Magnetic solid phase extraction of sulfonamides based on carboxylated magnetic graphene oxide nanoparticles in environmental waters

Preparation of cylindrical Chitosan/β-Cyclodextrin/MIL-68(Al) foam column for solid-phase extraction of sulfonamides in water, urine, and milk

This study describes the preparation of a cylindrical polymer foam column termed Chitosan/β-Cyclodextrin/MIL-68(Al) (CS/β-CD/MIL-68(Al)). An ice template-freeze drying technique was employed to prepare the CS/β-CD/MIL-68(Al) foam column by embedding MIL-68(Al) in a polymer matrix comprising cross-linked chitosan (CS) and β-cyclodextrin (β-CD). The cylindrical CS/β-CD/MIL-68(Al) foam was subsequently inserted into a syringe to develop a solid phase extraction (SPE) device. Without the requirement for an external force, the sample solution passed easily through the SPE column thanks to the porous structure of the CS/β-CD/MIL-68(Al) foam column. Moreover, the CS/β-CD/MIL-68(Al) foam column was thought to be a superior absorbent for SPE since it included the adsorptive benefits of CS, β-CD, and MIL-68(Al). The SPE was utilized in conjunction with high-performance liquid chromatography to analyze six sulfonamides found in milk, urine, and water. With matrix effects ranging from 80.49 % to 104.9 % with RSD values of 0.4-14.0 %, the method showed high recoveries ranging from 80.6 to 107.4 % for water samples, 93.4-105.2 % for urine, and 87.4-100.9 % for milk. It also demonstrated good linearity in the range of 10-258 ng·mL-1 with the limits of detection ranging from 1.88 to 2.58 ng·mL-1. The cylindrical CS/β-CD/MIL-68(Al) foam column prepared in this work offered several advantages, including its simple fabrication, excellent water stability, absence of pollutants, biodegradability, and reusability. It is particularly well-suited for SPE. Furthermore, the developed SPE method, employing CS/β-CD/MIL-68(Al) foam column, is straightforward and precise, and its benefits, including affordability, ease of preparation, lack of specialized equipment, and solvent economy, underline its broad applicability for the pretreatment of aqueous samples.

Sacrificial template synthesis of hollow sulfonate group functionalized microporous organic network for efficient solid phase extraction of sulfonamide antibiotics from milk and honey samples

The highly conjugated and hydrophobic characteristics of microporous organic networks (MONs) have largely impeded their broad applications in sample pretreatment especially for the polar or ionic analytes. In this work, a novel uniform hollow shaped sulfonate group functionalized MON (H-MON-SO3H-2) was synthesized via the sacrificial template method for the efficient solid phase extraction (SPE) of sulfonamides (SAs) from environmental water, milk, and honey samples prior to HPLC analysis. H-MON-SO3H-2 exhibited large specific surface area, penetrable space, good stability, and numerous hydrogen bonding, electrostatic, hydrophobic and π-π interaction sites, allowing sensitive SPE of SAs with wide linear range (0.150-1000 μg L-1), low limit of detection (0.045-0.188 μg L-1), good precisions (intra-day and inter-day RSD < 7.3%, n = 5), large enrichment factors (95.7-98.5), high adsorption capacities (250.4-545.0 mg g-1), and satisfactory reusability (more than 80 times). Moreover, the established method was successfully applied to extract SAs from spiked samples with the recoveries of 86.1-104.3%. This work demonstrated the great potential of H-MON-SO3H-2 in the efficient SPE of trace SAs in complex environmental water and food samples and revealed the prospect of hollow MONs in sample pretreatment.

Ultrasensitive and selective detection of sulfamethazine in milk via a Janus-labeled Au nanoparticle-based surface-enhanced Raman scattering-immunochromatographic assay

Sulfamethazine (SM2) is an antibacterial drug，which has been extensively used in human and veterinary medicine, long-term consumption of which may lead to the accumulation of sulfonamides in the body. Detection of sulfonamides often uses microbiological approaches, mass spectrometry and chromatography, which are expensive and time-consuming. Surface-enhanced Raman scattering-based immunochromatographic assay (SERS-ICA) has been recently applied in the detection. Herein, a Janus-labeled Au nanoparticle with subnanosized SiO2-monoclonal antibody and SERS reporter (DTNB) modified simultaneously (mAbAuNpDTNB) has been developed in a SERS-based lateral flow immunosensor, which can be used for rapid, quantitative and ultrasensitive detection of sulfamethazine residue in milk. The mAbAuNpDTNB exhibits a specific array on a paper stripe, which not only identifies sulfamethazine but also straightforwardly exposes the Raman reporter between the AuNps via self-assembly. The detection sensitivity of SERS-ICA for sulfamethazine reached 0.1 pg/mL, which was far below the previously published value by ELISA and the maximum residue limit set by the European Union. The entire SERS-ICA detection for sulfamethazine was completed within 15 min. Furthermore, high accuracy for this assay was exhibited in the spiking experiment with a recovery percentage of 88.1%-112.7%. The results demonstrated that this SERS-ICA can potentially be applied in point-of-care testing as an ultrasensitive and quantitative to semi-quantitative analytical method.

