Encapsulation of sesamol and retinol using alginate and chitosan-coated W/O/W multiple emulsions containing Tween 80 and Span 80.

The conditions of production of multiple W/O/W nanoemulsions containing sesamol and retinol were optimized using response surface methodology (RSM). Span 80 (5, 10, and 15 % w/v), Tween 80 (1, 5.5, and 10 % w/v), and water in oil ratio (W/O) (20, 30, and 40 %) were considered as independent variables while encapsulation efficiency (EE%) and particle size were taken as dependent variables. Alginate (Alg) and chitosan (CS) were also applied to form a deposit layer. An optimum sample with an EE of 92.93 % and particle size of 381.94 nm was produced when Tween 80, Span 80, and W/O were 6.24 %, 10.84 %, and 37.70 %, respectively. Based on the Fourier transform infrared spectroscopy (FTIR), detection of hydrophobic band (2899 cm-1) approved the physical entrapment of biomolecules. Differential scanning calorimetry (DSC) indicated an endothermic peak at 236.48 °C associated with the ionic interactions of Alg-CS. Confocal laser scanning microscopy (CLSM) indicated Alg-CS complex deposit layer formed by electrostatic attraction surrounding the W/O/W multiple layers. The in vitro release of sesamol and retinol was 39 % of sesamol and 22 % of retinol in simulated gastric fluid (SGF) and 56 % and 22 % in simulated intestinal fluid (SIF), respectively.

An efficient 3D adsorbent foam based on graphene oxide/AgO nanoparticles for rapid vortex-assisted floating solid phase extraction of bisphenol A in canned food products.

In this study, a three-dimensional adsorbent was developed based on graphene oxide/AgO nanoparticles over interconnected nickel foam (GO/AgO@Ni foam) for rapid and efficient vortex assisted floating solid phase extraction of bisphenol A in canned food products prior to high performance liquid chromatography with a fluorescence detector. The analytical techniques scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX) and Fourier transform infrared (FT-IR) were used for characterization of the synthetized GO/AgO@Ni foam. The effect of proficiency factors including pH, foam size, vortexing time, salt addition, sample volume, desorption type and volume, and desorption time on the extraction efficiency of bisphenol A were explored through the matrix match method. Under the above experimental conditions, the figures of merit of the method were acquired as LODs (S/N = 3) of 0.18-0.84 µg kg-1, LOQs of 0.61-2.81 µg kg-1 (S/N = 10), linear ranges of 0.5-500 µg kg-1, and enrichment factors of 235.5-244.9. The inter-day precision values (RSD%, n = 7) of 2.5-3.6 and the intra-day precision (%) of (5 days and seven replicates for each day) 2.8-3.8 were achieved for bisphenol A at a concentration of 50 µg kg-1. The relative recoveries of 94.0% to 99.6% were obtained for the canned food samples.

Development of a rapid efficient solid-phase microextraction: An overhead rotating flat surface sorbent based 3-D graphene oxide/ lanthanum nanoparticles @ Ni foam for separation and determination of sulfonamides in animal-based food products.

In this study, an overhead rotating flat surface sorbent based solid-phase microextraction was developed as a rapid and efficient method for simultaneous separation and determination of sulfonamides in animal based-food products. 3D graphene oxide/ lanthanum nanoparticles @ Ni foam was introduced as a novel selective sorbent. SEM-EDX and FT-IR techniques were applied for characterization of the sorbent. At optimum conditions, the linear ranges of 0.4-700.0 (µg L-1), 0.3-900.0 (µg L-1), and 0.25-500 (µg L-1) and the enrichment factors of 606.8, 604.3, 608.9 were obtained for SDZ, SMX, and SMZ, respectively. The LOD (S/N = 3) of 0.14, 0.11, 0.08 (µg L-1) were achieved for SDZ, SMX, and SMZ, respectively. The intra-day and inter-day precision (%) (five days, n = 7) for the concentration of 100 µg L-1 were less than 4.3 and 3.8, respectively. The recoveries over 90.0 % revealed high capability of the method for utilization in complex matrixes.

Chemical and Physical Characterization of the Hackberry (Celtis australis) Seed Oil: Analysis of Tocopherols, Sterols, ECN and Fatty Acid Methyl Esters.

