Eluent Volume Research Articles

Enhanced Pb(II) extraction using a novel chitosan/pectin/carbon composite adsorbent for solid-phase extraction

ABSTRACT This research aimed to present the development of chitosan/pectin/carbon (CPC) materials as adsorbents in the solid-phase extraction (SPE) of Pb(II) from river water samples. The CPC adsorbent shows active groups effectively binding Pb(II) ions. The characterisation included using Fourier Transform Infrared Spectroscopy (FTIR) and Scanning Electron Microscopy with Energy-Dispersive X-ray Spectroscopy (SEM-EDX) to analyse functional groups and evaluate surface morphology with elemental composition. SPE parameters were systematically optimised to enhance adsorption-desorption efficiency, including pH 4.0, Pb(II) concentration of 5 mg L−1, flow rate of 13.3 mL min−1, elution flow rate of 12.8 mL/min using nitric acid (HNO3), a sample volume of 25 mL, eluent volume of 1 mL and concentration at 1.0 M. The results showed that the implementation of the refined CPC-based SPE method for Pb(II) analysis in water samples obtained a recovery range of 101% to 103%, accompanied by a significant 25-fold concentration enrichment of Pb(II). Moreover, the adsorption concentration increased from undetectable levels to 1.27–2.48 mg L−1, reporting the efficacy of the CPC-based SPE method for sensitive and accurate Pb(II) analysis in environmental samples.

Application of deep eutectic solvent based dispersive liquid–liquid microextraction method followed by HPLC-DAD for quantification of selected neonicotinoid pesticides in vegetable oils

The use of deep eutectic solvents (DES) as alternative green solvents in various analytical chemistry fields has garnered attention of researchers globally. Therefore, this study presents environmentally friendly DES for extraction of selected neonicotinoids (acetamiprid, imidacloprid, thiacloprid and thiamethoxam) prior to their determination using high-performance liquid chromatography- diode array detector (HPLC-DAD). The DES mixture that resulted in the highest extraction recoveries of neonicotinoids (NEOs) was choline chloride with ethylene glycol (CCl:EG) and nuclear magnetic resonance and Fourier transform infrared confirmed the successful synthesized CCl:EG. Thereafter, the CCl:EG was applied in dispersive liquid–liquid microextraction (DLLME) for the preconcentration and extraction of acetamiprid, imidacloprid, thiacloprid and thiamethoxam. The optimum factors affecting extraction efficiency of the DES-DLLME procedure were 0.8 mL (DES volume), 4.5 min (extraction time), 0.5 mL (eluent volume), 7 pH and 75 s (eluent time). The optimized DES-DLLME achieved limit of detection (LOD) and quantification (LOD) range of 0.4–4.95 ng.µL−1 and 1.43–9.70 ng.µL−1 respectively. Additionally, the extraction method achieved good accuracy (79.0–119.6 %), preconcentration factors (39.3–118), interday (0.61–1.62 %) and intraday (0.1–0.98 %) precisions. The greenness assessment of the proposed DES-DLLME method using AGREE, NEMI and AES tools revealed that the method was green. Finally, the developed DES-DLLME method was applied to real vegetable oils and the concentrations were below detection limits.

Polypyrrole as Adsorbent in Magnetic Solid Phase Extraction for Progesterone Determination from Human Plasma.

A straightforward and effective chromatographic method has been created for the analysis of progesterone from human plasma using a composite based on polypyrrole/magnetic nanoparticles in the sample preparation procedure. The quantification of progesterone is necessary due to its importance in human development and fertility. The employed conditions used acetonitrile:ultrapure water (70:30, v/v) as the mobile phase at 1.0 mL min-1 and an octadecyl silane column (Phenomenex Gemini, 250 mm × 4.6 mm, 5 μm) at a wavelength of 235 nm. The composite and its precursors were synthesized and properly characterized by X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy/energy dispersive spectroscopy, thermogravimetric analysis, and point of zero charge. The main factors affecting the extraction recovery of progesterone from pool human plasma samples employing magnetic solid phase extraction have been studied, such as sample pH (without adjustment), sample volume (1000 μL), washing solvent (ultrapure water), eluent (acetonitrile), eluent volume (1000 μL), and amount of adsorbent (10 mg). The extraction recoveries ranged from 98% to 102%, and linearity ranged from 5 to 3000 ng mL-1. The correlation coefficient (r) was ≥0.99, and acceptable relative standard deviation (precision), relative error (accuracy), and p-values (robustness) were observed. Lastly, the plasma samples from pregnant women were successfully analyzed by the validated method.

