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.

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.

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.

A nanosized magnetic metal-organic framework of type MIL-53(Fe) as an efficient sorbent for coextraction of phenols and anilines prior to their quantitation by HPLC.

The authors describe the synthesis of a magnetic metal-organic framework (MOF) of type MIL-53(Fe) for coextraction of phenols and anilines from various environmental samples. A quick method for dispersive micro-solid phase extraction (D-µ-SPE) was developed for coextraction of the analytes 4-nitrophenol (4-NP), 4-chlorophenol (4-CP), 4-chloroaniline (4-CA), 1-amino-2-naphtol (1-A2N) and 2, 4-dichloroaniline (2, 4-DCA). The MOF was characterized by SEM, TEM, FT-IR, EDS, thermogravimetry, VSM and XRD. The method was optimized by response surface methodology combined with desirability function approach, specifically with respect to pH value of the sample, amount of sorbent, sorption time, salt concentration, sample volume, type and volume of the eluent, and elution time. Following elution with acetonitrile, the analytes were quantified by HPLC with photodiode array detection. Responses are linear in 0.1-2000 µg·L-1 concentration ranges. The limits of detection and relative standard deviations (for n = 5) are in the range of 0.03-0.2 µg·L-1 and 3.5-12.6%, respectively. Enrichment factors are 113, 61, 87, 144 and 114 for 4-NP, 4-CP, 4-CA, 1-A2N and 2,4-DCA, respectively. Recoveries from spiked samples ranged from 39.5 to 93.3%. The magnetic sorbent was successfully applied to the coextraction and determination of the analytes in river, rain and hookah water samples. Graphical abstract Schematic presentation for the synthesis of (a) Fe3O4 nanoparticles (NPs) and (b) Fe3O4@MIL-53(Fe). Fe3O4@MIL-53(Fe) was employed as a new nanosorbent in dispersive micro-solid phase extraction of phenols and anilines. The limits of detection are in the range of 0.03-0.2 µg·L-1.

Synthesis and characterization of a poly(p-phenylenediamine)-based electrospun nanofiber for the micro-solid-phase extraction of organophosphorus pesticides from drinking water and lemon and orange juice samples.

A new micro-solid-phase extraction sorbent was synthesized by electrospinning poly(p-phenylenediamine)/poly(vinyl alcohol) in the presence of cetyltrimethylammonium bromide. The modified nanofiber was prepared by removing the majority of the poly(vinyl alcohol) from the nanofiber blend by exposing it to the hot water. Scanning electron microscopy and surface analysis were performed to study the homogeneity and porosity of the electrospun nanofiber. In addition, Fourier transform infrared spectroscopy was applied for more characterization. The capability of the new nanofiber was explored by applying it in the extraction and preconcentration of organophosphorus pesticides from aqueous medium. After solvent desorption, the extracted analytes were analyzed by high-performance liquid chromatography with diode array detection. Under the optimum conditions, the relative standard deviation values at the concentration level of 50 ng/mL were in the range of 4.8-8.3%. The calibration curve showed linearity in the range of 0.5-500 ng/mL, and the limits of detection (S/N = 3) for the studied compounds were 0.15 ng/mL. By analyzing Tehran drinking water, lemon juice, sour lemon juice, orange juice and sour orange juice, the applicability of the presented method was investigated and the relative recoveries were in the range of 76-102%.

Dispersive magnetic solid-phase extraction of phthalate esters from water samples and human plasma based on a nanosorbent composed of MIL-101(Cr) metal-organic framework and magnetite nanoparticles before their determination by GC-MS.

