Magnetic molecularly imprinted polymers based on eco-friendly deep eutectic solvent for recognition and extraction of three glucocorticoids in lotion

A novel deep eutectic solvent modified magnetic covalent organic framework for the selective separation and determination of trace copper ion in medicinal plants and environmental samples

Development of magnetic dispersive micro-solid phase extraction based on magnetic adipic acid nanoparticles and deep eutectic solvents for the isolation and pre-concentration of phenolic compounds in fruit juice samples prior to determination by HPLC-UV

An automated magnetic dispersive micro-solid phase extraction in a fluidized reactor for the determination of fluoroquinolones in baby food samples

This study describes the synthesis and application of a magnetic amino-functionalized hollow silica-titania microsphere as a new sorbent for magnetic dispersive micro-solid phase extraction of selected pesticides in coffee bean samples. The sorbent was fully characterized by Fourier-transform infrared spectroscopy, field emission scanning electron microscopy, transition electron microscopy, energy-dispersive X-ray spectroscopy, and vibrating sample magnetometry techniques. Significant extraction parameters affecting the proposed method, such as extraction time, sorbent amount, sample solution pH, salt amount, and desorption conditions (desorption solvent and time) were investigated and optimized. All the figures of merits were validated in coffee bean samples under the matrix-matched calibration method. Linear dynamic ranges were 5-250µg/kg with the determination coefficients (R2 )>0.9980. The limits of detection for the pesticides of chlorpyrifos, malathion, hexaconazole, and atrazine were 1.42, 1.43, 1.35, and 1.33µg/kg, respectively. Finally, the method was successfully applied for the determination of the pesticides in green and roasted coffee bean samples, and the obtained recoveries were in the range of 74-113% for spiked samples. The prepared sorbent could be used for the magnetic dispersive micro-solid phase extraction of pesticides in the plant-derived food matrix.

A selective and sensitive magnetic dispersive solid-phase microextraction (MDSPME) coupled with gas chromatography-mass spectrometry was developed for extraction and determination of organophosphorus pesticides (Sevin, Fenitrothion, Malathion, Parathion, and Diazinon) in fruit juice and real water samples. Zero valent Fe-reduced graphene oxide quantum dots (rGOQDs@ Fe) as a new and effective sorbent were prepared and applied for extraction of organophosphorus pesticides using MDSPME method. In order to study the performance of this new sorbent, the ability of rGOQDs@ Fe was compared with graphene oxide and magnetic graphene oxide nanocomposite by recovery experiments of the organophosphorus pesticides. Several affecting parameters in the microextraction procedure, including pH of donor phase, donor phase volume, stirring rate, extraction time, and desorption conditions such as the type and volume of solvents and desorption time were thoroughly investigated and optimized. Under the optimal conditions, the method showed a wide linear dynamic range with R-square between 0.9959 and 0.9991. The limit of detections, the intraday and interday relative standard deviations (n = 5) were less than 0.07 ngmL-1, 4.7, and 8.6%, respectively. The method was successfully applied for extraction and determination of organophosphorus pesticides in real water samples (well, river and tap water) and fruit juice samples (apple and grape juice). The obtained relative recoveries were in the range of 82.9%-113.2% with RSD percentages of less than 5.8% for all the real samples.

Simultaneous extraction and preconcentration of three beta (β)-blockers in biological samples with an efficient magnetic dispersive micro-solid phase extraction procedure employing in situ sorbent modification

A compartmental model was used to describe the pharmacokinetics of dexamethasone (DXM) and changes in the plasma concentration of endogenous cortisone (COR) and hydrocortisone (HYD) following intravenous (i.v.) administration of DXM (0.05 mg/kg) in horses. Quantification of DXM, COR and HYD in equine plasma was achieved using liquid chromatography interfaced with triple spray quadrupole quantum tandem mass spectrometry (LC/TSQ-MS/MS). The median alpha (t(1/2alpha)), beta (t(1/2beta)), and gamma (t(1/2gamma)) half-lives were 0.33, 2.2, and 10.7 h respectively. The area under the DXM plasma concentration curve (AUC) was 113.5 ng.h/mL. At 72 h post-DXM administration, the plasma concentration of DXM in all horses was below the level of quantification (100 pg/mL). The baseline plasma concentration of COR was 3.5 +/- 0.69 ng/mL and declined significantly (P < 0.02) to 2.9 +/- 0.86 ng/mL at 1 h. The nadir in COR plasma concentration was 0.65 +/- 0.12 ng/mL at 28.8 +/- 9.0 h, and the DXM plasma concentration was 0.19 +/- 0.13 ng/mL. COR concentration returned to baseline at 96 h. Baseline plasma concentration of HYD was 58.8 +/- 11.7 ng/mL and declined significantly (P < 0.001) to 41.1 +/- 14.9 ng/mL at 1 h following DXM administration but recovered to baseline at 96 h. The sensitivity of LC/TSQ-MS/MS allowed complete description of the pharmacokinetics of DXM and its effect on plasma concentrations of both COR and HYD.