Synthesis of magnetic multi-walled carbon nanotubes with layered double hydroxide (M-MWCNTs@MnAl-LDH) nanocomposite as an adsorbent for lead extraction

MnAl layered double hydroxide hybrid with magnetic-multiwalled carbon nanotubes was synthesized by a hydrothermal method and used for the extraction of Pb(II) (lead) from spices and water samples in the dispersive solid phase microextraction (dSPμE) technique using FAAS. The as-prepared adsorbent MMWCNTs@MnAl-LDH was characterized by XRD, FTIR, EDX, and SEM techniques. Various analytical parameters were optimized, including pH 8, adsorbent dosage of 5 mg, HNO3 eluent concentration of 1 mol L−1, eluent volume of 3 mL, eluent time of 60 s, and sample volume of 20 mL, for quantitative lead recoveries, with an LOD of 0.314 μg L−1, an LOQ of 1.048 μg L−1, and PF of 11.53. Under the optimized conditions, the linearity ranges from 0.5 to 500 μg L−1 (R2 = 0.9997). For the validation test of the established dSPμE procedure, Certified reference materials (CRMs) were used, yielding satisfactory recovery results ranging from 97.8 to 102.7 %. The method was applied to determine lead in turmeric, tap water, and industrial water samples.

Interaction between modified magnetic nanoparticles and human albumin: Kinetics and isotherm studies and application in protein depletion

Magnetic nanoparticles modified with tetraethyl orthosilicate (Fe3O4@TEOS) and bovine serum albumin (Fe3O4@TEOS@BSA) were evaluated as sorbent in albumin depletion from human serum samples by magnetic dispersive solid phase extraction. Characterization studies were carried out by X-ray diffraction, thermogravimetry, Fourier transform infrared spectroscopy, zeta potential, and scanning electron microscopy. Both nanoparticles also showed high thermal stability and pH-dependent surface charges. The human serum albumin adsorption protocol was optimized using a central composite rotatable design. Nanoparticle mass, pH, and albumin concentration were the most influential variables. Avrami's fractional order and Freundlich isotherm models best fitted the data for human albumin adsorption kinetic and isotherm studies for Fe3O4@TEOS and Fe3O4@TEOS@BSA, and the maximum adsorption capacities were 11.93 and 14.89 mg g−1, respectively. The protein desorption was influenced by the pH of samples and eluent volume. Electrophoresis in a polyacrylamide gel containing sodium dodecyl sulfate showed different patterns of serum protein bands when consecutive depletions were performed. The Fe3O4@TEOS showed greater affinity for HSA and efficiency in depletion. The process was versatile, and the depleted albumin proportion could be controlled by the nanoparticle masses. The proposed method is a powerful sample preparation technique for rapid, reliable, and specific depletion of albumin.

A capsule phase microextraction protocol combined with GC–MS/MS for the determination of polychlorinated biphenyls in water samples

