Magnetic Dispersive Solid-phase Extraction Research Articles

Effective magnetic nanoadsorbent based on natural carboxymethyl cellulose/polyaniline nanotube/graphene oxide for aflatoxin B1 and B2 adsorption in rice utilizing a novel synthesis method

A magnetic nanoadsorbent was prepared via a novel one-pot magnetization method by employing natural carboxymethyl cellulose (CMC), polyaniline (PANI) nanotube, and graphene oxide (GO) for the effective adsorption of aflatoxins B1 (AFB1) and B2 (AFB2) from rice samples. This synthesized adsorbent combines the multifunction of CMC, PANI, and GO and shows improved extraction performance. FT-IR, XRD, FE-SEM, VSM, and TGA analyses were used to investigate the successful synthesis of the nanocomposite. The adsorption mechanism was ascribed to π-π interactions, hydrogen bonding, and hydrophobic interactions. Under optimized conditions, the method achieved extraction recoveries ranging from 78 % to 89 %. Low limits of detection (LODs) and quantification (LOQs) were obtained in the ranges of 0.07 and 0.01 ng g−1, and 0.20 and 0.04 ng g−1 for AFB1 and B2, respectively. This method showed an acceptable precision with intra- and inter-day relative standard deviations (RSDs) of less than 15 %. Comparative studies with other adsorbents used in extraction methods such as solid phase extraction (SPE), magnetic dispersive solid phase extraction (MDSPE), and matrix solid-phase dispersion (MSPD) demonstrated that the proposed method outperforms the existing procedures; it is promising in efficient AFs monitoring in rice.

Application of magnetic AlFu MOF nanocomposite for the extraction and preconcentration of some pesticides from different distillates

This research used a magnetic AlFu nano-metal-organic framework as an adsorbent for the first time. This approach extracts and preconcentrates eight pesticides from various distillates through a two-step process: magnetic dispersive micro solid phase extraction and dispersive liquid-liquid microextraction. Initially, the nanocomposite is dispersed into a sample solution containing the pesticides and Na2SO4. The target pesticides are then adsorbed onto the nanocomposite, which is subsequently isolated from the aqueous phase using an external magnetic field. Acetonitrile is used to elute the adsorbed analytes pesticides from the nanocomposite surface. The resulting acetonitrile extract, containing the concentrated pesticides, is then mixed with a tiny amount of another solvent and injected into a NaCl solution. Centrifugation allows the organic phase, enriched with the pesticides, to settle down. An aliquot of this organic layer is then analyzed using a gas chromatography-flame ionization detector. Optimization of the procedure led to favorable performance, including good extraction recovery of the pesticides (68–98 %), significant enrichment (enrichment factors of 340–489), a wide range of detectable concentrations (2.90–1400 µg L−1), and low detection (0.15–0.88 µg L−1) and quantification limits. (0.49–2.90 µg L−1)

Starch-modified nickel ferrite nanoparticles as a magnetic nano-bio adsorbent for the extraction and determination of lead in water and Moringa oleifera samples

In this work, nickel ferrite magnetic nanoparticles were synthesized using a facile hydrothermal method. The surface modification of the prepared nanoparticles was carried out using cross-linked starch as a good stabilizer and biopolymer. The as-prepared nickel ferrite-starch nano-bio composite was characterized using numerous techniques, and introduced as a novel adsorbent. The initial experimental results indicated that the adsorbent has a good capability to extract lead ions (Pb(II)) from aqueous solutions. Hence, the adsorbent was applied for dispersive magnetic solid-phase extraction of Pb(II) before flame atomic absorption spectrometric detection. Some variables affecting the extraction efficiency such as sample volume (250.0mL), pH (6.5), type and eluent concentration (0.3molL1 nitric acid), amount of the adsorbent (200mg), extraction time (15min), and desorption time (15min) were investigated and optimized. Moreover, the adsorption capacity (35.50mgg1), stability and reusability (80 extraction/desorption cycles), and selectivity of the adsorbent towards the analyte were studied. In the optimized conditions, the linear dynamic range of the constructed calibration graph is between 0.5 and 140.0ngmL1. The limit of detection and limit of quantification of the method are 0.12 and 0.40ngmL1, respectively. The average intra-day and inter-day relative standard deviations (for n=6 and 5.0, 50.0 and 100.0ngmL1 Pb(II) concentration) are 2.02% and 3.72%, respectively. To validate the method, the certified reference material NIST SRM 1643e was analyzed, and the method was used for the pre-concentration and determination of lead ions in different sections of Moringa oleifera medicinal plant and several water samples. The acceptable relative recovery values between 98.0 and 102.7% were attained for the spiked samples, approving the ignorable matrix effect of the method.

