Combustion fabrication of magnetic porous carbon as a novel magnetic solid-phase extraction adsorbent for the determination of non-steroidal anti-inflammatory drugs

β-Cyclodextrin based magnetic hyper-crosslinked polymer: A recyclable adsorbent for effective preconcentration of triazine herbicides in complex sample matrices

High efficiency enrichment and trace analysis of triazine herbicide residues are crucial for ensuring environmental and food safety. Herein, a series of magnetic hyper-crosslinked polymers (CD-gs-MHCPs) were synthesized with different crosslinkers, which might possess different pore structure and surface area, so they might dispay variable adsorption performance. CD-gs-MHCP2 with dichloroxylene as crosslinker delivered superior adsorption ability for triazine herbicides (THs). The synergistic effect of hydrogen bonds, hydrophobic interaction, π-π stacking interaction and pore adsorption were proved to be the main adsorption mechanism. Combined CD-gs-MHCP2 based magnetic solid-phase extraction (MSPE) with high-performance liquid chromatography, the quantitative analysis of THs in river water and vegetable samples (zucchini, pakchoi) was achieved. Under the optimal conditions, the enrichment factors for three different samples ranged from 94 to 244 and low detection limit (S/N = 3) of the four THs were obtained from 0.05 to 0.15 ng mL-1 for river water and 0.31-3.10 ng g-1 for vegetable samples. The method recoveries were in the range of 86.2 %-120 % with relative standard deviations lower than 7.4 %. This work not only offers a new strategy for fabrication β-CD-based HCPs, but also provided a practical and effective method for efficient isolation and sensitive detection of trace THs residues in complex samples.

Extraction of methamphetamine and pseudoephedrine by modified graphene oxide solid phase extraction method coupled to HPLC-UV in urine sample

Methamphetamine, pseudoephedrine, and related drugs are among the first drugs used for the stimulation of the central nervous system. In this study, two adsorbents based on graphene oxide (GO) were synthesized and used for the analysis of methamphetamine and pseudoephedrine. The prepared nano-adsorbents based on GO in this study were coated by polyaniline (PANI) and Fe3O4/C-nanodot/GO (magnetic adsorbent). The average size of nanoparticles (GO/PANI) was 18.43 nm. The specific surface area and pore size diameter of Fe3O4/C-nanodot/GO were 22.71 m2 g- 1 and 15.23 nm, respectively. Experimental variables affecting the extraction efficiency of the analytes such as pH of the sample solution, amount of adsorbent, extraction time, and type of eluents were investigated and optimized by response surface methodology. Under optimum conditions, GO/PANI and Fe3O4/C-nanodot/GO were considered appropriate solid phase extraction adsorbents for HPLC-based analyses of the studied drugs in human urine samples. However, GO/Fe3O4 nano adsorbent (Fe3O4/C-nanodot/GO) showed superior working condition than GO/PANI. The validated proposed analytical methods can be used for the quantitative determination of methamphetamine and pseudoephedrine in actual samples.

Fast and efficient extraction and determination of nonsteroidal anti-inflammatory drugs using poly(8-hydroxyquinoline)-coated magnetic graphene oxide nanocomposite prior to capillary electrophoresis analysis in wastewater, breast milk, and urine samples

In this study, magnetic graphene oxide coated with poly(8-hydroxyquinoline) was successfully synthesized, characterized, and utilized as a novel sorbent for the ultrasonic-assisted dispersive magnetic solid-phase extraction of naproxen and ibuprofen. These analytes served as representative analytes for two nonsteroidal anti-inflammatory drugs in various real samples. Characterization techniques, such as IR, X-ray powder diffraction, field emission scanning electron microscopy, energy-dispersive X-ray-mapping, and Brunauer-Emmett-Teller (BET), were used to confirm the correctness synthesis and preparation of the nanocomposites. Effective parameters on the extraction efficiency were investigated to maximize the analytical performance of the developed method. The dynamic range (1-1000 µg L-1), coefficients of determination (R2 ≥ 0.997), the limits of detection (0.3-1.0 µg L-1), and limit of quantification (1.0-3.0 µg L-1), intra-day and inter-day precisions (3.5%-7.2%) were achieved. The method validation results showed extraction recovery ranging from 80.4% to 96.0% and preconcentration factors ranging from 137 to 140.

Natural deep eutectic solvent-functionalized mesoporous graphitic carbon nitride-reinforced electrospun nanofiber: a promising sorbent in miniaturized on-chip thin film micro-solid-phase extraction prior to liquid chromatography-tandem mass spectrometry for measuring NSAIDs in saliva

To meet the needs of developing efficient extractive materials alongside the evolution of miniaturized sorbent-based sample preparation techniques, a mesoporous structure of g-C3N4 doped with sulfur as a heteroatom was achieved utilizing a bubble template approach while avoiding the severe conditions of other methods. In an effort to increase the number of adsorption sites, the resultant exfoliated structure was then modified with thymol-coumarin NADES as a natural sorbent modifier, followed by introduction into a nylon 6 polymer via an electrospinning process. X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, field-emission scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), and Brunauer-Emmett-Teller (BET) surface area analysis validated S-doped g-C3N4 and composite production. The prepared electrospun fiber nanocomposite, entailing satisfactory processability, was then successfully utilized as a sorbent in on-chip thin film micro-solid-phase extraction of non-steroidal anti-inflammatory drugs (NSAIDs) from saliva samples prior to liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis. Utilizing a chip device, a thin film μ-SPE coupled with LC-MS/MS analysis yielded promising outcomes with reduced sample solution and organic solvents while extending lifetime of a thin film sorbent. The DES-modified S-doped g-C3N4 amount in electrospun was optimized, along with adsorption and desorption variables. Under optimal conditions, selected NSAIDs were found to have a linear range of 0.05-100.0 ng mL-1 with an R2 ≥ 0.997. The detection limits were ranged between 0.02 and 0.2 ng mL-1. The intra-day and inter-day precisions obtained were less than 6.0%. Relative recoveries were between 93.3 and 111.4%.

