Sorbent For Extraction Research Articles

Green construction of magnetic azo porous organic polymer for highly efficient enrichment and detection of phenolic endocrine disruptors

Porous organic polymers (POPs) are prominent sorbents for effective extraction of endocrine disrupting chemicals (EDCs). However, green and sustainable construction of functional POPs is still challenging. Herein, we developed a magnetic azo POP (Mazo-POP) for the first time using hydroxy-rich natural kaempferol and low-toxic basic fuchsin as monomers through a diazo coupling reaction. The Mazo-POP exhibited excellent extraction capabilities for EDCs with a phenolic structure. Consequently, it was used as a magnetic sorbent for extracting phenolic EDCs from water and fish samples, followed by ultrahigh-performance liquid chromatography-tandem mass spectrometric detection. The Mazo-POP based analytical method afforded a good linearity of 0.06–100 ng mL−1 and 0.3–500 ng g−1 for water and fish samples respectively, with detection limits (S/N = 3) of 0.02–0.5 ng mL−1 and 0.1–1.5 ng g−1, respectively. The method recovery was from 85.2% to 109% and relative standard deviation was less 5.3%. Moreover, the effective adsorption was mainly contributed by hydrogen bond, π-π interaction, pore filling and hydrophobic interaction. This work not only provides an efficient method for sensitive determination of phenolic EDCs, but also highlights the significance of green preparation of environmentally friendly sorbents for enriching/adsorbing pollutants.

The potential of three different adsorbents in solid‐phase extraction of antihistaminic and antimigraine drugs from water samples using ultra‐high‐performance liquid chromatography‐ultraviolet analysis

AbstractIn this study, eight pharmaceuticals belonging to two classes, antihistaminic and antimigraine, were considered. Ultra‐performance liquid chromatography‐diode array detection was set up and gradient elution was used. The mobile phase was composed of acetonitrile and trifluoroacetic acid solution. Chromatographic separation was carried out with a run time of 9 min. The preconcentration of eight studied solutes was realized by micro solid‐phase extraction. Multiwalled carbon nanotubes, cetyltrimethylammonium bromide‐titanium dioxide nanotubes, and C‐18 bonded silica solid‐phase extraction (SPE) sorbents were evaluated and compared concerning recoveries. The results of the optimization of factors affecting the extraction efficiency including sample volume, the elution solvent type, and its volume are reported. For validation of the analytical procedure, specificity, linearity, precision, accuracy, limit of detection, and limit of quantification were evaluated. The developed method was successfully applied to the analysis of wastewater treatment samples. The extraction recoveries of pharmaceutical substances were above 81.23% for the three SPE sorbents. The extraction method was selective and the detection and quantification limits were between 0.004–0.02 and 0.01–0.06 μg/L, respectively. All the results indicated the potential application of the three studied SPE sorbents for the extraction of selected pharmaceuticals from wastewater.

Preparation of mixed-mode weak cation exchange magnetic solid-phase extraction sorbent and its application in the extraction of 21 illicit drugs from wastewater

The detection of illicit drugs in wastewater can effectively monitor and evaluate the trend of illicit drug abuse. A novel mixed-mode cation exchange magnetic sorbent Fe3O4 @poly(ST/DVB/MA-COOH) was prepared and firstly applied as magnetically dispersed solid phase extraction material to efficiently, rapidly, and selectively extract 21 illicit drugs from wastewater. The selectivity of the sorbent was mainly attributed to the electrostatic interaction. The effects of Fe3O4 @poly(ST/DVB/MA-COOH) preparation and extraction conditions on the adsorption performance were thoroughly discussed. Among the 21 illicit drugs, the absolute extraction recovery values for 19 illicit drugs were greater than 80 % and the entire adsorption process could be achieved in one minute. Subsequently, the Fe3O4 @poly(ST/DVB/MA-COOH) sorbent combined with UHPLC-MS/MS was used to establish a quantitative method for the effectively extracted 19 illicit drugs in wastewater. The method had a good determination coefficient in the range of 0.2–200 ng/L and the limits of detection of the method were 0.03–0.67 ng/L. The spiked recovery values were in the range of 87.0–119.6 %. Finally, the method was successfully applied to the detection of 19 illicit drugs in wastewater samples and also compared with the commonly used SPE method. The obtained results indicate that Fe3O4 @poly(ST/DVB/MA-COOH) has great advantages in the detection of illicit drugs in wastewater.