Interaction between modified magnetic nanoparticles and human albumin: Kinetics and isotherm studies and application in protein depletion

Magnetic nanoparticles modified with tetraethyl orthosilicate (Fe3O4@TEOS) and bovine serum albumin (Fe3O4@TEOS@BSA) were evaluated as sorbent in albumin depletion from human serum samples by magnetic dispersive solid phase extraction. Characterization studies were carried out by X-ray diffraction, thermogravimetry, Fourier transform infrared spectroscopy, zeta potential, and scanning electron microscopy. Both nanoparticles also showed high thermal stability and pH-dependent surface charges. The human serum albumin adsorption protocol was optimized using a central composite rotatable design. Nanoparticle mass, pH, and albumin concentration were the most influential variables. Avrami's fractional order and Freundlich isotherm models best fitted the data for human albumin adsorption kinetic and isotherm studies for Fe3O4@TEOS and Fe3O4@TEOS@BSA, and the maximum adsorption capacities were 11.93 and 14.89 mg g−1, respectively. The protein desorption was influenced by the pH of samples and eluent volume. Electrophoresis in a polyacrylamide gel containing sodium dodecyl sulfate showed different patterns of serum protein bands when consecutive depletions were performed. The Fe3O4@TEOS showed greater affinity for HSA and efficiency in depletion. The process was versatile, and the depleted albumin proportion could be controlled by the nanoparticle masses. The proposed method is a powerful sample preparation technique for rapid, reliable, and specific depletion of albumin.

A Reliable and Straightforward Combination of vortex-assisted Dispersive Magnetic solid-phase Extraction with Direct Sorbent Sampling for Highly Sensitive Silver Determination in Water Samples Using Flame and Metal Furnace AAS.

In the present paper, the assessment of vortex-assisted dispersive magnetic solid-phase extraction using amino-functionalized mesoporous combined with direct magnetic sorbent sampling (DMSS) in flame or furnace atomic absorption spectrometry (FAAS or FF-AAS) was demonstrated for highly sensitive silver determination in water samples. The developed method showed significant enrichment factors compared to conventional pneumatic nebulization by FAAS, 607 for DMSS-FF-AAS and 114 for DMSS-FAAS. The analytical curve showed linearity in the range from 5.0 to 70.0µg L- 1 and 1.0 to 15.0µg L- 1 and limits of detection of 0.59 and 0.09µg L- 1 for DMSS-FAAS and DMSS-FF-AAS, respectively. The intra and inter-day precision evaluated as a percentage of the relative standard deviation (RSD,%) ranged from 1.89 to 4.71% for levels of 25.0 and 65.0µg L- 1. The method was applied in different kinds of water samples without matrix effects, yielding recovery values from 90 to 110%.