Modification of cellulose substrate by in situ synthesis of metal-organic framework-5 for thin film microextraction of some non-steroidal anti-inflammatory drugs and their measurement by high-performance liquid chromatography-ultraviolet detector

This work, reports the successful preparation a thin film by a simple and inexpensive process for quantification of a model analytes in the urine sample using HPLC-UV. To this end, cellulose paper was employed as a substrate for the in-situ synthesis of MOF-5, to increase the resistance of the prepared film. The prepared film can be reused 26 times with no reduction in its performance. The thin film prepared by MOF-5 modified cellulose substrate was utilized in thin film microextraction (TFME) method for the extraction and preconcentration of naproxen, aspirin, tolmetin, and celecoxib. Under optimal conditions, the linear dynamic range of the target analytes was 2-500 µg L-1 with correlation coefficients (R2) ranging from 0.9961 to 0.9990. Also, the limits of detection (LODs), the limits of quantification (LOQs) and relative standard deviation (RSD%) of the proposed method for selected analytes ranged between 0.57 and 0.77 µg L-1, 1.7 to 2.3 and 3.5 % to 6.2 %, respectively. Moreover, relative recoveries varied from of 94 % to 108 %, indicating the absence of matrices effect in the proposed method. Eventually, the TFME was successfully used for the extraction of selected analytes from urine samples.

Green and efficient magnetic micro-solid phase extraction utilizing tea waste impregnated with magnetic nanoparticles for the analysis of ibuprofen in water samples by using UV-vis spectrophotometry

A green method based on magnetic micro-solid phase extraction (MNP-TW-μ-SPE) of tea waste impregnated with magnetic nanoparticles (MNP-TW) was developed for the extraction of ibuprofen (IBP) in water samples prior to UV-Vis spectrophotometric analysis. Experimenting parameters that affect the extraction efficiency of IBP, such as pH of the sample solution, sorbent dosage, extraction time, ionic strength, volume of the sample, type of desorption solvent, desorption time, and desorption volume, were studied and optimized in detail. The characterization studies for the MNP-TW were carried out by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction spectrometry (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), Brunauer-Emmett-Teller (BET) analysis, a vibrating sample magnetometer (VSM), and thermogravimetric analysis (TGA). Under the optimum conditions, the linearity ranges from 30 to 700 μg L-1 for IBP, with determination coefficients (R2) of 0.9983. The limit of detection (LOD) and limit of quantification (LOQ) were 9.40 μg L-1 and 28.50 μg L-1, respectively. The method also demonstrated good precision in reproducibility (RSD ≤ 1.53%), repeatability (RSD ≤ 1.48%), and recovery (86-115%). This method represents the advantages of low solvent consumption, flexibility, and better sensitivity compared to other studies employing spectrophotometric analysis. The usage of tea waste in the extraction process presents many advantages, as it is biodegradable, versatile, and contributes to an intelligent and sustainable economic strategy projected toward a circular economy approach.

Boosted simultaneous removal of chlortetracycline and Cu (II) by Litchi Leaves Biochar: Influence of pH, ionic strength, and background electrolyte ions

The coexistence of heavy metals and antibiotics in the environment always results in greater toxicity compared to the individual precursors. Therefore, efficient and economic technology for the simultaneous removal of antibiotics and heavy metals is essential. Herein, litchi leaves biochar carbonized at 550 °C (L550) demonstrated high efficiency in co-removal of CTC (1838.1 mmol/kg) and Cu (II) (1212.9 mmol/kg) within wide range of pH (pH 4-7). Ionic strength obviously enhanced the Cu (II) removal but showed no significant effect on CTC removal. Although Al3+ and HPO42- decreased the adsorption capacities of CTC and Cu (II) on L550, the coexistence of Na+, K+, Mg2+, Cl-, NO3-, CO32- and SO42- showed a negligible effect on the simultaneous removal of CTC and Cu (II). Moreover, the adsorption capacities of CTC and Cu (II) on L550 were excellent in the river water, tap water, and lake water. In addition to electrostatic interactions, ion exchange governed Cu (II) adsorption, while surface complexation played a key role in CTC adsorption on L550. Our results demonstrated that litchi leaves biochar could be a promising adsorbent for remediating multi-contaminated environments.

