Solid-phase Extraction Adsorbent Research Articles

Determination of four cannabinoids in wastewater based on a hyperbranched mixed-mode anion exchange magnetic solid-phase extraction adsorbent combined with UHPLC-MS/MS

Determination of four cannabinoids in wastewater based on a hyperbranched mixed-mode anion exchange magnetic solid-phase extraction adsorbent combined with UHPLC-MS/MS

Novel Mesoporous Cetyltrimethylammonium Bromide-Modified Magnetic Nanomaterials for Trace Extraction and Analysis of Bisphenol Endocrine Disruptors in Diverse Liquid Matrices

In this study, Fe3O4 was used as a magnetic core, combined with the characteristics of mesoporous adsorbents, to prepare a novel magnetic mesoporous composite material named MMC. Cetyltrimethylammonium bromide (CTAB) and tetraethyl orthosilicate (TEOS) were used as functional monomers, and a simple etching method was employed. The resulting MMC was used as an effective adsorbent for the magnetic solid-phase extraction of trace residues of six bisphenol endocrine disruptors (bisphenol A, bisphenol B, bisphenol C, bisphenol F, bisphenol AF, and bisphenol AP) from environmental water and food samples. Characterization results indicated that the surface of MMC exhibited a distinct wormhole-like mesoporous structure, with the successful incorporation of CTAB functional groups and Si-OH. The crystal structure of Fe3O4 remained stable throughout the preparation process. Mapping analysis confirmed the uniform distribution of CTAB functional groups without aggregation and demonstrated high magnetic intensity, enabling rapid separation and collection under an external magnetic field. Extraction and elution conditions were optimized, and tests were conducted for interfering substances such as humic acid, glucose, fructose, and sucrose under optimal parameters. The results showed that recovery rates were not significantly affected. The quality evaluation of the method demonstrated good linearity, a broad linear range, low limits of detection and quantification, and satisfactory recovery rates. Blank and spiked analyses were conducted for seven real samples, including environmental water (rivers and lakes) and food samples (dairy, juice, and carbonated beverages), with satisfactory spiked recovery rates achieved. Thus, the developed analytical method enables the analysis and detection of trace residues of various bisphenol pollutants in complex matrices, such as environmental water and food samples, providing a valuable reference for trace analysis of similar contaminants in complex matrices.

Synthesis of flower-like polyamine/C18 dual-functional magnetic titanium dioxide-based oligopolymer microspheres and their application for the purification, detection and dietary exposure assessment of 52 pesticides in bayberry samples.

Novel core-shell flower-like polyamine/C18 dual-functional magnetic titanium dioxide-based oligopolymer (Fe3O4@fTiO2-PAPMA/C18) microspheres were synthesized and used as a magnetic solid-phase extraction (MSPE) adsorbent to purify 52 pesticides in bayberry samples. The Fe3O4@fTiO2-PAPMA/C18 microspheres were fully characterized and it can obviously improve the purification ability of 52 pesticides in bayberry samples. Coupled to LC-MS/MS, the developed method indicated low limits of detection (LODs) and limits of quantification (LOQs) of 0.1-1.0μg/kg and 0.3-3.0μg/kg, respectively. Recoveries in bayberry samples ranged from 71.1% to 108%, with relative standard deviations (RSDs) of 1.5%∼9.6% at four spiking levels. The established MSPE-LC-MS/MS method was employed to analyze 52 pesticide residues in 374 bayberry samples, and the top five pesticides with the highest detection rate were phenylether metronidazole, pyraclostrobin, carbendazim, imidacloprid and tebuconazole. Furthermore, the risk assessment to the 30 pesticides showed that the levels of pesticides found in bayberry samples do not pose a health risk.

Ecofriendly and biocompatible biochars derived from waste-branches for direct and efficient solid-phase extraction of benzodiazepines in crude urine sample prior to LC-MS/MS.

