A new analytical approach for preconcentration, separation and determination of Pb(II) and Cd(II) in real samples using a new adsorbent: Synthesis, characterization and application

Hydrophilic magnetic chitosan/gelatin hydrogel with enhanced fuel dehydration characteristics: Modeling, kinetic, isotherm and thermodynamic study

In this research, a nanocomposite of Fe3O4/chitosan/gelatin was prepared and used as a magnetic recyclable dewatering agent to improve the quality of fuel. Prepared materials were characterized by XRD, FT-IR, VSM, BET and FESEM techniques. Effective factors on water uptake i.e., initial water content, time, percentage of Fe3O4 and adsorbent dosage were optimized with Box-Behnken design and results showed that all parameters are significant. The performances of three magnetic composites including crosslinked chitosan, functionalized chitosan and chitosan/gelatin showed that magnetic chitosan/gelatin with 13 % of Fe3O4 content has a removal percentage of 99.2-97.3 % besides the efficiencies were 35.8-43.8 % and 79.5-89 % using crosslinked chitosan, functionalized chitosan as adsorbents. Results from the kinetic study showed that pseudo - second-order model can better describe water uptake moreover, the adsorption process followed the Langmuir isotherm model. Magnetic chitosan/gelatin composite shows a maximum water removal efficiency of 97.3 % at an initial water concentration of 2500 mgL-1 after 40 min. The thermodynamic study showed that adsorption is a spontaneous process with higher feasibility at higher temperatures. Moreover, the adsorbent shows a good efficiency of 93.7 % after 6 recycling. These results confirmed good performances of the prepared hydrogel in dehydration to improve the quality of fuel.

Extraction and preconcentration of lead (II) in various water and food samples by orbital shaker-assisted magnetic solid phase extraction method using a new magnetic poly linoleic acid-polystyrene-PDMS block copolymer

The aim of this study was to develop a practical orbital shaker-assisted magnetic solid phase extraction (OSA-MSPE) method for the determination of lead by FAAS. A new magnetic poly linoleic acid-polystyrene-polydimethylsiloxane (PSt-PLina-PDMS) hydrophobic graft copolymer was synthesized and characterized by NMR, FT-IR, SEM-EDX, DSC, TGA, BET and used as adsorbent for the extraction of Pb (II). This adsorbent can be used at least 50 times without any decrease of its adsorption properties for the adsorption and elution of analyte ions. Several analytical parameters including pH, adsorbent amount, sample volume, shaking time, etc. were optimized. Multivariate optimization was used for the investigation of different parameters. The linear range at optimum operating condition was 1.7-84 μg L-1. The limit of detection (LOD) and limit of quantification (LOQ) were 0.5 μg L-1, 1.7 μg L-1, respectively. Intraday and interday relative standard deviation (RSD %), enhancement factor (EF) and adsorbent capacity were found as 1.9%, 3.3%, 166.7, 50 mg g-1, respectively. OSA-MSPE method was tested with certified reference materials including LGC-6010 (Hard Drinking Water), NCS ZC73032 Celery and CS-M-3 Control Sample Microelements in Mushroom Powder for the accuracy. Experimental results for lead were confirmed with certified values. Present method was successfully applied to various liquid and solid food samples. The OSA-MSPE method has some important features such as selective, sensitive, low LOD, LOQ and RSD, pre-concentration factor (PF) and high enhancement factor (EF). High tolerance limits against matrix ions were achieved.

Functionalized porous carbon microspheres packed column for solid phase extraction and preconcentration of trace metal ions in food and water samples

Porous materials play a crucial role in the extraction of trace analytes; yet, the attainment of high selectivity and efficient regeneration continues to pose a considerable problem. In this study, we employed a green method to synthesize porous carbon microspheres. These microspheres were subsequently functionalized with aminophosphonic acid to facilitate the extraction of heavy metal ions from real samples. A comprehensive analysis of the aminomethylphosphorylated carbon microspheres was conducted using FTIR, SEM, EDX, TEM, BET and water contact angle measuring techniques. The potential optimization of analyte enrichment can be accomplished by the proposed solid-phase extraction (SPE) approach, which notably reduces spectrum interferences following sample purification. Following the IUPAC equation, the detection limit of the proposed method was found to be 0.04 ng mL-1, after running 20 replicate blank tests. The primary focus of sequestration of trace metal ions is the formation of metal-ligand chelates within the carbon spheres, resulting in enhanced selectivity and extraction rates exceeding 99.9% from samples with low concentrations. The present studies show a significant preconcentration limit of 0.4 ng mL-1 and a substantial preconcentration factor of 500. The method was implemented to examine real food and water samples, and the obtained data exhibit significant accuracy with a relative standard deviation (RSD) of less than 5%.