Fluorine-functionalized covalent organic framework as efficient solid phase extraction sorbent for adsorption of aflatoxins in nuts

In this study, a new fluorine-functionalized covalent organic framework (F-COF) was designed and fabricated by the direct polycondensation of tris(4-aminophenyl)amine and 2,3,5,6-tetra-fluoroterephthaldehyde for the first time. F-COF exhibited a remarkably enhanced adsorption capability compared with that of the fluorine-free COF. The favorable adsorption of aflatoxins was attributed to multiple interactions including pseudo hydrogen bond, F-O, π-π, F-π interactions and hydrophobic interactions between F-COF and aflatoxins. By coupling F-COF based solid phase extraction with high-performance liquid chromatography equipped with fluorescence detector, a rapid and sensitive method for determining aflatoxins (aflatoxin B1, B2, G1 and G2) in nuts (peanuts and pistachios) was established. Under optimal conditions (35 mg F-COF, 100 mL sample solution, 3 mL min−1 as sample loading rate, pH<7, 0.2 mL acetonitrile as desorption solvent), the limits of detection for aflatoxins were 0.02–0.30 ng g−1. The linear range was 0.08–16.0 ng g−1 and the recoveries of the F-COF-based method were 83.5–114 % with relative standard deviations less than 8.0 %.

Novel, alternative analytical methodology for determination of antimicrobial chemicals in aquatic environments and public use assessment: Extraction sorbent, microbiological sensitivity, stability, and applicability

BackgroundAssessing antimicrobial chemicals from wastewater source to recipient water systems is crucial in planning effective, policy-related interventions for antimicrobial resistance (AMR) risk mitigation. However, the capability of related analytical methods for AMR assessment has not been explored previously. There is also a lack of knowledge on the effectiveness of alternative extraction sorbents with ion-exchange functions, and little information on chemical stability from sampling to analysis as well as preservative options. Hence, our study aims to address the clear need for advanced, broad-range and microbiologically-sensitive methodologies, paired with thorough stability assessments. ResultsOasis® WCX ion-exchange was for the first time employed in solid-phase extraction (SPE) for antibacterials, antifungals, antivirals and human metabolites in various water matrices. Analysis was performed using liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) on a biphenyl analytical column. The optimized and validated method provided satisfactory accuracy, precision, and recovery for 53 compounds via LC-MS/MS direct injection and for up to 35 compounds via SPE-LC-MS/MS. Method quantification limits (MQLs) were determined in groundwater (0.33–54 ng L−1), surface water (0.53–75 ng L−1), effluent wastewater (2.5–470 ng L−1), and influent wastewater (11–650 ng L−1). As a novel approach, MQLs were compared with minimum inhibitory concentrations, to confirm our method's microbiological sensitivity for studying AMR. Stability assessment revealed that most compounds remained stable in standard solution at −80 °C for six months, in various waters at −20 °C for eight weeks, and during 24-h sampling at 4 °C. Sodium azide was a better preservative than sodium metabisulfite. SignificanceOur study is an added value to the analytical methodology for water measurements of antimicrobial chemicals, in which it provides a novel, alternative method that is robust and overall more sensitive than others using generic Oasis® HLB sorbents and C18 analytical columns in SPE-LC-MS/MS. Also, the comprehensive data on antimicrobial stability helps reduce methodological uncertainty for future studies. Our method shows sufficient microbiologically-sensitive and thus is suitable for future (inter)national regulatory water monitoring of AMR.

