Green and efficient magnetic micro-solid phase extraction utilizing tea waste impregnated with magnetic nanoparticles for the analysis of ibuprofen in water samples by using UV-vis spectrophotometry

A green method based on magnetic micro-solid phase extraction (MNP-TW-μ-SPE) of tea waste impregnated with magnetic nanoparticles (MNP-TW) was developed for the extraction of ibuprofen (IBP) in water samples prior to UV-Vis spectrophotometric analysis. Experimenting parameters that affect the extraction efficiency of IBP, such as pH of the sample solution, sorbent dosage, extraction time, ionic strength, volume of the sample, type of desorption solvent, desorption time, and desorption volume, were studied and optimized in detail. The characterization studies for the MNP-TW were carried out by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction spectrometry (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), Brunauer-Emmett-Teller (BET) analysis, a vibrating sample magnetometer (VSM), and thermogravimetric analysis (TGA). Under the optimum conditions, the linearity ranges from 30 to 700 μg L-1 for IBP, with determination coefficients (R2) of 0.9983. The limit of detection (LOD) and limit of quantification (LOQ) were 9.40 μg L-1 and 28.50 μg L-1, respectively. The method also demonstrated good precision in reproducibility (RSD ≤ 1.53%), repeatability (RSD ≤ 1.48%), and recovery (86-115%). This method represents the advantages of low solvent consumption, flexibility, and better sensitivity compared to other studies employing spectrophotometric analysis. The usage of tea waste in the extraction process presents many advantages, as it is biodegradable, versatile, and contributes to an intelligent and sustainable economic strategy projected toward a circular economy approach.

Preparation of COF-coated nickel foam adsorbents for dispersive solid-phase extraction of 16 polycyclic aromatic hydrocarbons from Chinese herbal medicines

Covalent organic framework coated nickel foam (NF@COF) was prepared as a sorbent for the dispersive solid phase extraction (DSPE) of polycyclic aromatic hydrocarbons (PAHs) from Chinese herbal medicines (CHMs) prior to their determination by gas chromatography-mass spectrometry (GC-MS). The structure and morphology of the as-synthesized NF@COF were characterized by different techniques. Various key parameters affecting the performance of the DSPE method, including the amount of sorbent, desorption solvent, desorption volume and time, extraction time, and sample volume, were investigated. Under the optimized conditions, NF@COF combined with GC-MS was successfully applied to the determination of 16 PAHs in CHMs. The method showed wide linearity (20-2000 ng mL-1), low limits of determination (0.3-2.7 ng mL-1), and high recoveries (78.0-124%). These results revealed that NF@COF has the potential for efficient extraction of PAHs from complex samples.

Preparation of a magnetic phosphazene-based hyper crosslinked polymer for the fast and efficient extraction of chlorophenols from water and peach juice

Two magnetic phosphazene-based hyper crosslinked polymers (M-HCP-OP-TMC and M-HCP-OP-TCL) were newly synthesized by the reaction of Friedel-Crafts acylation, and the M-HCP-OP-TMC showed an excellent extraction capability and rapid adsorption kinetics for chlorophenols as an adsorbent. Then, an efficient analytical method was built for the preconcentration and quantification of chlorophenols from water and peach juice samples by combining M-HCP-OP-TMC based magnetic solid-phase extraction (MSPE) with HPLC-UV detection. The linear response range for the chlorophenols by the method was 0.21-100.0 ng mL-1 for water sample, and 0.36-100.0 ng mL-1 for peach juice sample. The detection limits (S/N = 3) of the proposed method for the analytes were 0.07- 0.25 ng mL-1 and 0.12-0.45 ng mL-1 for water and peach juice samples, respectively. The method recoveries for the spiked samples were in the range of 93.1%-117.1%, and the relative standard deviations were less than 10%. The adsorption of the chlorophenols with the M-HCP-OP-TMC was mainly contributed by π-π stacking and hydrophobic interactions. The results indicate that the method was sensitive and accurate enough for the determination of the chlorophenols from real samples.

