Fe3O4@ionic liquid@methyl orange nanoparticles as a novel nano-adsorbent for magnetic solid-phase extraction of polycyclic aromatic hydrocarbons in environmental water samples

Fabrication of magnetite nanomaterials employing novel ionic liquids for efficient oil spill cleanup

The oil spill represents one of the most important pollution sources for marine environments, that occurs due to tanker collisions, ship accidents, and platforms. Several techniques are used for treating oil spill disasters including chemical, physical, and biochemical. The use of chemicals, magnetite nanomaterials (MNMs) in particular, is one of the most applied techniques used for oil spill remediation due to their low cost, fast remediation, and reusability. This work aims to synthesize and use new ionic liquids (ILs) for the modification of MNMs surfaces to enhance their performance for crude oil uptake. For that, octadecylamine (OA) was reacted with epichlorohydrin (EH), followed by reaction with either diethylenetriamine (DT), or tetraethylenepentamine (TP) to obtain corresponding amines, OADT, and OATP, respectively. The produced amines were quaternized using acetic acid (AA) forming corresponding ILs, OADT-IL, and OATP-IL. The obtained ILs, OADT-IL, and OATP-IL were applied for modification of magnetite nanomaterials (MNMs) surface to obtain the surface-modified MNMs, DT-MNMs, and TP-MNMs, respectively. The surface-modified MNMs were characterized using different techniques including Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), vibrating sample magnetometer (VSM), and contact angle. The efficacy of DT-MNMs, and TP-MNMs for heavy crude oil uptake (EMU) was evaluated. Further, the factors affecting on the crude oil uptake including MNMs: heavy crude oil ratio, and contact time were also evaluated. The data exhibited that, the EMU relatively declined as the ratio of DT-MNMs, and TP-MNMs decreased. Even at low MNMs:crude oil ratio (1:50), DT-MNMs, and TP-MNMs displayed EMU 87%, and 90%, respectively, which means 1 g of either DT-MNMs, or TP-MNMs can uptake 45 g, or 43.5 g, respectively. These values are high as compared with other studies that reported the use of MNMs for oil spill cleanup. Furthermore, the data indicated that the EMU increased as the contact time increased, and reached maximum EMU of 98% for both MNMs samples after 10 min.

Ionic liquid-based magnetic nanoparticles for magnetic dispersive solid-phase extraction: A review

Due to their highly tunable nature and outstanding physicochemical properties, ionic liquids (ILs) have been widely reported for use in the synthesis of multitudinous magnetic nanoparticles (MNPs). IL-based magnetic nanoparticles (IL-MNPs) have great potential in magnetic dispersive solid-phase extraction (MDSPE). At present, IL-MNPs have been successfully applied in the pretreatment of MDSPE samples from medicines, pesticides, veterinary drugs, heavy metals, dyes, additives, and proteins in agricultural products, foods and beverages, environmental water, and biological samples. In this review, the preparation of IL-MNPs and their application in MDSPE are comprehensively summarized. The structural characteristics of the introduced ILs used to prepare the IL-MNPs and the synthetic routes employed to obtain the IL-MNPs are described, including physical coating and chemical bonding methods. The IL-MNPs are then classified and described according to different modified materials, including silica-based materials, carbon-based materials, metal-organic frameworks, molecularly imprinted polymers and other interesting large/small molecules. Finally, the research prospects and development directions of IL-MNPs in the context of MDSPE are further identified.

Magnetic covalent organic framework nanocomposites as a new adsorbent for the determination of polycyclic aromatic hydrocarbons in water and food samples

A magnetic covalent organic framework nanocomposite (Fe₃O₄@COF(Tp-NDA)) was synthesized via a solvothermal method, used as a magnetic adsorbent for the extraction of polycyclic aromatic hydrocarbons (PAHs) from lake water, tea, coffee, and fried chicken, and detected using a high performance liquid chromatography-ultraviolet detector. The synthesized magnetic adsorbent was characterized via transmission electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy, N₂ adsorption-desorption isotherm analysis and vibrating sample magnetometry. Parameters that affected the extraction conditions and desorption conditions were optimized. Adsorption equilibrium could be attained within 3 min. The prepared magnetic material could be reused 10 times. The limits of detection and quantification were 0.05-0.25 μg L^-1 and 0.17-0.83 μg L^-1, respectively. The recovery was 74.6-101.8% with a relative standard deviation of below 4.2%. The method was successfully used to detect PAHs in various samples.