An Automated Solid-Phase Extraction-UPLC-MS/MS Method for Simultaneous Determination of Sulfonamide Antimicrobials in Environmental Water

The large-scale use of sulfonamide antimicrobials in human and veterinary medicine has seriously endangered the ecological environment and human health. The objective of this study was to develop and validate a simple and robust method for the simultaneous determination of seventeen sulfonamides in water using ultra-high performance liquid chromatography-tandem mass spectrometry coupled with fully automated solid-phase extraction. Seventeen isotope-labeled internal standards for sulfonamides were used to correct matrix effects. Several parameters affecting extraction efficiency were systematically optimized, and the enrichment factors were up to 982-1033 and only requiring about 60 min per six samples. Under the optimized conditions, this method manifested good linearity (0.05-100 μg/L), high sensitivity (detection limits: 0.01-0.05 ng/L), and satisfactory recoveries (79-118%) with acceptable relative standard deviations (0.3-14.5%, n = 5). The developed method can be successfully utilized for the determination of 17 sulfonamides in pure water, tap water, river water, and seawater. In total, six and seven sulfonamides were detected in river water and seawater, respectively, with a total concentration of 8.157-29.676 ng/L and 1.683-36.955 ng/L, respectively, and sulfamethoxazole was the predominant congener.

Trace-level detection of sulfonamide antibiotics using quaternary ammonium polymeric ionic liquid-based effervescence-enhanced dispersive solid-phase extraction followed by LC-DAD analysis in environmental waters

Conventional ionic liquids possess several disadvantages, such as high viscosity, difficult sampling/retrieval, and great loss in aqueous solution, limiting their wide applications in the pretreatment field. To solve these drawbacks, we synthesized a quaternary ammonium polymeric ionic liquid (PIL) and pressed it into an effervescent tablet for developing an effervescence-enhanced dispersive solid-phase extraction method (QAP-EDSE). The pressed effervescent tablet was composed of PIL as an extractant, tartaric acid as an acidic source, NaHCO₃ as an alkaline source, and water-soluble starch as a filler, respectively. Under the CO₂-driven dispersion, the QAP-EDSE method integrated rapid enrichment, extraction, and dispersion into one synchronous step. Employing the one-factor-at-a-time approach, several important variables were optimized as follows: 200 mg of P[VBTHEA]Cl as sorbent, 400 μL of acetone as elution solvent, 5 min of elution, solution pH 9.0, and 1 : 1.25 molar ratio of alkaline to acidic sources. Combining LC-DAD analysis, this proposed approach offered the limits of detection as low as 0.11–0.31 μg L⁻¹ and satisfactory recoveries of 81.40–102.62% for five sulfonamides (SAs) in environmental waters. The lower relative standard deviations (1.9–6.7%) evidenced the higher intraday and interday experimental precision by this method. Overall, the newly developed method is environmentally benign, time-saving, and easy to operate with low detection limit and high recovery and thus shows excellent prospects in the trace-level detection of SAs in environmental waters.

An effervescent tablet-assisted dispersive solid-phase extraction based on the utilization of quaternary ammonium poly ionic liquids (PIL) was proposed for the concentration/extraction of sulfonamides (SAs) in river and lake water samples.

Exploration of an imine-based covalent organic framework for the solid phase extraction of nitroimidazoles in milk and meat samples

TAPT-AN-COF, an imine-based covalent organic framework, was synthesized by a solvothermal method of 2,4,6-trihydroxy-benzene-1,3,5-tricarbaldehyde (TP) and 4,4',4″-(1,3,5-Triazine-2,4,6-triyl)trianiline (TAPT). The structure was characterized and tested by several techniques, revealing that the material had good stability and high specific surface area. The adsorption experiment demonstrates that the adsorption isotherm of TAPT-AN-COF followed the Freundlich isothermal equation, while its adsorption kinetics conformed to the pseudo second-order kinetic model. After characterization, the prepared TAPT-AN-COF was used to separate and enrich nitroimidazoles (NDZs) in milk and meat as the solid-phase extraction (SPE) adsorbent. The effects of adsorbent dosage, pH value, washing solvent, elution solvent type and volume on recoveries were studied. Under the optimal conditions, a method for the determination of NDZs in milk and meat samples was established based on high performance liquid chromatography-ultraviolet detection(HPLC-UVD).The result showed that NDZs had good linearity in the concentration range of 25-500 µg·kg^-1, and the determination coefficients (r²) were all above 0.99. When spiked at 25, 50 and 125 µg·kg^-1, the recoveries of three kinds of food samples ranged from 64.5% to 85.3%, the limits of detection (LODs) were between 2 and 10 µg·kg^-1, and the relative standard deviations were all below 15.9%. In addition, the recoveries of NDZs didn't decrease significantly after being reused for 6 times, showing that TAPT-AN-COF has excellent reusability. Compared with HLB and MCX sorbents, TAPT-AN-COF had better extraction efficiency and qualified purification efficiency. The established method had a satisfying performance on the determination of NDZs in food samples.

