Urinary biomonitoring of fuel ether oxygenates using a needle trap device packed with a novel molecularly imprinted polymer surface modified Zeolite Y.

This study introduces an innovative needle trap device (NTD) featuring a molecularly imprinted polymer (MIP) surface-modified Zeolite Y. The developed NTD was integrated with gas chromatography-flame ionization detector (GC-FID) and employed for analysis of fuel ether oxygenates (methyl tert­butyl ether, MTBE, ethyl tert­butyl ether, ETBE, and tert­butyl formate, TBF) in urine samples. To optimize the key experimental variables including extraction temperature, extraction time, salt concentration, and stirring speed, a central composite design-response surface methodology (CCD-RSM) was employed. The optimal values for extraction in the study were found to be 51.2 °C extraction temperature, 46.2 min extraction time, 27 % salt concentration, and 620 rpm stirring speed. Under the optimized conditions, the calibration curves demonstrated excellent linearity within the range of 0.1-100 µg L-1, with correlation coefficients (R2) exceeding 0.99. The limits of detection (LODs) for MTBE, ETBE, and TBF were obtained 0.06, 0.08, and 0.09 µg L-1, respectively. Moreover, the limits of quantification (LOQs) for MTBE, ETBE, and TBF were obtained 0.18, 0.24, and 0.27 µg L-1, respectively. The enrichment factor was also found to be in the range of 98-129.The NTD-GC-FID procedure demonstrated a high extraction efficiency, making it a promising tool for urinary biomonitoring of fuel ether oxygenates with improved sensitivity and selectivity compared to current methods.

Easy and fast synthesis of MnCo-LDH yolk-shell spheres porous composites applied electrospinning nanofibers highly effective for extracting triazole fungicides.

Today, the wide utilization of triazole fungicides due to environmental damage and its side effects has raised global concern. Thus, in this investigation, polyacrylonitrile/MnCo-layered double hydroxides nanofiber was synthesized and applied as an effective and novel adsorbent at thin-film solid-phase micro-extraction technique for the quick and concurrent extraction of five triazole fungicides in fruit and vegetable samples before quantitative analysis by high-performance liquid chromatography-ultraviolet. The incorporation of MnCo-layered double hydroxides with porous structure and abundant functional groups in a polymer medium improves the extraction efficiency of nanofibers owing to hydrogen bonding and π-π interactions formed between analytes and synthesized nano-adsorbent. Various important elements that affect the extraction efficiency of the intended analytes were optimized using a time-variable approach. Under the optimum conditions, the limit of detection and quantification range from 0.1 to 0.15 and 0.3-0.5 ng mL-1, respectively.

Quick synthesis of CoFe-PBA@GO with electrochemical method as a novel, sensitive, and degradable nanocomposite applied in nanofibers for triazole extraction before HPLC-UV analysis.

Today, the wide use of triazole fungicides due to environmental damage and its side effects has raised global concern. Hence, in this research, poly-vinyl alcohol/polyacrylic-acid/CoFe-PBA@GO electrospun nanofiber was synthesized and applied as effective, degradable, and novel adsorbent at pipette-tip microextraction (PT-µSPE) method for the rapid and concurrent extraction of five of triazole fungicides in fruit and vegetable samples prior to quantitative analysis by high-performance liquid chromatography-ultraviolet. The incorporation of CoFe-PBA@GO with superporous structure and abundant functional groups in a polymer medium improves the extraction efficiency of nanofibers due to hydrogen bonding and π-π interactions formed between analytes and synthesized nano-adsorbent. Various important elements that affect the extraction yield of the target analytes were optimized utilizing a time-variable approach. Under the optimum conditions, dynamic range was attained in the range of 0.3-900.0 ng/mL with correlation coefficients ≥ 0.999. The identification limit of the PT-µSPE-HPLC-UV method ranged from 0.1 to 0.3 ng/mL.