Synthesis of NH2-functionalized magnetic nanoparticles based on pesticide polarity for analyzing trace-level pesticides from vegetables and complex biological samples

In this study, an effective analytical approach based on targeting of 10 mid-polar pesticides residues from vegetables and biological samples using Fe3O4@SiO2-NH2 nanoparticles established by the three-step synthesis method and detected by ultrahigh-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UPLC-QTOF-MS) was proposed. Fe3O4@SiO2-NH2 nanoparticles were characterized by a size of 12–13 nm, a magnetic saturation of 43 emu/g, and sufficient NH2 groups coupled to the surface. Using the Fe3O4@SiO2-NH2, the magnetic dispersive solid phase extraction (MDSPE) for 10 mid-polar pesticides was based on targeting of 500 μL of samples (pH 7.1) vibration with 30 mg of Fe3O4@SiO2-NH2 during 10 min. This method demonstrated good recoveries (72.3–113.3 %) with relative standard deviations (RSDs) of 0.0–6.6 %, linearity ranging from 0.01 to 10 ng/mL with R2 values of 0.9945–0.9999, and limit of detection (LODs) ranging from 0.01 to 0.08 ng/mL using UPLC-QTOF-MS analysis. The proposed method was successfully applied to detect trace-level pesticide residues in real samples, such as chives, cabbage, and rat serum.

Selective solid phase extraction of folic acid from tomato as a biological source with a magnetic molecularly imprinted polymer measured by fluorescence spectroscopy

AbstractA novel magnetic molecular-imprinted polymer (MMIP) was used to selectively extract folic acid directly from real samples. Folic acid was used as template molecule, Fe3O4/SiO2-3-triethoxysilyl-propyl-acrylamide as functional monomer, azobisisobutyronitrile as initiation, ethylene glycol dimethacrylate as crosslinker agent, and acrylamide as the secondary monomer in a mixed ethanol-water solvent. The effect of different parameters on the extraction efficiency was studied, and the optimum conditions were established as follows: the concentrations of crosslinking and template were fixed at 0.05 and 0.06 g, absorption percentage was 96.5, pH was adjusted to 8, and extraction time was 8 h with a temperature of 25 °C. By examining the effect of pH, we tried to investigate the effect of the amide groups that present in MMIP and its intermolecular hydrogen interaction with folic acid. After optimising the effective parameters in polymer synthesis and adsorption rate, a magnetic imprinting dispersive solid-phase extraction method combined with fluorescence spectrophotometry at λem = 367 nm (MMIP-DSPE-FL) was constructed for sensitive determination of folic acid in tomato samples. The limit of quantification (LOQ) and limit of detection (LOD) values were 30.00 ± 0.01 μg L−1 and 10.00 ± 0.03 μg L−1, respectively, after the MMIP-DSPE preconcentration. Three tomato samples were analysed to give recoveries in the range of 80.2–81.6%, with relative standard deviation values below 0.6% (n = 3). The prepared MMIP-DSPE showed high selectivity toward folic acid, which could be used six times without changing adsorption capacity. The adsorption isotherm of the folic acid-imprinted polymer pursued the Langmuir model (RL = 0.029), and the kinetics model followed pseudo-first-order (R2 = 0.9974).

Facile synthesis of magnetic ionic covalent organic framework and dispersive magnetic solid phase extraction of aromatic amino acid oxidation products in thermally processed foods

Aromatic amino acid oxidation products (AAAOPs) are newly discovered risk substances of thermal processes. Due to its significant polarity and trace level in food matrices, there are no efficient pre-treatment methods available to enrich AAAOPs. Herein, we proposed a magnetic cationic covalent organic framework (Fe3O4@EB-iCOF) as an adsorbent for dispersive magnetic solid-phase extraction (DMSPE). Benefiting from the unique charged characteristics of Fe3O4@EB-iCOF, AAAOPs can be enriched through electrostatic interaction and π-π interactions. Under the optimal DMSPE conditions, the combined HPLC-MS/MS method demonstrated good linearity (R2 ≥ 0.990) and a low detection limit (0.11–7.5 μg·kg−1) for AAAOPs. In addition, the method was applied to real sample and obtained satisfactory recoveries (86.8 % ∼ 109.9 %). Especially, we applied this method to the detection of AAAOPs in meat samples and conducted a preliminarily study on its formation rules, which provides a reliable basis for assessing potential dietary risks.