Multisensory Systems Based on Perfluorosulfonic Acid Membranes Modified with Polyaniline and PEDOT for Multicomponent Analysis of Sulfacetamide Pharmaceuticals

The degradation of sulfacetamide with the formation of sulfanilamide leads to a deterioration in the quality of pharmaceuticals. In this work, potentiometric sensors for the simultaneous determination of sulfanilamide, sulfacetamide and inorganic ions, and for assessing the degradation of pharmaceuticals were developed. A multisensory approach was used for this purpose. The sensor cross-sensitivity to related analytes was achieved using perfluorosulfonic acid membranes with poly(3,4-ethylenedioxythiophene) or polyaniline as dopants. The composite membranes were prepared by oxidative polymerization and characterized using FTIR and UV-Vis spectroscopy, and SEM. The influence of the preparation procedure and the dopant concentration on the membrane hydrophilicity, ion-exchange capacity, water uptake, and transport properties was investigated. The characteristics of the potentiometric sensors in aqueous solutions containing sulfanilamide, sulfacetamide and alkali metals ions in a wide pH range were established. The introduction of proton-acceptor groups and π-conjugated moieties into the perfluorosulfonic acid membranes increased the sensor sensitivity to organic analytes. The relative errors of sulfacetamide and sulfanilamide determination in the UV-degraded eye drops were 1.2 to 1.4 and 1.7 to 4%, respectively, at relative standard deviation of 6 to 9%.

Synthesis of the Magnetically Nanoporous Organic Polymer Fe3O4@SiO2-NH2-COP and Its Application in the Determination of Sulfonamide Residues in Surface Water Surrounding a Cattle Farm

Efficient extractions of trace antibiotic residues in the environment are a key factor for accurate quantification of the residues. A new nanoporous material, namely, magnetically covalent organic polymer (MCOP, Fe₃O₄@SiO₂-NH₂-COP) was synthesized in this work and was used for magnetic solid-phase extraction (MSPE). The combination of MSPE with high-performance liquid chromatography separation together with ultraviolet detection (HPLC-UV) was established as an effective method for the determination of four sulfonamide (SA) residues in surface water surrounding a cattle farm. The synthesized magnetic material was characterized by SEM, TEM, FT-IR, magnetic properties measurement system (MPMS), and nitrogen gas porosimetry. The material possessed many attractive features, such as a unique microporous structure, a larger specific surface area (137.93 m²·g⁻¹) than bare Fe₃O₄ (24.84 m²·g⁻¹), high saturation magnetization (50.5 emu·g⁻¹), open adsorption sites, and high stability. The influencing parameters, including pH, the used amount of MCOPs, the type of eluent, adsorption solution, and desorption time, were optimized. Under the optimized conditions, the method conferred good linearity ranges (R² ≥ 0.9990), low detection limits (S/N = 3, LOD, 0.10–0.25 μg·L⁻¹), and satisfactory recoveries (79.7% to 92.2%). The enrichment factor (EF) for the four SAs was 34.13–38.86. The relative standard deviations of intraday (n = 5) and of interday (n = 3) were less than 4.8% and 8.9%, respectively. The equilibria between extraction and desorption for SAs could be reached within 150 s. The proposed method was sensitive and convenient for detecting SA residues in complex environmental matrices, and the successful application of the new MCOPs as an adsorbent was demonstrated.

3DG Functionalized Magnetic Solid Phase Extraction Materials for the Efficient Enrichment of Hexamethylenetetramine in Vermicelli

Solid phase extraction (SPE) is regarded as the most effective purification method for complex matrix samples owing to its simplicity of operator, time-saving, high accuracy, and environmental friendliness. SPE technology is still affected by the high cost of commercial SPE columns and poor adsorption selectivity. Hence, the development of low-cost and highly selective adsorbents is quite challenging and demanding in SPE. In this study, a novel 3DG functionalized magnetic solid phase extraction materials was prepared based on “thiol-ene” click chemistry. The structure, morphology, thermal stability, and magnetic properties of the magnetic composites were studied by Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), thermogravimetric analysis (TGA), and vibrating sample magnetometer (VSM). Then the adsorption performance of composite was determined by static adsorption experiments, which showed fast binding kinetics (100 min) and good adsorption performance (Q_e= 65.34 mg/g). Moreover, these magnetic nanoparticles were used as adsorbents for magnetic solid phase extraction (MSPE) and coupled with high-performance liquid chromatography (HPLC) for separation and detection of illegally added hexamethylenetetramine in vermicelli. As for practical application, the recoveries for the spiked samples in the concentration range of 8–40 μg/g were between 83.24–92.69%, and the RSD was between 0.20–2.07%.