A novel sorbent based on electrospun for electrically-assisted solid phase microextraction of six non-steroid anti-inflammatory drugs, followed by quantitation with HPLC-UV in human plasma samples.

BACKGROUND: Although NSAIDs possess notable therapeutic and pharmaceutical qualities, it's essential to acknowledge that excessive doses can result in toxicity within the human body. Moreover, the importance lies in identifying and measuring their trace amounts. Due to their existence within intricate matrices, the creation of novel electrospun nanofibers as sorbents for electrically-assisted solidphase microextraction (EA-SPME) becomes vital. This innovation caters to the requirement for the effective pre-treatment of NSAID samples, providing a strategic approach to managing the complexities associated with trace quantities found in various matrices. RESULTS: First, polyvinylalcohol/casein/tannic acid/polyaniline/titanium dioxide nanoparticles (PVA/CAS/TA/PANI/TiO2 NPs) electrospun nanofibers were prepared for EA-SPME on pewter rode and then, trace amounts of six NSAIDs (Acetaminophen, Caffeine, Naproxen, Celecoxib, Ibuprofen and mefenamic acid) were adsorbed chemically on these nanofibers. In the next step, the desorption of six NSAIDs was electrochemically done from prepared electrospun nanofibers on a pewter rod which was as working electrode at three electrodes system. Finally, these drugs were quantified from different human plasma samples with HPLC-UV. The synthesis of electrospun nanofibers was confirmed through a series of analytical techniques including field emission-scanning electron microscopy (FE-SEM), energy-dispersive X-ray spectroscopy with elemental mapping analysis (EDX-Mapping), X-ray diffraction (XRD), and Fourier transform-infrared (FT-IR). The optimal percentage of additive compounds to PVA/CAS for electrospinning, as well as the factors influencing adsorption and desorption processes, were determined through both of Design Expert software and MATLAB programming language. SIGNIFICANCE: Under optimum conditions, the wide linear range was 27-8000 ng mL-1 with R2≥ 0.9897, low detection limits were ranged from 8 to 27.3 ng mL-1 based on S/N = 3 and significant enrichment factors were acquired. The intra-day and inter-day RSDs% were obtained within the 4.51% - 5.68% and 4.28%-5.45%, respectively. Finally, The effectiveness of the EA-SPME-HPLC-UV method was assessed for determining NSAIDs in plasma samples, demonstrating good recoveries ranging from 90.2% to 105.2%.

Comparative study of molecularly imprinted polymer surface modified magnetic silica aerogel, zeolite Y, and MIL-101(Cr) for dispersive solid phase extraction of fuel ether oxygenates in drinking water.

The study was performed in two phases. First, the polymerization was carried out upon three magnetized surfaces of silica aerogel, zeolite Y, and MIL-101(Cr). Then, optimal molecularly imprinted polymer and optimal extraction conditions were determined by the central composite design-response surface method. Subsequently, the validation parameters of dispersive solid-phase extraction based optimal molecularly imprinted polymer were examined for the extraction of the fuel ether oxygenates. The optimal conditions include the type of adsorbent: Zeolite-magnetic molecularly imprinted polymer, the amount of adsorbent: 40 mg, pH: 7.7, and absorption time: 24.8 min which was selected with desirability equal to 0.996. The calibration graphs were linear between 1 and 100 µg L-1, with good correlation coefficients. The limits of detection were found to be 0.64, 0. 4, and 0.34 µg L-1 for methyl tert-butyl ether, ethyl tert-butyl ether, and tert butyl formate, respectively. The method proved reliable for analyzing fuel ether oxygenates in drinking water.

A green QuEChERS syringe filter based micro-solid phase extraction using hydrophobic natural deep eutectic solvent as immobilized sorbent for simultaneous analysis of five anti-diabetic drugs by HPLC-UV.

