 133° to 0° as the amount of amide-modified MOFs increases from 0% to 10%. The hydrophilization of divinybenzene (DVB) based polyHIPEs by MOFs hybridization significantly enhances their adsorption performance and enables them to be suitable for the solid phase extraction (SPE) of hydrophilic HAs. Under the optimized conditions, the MOFs@polyHIPEs achieve adsorption capacities ranging from 42.89 to 86.71 µg/g for HAs through the π-π interaction and hydrogen bonding. The adsorption follows the pseudo-second-order kinetic model, and the nitrogen atoms in/on the imidazole ring are identified as the active adsorption sites for hydrogen bonding. This SPE method, along with HPLC-MS detection, provides detection limits of HAs as low as 0.00020-0.00040 ng/mL. This work offers a feasible strategy in tuning the surface wettability of polyHIPEs without post-modification to achieve high-efficiency enrichment and analysis of HAs.

Room temperature fabrication of magnetic covalent organic frameworks for analyzing sulfonamide residues in animal-derived foods

A magnetic solid phase extraction method based on magnetic covalent organic frameworks (TpBD@Fe₃ O₄ ) combined with high performance liquid chromatography has been developed to detect the sulfonamides including sulfadiazine, sulfamerazine, sulfamethazine and sulfamethoxazole in milk and meat. TpBD@Fe₃ O₄ were synthesized at room temperature under mild reaction conditions with a simple and rapid operation. The TpBD@Fe₃ O₄ exhibited higher extraction efficiency because of the π-π and electrostatic interactions between the benzene ring structure of the TpBD and the SA molecules. The extraction conditions including the dosage of adsorbents, the type and dosage of eluent, the elution time and the pH of the sample solution were fully optimized. The detection results showed good linearity over a wide range (50-5×10⁴ ng/mL) and low detection limits (3.39-5.77 ng/mL) for the SA targets. The practicability of this MSPE-HPLC method was further evaluated by analyzing milk and meat samples, with recoveries of the targets of 71.6%-110.8% in milk and 71.9%-109.7% in pork. The successful detection of SAs residues has demonstrated the TpBD@Fe₃ O₄ excellent practical potential for analyzing pharmaceutical residues in animal-derived foods. This article is protected by copyright. All rights reserved.

Application of a novel nylon needle filter-based solid-phase extraction device to determination of 1-hydroxypyrene in urine

In this work, a simple and miniaturized solid-phase extraction device was constructed by connecting a commercial nylon needle filter to a syringe, which was applied for extracting 1-hydroxypyrene from urine sample via hydrophobic and hydrogen bond interactions. The nylon membrane in the needle filter acted as the solid-phase extraction adsorbent, meanwhile, it filtered the particles in the urine sample. To obtain high extraction efficiency, key parameters influencing extraction recovery were investigated. The entire pretreatment process was accomplished within 5 min under the optimal conditions. By coupling HPLC-UV, a rapid, low-cost, and convenient nylon needle filter-based method was established for the analysis of 1-hydroxypyrene in complex urine matrix. Within the linearity range of 0.2-1000 μg/L, the method exhibited a satisfactory correlation coefficient (R = 0.9999). The limit of detection was 0.06 μg/L, and the recoveries from urine sample spiked with three concentrations (5, 20, and 100 μg/L) ranged from 105.8% to 113.1% with the relative standard deviations less than 6.7% (intra-day, n = 6) and 8.9% (inter-day, n = 4). Finally, the proposed method was successfully applied for detecting 1-hydroxypyrene in urine samples from college students, smokers, gas station workers, and chip factory workers. The detected concentration in actual urine samples ranged from 0.46 to 5.26 μg/L. Taken together, this simple and cost-effective nylon needle filter-based solid-phase extraction device showed an excellent application potential for pretreating hydrophobic analytes from aqueous samples. This article is protected by copyright. All rights reserved.

Constructing porous intramolecular donor–acceptor integrated carbon nitride doped with m-aminophenol for boosting photocatalytic degradation and hydrogen evolution activity

A porous intramolecular D–A integrated carbon nitride with boosted photocatalytic activity was constructed via thermal melting followed by thermal copolymerization of m-aminophenol with urea.

