Polyaniline-dicationic ionic liquid coated with magnetic nanoparticles composite for magnetic solid phase extraction of polycyclic aromatic hydrocarbons in environmental samples

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.

Efficient extraction performance and mechanisms of Cd2+ and Pb2+ in water by novel dicationic ionic liquids

Ten novel hydrophobic dicationic ionic liquids (DILs) were synthesized and applied for the extraction of heavy metals in aqueous solutions. Their physicochemical properties were measured at ambient temperature, and the leaching behaviors of the as-prepared DILs in water were assessed by TOC analysis. Metal extraction experiments were carried out to evaluate the extraction performances of the DILs. It was found that the extraction rates of up to 0.45 and 0.53 mg·(g·min)-1 were achieved with 100 mg DILs for 5 mL of 5 mg/L Cd2+ and Pb2+ solutions. Besides, the extraction efficiencies of Cd2+ and Pb2+ were respectively up to 95.48% and 98.46%, when the volumes of the simulated wastewater were expanded by a factor of 20 at a constant extraction phase ratio (1000 mg DILs for 50 mL of 5 mg/L Cd2+ or Pb2+ solutions). The reusability of the novel DILs was successfully proved by the back-extraction experiments with 0.5 M HNO3. Finally, taking Cd2+ extraction as an example, the extraction mechanism based on FTIR analysis and quantum chemical calculations showed that both S and O atoms in the anions of DILs had physical and quasi-chemical interactions with Cd2+, which were stronger than the electrostatic attraction.

Ultrasound-assisted adsorption approach for desulfurization of n-heptane using nitrogen-doped magnetic carbon dot nanocomposite

Desulfurization is an important process that not only affects the quality and performances of fuels but also is of great importance from environmental aspects. In this research, nitrogen-doped magnetic carbon dots nanocomposite was synthesized and characterized, and it's potential in adsorptive removal of thiophenes (i.e., thiophene, benzothiophene, and dibenzothiophene) from n-heptane (i.e., as model fuel) was investigated. After optimization of adsorption process, the removal efficiency was obtained above 95% for all of studied thiophenes. Besides that, it was concluded that using ultrasound during the adsorption process could enhance the maximum adsorption capacity. Langmuir model was able to appropriately describe the adsorption isotherm data, where the maximum equilibrium adsorption capacities for thiophene, benzothiophene and dibenzothiophene were obtained as 90.22, 96.51 and 100.38 mgg-1, respectively. The analysis of kinetic data also revealed that all thiophenes were being adsorbed following Pseudo-second-order model. To regenerate the adsorbent, the desorption process was also investigated using different solvents under different conditions, methanol was found as effective solvent for regeneration. The proposed adsorbent was used successfully for the removal of pollutants in a gasoline sample.

Facile fabrication of naphthalene-functionalized magnetic nanoparticles for efficient extraction of polycyclic aromatic hydrocarbons from environmental water and fish samples

In this study, naphthalene-modified magnetic nanoparticles (Fe3O4@Nap) were simply prepared based on specific chelation interaction between phosphate groups and metal ions on Fe3O4 surface. The resultant Fe3O4@Nap were characterized by FTIR, BET, SEM, TEM, NAM, TGA, and VSM techniques. With Fe3O4@Nap as adsorbent, the polycyclic aromatic hydrocarbons (PAHs) were efficiently extracted by magnetic solid-phase extraction (MSPE) from environmental water and fish samples through the π-π interaction between modified naphthalene groups and PAHs, followed by their determination by GC-MS/MS. The key parameters influencing the extraction efficiency were investigated. Under the optimized conditions, the Fe3O4@Nap-based MSPE/GC-MS/MS method proposed in this paper was evaluated and applied for analyzing PAHs in environmental water and fish samples. And the proposed MSPE/GC-MS/MS method exhibited good linearities for water samples (in the range of 0.1-10 ng/mL, R2 >0.9945) and for fish samples (in the range of 1-100 ng/g, R2 > 0.9905). The limits of detection (LODs) for water and fish samples were 0.004-0.031 ng/mL and 0.07-0.28 ng/g, respectively. Additionally, this method exhibited desirable accuracy and precision. The PAH recovery values from water and fish samples ranged from 81.5% to 109.6% with inter- and intra-day relative standard deviations (RSDs) of less than 12.8%. The MSPE/GC-MS/MS method was successfully applied to the analysis of real environmental water and fish samples. Overall, the newly synthesized Fe3O4@Nap exhibited high sensitivity, specificity, reusability, repeatability, and it could efficiently extract PAHs from environmental water and fish samples by MSPE.