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.

Preparation of molecularly imprinted resin/polydopamine nanofibers mat for the highly efficient extraction and determination of sulfonamides in environmental water

With polyacrylonitrile nanofibers mat (PAN NFsM) as a template, molecularly imprinted resin/polydopamine nanofibers mat (MIR/PDA NFsM) was synthesized for the extraction of sulfonamides (SAs) in water. The specific surface area and pore volume were increased obviously due to the functionalization of MIR. The adsorption efficiencies of MIR/PDA NFsM under optimized conditions for SAs were 92.3-99.3%. Possible adsorption mechanisms of imprinting recognition and hydrogen bond interactions were also put forward. Compared with MIR particles, the MIR/PDA NFsM exhibited much superior adsorption performance. Particularly, the outstanding mass transfer efficiency of MIR/PDA NFsM was much higher than the other reported adsorbents for SAs. Finally, a new method based on the solid-phase extraction (SPE) of MIR/PDA NFsM was successfully developed for the detection of five SAs in environmental water with HPLC-MS/MS and applied to the analysis of actual samples. Under the selected conditions, the enrichment factors of MIR/PDA NFsM of SCP, SMT, SMZ, SMR, and SMX were between 23.0 and 25.0. Low detection limits (0.26-0.76 ng L^-1), broad linear range (1.0 ng L^-1 to 10.0 μg L^-1), and satisfactory recoveries (82.8-115.6%) and precisions (RSDs < 7.2%) were obtained. Moreover, the excellent reusability properties and storage stability endowed MIR/PDA NFsM with great value for practical applications.

A nanocomposite adsorbent of metallic copper, polypyrrole, halloysite nanotubes and magnetite nanoparticles for the extraction and enrichment of sulfonamides in milk

A composite adsorbent composed of metallic copper (Cu), polypyrrole (PPy), halloysite nanotubes (HNTs) and magnetite nanoparticles (Fe₃O₄) was developed to extract and enrich sulfonamides by dispersive magnetic solid phase extraction. The composite could adsorb sulfonamides via hydrogen bonding and hydrophobic, π-π and π-electron-metal interactions. The extraction conditions were optimized and the developed composite adsorbent was characterized and provided a large surface area that enhanced extraction efficiency for sulfonamides. Coupled with high performance liquid chromatography, the adsorbent was used to quantitatively determine sulfonamides found in milk samples. The response of the developed method exhibited linearity from 5.0 to 150.0 μg kg^-1 for sulfathiazole, and from 2.5 to 100.0 μg kg^-1 for sulfamerazine, sulfamonomethoxine and sulfadimethoxine. Limits of detection were between 2.5 and 5.0 μg kg^-1. Recoveries of sulfonamides in milk samples ranged from 83.0 to 99.2% with RSDs lower than 6%. The developed composite adsorbent showed good reproducibility and reusability.

The in situ catalytic oxidation of sulfamethoxazole via peroxydisufate activation operated in a NG/rGO/CNTs composite membrane filtration

Metal-free carbonaceous composite membranes have been proven to effectively drive novel in situ catalytic oxidation for the degradation of organic pollutants via persulfates activation. In this study, nitrogen-doped graphene (NG) was employed as a modifier to enhance the catalytic activity of the carbon mats by assembly with reduced graphene oxide (rGO) and carbon nanotubes (CNTs) on the top of a nylon supporter. The morphology and performance of the NG/rGO/CNTs composite membrane were compared to those obtained without the addition of NG (rGO/CNTs). Owing to the larger nanochannels for water delivery and stronger hydrophobicity on the surface, the NG/rGO/CNTs composite membrane shows a superior low-pressure filtration performance in favor of energy-saving operation. For the in situ catalytic oxidation of the NG/rGO/CNTs composite membrane through the activation of peroxydisufate (PDS), the average removal rate of sulfamethoxazole (SMX), one of frequently detected sulfonamide antibiotics in water, can reach 21.7 mg·m^-2·h^-1 under continuous filtration mode, which was 17% more rapid than that of the rGO/CNTs, resulting in significant detoxifying of the oxidation intermediates. Owing to the addition of NG into the carbon mats, the reactive nitrogen-doped sites identified by X-Ray photoelectron spectroscopy (XPS), such as pyridinic and graphitic N, played important roles in PDS activation, while both the radical and non-radical pathways were involved in in situ catalytic oxidation. According to the experimental evidence of the effects that solution environment has on the SMX removal and transmembrane pressure, the NG/rGO/CNTs composite membrane shows a relatively high resistance to changes in the solution pH, chloride ion inhibition, and background organics fouling. These results suggest a new approach to the application of activated persulfate oxidation in water treatment, such that improvements to the reaction stability warrant further investigation.