Fast Determination of Eleven Food Additives in River Water Using C18 Functionalized Magnetic Organic Polymer Nanocomposite Followed by High-Performance Liquid Chromatography.

A novel magnetic nanomaterial with Fe3O4 as the core, PS-DVB as the shell layer, and the surface modified with C18 (C18-PS-DVB-Fe3O4) had been synthesized by seeded emulsion polymerization. C18-PS-DVB-Fe3O4 retains the advantages of the chemical stability, large porosity, and uniform morphology of organic polymers and has the magnetic properties of Fe3O4. A simple, flexible, and efficient magnetic dispersive solid phase extraction (Mag-dSPE) method for the extraction of preservatives, sweeteners, and colorants in river water was established. C18-PS-DVB-Fe3O4 was used as an adsorbent for Mag-dSPE and was coupled with high-performance liquid chromatography (HPLC) to detect 11 food additives: acesulfame, amaranth, benzoic acid, tartrazine, saccharin sodium, sorbic acid, dehydroacetic acid, sunset yellow, allura red, brilliant blue, and erythrosine. Under the optimum extraction conditions, combined with ChromCoreTMAQC18 (5 μm, 4.6 × 250 mm), 20 mmol/L ammonium acetate aqueous solution and methanol were used as mobile phases, and the detection wavelengths were 240 nm and 410 nm. The limits of detection (LODs) of 11 food additives were 0.6-3.1 μg/L with satisfactory recoveries ranging from 86.53% to 106.32%. And the material could be reused for five cycles without much sacrifice of extraction efficiency. The proposed method has been used to determine food additives in river water samples, and results demonstrate the applicability of the proposed C18-PS-DVB-Fe3O4 Mag-dSPE coupled with the HPLC method to environment monitoring analysis.

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 (1-1000µgL-1), coefficients of determination (R2≥0.997), the limits of detection (0.3-1.0µgL-1), and limit of quantification (1.0-3.0µgL-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.

Preparation of deep eutectic solvent modified magnetic graphene oxide/metal organic framework nanocomposites for the extraction of three estrogens in cosmetics.

Anovel magnetic dispersive solid phase extraction (MDSPE) procedure based on the deep eutectic solvent (DES) modified magnetic graphene oxide/metal organic frameworks nanocomposites (MGO@ZIF-8@DES) was established and used for the efficient enrichment of estradiol, estrone, and diethylstilbestrol in cosmetics (toner, lotion, and cream) for the first time. Then, thethree estrogens were separated and determined by UHPLC-UV analysis method. In order to study the features and morphology of the synthesized adsorbents, various techniques such as FT-IR, SEM, and VSM measurements were executed. The MGO@ZIF-8@DES nanocomposites combine the advantages of high adsorption capacity, adequate stability in aqueous solution, and convenient separation from the sample solution. To achieve high extraction recoveries, the Box-Behnken design and single factor experiment were applied in the experimental design. Under the optimum conditions, the method detection limits for three estrogens were 20-30ngg-1. This approach showed a good correlation coefficient (r more than 0.9998) and reasonable linearity in the range 70-10000ngg-1. The relative standard deviations for intra-day and inter-day were beneath 7.5% and 8.9%, respectively. The developed MDSPE-UHPLC-UV method was successfully used to determine three estrogens in cosmetics, and acceptable recoveries in the intervals of 83.5-95.9% were obtained. Finally, three estrogens were not detected in some cosmetic samples. In addition, the Complex GAPI tool was used to evaluate the greenness of the developed pretreatment method. The developed MDSPE-UHPLC-UV method is sensitive, accurate, rapid, and eco-friendly, which provides a promising strategy for determining hormones in different complex samples.

