Simple magnetization of Fe3 O4 /MIL-53(Al)-NH2 for a rapid vortex-assisted dispersive magnetic solid-phase extraction of phenol residues in water 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.

Magnetic/Zeolitic Imidazolate Framework-67 Nanocomposite for Magnetic Solid-Phase Extraction of Five Flavonoid Components from Chinese Herb Dicranopteris pedata

A magnetically functionalized Fe₃O₄@ZIF-67 metal-organic framework (MOF) was prepared by electrostatic self-assembly using magnetic Fe₃O₄ nanoparticles as the core and ZIF-67 as the shell. The composite was characterized by electron microscopy, X-ray diffraction, Fourier- transform infrared spectroscopy, and Brunauer-Emmett-Teller measurements. Magnetic solid-phase extraction (MSPE) was performed on five flavonoids from Dicranopteris pedata using Fe₃O₄@ZIF-67 as an adsorbent. The developed MSPE method was combined with high-performance liquid chromatography-ultraviolet detection to preconcentrate and separate five flavonoids (rutin, quercitrin, kaempferol-3-O-α-L-rhamnoside, quercetin, and kaempferol) from Dicranopteris pedata. The factors affecting the extraction, such as the amount of Fe₃O₄@ZIF-67 adsorbent, salt ion concentration in the sample solution, vortex time, type and amount of desorbing solvent, concentration of formic acid to acidify the desorbing solvent, and acetonitrile ratio, were optimized. The developed method showed good linearity over the concentration range of 1.09-70.0 μg∙mL^-1 for the five flavonoids, with R² values between 0.9901 and 0.9945. The limits of detection and average recoveries for the five flavonoids were in the ranges of 39.5-56.2 ng∙mL^-1 and 92.2-100.7%, respectively. The method presented herein is simple, efficient, and sensitive; it can be used for enrichment analysis of the five flavonoids in Dicranopteris pedata.

Preparation of magnetic metal-organic framework MIL-101(Fe) and its application in the extraction of anthraquinones in rhubarb

In this work, a magnetic octahedral metal organic framework (Fe₃ O₄ @NH₂ -MIL-101(Fe)) was synthesized for the magnetic solid phase extraction of three anthraquinones, including aloe-emodin, emodin, and physcion, in rhubarb. The Fe₃ O₄ @NH₂ -MIL-101(Fe) exhibited a high specific surface area of 259.2 m² /g with an average pore size of 6.0 nm and a high magnetic responsivity of 23.4 emu/g, which may be used as an adsorbent for rapid preconcentration and separation of target analytes. The main parameters for magnetic solid phase extraction of anthraquinones, including the amount of adsorbent, extraction time, extraction temperature, extraction pH, elution solvent, and elution time, were systematically optimized. The whole extraction process required a very low amount of adsorbent and a small volume of the sample. Besides, under the optimized conditions, the method showed satisfactory spiked recovery for anthraquinones in the range of 93.3%-109.1%, and the LODs were 1.7-3.4 ng/mL. The RSDs for intra- and inter- day precision were 0.2%-1.3% and 0.2%-0.6%, respectively. The experimental results indicate that the developed method is feasible for the analysis of anthraquinones in rhubarb. This article is protected by copyright. All rights reserved.

Rapid quantitation of three synthetic cathinones in urine by magnetic dispersive solid-phase extraction combined with DART-HRMS

For the rapid quantitation of three synthetic cathinones, namely 1-(4-chlorophenyl)-2-(1-pyrrolidinyl)pentan-1-one (4-Cl-α-PVP), 1-(4-methylphenyl)-2-(methylamino)pentan-1-one (4-MPD), and 1-(5,6,7,8-tetrahydronaphthalen-2-yl)-2-(1-pyrrolidinyl)pentan-1-one (β-TH-naphyrone), in urine, a new method was established using magnetic dispersive solid-phase extraction (MDSPE) combined with direct analysis in real time and high-resolution mass spectrometry (DART-HRMS). Methcathinone-D3 and proadifen (SKF525A) were used as the internal standards. Hydrophobic magnetic adsorbents were used and consisted of hydrophobic functional group (divinylbenzene) and hydrophilic functional group (vinylpyrrolidone) at a ratio of 3 : 1, and NaH₂PO₄//NaOH buffer (0.2 M, pH 7) was used in MDSPE. Detection was conducted by DART-HRMS in less than 1 min. For 4-Cl-α-PVP, 4-MPD and β-TH-Naphyrone, the limits of detection were 0.1 ng mL^-1, 0.05 ng mL^-1 and 0.1 ng mL^-1, and the linear ranges were 0.5-100 ng mL^-1, 0.2-100 ng mL^-1 and 0.2-100 ng mL^-1, respectively. The correlation coefficients were all greater than 0.99. The precision and deviation of accuracy were all within ±15%, and the stability of the samples was high under various conditions. The method was successfully applied to detect 4-Cl-α-PVP, 4-MPD and β-TH-naphyrone in rat urine after subcutaneous administration. In summary, a fast and convenient detection method was established, providing new and effective technical support for the rapid quantitation of three synthetic cathinones (4-Cl-α-PVP, 4-MPD and β-TH-Naphyrone) for forensic purposes.