In this study, a magnetic metal-organic framework was synthesized simply and utilized in the dispersive magnetic solid-phase extraction of five phthalate esters followed by their determination by gas chromatography with mass spectrometry. First, MIL-101(Cr) was prepared hydrothermally in water medium without using highly corrosive hydrofluoric acid, utilizing an autoclave oven heat supply. Afterward, Fe3 O4 nanoparticles were decorated into the matrix of MIL-101(Cr) to fabricate magnetic MIL-101 nanocomposite. The nanocomposite was characterized by various techniques. The parameters affecting dispersive magnetic solid-phase extraction efficiency were optimized and obtained as: a sorbent amount of 15 mg; a sorption time of 20 min; an elution time of 5 min; NaCl concentration, 10% w/v; type and volume of the eluent 1 mL n-hexane/acetone (1:1 v/v). Under the optimum conditions detection limits and linear dynamic ranges were achieved in the range of 0.08-0.15 and 0.5-200 µg/L, respectively. The intra- and interday RSD% values were obtained in the range of 2.5-9.5 and 4.6-10.4, respectively. Ultimately, the applicability of the method was successfully confirmed by the extraction and determination of the model analytes in water samples, and human plasma in the range of microgram per liter and satisfactory results were obtained.

Polypyrrole coated ZnO nanorods on platinum wire for solid-phase microextraction of amitraz and teflubenzuron pesticides prior to quantitation by GC-MS.

The authors describe a new sorbent for amitraz and teflubenzuron pesticides. It consists of a platinum wire coated with polypyrrole-coated ZnO nanorods. The nanocomposite was prepared by a two-step process. In the first step, oriented ZnO nanorods were hydrothermally grown in situ on a platinum wire. Subsequently, oxidative vapor phase polymerization of pyrrole was performed on FeCl3-impregnated ZnO nanorods to give a porous polypyrrole film. The organic/inorganic nanocomposite synthesized through hydrothermal deposition and chemical vapor deposition polymerization yields material with attractive properties. The coated wire was applied to solid-phase microextraction of amitraz (in the form of 2,4-dimethylaniline resulting from the hydrolysis of amitraz) and teflubenzuron. The effects of extraction temperature, extraction time, sample pH value and salt concentration were optimized. The analytes 2,4-dimethylaniline and teflubenzuron were then quantified by GC-MS. Under optimum conditions, the LODs range between 0.1 and 0.15 ng.mL-1. Relative standard deviations at two concentration are <8.3% for intraday precision and <10.3% for inter-day precision. In all cases, the fiber to fiber reproducibility is <12.2%. For both analytes the linear dynamic ranges are 0.5-300 ng.mL-1. The procedure was successfully applied to the analysis of spiked agricultural water samples. Graphical abstract A novel inorganic/organic hybrid nanocomposite was synthesized through in situ hydrothermal deposition of ZnO nanorods and ten placing a thin layer of polypyrrole on them by chemical vapor deposition polymerization. This nanocomposite was applied to fabricate a solid-phase microextraction fiber for the extraction of amitraz and teflubenzuron pesticides residue from agricultural samples prior to their quantitation by GC-MS.

A poly(4-nitroaniline)/poly(vinyl alcohol) electrospun nanofiber as an efficient nanosorbent for solid phase microextraction of diazinon and chlorpyrifos from water and juice samples.

4-Nitroaniline was electropolymerized in a weakly alkaline medium, and the resulting poly(4-nitroaniline) (P4-NA)) was used to fabricate - by electrospinning - a nanofiber consisting of P4-NA and poly(vinyl alcohol) (PVA). The PVA fraction was then dissolved in hot water and this causes the porosity of electrospun nanofiber to be largely enhanced. The resulting nanofiber was utilized as a sorbent for solid phase microextraction of the model organophosphorus pesticides diazinon and chloropyrifos from aqueous media. The extracted analytes were then analyzed by corona discharge ion mobility spectrometry (CD-IMS). Under the optimized conditions, the limits of detection (at S/N = 3; for n = 10) are 0.4 and 0.6 ng mL-1 for diazinon and chloropyrifos, respectively. The relative standard deviations at the levels of 25, 50 and 100 ng mL-1 (for n = 3) ranged from 4.0-12.3% (both intra-day and inter-day). Eventually, the method was used to analyze different water samples, including spiked drinking water, sea water, lagoon water, and groundwater sample in the proximity of rice fields, and in two juice samples. Recoveries ranged between 82 and 102%. Graphical abstract An electrospun nanofiber consisting of highly porous poly(4-nitroaniline) was synthesized and used as a sorbent for solid phase microextraction of diazinon and chlorpyrifos from water and juice samples prior to quantitation by corona discharge ion mobility spectrometry.

