Synthesis of Fe3O4@PPy–MWCNT nanocomposite and its application for extraction of ultra-trace amounts of PAHs from various samples

Dispersive micro solid phase extraction of glibenclamide from plasma, urine, and wastewater using a magnetic molecularly imprinted polymer followed by its determination by a high-performance liquid chromatography-photodiode array detector

The present study describes the development of a simple and selective analytical method for dispersive micro solid phase extraction and determination of glibenclamide (GLB) using magnetic molecularly imprinted polymer (MMIP) as a sorbent. MMIP was fabricated by the non-covalent method on the surface of silicated Fe3O4 and had a high affinity for glibenclamide; dual monomers, itaconic acid and allylamine, were used for this. Polymerization was achieved by the precipitation method in the presence of glibenclamide as the template and ethylene glycol dimethacrylate as the cross-linker. The morphology and structural properties of the MMIP were characterized by different analytical methods. To achieve maximum extraction efficiency, influencing parameters were optimized. The linearity range was 1-2000 and 12-2000 μg L-1 by high-performance liquid chromatography-photodiode array detector (HPLC-PDA) and UV-vis spectroscopy, respectively. The detection and quantification limits with UV-vis and HPLC-PDA analyses were 4 and 12 μg L-1 and 0.3 and 1 μg L-1, respectively. Under optimized conditions, recovery of glibenclamide spiked in plasma, human urine, and wastewater was between 89.4 and 102.9% at the concentration levels of 25, 250, and 500 μg L-1; relative standard deviations were below 3.7% by HPLC-PDA. The developed method has a favorable pre-concentration factor of 140.0. Equilibrium data and sorption isotherms fitted well with the Langmuir model. A maximum sorption capacity of 24.260 mg g-1 was acquired based on the Langmuir model. The synthesized sorbent with high selectivity was used to separate GLB from complex biological systems and wastewater before measurement with UV-vis or HPLC-PDA.

Simultaneous remediation of polycyclic aromatic hydrocarbon and heavy metals in wastewater with zerovalent iron-titanium oxide nanoparticles (ZVI-TiO2)

The presence of polycyclic aromatic hydrocarbons (PAHs) and heavy metals (HM) in wastewater is a major challenge to the environment as various approaches have been used to remediate these contaminants from the environment. Zerovalent iron-titanium oxide nanoparticle (ZVI-TiO2 NPs) was synthesized by wet reflux in an inert environment using nitrogen gas and sodium borohydride as reducing agents. Characterization was carried out using a scanning electron microscope (SEM) coupled with electron diffraction X-ray (EDX) and Fourier transform infrared spectrophotometer (FTIR). Assessments of the wastewater were carried out with atomic absorption spectrophotometer (AAS) for HM and a gas chromatography-mass spectrophotometer (GCMS) for PAHs to determine the initial concentration (C i) compared with permissible limits of surface water and adsorption capacity with ZVI-TiO2 NPs (C f), respectively. The results obtained indicate a percentage yield of 65.51 ± 0.01 of ZVI-TiO2 NPs, with a particle size of 100 nm, weight composition of iron, titanium, and oxygen at 49.69, 5.24, and 35.41 g, respectively. FTIR shows a vibrational change of 3465, 2929, and 1641 cm−1 of OH, CH, and CO group needed for metal binding and adsorption. Remediation of HM after acid digestion gave effective removal of zinc, copper, cadmium, cobalt, and lead at an adsorption capacity of 64.29, 54.83, 53.13, 48.39, and 42.66% respectively. The adsorptions of benzo[a]pyrene, fluoranthene, pyrene, benzo[b]fluoranthene, and perylene were 77.87, 67.85, 52.17, 29.50, and 25.45%, respectively. These results indicate that metal/metal oxide (ZVI-TiO2) nanoparticles have a high potential in the remediation of heavy metals and PAHs from the water ecosystem.