Biochars (BCs) derived from waste-branches of apple tree, grape tree, and oak were developed for direct solid-phase extraction (SPE) of five benzodiazepines (BZDs) in crude urine samples prior to liquid chromatography-tandem mass spectrometry (LC-MS/MS)determination. Scanning electron microscopy, elemental analyzer, X-ray diffractometry, N2 adsorption/desorption experiments, and Fourier transform infrared spectrometry characterizations revealed the existence of their mesoporous structure and numerous oxygen-containing functional groups. The obtained BCs not only possessed high affinity towards BZDs via π-π and hydrogen bond interactions, but also afforded the great biocompatibility of excluding interfering components from undiluted urine samples when using SPE adsorbents. Variables affecting SPE of target analytes were systematically optimized including pH, ionic strength, dilution ratio, washing solution, desorption solvent, and its volume. The method of BC-based SPE combined with LC-MS/MS exhibited awide linear range of 0.03-100ng/mL, alow detection limit of 0.01-0.08ng/mL, and satisfactory recovery of 77.6-106% for the studied BZDs. Notably, this method allowed the possibility of direct loading of undiluted urine samples and avoided tedious filtration and dilution steps, which significantly simplified the pretreatment process. Additionally, these BC sorbents derived from waste-branches were ecofriendly and cost-effective, providing a sustainable alternative for the traditional SPE sorbents. Thus, the proposed method has promising application for ecofriendly, simple, efficient, and reliable monitoring of BZDs in urine samples.

Preparation of ofloxacin molecularly imprinted polymer Raman sensor based on magnetic graphene oxide.

Ofloxacin is a commonly used quinolone antibiotic that is also used as a feed supplement in livestock production and in plant disease prevention and treatment. However, the excessive use and abuse of ofloxacin will accumulate along the food chain and endanger human health. Therefore, the development of a simple, rapid, and sensitive detection method for the determination of ofloxacin is critical. Herein, a detection method combining molecularly imprinted magnetic solid-phase extraction (MISPE) and surface-enhanced Raman spectroscopy (SERS) was developed for the detection of ofloxacin. Graphene oxide supported by magnetic beads was synthesized by a one-pot method, producing what was subsequently referred to as magnetic graphene oxide (MGO), and a molecularly imprinted membrane was synthesized on its surface by exploiting the ability of dopamine to self-polymerize under alkaline conditions. MGO@MIPs were obtained as the adsorbent for magnetic solid-phase extraction, which was used for the extraction and enrichment of ofloxacin in complex sample matrix, and then quantitative analysis was conducted by SERS. The developed method exhibited an excellent linear relationship with respect to ofloxacin concentration (10-5 to 102μgmL-1), with a detection limit of 9.7 × 10-6μgmL-1 in ultrapure water. Blank honey, milk, and pork samples spiked with ofloxacin at concentrations of 0.005, 0.1, 1, and 10μgmL-1 were extracted and determined using the developed method, with recoveries ranging from 93.1% to 105.6%. The results support the strong application prospects for the method, demonstrating simple and time-efficient operation and high accuracy.

Hydrophilic magnetic polyimide nanocomposite for rapid extraction of phthalate esters from drinking water samples

Phthalate esters (PAEs), a type of widely used plasticizer, tend to migrate from plastic products into drinking water. In this paper, a hydrophilic magnetic Fe3O4/polyimide/polyvinylpyrrolidone (Fe3O4/PI/PVP) nanocomposite was synthesized by simultaneously encapsulating Fe3O4 nanoparticles with PVP in PI via a simple and rapid phase inversion method. The prepared Fe3O4/PI/PVP nanocomposite was used as an adsorbent for magnetic solid-phase extraction (MSPE) to determine 6 PAEs in drinking water samples in combination with GC–MS. Due to the addition of PVP, the nanocomposite has good hydrophilicity and can be easily dispersed in water. The nanocomposite was directly used for extraction without solvent activation, and extraction equilibrium was achieved within 5 min with high extraction recovery. The Fe3O4/PI/PVP nanocomposite-based MSPE/GC–MS method showed great potential for PAE analysis, with a limit of detection of 6 PAEs ranging from 0.006 to 0.167 μg/L and relative standard deviations (RSD) between 0.7 % and 10.9 %. The developed method was successfully applied to determine trace PAEs in several drinking water samples with recoveries ranging from 73.2 % to 118.5 % and RSDs less than 14.0 %. This work provides a new reference for the preparation of hydrophilic magnetic adsorbent materials and a method for the enrichment and separation of PAEs in aqueous matrices.

Efficient enrichment and sensitive determination of endocrine disruptors in PPCPs by novel magnetic covalent organic framework extraction coupled with HPLC-MS/MS.