The simultaneous measurement of atomoxetine, venlafaxine, and duloxetine in actual water and biological samples requires the creation of a unique magnetic dispersive micro solid phase extraction sorbent based on MOF-on-MOF

ABSTRACT Atomoxetine, venlafaxine, and duloxetine are three antidepressant drugs widely prescribed to treat this disorder. Determining these drugs is a major challenge due to their low concentration and high matrix effects on biological samples. Dispersive micro solid phase extraction was developed as a sample preparation strategy to extract these drugs in real water and biological samples. A novel sorbent containing a magnetic MOF-on-MOF was prepared to extract these drugs using Fe3O4 nanoparticle and Sol-gel technique. The microextraction procedure was optimised under two steps using experimental design. Three factors, including pH, sorbent amount, and desorption solvent volume, significantly affected the extraction of analytes and optimised using a central composite design. The optimum value of pH, sorbent amount, and desorption solvent volume was 29 mg, 6.5, and 150 µL. Under optimum conditions, the linear ranges for measuring atomoxetine, venlafaxine, and duloxetine in water samples were 1.42–496, 0.43–472, and 0.73–459 ng mL−1, respectively. The detection limits of atomoxetine, venlafaxine, and duloxetine were 0.4, 0.1, and 0.2 ng mL−1. High and proper preconcentration factors ranged from 462.4–511.4 in distiled water samples and 450.7–489.8 in urine samples were obtained to determine atomoxetine, venlafaxine, and duloxetine with three concentrations of 5.0, 20.0, and 100.0 ng mL−1, respectively. Inter-day and intra-day RSD% were calculated by triplicate determination of atomoxetine, venlafaxine, and duloxetine at three concentrations of 10.0, 50.0 and 100.0 ng mL−1 and were between 3.2–4.3% and 3.8–4.6% in distiled water samples, and 4.8–5.7% and 5.0–5.8% in urine samples, respectively. Analysis of tap, river water, and two urine samples as real water and biological samples under optimum conditions exhibited recovery and standard deviation in the ranges of 90.2–96.9% and 3.84–5.74%, respectively, confirmed the proper ability of the method to determine atomoxetine, venlafaxine, and duloxetine in natural water and biological samples.

Development of a universal sol–gel sorbent for fabric phase sorptive extraction and its application in tandem with high performance liquid chromatography-ultraviolet detection for the analysis of phthalates in environmental and drinking water samples

Most sorbent-based sample preparation methods are designed to interact with a class of analytes i.e., a polar sorbent for polar analytes, a non-polar sorbent for non-polar analytes, an ion-exchange sorbent for ionized compounds. A big challenge surfaces when making a choice of an appropriate sorbent when there is a mixture of compounds of varying polarities and ionization states in the complex sample matrices. Hence, the aim of this study was to develop a universal sol–gel sorbent coating for fabric phase sorptive extraction that would effectively and simultaneously extract polar, nonpolar, organic acids and bases via different intermolecular/interionic interactions. The universal sol–gel sorbent coated fabric phase sorptive extraction membrane was created by exploiting sol–gel surface coating technology to implant different functional moieties, ion exchanging ligands and an organic polymer that results in a 3-D organic–inorganic hybrid structure on the fabric substrate with a high level of selectivity/affinity for the target compounds. The preconcentrated extracts containing the isolated phthalates after the fabric phase sorptive extraction procedure were injected into the high-performance liquid chromatography-ultraviolet detection (HPLC-UV) system for the quantification. The FPSE-HPLC-UV method demonstrated a linear range between 50 and 1000 ng/mL for dimethyl phthalate, diethyl phthalate, dipropyl phthalate, diallyl phthalate, benzyl butyl phthalate, 1–10000 ng/mL for di-n-heptyl phthalate, 1–5000 ng/mL for di-n-heptyl phthalate, 10–5000 ng/mL for di-n-ethyl hexyl phthalate and 100–7500 ng/mL di-n-octyl phthalate. The intra-day and inter-day reproducibility (in terms of percentage relative standard deviation, %RSD) did not exceed 13.6. This method proves to be a selective, accurate, reproducible, cheap, and fast analytical approach for the quantitative and qualitative determination of the phthalates which is useful in crafting regulations for phthalates content in beverages and juices as well as in environmental monitoring.