Due to the adverse effects of polychlorinated biphenyls (PCBs) on human health and ecosystems, their careful monitoring is necessary. In this work, capsule phase microextraction (CPME) combined with gas chromatography-tandem mass spectrometry (GC–MS/MS) was used to extract and determine eight PCBs in water samples. As an extraction device for the CPME procedure, two permeable microporous polypropylene tubes were employed. They contained sol–gel carbowax 20 M (sol–gel CW 20 M) sorbent and a cylindrical magnet. The adsorption and desorption conditions (i.e., type of capsule, sample volume, extraction time, stirring rate, ionic strength, type and volume of eluent, and desorption time) of the microextraction procedure were studied. Under optimum conditions, the extraction was achieved within 20 min using 20 mL of sample at a stirring rate of 1000 rpm, while the elution was performed by immersing the CPME device in 500 μL of acetone for 5 min. Accordingly, the analytical method was validated in terms of linearity, sensitivity, selectivity, enhancement factor, accuracy, and precision, and its greenness and applicability were evaluated. The obtained limits of quantification were equal to 0.010–0.050 μg L−1. The relative recoveries were equal to 91.4 and 110.6 % for intra-day and 88.0–111.2 % for inter-day study, while the relative standard deviation values were better than 10.9 %. Finally, the developed method was used for the analysis of real water samples, proving good fitness-for-purpose.

Magnetic solid phase extraction of methiocarb pesticide from food samples prior to HPLC analysis with magnetic activated carbon cloth/zinc aluminate (magnetic ACC@ZnAl2O4) composite

Methiocarb is a carbamate pesticide and is widely used due to its short lifetime but is a health concern due to its toxicity. To address this challenge, a novel nano-sorbent (zinc aluminate hybrid doped onto a magnetic activated carbon cloth (magnetic ACC@ZnAl2O4)) was synthesized. The characterization of the composite was done using FTIR spectroscopy, SEM, XRD, and EDX. The synthesized composite was then employed for the efficient extraction of methiocarb from food samples. Under the optimum conditions of (pH: 7.0, vortex time: 0.5 min, adsorbent dose: 5 mg, initial volume of sample: 50 mL, volume of eluent: 1.0 mL), quantitative recovery values of methiocarb in food samples were obtained (80–114%). This method impresses with its exceptional sensitivity, achieving incredibly low detection (LOD: 20 µg L−1) and quantification (LOQ: 67 µg L−1) limits for methiocarb. Its efficiency is equally impressive, with high values of preconcentration factor (PF: 50) and enhancement factor (EF: 49.4), ensuring accurate and reliable analysis with a low value of relative standard deviation (RSD: 4.8%). The method’s impressive selectivity, evident in its minimal interference from other pesticides, paves the way for reliable methiocarb analysis in food samples.

Silver Core Coated with Molecularly Imprinted Polymer as Adsorbent in Pipet-Tip Solid Phase Extraction for Neonicotinoids Determination from Coconut Water.

In this work, we report an innovative adsorbent named Ag-MPS@MIP that has a core@shell structure, i.e., silver nanoparticles modified with 3-methacryloxypropyltrimethoxysilane as the core and molecularly imprinted polymer based on methacrylic acid as its shell. Thiamethoxam, imidacloprid, and acetamiprid were extracted from coconut water samples using Ag-MPS@MIP in pipet-tip solid phase, prior to high-performance liquid chromatography analysis. The separation was carried out on isocratic mode using a mobile phase consisting of C18 column (Phenomenex, 150 mm × 4.6 mm, 5 μm), ultrapure water acidified with 0.3% phosphoric acid:acetonitrile (78:22, v/v), flow rate at 1.0 mL min-1, injection volume of 10 μL, temperature of 25 °C, and wavelength at 260 nm. The adsorbent and precursor materials were properly characterized by different instrumental techniques. The main factors affecting the recovery of analytes from coconut water samples by pipet-tip solid phase were optimized, such as sample volume (250 μL), sample pH (pH = 5.0), ionic strength (1%, m/v), washing solvent (300 μL ultrapure water), volume and type of eluent (500 μL methanol), amount of adsorbent (15 mg), cycle of percolation-dispensing (1×), and reuse (5×). Thereby, the neonicotinoids presented extraction recoveries between 82.80 and 96.36%, enrichment factor of 5, linearity ranged from 15 to 4000 ng mL-1, correlation coefficient (r) > 0.99, limit of detection of 5 ng mL-1, satisfactory selectivity, stability, and proper precision (RSD%: 0.52-9.64%) and accuracy (RE%: -5.19-6.45%). The method was successfully applied to real samples of coconut water.