For the very first time, the nutritional and physicochemical properties of the oil extracted from hackberry Celtis australis fruit were investigated with the aim of possible applications of such wild fruit oil. The physicochemical properties such as peroxide value, acidity, saponification, iodine value and total fat content of the extracted oil were examined extensively. The obtained results showed that peroxide value, acidity, saponification, iodine value and total fat content of the extracted oil were found to be 4.9 meq O2/kg fat, 0.9 mg KOH/g fat, 193.6 mg KOH/g fat, 141.52 mg I2/g fat and ~5%, respectively. The predominant fatty acid found in this wild fruit is linoleic acid which was calculated to be 73.38%±1.24. In addition, gamma-tocopherol (87%) and ß-sitosterol (81.2%±1.08) were the major tocopherol and sterol compositions found in Celtis australis seed oil. Moreover, equivalent carbon number (ECN) analysis has indicated that the three linoleic acids are the main composition of the triacylglycerols extracted from Celtis australis. Also, the high value of omega 6 and ß-sitosterol make this oil applicable in cosmetics and pharmaceutical applications.

Monitoring of priority pollutants chlorophenols in water and milk by headspace solid-phase microextraction based on electrospun polycaprolactam nanofibers decorated with cadmium oxide-carbon nanotubes.

Priority pollutants chlorophenols are broadly used chemicals that are persistent in the environment and causing serious human health hazards. The current study introduces a novel adsorbent for the extraction of chlorophenols from river water, surface water, and milk by headspace solid-phase microextraction coupled with gas chromatography. The adsorbent composite was prepared by blending polycaprolactam (nylon-6) mat and newly synthesized carbon nanotubes decorated with cadmium oxide nanoparticles followed by electrospinning technique to produce based nanofiber. The proposed nanofiber was characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, and X-ray diffraction techniques. The main parameters that affect extraction efficiency, including ionic strength, extraction time, desorption time, and extraction temperature, were investigated and optimized. The linear range was 0.05-5 ng/mL; the limits of detection (signal/noise=3) were 0.02-0.04 ng/mL. The relative recoveries for real samples (river water, surface water, and milk) were in the range of 84-114%.

Hyphenated dispersive solid- and liquid-phase microextraction technique based on a hydrophobic deep eutectic solvent: application for trace analysis of pesticides in fruit juices.

BACKGROUND: Pesticides are extensively used worldwide to control plant pathogens and prevent agricultural product damage. However, they can pollute the environment and endanger human health. So far, a variety of sample preparation methods have been developed for the analysis of pesticide residues. RESULTS: A hyphenated solid-liquid microextraction method based on a new adsorbent of magnetic graphene oxide functionalized by (3-glycidyloxypropyl)trimethoxysilane and a deep eutectic solvent (choline chloride/4-chlorophenol (1:2)) was developed for extraction/preconcentration of trace levels of pesticides. The sorbent was characterized using scanning electron microscopy, Fourier transform infrared spectroscopy, and vibrating sample magnetometry. In-syringe magnetic dispersive solid-phase extraction in tandem with dispersive liquid-liquid microextraction followed by gas chromatography was applied for the analysis of the selected pesticides. The main parameters governing sample preparation efficiency, including adsorbent dosage, desorption conditions, pH, extraction time, deep eutectic solvent volume, and salt concentration, were investigated. The linear ranges were 0.024-500 µg L-1 with 0.9971-0.9999 linearity factor (R2 ). The limits of detection and quantification were 0.006-0.038 and 0.024-0.126 µg L-1 , respectively. The relative standard deviations were 0.5-4.2% for intra-day analysis and 2.7-4.6% for inter-day analysis. Enrichment factors were in the range 210-540. CONCLUSIONS: The method was successfully applied for the determination of malathion, heptachlor epoxide, endrin, dichlorodiphenyltrichloroethane, azinphos ethyl, cypermethrin, and deltamethrin in fruit juice samples (apple, pineapple, cherry, peach, and red and green grape juices) and the recoveries were within the range 71-115%. © 2020 Society of Chemical Industry.

New magnetic oil palm fiber activated carbon-reinforced polypyrrole solid phase extraction combined with gas chromatography-electron capture detection for determination of organochlorine pesticides in water samples.