Assessment of Molecularly Imprinted Polymers as Selective Solid-Phase Extraction Sorbents for the Detection of Cloxacillin in Drinking and River Water.

This paper describes a new methodology for carrying out quantitative extraction of cloxacillin from drinking and river water samples using a molecularly imprinted polymer (MIP) as a selective sorbent for solid-phase extraction (MISPE). Several polymers were synthesized via thermal polymerization using cloxacillin as a template, methacrylic acid (MAA) as a functional monomer, ethyleneglycoldimethacrylate (EGDMA) as a cross-linker and different solvents as porogens. Binding characteristics of the adequate molecularly imprinted and non-imprinted (NIP) polymers were evaluated via batch adsorption assays following the Langmuir and Freundlich isotherms and Scatchard assays. The parameters related to the extraction approach were studied to select the most appropriate polymer for cloxacillin determination. Using the optimized MIP as the SPE sorbent, a simple sample treatment methodology was combined with high-performance liquid chromatography (HPLC) to analyze cloxacillin residues in drinking and river water. Under the optimum experimental conditions, the MISPE methodology was validated using spiked samples. The linearity for cloxacillin was assessed within the limits of 0.05-1.5 µg L-1 and the recovery percentage was higher than 98% (RSD < 4%). The limits of detection and limits of quantification were 0.29 and 0.37 µg L-1 and 0.8 and 0.98 µg L-1 for drinking and river water, respectively. The selectivity of MIP against other ß-lactam antibiotics with similar structures (oxacillin, cefazoline, amoxicillin and penicillin V) was studied, obtaining a good recovery higher than 85% for all except cefazoline. The proposed MISPE-HPLC methodology was successfully applied for the detection of cloxacillin in drinking water from Canal de Isabel II (Madrid) and river water from the Manzanares River (Madrid).

Simultaneous extraction of hydroxylated polycyclic aromatic hydrocarbons and catecholamines with magnetic boronic acid hypercrosslinked polymers

Urinary hydroxylated polycyclic aromatic hydrocarbons (OH-PAHs) and catecholamines (CAs) are important biomarkers of PAHs exposure. In this study, a novel magnetic boronic acid hypercrosslinked composite (Fe3O4@HCP-BA) is synthesized using a facile one-pot strategy and applied as a sorbent for the simultaneous extraction of OH-PAHs and CAs in urine samples. The synthesized Fe3O4@HCP-BA composites are characterized by rich pore structure, highly specific surface area, good magnetic response, and excellent selectivity and adsorption efficiency (range: 65.26–496.71 and 1227.3–1581.8 µmol g−1 for CAs and OH-PAHs, respectively). The mechanisms governing the adsorption of the OH-PAHs and CAs to the Fe3O4@HCP-BA composites were systematically studied via adsorption kinetics, isotherm models, XPS characterization, and molecular simulation. The resultant Fe3O4@HCP-BA composite-based MSPE/HPLC-FLD method exhibited good linearity (R2 > 0.9916), low limits of detection (0.2–0.3 pg mL−1 and 0.2–0.3 ng mL−1 for OH-PAHs and CAs, respectively), and good precision (intra-day and inter-day RSDs < 11.1%). The analysis of CAs and OH-PAHs in the urine samples from 14 smokers and 14 non-smokers revealed a positive correlation between the concentrations of CAs and OH-PAHs. Our findings not only establish the proposed method as a green, environmentally friendly, and simple strategy for preparing magnetic adsorbents, but also confirm it as a promising alternative method for accurate determination of OH-PAHs and CAs in biological samples.

Preparation of hypercrosslinked porous polymer with manifold functional groups for sensitive determination of phenylurea herbicides in beverages and celtuce samples.