A novel dispersive magnetic solid phase microextraction using ionic liquid-coated amino silanized magnetic graphene oxide nanocomposite for high efficient separation/preconcentration of toxic ions from shellfish samples

A novel dispersive magnetic solid phase microextraction (d-MSPE) method using ionic liquid-coated amino silanized magnetic graphene oxide (MGO@SiO₂-APTES-IL) as adsorbent has been established for enriching and extracting lead(II), copper(II) and cadmium(II) in shellfish samples. The novel nanocomposite was proved synthesized successfully by various characterization technologies. Parameters that could affect the recoveries of target ions were investigated and optimized focusing on adsorption and desorption using Box-Behnken design of response surface methodology (BBD-RSM). The limits of detection (LODs) for three target heavy metal ions were 2.42, 3.36, 3.75 ng L^-1, respectively. Additionally, the maximum adsorption capacities of the nanocomposite for target ions were 251.23, 138.51, 159.31 mg g^-1 at 298 K, respectively, the nanoadsorbent can be regenerated without significant adsorption capacities loss for four times. These observations revealed that the novel nanocomposite can be used as an excellent adsorbent for separation and preconcentration of the target ions.

High-Coverage Screening of Sulfonamide Metabolites in Goat Milk by Magnetic Doped S Graphene Combined with Ultrahigh-Performance Liquid Chromatography-High-Resolution Mass Spectrometry

Currently, there are more than 1000 varieties of synthetic sulfonamides universally used as antibiotics causing severe results of potential carcinogenicity and drug resistance for human health due to excessive residue of animal-derived food. A facile and novel approach for untargeted screening of sulfonamides (SAs) and metabolites was proposed based on magnetic solid-phase extraction-ultrahigh-performance liquid chromatography-tandem high-resolution mass spectrometry (MSPE-UHPLC-HRMS). Compared with QuEChERS without the clean-up procedure and SPE in terms of matrix effect and absolute recovery, magnetic doped S graphene (S-doping level: 2.82%) synthesized via a solid-state microwave approach and the aggregation wrap mechanism was used as a novel adsorbent for nonspecific extraction of desired analytes by the noncovalent interaction between electron-deficient thiophene sulfur and electron donors such as amino or amide as well as π-π stacking interactions. Combined with variable data-independent acquisition, characteristic fragment-ion filtering (m/z 156.01138 or m/z 108.04439) and assignment of extracted-ion chromatograms of marked fragment ions were successfully utilized to screen the desired analytes and subsequently confirmed with the availability of reference standards. The optimized and validated approach for spiked 26 SAs and 9 metabolites in control goat milk demonstrated satisfactory accuracy (80.1-112.6%) and precision (RSDs < 6.4%) for matrix-matched standard addition. After applying suspect goat milk samples, untargeted SA analytes including sulfanilamide or an N⁴-acetylsulfamethazine metabolite with concentration ranging from 66.3 to 398.5 ng L^-1 were determined in 5 of 45 goat milk samples.

Highly sensitive determination of endocrine disrupting chemicals in foodstuffs through magnetic solid-phase extraction followed by high-performance liquid chromatography-tandem mass spectrometry

BACKGROUND

Endocrine disrupting chemicals (EDCs), proved to be potential carcinogenic threats to human health, have received great concerns in food field. It was essential to develop effective methods to detect EDCs in food samples. The present study proposed an efficient method to determine trace EDCs including estrone (E1), 17β-estradiol (E2), estriol (E3) and bisphenol A (BPA) based on magnetic solid-phase extraction (MSPE) coupled high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) in meat samples.

RESULTS

Fe₃ O₄ @COF(TpBD)/TiO₂ nanocomposites were synthesized via functionalization of magnetic covalent organic frameworks (COFs) with titanium dioxide (TiO₂ ) nanoparticles, and used as absorbents of MSPE to enrich EDCs. The efficient EDCs enrichment relies on π-π stacking interaction, hydrogen bonding, and the interaction between titanium ions (IV, Ti⁴⁺ ) and hydroxyl groups in EDCs, which improves the selectivity and sensitivity. Under the optimized conditions, target EDCs were rapidly extracted through MSPE with 5 min. Combining Fe₃ O₄ @COF(TpBD)/TiO₂ based MSPE and HPLC-MS/MS to determine EDCs, good linearities were observed with correlation coefficient (R² ) ≥ 0.9989. The limits of detection (LODs) and limits of quantification (LOQs) were 0.13-0.41 μg kg^-1 and 0.66-1.49 μg kg^-1 , respectively. Moreover, the proposed method was successfully applied to real samples analysis.

