Eco-friendly chitosan microspheres as a novel one-step sorbent for the rapid purification and determination of pesticides and veterinary drug multi-residues in aquatic products with HPLC-MS/MS.

A modified QuEChERS method was developed to determine multi-class pesticide and veterinary residues in aquatic products. Chitosan microspheres were conveniently synthesized and utilized as the cleanup adsorbent in the QuEChERS procedure, showcasing rapid filtration one-step pretreatment ability for the determination of drug multi-residues in aquatic products. Compared to conventional synthetic sorbents, chitosan microspheres not only have good purification performance, but also have renewable and degradable properties. This novel sorbent worked well in the simultaneous determination of 95 pesticides and veterinary drug residues in aquatic products after being combined with an improved one-step vortex oscillating cleanup method. We achieved recoveries ranging from 64.0% to 115.9% for target drugs in shrimp and fish matrix. The limits of detection and quantification were 0.5-1.0 and 1.0-2.0 µg kg-1, respectively. Notably, hydrocortisone was detected with considerable frequency and concentration in the tested samples, underscoring the necessity for stringent monitoring of this compound in aquatic products.

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.

Optimization and Validation of a Cheaper, Safer, and More Sustainable Methodology for Aflatoxins Determination in Rich-Lipidic Matrices (Pistachio Nuts) Using Deep Eutectic Solvent Extraction and UHPLC-FLD Analysis.

Aflatoxins pose a major health concern and require strict monitoring in food products. Existing methods rely on hazardous organic solvents for extraction, prompting the development of a greener alternative. This study explores deep eutectic solvents (DESs) for aflatoxin extraction from pistachios, a valuable food product prone to aflatoxin contamination. The proposed method utilizes DES extraction followed by solid-phase extraction cleanup and ultrahigh-performance liquid chromatography coupled with fluorescence detector analysis. Recovery rates ranged from 85.5 to 99.1% for pistachios spiked with 1-8 ng/g aflatoxins, in compliance with EU regulations, with coefficients of variation less than 2.94%. The method demonstrates good sensitivity with limits of detection and quantification in the range of 0.02-0.22 ng/g and 0.05-0.72 ng/g, respectively. Greenness assessment using AGREEPrep and White Analytical Chemistry metrics confirms its environmental sustainability. This approach offers a promising, safer, and more eco-friendly alternative for aflatoxin extraction from complex food matrices like pistachios.

Hydrophilic molecularly imprinted thermal-responsive polymers based sorbent for ambient ionization mass spectrometric analysis of sulfonamide antibiotics from food samples.

The thermal-responsive magnetic molecularly imprinted polymer (TrMMIP) sorbent was synthesized by surface imprinting method, and then used for magnetic solid-phase extraction (MSPE) and subsequent integrated into the ion source for elution and ionization. The shrinking-strength states change of the thermal-responsive polymer chain on TrMMIP alters the wettability of the sorbent when the working temperature crosses the lower critical solution temperature (LCST) of the polymer, and thus affects its behavior of in the extraction and clean-up process. The targeted analytes could be effectively extracted due to the high selectivity of MIPs and well dispersibility of polymer chain under the open state. Additionally, a hydrophilic polymer chain wrapped on the sorbent surface further protected target substances from co-elution during cleanup. Analytical methods for sulfonamide antibiotics (SAs) detection in complex food samples (milk, honey, fish) were developed, demonstrating potential for rapid and sensitive SAs analysis in diverse food and biological samples.

A magnetic carboxyl-functionalized covalent organic framework for the efficient enrichment of foodborne heterocyclic aromatic amines prior to UPLC-MS analysis.