Fabric phase sorptive extraction combined with gas chromatography-mass spectrometry as an innovative analytical technique for the determination of selected polycyclic aromatic hydrocarbons in herbal infusions and tea samples

This study presents a fabric phase sorptive extraction (FPSE) protocol for the isolation and preconcentration of four selected polycyclic aromatic hydrocarbons from tea samples and herbal infusions, followed by their separation and quantification by gas chromatography-mass spectrometry (GC-MS). In FPSE, extraction of the target analytes is performed utilizing a flexible fabric substrate that is coated with a highly efficient sol–gel sorbent. In this work, eighteen different FPSE membranes were examined, with the highest extraction recoveries being observed with the sol–gel C₁₈ coated FPSE membrane. The main parameters that influence the adsorption and desorption of the PAHs were optimized and the proposed method was validated. The detection limits and the quantification limits were 0.08–0.17 ng mL⁻¹ and 0.25–0.50 ng mL⁻¹, respectively, for the different target compounds with a 10 mL sample. The relative standard deviations for intra-day and inter-day repeatability were less than 7.9% and 8.5%, respectively. The sol–gel C₁₈ coated FPSE membrane could be used for at least 5 subsequent sample preparation cycles. Finally, the proposed protocol was successfully employed for the determination of PAHs in a wide range of tea and herbal infusion samples.

A fabric phase sorptive extraction (FPSE) protocol for the isolation and preconcentration of four selected polycyclic aromatic hydrocarbons from tea samples and herbal infusions is presented, followed by their quantitative analysis by GC-MS.

Magnetic porous carbon nanocomposite derived from cobalt based-metal-organic framework for extraction and determination of homo and hetero-polycyclic aromatic hydrocarbons

Herein, a novel magnetic porous carbon nanocomposite derived from a cobalt based-metal-organic framework was synthesized and evaluated for simultaneous preconcentration of homo and hetero-polycyclic aromatic hydrocarbons. Briefly, magnetite nanoparticles (MNPs) were synthesized and then were coated with a metal-organic framework layer. Finally, the magnetic nanocomposite was carbonized under an inert atmosphere to obtain the magnetic porous carbon (MPC). Various characterization techniques such as FT-IR spectroscopy, transmission and scanning electron microcopies, vibrating sample magnetometry, and X-ray diffraction were employed. Applicability of the MPC was explored using benzothiophene, dibenzothiophene, 9,10-dimethylanthracene, and benz[α]anthracene as the model analytes. Limits of detection and linearities were achieved in the range of 0.06-0.18 μg L^-1 and 0.25-500 μg L^-1, respectively. Precision of the method as RSDs was evaluated which was in the range of 4.2-7.0% (within-day, n = 5) and 8.2-11.3% (between-day, n = 3). Ultimately, the method was applied to analyze two seawater samples and satisfactory results (RSDs%, 5.0-9.0%; relative recoveries, 89-104%) were obtained.

3D flower-liked Fe3O4/C for highly sensitive magnetic dispersive solid-phase extraction of four trace non-steroidal anti-inflammatory drugs

A low cost-effective and simple synthesis method was adopted to acquire three-dimensional flower-like structure Fe₃O₄/C that has large specific area, suitable pore structure and sufficient saturation magnetism. The obtained Fe₃O₄/C exhibits outstanding preconcentration ability and was applied to extracting non-steroidal anti-inflammatory drugs from complex environmental and biological samples. The parameters of magnetic solid-phase extraction were optimized by univariate and multivariate methods (Box-Behnken design). The high degree of linearity from 2.5 to 1000.0 ng mL^-1 (R² ≥ 0.9976), the limits of detection from 0.25 to 0.5 ng mL^{- 1} (S/N = 3), and the limits of quantitation from 1.0 to 2.0 ng mL^{- 1} (S/N = 10) were yielded by adopting this novel method after the optimization. Moreover, the recoveries of non-steroidal anti-inflammatory drugs from 89.6 to 107.0% were acquired in spiked plasma, urine and lake samples. In addition, the adsorption of non-steroidal anti-inflammatory drugs on Fe₃O₄/C was explored by adsorption isotherms and kinetic studies. Furthermore, the adsorption mechanism for non-steroidal anti-inflammatory drugs by Fe₃O₄/C was proposed, which was hydrogen bonding and π-π interaction between non-steroidal anti-inflammatory drugs and Fe₃O₄/C. Graphical abstract.