Development of dispersive solid phase extraction method for the preconcentration of parathion ethyl as a simulant of nerve agent sarin from soil, plant and water samples prior to GC-MS determination.

In the presented study, an efficient and fast analytical method was developed for the determination of parathion ethyl as sarin simulant by gas chromatography-mass spectrometry (GC-MS). Dispersive solid phase extraction (DSPE) was performed to concentrate parathion ethyl from soil, plant and water samples. Reduced graphene oxide-iron (II, III) oxide (rGO-Fe3O4) nanocomposite was used as an adsorbent to collect the target analyte from the aqueous sample solutions. After the optimization of extraction/preconcentration parameters, optimum conditions for adsorbent amount, eluent type, mixing type/period, eluent volume and initial sample volume were determined as 15mg, acetonitrile, vortex/30s, 100 µL and 10mL, respectively. Under the optimum conditions, analytical performance of the developed DSPE-GC-MS method was evaluated in terms of limit of detection (LOD), limit of quantitation (LOQ) and dynamic range. Dynamic range, LOD and LOQ values were figured out to be 0.94-235.15µg/kg, 0.41µg/kg and 1.36µg/kg (mass based), respectively. Satisfactory percent recovery results (90.3-125% for soil, 93.5-108.7% for plant, 88.5-112.9% for tap water) were achieved for soil, plant and tap water samples which proved the accuracy and applicability of the developed method. It is predicted that the DSPE-GC-MS method can be accurately used for the detection of sarin in soil, plant and water samples taken from war territories.

Magnetic solid-phase extraction technique based on Fe3O4@coPPy-PTH nanocomposite for extraction of cobalt, chromium, and nickel prior to determination by microsample injection system-flame atomic absorption spectrometry in alcoholic and nonalcoholic beverages.

A novel Fe3O4@coPPy-PTH nanocomposite-based sorbent was prepared via in situ oxidative polymerization using Fe3O4 nanoparticles with spherical and flower-like morphologies of thiophene and pyrrole as the feedstocks. The synthesized nanocomposite displayed sensitive extraction and determination of metal ions Co(II), Cr(III), and Ni(II) without a chelating agent, followed by microsample injection system-flame atomic absorption spectrometry. Advanced spectroscopic and imaging techniques including scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy were used to characterize the composition and morphology of the Fe3O4@coPPy-PTH nanocomposite. SEM observations showed that the size of the Fe3O4 nanoparticles changed from 30 nm to 120 nm in diameter after copolymer (PPy-PTH) coating. The Fe3O4@coPPy-PTH nanocomposite has good dispersion properties and stability in strong acid solutions. For effective extraction of the studied analytes, the influence of sample pH, volume of sample solution and eluent, amount of adsorbent, and interference of coexisting metal ions were optimized. Under the optimum conditions, preconcentration factors were obtained as 25 for all analytes. The calibration curves were linear in the range of 0.0-10.0 μg L-1 with coefficients of determination (R2) greater than 0.9957 for all three analytes. Limits of detection (S/N = 3) were calculated in the range of 0.17-0.23 μg L-1. Precision values, expressed as relative standard deviations, were lower than 3.0%, and relative recoveries were obtained in the range of 88.6%-103.6%. The proposed method (Fe3O4@coPPy-PTH/MSPE/MIS-FAAS) was successfully applied to extract and determine the studied metal ions in beer, wine, and nonalcoholic beverage samples.

Ultrasound-assisted matrix solid-phase extraction based on deep eutectic solvents and zinc oxide: Extraction and determination of six active ingredients in Ligustri Lucidi Fructus.