Wide use of phenylurea herbicide has caused serious residue problem and threaten human health. It is important to develop viable method for their sensitive determination. Herein, a multi-functionalized porous polymer was prepared by crosslinking hexafluorobisphenol A with pyromellitic dianhydride. Using the multi-functionalized porous polymer as solid phase extraction sorbent, combined with high performance liquid chromatography, a sensitive method was established for determining phenylurea herbicides in beverages and celtuces. High sensitivity was achieved, with method detection limit (S/N=3) of 0.01---0.025ngmL-1 for beverages, 1.70ngg-1 for celtuce, and quantitation limits of 0.03---0.10ngmL-1 for beverages, 5.00ngg-1 for celtuce. The method recoveries were 80.5---120.0 % with relative standard deviations lower than 6.1%. Adsorption mechanism mainly involved F-π, F-O, π-π, polar interactions and hydrogen-bonding interactions. This study offers a simple protocol to develop multi-functional sorbents for extraction of organic pollutants.

Green preparation of magnetic pyrene-based hyper-cross-linked polymer using dual-purpose ferric chloride reagent for extraction of polycyclic aromatic hydrocarbons from natural water bodies

A magnetic hyper-cross-linked polymer Fe3O4/HCPPYR was prepared using pyrene as the monomer and formaldehyde dimethyl acetal (FDA) as the cross-linking agent. The objective of green chemistry was achieved by employing FeCl3 during the synthesis, as it played a dual role of a catalyst for the Friedel-Crafts reaction and an iron source for the synthesis of magnetic Fe3O4, thus maximizing efficiency and minimizing waste. Fe3O4/HCPPYR was applied as a sorbent for magnetic solid-phase extraction (MSPE) to extract fifteen polycyclic aromatic hydrocarbons (PAHs) from water. The effects of different parameters such as the quantity of adsorbent, the extraction time, the desorption conditions, the pH value and the effect of the salt concentration on the extraction efficiency were optimized. A simple and efficient method in combination with gas chromatography-mass spectrometry (GC–MS) (Fe3O4/HCPPYR−MSPE/GC–MS) was developed and successfully applied for the detection of PAHs in environmental water samples The analytical method showed LODs in the range of 0.004−0.06 µg L−1, which proved to be adequate for the detection all 15 PAHs at trace concentration. Spiked recoveries of PAHs in actual water samples ranged from 85.2 % to 118.5 % with relative standard deviations (RSDs) below 10.2%. These results indicate that the method has a good potential for reusability and possesses excellent sensitivity. This study showcased the potential of Fe3O4/HCPPYR composites in effectively removing organic pollutants from the aqueous environments, demonstrating their ability for water treatment applications.

Room-temperature synthesis of magnetic thiophene-based covalent organic frameworks for derivatization-assisted GC–MS analysis of estrogens in environmental water

Under room temperature conditions, a novel thiophene-based magnetic covalent organic framework (COF) was ingeniously synthesized for the first time, utilizing an uncomplicated and benign Schiff base reaction between 4,4′,4″,4‴-(pyrene-1,3,6,8-tetrayl)tetraaniline (PyTTA) and 2,2′-dithiophene-5,5′-dicarboxaldehyde (BTDA), with Fe3O4 serving as the magnetic nucleus. The fabricated Fe3O4@Py-BTDA COF nanocomposite displays superior crystallinity, homogenous pore size distribution, elevated magnetic responsiveness, and extraordinary thermal and chemical stability, which is an ideal sorbent for magnetic solid phase extraction (MSPE) of estrogens in environmental water samples. The presence of thiophene groups within the Fe3O4@Py-BTDA COF significantly bolsters the π-π interaction between the COF and the target analytes, and meanwhile provides sufficient hydrophobic sites and unique p-π interactions, thus becoming a crucial factor in augmenting the extraction efficiency of estrogens. Due to the high boiling point of estrogens, derivatization is necessary before gas chromatography–mass spectrometry (GC–MS) analysis. So, the conditions of derivatization, extraction and desorption were then systematically optimized. Under the optimal MSPE conditions, a rapid and sensitive method coupling MSPE with GC–MS was developed for the analysis of five estrogens in environmental water samples. The method showed good linearity (r2 > 0.9997) in the range of 0.05–100 μg L−1, low detection limits (4.0–7.0 ng/L), good spiked recoveries (91.56 %-105.80 %), and satisfactory relative standard deviations (RSD, less than 7.4 %). In addition, the method was successfully applied to the determination of estrogens in Yangtze River water, East Lake water, and tap water, with the recoveries in the range of 81.33 %-113.95 % and the RSDs in the range of 0.12 % to 7.69 % at different spiked levels. Estrone (E1) and estradiol (E2) were detected in the Yangtze River water with concentrations of 0.31 μg L−1 and 0.08 μg L−1. And, the prepared Fe3O4@Py-BTDA COF nanocomposite still provides good extraction effect after five cycles of application. The developed method is rapid, simple, sensitive, and environmentally friendly, and has good application in the analysis and determination of estrogens in environmental water samples.