Rapid and Sensitive Detection of Polycyclic Aromatic Hydrocarbons in Tea Leaves Using Magnetic Approach

A rapid and efficient method using an alkyl-functionalized magnetic nanoparticles-based extraction technique combined with Ultra-High Performance Liquid Chromatography was developed for the detection of trace amounts of polycyclic aromatic hydrocarbons in tea leaves. As a popular coating for chromatographic column packing materials, C₁₈-alkyl has been demonstrated to be effective in separating polycyclic aromatic hydrocarbons. Additionally, the magnetism of the nanomaterials accelerates the extraction process while their high surface ratio enables desirable dispersity in the sample matrix. Meanwhile, the adsorbents can be washed and reused 30 times without compromising recovery, which greatly reduces the budget. The effects of various parameters were investigated and optimized, and the recoveries for five analytes were in the range of 84.8-105.4%. The RSD of intra-day and inter-day were below 11.9% and 6.8%, respectively. The limits of detection and limits of quantification ranged from 1.69-9.97 ng g^-1 and 5.12-30.21 ng g^-1, indicating satisfactory sensitivity. Thus, the proposed methodology is rapid, highly efficient, and economical, and it expands the application of magnetic cleanup approaches in complex food matrices.

Investigating analyte breakthrough under non-linear isotherm conditions during solid phase extraction facilitated by non-targeted analysis with comprehensive two-dimensional gas chromatography time-of-flight mass spectrometry

Solid phase extraction (SPE) sample preparation for the analysis of complex organic mixtures is often applied assuming all analytes of interest will preconcentrate on the stationary phase. This assumption ignores the reality that extraction is a dynamic interactive process and a diverse range of affinities for the stationary phase will result in equally diverse breakthrough volumes due to competitive sorption processes. To study this dynamic interactive process, and further to take advantage of it, we extracted a JP-8 jet fuel spiked with 40 ppm of a polar compound mix with silica and alumina SPE cartridges and analyzed sequential extracted fractions of the fuel to both assess the shifting chemical landscape present in the extraction and the impact of both SPE stationary phases on this process. Tile-based 1v1 comparative analysis (a recently reported extension of tile-based Fisher ratio analysis) was used to discover the (polar) compounds whose concentrations change between extracted fractions, discovering 21 compounds extracted with silica and 27 compounds extracted with alumina with at least a 2-fold change in concentration from the neat sample relative to the first 1 mL pass fraction sample. These compounds were quantified in each fraction to construct concentration ratio profiles, defined as the concentration ratio for a given SPE fraction per analyte compound relative to the analyte concentration in the neat fuel, for which the extraction behavior for each analyte could be assessed. These analyte compounds were found to breakthrough at different rates, with some analytes remaining on the column indefinitely (until extracted with a subsequent polar solvent) and other analytes eluting before the extraction is complete. Furthermore, in a comparison of the effect of selected stationary phase, alumina was found to retain oxygen-containing phenolic compounds to a greater extent than silica. Principal component analysis (PCA) was used to analyze the concentration ratio profiles of the various trace analytes in the JP8 fuel (phenols, indoles, etc.) in the context of their stationary phase affinity (silica or alumina) and competitive sorption behavior.

Poly-(MMA-IL) filter paper: A new class of paper-based analytical device for thin-film microextraction of multi-class antibiotics in environmental water samples using LC-MS/MS analysis

A paper-based polymeric ionic liquid (p-Poly-(MMA-IL)) was successfully developed by grafting the polymeric ionic liquid on the surface of commercial filter paper (FP) by using the dipping method, presenting a new cost-effective film. The newly developed p-Poly-(MMA-IL) FP was then applied as a paper-based thin-film microextraction (p-TFME) analytical device to extract 14 compounds as representative of five groups of antibiotic drugs, which were sulfonamides, tetracyclines, fluoroquinolones, penicillin and macrolides in environmental water samples. Besides, p-Poly-(MMA-IL) FP, p-Poly-(MMA) FP, and unmodified filter paper were successfully characterised by FTIR, NMR, FESEM, TGA, and XRD techniques. They underwent significant parameters optimisation, which affected the extraction efficiency. Under optimal conditions, the proposed (p-Poly-(MMA-IL) FP-TFME) device method was evaluated and applied to analyse multi-class antibiotic drugs in environmental water samples by using a liquid chromatography-mass spectrometry (LC-MS). The validation method showed that a good linearity (0.1 μg L^-1 - 500 μg L^-1) was noted (R² > 0.993, n = 3). Detection and quantification limits were within 0.05 μg L^-1 - 4.52 μg L^-1 and 0.15 μg L^-1 - 13.6 μg L^-1, respectively. The relative standard deviation (RSD) values ranged at 1.4%-12.2% (intra-day, n = 15) and 4.4%-11.0% (inter-day, n = 10). The extraction recoveries of environmental water samples ranged from 79.1% to 126.8%, with an RSD of less than 15.4% (n = 3). The newly developed paper-based polymeric ionic liquid (p-Poly-(MMA-IL) FP) for analysis of multi-class antibiotic drugs under the p-TFME analytical device procedure was successfully achieved with limited sample volume and organic solvent, fast extraction, and feasible in daily analysis. The detection concentration and relative RSD of multi-class antibiotics determined in various environmental water samples by the proposed method (n = 5) were within 0.44 μg L^-1 - 54.41 μg L^-1 and 0.69%-15.56%, respectively. These results signified the potential of the p-Poly-(MMA-IL) FP-TFME device as an efficient, sensitive and environmentally friendly approach for analysing antibiotics.