Foodborne heterocyclic aromatic amines (HAAs) are potent mutagens and carcinogens, posing significant health risks. Existing enrichment methods for HAAs need better adsorption selectivity and capacity for daily exposure assessment. This study hypothesized that introducing carboxylic groups into magnetic covalent organic frameworks (m-COFs) would improve HAAs adsorption by providing additional binding sites. Hence, we prepared a novel magnetic adsorbent, termed as Fe3O4@DOPA-TpPa-(COOH)2 capable of enhancing the HAAs detection through magnetic solid-phase extraction (MSPE) coupled with UPLC-MS. This sorbent demonstrated a large specific surface area (130.7 m2/g), high magnetic responsivity (21.05 emu/g), and robust stability, with an adsorption capacity (Qm[cal]: 81.82 mg/g) driven by electrostatic, LP - π/C-H - π interactions, and hydrogen bonding. Optimal MSPE conditions provided sensitive detection with a broad linear range (5-500 ng/mL), low limits of detection (0.01-7.01 ng/g), and excellent repeatability. Application to Cantonese mooncake samples showed satisfactory recoveries (62.12%-126.86%). This method offers a more accurate tool for detecting HAAs.

Computational simulation-assisted template selection of magnetic MOFs molecularly imprinted materials applying the adsorption and detection of multiple fluoroquinolones.

This study utilized computational simulation and surface molecular imprinting technology to develop a magnetic metal-organic framework molecularly imprinted polymer (Fe3O4@ZIF-8@SMIP) capable of selectively recognizing and detecting multiple fluoroquinolones (FQs). The Fe3O4@ZIF-8@SMIP material was synthesized using the "common" template-ofloxacin, identified by computational simulation, demonstrating notable adsorption capacity (88.61-212.93 mg g-1) and rapid mass-transfer features (equilibration time: 2-3 min) for all tested FQs, consistent with Langmuir adsorption model. Subsequently, this material was employed as a magnetic solid-phase-extraction adsorbent for adsorption and detection of multiple FQs by combining with high performance liquid chromatography. The developed method exhibited good linearity for various FQs within the concentration range of 0.1-500 µg L-1, with low limit of detection (0.0605-0.1529 µg L-1) and limit of quantitation (0.2017-0.5097 µg L-1). Satisfactory recoveries (88.38-103.44%) were obtained when applied to spiked food samples, demonstrating the substantial potential of this Fe3O4@ZIF-8@SMIP material for rapid enrichment and identification for multiple FQs residues.

Hydroxyl-functionalized cationic porous organic polymers for efficient enrichment and detection of phenolic endocrine disrupting chemicals in water and snapper.

Endocrine-disrupting chemicals (EDCs) can disrupt the normal functioning of the endocrine system in organisms, leading to various health issues. Therefore, monitoring EDCs in the environment and food is of significant importance. In this study, a hydroxyl-functionalized ionic porous organic polymer (OH-IPOP) has been synthesized for the first time using 2-benzimidazolemethanol as a monomer. The OH-IPOP exhibited excellent adsorption performance towards phenolic EDCs. An efficient method for determination of phenolic EDCs (p-tert-butylphenol, bisphenol B, bisphenol A and bisphenol F) in environmental water and snapper samples was successfully established by with OH-IPOP as solid-phase extraction sorbent and determination with high-performance liquid chromatography-ultraviolet detection. The method showed good linearity (r2 > 0.998), low detection limits (0.008-0.020 ng mL-1 for lake water, 1.00-3.00 ng/g for snapper), high recovery rates (82.3-106 %), and good precision (relative standard deviation < 6.6 %), making it a highly efficient adsorbent for the enrichment of EDCs in complex sample matrices.

Dual-template magnetic molecularly imprinted polymers for selective extraction and sensitive detection of aflatoxin B1 and benzo(α)pyrene in environmental water and edible oil.