NiCo2O4@ZnCo2O4 nanomaterial for selective and fast dispersive solid phase micro-extraction of manganese and lead in water, tea and cinnamon samples followed by FAAS determination

NiCo2O4@ZnCo2O4 nanomaterial was synthesized and XRD, FTIR, FESEM, zeta potential measurements, and BET were used for characterization. It was first used as a sorbent for simultaneous dispersive solid phase micro extraction (d-SPµE) of manganese and lead in water, tea and cinnamon. The determination of analytes was made by FAAS. The pH, elution conditions, sample volume, contact times, and effect of competing ions on the d-SPµE of manganese and lead was examined. The optimal pH, and eluent for manganese and lead were found to be 4 and 2 mol/L hydrochloric acid (3 mL), respectively. The adsorption was carried out without vortexing and contact time for elution was only 30 s. The LOD and PFs of the d-SPµE for manganese and lead were 1.7 μg L−1, 16.7 for manganese and 4.0 μg L−1, 33.3 for lead, respectively. The tolerable concentrations of interfering ions for analytes were rather high. The accuracy of d-SPµE was confirmed with analyses of BCR-482 Lichen, TMDA-70.2 Lake water, and NIST RM 8704 Buffalo River Sediment and applying d-SPµE to spiked sea water, wastewater, dam water, tea and cinnamon.

3D printed stir bar sorptive extraction coupled with high performance liquid chromatography for trace estrogens analysis in environmental water samples

BackgroundAny imaginary shape with good preparation reproducibility can be made by 3D printing technology, and it has been applied in various fields. Comparatively, its applications in sample pre-treatment are relatively less, most of which involves making extraction sorbents and producing non-functionalized devices for support assistance. 3D printing has not been applied to fabricate stir bars in stir bar sorptive extraction, mainly due to the lacking of suitable printing feedstocks. This work aimed to fabricate stir bars by 3D printing, reducing the manufacturing cost and steps and improving preparation reproducibility. (90) ResultsBy using fused deposition modeling technique and porous filament printing feedstock, stir bars were fabricated without any modifications. Adsorption performance of 3D printed stir bars were investigated for substances with different structures and polarities. Five estrogens with adsorption efficiencies of over 80 % were selected as the representatives. The 3D printed stir bars exhibited good preparation reproducibility (2.9–4.4 %) and higher extraction recoveries (73–81 %) for five estrogens than commercial polydimethylsiloxane coated stir bars (13–69 %) in a shorter time (90 vs 120 min). They showed long lifespan (160 times) with good mechanical properties and merited reduced manufacturing cost (0.064 $ per bar) and manual operation. A method of stir bar sorptive extraction coupled with high performance liquid chromatography was proposed for trace analysis of estrogens in environmental water. Under the optimized conditions, the linear ranges for estrogens were 0.5–200 μg/L with LODs of 0.13–0.17 μg/L. (136) SignificanceThe feasibility of fused deposition modeling in stir bar fabrication was demonstrated, along with the potential of porous filament printing feedstock as the sorbent for substances with medium polarity. 3D printed stir bars were featured with excellent preparation reproducibility, long lifespan, and good mechanical properties. The stir bar fabrication method can be used for mass production with minimal differences in products performance. (62)