BACKGROUND: Here, it has been discussed about creating a specific and sustainable analytical technique for monitoring anti-diabetic drugs in order to accurately determine the dosage in patients and reduce side effects, remove them from wastewater (as emerging contaminants), and ultimately abate pharmaceutical pollutants in the environment. RESULTS: In this research, a green and reproducible Quick Easy Cheap Effective Rugged Safe (QuEChERS) method based on syringe filter based micro-solid phase extraction (SF-µSPE) coupled with HPLC-UV using a green sorbent was developed and optimized for the extraction of five anti-diabetic drugs from wastewater, serum, and plasma real samples. A novel green sorbent composed of a liquid mixture of thymol: menthol ([Thy]:[Men], 1:1) hydrophobic natural deep eutectic solvent (HNADES) and curcumin (Cur) immobilized into the non-toxic and biodegradable polyvinyl alcohol (PVA) electrospun nanofibers' mat was synthesized simply via cheap equipment. Cur was added to enhance the hydrophobicity and functionality of the sorbent. The immobilization process was performed by soaking the mat in the liquid mixture for a specific duration. The correct synthesis and experimental molar ratio of the HNADES components were confirmed by ATR-FTIR and NMR (1H and 13C) spectroscopy. The prepared green sorbent (Cur-HNADES/PVA) was characterized using ATR-FTIR, FE-SEM, EDX/EDX mapping analysis, and water contact angle (WCA) measurement, and it exhibited satisfactory adsorption capacity for the target analytes. SIGNIFICANCE: Under optimal conditions (pH = 6.0, adsorption cycle = 3, sample volume = 5.0 mL, desorption cycle = 1, type and volume of elution = 80:20 %v/v MeOH/ACN and 500.0 µL), the method was validated in terms of specificity, linear dynamic ranges (LDRs = 0.1-2000.0 µg L-1 and 0.1-1800.0 µg L-1), limits of detection (LODs = 0.03-0.09 µg L-1), and precision (within-day RSDs% = 0.32-1.45% and between-day RSDs% = 0.59-2.03%). Evaluation of the greenness aspects of the proposed method was accomplished using the Green Analytical Procedure Index (GAPI) and Analytical GREEnness (AGREE) approaches. It is noteworthy that the conducted research represents the first report of the synthesis and application of this novel and green sorbent for the determination of anti-diabetic drugs in the mentioned real samples.

Polyvinyl alcohol/citric acid/ß-cyclodextrin/CuONP composite nanofibers as an effective and green absorbent for the simultaneous extraction of three antidepressant drugs in biological fluids prior to GC-FID analysis.

Composite nanofibers, namely, polyvinyl alcohol (PVA), citric acid (CA), ß-cyclodextrin (ß-CD), and copper oxide nanoparticles (PVA/CA/ß-cyclodextrin/CuO NPs), were developed as a novel, green, and efficient adsorbent in the pipette tip-micro-solid-phase extraction method (PT-µSPE), for the simultaneous extraction of three antidepressants drugs namely imipramine (IMP), citalopram (CIT), and clozapine (CLZ) in biological fluids before quantification by gas chromatography (GC-FID). Based on the obtained results from field emission scanning electron microscopy (FE-SEM), energy-dispersive X-ray spectroscopy (EDX), Fourier transform infrared spectroscopy (FT-IR), and X-ray diffraction (XRD), the successful synthesis of composite nanofibers was approved. Due to the presence of ß-cyclodextrins and CuO NPs rich of functional groups on their surface, the nanofibers have high extraction efficiency. Under the optimal conditions, the linear range for imipramine, citalopram, and clozapine was 0.1 to 1000.0 ng mL-1 with a determination coefficient ≥ 0.99. The limits of detection (LODs) were in the range 0.03 to 0.15 ng mL-1. The relative standard deviation was 4.8 to 8.7% (within-day, n = 4) and 5.1 to 9.2% (between-day, n = 3) for 3 consecutive days. In addition, excellent clean-up was achieved which is a great advantage over other sample preparation methods. Finally, the ability of the developed method to extract the target analytes from the biological samples was evaluated.