Magnetic solid phase extraction (MSPE) employing oil-palm fiber activated carbon (OPAC) modified with magnetite (Fe3O4) and polypyrrole (OPAC-Fe3O4-PPy) was successfully used for the determination of two organochlorine pesticides (OCPs), namely endosulfan and dieldrin in environmental water samples. Analysis was performed using gas chromatography with micro-electron capture detection (GC-µECD). The effects of three preparation variables, namely Fe3O4:OPAC ratio, amount of pyrrole monomer, and amount of FeCl3 oxidant were optimized using Box-Behnken design (BBD) (R2 < 0.99, p-value < 0.001%). The optimum conditions were as follows: Fe3O4:OPAC ratio of 2:1 w/w, 1 g of FeCl3 and 100 µL of pyrrole monomer. The experimental results obtained agreed satisfactorily with the model prediction (> 90% agreement). Optimized OPAC-Fe3O4-PPy composite was characterized using field emission scanning electron microscope, vibrating sample magnetometer and Fourier transform infrared spectroscopy. Four numerical parameters of MSPE procedure was optimized using BBD. The significance of the MSPE parameters were salt addition > sample solution pH > extraction time and desorption time. Under the optimized conditions (extraction time: 90 s, desorption time: 10 min, salt: 0%, and pH: 5.8), the method demonstrated good linearity (25-1000 ng L-1) with coefficients of determination, R2 > 0.991, and low detection limits for both endosulfan (7.3 ng L-1) and dieldrin (8.6 ng L-1). The method showed high analyte recoveries in the range of 98.6-103.5% for environmental water samples. The proposed OPAC-Fe3O4-PPy MSPE method offered good features such as sustainability, simplicity, and rapid extraction.

New effective 3-aminopropyltrimethoxysilane functionalized magnetic sporopollenin-based silica coated graphene oxide adsorbent for removal of Pb(II) from aqueous environment.

A new effective adsorbent, 3-aminopropyltrimethoxysilane functionalized magnetic sporopollenin (MSp@SiO2NH2) based silica-coated graphene oxide (GO), (GO@SiO2-MSp@SiO2NH2) was successfully synthesized and applied for the first time in the removal of hazardous Pb(II) ions from aqueous solution. The properties of the composite were characterized using Fourier-transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), field emission scanning electron microscopy (FESEM), energy-dispersive X-ray spectroscopy (EDX) and vibrating-sample magnetometery (VSM). Evaluation of GO@SiO2-MSp@SiO2NH2 adsorption performance at optimum conditions revealed that the adsorbent has a maximum adsorption capacity of 323.5 mg/g for Pb(II) using 50-200 mg/L initial Pb(II) ions concentrations. Initial and final concentrations of Pb(II) ions in aqueous solution were analyzed using graphite furnace atomic absorption spectroscopy (GF-ASS). The adsorption behavior of Pb(II) ions onto GO@SiO2-MSp@SiO2NH2 was studied using Langmuir, Freundlich and Temkin isotherms models. The values of coefficient of determination showed that the adsorption best fitted the Langmuir model (R2 = 0.9994). Kinetic studies suggested that the adsorption of Pb(II) ion followed a pseudo-second-order rate model (R2 = 1.00) and thermodynamic studies revealed that the adsorption process is endothermic and spontaneous. The effect of co-existing ions on Pb(II) ion adsorption were also studied and found to have considerable effects only at higher matrix concentration. The adsorbent can be reused up to ten times and retain its good adsorption capacity. In addition, GO@SiO2-MSp@SiO2NH2 showed great potential for Pb(II)removal from industrial wastewater samples.

Determination of cholecalciferol (vitamin D3) in bovine milk by dispersive micro-solid phase extraction based on the magnetic three-dimensional graphene-sporopollenin sorbent.

In this research, a new magnetic sorbent material composed of three-dimensional graphene aerogel decorated with Fe3O4 nanoparticles attached to hollow sporopollenin exine capsules was synthesized and applied for extraction of vitamin D3 before HPLC-UV analysis. The adsorbent was characterized by FT-IR, SEM, VSM, and zeta potential techniques. The important parameters of the extraction process, including adsorbent dosage, desorption conditions, adsorption time, pH, and salt concentration, were investigated. Under the optimized condition, the method analytical figures of merit were evaluated as follows: linear dynamic range, 10-500 µg L-1; limit of detection, 3.01 µg L-1; determination coefficient (R2), 0.9960; intra-day RSD, 5.28%; and inter-day RSD, 8.17%. The applicability of the method was assessed for the determination of vitamin D3 in different unfortified and fortified bovine milk samples, and the recoveries in the 71.8-113.3% range with the RSDs within 1.4-7.0% were obtained.

Equilibrium, kinetic and thermodynamic study of pesticides removal from water using novel glucamine-calix[4]arene functionalized magnetic graphene oxide.