Magnetic Polydopamine Modified with Choline-Based Deep Eutectic Solvent for the Magnetic Solid-Phase Extraction of Sulfonylurea Herbicides in Water Samples

A novel magnetic solid-phase extraction technique coupled to ultraperformance liquid chromatography has been developed for separation and preconcentration of four sulfonylurea herbicides (sulfosulfuron, bensulfuron-methyl, pyrazosulfuron-ethyl and halosulfuro-methyl) in aqueous samples. The key point of this method was the application of a novel magnetic nanomaterial that composed of a low eutectic solvent as a shell coated on the magnetic core modified by polydopamine. The extensive active sites outside the low eutectic solvent can effectively adsorb the target herbicide in the extraction process. The obtained magnetic adsorbent was characterized with fourier transform infrared spectrometry, scanning electron microscopy and vibrating sample magnetometer. The influence parameters relevant to this method were optimized. Under the optimum conditions, good linearities could be obtained within the range of 1.0-200 μg L-1 for all analytes, with correlation coefficients ≥0.9908. The limit of detections of the method was between 0.0074 and 0.0100 μg L-1 and the relative standard deviations were 1.1-3.6%. The enrichment factor is 66.6. In the final experiment, the proposed method was successfully applied to the analysis of sulfonylurea herbicides residue in environment and drinking-water samples, and the obtained recoveries were between 70.6% and 109.4%.

Application of magnetic nanomaterials in magnetic in-tube solid-phase microextraction

Development of magnetic nanomaterials has greatly promoted the innovation of in-tube solid-phase microextraction. This review article gives an insight into recent advances in the modifications and applications of magnetic nanomaterials for in-tube solid-phase microextraction. Also, different magnetic nanomaterials which have recently been utilized as in-tube solid-phase microextraction sorbents are classified. This study shows that magnetic nanomaterials have gained significant attention owing to large specific surface area, selective absorption, and surface modification. Magnetic in-tube solid-phase microextraction has been applied for the analysis of food samples, biological, and environmental. However, for full development of magnetic in-tube SPME, effort is still needed to overcome limitations, such as mechanical stability, selectivity and low extraction efficiency. To achieve these objectives, research on magnetic in-tube SPME is mainly focused in the preparation of new extractive phases.

Solid-Phase Microextraction Arrow for the Sampling of Volatile Organic Compounds in Milk Samples

A novel sample preparation method based on the use of the Arrow solid-phase microextraction device was used to extract and preconcentrate volatile organic compounds (VOCs) from milk samples prior to their determination by gas chromatography–mass spectrometry (GC-MS). The experimental parameters of the solid-phase microextraction (SPME) Arrow method were evaluated in terms of fiber type, sample volume, extraction temperature, extraction time, stirring rate and salt addition. Under the optimum extraction conditions, the SPME Arrow was compared with conventional SPME fibers to evaluate the effectiveness of the SPME Arrow method. Evaluation of the conventional SPME procedure was also performed under optimized conditions, for appropriate method comparison. Due to the larger sorption phase volume of SPME Arrow, a higher sensitivity and reproducibility were observed for the determined chromatographic peaks in comparison with conventional SPME fibers. The use of Carbon wide range (WR) SPME Arrow/polydimethylsiloxane (CAR/PDMS) SPME Arrow fibers leads to a compound-dependent improvement of a factor of 4–5x over the classical SPME setup. Moreover, the relative standard deviation (RSD) of the total volatiles for a conventional SPME procedure was 12.5%, while for SPME Arrow it was 6.2%. Finally, the novel method was successfully employed for the analysis of commercially available milk samples. The findings of this study indicate that SPME Arrow can be effectively used for the determination of volatile organic compounds in complex food matrixes.