In this study, we propose a novel strategy utilizing deep eutectic solvents (DESs) as both the extraction solvent and dispersing liquid, with nanometer zinc oxide (ZnO) serving as the adsorbent. This method incorporates ultrasound-assisted matrix solid phase dispersion (UA-MSPD) for the extraction of six active components (salidroside, echinacoside, acteoside, specnuezhenide, nuezhenoside G13, and oleanolic acid) from Ligustri Lucidi Fructus samples. The extracts were then analyzed using high-performance liquid chromatography equipped with a diode array detector. The effects of various parameters such as dispersant dosage, DESs volume, grinding time, ultrasonication duration, and eluent volume on extraction recovery were investigated and optimized using a central composite design under response surface methodology. The optimized conditions yielded detection limits ranging from 0.003 to 0.01mg/g and relative standard deviations of 8.7% or lower. Extraction recoveries varied between 93% and 98%. The method demonstrated excellent linearity for the analytes (R2 ≥ 0.9997). The simple, green, and efficient DESs/ZnO-UA-MSPD technique proved to be rapid, accurate, and reliable for extracting and analyzing the six active ingredients in Ligustri Lucidi Fructus samples.

Flow analysis-solid phase extraction system and UHPLC-MS/MS analytical methodology for the determination of antiviral drugs in surface water

An automated flow analysis-solid phase extraction (FA-SPE) system and methodology of ultra-high-performance liquid chromatography with tandem mass spectrometry (UHPLC-MS/MS) analysis were developed for the determination of selected antiviral drugs (acyclovir, amantadine, rimantadine, and oseltamivir) in water samples. The proposed FA-SPE approach enables the integration of various extraction stages and elimination of the sample evaporation step and offers individual customisation of SPE parameters, inter alia sample, and eluate flow rate and volume. Using the developed FA-SPE procedure, e.g. a 100-fold preconcentration of the target analytes in 1 h was achieved. A method for chromatographic analysis was also developed to determine the selected antiviral drugs in combination with the use of the FA-SPE system. The developed FA-SPE UHPLC-MS/MS method was validated including the determination of linearity of analytical graphs, limits of detection (5.5–99.9 pg mL−1) and quantification (18.3–329.8 pg mL−1), intra-day (1.8–8.3%) and inter-day (3.0–9.2%) precision, recovery (95.6–105.3%), and matrix effects (− 12.9 to 13.2%). The proposed method was successfully applied to analyse tap, drinking, and river water samples, revealing the presence of amantadine at a concentration of 40.1 pg mL−1 in one sample. The environmental impact of the developed FA-SPE sample preparation procedure was also assessed using the AGREEprep metric tool and compared with five other literature methods, achieving the most sustainable outcome.Graphical abstract

Dispersive-solid phase extraction of diniconazole from water and fruit juice samples using MnCoCu-LDHs@MOF-235 nanocomposite

In this study, a new, affordable, and promising adsorbent based on MnCoCu-LDHs@MOF-235(Fe) nanocomposite was successfully synthesized, characterized, and utilized for the solid phase extraction of diniconazole (DNC) pesticide from water and food samples before it was determined by liquid chromatography. The structural characteristics of the synthesized nanocomposite were confirmed by various techniques, including FTIR, XRD, FE-SEM, and FE-SEM-EDX. The central composite design (CCD) technique was used for multi-response optimization of effective parameters including the sample solution’s pH (6.0), adsorbent amount (15 mg), adsorption time (5 min), sample volume (30 mL) and eluent volume (2.5 mL), and desorption time (3 min) to achieve optimum extraction efficiency. Under optimal conditions, the method’s analytical performance was assessed. The results showed that the calibration graphs showed linearity for DNC in the range of 1.3–500 µg L−1, with a detection limit of 0.4 µg L−1 and a correlation coefficient of 0.9988. Additionally, 2.9 intra-day RSD, 6.1 inter-day RSD, 12.0 preconcentration factor, and 2.53–11.53 enrichment factors was attained. The performance of the method to extract DNC from nine different real samples was realized with high relative recoveries (88.0–108 %). In addition, the greenness of the method was assessed with the AGREE metric tool, confirming that the method is environmentally friendly.