Polyaniline and Polyaniline-Based Materials as Sorbents in Solid-Phase Extraction Techniques

Polyaniline (PANI) is one of the best known and widely studied conducting polymers with multiple applications and unique physicochemical properties. Due to its porous structure and relatively high surface area as well as the affinity toward many analytes related to the ability to establish different types of interactions, PANI has a great potential as a sorbent in sample pretreatment before instrumental analyses. This study provides an overview of the applications of polyaniline and polyaniline composites as sorbents in sample preparation techniques based on solid-phase extraction, including conventional solid-phase extraction (SPE) and its modifications, solid-phase microextraction (SPME), dispersive solid-phase extraction (dSPE), magnetic solid-phase extraction (MSPE) and stir-bar sorptive extraction (SBSE). The utility of PANI-based sorbents in chromatography was also summarized. It has been shown that polyaniline is willingly combined with other components and PANI-based materials may be formed in a variety of shapes. Polyaniline alone and PANI-based composites were successfully applied for sample preparation before determination of various analytes, both metal ions and organic compounds, in different matrices such as environmental samples, food, human plasma, urine, and blood.

Ionic Liquid-Based Polymer Nanocomposites for Sensors, Energy, Biomedicine, and Environmental Applications: Roadmap to the Future

Current interest toward ionic liquids (ILs) stems from some of their novel characteristics, like low vapor pressure, thermal stability, and nonflammability, integrated through high ionic conductivity and broad range of electrochemical strength. Nowadays, ionic liquids represent a new category of chemical-based compounds for developing superior and multifunctional substances with potential in several fields. ILs can be used in solvents such as salt electrolyte and additional materials. By adding functional physiochemical characteristics, a variety of IL-based electrolytes can also be used for energy storage purposes. It is hoped that the present review will supply guidance for future research focused on IL-based polymer nanocomposites electrolytes for sensors, high performance, biomedicine, and environmental applications. Additionally, a comprehensive overview about the polymer-based composites' ILs components, including a classification of the types of polymer matrix available is provided in this review. More focus is placed upon ILs-based polymeric nanocomposites used in multiple applications such as electrochemical biosensors, energy-related materials, biomedicine, actuators, environmental, and the aviation and aerospace industries. At last, existing challenges and prospects in this field are discussed and concluding remarks are provided.

Separation and Enrichment of Selected Polar and Non-Polar Organic Micro-Pollutants—The Dual Nature of Quaternary Ammonium Ionic Liquid

In this study, the dual nature of quaternary ammonium ionic liquid–didecyldimethylammonium perchlorate, [DDA][ClO4], was evaluated. A novel and sensitive in situ ionic liquid dispersive liquid–liquid microextraction method (in situ IL-DLLME) combined with magnetic retrieval (MR) was applied to enrich and separate selected organic micro-pollutants, both polar and non-polar. The magnetic support relied on using unmodified magnetic nanoparticles (MNPs) prepared by the co-precipitation of Fe2+/Fe3+ (Fe3O4). The separation technique was on-lined with high-performance liquid chromatography (HPLC–DAD) verified by inverse gas chromatography. An anion exchanger, NaClO4, was added to form an in situ hydrophobic IL. The fine droplets of [DDA][ClO4], molded in aqueous samples, functioned as an extractant for isolating the studied compounds. Then the carrier MNPs were added to separate the IL from the water matrix. The supernatant-free sample was desorbed in acetonitrile (MeCN) and injected into the HPLC system. The applicability of [DDA][ClO4] as an extraction solvent in the MR in situ IL-DLLME method was checked by the selectivity parameters (Sij∞) at infinite dilution. The detection limit (LOD) ranged from 0.011 to 0.079 µg L−1 for PAHs and from 0.012 to 0.020 µg L−1 for benzophenones. The method showed good linearity with correlation coefficients (r2) ranging from 0.9995 to 0.9999.

Exploring a novel silicone surfactant-based deep eutectic solvent functionalized magnetic iron particles for the extraction of organophosphorus pesticides in vegetable samples

The current study discussed the use of silicone surfactant-based deep eutectic solvent as a surface modifier for magnetic iron particles (Fe₃O₄) to produce a novel adsorbent and its application for the extraction of organophosphorus pesticides (OPPs) in vegetable samples. A deep eutectic solvent (DES) was prepared using low toxic and inexpensive substances such as silicone surfactant (SS) and dodecanoic acid (DoAc). This new eco-friendly SS:DoAc based DES was explored as a substitution to traditional organic reagents for surface modification of Fe₃O₄ to increase the adsorption capacity and to reduce the matrix interferences, hazardous waste generation and environmental pollution. The newly synthesized SS:DoAc@Fe₃O₄ adsorbent was successfully characterized and applied in magnetic solid phase extraction (MSPE). Under optimized conditions, the proposed approach exhibited excellent linearity ranging from 0.1 to 200 µg/kg (R² ≥ 0.9970), low detection limit (0.03-0.1 µg/kg) and acceptable relative recovery (80-119 %) for the studied OPPs.