Deep eutectic solvent-based ferrofluid for vortex-assisted liquid-liquid microextraction of nonsteroidal anti-inflammatory drugs from environmental waters

A novel ferrofluid of Fe3O4 nanoparticles and a deep eutectic solvent (DES) composed of menthol and pentanoic acid was introduced as a green microextraction medium. The ferrofluid was successfully used as an extractant for vortex-assisted liquid-liquid microextraction (VALLME) of nonsteroidal anti-inflammatory drugs (NSAIDs) in environmental waters prior to their determination by HPLC-DAD. Once the ferrofluid was dispersed in the sample by vortex agitation, phase separation could be easily achieved by placing a neodymium magnet next to the tube, which eliminated the centrifugation step and simplified the operational procedure. As a result, the sample pretreatment took only ≈2 min. The experimental parameters, including pH, nanoparticle amount, ferrofluid volume, vortex time, salt amount, and disruptive solvent type and its volume, were optimized stepwise. The method showed linear behavior for all NSAIDs from 5 to 100 μg/L, with limit of detection values and enrichment factors in the ranges of 1.68-2.05 μg/L and 38.9-50.6, respectively. Intra- and Inter-day accuracies obtained from the analysis of spiked river, lake, and tap water samples at low and high-quality control levels (20 and 80 μg/L) ranged from 90.3% to 108.0%, with relative standard deviations less than <12.3%. The results of this study demonstrate that the use of DES-based ferrofluid in VALLME can be considered a simple, environmentally friendly, and reliable alternative for the determination of NSAIDs in environmental waters.

Non-steroidal anti-inflammatory drugs (NSAIDs) in the environment: Updates on pretreatment and determination methods

Non-steroidal anti-inflammatory drugs (NSAIDs) are widely used in human and animal health care to reduce persistent inflammation, pain and fever because of their anti-inflammatory, analgesic and antipyretic effects. However, the improper discharge and disposal make it becomes a major contaminant in the environment, which poses a big threat to the ecosystem. For this reason, accurate, sensitive, effective, green, and economic techniques are urgently required and have been rapidly developed in recent years. This review summarizes the advancement of sample preparation technologies for NSAIDs involving solid-phase extraction, solid-phase microextraction, liquid-phase microextraction, QuEChERS, and matrix solid-phase dispersion. Meanwhile, we overview and compare analytical technologies for NSAIDs, including liquid chromatography-based methods, gas chromatography-based methods, capillary electrophoresis, and sensors, particularly the development of liquid chromatography-based methods. Furthermore, we focus on their progress and conduct a comparison between their advantages and disadvantages.

Ionic liquid-modified UiO-66-NH2 as sorbent of dispersive solid-phase extraction for rapid adsorption and enrichment of benzoylurea insecticides

Ionic liquid (IL)-modified UiO-66-NH2 composite was prepared and used as sorbent of dispersed solid-phase extraction (dSPE) for extracting trace benzoylurea insecticides (BUs) from complex environmental matrices. The IL in framework endowed the prepared material had electropositive characteristics, which can produce interaction with electron rich guest molecules, such as BUs. The high thermal and chemical stability of UiO-66-NH2/IL enabled it to be reused for 16 times without significant reduction in adsorption performance. Due to the multiple forces including π-π, hydrogen bonding, and fluorine-fluorine interaction, UiO-66-NH2/IL showed good adsorption performance, short adsorption time (20 s) and rapid desorption ability (60 s) for BUs. Under the optimal conditions, the method exhibited wide linear range (0.02-500 ng mL-1) with correlation coefficient (R2) not worse than 0.9928, high enrichment factor (252-300), and low detection limit (0.005-0.4 ng mL-1). The dispersed solid phase extraction coupling with high-performance liquid chromatography-diode array detector (dSPE-HPLC-DAD) was successfully used to detection of BUs in real environmental samples and satisfactory recoveries were obtained (80.5%±2.4-118%±3.2). The results indicated that UiO-66-NH2/IL composite can be a potential sorbent for the preconcentration of trace insecticides in environmental samples.

Selective extraction of apixaban from plasma by dispersive solid-phase microextraction using magnetic metal organic framework combined with molecularly imprinted polymer nanocomposite

This research aims to synthesize a specific and efficient sorbent to use in the extraction of apixaban from human plasma samples and its determination by high-performance liquid chromatography-tandem mass spectrometry. High specific surface area of metal-organic framework, magnetic property of iron oxide nanoparticles, selectively of molecular imprinted polymer toward the analyte, and the combination of dispersive solid-phase extraction method with a sensitive analysis system provided an efficient analytical method. In this study, first, a molecularly imprinted polymer combined with magnetic metal organic framework nanocomposite was prepared and then characterized using different techniques. Then the sorbent particles were used for selective extraction of the analyte from plasma samples. The efficiency of the method was improved by optimizing effective parameters. According to the validation results, wide linear range (1.02-200 ng mL-1 ), acceptable coefficient of determination (0.9938), low limit of detection (0.32 ng mL-1 ) and limit of quantification (1.02 ng mL-1 ), high extraction recovery (78%), and good precision (relative standard deviations ≤ 2.9% for intra- (n = 6) and interday (n = 6) precisions) were obtainable using the proposed method. These outcomes showed the high potential of the proposed method for screening apixaban in the human plasma samples.