Design of magnetic multivariate metal–organic framework for high-efficient adsorption and rapid magnetic separation of bisphenol pollutants

Herein, a magnetic multivariate metal–organic framework (MTV-MOF) named as 95.7 %BTB/MOF-525@Fe3O4 was synthesized by one-pot mixing ligand strategy. The magnetic MTV-MOF exhibited large specific surface area (320 m2·g−1) and high porosity. The 95.7 %BTB/MOF-525@Fe3O4 was used as sorbent for extraction and enrichment of bisphenol pollutants (BPs). The experimental results demonstrated that adsorption kinetics and isotherms conform to pseudo-second-order model and Langmuir model. The maximum adsorption capacities for bisphenol F, bisphenol A, bisphenol B, bisphenol AF were 275.1, 233.6, 302.1 and 277.2 mg·g−1, respectively. With 95.7 %BTB/MOF-525@Fe3O4 as sorbent, the magnetic solid phase extraction coupling HPLC was used to detect trace BPs in environmental water. The limits of detection were determined as between 0.067 and 0.167 ng·mL−1. The enrichment factors were in the range of 242–295. The recoveries were ranged from 79.4 to 103 % with relative standard deviations not higher than 8.85 %. In addition, the recovery rate of sorbent remained above 80 % after 21 times of reuse. The work provides an effective material for extraction and removal of BPs in the environment.

Novel oligonucleotide-based sorbent for the selective extraction of cadmium from serum samples

The objective was to develop a sorbent functionalized with aptamers for the selective extraction of cadmium from biological samples. Two oligonucleotide sequences reported in literature as specific to cadmium were covalently grafted on activated Sepharose, with grafting yields of 45%. Once the supports packed in cartridges, a thorough study of the percolation conditions favoring Cd(II) retention was performed, demonstrating the importance of the nature of this medium. A high selectivity was reached when applying the optimal conditions as a recovery of 85% was obtained using the sorbent functionalized with one of the specific aptamers and only 1% on the control sorbent grafted with a scramble sequence. A high specificity was also obtained as recoveries for most of other ions were lower than 15%. The capacity of this oligosorbent estimated to 180 ng of Cd(II) for 30 mg of support was perfectly adapted to the trace analysis of Cd(II). The extraction procedure was then applied to a serum sample which was first subjected to acid precipitation. The initial concentration of cadmium in the serum was estimated to 1.83 µg/L using standard addition method and an extraction yield of 75 ± 1.6% was measured. Comparison of these results with those obtained without oligoextraction (recovery of 57%) showed a significant reduction of matrix effects in ICP-MS thanks to the use of the oligosorbent, underlining its interest for a more reliable quantification of Cd(II). This result was confirmed by performing the oligoextraction protocol on a certified serum.

Synthesis, characterization and application of cross-linked functional terpolymer through epoxy group as sorbent for extraction of cadmium from waters and foods: Multivariate optimization

The purpose of this study was to develop a selective sorbent for cadmium ions (Cd(II)) enrichment in orbital shaker assisted solid phase microextraction (OS-SPME) from different aqueous and food samples. A maleic anhydride-styrene-glycidyl methacrylate (MA-St-GMA) terpolymer was synthesized and characterized in detail. Experimental variables of sample preparation step were optimized using a central composite design (CCD). The final determination step was performed using flame atomic absorption spectroscopy (FAAS). The MA-St-GMA sorbent exhibited a high adsorption capacity (195.9 mg g−1) for the Cd(II) ion. The developed method under optimal conditions provides satisfactory performance and a significant improvement compared to other protocols available in the literature. The linear range and detection limit of the method is 0.1–130 ng mL−1 and 0.03 ng mL−1, respectively. The robustness, intraday/interday precision, selectivity, and accuracy of the method were investigated. To further validate the method, a dedicated series of analysis was performed using certified reference materials (CRMs). This part of the study confirmed the applicability of the method for routine analysis. The OS-SPME-FAAS method was validated using water and food samples. Relative standard deviations and recovery for real-world samples were in ranges 1.7–2.2 % and 95.5–98.5 %, respectively. As a result, the MA-St-GMA sorbent showed that it could quantitatively extract Cd(II) ions from aqueous solution.