Magnetic graphene oxide/lanthanum phosphate nanocomposite (MGO@LaP) was synthesized and used as an efficient adsorbent for magnetic dispersive microsolid-phase extraction (MD-µ-SPE) of pesticides before gas chromatography–electron capture detector (GC–ECD) analysis. The adsorbent was thoroughly characterized with scanning electron microscopy, vibrating sample magnetometer, energy-dispersive X-ray spectroscopy, and Fourier transform infrared spectroscopy. Optimized extraction conditions were investigated concerning extraction time, adsorbent amount, sample pH, and salt amount as well as desorption conditions (type and volume of desorption solvent and desorption time). Under the optimal conditions, the method demonstrated good linearity (3–1500 µg L−1) with satisfactory determination coefficients of > 0.997 and low detection limits for both chlorpyrifos (0.67 µg L−1) and hexaconazole (0.89 µg L−1). Finally, the method showed high analyte relative recoveries in the range of 78–120% for the determination of the selected pesticides in water and fruit juice samples.

Ultrasonic assisted magnetic dispersive solid phase microextraction for preconcentration of two nonsteroidal anti-inflammatory drugs in real water, biological and milk samples employing an experimental design

Development of magnetic dispersive micro-solid phase extraction of four phenolic compounds from food samples based on magnetic chitosan nanoparticles and a deep eutectic supramolecular solvent

The combination of two microextraction techniques (dispersive liquid-liquid microextraction [DLLME] and magnetic dispersive microsolid phase extraction [MDMSPE]) was developed and reported for atrazine and simazine preconcentration from wastewater samples. The proposal methodology involved the use of magnetite supports functionalized with different alkyl or phenyl groups. The magnetic adsorbents were synthesized by the solvothermal method assisted by microwave, characterized, and used in the sample preconcentration of atrazine and simazine. The method validation included parameters such as the wastewater matrix effect, repeatability, and recovery. The analyte separation and quantification were performed by high-performance liquid chromatography with ultraviolet detection (HPLC-DAD). Parameters, such as the polarity and mass of magnetic solids and pH, were evaluated to provide better extraction performance. The highest recoveries (> 95%) were obtained with 50mg of the phenyl group support (CS2) at pH5, using 5mL of the sample and carbon tetrachloride and methanol, as extraction and dispersive solvents, respectively. The lowest limits of detection (LOD) achieved were 13.16 and 13.86ngL-1, and the limits of quantification (LOQ) were 43.89 and 46.19ngL-1 for simazine and atrazine, respectively, with repeatability (expressed as %RSD) below 5% in all cases. The developed method is simple, easy, and low cost for the analysis of two herbicides potentially dangerous for environmental and human health. Graphical abstract.

Application of magnetic nanoparticles modified with poly(8-hydroxyquinoline) as a nanosorbent for magnetic dispersive micro-solid phase extraction of copper in vegetable, water, and soil samples

Switchable-hydrophilicity solvent liquid–liquid microextraction prior to magnetic nanoparticle-based dispersive solid-phase microextraction for spectrophotometric determination of erythrosine in food and other samples

A magnetic molecularly imprinted polymer (MMIP) was successfully synthesized and applied as the sorbent in the magnetic dispersive solid-phase microextraction (MDSPME) to separate and preconcentrate diazinon from real samples prior to its determination by high-performance liquid chromatography with ultraviolet detector (HPLC-UV). The MMIP was prepared by one-step surface imprinting technique using precipitation polymerization method without any use of surfactants or stabilizers. The functionalized Fe3O4 nanoparticles were used as the magnetic supporter, diazinon as the template, methacrylic acid (MAA) as the functional monomer, and ethylene glycol dimethacrylate (EGDMA) as the cross-linker. The synthesized MMIP was characterized by Fourier transform infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM), X-ray diffraction (XRD) spectroscopy, and Brunauer–Emmett–Teller (BET) analysis. The selectivity study demonstrated that the MMIP had high affinity toward diazinon compared to other organophosphates (fenitrothion and chlorpyrifos). Various parameters affecting the efficiency of extraction such as sorption and desorption time, amount of sorbent, type and volume of eluting solvent, and pH were investigated and optimized. Under the optimum conditions, the calibration graph was linear over the range of 0.07–30.0 μg L−1 with the limit of detection of 0.02 μg L−1. The relative standard deviations (RSDs) at the 0.1 and 10.0 μg L−1 levels of diazinon (n = 5) were 3.8 and 2.0 %, respectively. The proposed method was successfully applied to the determination of trace amount of diazinon in tomato, cucumber, apple, and well water samples.

Magnetic dispersive micro solid-phase extraction for trace mercury pre-concentration and determination in water, hemodialysis solution and fish samples