Polyester fabric-based nano copper-polyhedral oligomeric silsesquioxanes sorbent for thin film extraction of non-steroidal anti-inflammatory drugs

In this study, in-situ preparation of copper nanoparticles under sonoheating conditions followed by coating on commercial polyester fabric is reported. Through the self-assembly interaction of thiol groups and copper nanoparticles, the modified polyhedral oligomeric silsesquioxanes (POSS) was deposited on the fabric's surface. In the next step, radical thiol-ene click reactions were implemented to create more layers of POSSs. Subsequently, the modified fabric was applied for sorptive thin film extraction of non-steroidal anti-inflammatory drugs (NSAIDs) including naproxen, ibuprofen, diclofenac, and mefenamic acid from urine samples, followed by high-performance liquid chromatography equipped with a UV detector. The morphology of the prepared fabric phase was characterized by scanning electron microscopy, water angle contact, energy dispersive spectrometry mapping, analysis of nitrogen adsorption-desorption isotherms, and attenuated total reflectance Fourier transform infrared spectroscopy. The significant extraction parameters, including the acidity of the sample solution, desorption solvent and its volume, extraction time, and desorption time, were investigated using the one-variable-at-a-time approach. Under the optimal condition, NSAIDs' detection limit was 0.3-1 ng mL^-1 with a wide linear range of 1-1000 ng mL^-1. The recovery values were between 94.0% and 110.0%, with relative standard deviations of less than 6.3%. The prepared fabric phase exhibited acceptable repeatability, stability, and sorption property toward NSAIDs in urine samples.

Synthesis of molecularly imprinted polymer as a nanosorbent for dispersive magnetic micro solid-phase extraction and determination of valsartan in biological samples by UV-Vis Spectrophotometry: Isotherm, kinetics, and thermodynamic studies

A magnetic molecularly imprinted polymer (MIP) was synthesized by precipitation polymerization utilizing Fe₃O₄@SiO₂-MPS as a magnetic core, itaconic acid as a functional monomer, azobisisobutyronitrile as an initiator, and ethylene glycol dimethacrylate as a cross linker. It was then applied as a nanosorbent for dispersive magnetic micro solid phase extraction (DM-µ-SPE) and determination of valsartan in biological fluids. The morphology and structure of magnetic MIP were characterized by Fourier-transform infrared spectroscopy, Field Emission Scanning electron microscopy, Vibrating sample magnetometer, Energy dispersive x-ray analysis, and Thermogravimetric analysis. The influence of operation conditions on sorption, such as pH (4-10), contact time (10-25 min), initial concentration (1-30 mg L^-1), and temperature (25-40 °C) was investigated. After the extraction step, the valsartan concentration was determined by UV-Vis spectrophotometer at 253 nm. The isotherm and kinetic of valsartan sorption were best fitted by the Langmuir model (R² = 0.987) and the Pseudo second-order kinetic model (R² = 0.971), respectively. The maximum monolayer sorption capacity for magnetic MIP was obtained to be 4.56 mg g^-1. The analytical approach demonstrated favorable figures of merit, with a linear dynamic range of 10-100 µg L^-1, a low detection limit of 0.56 µg L^-1, and an acceptable preconcentration factor of 5 acquired in optimum conditions. The recoveries of the suggested technique at three spiked levels of analysis were in the range of 101 %-102 %. Valsartan was extracted from various real samples (urine and human blood plasma samples) utilizing the proposed magnetic nanosorbent, and the results exhibited that magnetic MIP was favorable for extraction and measurement of trace amounts of valsartan in biological samples.

Sensitive determination of bisphenols in environmental samples by magnetic porous carbon solid-phase extraction combined with capillary electrophoresis

Bisphenol compounds exist widely in the environment and pose potential hazards to the environment and human health, which has aroused widespread concern. Therefore, there is an urgent need for an efficient and sensitive analytical method to enrich and determine trace bisphenols in environmental samples. In this work, magnetic porous carbon (MPC) was synthesized by one-step pyrolysis combined with a solvothermal method for magnetic solid-phase extraction of bisphenols. The structural properties of MPC were characterized by field emission scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, and saturation magnetization analysis. Its adsorption properties were evaluated by adsorption kinetics and adsorption isotherm studies. By optimizing the magnetic solid-phase extraction and capillary electrophoresis separation conditions, a capillary electrophoresis separation and detection method for four bisphenols was successfully constructed. The results showed that the detection limits of the proposed method for the four bisphenols were 0.71-1.65 ng/mL, the intra-day and inter-day precisions were 2.27-4.03% and 2.93-4.42%, respectively, and the recoveries were 87.68%-108.0%. In addition, the MPC could be easily recycled and utilized, and even if the magnetic solid-phase extraction was repeated 5 times, the extraction efficiency could still be kept above 75%.

Vortex-assisted supramolecular solvent dispersive liquid–liquid microextraction of ketoprofen and naproxen from environmental water before chromatographic analysis: response surface methodology optimisation

A microextraction procedure that is rapid and simple to extract and preconcentrate ketoprofen and naproxen is proposed. An environmentally friendly supramolecular solvent was applied as an extraction solvent and proved to be efficient in the extraction of ketoprofen and naproxen from environmental water. The design of experiment approach was used to screen, optimize significant parameters, and determine optimum experimental conditions. Under optimized experimental conditions, the vortex-assisted supramolecular solvent dispersive liquid–liquid microextraction provided a good linearity (0.57–700 µg L−1), low limits of detection (0.17–0.24 µg L−1) and extraction reproducibility below 9%. The high percentage relative recoveries (93.6–101.4%) indicated that the method is not affected by matrix. The practical applicability of the method was assessed by analysing ketoprofen and naproxen in river water and effluent wastewater samples. Both analytes were found in effluent wastewater.

