Triazine-based porous organic polymer as pipette tip solid-phase extraction adsorbent coupled with HPLC for the determination of sulfonamide residues in food samples

Molecularly imprinted polymers-coated magnetic covalent organic frameworks for efficient solid-phase extraction of sulfonamides in fish

In this study, covalent organic frameworks (COFs) were grown in situ on magnetic nitrogen-doped graphene foam (MNGF), and the resulting composite of COFs-modified MNGF (MNC) was wrapped by molecularly imprinted polymers (MNC@MIPs) for specifically capturing SAs. A magnetic solid phase extraction (MSPE) method for SAs was established using MNC@MIPs with good magnetic responsiveness. The adsorption performance of MNC@MIPs was superior to that of non-molecularly imprinted polymers (MNC@NIPs), with shorter adsorption/desorption time and higher imprinting factors. A high-efficiency SAs analytical method was developed by fusing HPLC and MNC@MIPs-based MSPE. This approach provides excellent precision, a low detection limit, and wide linearity. By analyzing fish samples, the feasibility of the approach was confirmed, with SAs recoveries and relative standard deviations in spiked samples in the ranges of 77.2-112.7 % and 2.0-7.2 %, respectively. This study demonstrated the potential use of MNC@MIPs-based MSPE for efficient extraction and quantitation of trace hazards in food.

A ternary heterostructure aptasensor based on metal-organic framework and polydopamine nanoparticles for fluorescent detection of sulfamethazine

Residue of sulfamethazine (SMZ), a typical short-acting drug to prevent bacterial infections, in food is a threat to human health. A ternary heterogeneous metal-organic framework hybrid (Zn/Fe-MOF@PDANSs) of Zn-TCPP-MOF, MIL-101 (Fe) and polydopamine nanoparticles (PDANSs) was proposed to establish an aptasensor for the sensitive and selective detection of SMZ. In this sensor, Zn-TCPP-MOF and FAM emitted fluorescence at 609 nm and 523 nm, respectively, and the fluorescence of FAM-ssDNA could be quenched when it was adsorbed on the surface of MOF hybrid. In the presence of SMZ, the fluorescence of FAM-ssDNA recovered due to the dropping from MOF hybrid, while the fluorescence of MOF hybrid remained. With this strategy, a wide concentration range and high sensitivity of SMZ were detection. And the ternary Zn/Fe-MOF@PDANSs sensor exhibited more excellent performance than binary Zn/Fe-MOF aptasensor. In addition, the sensor showed pleasurable selectivity, and was utilized for SMZ determination in authentic chicken and pork samples, implying the fascinating potential in practical application.

Ratiometric fluorescent determination of sulfadimethoxine in foods based on a dual-emission metal-organic framework

Ratiometric fluorescence detection is endowed with higher accuracy than single fluorescence signal assay. In this work, we construct a ratiometric fluorescence probe for the facile quantification of sulfadimethoxine (SDM) in foods. By wrapping N-doped carbon dots (N-CDs) and gold nanoclusters (AuNCs) into zeolitic imidazolate framework-8 (ZIF-8), the nanocomposite of N-CDs/AuNCs@ZIF-8 is facilely prepared and emits two fluorescence including 475 nm from N-CDs and 650 nm from AuNCs. Since bovine serum albumin (BSA) is the stabilizer of AuNCs, SDM can form a complex with BSA, resulting in the fluorescence quenching of AuNCs at 650 nm by a static quenching mechanism. In contrast, SDM has a rare influence on the fluorescence of N-CDs (475 nm). As a result, the use of the probe of N-CDs/AuNCs@ZIF-8 for SDM detection enables simultaneous measurement of response signal and reference signal. Under the optimal condition, the SDM assay based on the probe has a good linear relationship within 10 to 2 × 106 ng/mL and the limit of detection (LOD) is low to 1.064 ng/mL. In addition, the fluorescent probe shows good reliability for the detection of SDM in practical food samples.