A novel nanocomposite of MGO-NGC, composed of magnetic Fe3O4 nanoparticles (M), graphene oxide (GO), and N-methyl-d-glucamine functionalized calix[4]arene (NGC), was synthesized and applied as an effective adsorbent for the removal of two selected pesticides, namely hexaconazole and chlorpyrifos from water samples. The adsorbent was characterized by FTIR, SEM, EDX, TEM, and XRD. The main parameters affecting the adsorption process such as adsorbent dosage, pH of sample solution, salt effect, pesticide concentration, and adsorption time were investigated. The data from kinetic studies fitted well to the pseudo-second order kinetic model with R2 > 0.99. Among the isotherm models of Langmuir, Freundlich, Temkin, and Dubinin-Radushkevich, the Langmuir isotherm fitted well to the adsorption process and demonstrated the monolayer adsorption pattern of the pesticides. Moreover, high adsorption capacities of 78.74 and 93.46 mg g-1 were obtained for chlorpyrifos and hexaconazole, respectively. Thermodynamic and free energy data indicated the physisorption mechanism for the adsorption process. The new adsorbent can be employed as an efficient, environment friendly, and highly reusable alternative for the removal of chlorinated pesticides from aqueous media.

Novel magnetic graphene oxide functionalized cyanopropyl nanocomposite as an adsorbent for the removal of Pb(II) ions from aqueous media: equilibrium and kinetic studies.

This work presents the synthesis of the novel silica-cyanopropyl functionalized magnetic graphene oxide (MGO/SiO2-CN) hybrid nanomaterial derived by sol-gel method as a cheap efficient magnetic sorbent for the removal of extremely hazardous lead ions from aqueous media. The integration of the magnetic property, the carbon substrate, and the nitrile (-C ≡ N) containing organic grafted silica matrix promoted the adsorption capability against lead ions along with its simple synthesis recovery and low cost. The prepared nanocomposite was comprehensively characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, and energy-dispersive X-ray spectroscopy. Adsorption of lead was found to be pH dependent because of the charged nature of both analyte and adsorbent surface. Adsorption experiments were conducted under the optimum conditions, and the obtained experimental data from atomic absorption spectroscopy were analyzed using the popular isothermal models namely Langmuir, Freundlich, and Dubinin-Radushkevich isotherms as well as kinetically studied and evaluated for adsorption standard free energy (E). The experimental results have demonstrated the enhanced adsorption capability of the proposed sorbent nanocomposite for lead ion removal with the maximum adsorption capacity of 111.11 mg/g at pH 5.0. The proposed mechanism of lead adsorption was mainly attributed to the complexation of lead positive ions with the grafted -C ≡ N bond. The synergistic effect of the combination of three components (i.e., the magnetic graphene oxide matrix, the triple bond containing organic moiety, and the inorganic porous silica framework) excelled the adsorption capability and proved to be a good candidate as adsorbent for the removal of lead ions.

Silica-based magnetic hybrid nanocomposite for the extraction and preconcentration of some organophosphorus pesticides before gas chromatography.

The precise control of pesticide residues in foodstuffs depends significantly on the clean extraction of analytes using specifically designed separation methods. In this study, a one-pot sol-gel process was used for the preparation of a magnetic hybrid silica gel tetraethylortho silicate-cyanopropyltriethoxy silane nanocomposite. The prepared material was characterized using energy dispersive X-ray spectroscopy, Fourier transform infrared spectroscopy, single-point specific surface area, and scanning electron microcopy. The synthesized magnetic hybrid material was used as a solid phase extraction sorbent for the extraction and preconcentration of some organophosphorus pesticides before gas chromatography with a microelectron capture detector. The performance of the proposed magnetic solid-phase extraction technique was validated by linearity (0.05-2 ng/mL), correlation coefficients (r2  = 0.9993-0.9997), limit of detection (0.02-0.06 ng/mL, S/N = 3, n = 3), and intraday (RSD = 1.5-8.7%, n = 3) and interday precision (RSD = 5.5-9.3%, n = 12), while the recovery in real samples and equilibrium adsorption capacity was 72.02-103.84% and 8-20 mg/g, respectively. The magnetic solid-phase extraction based on the hybrid nanocomposite revealed a high enrichment factor, an appropriate dynamic range, and great absorptive ability toward the selected organophosphorus pesticides spiked in real water samples.

Synthesis of piperazine functionalized magnetic sporopollenin: a new organic-inorganic hybrid material for the removal of lead(II) and arsenic(III) from aqueous solution.