CoSn(OH)6 nanocubes as a solid sorbent for the effective preconcentration of copper ions in cinnamon (Cinnamomum zeylanicum) extract

This study was aimed at developing a simple and efficient CoSn(OH)6 nanocubes-based preconcentration method for the preconcentration of copper ions from cinnamon extracts for determination by flame atomic absorption spectrometry. The cube-shaped sorbent was synthesized using the simple stoichiometric co-precipitation method under ambient conditions. Experimental factors of the method were evaluated with a comprehensive optimization approach to maximize the extraction efficiency for the analyte. Under the optimal conditions, the limit of detection (LOD), limit of quantitation (LOQ), and linear dynamic range were recorded as 0.98 µg/L, 3.28 µg/L, and 4.0-75 µg/L, respectively. The enhancement factor was calculated as 101.6-fold by comparing the LODs of the optimized and direct analysis systems. Percent recoveries were found to be within an acceptable range (77.6-115 %), with high repeatability using matrix matching calibration strategy. Results validated the proposed method as a highly efficient extraction approach for the monitoring of copper ions in herbal cinnamon extracts.

Synthesis of ionically imprinted Poly(Alylthiourea) in the presence of 1-(2-Pyridylazo)-2-Napthol (PAN) for preconcentration in magnetic dispersive solid phase of nickel ions in water and food samples

In the present study, a magnetic ion-imprinted polymer based on n-allylthiourea in the presence of 1-(2-pyridylazo)-2-naphthol (MIIP-PAN) was synthesized, characterized, and applied in the preconcentration of nickel ions by dispersive magnetic solid phase extraction (DMSPE) with FAAS detection. For comparison, non-imprinted polymer (MNIP-PAN) and imprinted polymer without PAN were synthesized. The characterization of the polymers was performed by FT-IR, DRX, TEM, TGA, VSM, and BET. Selectivity studies were performed comparing the competitive adsorption of Ni2+ with other cations on MIIP-PAN and MNIP-PAN, achieving higher relative selectivity coefficients for MIIP-PAN than for MNIP-PAN and NIP. Under optimized conditions, the method provided a preconcentration factor of 76.70, detection limit of 0.25 µg/L and intra-day (2.06 - 2.33 %) and inter-day (1.82 - 4.90 %) precision. The developed method was applied to samples of water, teas, and chocolate powder, and its precision was evaluated through tests of recovery and analysis of certified materials.

Evaluation of Trace Elements in Coffee and Mixed Coffee Samples Using ICP-OES Method

This research examines the concentration of 10 trace elements including arsenic (As), lead (Pb), chromium (Cr), zinc (Zn), iron (Fe), cobalt (Co), cadmium (Cd), nickel (Ni), manganese (Mn), and aluminum (Al) from among 36 different samples of coffee (3 brands and 2 types of simple and instant) and mixed coffee (3 brands and 4 types of simple, creamy, chocolate and sugar free) collected from market of Iran's and analyzed by using ICP-OES (inductively coupled plasma-optical emission spectrometry). The recovery, limit of quantification (LOQ), and limit of detection (LOD) ranged from 93.4 to 103.1%, 0.06 to 7.22, and 0.018 to 2.166 µg/kg, respectively. The findings showed that the highest and lowest average concentrations were 498.72 ± 23.07 μg/kg (Fe) and 3.01 ± 1.30 μg/kg (As) in coffee and mixed coffee samples. Also, in all samples, the maximum concentration of trace elements was related to Fe (1353.61 µg/kg) and the minimum concentration was related to Al, As, Co, Cr, Ni, Pb, and Zn that were not detected (ND). The samples of mixed coffee had highest levels of trace elements compared to coffee samples. In coffee samples, type of instant coffee had highest levels of trace elements compared to simple coffee and mixed coffee samples. The type of creamy mixed coffee had highest levels of trace elements (except Ni and Cr) compared to other type of mixed coffee samples. Finally, trace elements were less than the standard levels of Iran and other countries (in all samples); therefore, it does not threaten Iranian consumers.