Fluoranthene slow down sulfamethazine migration in soil via π-π interaction to increase the abundance of antibiotic resistance genes

Sulfonamide antibiotics and polycyclic aromatic hydrocarbons (PAHs) often coexist in soil, leading to compound pollution through various pathways. This study focuses on sulfamethazine (SMZ) and PAHs (fluoranthene) as the subject for compound pollution research. Using a soil-groundwater simulation system, we investigated the migration characteristics of SMZ under coexistence with fluoranthene (Fla) and observed variations in the abundance of antibiotic resistance genes (ARGs). Through molecular docking simulations and isothermal adsorption experiments, we discovered that Fla bound with SMZ via π-π interactions, resulting in a 20.9% increase in the SMZ soil-water partition coefficient. Under compound conditions, the concentration of SMZ in surface soil could reach 1.4 times that of SMZ added alone, with an 13.4% extension in SMZ half-life. The deceleration of SMZ's vertical migration rate placed additional stress on surface soil microbiota, leading to a proliferation of ARGs by 66.3%-125.8%. Moreover, under compound pollution, certain potential hosts like Comamonadaceae and Gemmatimonas exhibited a significant positive correlation with resistance genes such as sul 1 and sul 2. These findings shed light on the impact of PAHs on sulfonamide antibiotic migration and the abundance of ARGs. They also provide theoretical insights for the development of technologies aimed at mitigating compound pollution in soil.

Development of a Novel SPME Coating for Efficient Extraction of Organochlorine Pesticides in Liquid Dairy Products

A sensitive and accurate analysis of organochlorine pesticide (OCP) residues in dairy products poses a significant challenge. Herein, a novel covalent organic polymer, Azo-COP-1, was synthesized for the enhanced extraction of OCPs in dairy products. The solid phase microextraction fiber coated with Azo-COP-1 demonstrated excellent extraction performance for the OCPs via hydrogen bonding, halogen bonding, π-π stacking, and electrostatic interactions. Coupled with gas chromatography-electron capture detection, we developed a facile and reliable method for detecting OCPs in six types of dairy products with low limits of detection (2.0-400 pg g-1) and high method recoveries (82.6-113%). Azo-COP-1 coatings exhibited good stability and durability. The results verified the feasibility of using Azo-COP-1-based SPME to extract OCP residues in dairy product samples, highlighting its potential for routine monitoring of pesticide residues and food safety assessments.

The determination of 11 sulfonamide antibiotics in water and foods by developing a N-rich magnetic covalent organic framework combined with ultra-high performance liquid chromatography-tandem mass spectrometry

The concentration of antibiotic residues in water and animal-derived foods is low and the matrix is complex, and effective extraction of antibiotic residues in them is a key factor for accurate quantification. It is important to establish a rapid and effective method for the analytical determination of antibiotics in water and foods. In this study, a type of novel magnetic COF (Fe3O4@SiO2@PDE-TAPB-COF) was synthesized and characterized. Moreover, Fe3O4@SiO2@PDE-TAPB-COF combined with ultra-high performance liquid chromatography-tandem mass spectrometry was used to determine the 11 sulfonamide antibiotics (SAs) in water and food. The parameters including pH, adsorption amount, adsorption time, type of elution solvent and elution time were optimized. Under the optimal conditions, the standard curves of 11 SAs showed good linearity (R 2 > 0.999) in their respective concentration ranges and had lower detection and quantification limits. The spiked recoveries of the developed MSPE-UPLC-MS/MS method for the 11 SAs in water and foods were 74.3-107.2% and 75.1-102.5%, respectively. And the relative standard deviations (RSDs) were less than 9.56% (n = 7). The results indicated that the method can be used for the determination of SAs in foods and water with low detection limits and high sensitivity.

Advancements and greenification potential of magnetic molecularly imprinted polymers for chromatographic analysis of veterinary drug residues in milk