A simple and fast method based on mixed hemimicelles coated magnetite nanoparticles for simultaneous extraction of acidic and basic pollutants.

One of the considerable and disputable areas in analytical chemistry is a single-step simultaneous extraction of acidic and basic pollutants. In this research, a simple and fast coextraction of acidic and basic pollutants (with different polarities) with the aid of magnetic dispersive micro-solid phase extraction based on mixed hemimicelles assembly was introduced for the first time. Cetyltrimethylammonium bromide (CTAB)-coated Fe3O4 nanoparticles as an efficient sorbent was successfully applied to adsorb 4-nitrophenol and 4-chlorophenol as two acidic and chlorinated aromatic amines as basic model compounds. Using a central composite design methodology combined with desirability function approach, the optimal experimental conditions were evaluated. The opted conditions were pH = 10; concentration of CTAB = 0.86 mmol L(-1); sorbent amount = 55.5 mg; sorption time = 11.0 min; no salt addition to the sample, type, and volume of the eluent = 120 µL methanol containing 5% acetic acid and 0.01 mol L(-1) HCl; and elution time = 1.0 min. Under the optimum conditions, detection limits and linear dynamic ranges were achieved in the range of 0.05-0.1 and 0.25-500 µg L(-1), respectively. The percent of extraction recoveries and relative standard deviations (n = 5) were in the range of 71.4-98.0 and 4.5-6.5, respectively. The performance of the optimized method was certified by coextraction of other acidic and basic compounds. Ultimately, the applicability of the method was successfully confirmed by the extraction and determination of the target analytes in various water samples, and satisfactory results were obtained.

Magnetic molecularly imprinted composite for the selective solid-phase extraction of p-aminosalicylic acid followed by high-performance liquid chromatography with ultraviolet detection.

A new method for the selective extraction of p-aminosalicylic acid from aqueous and urine samples has been developed using magnetic molecularly imprinted polymer nanoparticles before determination by high-performance liquid chromatography. The Fe3 O4 nanoparticles were first prepared through the chemical coprecipitation of Fe2+ and Fe3+ and then coated with a vinyl shell. Subsequently, a layer of molecularly imprinted polymers was grafted onto the vinyl-modified magnetic nanoparticles by precipitation polymerization. FTIR spectroscopy, scanning electron microscopy, vibrating sample magnetometry, and thermogravimetric analysis were applied to characterize the sorbent properties. Moreover, the predominant parameters affecting the magnetic solid phase extraction such as sample pH, sorption and elution times, the amount of sorbent, and composition and volume of eluent were investigated thoroughly. The maximum sorption capacity of the imprinted polymer toward p-aminosalicylic acid was 70.9 mg/g, which is 4.5 times higher than that of the magnetic nonimprinted polymer. The magnetic molecularly imprinted polymer nanoparticles were applied for the selective extraction of p-aminosalicylic acid from aqueous and urine samples and satisfactory results were achieved. The results illustrate that magnetic molecularly imprinted polymer nanoparticles have a great potential in the extraction of p-aminosalicylic acid from environmental and biological matrices.

Electromembrane-surrounded solid-phase microextraction coupled to ion mobility spectrometry for the determination of nonsteroidal anti-inflammatory drugs: A rapid screening method in complicated matrices.