A magnetic solid phase extraction microfluidic chip coupled with gas chromatography-mass spectrometry for the determination of polycyclic aromatic hydrocarbons in aqueous samples

In this paper, we designed and manufactured a reliable magnetic solid phase extraction (MSPE) microfluidic chip for determination of polycyclic aromatic hydrocarbons (PAHs) in water combined with gas chromatography-mass spectrometry. Sample loading, washing and elution are implemented with microinjection pump and integrated on a single chip, which reduced manual operation. Magnets were used to fix octadecyl/phenyl bifunctional Fe3O4@SiO2 extractant to avoid the design of weir structure in extraction chamber. The whole microfluidic chip was simple and low cost. Based on the microfluidic chip extraction platform, the on-chip MSPE method for the determination of PAHs was optimized and established. The results showed that this method required only 2 mL of sample, 2 mg of extractant, and 50 μL of elution organic solvent for whole on-chip MSPE process, which was environmentally friendly and consistent with green chemistry. Method verification results were displayed which the linear range of five PAHs was between 1-100 ng/mL with good linearity (R2≥ 0.9985), and the detection limits (S/N = 3) were 0.08-0.26 ng/mL. The RSDs of intra-day precision (n=6) and inter-day precision (n=9) for PAHs were less than 6.1 % and 7.2 %, respectively. Enrichment factors were determined to be 31.3-37.7. The recoveries of river water, tap water, bottle water, waste water and urine at three spiked levels were in the range of 89.9% to 113.7% and the matrix effect values were between 83.8% to 109.6%. The extraction platform has the advantages of accurate analysis, simple design and cost-effective, which is conducive to the widespread use of microfluidic chips.

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.

Free Fatty Acid from Waste Palm Oil Functionalized Magnetic Nanoparticles Immobilized on Surface Graphene Oxide as a New Adsorbent for Simultaneously Detecting Hazardous Polycyclic Aromatic Hydrocarbons and Phthalate Esters in Food Extracts

A newly synthesized free fatty acids from waste palm oil functionalized magnetic nanoparticles immobilized on the surface of graphene oxide (FFA@MNP-GO) was successfully synthesized and characterized in this research. The combinations of long alkyl chain of free fatty acid with graphene oxide that consists of large delocalized 77-electron systems and abundant of hydrophilic groups with hydroxyl, epoxide and carboxylic groups offer the determination of simultaneous wide range of polarities of organic pollutants in real matrices through hydrogen bonding, hydrophobic and 77-77 interactions. The fabricated adsorbent was successfully applied as a magnetic solid phase extraction (MSPE) adsorbent for the simultaneous separation of selected phthalate esters (PAEs) and polycyclic aromatic hydrocarbons (PAHs) in apple and cabbage extracts prior to their high performance liquid chromatography with diode-array detector (HPLC-DAD) determination. Factors affecting the extraction efficiency such as amount of adsorbent, desorption solvent, volume of desorption solvent, extraction time, desorption time, pH and sample volume were investigated and optimized. The results revealed that under optimal conditions, the detection limit of selected PAEs and PAHs were in the range of 0.56-0.97 ng mL^-1 and 0.02-0.93 ng mL^-1, respectively. The spiked recoveries of real apple and cabbage extracts for PAEs and PAHs were in the range of 81.5-117.6% with good relative standard deviation (RSD) (n = 5) less than 10% and 86.7-118.2% with acceptable RSDs (n = 5) ranging from 1.5 to 11.0%, respectively. This study reported for the first time the use of MSPE procedure for simultaneous determination of chosen PAHs and PAEs in real samples including apple and cabbage extracts by using new adsorbent, FFA@MNP-GO.

Analyzing the surface of functional nanomaterials-how to quantify the total and derivatizable number of functional groups and ligands

Functional nanomaterials (NM) of different size, shape, chemical composition, and surface chemistry are of increasing relevance for many key technologies of the twenty-first century. This includes polymer and silica or silica-coated nanoparticles (NP) with covalently bound surface groups, semiconductor quantum dots (QD), metal and metal oxide NP, and lanthanide-based NP with coordinatively or electrostatically bound ligands, as well as surface-coated nanostructures like micellar encapsulated NP. The surface chemistry can significantly affect the physicochemical properties of NM, their charge, their processability and performance, as well as their impact on human health and the environment. Thus, analytical methods for the characterization of NM surface chemistry regarding chemical identification, quantification, and accessibility of functional groups (FG) and surface ligands bearing such FG are of increasing importance for quality control of NM synthesis up to nanosafety. Here, we provide an overview of analytical methods for FG analysis and quantification with special emphasis on bioanalytically relevant FG broadly utilized for the covalent attachment of biomolecules like proteins, peptides, and oligonucleotides and address method- and material-related challenges and limitations. Analytical techniques reviewed include electrochemical titration methods, optical assays, nuclear magnetic resonance and vibrational spectroscopy, as well as X-ray based and thermal analysis methods, covering the last 5-10 years. Criteria for method classification and evaluation include the need for a signal-generating label, provision of either the total or derivatizable number of FG, need for expensive instrumentation, and suitability for process and production control during NM synthesis and functionalization.