Amido-Functionalized Magnetic Metal-Organic Frameworks Adsorbent for the Removal of Bisphenol A and Tetracycline

In this paper, amido-functionalized MOFs with core/shell magnetic particles (Fe₃O₄@MIL-53(Al)-NH₂) was prepared by the solvothermal method and characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), Fourier transform infrared (FT-IR), Vibrating Sample Magnetometer (VSM) and UV/VIS spectrophotometer. The influence of different factors on the adsorption effect of the pollutant, including adsorbent amounts, adsorption time, ionic strength and pH, were explored. It was found that the amine-decorated Fe₃O₄@MIL-53(Al)-NH₂ were efficient for removal of contaminant, with the adsorption capacity for bisphenol A (234.1 mg/g) and tetracycline (84.8 mg/g) under the optimized conditions. The adsorption kinetics and the equilibrium adsorption data indicated that the adsorption process of BPA and TC was more compatible with the pseudo-second-order kinetic model and the Langmuir model, respectively. The thermodynamic values show the adsorption of the mentioned contaminant was spontaneous and endothermic. Moreover, the Fe₃O₄@MIL-53(Al)-NH₂ adsorbent had good regeneration and reusability capacity after five cyclic utilization. All these results show Fe₃O₄@MIL-53(Al)-NH₂ adsorbent could be a potential candidate for future water purification.

[Recent advance of new sample preparation materials in the analysis and detection of environmental pollutants]

针对复杂样品的分析和痕量目标物的检测,样品前处理是必不可少的,高效的样品前处理技术不仅可以去除或减小样品基质干扰而且能够实现分析物的富集,提高分析检测的准确性和灵敏度。近年来,固相萃取、磁分散固相萃取、枪头固相萃取、搅拌棒萃取、固相微萃取等高效的样品前处理技术已在环境污染物分析检测中获得广泛关注,萃取效率主要取决于萃取材料,所以新型的高效萃取材料一直是样品前处理研究领域的重要发展方向。该文总结和讨论了近年来新型样品前处理材料在环境污染物分析检测中的研究进展,主要聚焦在石墨烯、氧化石墨烯、碳纳米管、无机气凝胶、有机气凝胶、三嗪基功能材料、三嗪基聚合物、分子印迹聚合物、共价有机框架材料、金属有机框架材料以及它们的功能化萃取材料等。这些材料已经被应用于环境样品中不同类别污染物的萃取富集,如重金属离子、多环芳烃、塑化剂、烷烃、苯酚、氯酚、氯苯、多溴联苯醚、全氟磺酸、全氟羧酸、雌激素、药物残留、农药残留等。这些样品前处理材料具有高的表面积、大量的吸附位点,并涉及多种萃取机理如π-π、静电、疏水、亲水、氢键、卤键等相互作用。基于这些萃取材料的多种样品前处理技术与各类检测方法如色谱、质谱、原子吸收光谱、荧光光谱、离子迁移谱等相结合,已广泛应用于环境污染物的高灵敏分析检测。最后,该文总结了样品前处理发展中存在的问题,并展望了其未来在环境分析中的发展趋势。

Glutathione-stabilized Fe3 O4 nanoparticles as the sorbent for magnetic solid-phase extraction of diazepam and sertraline from urine samples through quantitation via high-performance liquid chromatography

The synthesis and application of glutathione-coated magnetic nanocomposite were introduced with the purpose of developing a stable, cheap, operationally convenient, simple, fast, sensitive, and selective device for the microextraction of diazepam and sertraline for the first time. The prepared glutathione@Fe₃ O₄ nanocomposite was used as the sorbent in the form of magnetic solid-phase extraction. Afterward, the extracted analytes were desorbed by organic solvent and analyzed by high-performance liquid chromatography-ultraviolet detection. Several influential variables such as desorption time, desorption volume, sample pH, extraction time, and sorbent amount were screened through Plackett-Burman design and then optimized via Box-Behnken design. The obtained results showed that the above-mentioned method enjoys a good linear range (0.2-500 μg/L) with the coefficient of determination higher than 0.9927, low limits of determination (0.07-0.24 μg/L), acceptable limits of quantification (0.22-0.93 μg/L), good enrichment factors (128 and 153), and good spiking recoveries (95-105%) for diazepam and sertraline under the obtained optimized condition. Analyzing the real samples results in the confirmation of the presented method and it can be applied for the analysis of various organic compounds in biological samples.