Development of a highly efficient in-tube solid-phase microextraction system coupled with UHPLC-MS/MS for analyzing trace hydroxyl polycyclic aromatic hydrocarbons in biological samples

Hydroxyl polycyclic aromatic hydrocarbons are considered active mutagenic and carcinogenic substances and are found in extremely low levels (ng/g) in biological samples. As a result, their determination in urine and blood samples is challenging, and a sensitive and effective method for the analysis of trace hydroxyl polycyclic aromatic hydrocarbons in complex biological matrices is required. In this work, a novel macroporous in-tube solid-phase microextraction monolith was prepared via a thiol-yne click reaction, and a highly efficient analytical method based on in-tube solid-phase microextraction coupled with UHPLC-MS/MS was developed to determine hydroxyl polycyclic aromatic hydrocarbons with low detection limits of 0.137-11.0 ng/L in complex biological samples. Four hydroxyl polycyclic aromatic hydrocarbons, namely, 2-hydroxyanthraquinone, 1-hydroxypyrene, 1,8-dihydroxyanthraquinone, and 6-hydroxychrysene, were determined in the urine samples of smokers, non-smokers, and whole blood samples of mice. Satisfactory recoveries were achieved in the range of 83.1-113% with relative standard deviations of 3.2-9.7%. It was found that implementation of the macroporous monolith gave a highly efficient approach for enriching trace hydroxyl polycyclic aromatic hydrocarbons in biological samples.

Hypercrosslinked polymer microspheres decorated with anion- and cation-exchange groups for the simultaneous solid-phase extraction of acidic and basic analytes from environmental waters

Mixed-mode ion-exchange sorbents were introduced to improve the selectivity and retention of solid-phase extraction (SPE) sorbents. Mixed-mode ion-exchange sorbents integrate reversed-phase chemistry with ion-exchange groups to promote favourable interactions with ionic species. Nevertheless, a need to extract analytes with acidic and basic properties simultaneously within the same SPE cartridge led to the introduction of novel amphoteric/zwitterionic sorbents, which incorporate cation- and anion-exchange moieties within the same functional group attached to the polymeric network. In the present study, the development, preparation and SPE evaluation of two novel hypercrosslinked zwitterionic polymeric sorbents, functionalised with either strong anion-exchange (SAX) and weak cation-exchange (WCX) or weak anion-exchange (WAX) and strong cation-exchange (SCX) groups (namely HXLPP-SAX/WCX and the HXLPP-WAX/SCX), is presented for the simultaneous retention of acidic and basic compounds. The sorbents were prepared by a precipitation polymerisation route which yielded poly(divinylbenzene-co-vinylbenzylchloride) as a precursor polymer; subsequently, the precursor polymer was hypercrosslinked, to increase the specific surface areas and capacities of the sorbents, and then functionalised to impart the zwitterionic character. The HXLPP-SAX/WCX sorbent was decorated with quaternised sarcosine groups and the HXLPP-WAX/SCX sorbent was decorated with taurine moieties. The SPE parameters were optimised to exploit the ionic interactions between compounds and the functional groups. The optimal conditions involve a washing step to remove the compounds retained by hydrophobic interactions, thus increasing the selectivity. The optimised SPE protocol used the quaternised sarcosine-based sorbent followed by liquid chromatography and tandem mass spectrometry, and was applied to determine compounds with acidic and basic properties from environmental samples, such as river water and effluent wastewater samples, with excellent selectivity and matrix effect values below -30% and apparent recovery results ranging from 52% to 105% for most of the compounds. The analytical method was validated for environmental water samples and used in the analysis of samples in which some of the target compounds were found at ng L^-1 concentration levels.