A novel fluorescent "Off-On" probe based on phenanthro[9,10-d]imidazole conjugated polymers (PIPF) for Cr3+ detection with high selectivity and sensitivity

Trivalent chromium (Cr3+) causes serious environmental pollution, degradation of the quality of edible agricultural products and human diseases. A novel phenanthro[9,10-d]imidazole-derived conjugated polymers (PIPF) was obtained from 4-(5,10-dibromo-1H-phenanthro[9,10-d]imidazol-2-yl)phenol and diethyl 4,4'-(2,7-bis(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-9H-fluorene-9,9-diyl)dibutyrate by Suzuki polymerization reaction, which was reasonably demonstrated by 1H NMR spectroscopy, infrared spectroscopy and quantum chemical calculations. The PIPF exhibits a "turn-on" fluorescence response to Cr3+ in DMSO/H2O (98:2, v/v) with naked-eye detection. The limit of detection for Cr3+ was calculated to be 0.073 μM with a linear range of 3-9 μM. The possible mechanism of the PIPF-based Cr3+ fluorescence "turn-on" sensor is due to the inhibition of the PET process by the coordination of Cr3+ to the hexaalkyl ester carbon chain of PIPF (RCOO-). The high sensitivity, good selectivity, and utility of this sensor indicated that PIPF-based "turn-on" fluorescence sensor is a potential fluorescence application for measuring Cr3+ in environmental samples.

An automatic and smart platform for rapid detection of cadmium and lead simultaneously in rice using triple-amplified chemiluminescence immunoassay

Rapid detection of trace ions is urgently needed for large-scale screening to ensure food safety. This study developed an innovative and automatic strategy, based on a smart-designed platform for rapid detection of cadmium and lead in rice. As bridge antibody, the antigen was conjugated with goat anti-mouse immunoglobulin G labeled alkaline phosphatase. Meanwhile, a biotin-streptavidin system was introduced to micromagnetic particles, thus providing a triple-amplified chemiluminescence immunoassay with high sensitivity, accuracy and specificity. The limits of detection for cadmium and lead were 0.06 and 1.00 ng mL-1, respectively, within 30 min. The recoveries ranged from 89.81 to 114.92 %, with relative standard deviations less than 9.2 %. The results obtained agreed with those of inductively coupled plasma-mass spectrometry and certified reference materials. Additionally, the auto-operation avoided human errors as well as being convenient, fast, automatic and high-throughput. Therefore, this smart platform can be applied for large-scale Cd2+ and Pb2+ screening.

Selective removal of Pb(II) from yellow rice wine using magnetic carbon-based adsorbent

BACKGROUND

The non-distilled property and prolonged production period of yellow rice wine have significantly increased the metal residue problem, posing a threat to human health. In this study, a magnetic carbon-based adsorbent, named magnetic nitrogen-doped carbon (M-NC), was developed for the selective removal of lead(II) (Pb(II)) from yellow rice wine.

RESULTS

The results showed that the uniformly structured M-NC could be easily separated from the solution, exhibiting a high Pb(II) adsorption capacity of 121.86 mg g-1 . The proposed adsorption treatment showed significant Pb(II) removal efficiencies (91.42-98.90%) for yellow rice wines in 15 min without affecting their taste, odor, and physicochemical characteristics of the wines. The adsorption mechanism studied by X-ray photoelectron spectroscopy (XPS) and Fourier-transform infrared (FTIR) analyses indicated that the selective removal of Pb(II) could be attributed to the electrostatic interaction and covalent interaction between the empty orbital of Pb(II) and the π electrons of the N species on M-NC. Additionally, the M-NC showed no significant cytotoxicity on the Caco-2 cell lines.

CONCLUSION

Selective removal of Pb(II) from yellow rice wine was achieved using magnetic carbon-based adsorbent. This facile and recyclable adsorption operation could potentially address the challenge of toxic metal pollution in liquid foods. © 2023 Society of Chemical Industry.

Modified Polysulfone Nanofibers for the Extraction and Preconcentration of Lead from Aqueous Solutions

Since lead is a highly toxic metal, it is necessary to detect its presence in different samples; unfortunately, analysis can be complicated if the samples contain concentrations below the detection limit of conventional analytical techniques. Solid phase extraction is a technique that allows the carrying out of a pre-concentration process and thus makes it easy to quantify analytes. This work studied the efficiency of sorption and preconcentration of lead utilizing polysulfone (PSf) fibers grafted with acrylic acid (AA). The best conditions for Pb(II) extraction were: pH 5, 0.1 mol L^-1 of ionic strength, and 40 mg of sorbent (70% of removal). The sorbed Pb(II) was pre-concentrated by using an HNO₃ solution and quantified using flame atomic absorption spectrometry. The described procedure was used to obtain a correlation curve between initial concentrations and those obtained after the preconcentration process. This curve and the developed methodology were applied to the determination of Pb(II) concentration in a water sample contained in a handmade glazed clay vessel. With the implementation of the developed method, it was possible to pre-concentrate and determine a leached Pb(II) concentration of 258 µg L^-1.