Novel materials for dispersive (micro) solid-phase extraction of polycyclic aromatic hydrocarbons in environmental water samples: A review

Polycyclic aromatic hydrocarbons are hazardous environmental pollutants that possess mutagenic and carcinogenic properties. Generally, the concentrations of PAHs in environmental water samples are very low, and it is challenging to detect such levels directly by the analytical instrumentation. Thus, the extraction of PAHs using suitable extraction methodology is required for sample cleanup and analyte enrichment. Dispersive solid-phase extraction has several advantages over conventional approaches for the extraction of PAHs from environmental water samples. In this article, we critically evaluate the role of different nano and micro sorbent materials employed in the extraction of PAHs. Carbon-based nanomaterials, metal-organic frameworks, polymeric nanocomposites, ionic-liquid based composites, and silica-based materials are explicitly covered. This review also provides insight on functional components of all types of sorbents and their way of interaction with PAHs. The factors affecting the dispersive (micro) solid phase extraction of PAHs such as the design of the sorbent, the ratio of functional material to magnetic core, sample volume, amount of sorbent, extraction and desorption times, desorption solvent and its volume, salt addition, and sample pH are critically appraised. Finally, a brief account on the accomplishments, limitations, and challenges associated with such methods is provided.

Adsorption onto MWCNTs Coupled with Cloud Point Extraction for Dye Removal from Aqueous Solutions: Optimization by Experimental Design

AIMS

The main aim of the study was to examine the feasibility and benefits of adsorption onto multi-walled carbon nanotubes (MWCNTs) coupled with cloud point extraction (CPE) for the removal of Rhodamine B (RB) from aqueous solutions.

BACKGROUND

MWCNTs offer the particular features of the ideal adsorbents for the organic dyes such as hollow tubular structure and specific surface area. Nevertheless, they suffer from the drawbacks of low dispersion in the aqueous solutions and separation inconvenience from the media. Cloud point extraction, combined with the adsorption onto MWCNTs can be a promising method to overcome the problems.

OBJECTIVE

In the study, adsorption onto MWCNTs coupled with CPE was applied for RB removal from aqueous solutions. The process was optimized by the response surface modeling method. Moreover, the applicability of the proposed method in the real sample analyses was investigated.

METHODS

MWCNTs were used as adsorbent and Triton X-100 (TX-100) as the nonionic surfactant for CPE process. The experiments were carried out based on a Box-Behnken design (BBD) with the input variables of MWCNTs dosage (0.6-1.2 mg), solution pH (3-9), clouding time (20-40 min) and TX-100 concentration (10-20 v/v%) using 5 mg L-1 RB solutions.

RESULT

Regression analyses resulted in a statistically significant quadratic model (R2=0.9718, F=24.96, p<0.0001) by which the optimum levels of the variables were predicted as: MWCNTs dosage of 0.7 mg, pH=3, clouding time of 39.9 minutes and TX-100 concentration of 19.91% (v/v). The predicted conditions were experimentally validated by achieving an RB removal of 94.24%.

CONCLUSION

Based on the results, the combination of the environmentally friendly technique of CPE with adsorption onto MWCNTs allows the efficient removal of RB from water samples and the method can be effectively optimized by the response surface modeling.

Recent Advances in the Extraction of Polycyclic Aromatic Hydrocarbons from Environmental Samples

Polycyclic aromatic hydrocarbons (PAHs) comprise a group of chemical compounds consisting of two or more fused benzene rings. PAHs exhibit hydrophobicity and low water solubility, while some of their members are toxic substances resistant to degradation. Due to their low levels in environmental matrices, a preconcentration step is usually required for their determination. Nowadays, there is a wide variety of sample preparation techniques, including micro-extraction techniques (e.g., solid-phase microextraction and liquid phase microextraction) and miniaturized extraction techniques (e.g., dispersive solid-phase extraction, magnetic solid-phase extraction, stir bar sorptive extraction, fabric phase sorptive extraction etc.). Compared to the conventional sample preparation techniques, these novel techniques show some benefits, including reduced organic solvent consumption, while they are time and cost efficient. A plethora of adsorbents, such as metal-organic frameworks, carbon-based materials and molecularly imprinted polymers, have been successfully coupled with a wide variety of extraction techniques. This review focuses on the recent advances in the extraction techniques of PAHs from environmental matrices, utilizing novel sample preparation approaches and adsorbents.