Integrated ultrasound-assisted magnetic solid-phase extraction for efficient determination and pre-concentration of polycyclic aromatic hydrocarbons from high-consumption soft drinks and non-alcoholic beers in Iran

In the present research, an ultrasound-assisted magnetic solid-phase extraction coupled with a gas chromatography-mass spectrometry hybrid system was developed for extraction/determination of trace amounts of polycyclic aromatic hydrocarbons in high-consumption soft drinks and non-alcoholic beers in Iran using magnetite graphene oxide adsorbent. The magnetite graphene oxide was characterized by scanning electron microscope, transmission electron microscopy, Fourier-transform infrared spectroscopy, X-ray diffraction, and vibrating-sample magnetometer techniques. The highest extraction recovery (73.05 to 95.56%) and enrichment factor (90.65 to 106.38) were obtained at adsorbent mass: 10 mg, adsorption time: 30 min, salt addition: sodium chloride 10% w/v, desorption time: 20 min, eluent type: hexane: acetone (1:1, v/v), and desorption solvent volumes: 200 μL. Under optimum conditions, the linearity range for polycyclic aromatic hydrocarbons determination was 0.2-200 ng mL^-1  with coefficient of determination> 0.993, limit of detection = 0.09-0.21 ng mL^-1 , limit of quantitation = 0.3-0.7 ng mL^-1 , and relative standard deviation < 8.1%, respectively. Relative recoveries in spiked real samples ranged from 94.67 to 109.45 % with standard deviation < 6.05%. The proposed method is effective, sensitive, reusable and it is promising for the analysis of polycyclic aromatic hydrocarbons residues in environmental samples. This article is protected by copyright. All rights reserved.

Nanomaterials with Excellent Adsorption Characteristics for Sample Pretreatment: A Review

Sample pretreatment in analytical chemistry is critical, and the selection of materials for sample pretreatment is a key factor for high enrichment ability, good practicality, and satisfactory recoveries. In this review, the recent progress of the sample pretreatment methods based on various nanomaterials (i.e., carbon nanomaterials, porous nanomaterials, and magnetic nanomaterials) with excellent adsorption efficiency, selectivity, and reproducibility, as well as their applications, are presented. Due to the unique nanoscale physical–chemical properties, magnetic nanomaterials have been used for the extraction of target analytes by easy-to-handle magnetic separation under a magnetic field, which can avoid cumbersome centrifugation and filtration steps. This review also highlights the preparation process and reaction mechanism of nanomaterials used in the sample pretreatment methods, which have been applied for the extraction organophosphorus pesticides, fluoroquinolone antibiotics, phenoxy carboxylic acids, tetracycline antibiotics, hazardous metal ions, and rosmarinic acid. In addition, the remaining challenges and future directions for nanomaterials used as sorbents in the sample pretreatment are discussed.

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.

Chitosan and dicationic ionic liquid intercalated clay-coated solid-phase microextraction fiber for determination of sixteen polycyclic aromatic hydrocarbons in coffee and tea samples

In the present study, solid-phase microextraction (SPME) fiber was prepared by coating clay (MMT)-chitosan (CH) and dicationic ionic liquid (DIL) onto the stainless-steel wire step by step. The characterization of fibers was performed by Fourier transform infrared spectroscopy, thermal analysis, x-ray diffraction analysis, and scanning electron microscopy. The prepared fibers were evaluated for separation and determination of 16 polycyclic aromatic hydrocarbons (PAHs) in coffee and tea samples in headspace- and direct immersion-SPME by coupling with gas chromatography/mass spectrometry. The analytical performance of MMT/CH/DIL fibers was carried out for the extraction of PAHs and compared with the performance of carboxen/polydimethylsiloxane (CAR/PDMS) and divinylbenzene/CAR/PDMS (DVB/CAR/PDMS) fibers under optimized conditions. The wider linear ranges between 0.001 and 25 μg L^-1 with a coefficient of determination above 0.9962, low limits of detection between 0.0001 and 0.05 μg L^-1 and good intra-day repeatability from 2.45 to 6.48 % and fiber-to-fiber reproducibility from 3.19 % to 8.82 % were obtained for all PAHs in both methods with MMT/CH/octyl (O)-DIL fiber. The extraction recoveries of coffee and tea samples ranged from 87.5 to 112 % using the MMT/CH/O-DIL fiber in both SPME methods.

Utilization of montmorillonite nanocomposite incorporated with natural biopolymers and benzyl functionalized dicationic imidazolium based ionic liquid coated fiber for solid-phase microextraction of organochlorine pesticides prior to GC/MS and GC/ECD

A novel montmorillonite clay (MMT) bionanocomposite modified with chitosan (CH), carboxymethyl cellulose (CMC), and benzylimidazolium based dicationic ionic liquid with tetraethylene glycol linker (DIL) was fabricated on stainless steel wire by in situ process. The MMT-CH-CMC-DIL coated solid-phase microextraction (SPME) fiber was examined for the determination of organochlorine pesticides (OCPs) in real samples by HS-SPME-GC method using mass spectrometry (MS) and electron capture detector (ECD). Under optimized conditions, the proposed method exhibited low limits of detection (0.5 ng L^-1 with MS and 0.1 ng L^-1 with ECD detection), good linearities (R² = 0.9972-0.9993 with MS and 0.9987-0.9998 with ECD detection), favorable single-fiber repeatability, and fiber-to-fiber reproducibility (less than 8.2% and 9.9% for both types of detection) and high reusability around 125 cycles. Recovery studies were carried out for OCPs in tap water, green tea, and milk samples to verify the applicability of the developed SPME-GC method.