Milk, as a widely consumed nutrient-rich food, is crucial for bone health, growth, and overall nutrition. The persistent application of veterinary drugs for controlling diseases and heightening milk yield has imparted substantial repercussions on human health and environmental ecosystems. Due to the high demand, fresh consumption, complex composition of milk, and the potential adverse impacts of drug residues, advanced greener analytical methods are necessitated. Among them, functional materials-based analytical methods attract wide concerns. The magnetic molecularly imprinted polymers (MMIPs), as a kind of typical functional material, possess excellent greenification characteristics and potencies, and they are easily integrated into various detection technologies, which have offered green approaches toward analytes such as veterinary drugs in milk. Despite their increasing applications and great potential, MMIPs' use in dairy matrices remains underexplored, especially regarding ecological sustainability. This work reviews recent advances in MMIPs' synthesis and application as efficient sorbents for veterinary drug extraction in milk followed by chromatographic analysis. The uniqueness and effectiveness of MMIPs in real milk samples are evaluated, current limitations are addressed, and greenification opportunities are proposed. MMIPs show promise in revolutionizing green analytical procedures for veterinary drug detection, aligning with the environmental goals of modern food production systems.

A review on carbon-based biowaste and organic polymer materials for sustainable treatment of sulfonamides from pharmaceutical wastewater

Frequent detection of sulfonamides (SAs) pharmaceuticals in wastewater has necessitated the discovery of suitable technology for their sustainable remediation. Adsorption has been widely investigated due to its effectiveness, simplicity, and availability of various adsorbent materials from natural and artificial sources. This review highlighted the potentials of carbon-based adsorbents derived from agricultural wastes such as lignocellulose, biochar, activated carbon, carbon nanotubes graphene materials as well as organic polymers such as chitosan, molecularly imprinted polymers, metal, and covalent frameworks for SAs removal from wastewater. The promising features of these materials including higher porosity, rich carbon-content, robustness, good stability as well as ease of modification have been emphasized. Thus, the materials have demonstrated excellent performance towards the SAs removal, attributed to their porous nature that provided sufficient active sites for the adsorption of SAs molecules. The modification of physico-chemical features of the materials have been discussed as efficient means for enhancing their adsorption and reusable performance. The article also proposed various interactive mechanisms for the SAs adsorption. Lastly, the prospects and challenges have been highlighted to expand the knowledge gap on the application of the materials for the sustainable removal of the SAs.

One-pot derivatization/magnetic solid-phase extraction coupled with liquid chromatography-fluorescence detection for the rapid determination of sulfonamide residues in honey

Consuming foods with excess sulfonamide residues threatens human health, underscoring the importance of their detection in food. This study presents an innovative one-pot derivatization/magnetic solid-phase extraction (OPD/MSPE) method for sulfonamides analysis. This approach integrates the derivatization and extraction steps into a single process. The sample solution, along with the derivatization reagent fluorescamine and the sorbent magnetic hydroxyl multi-walled carbon nanotubes, is mixed and vortexed for 3 min. This procedure simultaneously conducts derivatization and extraction, with easy phase separation using an external magnet. This streamlined sample preparation method is completed in only 5 min and, when combined with liquid chromatography-fluorescence detection (LC-FLD), demonstrates excellent linearity (R2 > 0.99) and satisfactory detection limits (0.004-0.04 ng/g) for the quantification of nine sulfonamides in honey samples. The proposed OPD/MSPE-LC-FLD method is distinguished by its simplicity, rapidity, high sensitivity, and specificity, making it an outstanding advancement in the field of food safety analysis.

Preparation and evaluation of a tryptophan based hypercrosslinked porous polymer as an efficient adsorbent for pipette tip solid-phase extraction of sulfonamides

A novel tryptophan-based porous polymer is designed and synthesized via a facile one-step hypercrosslinking polymerization process, and applied as sorbent for extraction of trace sulfonamides in foodstuffs. The developed polymer has high surface area, large conjugate system, and abundant functional groups (e.g., π-π stacking, hydrogen bonding, hydrophobic and electrostatic attraction interactions), which endow it with superior affinity and high adsorption capacity for sulfonamides (16.16-59.29 mg g-1). The optimized SPE method is coupled with HPLC-DAD to create a sensitive and efficient protocol that provides good linearity (R2 ≥ 0.9979), low limits of detection, satisfactory recoveries (92.5-109.5 %) and high precisions (RSDs < 8.24). In addition, the newly proposed method greatly reduces the amount of adsorbent (2.0 mg) and organic solvent (2.0 mL) used. Adsorption kinetics, isotherms, and simulation calculations studies further reveal the presence of monolayer adsorption, chemical adsorption process, and multiple interactions. Thus, this work presents a polymer capable of multiple interactions for the pretreatment of trace sulfonamides in foodstuffs.