Fe3O4@PS-DVB microspheres modified with urea functional groups for rapid and green extraction of fluorinated aromatic carboxylic acids from tap and formation water

The present study describes the trace analysis of 23 fluorinated aromatic carboxylic acids based on the dispersive magnetic solid phase extraction (m-SPE) technique coupled with the gas chromatography coupled with mass spectrometry (GC–MS) electron ionization (EI) technique. A commercial hydrophilic-lipophilic balanced (HLB) material polystyrene divinyl benzene having urea functional groups was modified with magnetite nanoparticles and employed as a sorbent for dispersive m-SPE of fluorobenzoic acids (FBAs) from the tap and formation water samples. The extraction occurred due to π- π interaction between the aromatic ring of synthesized sorbent and the aromatic ring of FBAs, the hydrogen bond formation between the urea functional group of the sorbent and carbonyl oxygen, fluorine of the FBAs. As a result, the method was precise, rapid, reproducible, and calibrated with the coefficient of variation (R2) greater than 0.98 for all 23 compounds. The instrument detection limit (IDL) and method detection limit (MDL) were found in the range of 2.60 – 8.25 ng/mL and 0.08 – 0.28 ng/mL respectively. Extraction efficiencies were found in the range of 83.80–100 % for tap water samples and 78.41–98.92 % for formation water samples, respectively, with an enrichment factor of 33.33–66.66 and a maximum RSD of 7.07 %. The recyclability and magnetic properties of the synthesized material were also investigated, resulting in the material being reused for six cycles without impacting its performance; hence, the method offers rapid determination and high throughput analysis of FBAs. In addition, simulation studies were performed using the adsorption location tool of Material Studio, confirming the interaction sites of sorbent with FBAs. AGREE evaluated the analytical greenness of the method, and the score was found to be 0.51.

Sensitive determination of quercetin in food samples implementing magnetic dispersive solid phase extraction coupled with ion mobility spectrometry

Quercetin (QUR) is a vital flavonoid, which is found in dietary human. The quick analysis of QUR is difficult on account of utilizing complicated methods. Hence, we developed a proposed method based on ion mobility spectrometry (IMS) to evaluate the fast analysis of QUR in food samples. This analytical method combined the benefit of polypyrrole-coated magnetic dispersive solid phase extraction (MDSPE) as a sorbent phase for the QUR extraction, and also the strength of IMS for the rapid detection. Nanoparticle (NP) characterization was investigated through VSM, FT-IR, XRD, BET, and as well as FE-SEM analysis. Sample pH, amount of nanoparticles, type and volume of desorption solvent, extraction time, and desorption time as impressive parameters in MDSPE method were investigated and optimized. The calibration curve was linear in the range of 1.0–90.0 ng mL−1, with a determination coefficient (R2) of 0.9954. The limit of detection (LOD) and the limit of quantification (LOQ) for QUR were 0.31 and 1.02 ng mL−1, respectively. The RSD% of QUR through seven parallel analyses was 4.44. This analytical work was executed to quantify QUR in honey and tea samples without any derivation procedure needed. The recovery values for QUR were estimated in the range of 92.5–96.7 % using the proposed method. Also, according to the attained results from HPLC analyses, the applicability, and susceptibility of the current method was verified.

Strategic design of magnetic ionic covalent organic frameworks incorporating amino acid ionic liquids for enhanced selectivity adsorption of benzimidazoles