Critical review of micro-extraction techniques used in the determination of polycyclic aromatic hydrocarbons in biological, environmental and food samples

Polycyclic Aromatic Hydrocarbons (PAHs) are ubiquitous environmental contaminants and their accurate determination is very important to human health and environment safety. In this review, sorptive-based micro-extraction techniques [such as Solid-Phase Micro-extraction (SPME), Stir Bar Sorptive Extraction (SBSE), Micro-extraction in Packed Sorbent (MEPS)] and solvent-based micro-extraction [Membrane-Mediated Liquid-Phase Micro-extraction (MM-LPME), Dispersive Liquid-Liquid Micro-extraction (DLLME), and Single Drop Micro-extraction (SDME)] developed for quantification of PAHs in environmental, biological and food samples are reviewed. Moreover, recent micro-extraction techniques that have been coupled with other sample extraction strategies are also briefly discussed. The main objectives of these micro-extraction techniques are to perform extraction, pre-concentration and clean up together as one step, and the reduction of the analysis time, cost and solvent following the green chemistry guidelines.

Magnetic Solid-Phase Extraction of Pyrethroid Pesticides from Environmental Water Samples Using Deep Eutectic Solvent-type Surfactant Modified Magnetic Zeolitic Imidazolate Framework-8

A simple, sensitive and effective magnetic solid-phase extraction (MSPE) technique was developed for the extraction of pyrethroid pesticides from environmental water samples, followed by gas chromatography tandem triple quadrupole mass spectrometry determination. An adsorbent of magnetic zeolitic imidazolate framework-8@deep eutectic solvent (M-ZIF-8@DES) was prepared using deep eutectic solvent coated on the surface of M-ZIF-8. The features of M-ZIF-8@DES were confirmed by material characterizations, and the results indicated that M-ZIF-8@DES has a good magnetism (61.3 emu g-1), a decent surface area (96.83 m2 g-1) and pore volume (0.292 mL g-1). Single factor experiments were carried out to investigate the effect of different conditions on the performance of MSPE. Under the optimal conditions, the developed method performs good linearity (R2 ≥ 0.9916) in the concentration range of 1-500 μg L-1. The limits of detection were in the range of 0.05-0.21 μg L-1 (signal/noise = 3/1). The intraday relative standard deviation (RSD) and interday RSD were less than 9.40%. Finally, the proposed technique was applied for the determination of pyrethroid pesticides in environmental water samples. This work shows the potential of DES-modified metal-organic frameworks for different sample pretreatment techniques.

Organic Analysis of Environmental Samples Using Liquid Chromatography with Diode Array and Fluorescence Detectors: An Overview

This overview is focused to provide an useful guide of the families of organic pollutants that can be determined by liquid chromatography operating in reverse phase and ultraviolet/fluorescence detection. Eight families have been classified as the main groups to be considered: carbonyls, carboxyls, aromatics, phenols, phthalates, isocyanates, pesticides and emerging. The references have been selected based on analytical methods used in the environmental field, including both the well-established procedures and those more recently developed.

A high efficient adsorbent for plant growth regulators based on ionic liquid and β-cyclodextrin functionalized magnetic graphene oxide

Four types of ionic liquids which composed of cation with imidazole ring and anion with benzene, naphthalene, anthraquinone and naphthoquinone ring were prepared and named VOIm⁺BenSO₃^-, VOIm⁺NapSO₃^-, VOIm⁺AQSO₃^- and VOIm⁺NQSO₃^-, respectively. Then, ionic liquids and β-cyclodextrin functionalized magnetic graphene oxide materials were firstly synthesized for the extraction of 23 plant growth regulators in vegetable samples. The synthesized materials anticipated the unique properties of ionic liquids, β-cyclodextrin, graphene oxide and Fe₃O₄@SiO₂, including high surface area, high supramolecular recognition capability, superparamagnetism and large delocalized π-electron system, which were successfully characterized. Among four kinds of ionic liquids functionalized adsorbents, the VOIm⁺AQSO₃^- modified material exhibited high adsorption capability to 7 plant growth regulators compared with Fe₃O₄@SiO₂/GO/β-CD, Fe₃O₄@SiO₂/GO and other three types of ionic liquids based adsorbents. Parameters that could affect the recoveries of 7 plant growth regulators were investigated, such as mass ratio of Fe₃O₄@SiO₂/GO/β-CD to ionic liquids, salt concentration, pH, amount of adsorbent, extraction time and desorption solvent. Under the optimal condition, the magnetic solid phase extraction method using VOIm⁺AQSO₃^- and β-cyclodextrin functionalized magnetic graphene oxide material (Fe₃O₄@SiO₂/GO/β-CD/IL) as adsorbent was developed and coupled with ultra-high performance liquid chromatography-triple quadrupole linear ion trap mass spectrometry for the determination of 7 plant growth regulators in vegetable samples. Validation results showed that the limit of detection and limit of quantitation were in the range of 0.01-0.18 μg/kg and 0.03-0.58 μg/kg, respectively. The satisfactory linearities were acquired in the concentration of 2-50 μg/kg with the correlation coefficients higher than 0.9982. Taken together, the synthesized Fe₃O₄@SiO₂/GO/β-CD/IL was a highly effective magnetic solid phase extraction adsorbent for the enrichment of trace level of plant growth regulators in vegetable samples.