A new robust method of electromembrane-surrounded solid-phase microextraction coupled to ion mobility mass spectrometry was applied for nonsteroidal anti-inflammatory drugs determination in complex matrices. This is the first time that a graphene/polyaniline composite coating is applied in electromembrane-surrounded solid-phase microextraction method. The homemade graphene/polyaniline composite is characterized by a high electrical conductivity and thermal stability. The variables affecting electromembrane-surrounded solid-phase microextraction, including extraction time; applied voltage and pH were optimized through chemometric methods, central composite design, and response surface methodology. Under the optimized conditions, limits of detection of 0.04 and 0.05 ng/mL were obtained for mefenamic acid and ibuprofen, respectively. The feasibility of electromembrane-surrounded solid-phase microextraction followed by ion mobility mass spectrometry was successfully confirmed by the extraction and determination of low levels of ibuprofen and mefenamic acid in human urine and plasma samples and satisfactory results were obtained.

Surfactant-assisted dispersive liquid-liquid microextraction of nitrazepam and lorazepam from plasma and urine samples followed by high-performance liquid chromatography with UV analysis.

Surfactant-assisted liquid-liquid microextraction followed by high-performance liquid chromatography with UV detection has been developed for the simultaneous preconcentration and determination of lorazepam and nitrazepam in biological fluids. In this study, an ionic surfactant (cetyltrimethyl ammonium bromide) was used as an emulsifier. The predominant parameters affecting extraction efficiency such as the type and volume of extraction solvent, the type and concentration of surfactant, sample pH, and the concentration of salt added to the sample were investigated and opted. Under the optimum conditions (extraction solvent and its volume, 1-octanol, 70 µL; surfactant and its concentration, 1 mL of ultra-pure water containing 2 mmol L-1 cetyltrimethyl ammonium bromide; sample pH = 9 and salt content of 10% NaCl w/v), the preconcentration factors were obtained in the range of 202-241 and 246-265 for nitrazepam and lorazepam, respectively. The limits of quantification for both drugs were 5 µg L-1 in water sample and 10 µg L-1 in biological fluids with R2 values higher than 0.993. The suitability of the proposed method was successfully confirmed by the extraction and determination of the target drugs in human urine and plasma samples in the range of microgram per liter.

Solid-phase microextraction of phthalate esters by a new coating based on a thermally stable polypyrrole/graphene oxide composite.

A novel polypyrole/graphene oxide coating was made by the electrochemical polymerization of pyrrole in the presence of sodium dodecyl sulfate and graphene oxide on a platinum wire. The prepared fiber has shown a good thermal stability up to 300°C. The fiber was applied to the direct solid-phase microextraction and gas chromatographic analysis of four phthalate esters. The effect of four parameters on gas chromatography peak area including extraction temperature, extraction time, injection temperature, and ionic strength were investigated. Under the optimized conditions, the detection limits were between 0.042 and 0.26 µg/L. The intraday and interday relative standard deviations obtained at 55 µg/L, using a single fiber, were 8.2-16% and 17.3-25.6%, respectively. The method was successfully applied to the analysis of phthalate esters in two real samples of boiling water in cheap disposable clear plastic drinking cups showing recoveries from 83 to 120%.

Novel modified carbon nanotubes as a selective sorbent for preconcentration and determination of trace copper ions in fruit samples.

In this work, multiwalled carbon nanotubes were reacted with N-[3-(triet-hoxysilyl)propyl]isonicotinamide to prepare pyridine-functionalized carbon nanotubes. This novel sorbent was characterized by infrared spectroscopy, thermal and elemental analysis, and scanning electron microscopy. Functionalized carbon nanotubes were applied for the preconcentration and determination of copper ions using flame atomic absorption spectrometry. Various parameters such as sample pH, flow rate, eluent type and concentration, and its volume were optimized. Under optimal experimental conditions, the limit of detection, the relative standard deviation, and the recovery of the method were 0.65 ng/mL, 3.2% and 99.4%, respectively. After validating the method using standard reference materials, the new sorbent was applied for the extraction and determination of trace copper(II) ions in fruit samples.

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%.

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.

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.

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.