Electrospun composite nanofibers modified with silver nanoparticles for extraction of trace heavy metals from water and rice samples: An highly efficient and reproducible sorbent.

Herein, a composite of polyacrylonitrile (PAN)/agar/silver nanoparticles (AgNPs) electrospun nanofibers was fabricated and applied as an efficient sorbent for thin-film micro-extraction (TFME) of five metal ions followed by inductively coupled plasma optical emission spectroscopy (ICP-OES). Incorporating agar into the nanofibers followed by in situ photo-reductive reaction under UV-lamp resulted in highly uniform dispersion of AgNPs in the nanofibers. Under the optimized conditions, agreeable linearity was acquired in the range of 0.5-250.0 ng mL-1 (R2 ≥ 0.9985). The LODs (based on S/N = 3) were attained in the range of 0.2 to 0.5 ng mL-1. The relative standard deviations (RSDs) were between 4.5% and 5.6% (intra-day, n = 5) and 5.3%-5.9% (inter-day, n = 3) for three sequential days. The developed method was investigated with water and rice samples, and recoveries (93.9-98.0%) indicated that the PAN/agar/AgNPs could be a promising film for the adsorption of heavy metal ions in varied samples.

Development of electrospun nanofibers based on Poly (vinyl alcohol) for thin film solid-phase microextraction of antidepressant drugs in biological samples.

Today, antidepressants are widely used and it is important to determine their trace amounts due to harmful consequences. Here, a new nano sorbent was reported for the simultaneous extraction and determination of three types of antidepressant drugs (Clomipramine (CLO), Clozapine (CLZ), and Trimipramine (TRP) by the thin-film solid-phase micro-extraction (TFME-µSPE) method followed by the Gas Chromatography-flame ionization detector (GC-FID) analysis. So, the compound poly (vinyl alcohol) (PVA)/citric acid(CA)/ß-cyclodextrin/Bi2S3@g-C3N4 nano sorbent was constructed by electrospinning technique. Then, nano sorbent was studied to optimize the many parameters impacting the extraction performance. Electrospun nanofiber has a large surface area, high porosity, and homogeneous morphology with a uniform bead-free structure. In optimal conditions, the limits of detection and quantification were calculated to be 0.15-0.03 ng mL-1 and 0.5-0.1 ng mL-1, respectively. The dynamic linear range (DLR) was in the range of 0.1 to 1000 ng mL-1 for CLO and CLZ, and 0.5 to 1000 ng mL-1 for TRP with correlation coefficients (R2) of 0.999. The relative standard deviations (RSDs) were achieved in the range of 4.9-6.8% (intra-day, n = 4) and 5.4-7.9% (inter-day, n = 3) in the period of 3 days. Finally, the capability of the method was evaluated to simultaneously measure trace amounts of antidepressants aqueous sample with desirable extraction efficiency (78 to 95%).

Application of electrospun composite nanofibers as an efficient sorbent for extraction of pesticides from food samples.

Herein, the composite of polylactic acid (PLA)/ Iron-based metal-organic framework (r-MIL-88A)/ Cellulose electrospun nanofibers was fabricated; and then, applied as a novel sorbent for thin-film micro-extraction (TFME) of four selected pesticides followed by GC-FID analysis. From the evaluation of scanning electron microscopy, Fourier transform infrared spectroscopy energy dispersive X-ray spectroscopy and X-ray diffraction, the successful fabrication of composite nanaofibers was approved. The presence of r-MIL-88A/Cellulose with large surface area and plenty of OH-functional groups results in improving PLA extraction efficiency. The effect of various main parameters on extraction efficiency was evaluated. The LODs (based on S/N = 3) were in the range of 1.0 to 1.5 ng mL-1. Intra-day and inter-day relative standard deviations (RSDs) were in the range of 4.8% - 5.6% and 5.2%-6.4%, respectively. In addition, the fiber to fiber relative standard deviations were observed in the range of 5.2%-12.3%. By using the optimized factors, acceptable linearity ranges were obtained in the range of 3.0-1900.0 ng mL-1 for metribuzin and ethofumasate, and 5.0-2000.0 for atrazine and ametryn (R2 = 0.9913-0.9967). The developed method was investigated in fruit juice, vegetables, milk and honey samples, and recoveries (79.3-95.6%) indicate that the PLA/r-MIL-88A/Cellulose can be a prominent composite film for the extraction of the target analytes in various samples.