[Advances in application of molecularly imprinted polymers to the detection of polar pesticide residues]

Polar pesticides can be primarily classified as fungicides, herbicides, and insecticides; their rich variety and low cost have led to their extensive utilization in agriculture. However, the overuse of polar pesticides can lead to environmental contamination, such as water or soil pollution, which can also increase the risk of pesticide exposure among human life directly, or indirectly through contact with animal and plant-derived food. There are considerable differences in the physical and chemical properties of polar pesticides, as well as their trace amounts in complex food and environmental samples, posing immense challenges to their accurate detection. As a kind of artificially prepared selective adsorbent, molecularly imprinted polymers (MIPs) possess specific recognition sites complementary to template molecules in terms of the spatial structure, size, and chemical functional groups. With many advantages such as easy preparation, low cost, as well as good chemical and mechanical stability, MIPs have been widely applied in sample pretreatment and the analysis of polar pesticide residues. MIPs are typically used as adsorption materials in solid phase extraction (SPE) methods, including magnetic solid phase extraction (MSPE), dispersed solid phase extraction (DSPE), and stir bar sorptive extraction (SBSE). To rapidly detect polar pesticide residues with high sensitivity, MIPs are also used in the preparation of fluorescent sensors and electrochemical sensors. Furthermore, MIPs can be employed as the substrate in surface-enhanced Raman spectroscopy and as the substrate for the ion source in mass spectrometry for polar pesticide residue analysis. Thus far, various molecularly imprinted materials have been reported for the efficient separation and analysis of polar pesticide residues in various complex matrices. However, there is no review that summarizes the recent advances in MIPs for the determination of polar pesticides. This review introduces imprinting strategies and polymerization methods for MIPs, and briefly summarizes some new molecular imprinting strategies and preparation technologies. The application of MIPs in recent years (particularly the last five years) to the detection of polar pesticide residues including neonicotinoids, organophosphorus, triazines, azoles, and urea is then systematically summarized. Finally, the future development direction and trends for MIPs are proposed considering existing challenges, with the aim of providing reference to guide future research on MIPs in the field of polar pesticide residue detection.

High throughput determination of free biogenic monoamines and their metabolites in urine using thin-film solid phase microextraction

UPLC-MS/MS methods are the gold standard for routine, high-throughput measurements of biogenic monoamines for the diagnosis of catecholamine-producing tumors. However, this cannot be achieved without employing efficient sample pretreatment methods. Therefore, two pretreatment methods, thin-film solid phase microextraction (TF-SPME) and packed fibers solid phase extraction (PFSPE), were developed and evaluated for the analysis of biogenic monoamines and their metabolites in urine. A hydrophilic-lipophilic balance (HLB) coating was chosen for the thin-film blade format SPME method and compared with a Polycrown ether (PCE) composite nanofiber used as an adsorbent for the PFSPE method. Under optimal conditions, the absolute extraction recovery and relative matrix effect of the newly developed TF-SPME method were determined to be 35.7-74.8% and 0.47-3.63%, respectively. The linearity was 0.25-500 ng mL^-1 for norepinephrine, epinephrine, dopamine, normetanephrine 3-methoxytyramine, serotonin, histamine, and 0.1-500 ng mL^-1 for metanephrine. The intra-and inter-assay coefficients of variation were 0.7-8.7%, and the respective accuracies were calculated to be 90.8-104.7% and 89.5-104.5% for TF-SPME. Compared with the PFSPE method, the TF-SPME method had a higher extraction efficiency, lower matrix effects and a wider linear range for eight target substances, which ensured higher accuracy of simultaneous detection of all compounds of interest. Therefore, the proposed TF-SPME method can be employed for the high throughput screening for neuroendocrine tumors in a routine clinical setting and other relative research by simultaneous quantitation of urine eight biological monoamines in a single run.

Aquatic environment remediation by atomic layer deposition-based multi-functional materials: A review

Water pollution still poses significant threats to the ecosystem and human health today. The adsorption, advanced oxidation and membranes filtration have been extensively investigated and utilized for aquatic contaminants remediation, and their efficiency is closely correlated with the advanced materials design and fabrication (e.g. adsorbents, catalysts and membranes). Thanks to uniform deposition, three-dimensional conformity and process controllability, the atomic layer deposition (ALD) has emerged as a promising strategy for fabrication of these multifunctional materials, arising their successful application in aquatic contaminants remediation. Therefore, a timely review on ALD-based water treatment materials is highly important to summarize the current opportunity and elucidate unaddressed problems in this field. Herein, in this review, the advantages of ALD process, the superiority of ALD-based materials and the corresponding decontamination performance were analyzed comprehensively, highlighting key advantages offered by this technology.