Endocrine-disrupting chemicals (EDCs) are a growing class of pollutants commonly found in environmental matrices due to their extensive use in pharmaceuticals and personal care products (PPCPs). In this study, a novel magnetic covalent organic framework (COF), Fe3O4-COOH@TFP-BHBD, was successfully synthesized and utilized as an adsorbent for magnetic solid-phase extraction (MSPE) of EDCs from PPCPs. The core-shell structured adsorbent demonstrated a high specific surface area, strong magnetic responsiveness and excellent stability. A COF-MSPE-high-performance liquid chromatography-tandem mass spectrometry (COF-MSPE-HPLC-MS/MS) method was developed for the quantitative analysis of EDCs in PPCPs. Under the optimized condition, the detection and quantification limits of this method reached as low as 0.001-0.007ng/mL and 0.004-0.025ng/mL, respectively. This method was validated and proven capable to analyze real PPCP samples, while the spiked recovery rates in ranged from 85.62 to 107.83% with RSD of 2.28-8.58%. Moreover, the adsorption mechanism was investigated using density functional theory (DFT) calculations. The DFT results revealed that the efficient enrichment capacity of Fe3O4-COOH@TFP-BHBD for EDCs can be attributed to π-π interactions and hydrogen bondings. This proposed method provides excellent adsorption ability and sensitivity for the extraction and precise detection of EDCs in PPCPs.

A stable and reusable aluminum-based metal-organic framework for the effective extraction of four aflatoxins from vegetable oils.

The high specific surface area of metal-organic framework (MOF) materials endows them with efficient adsorption capabilities, thereby facilitating sample purification. In this study, a novel aluminum-based MOF (Al-MOF) was synthesized and employed as a solid-phase extraction (SPE) adsorbent for the purification of aflatoxins B1 (AFB1), AFB2, AFG1, and AFG2 in vegetable oils. It was revealed that Al-MOF adsorbs aflatoxins through hydrogen bonding and π-π interactions. Under optimal SPE conditions, liquid chromatography-tandem mass spectrometry analysis yielded limits of detection ranging from 0.06 to 0.25μg/kg and limits of quantification from 0.21 to 0.84μg/kg for the four aflatoxins. Recovery rates at concentrations of 5, 10, and 20μg/kg ranged from 74% to 110%, with coefficients of variation below 11%. This method achieves efficient and cost-effective purification of aflatoxins in vegetable oils. Compared to national standard methods, this approach offers advantages such as lower material costs, ease of storage, and reusability.

Green synthesis of water-compatible layer-by-layer assembled sandwich bread-like molecularly imprinted polymers for selective recognition of baicalin from Scutellariae Radix.

Molecularly imprinted polymers (MIPs) are typically synthesized in organic solvents, leading to poor compatibility with water, weak affinity and selectivity for target molecules in aqueous media. To address these challenges, a green and sustainable synthesis of sandwich bread-like ATP@MIP was conducted using polyethylenimide (PEI) and deep eutectic solvent (DES) as hydrophilic bi-functional monomers via layer-by-layer self-assembly on the attapulgite (ATP) carrier. The new ATP@MIP can provide a higher density of imprinting sites with more orderly and uniform distribution due to inhibiting the competitive polymerization between PEI and DES, thereby significantly enhancing recognition ability. Moreover, the ATP@MIP was synthesized in water, aligning with green chemistry principles and establishing a sustainable preparation method for MIP materials. Equipped with the remarkable merits of good water compatibility, excellent selectivity (IF=3.6), high adsorption capacity (77.6 mg g-1) and desirable repeatability (8 times), the as-prepared materials were used as a solid phase extraction adsorbent for efficient separation and enrichment of baicalin from Scutellariae Radix. More importantly, the recognizing performance of ATP@MIP for baicalin increased 1.40-1.69 times than other MIP materials, and its excellent specificity was demonstrated in comparison with several common commercial adsorbents (C18, HLB, MCX and SAX). Therefore, this work introduces a feasible and green strategy to synthesize water-compatible MIP materials for highly selective enrichment and separation of active components from natural products.

A Cu/β-cyclodextrin/reduced graphene oxide nanocomposite for efficient and multi-aflatoxin detection in rice, ginger and bean samples.