What Are We Eating? Surveying the Presence of Toxic Molecules in the Food Supply Chain Using Chromatographic Approaches

Consumers in developed and Western European countries are becoming more aware of the impact of food on their health, and they demand clear, transparent, and reliable information from the food industry about the products they consume. They recognise that food safety risks are often due to the unexpected presence of contaminants throughout the food supply chain. Among these, mycotoxins produced by food-infecting fungi, endogenous toxins from certain plants and organisms, pesticides, and other drugs used excessively during farming and food production, which lead to their contamination and accumulation in foodstuffs, are the main causes of concern. In this context, the goals of this review are to provide a comprehensive overview of the presence of toxic molecules reported in foodstuffs since 2020 through the Rapid Alert System for Food and Feed (RASFF) portal and use chromatography to address this challenge. Overall, natural toxins, environmental pollutants, and food-processing contaminants are the most frequently reported toxic molecules, and liquid chromatography and gas chromatography are the most reliable approaches for their control. However, faster, simpler, and more powerful analytical procedures are necessary to cope with the growing pressures on the food chain supply.

Fabrication of a biochar-doped monolithic adsorbent and its application for the extraction and determination of coumarins from Angelicae Pubescentis Radix

A monolithic adsorbent was designed aiming to the structure of osthole and columbianadin, and fabricated using diallyl phthalate as the monomer and ethylene dimethacrylate as the crosslinker with the addition of bamboo biochar, via polymerization reaction in a stainless-steel tube. The prepared composite adsorbent packed in the tube was used as a solid-phase extraction column for the extraction and determination of two coumarins (osthole and columbianadin) in Angelicae Pubescentis Radix, combing with a C18 analytical column through an HPLC instrument, which show excellent matrix-removal ability and good selectivity to osthole and columbianadin. Furthermore, the present adsorbent shows good applicability, which was used for the extraction of osthole from Duhuo Jisheng Pill. Compared to the commercial C18 and phenyl adsorbent, the present adsorbent own better selectivity and higher resolution. These results attributed to the enhanced specific surface area (141 m2/g) and enriched interaction sites of the resulting composite adsorbent, due to the doping of bamboo biochar, which can produce hydrogen bond, dipole-dipole, π-π and hydrophobic force interactions with the osthole and columbianadin. The methodology validation indicated that the present method showed good precision and good accuracy, and the composite adsorbent showed good preparative repeatability, which can be reused for no less than 100 times with the relative standard deviation ≤4.6 % (n = 100). The present work provided a simple and efficient method for the extraction and determination osthole and columbianadin from Angelicae Pubescentis Radix.

Synthesis of azo-linked covalent organic polymers for pipette tip solid-phase extraction of sedative residues from animal tissues samples

Azo-linked covalent organic polymers (ACOPs) were synthesized by a simple azo reaction, with 2,2'-bis(trifluoromethyl)benzidine and 1,3,5-trihydroxybenzene as the monomers. The preparation process was mild, green, and environmental-friendly, avoiding the use of high temperature, metal catalysis, and harmful organic reagent. The obtained ACOPs were characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, thermogravimetric analysis, powder X-ray diffraction, and Brunauer-Emmett-Teller. With the prepared ACOPs as adsorbent, a method of pipette tip solid-phase extraction-liquid chromatography-tandem mass spectrometry detection (PTSPE-LC-MS/MS) was proposed for the analysis of target sedatives in animal tissues. Furthermore, the parameters for the extraction of five sedatives, including the amount of adsorbent, pH value, ion strength, elution solvent and volume, were investigated. Under the optimized conditions, the linear dynamic range was found from 0.1 to 10.0 μg kg-1, and the limits of detection were ranged from 0.02 to 0.1 μg kg-1. The method was assessed by the analysis of target sedatives in animal tissues, and the recoveries for the spiked pork muscle and pork liver samples were 84-102% and 83-101%, respectively. The results show that the developed method of PTSPE-LC-MS/MS with ACOPs as adsorbent is efficient for the analysis of trace sedatives in animal tissues.

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.