CONCLUSIONS

The established MSPE-HPLC-MS/MS method was successfully applied to determine EDCs in meat samples with rapidness, improved selectivity and sensitivity. It shows great prospects for EDCs detection in other complicated matrices. © 2020 Society of Chemical Industry.

Covalent organic framework Schiff base network-1-based pipette tip solid phase extraction of sulfonamides from milk and honey

In this work, a covalent organic framework Schiff base network-1 (SNW-1), was synthesized based on the Schiff base reaction between terephthalaldehyde and melamine and characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray diffraction and nitrogen adsorption-desorption isotherm analyses. The prepared SNW-1 was employed as pipette tip solid phase extraction adsorbent for the extraction of sulfonamides (SAs) prior to high performance liquid chromatography analysis. The parameters affecting the extraction efficiency, including the salt concentration, sample pH, amount of adsorbent, and types and volume of eluent were investigated in detail. Good linearities were obtained between the peak area and SAs concentration ranging from 5 to 500 ng mL^-1 with correlation coefficients (R²) higher than 0.9998. The limits of detection and RSDs were lower than 0.25 ng mL^-1 and 1.9 %, respectively. The developed method was further applied for the determination of SAs in milk and honey samples with recoveries in the range of 85.8 % - 118.0 % and RSDs less than 9.5 %. The results demonstrate that the SNW-1 shows great potential for the enrichment of trace SAs in complex matrices.

Synthesis of magnetic metal organic framework/covalent organic framework hybrid materials as adsorbents for magnetic solid-phase extraction of four endocrine-disrupting chemicals from milk samples

RATIONALE

Endocrine-disrupting chemicals (EDCs), widespread and easily ingested through the simple food chain, have been suggested to pose potential carcinogenic threats to human health. Considering food safety and public health, it is urgent to establish a sensitive and effective method to enrich and determine EDCs in food samples.

METHODS

Novel hybrid nanocomposites Fe₃ O₄ @A-TpBD@NH₂ -MIL-125(Ti) were synthesized through the formation of amide bonds. The as-prepared Fe₃ O₄ were innovatively encapsulated with 4-aminobenzoic acid functionalized COF(A-TpBD) to generate bare carboxyl (-COOH), which formed amide bonds with the NH₂ -MIL-125(Ti), generating well-defined and hierarchical hybrid materials. The Fe₃ O₄ @A-TpBD@NH₂ -MIL-125(Ti) materials were used as the adsorbents for magnetic solid-phase extraction (MSPE) coupled with high-performance liquid chromatography/tandem mass spectrometry (HPLC/MS/MS) to enrich and determine EDCs (E1, E2, E3 and BPA) from milk samples.

RESULTS

Fe₃ O₄ @A-TpBD@NH₂ -MIL-125(Ti) exhibited improved adsorption efficiency and selectivity based on π-π stacking interaction, hydrogen bonding, electrostatic interaction, and the interaction between the hydroxyl group in EDCs and titanium ions (IV, [Ti]⁴⁺ ). Under the optimized conditions, Fe₃ O₄ @A-TpBD@NH₂ -MIL-125(Ti)-based MSPE coupled with HPLC/MS/MS showed good linearity with correlation coefficient (R² ) ≥0.9983 and high sensitivity with limits of detection (LODs) in the range of 0.37-0.85 μg/L. Moreover, the developed method was successfully employed to detect EDCs in milk samples.

CONCLUSIONS

Fe₃ O₄ @A-TpBD@NH₂ -MIL-125(Ti) possess good adsorption capability and selectivity for EDCs. In addition, the proposed MSPE-HPLC/MS/MS method based on Fe₃ O₄ @A-TpBD@NH₂ -MIL-125(Ti) is effective and sensitive for the determination of EDCs in real samples, which can be used as a robust alternative method to monitor EDCs in complex matrices.

Surface modification of coconut shell activated carbon for efficient solid-phase extraction of N-nitrosodimethylamine from water

A practical and cheap methodology in modifying commercial coconut shell activated carbon for solid-phase extraction of N-nitrosodimethylamine in water was developed through an understanding of activated carbon surface chemistry. In comparison with commercial activated carbon, extraction recoveries by activated carbon treated with sulfuric acid decreased by 50%, while those of activated carbon heated at 800°C improved by more than 100%. Acid treatment increased the oxygen content on the carbon's surface. In contrast, heat treatment decreased the surface oxygen content, resulting in a more hydrophobic surface, which favoured adsorption and extraction of N-nitrosodimethylamine. The influence of different activated carbon sizes, amount of modified activated carbon, and pH on the N-nitrosodimethylamine recoveries was assessed and compared with the commercial solid-phase extraction cartridge. The recommended amount of powder activated carbon treated at 800°C was 3 g to yield an optimum recovery of 130%, which was superior to the commercial solid-phase extraction cartridges. The method validation results confirmed the high accuracy, reproducibility, and precision of the method. The study indicated that chemisorption plays a significant role in the adsorption of N-nitrosodimethylamine on activated carbon, and the optimization of its surface chemistry can enhance N-nitrosodimethylamine adsorption/extraction from water.