Aflatoxins (AFs) are some of the most important mycotoxins or fungal toxins that cause contamination of food products and are considered a threat to human and animal health. An efficient Cu/β-cyclodextrin/reduced graphene oxide nanocomposite (Cu/β-CD/rGO) has been prepared and applied as a new solid-phase extraction adsorbent for the separation and preconcentration of four AFs (B1, B2, G1, and G2) using high-performance liquid chromatography with fluorescence detection (HPLC-FLD). The successful synthesis of the prepared nanocomposite was confirmed using Fourier transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), and transmission electron microscopy (TEM). The impacts of pH, amount of adsorbent, sample volume, desorption solvent volume, and salt concentration on the recovery of AFs were precisely investigated and optimized by central composite design (CCD). Under the optimal conditions, the introduced method demonstrated good linearity in the range of 0.4-5.4, 0.08-1.08, 0.4-5.4, and 0.08-1.08 ng g-1 for AFs B1, B2, G1 and G2, respectively. The limits of detection and quantification for the four AFs were obtained in the range of 0.06-0.53 and 0.20-1.62 ng g-1, respectively. The accuracy of the method was evaluated using recovery measurements in spiked real samples such as rice, bean, and ginger samples, and satisfactory recoveries were obtained in the range of 83.5-109.0% with good precision (RSDs between 2.4 and 8.6%). The results of this research revealed that our developed method is sensitive, highly effective, and convenient to perform for the trace analysis of AFs in different real samples.

Facile and rapid preparation of fluorinated imprinted adsorbent for magnetic solid phase extraction of liquid-crystal monomers.

Anew fluorinated imprinted adsorbent (MIA) for magnetic solid phase extraction (MSPE) ofliquid crystal monomer (LCM) pollutantswas one-pot prepared within 3.5h using 4-[difluoro(3,4,5-trifluorophenoxy)methyl]-3,5-difluoro-4'-ethyl-biphenyl (DFBP) as template and 1H,1H,2H,2H-heptadecafluorodecyl acrylate/vinylanthracene as dual monomers. The structure, morphology, and magnetic properties of MIA fabricated were investigated by various characterization techniques. Under the optimal conditions the prepared MIA presented satisfactory specific recognition performance. The recognition factor and adsorption capacity towards DFBP were 2.7 and 15.9mg/g, respectively. The specific recognition behaviors of MIA/MSPE towards DFBP were surveyed by means of adsorption kinetics and adsorption isotherms. Combining MSPEwith HPLC coupled to a diode array detector (DAD), asensitive, reliable and anti-interference method for the monitoring of LCMs residuals in various environmental water and soil samples was established. The achieved enrichment factors were 132-248 and 96-204 in water and soil samples, respectively. The corresponding limits of detection were 0.0017-0.0051μg/L and 0.087-0.28μg/kg, respectively. Moreover, confirmatory experiments were adopted to inspect the accuracy of theestablished MIA/MSPE-HPLC/DAD approach. To the best of our knowledge, this is the first time that an imprinted material has been used forspecific isolation and capture of LCMs which have been classified as emerging organic pollutants.

Synthesis of reusable hierarchical Pore PVDF-MIL-101(Cr) foam for Solid phase extraction of fluoroquinolones from water and its adsorption behavior for anionic and cationic dyes

In this study, a novel hierarchical pore MIL-101(Cr) foam (HPF-MIL-101) was designed and prepared using the sacrificial template method with NaCl as the sacrificial template. This method involved grinding, heating, and washing the NaCl template to produce HPF-MIL-101, with PVDF as the binder and MIL-101(Cr) as the adsorbent. This preparation process is both straightforward and cost-effective, avoiding the use or generation of any organic reagents, thereby offering an environmentally sustainable approach for producing metal-organic framework (MOF) composites. The prepared HPF-MIL-101 exhibited excellent adsorption capabilities for both anionic dye (methyl orange, MO) and cationic dye (methylene blue, MB). The adsorption process followed a pseudo-second-order kinetic model and Friedrich isotherm model, indicating a multilayer adsorption. This is further supported by the Weber-Morris intraparticle diffusion model, which divided the adsorption process into three stages. Furthermore, the adsorption process was consistent with the Freundlich isotherm model, with a correlation coefficient (r) greater than 0.96. HPF-MIL-101 can also be used as an adsorbent for solid phase extraction (SPE). Therefore, an SPE method combined with high-performance liquid chromatography (HPLC) was developed using HPF-MIL-101 as the adsorbent to analyze five fluoroquinolones (FQs) in water samples. This analytical method showed good linearity in the range of 30–2000 ng·mL−1, with excellent linear correlation coefficient (r = 0.9991–0.9999), reasonable extraction recoveries ranging from 80.39 to 112.7 % (RSD ≤ 7.9 %), and low limits of detection (8–30 ng·mL−1). Overall, the results indicated that HPF-MIL-101 not only had a simple, environment-friendly, and pollution-free preparation process but also can be reused for enrichment and detection of trace FQs in water. Thus, HPF-MIL-101 exhibits immense application potential in environmental pollutant removal and also provides a valuable reference for the preparation and application of other MOF composites.