Rapid Determination of Non-Steroidal Anti-Inflammatory Drugs in Urine Samples after In-Matrix Derivatization and Fabric Phase Sorptive Extraction-Gas Chromatography-Mass Spectrometry Analysis

Fabric phase sorptive extraction (FPSE) has become a popular sorptive-based microextraction technique for the rapid analysis of a wide variety of analytes in complex matrices. The present study describes a simple and green analytical protocol based on in-matrix methyl chloroformate (MCF) derivatization of non-steroidal anti-inflammatory (NSAID) drugs in urine samples followed by FPSE and gas chromatography-mass spectrometry (GC-MS) analysis. Use of MCF as derivatizing reagent saves substantial amounts of time, reagent and energy, and can be directly performed in aqueous samples without any sample pre-treatment. The derivatized analytes were extracted using sol−gel Carbowax 20M coated FPSE membrane and eluted in 0.5 mL of MeOH for GC-MS analysis. A chemometric design of experiment-based approach was utilized comprising a Placket−Burman design (PBD) and central composite design (CCD) for screening and optimization of significant variables of derivatization and FPSE protocol, respectively. Under optimized conditions, the proposed FPSE-GC-MS method exhibited good linearity in the range of 0.1−10 µg mL−1 with coefficients of determination (R2) in the range of 0.998−0.999. The intra-day and inter-day precisions for the proposed method were lower than <7% and <10%, respectively. The developed method has been successfully applied to the determination of NSAIDs in urine samples of patients under their medication. Finally, the green character of the proposed method was evaluated using ComplexGAPI tool. The proposed method will pave the way for simper analysis of polar drugs by FPSE-GC-MS.

MIL-101(Fe)@TiO2 nanotube composite material is used for the solid phase extraction of non-steroidal anti-inflammatory drugs under the synergy of multiple interactions

Increasing the adsorption sites and effective interactions between sorbents and the targets can improve the solid-phase extraction (SPE) efficiency. Herein, based on the advantages of MOFs and TiO₂ nanotubes (TiO₂ NTs), an MIL-101(Fe)@TiO₂ NT composite was prepared and applied to extract non-steroidal anti-inflammatory drugs (NSAIDs) from water samples coupled with high performance liquid chromatography (HPLC). Through characterization, it was established that MIL-101(Fe) was effectively composited on the surface and inside the TiO₂ nanotubes, increasing effective adsorption sites. The obtained composite material well retains the structure and functional groups of the two original materials, and while retaining the original force with the target, it achieves a synergistic effect and produces more interactions with the target. Therefore, the extraction efficiency was greatly improved. The recovery efficiency reached 97.7-105.1% with an RSD of less than 6.71%, the detection limit was 0.1-0.2 μg L^-1, and the linear range was 1-200 μg L^-1 with a determination coefficient of 0.9972-0.9994. Owing to the stability of the two original materials, the composite material could be recycled and reused to extract NSAIDs up to 15 times without a loss of the recovery rate. Satisfactory results were obtained when it was used to extract NSAIDs from the Yellow River. These results indicate that the synthesized MIL-101(Fe)@TiO₂ NT material is a promising sorbent to extract NSAIDs at trace concentrations with high efficiency and long lifetimes.

Imine-linked covalent organic frameworks coated stir bar sorptive extraction of non-steroidal anti-inflammatory drugs from environmental water followed by high performance liquid chromatography-ultraviolet detection

In this study, spherical imine-linked covalent organic frameworks (COFs) were fabricated from 2,5-dimethoxybenzene-1,4-dialdehyde (DMTP) and 1,3,5-tris (4-aminophenyl) benzene (TAPB) and named as TAPB-DMTP-COFs. The resulting powders were coated onto bare glass bars via physical-adhesion to obtain TAPB-DMTP-COFs coated stir bars. The self-made stir bars exhibited higher extraction efficiency (74-85%) and faster dynamics (50 min) towards non-steroidal anti-inflammatory drugs (NSAIDs) over ethylene glycol-Silicone (42-68%, 180 min) and polydimethylsiloxane (3-61%, 180 min) coated stir bars. Fourier transform infrared (FT-IR) spectra, X-ray photoelectron spectroscopy (XPS), zeta potential and water contact angle were employed to provide a comprehensive understanding of the adsorption mechanism between the coating and analytes. The results displayed that methoxy group worked as an adsorption site helping the adsorption of interest NSAIDs onto the TAPB-DMTP-COFs coating and hydrogen bonds formed between the O atoms and the analytes. Additionally, the adsorption mechanisms possibly also involved π-π interaction and hydrophobic interaction. Moreover, TAPB-DMTP-COFs coated stir bars exhibited good stability and could be reused more than 60 times. Subsequently, a method by combining TAPB-DMTP-COFs coated stir bar sorptive extraction (SBSE) with liquid chromatography (HPLC)-ultraviolet detector (UV) was established for the determination of four NSAIDs in environmental waters. Under the optimized conditions, the established method showed a wide linear range of 0.2/1-500 μg/L for interest NSAIDs, the limits of detection varied from 0.039 to 0.312 μg/L. Yangtze River water, East Lake water and Spring water were subjected to the proposed method, the recoveries in spiked samples were 84.7-104%, 81.2-101% and 82.6-97.6%, respectively.