PVA/Stevia/MIL-88A@AuNPs composite nanofibers as a novel sorbent for simultaneous extraction of eight agricultural pesticides in food and vegetable samples followed by HPLC-UV analysis.

Herein, an electrospun composite from poly(vinyl alcohol) (PVA) and Stevia extract as a cross-linked nanofibrous was prepared with incorporating Fe-metal organic framework@Au nanoparticles (MIL-88A@AuNPs). The final composite was characterized, and then used as an efficient sorbent in pipette-tip micro solid-phase extraction (PT-µSPE) of eight selected pesticides in food samples followed by HPLC-UV analysis. Under the opted conditions, the linearity was in the range of 1.0-1000.0 ng mL-1 for atrazine and ametryn, 3.0-1500.0 ng mL-1 for tribenuron-methyl, metribuzin, profenofos and chlorpyrifos, 5.0 to 1500.0 ng mL-1 for phosalone, and 5.0-2000.0 ng mL-1 for malation with coefficient of determination (r2) ≥ 0.9943. The LODs (based on S/N = 3) ranged from 0.3 to 1.5 ng m L-1. The relative standard deviations (RSDs) were between 5.2% and 6.6% (intra-day, n = 5) and 5.9%-7.4% (inter-day, n = 3) for three consecutive days. Ultimately, the capability of the method in various food samples was appraised with good recoveries (79.3 to 97.6%).

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.

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.

Simultaneous trace-level monitoring of seven opioid analgesic drugs in biological samples by pipette-tip micro solid phase extraction based on PVA-PAA/CNT-CNC composite nanofibers followed by HPLC-UV analysis.

Electrospun poly(vinyl alcohol)-(PVA)-poly(acrylic acid) (PAA)/carbon nanotubes(CNTs)-cellulose nanocrystal (CNC) (PVA-PAA/CNT-CNC) composite nanofibers were prepared and characterized using Fourier transform-infrared spectroscopy and field emission scanning electron microscopy. The resultant composite was used as an effective and novel sorbent for pipette-tip micro-solid phase extraction (PT-µSPE) of seven opioid analgesics (OAs) in biological samples followed by HPLC-UV analysis. Addition of CNT-CNC with the high specific surface area and plenty of OH-functional groups endows the nanofibers with considerable extraction efficiency. Under the optimum conditions, the linearity was obtained in the range 1.5 to 700.0 ng mL-1 for morphine, codeine, oxycodone, and tramadol, and 0.5 to 1000.0 ng mL-1 for nalbuphine, thebaine, and noscapine with coefficient of determination (r2) ≥ 0.9990. Detection limits (LODs) based on S/N = 3 were in the range of 0.15-0.50 ng mL-1. The relative standard deviations (RSDs) of 4.1-5.4% (intra-day, n = 5) and 5.2-6.4% (inter-day, n = 3) for three consecutive days were achieved. Finally, the efficiency of the PT-µSPE-HPLC-UV method was evaluated for the determination of OAs in human plasma and urine samples with good recoveries (87.3 to 97.8%). A: Schematic illustration for the preparation of PVA-PAA/CNT-CNC composite nanofibers. B: Schematic presentation of applying PVA-PAA/CNT-CNC composite nanofibers as the sorbent in pipette-tip micro solid-phase extraction (PT-µSPE) for the preconcentration of seven opioid analgesic drugs in biological samples before HPLC-UV analysis.

Application of electrospun polyacrylonitrile/Zn-MOF-74@GO nanocomposite as the sorbent for online micro solid-phase extraction of chlorobenzenes in water, soil, and food samples prior to liquid chromatography analysis.