Advancing the frontier of material design, our innovative magnetic ionic covalent organic framework (MiCOF) masterfully overcomes traditional barriers in selective adsorption, pioneering new functionalities and surface engineering techniques to effectively target and mitigate the impacts of benzimidazoles (BZDs). In previous studies, the idea of designing magnetic nanomaterials through theoretical screening of ionic liquids has been successfully proposed. This work proposed a theoretical and practical design for MiCOFs, aimed at providing a sensitive, selective, rapid, and straightforward method for analyzing trace substances in complex biological matrices. In a gentle one-pot process, the surface of Fe3O4 was coated with covalent organic frameworks (COFs) layer, followed by the modification with amino acid ionic liquid (AAIL) through covalent radical polymerization, facilitated by the abundant unsaturated vinyl groups present. This resulted in MiCOFs (Fe3O4@COF-AAIL) with a stable structure. Compared to unmodified Fe3O4@COF, Fe3O4@COF-AAIL exhibited excellent adsorption selectivity for BZDs. This enhanced selectivity is primarily due to the strong hydrogen bonds and π-π interactions between AAIL and BZDs, aligning well with COSMO-RS theoretical screening predictions. The development of magnetic dispersive solid-phase extraction (MDSPE) enabled rapid processing of BZDs in plasma with low matrix effects (0.9–1.3). This study not only validates a robust framework for the selective separation of trace contaminants in complex biological matrices but also advances the design and application of MiCOFs, setting a new paradigm in material science that could transform the design of novel materials for specific tasks.

Synthesis of green nanosorbent from bovine serum albumin and curcumin for magnetic solid phase extraction of pesticides from food samples

For the first time, a magnetic carbon nanocomposite was synthesized using one-step hydrothermal procedure, employing bovine serum albumin, curcumin, and ferric ammonium citrate. Additionally, the application of this novel composite as an adsorbent for magnetic dispersive solid phase extraction of fungicides and pesticides from water and food samples is a unique aspect of this study. Under optimum conditions (salt concentration: 5.0% w/v, pH: 7.0, desorption solvent: ethanol, sorbent amount: 20 mg, extraction time: 20 min, desorption time: 3 min, stirring rate: 500 rpm, sample volume: 30 mL, extraction temperature: room temperature, and desorption solvent volume: 150 μL) linearity (2.5 to 1400 ng mL−1), coefficients of determination (R2 ≥ 0.997), limits of detection (0.75 to 1.5 ng mL−1), and limits of quantification (2.5 to 5.0 ng mL−1) were achieved. The method validation results showed extraction recovery ranging from 71.2% to 93.4%, and preconcentration factors ranging from 142.5 to 186.1.

Correction: Facile and rapid preparation of magnetic octadecylamine nanocomposite and its application as a capable adsorbent in magnetic dispersive solid phase extraction of some polycyclic aromatic hydrocarbons from wastewater samples

Correction: Facile and rapid preparation of magnetic octadecylamine nanocomposite and its application as a capable adsorbent in magnetic dispersive solid phase extraction of some polycyclic aromatic hydrocarbons from wastewater samples

Magnetic dispersive solid-phase extraction of clarithromycin and azithromycin by Fe3O4@ionic salt g-C3N4 adsorbent and HPLC-UV

In this study, Fe3O4@ionic salt g-C3N4 was synthesized as a new adsorbent for magnetic dispersive solid phase extraction (MDSPE) of two antibiotics (clarithromycin and azithromycin) in biological samples followed by HPLC-UV. The new nanocomposite was characterized by Fourier-transform infrared (FT-IR), field emission-scanning electronic microscope (FE-SEM), transmission electron microscope (TEM), nitrogen adsorption–desorption analysis, X-ray powder diffraction (XRD), and vibrating sample magnetometer (VSM). Box-Behnken design (BBD) and response surface methodology (RSM) were used for the optimization and design of experiments. The method had a suitable linear range (1–300 µg/L), a high coefficient of determination (R2; 0.9988 and 0.9993), and a low detection limit (0.33 and 0.42 µg/L) for clarithromycin and azithromycin, respectively. The applicability of the method was evaluated by estimating the recovery of analytes from urine and blood serum samples. Recovery of more than 90.0 % and RSDs of less than 5.2 % show the acceptable accuracy and precision of the proposed method.

Coupling Miniaturized Stir Bar Sorptive Dispersive Microextraction to Needle-Based Electrospray Ionization Emitters for Mass Spectrometry: Determination of Tetrahydrocannabinol in Human Saliva as a Proof of Concept.