MIL-101(Fe)-derived magnetic porous carbon as sorbent for stir bar sorptive-dispersive microextraction of sulfonamides

Using MIL-101(Fe) as the source of carbon and Fe, a magnetic porous carbon (MPC) material with Fe₃C nanoparticles encapsulated in porous carbon was prepared through one-pot pyrolysis under N₂ atmosphere. With MPC as adsorption material, a stir bar sorptive-dispersive microextraction (SBSDME) method was proposed to extract and preconcentrate sulfonamides (SAs) prior to HPLC-DAD determination. To investigate their extraction ability, different MPC materials were prepared under different carbonization temperatures (600, 700, 800, 900, and 1000 °C). The material prepared under 900 °C (MPC-900) exhibited the highest extraction ability for SAs. The as-prepared MPC materials were also characterized by Raman spectroscopy, scanning electron microscopy, X-ray photoelectron spectroscopy, zeta potential, and other techniques. The main parameters that affect extraction were systematically studied. Under optimal conditions, favorable linearity (R² ≥ 0.9938) and detection limits (0.02-0.04 ng mL^-1) of sulfonamides were obtained. The average recoveries for spiked milk and lake water samples ranged from 76.9 to 109% and from 75.4 to 118% with RSDs of 3.10-9.63% and 1.71-11.3%, respectively. Sulfameter and sulfisoxazole were detected in milk sample. Sulfisoxazole was detected in the lake water sample. The MPC-900 material demonstrated excellent reusability. It can be reused 24 times with peak areas having no obvious decline. The method can be applied to extract ultra-trace compounds in complex sample matrices. Schematic presentation of a stir bar sorptive-dispersive microextraction (SBSDME) by using magnetic porous carbon (MPC) composites as sorbent combined with high-performance liquid chromatography for sensitive analysis of sulfonamides in milk and lake water samples.

A magnetic MOF derivative with rich interactions formed under mild preparation conditions for the extraction of non-steroidal anti-inflammatory drugs from the Yellow River

For sorbents, good magnetic properties and rich interactions with targets are important ways to improve the efficiency of magnetic solid-phase extraction (MSPE). The magnetic MOF-101 derivative (MD) was obtained by heat-treating MOF-101 at different temperatures. After a series of characterizations, it was found that MD-350 had the best magnetic properties and retained more functional groups of the original MOF-101, and had better extraction efficiency as compared to MD obtained under other treatment temperatures for the MSPE of four non-steroidal anti-inflammatory drugs (NSAIDs) in water samples, coupled with high-performance liquid chromatography (HPLC). The remaining functional groups of MD-350 can produce more interactions with NSAIDs, such as hydrogen bonding, π-π conjugation, and coordination interactions; good magnetic properties facilitate the separation of the sorbent and the solution. These advantages indicate that the established extraction method demonstrated satisfactory extraction performance: an excellent recovery rate (96.73-100.61%) with a short extraction time (15 min), a wide linear range (4-400 μg L-1) with a determination coefficient of 0.9975-0.9993, a low LOD of 0.2-0.5 μg L-1 and up to 12 times service-life without the loss of the recovery rate. Satisfactory results were also obtained in extracting NSAIDs from Yellow River. All these results indicate that MD-350 prepared under mild conditions has potential as an MSPE sorbent to detect and remove NSAIDs from environmental waters with high efficiency and long service life.

Fabrication of polyethyleneimine modified magnetic microporous organic network nanosphere for efficient enrichment of non-steroidal anti-inflammatory drugs from wastewater samples prior to HPLC-UV analysis

Development of novel functionalized adsorbents for efficient magnetic solid phase extraction (MSPE) is essential for promoting their versatile applications in sample pretreatment. Herein, we report the fabrication of a new polyethyleneimine-600 decorated magnetic microporous organic network nanosphere (Fe₃O₄@MON-PEI₆₀₀) for effective MSPE of trace non-steroidal anti-inflammatory drugs (NSAIDs) from different water samples. The core-shelled Fe₃O₄@MON-PEI₆₀₀ integrates the synergistic effects of Fe₃O₄, MON and PEI₆₀₀, providing facile and effective extraction to NSAIDs via multiple hydrogen bonding, π-π and hydrophobic interactions. The inner MON shell employs π-π and hydrophobic interaction sites and the outer PEI-600 coat acts as the hydrogen bonding doner/receptor, which affords good extraction performance for NSAIDs. Under optimal conditions, the Fe₃O₄@MON-PEI₆₀₀-MSPE-HPLC-UV method gives wide linear range (0.14-400 μg L^-1), low limits of detection (0.042-0.149 μg L^-1), good precisions (intra-day and inter-day RSDs < 4.5%, n = 6), and large enrichment factors (97.0-98.2). Extraction mechanisms and selectivity of Fe₃O₄@MON-PEI₆₀₀ are evaluated in detail. Moreover, Fe₃O₄@MON-PEI₆₀₀ is successfully applied to enrich the trace NSAIDs in different water samples with the concentrations of 0.7 and 0.8 μg L^-1 for 1-naphthylacetic acid, 0.5 and 0.1 μg L^-1 for naproxen as well as 0.7 μg L^-1 for ibuprofen, respectively. The developed method not only affords a novel and efficient magnetic adsorbent for NSAIDs in aqueous media at trace level, but also provides a new strategy for the rational design and synthesis of multiple functionalized MON composites in sample pretreatment.