Pb(II) solid-phase extraction in wastewater samples prior to flame atomic absorption spectrometry analysis using chitosan and alginate modified carbon

ABSTRACT The sustainability concept was kept in view by designing and synthesising a novel adsorbent for Pb(II) ion, using natural and metal-free precursors which are renewable and biodegradable, i.e. alginate, chitosan, and carbon. The study was aimed to introduce the synthesis of Carbon/Alginate/Chitosan composite (CAC) as a beneficial adsorbent tailored for the solid-phase extraction (SPE) of Pb(II) prior to its analysis via flame atomic absorption spectrometry (FAAS). The successful preparation of the CAC material is elucidated, characterised through FTIR for functional group analysis, and evaluated for surface morphology and elemental composition via SEM-EDX. Optimisation of SPE parameters was carefully conducted to enhance adsorption-desorption efficiency across diverse conditions. These optimised factors were a pH level of 6, initial Pb(II) concentration of 20 mg/L, sample flow rate 5 mL/min, elution utilising Na2EDTA at a rate of 5 mL/min, sample volume of 20 mL, Na2EDTA eluent volume of 10 mL, and Na eluent concentration of 0.5 M. Application of CAC-based SPE for Pb(II) analysis in wastewater samples under these optimised conditions yielded exceptional recovery rates of 93–96%, with a limit of detection (LoD) value of 71.4 µg/L. Moreover, a notable preconcentration factor of 4–8 times is achieved for Pb(II) in wastewater samples, facilitating the detection of Pb(II) concentrations as low as 30 µg/L.

Nickel−manganese−cobalt tetragonal spinel ternary oxide nanocomposite as an effective adsorbent for dispersive solid phase micro-extraction of cadmium in food and water samples

Nickel−manganese−cobalt tetragonal spinel ternary oxide nanocomposite (NMC-TSO) was synthesized. It was utilized as an efficient sorbent for the dispersive solid phase microextraction (D-SPμE) without vortexing of cadmium. The analysis of the cadmium was carried out by FAAS. The effective analytical parameters including pH (6) contact times (no vortexing), sample volume (70 mL), eluent volume (3 mL of 2 mol L−1 HCl), linear dynamic ranges (1.07–85.7 μg L−1), and re-useability (33) on the D-SPμE efficiency were investigated. The PF, RSD% and LOD of the D-SPμE for cadmium were 23.3, ≤ 2.8% and 0.49 μg L−1, respectively. The tolerable concentrations of Ca2+, Mg2+, K+ and Na+ on Cd(II) were 50,000 mg L−1, 50,000 mg L−1, 25,000 mg L−1 and 7500 mg L−1, respectively. The method was accurated by analysis of food and water certificate reference materials (NW-TMDA-54.6 Lake water, SPS-WW1 121 Batch wastewater, 1573a Tomato Leaves and TORT-3 Lobster Hepatopancreas) and - recovery experiments. The D-SPμE-FAAS method was applied for the cadmium determination in dam water, wastewater, river water, well water, sea water, tea, cacao, nut, bitter chocolate, rice, leek, cinnamon and parsley.

A facile in-situ ultrasonic-assisted synthesis of terephthalic acid-layered double hydroxide/bacterial cellulose: Application for eco-friendly analysis of multi-residue pesticides in vineyard soils

A novel nanostructure biosorbent comprised of bacterial cellulose (BC) and a Cu-Cr layered double hydroxide (LDH) intercalated with terephthalic acid (TPA) was prepared using the in-situ coprecipitation method. The synthesized TPA/CuCr-LDH@BC sorbent was used in quick, easy, cheap, effective, rugged, and safe (QuEChERS) extraction of multiclass pesticides (nine insecticides, five acaricides, one herbicide, and one fungicide) followed by gas chromatography-mass spectrometry. The extraction factors such as type and volume of eluent, sorbent dosage, adsorption and desorption times, sample pH, and salt were optimized. The sorbent was analyzed with field emission scanning electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy, and adsorption/desorption isotherms to check its chemical structure, crystallinity, and porosity. Matrix effect (15.3–19.6 %), linearity (20–2000 µg/L, r2 > 0.9982), limits of quantification (6–12 µg/L), and enrichment factor (42–65) were calculated. The efficiency and accuracy of the developed method were assessed with the analysis of five vineyard soil samples and the resulting recoveries were in the range of 60–130 % (RSD%=3.5–12.9). The green aspects of the procedure were evaluated by the Complex-GAPI, the AGREE, and the Analytical Eco-Scale tools. This study describes the first-time synthesis of TPA/CuCr-LDH@BC composite and its application as sorbent material for the microextraction of multi-residue pesticides in agricultural soils.