Direct coupling of sample preparation with mass spectrometry (MS) can speed up analysis, enabling faster decision-making. In such combinations, where the analysis time is mainly defined by the extraction procedure, magnetic dispersive solid-phase extraction emerges as a relevant technique because of its rapid workflow. The dispersion and retrieval of the magnetic sorbent are typically uncoupled stages, thus reducing the potential simplicity. Stir bar sorptive dispersive microextraction (SBSDME) is a novel technique that integrates both stages into a single device. Its miniaturization (mSBSDME) makes it more portable and compatible with low-availability samples. This article reports the direct combination of mSBSDME and MS using a needle-based electrospray ionization (NESI) emitter as the interface. This combination is applied to determine tetrahydrocannabinol in saliva samples, a relevant societal problem if the global consumption rates of cannabis are considered. The coupling requires only the transference of the magnet (containing the sorbent and the isolated analyte) from the mSBSDME to the hub of a hypodermic needle, where the online elution occurs. The application of 5 kV on the needle forms an electrospray on its tip, transferring the ionized analyte to the MS inlet. The excellent performance of mSBSDME-NESI-MS/MS relies on the sensitivity (limits of detection as low as 2.25 ng mL-1), the precision (relative standard deviation lower than 15%), and the accuracy (relative recoveries ranged from 87 to 127%) obtained. According to the results, the mSBSDME-NESI-MS/MS technique promises faster and more efficient chemical analysis in MS-based applications.

One-step grafting of phenyl functionalized magnetic mesoporous nanocomposites for magnetic dispersive solid-phase extraction and determination of triazole fungicide residues in strawberry fruits

In this work, phenyl-SBA-15@Fe3O4 organic phenyl functional magnetic mesoporous materials were synthesized as adsorbent for magnetic dispersive solid phase extraction (M−DSPE) sample pretreatment. Seven triazole fungicides were simultaneously analyzed by high-performance liquid chromatography coupled with ultraviolet detection (HPLC-UV). The extraction recovery was 82.7 %-88.6 %, and the concentration factor was 10.6–30.8. Under the optimized experimental conditions, the regression equations of seven triazole fungicides showed a good linear relationship, the coefficient of determination r2 was 0.9993–0.9999, and the detection limit was 0.19 ∼ 1.75 μg·L-1. Six strawberry samples were randomly purchased from different places in the market, and flesh,cortex, sepal, and pulp were detected separately. The results showed that flutriafol, triadimenol and difenoconazole were detected, of which flutriafol was detected from all of them and most of them exceeded the national standard. The extraction pretreatment technology is fast and efficient, which can meet the requirements of simultaneous analysis of triazole fungicide residues in strawberries.

Magnetic iron-based metal organic framework as an adsorbent for magnetic dispersive solid-phase extraction of pyrene and phenanthrene in water samples

ABSTRACT A dispersive magnetic solid-phase extraction by means of core-shell iron-based metal-organic framework (Fe3O4- SiO2/EN@MIL-101(Fe)) nanospheres coupled with high-performance liquid chromatographic was developed for the determination of pyrene (Pyr) and phenanthrene (Phe) in water samples. Key parameters such as sorbent amount, sample volume, pH, extraction time, type and volume of elution, and desorption time were optimised by response surface methodology (RSM). Under the optimised conditions (sample volume: 5 mL, extraction time: 3 min, eluent: 3 mL acetonitrile: propanol, and desorption time: 3 min), the developed method showed a low detection and quantification limits (0.015 and 0.040 ng mL−1, respectively), good precision (< 9.8% RSD), wide linear range (0.06 - 10,000 ng mL−1, R2 > 0.99), high enrichment factors (49–57), good matrix effect (> 93.2%), high reusability (25 times), short extraction and desorption time (3 and 3 min, respectively), and high extraction recovery (96.5%). The established method was able to recover the Pyr and Phe from spiked real water samples with an extraction efficiency of 95.71% and 96.32%, respectively (RSD ≤ 9.52%).