Preparation of gold nanorod-incorporated monolith for solid phase extraction of polycyclic aromatic hydrocarbons

An organic-inorganic hybrid monolithic column doped with gold nanorods (AuNRs) was prepared and evaluated for solid phase extraction (SPE) of polycyclic aromatic hydrocarbons (PAHs). Excellent dispersibility of AuNRs in binary green porogen system consisting of 1-hexyl-3-methylimidazolium tetrafluoroborate and deep eutectic solvents (DESs) was confirmed by energy dispersive spectrometry (EDS). The particle size of the resulting AuNRs (70-90 nm) was thoroughly examined by a transmission electron microscopy (TEM). The redox system including ammonium persulfate (APS) and tetramethylethylenediamine (TEMED) was used to initiate in situ polymerization at 4 °C to prepare the hybrid monolith. The mesoporous structure of the AuNR hybrid monoliths was confirmed by scanning electron microscopy (SEM) and nitrogen adsorption. With enrichment factors (EFs) of 150- to 292-fold, the developed method was successfully applied to the determination of 10 PAHs in wastewater samples. The recoveries at a spiked level were in the range 84.9 to 99.5% with limit of detections (LODs) and relative standard deviations (RSDs) ranging from 0.02 to 0.10 μg L^-1 and 1.5 to 4.2%, respectively. The correlation coefficients (R²) for the calibration function obtained were better 0.9991 for the target compounds. Compared to the AuNR-free monolith, the extraction efficiency of the AuNR-incorporated monolith is more than two times higher. The results indicated that the doping of AuNRs is an effective approach to obtain the hybrid monolithic column with good separation ability for PAHs. Graphical abstract.

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.

Nanoparticles Used for Extraction of Polycyclic Aromatic Hydrocarbons

This article offers a review on the application of nanoparticles (NPs) that have been used as sorbents in the analysis of polycyclic aromatic hydrocarbons (PAHs). The novel advances in the application of carbon NPs, mesoporous silica NPs, metal, metal oxides, and magnetic and magnetised NPs in the extraction of PAHs from matrix solutions were discussed. The extraction techniques used to isolate PAHs have been highlighted including their advantages and limitations. Methods for preparing NPs and optimized conditions of NPs extraction efficiency have been overviewed since proper extraction procedures were necessary to achieve optimum analytical results. The aim was to provide an overview of current knowledge and information in order to assess the need for further exploration that can lead to an efficient and optimum analysis of PAHs.

Simultaneous determination of steroid drugs in the ointment via magnetic solid phase extraction followed by HPLC-UV

The copper-coated iron oxide nanoparticles with core-shell were produced by deposition of a Cu shell on Fe₃O₄ NPs through reduction of Cu²⁺ ions in solution using NaBH₄. Subsequently, the organosulfur compound, bis-(2,4,4-trimethylpentyl)-dithiophosphinic acid (b-TMP-DTPA), was used to form self-assembled monolayer in order to modify sorbent's surface via covalent bonding between Cu and thiol (–SH) terminal groups. The prepared magnetic nanoparticles were characterized by using Fourier transform infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM), transmission electron microscope (TEM), vibrating sample magnetometer (VSM) and thermo gravimetric analysis (TGA). Then, the application of this new sorbent was investigated to extract the steroid drugs in ointment samples with the aid of ultrasound. An external magnetic field was applied to collect the magnetic nanoparticles (MNPs). The extracted analytes were desorbed using acetonitrile. The obtained extraction solution was analyzed by HPLC-UV. The main affecting factors on the extraction efficiency including pH, sonication time, amount of sorbent, salt concentration, and desorption conditions were optimized in detail. Under the optimum conditions, good linearity was obtained in the range of 2.5–250.0 µg/ L with reasonable linearity (R² > 0.99) and the limits of detection (LODs) ranged between 0.5 and 1.0 µg/L (based on S/N = 3). Repeatability (intra-day precision) based on five replicates and preconcentration factors were calculated to be 3.6%–4.7% and 87–116, respectively. Relative recoveries in ointment samples at two spiked levels of the target analytes were obtained in the range of 90.0%–103.2%. The results illustrated that the Fe₃O₄@Cu@ b-TMP-DTPA NPs have the capability of extraction of steroid drugs from ointment samples.