Quantitative analysis of organosulphur compounds in crude oil samples using magnetic solid phase extraction based on Au-Fe3O4 adsorbent and gas chromatography with time-of-flight mass spectrometry

This study focused on the development of a magnetic solid phase extraction (m-SPE) method using Au-Fe3O4 as an adsorbent followed by GC-ToFMS analysis for the determination of organosulphur compounds (OSCs) in fuel samples. The m-SPE using Au-Fe3O4 NPs was preferred because of the low toxicity of the adsorbent1, high separation efficiency using external magnet2 and greater extraction selectivity between sulphur and Au atom3. The Au-Fe3O4 NPs were characterized using XRD, UV–Vis, TEM, SEM and FTIR. This method was optimized using multivariate analysis based on a two-level full factorial and central composite designs. The conditions which produced optimum efficiency were found to be 150 mg mass of sorbent, 100 µL eluent volume, 50 min extraction time and 6,5 pH of the sample. These optimum conditions showed a relatively low limit of detection in the range of 0.02–0.199nµg/g and limit of quantification of 0.08–0.602 µg/g. Furthermore, a relative standard deviation of triplicates analysis was between 0.8 and 2.3% with good linearity of 0.9816–0.9961. The percentage recovery for thiophene, 3-methylthiophene, benzothiophene and dibenzothiophene ranged from 76 to 95% for the spiked samples. The optimized m-SPE method was then applied in real fuel oil samples. The concentration of thiophene, 3-methylthiophene, benzothiophene and dibenzothiophene in crude oil, gasoline, diesel and kerosene ranged from 0.43–1.94 µg/g, 0.78–1.63 µg/g, 0.95–4.31 µg/g to 1.55–2.09 µg/g, respectively. The m-SPE, followed by GC-ToFMS method, proved to be efficient, inexpensive and an alternative method for OSCs analysis in fuel oils.

Biochar-based polymeric film as sustainable and efficient sorptive phase for preconcentration of steroid hormones in environmental waters and wastewaters

BackgroundThe environmental impact of sample preparation should be minimized through simplification of the procedures and the use of natural, renewable and/or reusable materials. In such scenario, thin-film microextraction fulfils the former criteria, as it enables few steps and miniaturization, thus small amount of extraction phase. At the same time, the use of sorbents such as biochars obtained from biomass waste is even more promoted due to their availability at low cost and increased life-cycle in a circular economy vision. However, it is not always easy to combine these criteria in sample preparation. ResultsA thin film microextraction was developed for the determination of steroids in aqueous samples, entailing a membrane made of cellulose triacetate and a wood-derived biochar (Nuchar®) as carbon precursor. Different characterization techniques showed the successful preparation, whereas the sorption kinetics experiments demonstrated that biochar is responsible for the extraction with the polymer acting as a smart support. After a study about membranes’ composition in terms of biochar amounts (4 %, 10 %, 16 % wt) and type of synthesis set up, the ceramic 3D-mold was selected, achieving reproducible and ready-to-use membranes with composition fixed as 10 %. Different elution conditions, viz. type and time of agitation, type, composition and volume of eluent, were evaluated. The final microextraction followed by HPLC-MS/MS quantification was successfully validated in river and wastewater treatment plant effluent samples in terms of accuracy (R% 64–123 %, RSD<19 % in river; R% 61–118 %, RSD <18 % in effluent, n = 4), sensitivity (MQLs 0.2–8.5 ng L−1) and robustness. SignificanceThis novel biochar-based polymeric film proved to be a valid and sustainable sorbent, in terms of extraction capability, ease of preparation and greenness. By comparison with literature and the greenness evaluation with the most recent metric tools, this method expands the potential applicability of the thin-film microextraction and opens up innovative scenarios for sustainable procedures entailing the use of biochars entrapped in bio-polymers.