Hydrophilic carboxyl supported immobilization of UiO-66 for novel bar sorptive extraction of non-steroidal anti-inflammatory drugs in food samples

Herein, the preparation of UiO-66 on frosted glass rod (FGR) was proposed through the coordination interaction of Zr-OH groups and carboxyl sites on FGR. The relative standard deviations (RSDs) of intra-batch and inter-batch were below 8.0% (n = 7). UiO-66-modified FGR (UiO-66@FGR) was applied to the extraction and monitoring of five non-steroidal anti-inflammatory drugs (NSAIDs) by coupling to novel bar sorptive extraction (BSE) with ultra-high performance liquid chromatography (UPLC). Sample volume, stirring rate, extraction time, sample pH value, desorption solvent, and desorption time were investigated. NSAIDs (ketoprofen, flurbiprofen, ibuprofen, naproxen, and diclofenac sodium) were determined at a low limit of detection (0.92 ng/mL) over a wide linear range (10-1500 ng/mL). The developed method was used to analyze NSAIDs in sheep muscle, chicken wing, and milk with recoveries of 80.8%-117.2%, RSDs < 6.5%. Fabricated UiO-66@FGR exhibited excellent reproducibility, stability, and good adsorption property towards NSAIDs in food samples.

Starch-Mg/Al layered double hydroxide composites as an efficient solid phase extraction sorbent for non-steroidal anti-inflammatory drugs as environmental pollutants

Using a co-precipitation method, starch-Mg/Al layered double hydroxide (S-Mg/Al LDH) composites were synthesized. Their physicochemical properties were assessed by Fourier-transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy, and thermo-gravimetric analysis. The quantification of six non-steroidal anti-inflammatory drugs (NSAIDs) was conducted using real samples (e.g., hospital waste water, river water, sewage treatment plant water, and tablet formulations) by gas chromatography-mass spectrometry. For the development of this method, the system was optimized in terms of several key variables (e.g., pH, flow rate, and eluent type/volume). The developed method for NSAIDs exhibited good resolution, sensitivity, reproducibility, and specificity even in complex matrices with limits of detection between 4 and 20 pg/mL. Hence, S-Mg/Al LDH composites were proven to be efficient and fast solid phase extraction (SPE) sorbents for NSAIDs. In addition, each LDH-SPE cartridge showed good reusability without a noticeable change in performance (e.g., up to 30 cycles) and target recoveries between 99.5 - 82.9 %. This work should open up new opportunities for a sesnsitive and sustainable quantitative method for the determination of NSAIDs in complex samples.

Greenness of magnetic nanomaterials in miniaturized extraction techniques: A review

Green analytical chemistry principles should be followed, as much as possible, and particularly during the development of analytical sample preparation methods. In the past few years, outstanding materials such as ionic liquids, metal-organic frameworks, carbonaceous materials, molecularly imprinted materials, and many others, have been introduced in a wide variety of miniaturized techniques in order to reduce the amount of solvents and sorbents required during the analytical sample preparation step while pursuing more efficient extraction methods. Among them, magnetic nanomaterials (MNMs) have gained special attention due to their versatile properties. Mainly, their ability to be separated from the sample matrix using an external magnetic field (thus enormously simplifying the entire process) and their easy combination with other materials, which implies the inclusion of a countless number of different functionalities, highly specific in some cases. Therefore, MNMs can be used as sorbents or as magnetic support for other materials which do not have magnetic properties, the latter permiting their combination with novel materials. The greenness of these magnetic sorbents in miniaturized extractions techniques is generally demonstrated in terms of their ease of separation and amount of sorbent required, while the nature of the material itself is left unnoticed. However, the synthesis of MNMs is not always as green as their applications, and the resulting MNMs are not always as safe as desired. Is the analytical sample preparation field ready for using green magnetic nanomaterials? This review offers an overview, from a green analytical chemistry perspective, of the current state of the use of MNMs as sorbents in microextraction strategies, their preparation, and the analytical performance offered, together with a critical discussion on where efforts should go.

Preparation of magnetic mesoporous metal-phenolic coordination spheres for extraction of crystal violet and leuco-metabolites in fish

To address the undesirably low porosity of phenolic resin, a new material termed magnetic mesoporous metal-phenolic coordination spheres (Fe₃O₄@Co-TA) was synthesized by chelating tannic acid (TA) with metal ions. Fe₃O₄@Co-TA was characterized by transmission electron microscopy, scanning electron microscopy, hysteresis loop (B-H) analysis, Fourier-transform infrared spectroscopy, and N₂ adsorption-desorption. The results indicated that the new material comprises mesopores (2 nm and 3 nm) and exhibits a good magnetic response (44 emu/g). Combined with high-performance liquid chromatography (HPLC), a novel method for the detection of crystal violet (CV) and leucocrystal violet (LCV) by magnetic solid-phase extraction was established. Under the optimal extraction conditions, the linear ranges of CV and LCV detection were 0.2‒60 μg/L and 0.04‒40 μg/L, the detection limits were 0.04 μg/L and 0.008 μg/L, and the enrichment factors were 435 and 460, respectively. Fe₃O₄@Co-TA was reused ten times without significant reduction of the extraction ability. This method was successfully used for the detection of CV and LCV in fish samples, providing an effective technique for food safety monitoring and quality control.