β-Cyclodextrin-/AuNPs-functionalized covalent organic framework-based magnetic sorbent for solid phase extraction and determination of sulfonamides

β-Cyclodextrin-functionalized magnetic covalent organic framework (Fe₃O₄@COF@Au-β-CD) was developed as sorbent for magnetic solid phase extraction of trace sulfonamides in meat samples prior to HPLC-MS/MS analysis. The sorbent was synthesized by loading gold nanoparticles onto a Fe₃O₄@COF surface and then functionalized by thiolated-β-cyclodextrin immobilization via Au-S bonding formation. The prepared composite material was employed for sulfonamides extraction. The main parameters were optimized to obtain the best extraction efficiency. The experiments of adsorption kinetics were carried out to investigate the adsorption mechanism. Results showed the pseudo-second-order kinetic was better fitted with the adsorption kinetics of sulfonamides. Under optimized conditions, the magnetic solid phase extraction-HPLC method showed good linearity (R² ≥ 0.9936), and the limits of detection were in the range of 0.8-1.6 μg kg^-1. The proposed method was successfully used for quantitation of sulfonamides in real samples. The recoveries ranged from 78.9 to 112.0% with relative standard deviations (RSDs) < 10% (n = 5). The proposed method exhibited great potential for enrichment and determination of sulfonamides in many other food or environment samples. Graphical abstract.

Assembling 3D hierarchical hollow flower-like Ni@N-doped graphitic carbon for boosting simultaneously efficient removal and sensitive monitoring of multiple sulfonamides

The excessive accumulation of sulfonamides (SAs) drugs makes it imperative to develop novel materials for boosting simultaneously efficient removal and precise monitoring of multiple SAs. Herein, three-dimensional hollow flower-like Ni@nitrogen-doped graphitic carbon (3DHFNi@NGC) was designed/fabricated via a facile one-pot hydrothermal route and subsequent pyrolysis. The resultant 3DHFNi@NGC exhibits a unique 3D hollow hierarchical architecture assembled by a layer-by-layer interlacing of corrugated nanosheets subunits, thereby affording numerous interconnected channels, available internal/external surfaces as well as suitable interior cavities. By virtue of its special architecture and in-situ generated N-doped graphitic carbon along with good magnetism, the 3DHFNi@NGC demonstrates superior sorption performance towards SAs, accompanied by high total saturated adsorption capacity, fast sorption rate and easy magnetic recycling. It is noteworthy that as-constructed 3DHFNi@NGC also exhibits high-sensitive/simultaneous detection of trace multiple SAs combined high performance liquid chromatography (HPLC), together with a low detection limit (0.035-0.071 ng mL^-1) and a broad linear range (0.2-100 ng mL^-1) as well as high enrichment factors (252 < EFs < 291). These indicate that the smart 3DHFNi@NGC could be a promising candidate for the synchronous remediation and sensitive detection of multiple SAs in aqueous systems, presenting a viable option for sewage treatment and water quality monitoring.

A twin enrichment method based on dispersive liquid-liquid microextraction and field-amplified sample injection for the simultaneous determination of sulfonamides

A twin enrichment method based on offline dispersive liquid-liquid microextraction (DLLME) coupled with online field-amplified sample injection (FASI) was developed for the simultaneous determination of four sulfonamide (SA) antibiotics, including sulfamethazine (SMZ), sulfamerazine (SMR), sulfadizine (SDZ) and sulfacetamide (SFA), in different environmental waters, followed by capillary electrophoresis (CE). Various parameters that affected the separation performance of CE and the enrichment efficiencies of DLLME and FASI were optimized in detail, and excellent CE separation was attained within 6 min. The DLLME-FASI-CE offered high sensitivity enrichment factors of 206, 166, 185 and 150 for SMZ, SMR, SDZ and SFA, respectively. Highly sensitive detection was realized with low limits of detection (LODs), which ranged from 2.0-23.0, 2.2-26.0 and 4.3-63.0 ng mL-1 in tap water, lake water and seawater, respectively, as well as limits of quantification (LOQs) within 6.0-63.0, 7.4-96.0 and 14.0-201.0 ng mL-1, respectively. Satisfactory recoveries in the range of 91-108% were obtained with the three spiked environmental water samples, and the relative standard deviations were from 1.09-7.45%. The simple effective twin enrichment method provided promising perspective for CE determination of SAs in complicated aqueous matrices, with rapidity, sensitivity, and accuracy.