Trace-level monitoring of anti-cancer drug residues in wastewater and biological samples by thin-film solid-phase micro-extraction using electrospun polyfam/Co-MOF-74 composite nanofibers prior to liquid chromatography analysis

Sample preparation methods with high accuracy and matrix resistance will benefit the quick analysis of desired analytes in an intricate matrix, such as the monitoring of drug samples in biofluids. Herein, an electrospun composite, consisting of polyfam and a Co-metal organic framework- 74, was developed as a novel sorbent for the high-throughput solid-phase micro-extraction of certain anti-cancer drugs (sorafenib, dasatinib, and erlotinib hydrochloride) from wastewater and biological samples before high-performance liquid chromatography- ultraviolet analysis (HPLC-UV). The synthesis of the resulting composite nanofibers was confirmed using the techniques of Fourier transform-infrared spectroscopy, field emission scanning electron microscopy (FESEM), energy-dispersive X-ray spectroscopy (EDX), and powder X-ray diffraction (XRD). FESEM images illustrated irregular and bead-free nanofibers with a diameter range of 126.9-269.6 nm. Thanks to the incorporation of Co-MOF-74 into the polyfam network, the electrospun nanofibers displayed a large surface area, high porosity, and significant extraction efficiency toward target analytes. Under optimal experimental conditions, the linearity was achieved in the range of 0.1-1500.0 µg L^-1 for sorafenib and 0.5-1500.0 µg L^-1 for dasatinib and erlotinib hydrochloride, with a coefficient of determination of ≥0.9996. The detection limits (LODs) were calculated within the range of 0.03-0.20 µg L^-1. The relative standard deviation values (RSDs %) were in the range of 3.1%-8.6% (intra-day, n = 6) and 7.0%-10.3% (inter-day, n=3) in the span of three days. Ultimately, the application of the developed method was appraised for the quantification of trace amounts of the intended analytes in various spiked samples.

Application of curcumin as a green and new sorbent in deep eutectic solvent-based dispersive micro-solid phase extraction of several polycyclic aromatic hydrocarbons from honey samples prior to gas chromatography-mass spectrometry determination

A green, simple, and efficient dispersive micro-solid phase extraction method was developed for the extraction of polycyclic aromatic hydrocarbons from honey samples. In this method, for the first time, curcumin was used as an efficient and green sorbent to extract the analytes from the sample. After that the adsorbed analytes were eluted using a deep eutectic solvent prepared by mixing tetrabutylammonium chloride: ethylene glycol and analyzed by gas chromatography-mass spectrometry. Important experimental factors affecting adsorption and desorption steps of the method were optimized and under optimal experimental conditions, low limits of detection (0.14-0.37 ng/g) and quantification (0.49-1.3 ng/g), wide linear range (1.3-500 ng/g) with a coefficient of determination ≥0.994 were obtained. Relative standard deviation values for intra- and interday precisions were ≤7.5% for all of the analytes at a concentration of 2 ng/g for each analyte (n = 6). Extraction recovery of the method was in the range of 72-81%. Finally, 20 honey samples were analyzed and the analytes were successfully detected. The method is environment friendly because of the use of curcumin as a sorbent. Also, biodegradability of the used deep eutectic solvent components is another advantage of the method.

1-Octyl-3-methylimidazolium hexafluorophosphate-functionalised magnetic poly β-cyclodextrin for magnetic solid-phase extraction ofpyrethroids from tea infusions

In this study, a novel sorbent, 1-octyl-3-methylimidazolium hexafluorophosphate functionalised magnetic poly β-cyclodextrin, was successfully synthesised and applied to magnetic solid-phase extraction for the determination of pyrethroids in tea infusions. The sorbent was characterised by transmission electron microscopy, energy-dispersive spectroscopy, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, vibrating sample magnetometer and Brunauer-Emmett-Teller measurement. All factors affecting extraction efficiency, such as sorbent amount, extraction time, ionic strength and desorption conditions, were optimised individually. Under the chosen conditions, wide linearity (2.5-500 μg L^-1) with determination coefficients ranging from 0.9995 to 0.9999, low limits of detection of 0.32-0.54 μg L^-1 and good precision (intra-day: 2.6-7.0%; inter-day: 3.5-7.6%) were achieved for four pyrethroids in tea infusions. The relative recoveries of target analytes in real tea infusion samples were from 70% to 101% with relative standard deviations lower than 9.1%. We conclude that the proposed method is promising in the detection of pyrethroids in tea infusions.

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.