An online micro solid-phase extraction (online-µSPE) using electrospun nanofibers, as an efficient sorbent, was developed to extract chlorobenzenes (CBs) from paddy soil, agricultural wastewater, and food samples (fruit juices, vegetables, rice samples) followed by high performance liquid chromatography analysis. Electrospun nanofibers were fabricated using a nanocomposite containing polyacrylonitrile and Zn-metal organic framework 74 @graphene oxide (PAN/Zn-MOF-74@GO), and subsequently characterized. Under the optimal conditions, acceptable linearity was obtained in the range of 0.25-700.00 ng mL-1 for 1,2-dichlorobenzene (1,2-DCB) and 2.50-700.00 ng mL-1 for both 1,2,3-trichlorobenzene (1,2,3-TCB) and 1,2,4-trichlorobenzene (1,2,4-TCB) with determination coefficients ≥ 0.9991. The limits of detection ranged from 0.08 to 1.10 ng mL-1. The intra-day and inter-day single fiber and fiber to fiber relative standard deviations were observed in the range of 4.1%-9.5% and 5.8%-12.1%, respectively. The performance of this method was examined by determining the target analytes in the different spiked samples.

Preparation of Polyacrylonitrile/Ni-MOF electrospun nanofiber as an efficient fiber coating material for headspace solid-phase microextraction of diazinon and chlorpyrifos followed by CD-IMS analysis.

Herein, an electrospun polyacrylonitrile/nickel-based metal-organic framework nanocomposite (PAN/Ni-MOF) coating on a stainless steel wire was synthesized and employed as a novel nanosorbent for headspace solid-phase microextraction (HS-SPME) of organophosphorus pesticides (OPPs), diazinon (DIZ), and chlorpyrifos (CPS) from the diverse aqueous media followed by corona discharge ion mobility spectrometry (CD-IMS). Under the optimum experimental conditions, the calibration plots were linear in the range of 1.0-250.0 ng mL-1 for DIZ and 0.5-300.0 ng mL-1 for CPS with r2 > 0.999. The detection limits (S/N = 3) were 0.3 and 0.2 ng mL-1 for DIZ and CPS, respectively. The intra-day relative standard deviations (RSDs%) (n = 5) at the concentration levels of 20.0, 40.0, and 100.0 ng mL-1 were ≤ 5.2%. To investigate the extraction efficiency, PAN/Ni-MOF was employed to analyze various juice samples, including orange, apple, and grape juices, and in three water samples where it led to good recoveries ranged between 87% and 98%.

A novel polymer coated magnetic porous carbon nanocomposite derived from a metal-organic framework for multi-target environmental pollutants preconcentration.

This study describes the synthesis of a novel polymer (polypyrrole-polythiophene) coated magnetic porous carbon (MPC) composite derived from magnetic metal-organic framework (MOF) and its utilization in multi-target environmental pollutants preconcentration. In this regards, Fe3O4 nanoparticles (NPs) was used as magnetic core and Co-MOF-71 was coated on the surface of the NPs. Afterwards, magnetic MOF (MMOF) was carbonized under nitrogen atmosphere and finally MNC was coated with a polymer layer of the type polypyrrole-polythiophene to obtain the nanocomposite (MPC@PPy-PTh). Magnetic property, structure and morphology of MPC@PPy-PTh were explored via various characterization techniques. Applicability of MPC@PPy-PTh nanoadsorbent was investigated in multi-target environmental pollutants preconcentration using 4-chlorophenol 2-naphtol, 1-amino-2-naphthol, 2,4-dichloroaniline, 3,4-dichloroaniline, benzothiophene and naphthalene as the model analytes. Effect of experimental factors on the preconcentration of target pollutants was explored and optimized systematically. Under the optimized condition, LODs were obtained in the range of 0.06-0.18 µg L-1. The proposed method exhibited linearity within the range of 0.25-500 µg L-1. Repeatability of the new method based on the relative standard deviations (n = 5) was in the range of 3.4-9.0%. Finally, the analytical applicability of the optimized method was investigated in seawater and wastewater samples and satisfactory results were achieved.