The coexistence of multiple contaminates in the environment and food is of growing concern due to their extremely hazard as a well-known class I carcinogen, like aflatoxin B1 (AFB1) and benzo(α)pyrene (BaP). AFB1 and BaP are susceptible to coexistence in environmental water and edible oil, posing a significant potential risk to environmental monitoring and food safety. The remaining challenges in detecting multiple contaminates include unsatisfied sensitivity, insufficient targets selectivity, and interferences in complex matrices. Here, we developed dual-template magnetic molecularly imprinted polymers (DMMIPs) for selective extraction of dual targets in complex matrices from the environment and food. The DMMIPs were fabricated by surface imprinting with vinyl-functionalized Fe3O4 as carrier, 5,7-dimethoxycoumarin and pyrene as dummy templates, and methacrylamide as functional monomer. The DMMIPs showed excellent adsorption ability (12.73-15.80 mg/g), imprinting factors (2.01-2.58), and reusability of three adsorption-desorption cycles for AFB1 and BaP. The adsorption mechanism including hydrogen bond, electrostatic interaction and van der Waals force was confirmed by physical characterization and DFT calculation. Applying DMMIPs in magnetic solid phase extraction (MSPE) followed by high-performance liquid chromatography (HPLC) analysis enabled detection limits of 0.134 µg/L for AFB1 and 0.107 µg/L for BaP. Recovery rates for water and edible oil samples were recorded as 86.2%-110.3% with RSDs of 4.1%-11.9%. This approach demonstrates potential for simultaneous identification and extraction of multiple contaminants in environmental and food.

Direct extraction of ten estrogens from milk samples with DVB/NVP-modified magnetic solid-phase extraction adsorbent followed by pre-column derivatization-UHPLC-MS/MS.

Estrogens and their analogues can cause harm to human health through the food chain. Ten estrogens in different milk samples were directly extracted by amphiphilic divinylbenzene/N-vinyl-2-pyrrolidone (DVB/NVP)-Fe3O4@SiO2-based magnetic solid-phase extraction (MSPE) followed by pre-column derivatization and ultra-high performance liquid chromatography tandem mass-spectrometry (UHPLC-MS/MS) detection. Under the optimal conditions, the limits of detection for ten analytes were in the range of 0.05-0.38 ng mL-1 in whole liquid milk matrix and 0.04-3.00 ng g-1 in milk powder matrix. The intra-/inter-day accuracy ranged in 83.4-113.8%, with RSDs in 2.5-15.0%. A total of 15 brands of liquid milk and milk powder samples were analyzed, and only estradiol was detected in three brands of boxed liquid milk within safe range. The proposed sample pretreatment eliminated the common protein precipitation process, improved the sample throughput, and has the potential for routine testing of estrogens and their analogues in market-sale milk samples.

Determination of tetrodotoxin in human plasma and urine using online MCX SPE column cleanup coupled with liquid chromatography-tandem mass spectrometry.

An efficient technique for quantitative analysis of tetrodotoxin (TTX) in human plasma and urine has been developed, which combines liquid chromatography-tandem mass spectrometry (LC-MS/MS) with online MCX solid phase extraction (SPE) cleanup. Sample preparation, including extraction with acetonitrile containing 0.5 % acetate acid, centrifugation, and filtration, was followed by online SPE cleanup. The whole run-time was less than 15 min, including online cleanup, chromatographic separation, and re-equilibration of the online SPE - LC-MS/MS system. The parameters of sample extraction, purification, separation, and detection were optimized. The matrix-matched internal standard calibration standard curves with linear regression coefficients larger than 0.9990 were established for quantification. The LOD and LOQ for this approach were determined to be 0.1 ng/mL and 0.3 ng/mL, respectively. The recoveries for varied concentrations of TTX in human plasma and urine were 84.9-104.2 % and 89.2-109.6 %, respectively. The matrix effects of TTX in human plasma and urine matrices were 85.5 % and 74.3 %, respectively, and both the inter- and intra-day precision values were less than 9.5 %. This analytical method was successfully employed for detecting TTX in biological samples from a poisoned patient who accidentally ingested the nassarius glans.

Mathematical model of ion chronogram from in-tube solid-phase microextraction device coupled with mass spectrometry and optimization framework.