Rethinking the Applications of Ionic Liquids and Deep Eutectic Solvents in Innovative Nano-Sorbents

With the development of green chemistry and nano materials, new alternatives to traditional volatile solvents are one of many important hotspots in the field of nano materials. Ionic liquids (ILs) and deep eutectic solvents (DESs) as excellent alternative solvents are being applied in the innovation of nano-sorbents, including nanoparticles, nanogels, and nanofluid. ILs and DESs are often used as carriers/modifiers/dispersers of nano-sorbents to enhance the adsorption capacity and selectivity in the extraction procedure. Various extraction technologies, such as solid-phase extraction, solid-phase microextraction, micro-solid phase extraction, hollow fiber liquid phase microextraction, and magnetic solid-phase extraction, have also been promoted by them to achieve rapid development. This paper focused on the latest development of nano-sorbents based on ILs and DESs. The problems and bottlenecks encountered were analyzed in order to provide meaningful and valuable references for the related research and thus promote further development and application of alternative solvents-assisted nano-sorbents.

Ambient Levels, Emission Sources and Health Effect of PM2.5-Bound Carbonaceous Particles and Polycyclic Aromatic Hydrocarbons in the City of Kuala Lumpur, Malaysia

With increasing interest in understanding the contribution of secondary organic aerosol (SOA) to particulate air pollution in urban areas, an exploratory study was carried out to determine levels of carbonaceous aerosols and polycyclic aromatic hydrocarbons (PAHs) in the city of Kuala Lumpur, Malaysia. PM2.5 samples were collected using a high-volume sampler for 24 h in several areas in Kuala Lumpur during the north-easterly monsoon from January to March 2019. Samples were analyzed for water-soluble organic carbon (WSOC), organic carbon (OC), and elemental carbon (EC). Secondary organic carbon (SOC) in PM2.5 was estimated. Particle-bound PAHs were analyzed using gas chromatography-flame ionization detector (GC-FID). Average concentrations of WSOC, OC, and EC were 2.73 ± 2.17 (range of 0.63–9.12) µg/m3, 6.88 ± 4.94 (3.12–24.1) µg/m3, and 3.68 ± 1.58 (1.33–6.82) µg/m3, respectively, with estimated average SOC of 2.33 µg/m3, contributing 34% to total OC. The dominance of char-EC over soot-EC suggests that PM2.5 is influenced by biomass and coal combustion sources. The average of total PAHs was 1.74 ± 2.68 ng/m3. Source identification methods revealed natural gas and biomass burning, and urban traffic combustion as dominant sources of PAHs in Kuala Lumpur. A deterministic health risk assessment of PAHs was conducted for several age groups, including infant, toddler, children, adolescent, and adult. Carcinogenic and non-carcinogenic risk of PAH species were well below the acceptable levels recommended by the USEPA. Backward trajectory analysis revealed north-east air mass brought pollutants to the studied areas, suggesting the north-easterly monsoon as a major contributor to increased air pollution in Kuala Lumpur. Further work is needed using long-term monitoring data to understand the origin of PAHs contributing to SOA formation and to apply source-risk apportionment to better elucidate the potential risk factors posed by the various sources in urban areas in Kuala Lumpur.

Ultrasound-assisted magnetic solid-phase extraction of polycyclic aromatic hydrocarbons and nitrated polycyclic aromatic hydrocarbons from water samples with a magnetic polyaniline modified graphene oxide nanocomposite

A novel magnetic graphene oxide nanocomposite modified with polyaniline (Fe₃O₄@GO-PANI) was synthesized and applied for the magnetic solid-phase extraction of polycyclic aromatic hydrocarbons (PAHs) (i.e. fluorene, phenanthrene and pyrene) and nitrated polycyclic aromatic hydrocarbons (N-PAHs) (i.e. 2-nitrofluorene, 9-nitroanthracene, 1-nitropyrene and 3-nitrofluoranthene) prior to their determination by gas chromatography-mass spectrometry. The prepared nanomaterial was characterized by scanning electron microscopy, X-ray diffraction, and Fourier transform-infrared spectroscopy. The main experimental parameters affecting the extraction and desorption steps of the MSPE procedure were investigated and optimized. Under optimum conditions, coefficients of determination (r²) ranged between 0.9970 and 0.9995, limits of detection (LODs, S/N = 3) ranged between 0.04-0.05 ng mL^-1 for PAHs and 0.01-0.11 ng mL^-1 for N-PAHs, while the relative standard deviation for intra-day and inter-day repeatability were lower than 10.0% for PAHs and N-PAHs. The method was successfully applied to the analysis of tap, mineral and river water samples. Relative recoveries in spiked water samples ranged between from 91.6 to 114% and from 92.3 to 110% for PAHs and N-PAHs, respectively. The proposed method is simple, rapid, sensitive and the Fe₃O₄@GO-PANI sorbent can be reused for at least 15 times without significant decrease in extraction recovery.