Development of a syringe membrane-based microextraction method based on metal-organic framework mixed-matrix membranes for preconcentration/extraction of polycyclic aromatic hydrocarbons in tea infusion

Inevitably, the residues of polycyclic aromatic hydrocarbons (PAHs) in tea leaves will be transferred to hot tea infusion, constituting a certain drinking risk; consequently, it is imperative to develop rapid, sensitive, and robust approaches for their trace-level detection. Herein, we developed a syringe membrane-based microextraction (SMME) method for preconcentration/extraction of PAHs in tea infusions. This method utilized metal-organic framework-mixed matrix membranes (MOF-MMMs) as adsorbents, which anchored the nanoparticles of MOFs onto the surface of PVDF membrane. The UiO-66 (Zr)-based MMM possessed high Brunauer-Emmett-Teller (BET) surface area (320.5 m² g^-1) and pore volume (0.18 cm³ g^-1), thus enhancing extraction/adsorption efficiency. Under optimized conditions, the limits of detection for PAHs reached as low as 0.02-0.08 μg L^-1 with extraction recoveries of 85.5-102.1%, and the inter-day and intra-day precision was lower than 8.4% in tea infusions. Consequently, the SMME/HPLC-DAD method shows a great potential in conventional monitoring of PAHs in tea samples.

Magnetic solid phase extraction of heterocyclic aromatic hydrocarbons from environmental water samples with multiwalled carbon nanotube modified magnetic polyamido-amine dendrimers prior to gas chromatography-triple quadrupole mass spectrometer

Present study described a sensitive and efficient method for determination of heterocyclic aromatic hydrocarbons using multiwalled carbon nanotubes modified magnetic polyamido-amine dendrimers (MNPs@PAMAM-Gn@MWCNTs) as adsorbent for magnetic solid-phase extraction (MSPE) coupled with gas chromatography-triple quadrupole mass spectrometer (GC-MS/MS). Some pivotal parameters including PAMAM generation, adsorbent dosage, adsorption time, elution time and volume, pH and humic acid concentration were investigated to achieve the best adsorption efficiencies. Under the optimal conditions, 7-methylquinoline, dibenzothiophene and carbazole had good linearity in the concentration range of 0.005-20 μg L ^- 1, 9-methylcarbazole, 4-methyldibenzothiophene and 4,6-dimethyl dibenzothiophene had good linearity in the concentration range of 0.001-20 μg L ^- 1. All the correlation coefficients were higher than 0.996. The detection limits of the targets were in the range of 2.2 × 10^-4-1.8 × 10^-3 μg L ^- 1 with precisions less than 8.28% (n = 6). The enrichment factors were in the range of 141-147. The spiked recoveries were in the range of 87.0%-115.1% (n = 3). These results indicated that the method could be a reliable alternative tool for monitoring trace heterocyclic aromatic hydrocarbons in environmental water samples.

Solid-phase extraction using chloropropyl functionalized sol-gel hybrid sorbent for simultaneous determination of organophosphorus pesticides in selected fruit samples

A new sol-gel hybrid methyltrimethoxysilane-chloropropyltriethoxysilane was prepared as sorbent for solid-phase extraction. The extraction efficiency of the prepared sol-gel hybrid methyltrimethoxysilane-chloropropyltriethoxysilane was assessed by using three selected organophosphorus pesticides, namely, chlorpyrifos, profenofos, and malathion. Gas chromatography-mass spectrometry was used for detection of organophosphorus pesticides. Several vital parameters were optimized to identify the best extraction conditions. Under the optimum extraction conditions, solid-phase extraction-methyltrimethoxysilane-chloropropyltriethoxysilane method showed good linearity range (0.05-1 μg/mL) with coefficient of determination more than 0.995. The limits of detection obtained were in the range of 0.01-0.07 μg/mL and limits of quantification ranging from 0.03 to 0.21 μg/mL. The limits of detection obtained for the developed method were 2.3-6.5× lower than the limits of detection of commercial octadecyl silica sorbent. Real samples analysis was carried out by applying the developed method on red apple and purple grape samples. The developed method exhibited good recoveries (88.33-120.7%) with low relative standard deviations ranging from 1.6 to 3.3% compared to commercial octadecyl silica sorbent, which showed acceptable recoveries (70.3-100.2%) and relative standard deviations (6.3-8.8%). The solid-phase extraction-methyltrimethoxysilane-chloropropyltriethoxysilane method is presented as an alternative extraction method for determination of organophosphorus pesticides.