Use of aloin-based and rosin-based electrospun nanofibers as natural nanosorbents for the extraction of polycyclic aromatic hydrocarbons and phenoxyacetic acid herbicides by microextraction in packed syringe method prior to GC-FID detection.

The synthesis of three kinds of sorbents is described. The first kind was a hydrophobic nanofiber as a specific sorbent for non-polar compounds. The second one was a hydrophilic nanofiber as a specific sorbent for polar compounds and the third one was a generic sorbent synthesized from hydrophilic and hydrophobic compounds. The functional groups were natural compounds extracted from aloin plant and gum of pine tree. The aloin/polyacrylonitrile (PAN), rosin/PAN, and aloin/rosin/PAN electrospun nanofibers were synthesized through electrospinning strategy and then characterized using field emission scanning electron microscopy and Fourier transform infrared spectroscopy. Thereafter, the synthesized sorbents were used in microextraction using the packed syringe (MEPS) method. The determination was conducted using gas chromatography with flame ionization detection (GC-FID). Under the optimum condition, the method using aloin/rosin/PAN nanofibers as a sorbent showed a good linearity in the range 1.0-250 ng mL-1 for polycyclic aromatic hydrocarbons (PAHs) (as a model for non-polar compounds) and 1.0-200 ng mL-1 for phenoxyacetic acid herbicides (CAPs) (as a model for polar compounds) with correlation coefficient (R2) higher than 0.997. Limits of detections (LODs) for PAHs and CAPs were in the range 0.1-0.3 ng mL-1 and 0.3-0.5 ng mL-1, respectively. The intra-day (n = 3) and inter-day (between 3 days) relative standard deviations (RDSs%) were in the range 6.3-12.3% for a single syringe. Finally, the MEPS-GC-FID method was applied as a simple, facile, and time and cost-effective method to analyze environmental, farm, and industrial water samples. Graphical abstract Herein, aloin/rosin/polyacrylonitrile (PAN) electrospun nanofiber was successfully synthesized and applied as a sorbent for extraction of polycyclic aromatic hydrocarbons (PAHs) as non-polar compounds and phenoxyacetic acid herbicides (CPAs) as polar compounds from aqueous solutions before GC-FID analysis.

Polyacrylonitrile/MIL-53(Fe) electrospun nanofiber for pipette-tip micro solid phase extraction of nitrazepam and oxazepam followed by HPLC analysis.

Nanofibers were prepared from a nanocomposite consisting of polyacrylonitrile and a metal-organic framework of type MIL-53(Fe) by electrospinning. They are shown to be a viable sorbent for pipette-tip solid-phase extraction for the extraction of the benzodiazepine drugs nitrazepam and oxazepam. The nanofibers were characterized by scanning electron microscopy, energy dispersive X-ray spectroscopy, Fourier transform infrared spectroscopy and X-ray diffraction. The effects of sample pH value and volume, composition, and amount of electrospun nanofibers, the number of adsorption cycles and the type and volume of the eluent were optimized. Following extraction the drugs were quantified by HPLC. Under the optimized conditions, response is linear for both drugs in the 5.0-1000 ng mL-1 concentration range. The limits of detection for oxazepam and nitrazepam are 1.5 and 2.5 ng mL-1, respectively, and the relative standard deviations at the levels of 50, 100 and 250 ng mL-1 (for n = 3) are ≤7.6%. The method was successfully applied for determination of drugs in spiked wastewater and biological fluids. Graphical abstractSchematic representation of polyacrylonitrile/MIL-53(Fe) composite nanofiber synthesis by electrospinning, and the use of them as the sorbent in pipette-tip microsolid-phase extraction (PT-µSPE) for the preconcentration of Nitrazepam and Oxazepam before HPLC-DAD analysis.