Dispersive micro-solid phase extraction coupled with spectrophotometric using (MgFe CLDH)/GO magnetically separable sorbent for pre-concentration of anionic food dyes in water samples

In the present study, a method was described for the extraction of Sunset Yellow (SY) and Tartrazine (TZ) as anionic food dyes in actual samples by using magnetic calcined layered double hydroxide onto graphene oxide (MgFe CLDH)/GO (called MgO/MgFe2O4/GO) sorbent. The analytes were accumulated on MgO/MgFe2O4/GO-NCs with more detail recognized by XRD, FESEM, EDS element mapping, VSM and FTIR methods. The prepared nanocomposite (NC) was employed as an extractive phase for dispersive micro-solid phase extraction (D-μ-SPE) of SY and TA from actual samples. Then, the extracted SY and TZ dyes were analyzed by UV–vis spectrophotometer. Main variables related to the extraction process including pH, nano composite mass, sonication and vortex time and eluent volume were optimized by central composite design (CCD). The optimum conditions obtained for pH, nano composite mass, sonication and vortex time and eluent volume were 6.0, 0.02 g, 16 s and 6.40 min, and 500 μL, respectively. The extraction recovery equal to 96.31 % and 97.66 % for SY and TZ, respectively obtained from the predicted model, was in agreement with the experimental data (95.32 ± 2.33 % and 96.89 ± 1.84 %). In addition, under the optimal conditions, the calibration curve was found out to be linear over the concentration range of 0.5–2.50 mg L−1 with R2 > 0.98. The LODs ranged from 0.14 to 0.16 mgL−1. Furthermore, the enrichment factors (EF) were achieved in the range of 20.65–36.66 with pre-concentration factor (PF) of 20. In the meantime, the obtained assay accuracy in the analysis of medical extract of Miranda Drink, Saffron and water samples fell within the range of 93.00%–107.00 %, whilst the precision expressed RSD lower than 3.50 %.

Characterization of vitamin D3 biotransformation by the cell lysate of Actinomyces hyovaginalis CCASU-A11-2

A former work conducted in our Lab, lead to in a effective scale up of vitamin D3 bioconversion into calcitriol by Actinomyces (A.) hyovaginalis isolate CCASU-A11-2 in Lab fermenter (14 L) resulting in 32.8 µg/100 mL of calcitriol. However, the time needed for such a bioconversion process was up to 5 days. Therefore, the objective of this study was to shorten the bioconversion time by using cell-free lysate and studying different factors influencing bioconversion. The crude cell lysate was prepared, freeze-dried, and primarily fractionated into nine fractions, of which, only three fractions, 50, 100, and 150 mM NaCl elution buffers showed 22, 12, and 2 µg/10 mL, calcitriol production, respectively. Ammonium sulfate was used for protein precipitation, and it did not affect the bioconversion process except at a concentration of 10%w/v. Secondary fractionation was carried out using 80 mL of the 50 mM NaCl elution buffer and the results showed the 80 mL eluent volume was enough for the complete elution of the active protein. The pH 7.8, temperature 28 °C, and 6 h reaction time were optimum for maximum calcitriol production (31 µg/10 mL). In conclusion, the transformation of vitamin D3 into calcitriol was successfully carried out within 6 h and at pH 7.8 and 28 °C using fractionated cell lysate. This process resulted in a 10-fold increase in calcitriol as compared to that produced in our previous study using a 14 L fermenter (32.8 µg/100 mL). Therefore, cell-free lysate should be considered for industrial and scaling up vitamin D3 bioconversion into calcitriol.