Development of affinity between target analytes and substrates in surface enhanced Raman spectroscopy for environmental pollutant detection

Environmental pollution has long been a social concern due to the variety of pollutants and their wide distribution, persistence and being detrimental to health. It is therefore necessary to develop rapid and sensitive strategies to trace and detect these compounds. Among various detection methodologies, surface enhanced Raman spectroscopy (SERS) has become an attractive option as it enables accurate analyte identification, simple sample preparation, rapid detection and ultra-high sensitivity without any interference from water. For SERS detection, an essential yet challenging step is the effective capture of target analytes onto the surface of metal nanostructures with a high intensity of enhanced electromagnetic field. This review has systematically summarized recent advances in developing affinity between targets and the surface of SERS substrates via direct adsorption, hydrophobic functional groups, boronate affinity, metal organic frameworks (MOFs), DNA aptamers and molecularly imprinted polymers (MIPs). At the end of this review, technical limitations and outlook have been provided, with suggestions on optimizing SERS techniques for real-world applications in environmental pollutant detection.

Fabrication of edge-curled petals-like covalent organic frameworks and their properties for extracting indole alkaloids from complex biological samples

In this study, a functionalized covalent-organic framework (COF) was first synthesized using porphyrin as the fabrication unit and showed an edge-curled, petal-like and well-ordered structure. The synthesized COF was then introduced to prepare porous organic polymer monolithic materials (POPMs). Two composite POPM/COF monolithic materials with rod shapes, referred to as sorbent A and sorbent B, were prepared in stainless steel tubes using different monomers. Sorbents A and B exhibited relatively uniform porous structures and enhanced specific surface areas of 153.14 m²/g and 80.01 m²/g, respectively. The prepared composite monoliths were used as in-tube solid-phase extraction (SPE) sorbents combined with HPLC for the on-line extraction and quantitative analytical systems. Indole alkaloids (from Catharanthus roseus G. Don and Uncaria rhynchophylla (Miq.) Miq. Ex Havil.) contained in mouse plasma were extracted and quantitatively analyzed using the online system. The two composite multifunctional monoliths showed excellent clean-up ability for complex biological matrices, as well as superior selectivity for target indole alkaloids. Method validation showed that the RSD values of the repeatability (n=6) were ≤ 3.46%, and the accuracy expressed by the spiked recoveries was in the ranges of 99.38%–100.91% and 96.39%–103.50% for vinca alkaloids and Uncaria alkaloids, respectively. Furthermore, sorbents A and B exhibited strong reusability, with RSD values ≤ 5.32%, which were based on the peak area of the corresponding alkaloids with more than 100 injections. These results indicate that the composite POPM/COF rod-shaped monoliths are promising media as SPE sorbents for extracting trace compounds in complex biological samples.

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Edge-curled petals-like COF was synthesized using porphyrin as the fabrication unit.

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In-tube monolithic POMP/COF composite SPE sorbents with rod-shape were fabricated.

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The in-tube sorbents were used to extract hence indole alkaloids from complex samples.

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The two homemade sorbents show strong reusability of more than 100 times.