Azophenyl Calix[4]arene Porous Organic Polymer for Extraction and Analysis of Triphenylmethane Dyes from Seafood

Porous organic polymers (POPs) based on calix[4]arene with a hydrophobic π-rich cavity and host-guest recognition properties exhibit a wide application range of molecular extraction and separation. However, it is still a challenge to improve the extraction and separation selectivity by exploring and seeking appropriate building blocks for the functionalization and pore size adjustment of calix[4]arene. Herein, an azophenyl calix[4]arene porous organic polymer (AC-POP) was proposed. By introducing an electron-rich cavity and adjusting the pore sizes of calix[4]arene, the AC-POP showed high selectivity extraction performance in triphenylmethane (TPM) dyes. The extraction mechanism was explored by adsorption thermodynamics study, density functional theory (DFT) calculation, and reduced density gradient (RDG) and electrostatic potential (ESP) analyses, which suggested that the selectivity adsorption of TPM dyes based on AC-POP was mainly the result of entropy driven by the hydrophobic effect. In addition, the noncovalent interactions including π-π stacking, van der Waals force, and electrostatic interaction were also important factors affecting the adsorption capacity of TPM dyes. Under optimal extraction conditions, the AC-POP possessed a maximum extraction amount of 95.3 mg·g-1 for Rhodamine B (RB), high enrichment factor of about 100, and excellent reusability more than 10 times. Then, an analytical method of TPM dyes with AC-POP as a solid-phase extractant combined with high-performance liquid chromatography-ultraviolet (HPLC-UV) was established, which displayed excellent sensitivity with the limits of detection (LODs) and limits of quantitation (LOQs) in the ranges of 0.004-0.35 and 0.016-1.16, respectively. The mean recoveries for TPM dyes ranged from 85.0 to 109.4% with an RSD of 0.48-9.45%. The proposed method was successfully applied to the analysis of the five TPM dyes in seafood matrix samples.

A new approach of magnetic field application in miniaturized pipette-tip extraction for trace analysis of four synthetic hormones in breast milk samples

Herein, a novel homemade electrical device was designed, including two pieces of external neodymium magnets, providing a reciprocating magnetic field to introduce a magnetic-assisted dispersive pipette-tip micro solid-phase extraction. To evaluate the performance efficiency of the proposed method, a novel magnetic calcined GO/SiO₂@Co-Fe nanocube sorbent was synthesized, filled into the pipette-tip, exposed to the reciprocating magnetic field, and applied for the preconcentration of some hormone therapy drugs in human biological matrices. The effective adsorption and desorption parameters were optimized using a rotatable central composite design and one-variable-at-a-time approaches. Under the optimized conditions, the target analytes' detection limits were found to be below 0.02 ng mL^-1. Moreover, the calibration curves were linear in the range of 0.03-500.00 ng mL^-1 (R² > 0.9966), with RSDs% less than 7.8 %. Eventually, the established method was applied to extract the analytes from breast milk samples, followed by LC-ESI-MS/MS analysis.

Fluorine-Functionalized Triazine-Based Porous Organic Polymers for the Efficient Adsorption of Aflatoxins

Food safety issue caused by aflatoxins has aroused widespread concern in society. Herein, a novel fluorine-functionalized triazine-based porous organic polymer (F-POP) was developed for the first time by the simple condensation polymerization of 2,2'-bis(trifluoromethyl)benzidine and cyanuric chloride. With in-built fluorine functional group (F) and imine group (-NH-), F-POP displayed significantly superior adsorption ability for aflatoxins, outperforming fluorine-free POP due to the multiple interaction mechanisms of hydrogen bond, F-O interaction, π-π interaction, F-π interaction, and hydrophobic interaction. Thus, magnetic F-POP was prepared by introducing Fe₃O₄ into F-POP and then utilized as a magnetic sorbent for the extraction of trace aflatoxins in peanut and rice samples prior to high-performance liquid chromatography-fluorescence detection. Under the optimal conditions, the proposed method presented high sensitivity with the limit of detections at 0.005-0.15 ng g^-1. F-POP also exhibited outstanding adsorption capability for many other organic pollutants, revealing its great potential for analysis or adsorption applications.