A mathematical description and experimental outputs exhibited that an ion chronogram from an in-tube solid-phase microextraction (SPME) device linked with mass spectrometry (in-tube-SPME-MS) generally appears as a right-skew unimodal signal with a heavy right tail. Analogous to liquid chromatography coupled with mass spectrometry (LC-MS), in-tube-SPME-MS can utilize the area under its produced ion chronogram for regression analysis and has been shown to be a potential approach for fast quantification of analyte. Different level of unimodity of signal in the ion chronogram could positively or negatively affect the choice of the area used for quantification and finally impact on analysis sensitivity and time efficiency of in-tube-SPME-MS. In the paper, we showed that different in-tube SPME design choices and elution experimental setups produce ion chronograms with controllable varying unimodal peak shape patterns. An improved mathematical model was built based on the plate theory of chromatography and the Van Deemter equation to quantitatively describe the elution process from in-tube-SPME device. A computer simulation was implemented to predict ion chronograms and the results were compared with experimental ion chronograms to show the effectiveness of the model. An optimization framework was further presented based on the model to identify optimal device designs (length and diameter of device) and experimental parameters (flow rate) to track targeted ion chronograms with "desired" peak shape patterns. Empirical elution experiments with the in-tube SPME devices adopting optimized geometric parameters and optimal experimental setups confirmed the consistency between the experimental ion chronograms and the numerical simulations to a certain level.

Fabrication of fluorinated magnetic microporous organic network for selective and efficient extraction of benzoylurea insecticides in tea beverages.

In this work, a novel fluorinated magnetic microporous organic network (Fe3O4@FMON) was exquisitely designed and synthesized for highly efficient and selective magnetic solid phase extraction (MSPE) of fluorinated benzoylurea insecticides (BUs) from complex tea beverage samples. The Fe3O4@FMON exhibited good extraction for BUs via the pre-designed hydrophobic, π-π stacking, hydrogen bonding and specific FF interactions. A sensitive Fe3O4@FMON-based MSPE-HPLC-UV method with wide linear range (0.10-1000 µg L-1, R2 ≥ 0.996), low limits of detection (0.01-0.02 µg L-1), and large enrichment factors (85.6-98.0) for BUs from tea beverage samples was developed. By decorating F elements within MON's networks, the Fe3O4@FMON characterized good hydrophobicity and chemical stability, which could be reused at least 8 times without decrease of recoveries. This work demonstrated the great prospects of Fe3O4@FMON for enriching trace BUs from complex substrates and triggered the potential of FMON for sample pretreatment of fluorinated analytes.

Synthesis of green magnetic molecularly imprinted polymers for selective extraction of rifaximin in milk samples.

In this study, a new analytical method was developed using magnetic molecularly imprinted polymers (MMIPs) by employing eco-friendly supramolecular ternary deep eutectic solvents to synthesize these MMIPs for selective extraction of rifaximin. The characterization analysis and adsorption affinity investigation were conducted. The results showed fast adsorption (15 min) with high adsorption capacity (43.20 mg g-1) and selectivity for rifaximin. Various extraction parameters were optimized, achieving recoveries ranging from 86.67% to 99.47% in spiked milk samples using high-performance liquid chromatography (HPLC). The detection and quantification limits were 0.01 mg L-1 and 0.03 mg L-1, respectively. The method exhibited low RSDs (<4.70%) and excellent selectivity, with MMIPs reusable up to seven times with only a 10% performance loss. This study proposes a convenient and reliable method for trace-level rifaximin extraction from milk using eco-friendly MMIPs.

Extraction and preconcentration of lead (II) in various water and food samples by orbital shaker-assisted magnetic solid phase extraction method using a new magnetic poly linoleic acid-polystyrene-PDMS block copolymer.