Investigation of nanoscale zerovalent iron-based magnetic and thermal dual-responsive composite materials for the removal and detection of phenols

In this study, well-defined magnetic and thermal dual-responsive nanomaterials were synthesized, which contained ultrafine core-shell Fe@SiO₂ nanoparticles as magnetic core and poly(N-isopropylacrylamide) (PNIPAM) as thermosensitive outer shell. The fabricated nanoparticles were characterized and investigated for the adsorption of four phenolic compounds, including bisphenol A (BPA), tetrabromobisphenol A (TBBPA), 4-tert-octylphenol (4-OP) and 4-n-nonylphenol (4-NP). The experimental results demonstrated that the excellent adsorption rates were attributed to hydrophobic effect, hydrogen-bonding interaction, and electrostatic attraction. The adsorption process followed pseudo-second-order kinetics model and nonlinear isotherms, indicating heterogeneous adsorption process. The adsorption efficiency of 4-NP using Fe@SiO₂@PNIPAM was more than 90% under optimized condition within 2 h. The determined maximum adsorption amounts of BPA, TBBPA, 4-OP and 4-NP were 2.43, 6.83, 24.75, and 49.34 mg g^-1, respectively. Meanwhile, a magnetic solid phase extraction (MSPE) method with Fe@SiO₂@PNIPAM was established to determine these four compounds simultaneously. Under the optimal conditions, the linearity ranges were in the range of 2-200, 2-300, 2-100 and 2-100 μg L^-1 for BPA, 4-OP, TBBPA, and 4-NP, respectively, and the detection limits were in the range of 0.58-0.76 μg L^-1, respectively. The applicability of the proposed method was evaluated by analyzing three fresh water samples, and satisfactory spiked recoveries in the range 70.9-119.9% were achieved. It was proved that these adsorbents could be easily collected and recycled owing to the appropriate magnetism. The results also demonstrated that the as-prepared adsorbents had promising potential in the enrichment and analysis of detrimental organic pollutants from water.

Ionic liquid-based dispersive liquid-liquid microextraction combined with functionalized magnetic nanoparticle solid-phase extraction for determination of industrial dyes in water

N-butyl pyridinium bis((trifluoromethyl)sulfonyl)imide ([Hpy]NTf₂) functionalized core/shell magnetic nanoparticles (MNPs, Fe₃O₄@SiO₂@[Hpy]NTf₂)) were prepared and applied as an adsorbent for magnetic solid phase extraction (MSPE) of three commonly used industrial dyes including malachite green, crystal violet and methylene blue. Extraction solution was mixed with 100 mg extraction material of Fe₃O₄@SiO₂@[Hpy]NTf₂, and 1 mL of acetonitrile was used to elute target analytes for further extraction and purification. [Hpy]NTf₂ was used as extraction solution, and 500 μL methanol was selected as dispersive solvent in ionic liquid (IL) dispersive liquid–liquid microextraction (DLLME) method. After sonication for 5 min and centrifugation at 447 g for 10 min, 20 μL of sedimented phase was injected into HPLC-UV system. The limit of detection (LOD) and limit of quantification (LOQ) of current method were 0.03 and 0.16 μg·L⁻¹, respectively, which indicated the sensitivity was comparable or even superior to other reported methods. The relative recoveries of the target analytes ranged from 86.1% to 100.3% with relative standard deviations between 0.3% and 4.5%. The developed method has been successfully applied to determine the level of three industrial dyes in different water samples.