Rapid and enhanced detection of sulfonamide antibiotic using task-specific ionic liquids nanoconfined in tunable nanoporous carbons.

The development of a novel multifunctional adsorbent for the sensitive detection and capture of antibiotic residues in environmental and food samples presents a significant challenge. In this study, we synthesized a pioneering nanocomposite, ILs@PC, by encapsulating task-specific ionic liquids (ILs) within nitrogen-doped porous carbon (PC) derived from metal-triazolate frameworks. This ILs@PC nanocomposite functions as a multifunctional adsorbent in dispersive solid-phase extraction (DSPE), enabling simultaneous sorptive removal, sensitive detection, and molecular sieve selection. The ILs@PC demonstrated enhanced adsorption efficiency and sensitivity for sulfonamide antibiotics (SAs) compared to the pristine PC, attributed to the nanoconfinement effect of the ILs and the influence of pore volume on this effect. When integrated with high-performance liquid chromatography (HPLC), the ILs@PC-based DSPE method achieved a detection limit of 0.75-1.88μgL-1 for SAs, along with satisfactory recoveries of 86.0%-111.9%. Additionally, a portable syringe device was developed to facilitate rapid on-site extraction and enrichment of SAs. The practicality of this method was validated through its successful application in detecting SAs in real samples, including lake water and milk. This approach highlights its potential for efficient and rapid monitoring of antibiotic residues in both environmental and food systems.

Hydrophilic-lipophilic balance copolymer composite nanofiber as an adsorbent for online solid phase extraction of three estrogens from water samples with column-switching prior to high-performance liquid chromatography

BackgroundIn recent years, the increasing accumulation of estrogen pollutants in the environment has raised concerns about their impact on human health, necessitating the development of highly sensitive detection methods for trace pollutant enrichment and analysis in environmental samples. Online pretreatment detection technology offers significant advantages over conventional offline techniques, including high automation, minimal human intervention, and improved efficiency. However, the key to successful implementation lies in the advancement of novel adsorbent materials. ResultsHerein, we present a novel adsorbent material called polyacrylonitrile-hydrophilic-lipophilic balanced copolymer (PAN-HLB) composite nanofiber prepared via electrospinning for efficient online packed fiber solid phase extraction (PFSPE) of three estrogens from water samples. A rapid and highly sensitive online PFSPE-HPLC-FLD method was developed for the quantification of 17 β-Estradiol (E2), Estriol (E3), and 17-ethinylestradiol (EE2). The curves of the target analytes were prepared with good correlation coefficient values (r2 > 0.9900) in the range of 0.1–2 ng/mL. The limit of detection (S/N = 3) was 0.05 ng/mL, the limit of quantitation (S/N = 10) is 0.1 ng/mL. The recoveries of three estrogens were 94.0 %∼110.3 %, and the precisions (RSD) were less than 5 %. The online PFSPE column, packed with the PAN-HLB composite nanofiber, exhibits exceptional stability and can be effectively reused for a minimum of 100 cycles. SignificanceThis study presents the successful preparation of PAN-HLB composite nanofiber for the first time, demonstrating their efficacy as an innovative online pretreatment adsorbent. The proposed online pretreatment and detection approach offers remarkable benefits in terms of sensitivity, labor-saving, and cost-effectiveness that make it highly suitable for practical water sample analysis.