The aim of this study was to develop a practical orbital shaker-assisted magnetic solid phase extraction (OSA-MSPE) method for the determination of lead by FAAS. A new magnetic poly linoleic acid-polystyrene-polydimethylsiloxane (PSt-PLina-PDMS) hydrophobic graft copolymer was synthesized and characterized by NMR, FT-IR, SEM-EDX, DSC, TGA, BET and used as adsorbent for the extraction of Pb (II). This adsorbent can be used at least 50 times without any decrease of its adsorption properties for the adsorption and elution of analyte ions. Several analytical parameters including pH, adsorbent amount, sample volume, shaking time, etc. were optimized. Multivariate optimization was used for the investigation of different parameters. The linear range at optimum operating condition was 1.7-84 µg L-1. The limit of detection (LOD) and limit of quantification (LOQ) were 0.5 µg L-1, 1.7 µg L-1, respectively. Intraday and interday relative standard deviation (RSD %), enhancement factor (EF) and adsorbent capacity were found as 1.9%, 3.3%, 166.7, 50 mg g-1, respectively. OSA-MSPE method was tested with certified reference materials including LGC-6010 (Hard Drinking Water), NCS ZC73032 Celery and CS-M-3 Control Sample Microelements in Mushroom Powder for the accuracy. Experimental results for lead were confirmed with certified values. Present method was successfully applied to various liquid and solid food samples. The OSA-MSPE method has some important features such as selective, sensitive, low LOD, LOQ and RSD, pre-concentration factor (PF) and high enhancement factor (EF). High tolerance limits against matrix ions were achieved.

A smartphone-enabled visual platform for detecting aflatoxins in peanut oil using colorimetric analysis coupled with magnetic imprinted solid-phase extraction.

The study aimed to develop a rapid and sensitive colorimetric platform based on the Emerson reaction to visualize and determine total aflatoxins (AFs) in peanut oil. This method offers the advantage of fast screening for AFs (AFB1, AFB2, AFG1, and AFG2), eliminating the need for specific antibodies. The proposed approach combined colorimetric detection with magnetic dummy imprinted solid-phase extraction and purification, enhancing sensitivity and selectivity. The oxidizer aided the colorless AFs in reacting with 4-aminoantipyrine, producing green condensates. Thus, a dual-mode approach was developed for AFs detection, employing both UV-vis colorimetric and smartphone-based colorimetry. Both methods showed a good linear relationship with the concentration of AFs. Notably, the smartphone-based method demonstrated a detection range of 0.5-57 µg/kg, with a detection limit as low as 0.21 µg/kg. The suggested colorimetric methods present a promising potential for onsite detection and fast screening of AFs in actual samples.

Fabrication of a magnetic functionalized chitosan hydrogel for effective extraction of aflatoxins from cereals.

A magnetic adsorbent was synthesized by coupling magnetic nanoparticles, UiO-66-NH2 and 1-butyl-trimethylimidazole bromide ([BMIM][Br]) to chitosan (CS)-based composite conveniently. A series of modern characterizations were employed to assess its properties. The results showed that UiO-66-NH2 was uniformly distributed within the composite via in-situ growth, which can enhance the porosity obviously. The introduction of various ligands enables the composite to exhibit excellent extraction performance for four aflatoxins (AFs) through multiple interactions. The adsorption mechanism was elucidated and the main factors affecting extraction efficiency were evaluated. Under optimal conditions, the limits of detection (LODs) ranged from 0.08 to 0.56 µg/kg. The established method was successfully utilized to determine AFs from cereal samples (rice, glutinous rice, wheat, soybean, paddy, and corn) with satisfactory recovery of 77% âˆ¼ 119% with relative standard deviations (RSDs) of 1.0% âˆ¼ 11.7% (n = 5). The adsorbent demonstrated sufficient robustness for repeated use at least six times without obvious damage of extraction property.

Development of a NiFe2O4 covalent organic framework based magnetic solid-phase extraction approach for specific capture of quinolones in animal innards prior to UHPLC-Q-Orbitrap HRMS detection.

This study aimed to present a selective and effective method for analyzing quinolones (QNs) in food matrix. Herein, a NiFe2O4-based magnetic sodium disulfonate covalent organic framework (NiFe2O4/COF) was prepared using a simple solvent-free grinding method, and was adopted as a selective adsorbent for magnetic solid phase extraction of QNs. Coupled with UHPLC-Q-Orbitrap HRMS, an efficient method for simultaneous detection of 18 kinds of QNs was established. The method exhibited good linearity (0.01-100 ng g-1), high sensitivity (LODs ranging from 0.0011 to 0.0652 ng g-1) and precision (RSDs below 9.5%). Successful extraction of QNs from liver and kidney samples was achieved with satisfactory recoveries ranging from 82.2% to 108.4%. The abundant sulfonate functional groups on NiFe2O4/COF facilitated strong affinity to QNs through electrostatic and hydrogen bonding interactions. The proposed method provides a new idea for the extraction of contaminants with target selectivity.