Development of a sample pretreatment device integrating ultrasonication, centrifugation and ultrafiltration, its application on rapid on-site screening of illegally added chemical components in heat-clearing, detoxicating Chinese patent medicines followed by electrospray ionization-ion mobility spectrometry

In this paper, a simple and rapid sample pretreatment device integrating ultrasonication, centrifugation and ultrafiltration (UCU) was reported for preparation of trace analytes in complex matrices. The UCU device was composed of two parts, A and B. The sample and extraction solvent were put into Part B for ultrasonic extraction. Subsequently, Part A and Part B were integrated and sealed for centrifugation and ultrafiltration. Finally, the ultrafiltrate in Part A was taken out for subsequent detection. After optimization, the device was applied to rapid on-site screening of five illegally added chemical components in heat-clearing and detoxicating Chinese patent medicines by combining with electrospray ionization-ion mobility spectrometry (ESI-IMS). The method showed good performance in terms of linearity with correlation coefficients (R²) above 0.9976 and limits of detection (LODs) in the range of 0.049-0.391 μg mL^-1. The recoveries were from 96.5 % to 100.8 %. The whole analysis process was within 11 min. The proposed method was further compared with other methods reported in the literature and the advantages and considerations were also explored. The results demonstrated that it was a simple, fast and accurate technique. The establishment of this method not only greatly improved the experimental efficiency but also avoided potential sample pollution brought by multiple sample transfer, and could provide a powerful means for rapid on-site analysis of trace analytes in complex matrices.

A fast and selective gas liquid microextraction of semiochemicals for quantitative analysis in plants

A trapping-based gas liquid microextraction (GLME) method coupled with gas chromatography-mass spectrometry (GC-MS) was utilized to qualitatively and quantitatively characterize semiochemicals in plants. The main GLME extraction efficiency associated parameters (heating temperature and extraction time) were optimized. The results obtained from GLME process were compared with those of steam distillation and ultrasonic extraction, and the recovery, peak number and reproducibility were evaluated by using Thuja koraiensis Nakai as a representative plant. Furthermore, the quantitative performances of the GLME in terms of sample amount, recoveries of spiked standards and correlation were systematically evaluated using standard addition method, which gave a good quantitative ability for all the compounds with squares of correlation coefficient (r²) of higher than 0.99. Finally, the contents of α-pinene, camphene, linalool, α-terpinenol, β-caryophyllene, α-caryophyllene, and totarol in Thuja koraiensis Nakai samples were quantified, and their concentrations (SD, n = 3) were; 0.65 (0.06), 0.62 (0.05), 4.12 (0.15), 0.99 (0.08), 1.11 (0.07), 0.63 (0.04), and 21.91 (0.25) μg g^-1, respectively. It was demonstrated that GLME is a powerful sample preparation technique for quantitative and qualitative analysis of plant semiochemicals.

Selective separation and purification of polydatin by molecularly imprinted polymers from the extract of Polygoni Cuspidati Rhizoma et Radix, rats' plasma and urine

Molecularly imprinted polymers (MIPs) based on polydatin were prepared by precipitation polymerization method. Synthesis process of MIPs was optimized by discussion of functional monomers, porogens and the molar ratio of template- functional monomer-cross linker. Then, MIPs were prepared with polydatin as the template, 4-vinyl pyridine as the functional monomer, ethylene glycol dimethyl acrylate as the cross linker, acetonitrile as the porogen and the molar ratio of template-monomer-cross linker at 1:10:20. Scanning electron microscopy and Fourier transform infrared spectrometer were used to inspect macroscale and chemical bond of MIPs. Adsorption capability and selectivity of MIPs to polydatin were investigated by carrying out the static, dynamic and selective experiments. The results showed MIPs performed high adsorption ability and selectivity to polydatin, indicating MIPs could be used to separate and enrich polydatin from the complex systems. Finally, MIPs were applied as the adsorbent for isolation and purification of polydatin from the extract of Polygoni Cuspidati Rhizoma et Radix, rats' plasma and urine samples. MIPs were successfully used to separate polydatin from the Polygoni Cuspidati Rhizoma et Radix and recovery ranged from 89.2% to 91.6%. The maximum concentration of polydatin in rats' plasma and urine samples was 2.84 ± 0.0748 µg mL^-1 and 2.64 ± 0.485 µg mL^-1, respectively. Moreover, to compare with the MIPs method, organic solvent methods were used to analyze the polydatin in rats' plasma and urine samples. The results illustrated MIPs method was effective and selective for enrichment of polydatin from the medicinal plants and biological samples.