MCM-41 based dispersive micro-solid phase extraction of selected cephalosporin antibiotic residues from water samples prior to liquid chromatographic quantification

The occurrence of antibiotics in water bodies is of concern owing to the serious risk they pose to the environment, water security, aquatic organisms, and human health. In this study, mesoporous silica (MCM-41) nanostructured material was synthesised and characterized by various analytical techniques to determine its morphology and dimension, functional groups, surface charge, and textural properties. The nanostructured MCM-41 was used as an adsorbent in ultrasound-assisted dispersive micro solid-phase extraction (UA-D-µ-SPE) of cefadroxil (CFDX) and cephalexin (CPLX) in water samples. The concentration of the analytes in aqueous solution and real water samples was determined using high-performance liquid chromatography coupled with diode array detection (HPLC-DAD). The developed method for CFDX and CPLX in various water samples exhibited relative linear ranges of 0.1–600 µg/L and 0.1–550 µg/L, respectively, and correlation coefficients ranging from 0.9923–0.9993. Under optimum condition, the UA-D-µ-SPE/HPLC-DAD method displayed low limits of detection (LOD) and quantification (LOQ), with values ranging from 0.02–0.16 µg/L and 0.067–0.53 µg/L, respectively. The investigated intraday and interday accuracy in spiked water samples showed acceptable extraction efficiencies with a range of 73.5–98.1% and a relative standard deviation less than 6.0%. Moreover, the performance of MCM-41 was also assessed for the removal of cephalosporin antibiotics aqueous solutions. The kinetic and isotherm studies revealed that the adsorption process followed pseudo-second order and the Langmuir model, respectively. Furthermore, the maximum adsorption capacities for CFDX and CPLX were 43.2 and 47.8 mg/g. Lastly, the UA-D-µ-SPE/HPLC-DAD method was successfully applied in extracting, preconcentrating, separating and determining CFDX and CPLX in wastewater and surface water samples. These results demonstrated that MCM-41 can be applied in the removal of cephalosporin antibiotics from aquatic environments.

Uniform spherical covalent organic framework for efficient extraction of 13 per-and polyfluoroalkyl substances in Chinese medicinal materials

Long-term consumption or exposure to Chinese medicinal materials contaminated with per- and polyfluoroalkyl substances (PFASs) poses a potential risk to human health. Owing to the low contents of PFASs in the complex matrix of Chinese medicinal materials, it is imperative to develop high-performance adsorbents for the enrichment of PFASs prior to analysis. Covalent organic frameworks (COFs) are widely used as adsorbents because of their large surface area and good chemical stability. In this study, CN bonded spherical TPB-DMTP-COF was prepared by a simple Schiff base reaction using acetonitrile as solvent at room temperature. The materials exhibited abundant porous structures, exceptional hydrophobicity, superb thermostability, excellent crystalline structure, and a substantial surface area of 1419 m2 g−1 and thus could be outstanding adsorbents for solid-phase extraction (SPE) of PFASs. The adsorption experiments showed that the adsorption capacity and adsorption rate of PFASs increased with the extension of alkyl carbon chain of PFASs molecule. In essence, the strong adsorption affinity could be attributed to the hydrophobic characteristics and Van der Waals force. The proposed approach based on SPE and liquid chromatography-tandem mass spectrometry achieved low limits of detection (0.01–0.04 μg kg−1), good precision (< 4.7%) and excellent linearity for PFASs ranging from 0.1 to 10 ng mL−1 (R2 ≥ 0.997). The actual amounts of PFASs varied from 0.08 μg kg−1 to 2.67 μg kg−1 in seven Chinese medicinal materials. The satisfactory recoveries (91.6%–105.8%) and good repeatability (12 times) for simultaneous analysis of 13 PFASs were obtained. This research presents a promising alternative for the sensitive analysis of PFASs at trace levels in complex matrices.

Synthesis of β-cyclodextrin magnetic-graphene-oxide pyrenyl (β-mGOP) gels for high-throughput enrichment and detection of various trace mycotoxins in food using UHPLC-cIMS

In this research, β-cyclodextrin magnetic-graphene-oxide pyrenyl gel composite (β-mGOP) was employed to remove trace mycotoxins from food products. The β-mGOP gels exhibited a three-dimensional macroporous structure that facilitated the rapid diffusion of target molecules into the nanoporous structure of the covalent organic frameworks embedded within the gel. The adsorption process of mycotoxins onto the β-mGOP gels conformed to the pseudo-second-order kinetics and the Freundlich adsorption model. These findings demonstrated exceptional rapid adsorption kinetics without pore collapse, making the material suitable as fillers for solid-phase extraction adsorbents. Additionally, a novel screening technique utilizing β-mGOP gels in conjunction with cyclic ion mobility mass spectrometry was developed to illustrate the efficacy of β-mGOP gels in capturing various trace substances in food and enhancing detection resolution. The versatile, uncomplicated, and scalable characteristics of β-mGOP gels indicate their promising potential for future applications in high-throughput analysis of trace contaminants in food.