Determination of volatile polycyclic aromatic hydrocarbons in waters using headspace solid-phase microextraction with a benzyl-functionalized crosslinked polymeric ionic liquid coating

A benzyl-functionalized crosslinked polymeric ionic liquid (PIL), produced through the co-polymerization of the 1-vinylbenzyl-3-hexadecylimidazolium bis[(trifluoromethyl)sulfonyl]imide (VBHDIM-NTf₂) ionic liquid (IL) monomer and 1,12-di(3-vinylbenzylimidazolium)dodecane bis[(trifluoromethyl)sulfonyl]imide ((DVBIM)₂C_12-2NTf₂) IL crosslinker, was successfully used as a sorbent coating in headspace solid-phase microextraction (SPME) coupled to gas chromatography (GC) with flame-ionization detection (FID) to determine seven volatile polycyclic aromatic hydrocarbons (PAHs) in environmental water samples. Optimum extraction conditions for the PAHs when using the novel sorbent include an extraction temperature of 50°C, an ionic strength content adjusted with 30% (w/v) NaCl in the aqueous sample, and an extraction time of 60 min. The extraction performance of the crosslinked PIL fiber was compared to the SPME commercial coating polydimethylsiloxane fiber. The calibration ranges of the studied PAHs were linear in the range of 0.02-20 µg L^-1 for the crosslinked PIL fiber. The accuracy of the proposed method was demonstrated by examining the spiked recoveries of seven PAHs which produced values ranging from 67.2% to 130% (for river- and seawater samples), and precision values lower than 9.4% for a spiked level of 1 µg L^-1, and detection limits between 0.01 and 0.04 µg L^-1, which supports the sensitivity of the method using GC-FID.

Solid phase extraction of trace amounts of cadmium(II) ions in water and food samples using iron magnetite nanoparticles modified by sodium dodecyl sulfate and 2-mercaptobenzothiazole

A new, simple and rapid method for solid phase extraction and preconcentration of trace amounts of cadmium ions using 2-mercaptobenzothiazole/sodium dodecyl sulfate immobilized on magnetite nanoparticles (MBT-SDS-MNPs) was proposed. The method is based on the extraction of cadmium ions via complexation with MBT immobilized on SDS-coated MNPs and their determination by flame atomic absorption spectrometry. The effects of different parameters - pH; eluent type, concentration and volume; amounts of salt and adsorbent; contact time and interfering ions - on the adsorption of cadmium ions were studied. Under optimized conditions, the calibration curve was linear in the range of 10-5,000 μg L^-1. Detection limit and relative standard deviation of the proposed method were 0.009 μg L^-1 and 2.2%, respectively. The adsorption data were analyzed by Langmuir and Freundlich isotherm models and a maximum adsorption amount of 24.80 mg g^-1, a Langmuir adsorption equilibrium constant (b) of 4.62 and Freundlich constants K_f and n of 6.075 mg^1-1/n L^1/n g^-1 and 2.391, respectively, were obtained. Finally, this adsorbent was successfully used for extraction of cadmium from water and food samples.

Synthesis and application of monodisperse hydrophobic magnetite nanoparticles as an oil spill collector using an ionic liquid

In this work, a new facile green method was proposed to prepare monodisperse magnetic nanoparticles at room temperature with controlled shape and size.

Oxidative desulfurization of model oil in an organic biphasic system catalysed by Fe3O4@SiO2–ionic liquid

The oxidation of DBT to sulfone catalyzed by Fe₃O₄/SiO₂/ionic liquid.

Simultaneous Enrichment of Polycyclic Aromatic Hydrocarbons and Cu(2+) in Water Using Tetraazacalix[2]arene[2]triazine as a Solid-Phase Extraction Selector

On the basis of the definite retention mechanism proven by the stationary phase for high-performance liquid chromatography, tetraazacalix[2]arene[2]triazine featuring multiple recognition sites was assessed as a solid-phase extraction (SPE) selector. The applicability of its silica support was used for the extraction of trace amounts of polycyclic aromatic hydrocarbons (PAHs) and Cu(2+) in aqueous samples, followed by high-performance liquid chromatography fluorometric and graphite furnace atomic absorption spectrometric determination. On the basis of the π-π interaction with PAHs and the chelating interaction with Cu(2+), the simultaneous extraction of PAHs and Cu(2+) and stepwise elution through tuning the eluent were successfully achieved, respectively. The SPE conditions affecting the extraction efficiency were optimized, including type and concentration of organic modifier, sample solution pH, flow rate, and volume. As a result of the special adsorption and desorption mechanism, high extraction efficiency was achieved with relative recoveries of 94.3-102.4% and relative standard deviations of less than 10.5%. The limits of detection were obtained with 0.4-3.1 ng L(-1) for PAHs and 15 ng L(-1) for Cu(2+), respectively. The method was applied to the analyses of PAHs and Cu(2+) in Xiliu Lake water samples collected in Zhengzhou, China.