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.

A study on the removal of propyl, butyl, and benzyl parabens via newly synthesised ionic liquid loaded magnetically confined polymeric mesoporous adsorbent

This study investigated the effectiveness of ionic liquids (ILs) loaded onto the surface of a polymeric adsorbent (βCD-TDI) grafted with modified magnetic nanoparticles (MNPs) via an analysis of water treatment, which resulted in high removal of selected endocrine-disrupting chemicals (parabens). The syntheses of MNPs, MNP-βCD-TDI, and IL-MNP-βCD-TDI were characterised and compared using Fourier transform infrared (FT-IR) spectroscopy, carbon-hydrogen-nitrogen (CHN) analysis, vibrating sample magnetometry (VSM), scanning electron microscopy (SEM), transmission electron microscopy (TEM), the Brunauer-Emmett-Teller (BET) method, thermogravimetric analysis (TGA), and X-ray diffraction (XRD). The results of SEM and TEM indicated that the pore size distribution exhibited mesoporous characteristics with a small surface area (BET analysis: 42.95 m2 g-1). Furthermore, a preliminary sorption experiment demonstrated the ability of IL-MNP-βCD-TDI to enhance not only the sorption capacity, but also the removal of propyl paraben (PP), butyl paraben (BP), and benzyl paraben (ArP). The adsorption process appeared to be pH-dependent, and hence the optimum pH of 6 was selected for a subsequent batch adsorption study of all the studied parabens with an equilibrium time of 80 min. Next, in an attempt to investigate the interactions that occur between the adsorbent and the adsorbates, adsorption kinetics and isotherm studies were performed. All the studied parabens were found to best fit pseudo-second-order kinetics and the Freundlich isotherm with R 2 > 0.98 at room temperature (298 K). The interaction of the host-guest inclusion complex and the π-π interaction between βCD and a selected paraben compound (ArP) were identified by performing 1H nuclear magnetic resonance (NMR), together with ultraviolet-visible (UV-vis) spectroscopic analysis. Finally, the adsorption efficiency of the developed material was practically tested on tap water, drain water, and industrial wastewater, which revealed a significant removal of parabens of up to 60-90% in comparison with a prior analysis.

Synthesis of piperazine functionalized magnetic sporopollenin: a new organic-inorganic hybrid material for the removal of lead(II) and arsenic(III) from aqueous solution

The present work describes the successful functionalization/magnetization of bio-polymeric spores of Lycopodium clavatum (sporopollenin) with 1-(2-hydroxyethyl) piperazine. Analytical techniques, i.e., Fourier transform infrared (FT-IR), field emission scanning electron microscope (FESEM), energy-dispersive X-ray spectroscopy (EDS), and vibrating sample magnetometer (VSM), were used to confirm the formation of 1-(2-hydroxyethyl) piperazine-functionalized magnetic sporopollenin (MNPs-Sp-HEP). The proposed adsorbent (MNPs-Sp-HEP) was used for the removal of noxious Pb(II) and As(III) metal ions from aqueous media through a batch-wise method. Different experimental parameters were optimized for the effective removal of selected noxious metal ions. Maximum adsorption capacity (q _m ) 13.36 and 69.85 mg g^-1 for Pb(II) and As(III), respectively, were obtained. Thermodynamic parameters such as free energy (ΔG°), entropy (ΔS°), and enthalpy (ΔH°) were also studied from the adsorption results and were used to elaborate the mechanism of their confiscation. The obtained results indicated that newly adsorbent can be successfully applied for the decontamination of noxious Pb(II) and As(III) from the aqueous environment.

An ionic liquid loaded magnetically confined polymeric mesoporous adsorbent for extraction of parabens from environmental and cosmetic samples

Schematic illustration of MSPE procedure for paraben analysis using a new ionic liquid loaded magnetically confined polymeric mesoporous material.

Superhydrophobic magnetic nanoparticle-free fatty acid regenerated from waste cooking oil for the enrichment of carcinogenic polycyclic aromatic hydrocarbons in sewage sludges and landfill leachates

In this study, Fe₃O₄ nanoparticles grafted with superhydrophobic free fatty acids from waste cooking oil (FFA@MNP) were successfully fabricated as an adsorbent for the magnetic solid phase extraction (MSPE) technique.