Developing a novel pyridine-based ionic porous organic polymer with functional group for highly efficient extraction of phenolic endocrine disruptors in natural water and tilapia fish

A pyridine-based ionic porous organic polymer bearing hydroxyl groups (OH-iPOP) was developed for the first time by quaternization and crosslinking of 4-pyridinemethanol with 4,4′-bis(chloromethyl)biphenyl. OH-iPOP exhibited strong adsorption capacity for endocrine disruptors (EDs) including bisphenol A, bisphenol F, p-tert-butylphenol and bisphenol B (82.59–183.9 mg g−1), much higher than that of commercial adsorbents. The adsorption mechanism of OH-iPOP to EDs involved π-π⁎ interaction, hydrogen bond and electrostatic interaction. Using OH-iPOP as solid phase extraction adsorbent combined with high-performance liquid chromatography, a reliable method for the sensitive detection of trace EDs in natural water and tilapia fish was established. The detection limits (S/N = 3) were 0.01–0.04 ng mL−1 and 1.00–3.80 ng g−1 for natural water and tilapia fish, respectively. The method recoveries ranged from 81.5 % to 116 %. This work not only develops an efficient adsorbent for the enrichment of EDs, but also provides a new strategy for the synthesis of novel cationic POPs.

Methylated magnetic covalent organic framework for sample preparation and LC-MS/MS detection of 12 tadalafil analogs in dietary supplements

Tadalafil analogs are often illegally added to dietary supplements such as herbal beverages, protein powders and tablet foods. Due to the complexity of the matrices, effective extraction of tadalafil analogs is the key to achieve accurate quantification. Therefore, it is of great significance to establish a rapid and effective method for the analytical determination of tadalafil analogs in complex matrices. In this study, a novel methylated magnetic covalent organic framework, Fe3O4@TFPB-OT, was successfully synthesized under mild conditions. Fe3O4@TFPB-OT demonstrated robust adsorption capabilities, with capacities ranging from 52.4 to 90.9 mg/g for the tadalafil analogs. Several pre-enrichment parameters were optimized, including adsorbent dosage, extraction time, pH, shaking time, elution solvent, and desorption time. The applicability of Fe3O4@TFPB-OT was evaluated as effective adsorbents for the magnetic solid-phase extraction (MSPE) of 12 tadalafil analogs in dietary supplements. Combined with high-performance liquid chromatography-tandem mass spectrometry, the limits of detection (LODs) of this method ranged from 0.005 to 0.05 μg/L in liquid matrices and from 0.005 to 0.05 μg/kg in solid matrices, showing good sensitivity and recoveries ranged from 56.1 % to 90.9 %with relative standard deviations lower than 3.9 %, demonstrating good accuracy and precision. Additionally, the adsorbent retained its effectiveness after at least ten reuse cycles, indicating significant reusability. This study provides an effective method for the analysis and detection of tadalafil analogs in dietary supplements and has great potential for application.

Solid phase extraction-surface enhanced Raman spectroscopy (SPE-SERS) test of antibiotic residues in Milk based on au@ MIL-101 NPs

A SPE-SERS method was developed for the detection of several antibiotic residues in dairy products. Gold nanoparticles (Au NPs) encapsulated with an ultrathin Cr-MIL-101 shell (Au@Cr-MIL-101 NPs) have been synthesized, and the thickness of Cr-MIL-101 shell can be precisely controlled to 3 nm. As a superior solid phase extraction (SPE) adsorbent, Cr-MIL-101 acts as a shell layer to effectively enrich antibiotics within the localized surface plasmon resonance (LSPR) field of Au NPs, which enhances the SERS signal and eliminates background interference. The method can achieve highly sensitive and high-throughput detection for tetracycline hydrochloride, sulfapyridine and benzylpenicillin sodium in dairy products, and the detection limits (LOD) are as low as 2.237, 2.644 and 4.662 ppb respectively. The recoveries of antibiotic residues in spiked dairy products ranged from 72.31 % to 146.7 % with matrix effects (ME) of −15.13 % to 28.68 %. Thus, this method holds significant promise for rapid detection of antibiotics in milk.