Preparation of size-controlled magnetite nanoparticles with a graphene and polymeric ionic liquid coating for the quick, easy, cheap, effective, rugged and safe extraction of preservatives from vegetables

Size-controlled magnetite nanoparticles (Fe3O4) with 200-1000nm were synthesized by co-precipitation method. Then Fe3O4@SiO2@G@PIL was synthesized and used as modified QuEChERS adsorbent for the determination of preservatives in vegetables. The size of about 200nm of Fe3O4 in Fe3O4@SiO2@G@PIL was selected as optimum size to clean-up. It not only exerted the nanometer features of magnetic nanoparticles, but also displayed the large specific surface area of graphene (G) and the solvent effects of polymeric ionic liquids (PILs). Various experimental parameters have been investigated. Under the optimized conditions, a simple, rapid and effective method for the determination of 20 preservatives residues in vegetables was established by modified QuEChERS to gas chromatography/mass spectrometry (GC-MS) analysis. The good linearity with correlation coefficients (R(2)) of 0.9972-0.9999 was obtained over the range of 0.02-2.00mg/L for 20 preservatives. The detection limits of the proposed method for 20 preservatives ranged from 0.82 to 6.64μg/kg. The adsorbent was successfully applied for extraction and determination of preservatives in vegetable samples, which thus was time-saving with keeping good clean-up performance.

Magnetic solid phase extraction using ionic liquid-coated core-shell magnetic nanoparticles followed by high-performance liquid chromatography for determination of Rhodamine B in food samples

Three hydrophobic ionic liquids (ILs) (1-butyl-3-methylimidazole hexafluorophosphate ([BMIM]PF6), 1-hexyl-3-methyl-imidazole hexafluoro-phosphate ([HMIM]PF6), and 1-octyl-3-methylimidazole hexafluorophosphate ([OMIM]PF6)) were used to coat Fe3O4@SiO2 nanoparticles (NPs) with core-shell structures to prepare magnetic solid phase extraction (MSPE) agents (Fe3O4@SiO2@IL). A novel method of MSPE coupled with high-performance liquid chromatography for the separation/analysis of Rhodamine B was then established. The results showed that Rhodamine B was adsorbed rapidly on Fe3O4@SiO2@[OMIM]PF6 and was released using ethanol. Under optimal conditions, the pre-concentration factor for the proposed method was 25. The linear range, limit of detection (LOD), correlation coefficient (R), and relative standard deviation (RSD) were found to be 0.50-150.00 μgL(-1), 0.08 μgL(-1), 0.9999, and 0.51% (n=3, c=10.00 μgL(-1)), respectively. The Fe3O4@SiO2 NPs could be re-used up to 10 times. The method was successfully applied to the determination of Rhodamine B in food samples.

Modified surface-active ionic liquid-coated magnetic graphene oxide as a new magnetic solid phase extraction sorbent for preconcentration of trace nickel

General procedure for preconcentration/recovery of nickel ions using modified surface-active ionic liquid-coated magnetic graphene oxide nanocomposite.

New solid phase microextraction fiber based on an eggshell membrane coating for determination of polycyclic aromatic hydrocarbons

In this work, we introduced a novel soluble eggshell membrane protein (SEP) coating for the fabrication of a solid phase microextraction (SPME) fiber for the first time.

Magnetic solid-phase extraction based on modified ferum oxides for enrichment, preconcentration, and isolation of pesticides and selected pollutants

Recently, a simple, rapid, high-efficiency, selective, and sensitive method for isolation, preconcentration, and enrichment of analytes has been developed. This new method of sample handling is based on ferum oxides as magnetic nanoparticles (MNPs) and has been used for magnetic solid-phase extraction (MSPE) of various analytes from various matrices. This review focuses on the applications of modified ferum oxides, especially modified Fe3O4 MNPs, as MSPE adsorbent for pesticide isolation from various matrices. Further perspectives on MSPE based on modified Fe3O4 for inorganic metal ions, organic compounds, and biological species from water samples are also presented. Ferum(III) oxide MNPs (Fe2O3) are also highlighted.