Two-dimensional hydrophilic imprinted resin-graphene oxide composite for selective extraction and rapid determination of gibberellin traces in licorice samples.

This study presents novel methodologies and materials for selectively and sensitively determining gibberellin traces in licorice to address food safety concerns. A novel hydrophilic imprinted resin-graphene oxide composite (HMIR-GO) was developed with fast mass transfer, high adsorption capacity, and exceptional aqueous recognition performance for gibberellin. Leveraging the advantages of molecular imprinting, hydrophilic resin synthesis, and rapid mass transfer characteristics of GO, HMIR-GO was employed as an adsorbent, showing resistance to matrix interference. Coupled with HPLC, a rapid and selective method for determining gibberellin was established. Under optimal conditions, the method exhibited a wide linear range (0.02-5.00 µg g-1, r = 0.9999), low detection limits (3.3 ng g-1), and satisfactory recoveries (92.0-98.4%), enabling the accurate and rapid detection of gibberellin in licorice. This study introduces a pioneering strategy for the selective extraction and determination of trace gibberellin levels, offering insights for similar applications in functional foods.

Magnetic solid-phase extraction of tetracyclines from milk using metal-organic framework MIL-101(Cr)-NH2 functionalised hydrophilic magnetic nanoparticles.

Novel metal-organic framework MIL-101(Cr)-NH2 functionalised hydrophilic polydopamine-modified Fe3O4 magnetic nanoparticles (Fe3O4@PDA@MIL-101(Cr)-NH2) were synthesised and used as magnetic solid-phase extraction (MSPE) adsorbents for extracting tetracyclines (TCs) from milk samples. The integrated Fe3O4@PDA@MIL-101(Cr)-NH2 exhibited convenient magnetic separation and exceptional multi-target binding capabilities. Furthermore, the PDA coating significantly enhanced the hydrophilicity and extraction efficiency of the material, thereby facilitating the extraction of trace TCs. Various factors affecting MSPE, such as adsorbent dosage, extraction time, pH value, and desorption conditions, were optimised. The developed MSPE method coupled with high-performance liquid chromatography demonstrated good linearity (R2 ≥ 0.9989), acceptable accuracy (82.2%-106.1%), good repeatability (intra-day precision of 0.8%-4.7% and inter-day precision of 1.1%-4.5%), low limits of detection (2.18-6.25 µg L-1), and low limits of quantification (6.54-18.75 µg L-1) in TCs detection. The approach was successfully used for the quantification of trace TCs in real milk samples.

Molecularly imprinted resin modified with ionic liquid for dispersive filter extraction and determination of perfluoroalkyl acids in eggs.

Perfluoroalkyl acids (PFAAs) are emerging pollutants that endangers food safety. Developing methods for the selective determination of trace PFAAs in complex samples remains challenging. Herein, an ionic liquid modified porous imprinted phenolic resin-dispersive filter extraction-liquid chromatography-tandem mass spectrometry (IL-PIPR-DFE-LC-MS/MS) method was developed for the determination of perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) in eggs. The new IL-PIPR adsorbent was prepared at room temperature, which avoids the disorder and instability of the template at high temperatures. The imprinting factor of IL-PIPR for PFOA and PFOS exceeded 7.3. DFE, combined with IL-PIPR (15 mg), was used to extract PFOA and PFOS from eggs within 15 min. The established method exhibits low limits of detection (0.01-0.02 ng/g) and high recoveries (84.7%-104.7%), which surpass those of previously reported methods. This work offers a new approach to explore advanced imprinted adsorbents for PFAAs, efficient sample pretreatment technique, and analytical method for pollutants in foods.