Trends in sensitive detection and rapid removal of sulfonamides: A review

Sulfonamides in environmental water, food, and feed are a major concern for both aquatic ecosystems and public health, because they may lead to the health risk of drug resistance. Thus, numerous sensitive detection and rapid removal methodologies have been established. This review summarizes the sample preparation techniques and instrumental methods used for sensitive detection of sulfonamides. Additionally, adsorption and photocatalysis for the rapid removal of sulfonamides are also discussed. This review provides a comprehensive perspective on future sulfonamide analyses that have good performance, and on the basic methods for the rapid removal of sulfonamides.

Magnetic porous carbons derived from cobalt(ii)-based metal–organic frameworks for the solid-phase extraction of sulfonamides

A highly porous magnetic C/Co-SIM-1 carbon obtained via a simple carbonization process as a promising material for the simultaneous extraction of sulfonamides.

Pipette-tip solid-phase extraction using cetyltrimethylammonium bromide enhanced molybdenum disulfide nanosheets as an efficient adsorbent for the extraction of sulfonamides in environmental water samples

Surfactant cetyltrimethylammonium bromide enhanced molybdenum disulfide was used as an adsorbent in pipette-tip solid-phase extraction for the pretreatment of sulfonamides in environmental water samples. The factors affecting the extraction recoveries of the analytes, including the sample pH value, amount of sorbent, type and volume of eluent solution, and salt concentration were optimized. This pipette-tip solid-phase extraction method demonstrated good linearity (0.05-10.0 µg/L) with a coefficient of determination of 0.9984-0.9996, limit of detection (0.2-0.4 ng/L) and limit of quantitation (0.5-1.0 ng/L), good analyte recoveries (76-91), and acceptable limit of quantitation (<10%) under the optimized conditions. These results indicated that the proposed method was a good tool for monitoring sulfonamides in environmental water samples.

Graphene oxide-Fe3O4 nanocomposite magnetic solid phase extraction followed by UHPLC-MS/MS for highly sensitive determination of eight psychoactive drugs in urine samples

Graphene oxide-Fe₃O₄ (GO-Fe₃O₄) nanocomposite was synthesized by a facile chemical co-precipitation method. The GO-Fe₃O₄ was used as magnetic sorbent to extract the eight psychoactive drugs from urine samples. The analytes are morphine (MOR), 6-monoacetylmorphine (6-MAM), amphetamine (AMP), methamphetamine (MAMP), codeine, cocaine, dolantin and benzoylecgonine (BZE), which were determined by ultrahigh performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS). This method has high selectivity for the target analytes. The limit of detection (LOD) and limit of quantification (LOQ) were 0.02-0.2 μg L^-1 and 0.05-0.5 μg L^-1, respectively. The Mandel's fitting test revealed good linearity within all linear ranges. The linear ranges were calculated as 0.05-1000 μg L^-1 for AMP, MAMP, cocaine and dolantin; 0.1-1000 μg L^-1 for 6-MAM and codein; and 0.5-1000 μg L^-1 for MOR and BZE. The recoveries ranged in 80.4-105.5%. The intra-day and inter-day RSDs are in the range of 2.7-13.1% and 3.9-13.7%, respectively. Magnetic solid phase extraction (MSPE) with GO-Fe₃O₄ provides a convenient, rapid and green sample pretreatment method for extracting the target psychoactive drugs from urine. This methodology can be used for simultaneous or individual detection of eight major psychoactive drugs with high sensitivity. This method has high potential in clinical and forensic areas for psychoactive drugs analysis.

Fabrication of hydrophilic multilayer magnetic probe for salivary glycopeptidome analysis

Variations in salivary components are closely associated with the predisposition and state of disease, the abnormal changes of salivary glycopeptidome are usually discovered as perilous singals of serious disease. Therefore, the monitoring and analyzing of salivary glycopeptidome are of even more overriding importance. In this work, a low-cost layer-by-layer assembly strategy was adopted to fabricate a hydrophilic multilayer magnetic probe (dubbed Mag-m-G6P) for salivary glycopeptidome analysis. The successful construction of multilayer structure not only guaranteed the good dispersal of probe by protecting magnetic core from itself aggregation tendency, but also endowed the probe with multiple advantages including the good hydrophilicity, uniform mesopore size and strong magnetic responsiveness, etc. As expected, with the optimized experimental conditions, the multifunctional probe showed high enrichemnt sensitivity, unbiased enrichment ability, excellent size-exclusion ability and reusability and so on in the process of standard sample analysis. At last, the Mag-m-G6P was successfully applied to salivary glycopeptidome analysis on further combination with LC-MS/MS analysis, a total of 53 endogenous glycopeptides were identified from human saliva.