Amino-based magneto-polymeric-modified mixed iron hydroxides for magnetic solid phase extraction of phenol residues in environmental samples

Mixed iron hydroxides (MIHs) modified with different amino-based polymeric materials, including aminopropyltriethoxysilane, polydopamine, diaminobenzoic acid, polyaniline, and polyphenylenediamine, were comparatively investigated as sorbents for the extraction of phenol compounds. Polyphenylenediamine-modified mixed iron hydroxides (MIH@PPDA) showed high adsorption capability for most target analytes. Its ferromagnetic behavior, with a magnetization of 17.38 emu g^-1, was sufficient for subsequent use in magnetic solid-phase extraction (MSPE). The functional groups, morphology, and magnetic properties of this magnetic nanomaterial were investigated using Fourier transform infrared spectroscopy, scanning electron microscopy, transmission electron microscopy, vibrating sample magnetometry, X-ray diffraction, and CHN analysis. High-performance liquid chromatography with a photodiode array detector was used to quantify phenol compounds. The experimental parameters affecting the efficiency of the entire MSPE process were optimized. Good linearity in the range of 0.5-1000 µg L^-1 was obtained (depended on the compound). The detection and quantitation limits varied from 0.01 to 0.3 µg L^-1 and 0.03 to 0.9 µg L^-1, respectively. The enrichment factors for all phenol compounds were in the range of 80-285. The precision in terms of intra- and inter-day relative standard deviations were below 5.8% and 6.2%, respectively. The developed MSPE method was applied to analyze phenol compounds in diverse samples, including soil, drinking water, and fruit. Relative recoveries of 76.7-130.1% were obtained. The MIH@PPDA magneto-polymeric sorbent exhibits good stability and is reliable for a variety of phenol compounds.

QuEChERS with Ultrasound-Assisted Extraction Combined with High-Performance Liquid Chromatography for the Determination of 16 Polycyclic Aromatic Hydrocarbons in Sediment

Background

Polycyclic aromatic hydrocarbons (PAHs) have attracted worldwide attention due to their carcinogenic, teratogenic, and mutagenic effects, environmental persistence, and bioaccumulation characteristics. Therefore, the sensitive, reliable, and rapid detection of PAHs in sediment is of great importance.

Objective

To develop a high-performance liquid chromatography (HPLC) with fluorescence and ultraviolet detection after Quick, Easy, Cheap, Effective, Rugged, and Safe (QuEChERS) treatment for simultaneous determination of 16 U.S. Environmental Protection Agency priority PAHs in sediment samples.

Method

The samples were ultrasonically extracted with acetone and then the supernatant was purified with a modified QuEChERS method. After centrifugation, the supernatant was injected into the HPLC system for analysis. The separation was accomplished on a ZORBAX Eclipse PAH column (150 × 4.6 mm, 3.5 μm) and the column temperature was set at 30 °C. The flow rate of the mobile phase consisting of water and acetonitrile in gradient elution mode was fixed at 0.9 mL/min. Detection was conducted on an ultraviolet detector and a fluorescence detector simultaneously. The qualitative analysis was based on retention time and the quantification was based on standard curves.

Results

Under the optimal conditions, this method showed good linearities in the range of 10–200 μg/L with correlation coefficients greater than 0.9993. The method had LODs ranging from 0.00108 to 0.314 ng/g. The mean recoveries ranged from 78.4 to 117% with intra-day and inter-day RSDs of 0.592–10.7% and 1.01–13.0%, respectively. The proposed method was successfully applied to the detection of 16 PAHs in sediment samples collected from the Funan River in Chengdu, China with total contents of 431–2143 ng/g·dw.

Conclusions

The established method is simple, rapid, environmentally friendly, and cost-effective. It can be applied to the analysis of 16 PAHs in sediment samples.

Highlights

A method of QuEChERS with ultrasound-assisted extraction combined with HPLC has been established for the analysis of 16 PAHs in sediment samples and the proposed method has been successfully applied to the analysis PAHs in real sediment samples.

A thin-layer solid-phase extraction-liquid film elution technique used for the enrichment of polycyclic aromatic hydrocarbons in water

In this article, we propose a novel microsolid-phase extraction and elution technique, which we called the thin-layer solid-phase extraction-liquid film elution technique. The thin-layer solid-phase extraction phase is an octadecylsilylated sol gel- coated porous silica thin film prepared on the outer wall of a test tube, which has a larger surface area for the extraction of the target compounds compared to a conventional solid-phase microextraction phase. After optimization of the extraction procedure for five types of polycyclic aromatic hydrocarbons, the liquid film elution technique was investigated. Liquid film elution is an elution technique wherein the compounds extracted into the thin-layer solid-phase extraction phase are eluted using a small volume of solvent film formed around the extraction phase. The results show that the elution can be carried out using 150 μL of eluent. Enrichment factors between 20 and 34 were obtained for polycyclic aromatic hydrocarbons containing more than four aromatic rings in 10 mL aliquots of aqueous samples. Finally, recoveries of 85-112% were obtained for polycyclic aromatic hydrocarbons containing more than four aromatic rings from spiked natural water samples using the thin-layer solid-phase extraction-liquid film elution technique.