Restricted access supramolecular solvent based magnetic solvent bar liquid-phase microextraction for determination of non-steroidal anti-inflammatory drugs in human serum coupled with high performance liquid chromatography-tandem mass spectrometry

A hexafluroisopropanol (HFIP)-alkanol supramolecular solvent (SUPRAS) based magnetic solvent bar (MSB) liquid-phase microextraction (LPME) method was proposed for extraction of non-steroidal anti-inflammatory drugs (NSAIDs, including ketoprofen, naproxen, indomethacin and diclofenac) in human serum. The restricted access HFIP-alkanol SUPRAS was prepared by injecting a mixture of HFIP and alkanol into water. A stainless-steel needle was inserted into a piece of hollow fiber to prepare a magnetic bar. Then the magnetic bar was dipped in SUPRAS to impregnate the wall pores of the hollow fiber, followed by placing it into the serum sample for extraction. Only 4 μL of SUPRAS was consumed per bar. The MSB not only functioned for stirring, but also played the role of extraction and magnetic separation. Under the optimal extraction conditions (seven MSBs, extraction time 33 min and stirring rate 730 rpm), which was obtained by one variable-at-a-time and response surface methodology, the novel MSB-LPME was coupled with high performance liquid chromatography-tandem mass spectrometry to determine NSAIDs in human serum. The method showed a good linear relationship (correlation coefficients ≥ 0.9939). Method limits of detection and method limits of quantitation were in the range of 0.25-0.95 μg L^-1 and 0.83-3.16 μg L^-1, respectively. The recoveries for the spiked human serum samples ranged from 86.8% to 125.1% with intra- and inter-day relative standard deviations less than 9.2% and 18.1%, respectively. Moreover, the method did not require a protein precipitation step, and matrix effects of 72.8%-117.7% showed little interference with mass spectrometry detection, which was due to the double cleanup provided by the restricted access property of SUPRAS and the filtration capacity of hollow fiber. The HFIP-alkanol SUPRAS-based MSB-LPME method proved to be simple, highly efficient and environment-friendly for the pretreatment of serum/plasma.

MOF-derived cluster-shaped magnetic nanocomposite with hierarchical pores as an efficient and regenerative adsorbent for chlortetracycline removal

The presence of large amounts of antibiotic residues can potentially threaten environmental sustainability and human health. Thus, it is imperative to develop convenient and effective technologies for eliminating antibiotics from aquatic environments, which are major contaminant reservoirs. Herein, based on Zn/Fe-MIL-88B, we designed and synthesized a magnetic nanocomposite (MC) that contains hierarchical pores and as an effective and regenerative adsorbent for the removal of chlortetracycline (CTC) from water. The characteristics of the MC and its CTC adsorption performance were investigated systematically. The synthesized MC sample pyrolyzed at 800 °C (MC-800) consisted of metallic iron and N/O-doped graphitic carbon along with cluster-like particles with a mesoporous structure. Further, the adsorption of CTC on MC-800 (maximum adsorption amount of 1158.0 mg/g) could be described using the Freundlich isotherm model and a pseudo-second-order model, indicating that the surface of MC-800 was heterogeneous. The adsorption is likely driven by weak chemical forces, including hydrogen bond formation, cation-π electron donor-acceptor (EDA), and π-π EDA interactions. Finally, MC-800 could be recovered readily through facile magnetic separation and regenerated such that its adsorption rate remained higher than 85% even after five cycles.

Amine-functionalized magnetic activated carbon as an adsorbent for preconcentration and determination of acidic drugs in environmental water samples using HPLC-DAD

In the present study, a convenient and highly effective method was developed for the quantification of acidic drugs in wastewater and river water samples. Ultrasonic-assisted magnetic solid phase extraction employing magnetic waste tyre-based activated carbon nanocomposite functionalized with [3-(2-aminoethylamino)propyl]trimethoxysilane as a cost-effective and efficient adsorbent was used for the extraction and preconcentration of acidic drugs (naproxen [NAP], ketoprofen (KET) and diclofenac [DIC]). The quantification of target analytes was achieved by high‐performance liquid chromatography with diode array detector. Under optimum conditions, the detection limit, quantification limit and relative standard deviation obtained for the analytes of interest ranged from 0.38 to 0.76, 1.26 to 2.54 µg L−1 and 2.02 to 4.06%, respectively. The applicability of the developed method was assessed by the spike recovery tests and the relative recoveries proved that the method is reliable for the determination of acidic drugs in wastewater. Thereafter, the method was applied successfully for the determination of NAP, KET and DIC in river water, influent and effluent wastewater.

Facile synthesis of magnetic sulfonated covalent organic framework composites for simultaneous dispersive solid-phase extraction and determination of β-agonists and fluoroquinolones in food samples

In this work, an efficient method for the determination of β-agonists and fluoroquinolones was established, based on a mixed-mode sorbent of magnetic sulfonated covalent organic framework composites. By coupling with HPLC-MS/MS, the main factors that affect the extraction procedure were optimized. Under the optimal conditions, the proposed HPLC-MS/MS method was successfully utilized for the extraction of β-agonists and fluoroquinolones in milk and pork meat samples. The method showed good linearities (R² ≥ 0.9916), and low LOQs of 0.1-0.2 ng g^-1 for β-agonists and fluoroquinolones. The adsorption mechanism was investigated with the assistance of quantum chemistry calculation method, and it is worth noting that the sorbent relied mainly on the multiple adsorption mechanisms, including π-π stacking, hydrophobic, electrostatic attraction and hydrogen-bonding interactions. This work not only provides a simple method for the preparation of a mixed-mode sorbent, but also a routine analysis strategy for monitoring the illegal use of β-agonists and fluoroquinolones.