The present work describes the successful functionalization/magnetization of bio-polymeric spores of Lycopodium clavatum (sporopollenin) with 1-(2-hydroxyethyl) piperazine. Analytical techniques, i.e., Fourier transform infrared (FT-IR), field emission scanning electron microscope (FESEM), energy-dispersive X-ray spectroscopy (EDS), and vibrating sample magnetometer (VSM), were used to confirm the formation of 1-(2-hydroxyethyl) piperazine-functionalized magnetic sporopollenin (MNPs-Sp-HEP). The proposed adsorbent (MNPs-Sp-HEP) was used for the removal of noxious Pb(II) and As(III) metal ions from aqueous media through a batch-wise method. Different experimental parameters were optimized for the effective removal of selected noxious metal ions. Maximum adsorption capacity (q m ) 13.36 and 69.85 mg g-1 for Pb(II) and As(III), respectively, were obtained. Thermodynamic parameters such as free energy (ΔG°), entropy (ΔS°), and enthalpy (ΔH°) were also studied from the adsorption results and were used to elaborate the mechanism of their confiscation. The obtained results indicated that newly adsorbent can be successfully applied for the decontamination of noxious Pb(II) and As(III) from the aqueous environment.

Novel Palm Fatty Acid Functionalized Magnetite Nanoparticles for Magnetic Solid-Phase Extraction of Trace Polycyclic Aromatic Hydrocarbons from Environmental Samples.

A novel adsorbent, palm fatty acid coated magnetic Fe3O4 nanoparticles (MNP-FA) was successfully synthesized with immobilization of the palm fatty acid onto the surface of MNPs. The successful synthesis of MNP-FA was further confirmed by X-Ray diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR) and Energy dispersive X-Ray spectroscopy (EDX) analyses and water contact angle (WCA) measurement. This newly synthesized MNP-FA was applied as magnetic solid phase extraction (MSPE) adsorbent for the enrichment of polycyclic aromatic hydrocarbons (PAHs), namely fluoranthene (FLT), pyrene (Pyr), chrysene (Cry) and benzo(a)pyrene (BaP) from environmental samples prior to High Performance Liquid Chromatography- Diode Array Detector (HPLC-DAD) analysis. The MSPE method was optimized by several parameters such as amount of sorbent, desorption solvent, volume of desorption solvent, extraction time, desorption time, pH and sample volume. Under the optimized conditions, MSPE method provided a low detection limit (LOD) for FLT, Pyr, Cry and BaP in the range of 0.01-0.05 ng mL-1. The PAHs recoveries of the spiked leachate samples ranged from 98.5% to 113.8% with the RSDs (n = 5) ranging from 3.5% to 12.2%, while for the spiked sludge samples, the recoveries ranged from 81.1% to 119.3% with the RSDs (n = 5) ranging from 3.1% to 13.6%. The recyclability study revealed that MNP-FA has excellent reusability up to five times. Chromatrographic analysis demonstrated the suitability of MNP-FA as MSPE adsorbent for the efficient extraction of PAHs from environmental samples.

Graphene-Based Materials as Solid Phase Extraction Sorbent for Trace Metal Ions, Organic Compounds, and Biological Sample Preparation.

Graphene is a new carbon-based material that is of interest in separation science. Graphene has extraordinary properties including nano size, high surface area, thermal and chemical stability, and excellent adsorption affinity to pollutants. Its adsorption mechanisms are through non-covalent interactions (π-π stacking, electrostatic interactions, and H-bonding) for organic compounds and covalent interactions for metal ions. These properties have led to graphene-based material becoming a desirable adsorbent in a popular sample preparation technique known as solid phase extraction (SPE). Numerous studies have been published on graphene applications in recent years, but few review papers have focused on its applications in analytical chemistry. This article focuses on recent preconcentration of trace elements, organic compounds, and biological species using SPE-based graphene, graphene oxide, and their modified forms. Solid phase microextraction and micro SPE (µSPE) methods based on graphene are discussed.

Magnetic solid-phase extraction based on modified ferum oxides for enrichment, preconcentration, and isolation of pesticides and selected pollutants.

Recently, a simple, rapid, high-efficiency, selective, and sensitive method for isolation, preconcentration, and enrichment of analytes has been developed. This new method of sample handling is based on ferum oxides as magnetic nanoparticles (MNPs) and has been used for magnetic solid-phase extraction (MSPE) of various analytes from various matrices. This review focuses on the applications of modified ferum oxides, especially modified Fe3O4 MNPs, as MSPE adsorbent for pesticide isolation from various matrices. Further perspectives on MSPE based on modified Fe3O4 for inorganic metal ions, organic compounds, and biological species from water samples are also presented. Ferum(III) oxide MNPs (Fe2O3) are also highlighted.