Enhanced extraction of organophosphorus pesticides from fruit juices using magnetic effervescent tablets composed of the NiFe2O4@SiO2@PANI-IL nanocomposites

The reported ionic liquid (IL)-based magnetic effervescent tablets are a result of direct addition of ILs and magnetic nanoparticles (MNPs). In effervescent reaction-enhanced microextraction procedures, the dissociation between ILs and MNPs easily leads to loss of ILs due to aqueous solubility, thereby decreasing the extraction efficiency. Herein, we attached a hydrophilic IL ([BMIM]Br) onto the surface of NiFe₂O₄@SiO₂@polyaniline (NiFe₂O₄@SiO₂@PANI-IL) to prepare novel core–shell-like multi-layer nanocomposites. Magnetic effervescent tablets were composed of Na₂CO₃ as an alkaline source, tartaric acid as an acidic source and as-synthesized nanocomposites as an extractant. The nanocomposites were used in an effervescent reaction-enhanced magnetic solid-phase extraction (ERMSE) for the extraction of four organophosphorus pesticides (OPPs) in fruit juices prior to HPLC-DAD detection. Under optimized conditions, this method provided low limits of detection (0.06–0.17 μg L⁻¹), high recoveries (80.6–97.3%) and excellent precision (1.1–5.2%) for OPP quantification in five fruit juices. Notably, the three-layer core–shell nanocomposites were efficiently recycled for at least eight extraction cycles with a recovery loss of <10%. The novelty of this study lies in: (1) for the first time, the ILs-based hybrid magnetic nanocomposites were prepared with appropriate pore size/volume and more active sites for OPPs; (2) the combination of the nanocomposites with effervescent tablets realizes rapid dispersion of CO₂ bubbles, and convenient magnetic separation/collection into one synchronous step; and (3) due to there being no requirement of electrical power, it is feasible for use in field conditions. Thus, the ERMSE method has excellent potential for conventional monitoring of trace-level OPPs in complex fruit juice matrices.

The reported ionic liquid (IL)-based magnetic effervescent tablets are a result of direct addition of ILs and magnetic nanoparticles (MNPs).

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.

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.

Magnetic C60 nanospheres based solid-phase extraction coupled with isotope dilution gas chromatography-mass spectrometry method for the determination of sixteen polycyclic aromatic hydrocarbons in Chinese herbal medicines

C₆₀-based magnetic nanospheres were synthesized by coating Fe₃O₄ nanospheres with silica, then modifying with 3-aminopropyltriethoxysilane as a linker and a C₆₀ fullerene stationary phase. The morphologies, magnetic properties, infrared absorption and carbon content of magnetic nanospheres were studied by TEM, VSM, FTIR and carbon and sulfur analyzer. The magnetic nanospheres were employed for the magnetic solid-phase extraction (MSPE) of 16 polycyclic aromatic hydrocarbons (PAHs) in nine Chinese herbal medicines. The analyses were conducted by isotope dilution gas chromatography-mass spectrometry. The main parameters influencing the extraction, including extraction solvent, adsorbent amount, and extraction time were optimized. Method validation showed that the limit of detection (LOD) was 0.02-0.11 µg/kg, and the limit of quantification (LOQ) was 0.07-0.36 µg/kg. The spiked recoveries rates for 16 PAHs in white peony root were 84.7-107.2%. The relative standard deviation (RSD) was 1.7-8.4%. The established method was further used for the determination 16 PAHs in nine Chinese herbal medicines. Total content of 16 PAHs varied from 73.6 µg/kg (fructus lycii) to 2172.6 µg/kg (astragalus root). The results indicate that the pollution of PAHs in Chinese herbal medicines is serious. The established method can effective detect PAHs contamination in Chinese herbal medicines.

Facile synthesis of polydivinylbenzene coated magnetic polydopamine coupled with pressurized liquid extraction for the extraction and cleanup of polycyclic aromatic hydrocarbons in soils

Due to the trace levels of polycyclic aromatic hydrocarbons (PAHs) in soil and the complexity of soil matrices, effective sample pretreatment methods are of great significance to obtain accurate analytical results. In this paper, polydopamine (PDA) encapsulated Fe₃O₄ particles were used as seeds for in situ polymerization of divinylbenzene (DVB) to derive magnetic hybrid material Fe₃O₄@PDA@PDVB. Coupled with pressurized liquid extraction, Fe₃O₄@PDA@PDVB was investigated as a selective adsorbent for the extraction and cleanup of PAHs in soil. The prepared magnetic material was characterized and demonstrated to possess strong hydrophobicity and superparamagnetism. Under optimal conditions, Fe₃O₄@PDA@PDVB can effectively extract 15 PAHs from a 30% methanol solution within 2 min, and it is more selective for PAHs than for n-alkane in soil extracts. The matrix effect significantly decreased after extraction by the prepared material, which showed superiority to a silica gel column method (EPA 3630C Method). The developed method was linear (5-1000 ng g^-1) with coefficient of determination (R²) ranging from 0.9986-0.9998, and the limits of detection were 0.13-0.54 ng g^-1. Additionally, repetitive experiments indicated that the prepared material was reproducible and reusable with relative standard deviations below 8.4% and 8.6%, respectively. Finally, the new method was successfully employed to determine the concentrations of PAHs in genuine soil and standard reference material, and the results were comparable to those of widely utilized EPA methodology.