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

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

Reduced graphene oxide-zinc iron oxide nanomaterial as selective dispersive solid-phase extraction sorbent for extraction and enrichment of aflatoxins from milk combined with UHPLC-MS/MS analysis

Fungal species capable of producing aflatoxins frequently contaminate the feed provided to dairy animals, leading to the subsequent occurrence of aflatoxin contamination in milk. Milk is renowned for its exceptional nutritional composition, and the consumption of milk contaminated with aflatoxins by humans can engender a multitude of health complications. In this study, reduced graphene oxide zinc iron oxide (rGO-Zn/Fe2O4) nanomaterial was utilized as a dispersive solid phase extraction adsorbent to separate and enrich aflatoxins (aflatoxin B1, aflatoxin B2, aflatoxin G1, aflatoxin G2, and aflatoxin M1) from milk. The rGO-Zn/Fe2O4 nanomaterial was morphologically characterized by scanning electron microscopy, transmission electron microscopy, and X-ray diffraction, indicating that Zn/Fe2O4 nanoparticles were embedded on the surface of rGO. The acetonitrile/formic acid (99/1, v/v) combined with ultrasonic treatment for a duration of 40 min expressed an efficient extraction solvent. Employing the matrix-spiked technique, different parameters of the dispersive solid-phase extraction (d-SPE) method were meticulously optimized, yielding the following conditions: 2% acetonitrile as loading solvent, 15 mg of rGO-Zn/Fe2O4 as the adsorbent quantity, 15 min of ultrasonication as adsorption time, and n-hexane as the washing solvent. The desorption reagent was 5 mL acetonitrile, with a desorption time of 5 min. The combination of the dispersive solid-phase extraction (d-SPE) technique with validated UHPLC-MS/MS quantitative analysis demonstrated excellent selectivity, a robust linear relationship (R2 ≥ 0.994), remarkable sensitivity (limit of quantification ranging from 0.006 to 0.013 µg/L), and satisfactory recovery rates of 78%–104% at three different matrix-spiked levels. Moreover, the method exhibited precision with relative standard deviations (RSD) ranging from 2.4% to 10.8%. Following appropriate pretreatment procedures, the milk samples underwent rigorous aflatoxin analysis, leading to the identification of AFM1 presence in all of the examined milk samples (n = 9). However, the contamination levels detected were found to be within the permissible limits as defined by regulatory standards.

Synthesis of Modified Magnetic Graphene Oxide with Mesoporous Silica for Extraction of the Pharmaceutical Compound Quercetin.

In this study, magnetic mesoporous silica-Fe3O4-graphene oxide nanoparticles (Fe3O4@GO@mSiO2) were synthesized and used as sorbents for magnetic solid-phase extraction (MSPE) of trace amounts of quercetin in natural samples (spinach, green pepper, dill, and red onion). The sorbent produced was characterized by Fourier transform infrared (FTIR), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDAX), X-ray diffraction (XRD), vibrating sample magnetometry (VSM), and X-ray photoelectron spectroscopy (XPS). The effects of various experimental factors on the percent recovery of quercetin, including extraction time, desorption time, sample solution pH, and adsorbent amount were investigated. The Fe3O4@GO@mSiO2 strategy showed excellent stability and sensitivity for the determination of quercetin, with a suitable linear range of 20-800 µg L-1 and a detection limit of 5.2 µg L-1. The data indicate that Fe3O4@GO@mSiO2 has a specific surface area and suitable adsorption capacity for the determination of quercetin.