A magnetic solid phase extraction procedure for Pb(II) at trace levels on magnetic Luffa@TiO2 in food and water samples

A novel magnetic Luffa@TiO₂ sorbent was synthesized and characterized by using XRD, FTIR and SEM techniques. Magnetic Luffa@TiO₂ was used for solid phase extraction of Pb(II) in food and water samples prior to its flame atomic absorption spectrometric (FAAS) detection. The analytical parameters such as pH, adsorbent quantity, type and volume of eluent, and foreign ions were optimized. Analytical features such as the limit of detection (LOD) and the limit of quantification (LOQ) of Pb(II) are 0.04 μg L^-1 and 0.13 μg L^-1 for liquid samples and 0.159 ng/g and 0.529 ng/g for solid samples, respectively. The preconcentration factor (PF) and relative standard deviation (RSD%) were found 50, and 4 % respectively. The method was validated by using three certified reference materials (NIST SRM 1577b bovine liver, TMDA-53.3 and TMDA-64.3fortified water). The presented method was applied to lead contents of some food and natural water samples.

In-situ formation of a solid adsorbent for the extraction of some metal ions from crude oil before their determination by microflow nebulizer inductively coupled plasma-mass spectrometry

The presence of heavy metals in crude oil can create different problems on the oil processing and devices as well as pollution of the environment. Establishment of sample preparation methods for the extraction of metals from crude oil is the bottleneck of a successful determination method due to high hydrophobicity and complexity of crude oil matrix. In this study, a dispersive solid phase extraction procedure was developed for the simultaneous extraction of sixteen metal ions based on in-situ formation of an adsorbent in the sample solution. For this purpose, a suitable amount of dithiooxamide was dissolved in an organic solvent and was injected into the sample solution. By this action, dithiooxamide was re-precipitated in the sample solution and adsorbed the ions. The solid particles were separated and then the ions were eluted by a few microliters of choline chloride: 5-amino-8-hydroxyquinoline deep eutectic solvent under sonication. The presented method was validated and broad linear ranges (7.56-50000 ng g^-1) were obtained for calibration curves with coefficient of determination ≥0.992. Acceptable limits of detection (0.003-2.32 ng g^-1) and quantification (0.009-7.56 ng g^-1) were achieved. Good precision (relative standard deviation less than or equal to 4.3% for intra and inter-day precisions) and acceptable extraction recoveries (66-91%) were also obtained. Seven crude oil samples were analyzed and ten metal ions were determined successfully. The method was compared with the methods reported in literature and it was found that the data obtained by this method were reliable and accurate.

Accurate Determination of Trace Cadmium in Soil Samples with Graphite Furnace Atomic Absorption Spectrometry Using Metal-Organic Frameworks as Matrix Modifiers

Cadmium (Cd) is a highly toxic heavy metal that is widely distributed in soils at low concentrations. Its volatilization loss occurs at an ashing temperature higher than 350 °C. Accordingly, the accurate determination of its concentration in soils often requires the addition of chemical modifiers by graphite furnace atomic absorption spectrometry (GFAAS) to improve the thermal stability of Cd. In this work, a metal-organic framework (MOF, UIO-66-NH₂) was utilized as a matrix modifier to improve accuracy in determining Cd in soils using GFAAS. The Cd signal, as influenced by drying and pyrolysis temperature and special gas, was also investigated, and the measuring conditions were optimized (2 μg L^-1 Cd concentrations, matrix modifier: UIO-66-NH₂, pyrolysis temperature: 550 °C, atomization temperature: 1650 °C, and special gas: air). The limit of detection (LOD) and the characteristic mass for Cd in soil were 3.84 ng g^-1 and 0.80 pg, respectively. Five soil standard reference materials (SRMs) were analyzed for Cd to verify the effectiveness of the optimized measuring conditions. The soil Cd concentrations obtained were in remarkable agreement with the reference values. Moreover, the mechanism of UIO-66-NH₂ on the graphite platform was investigated in the drying and pyrolysis steps by scanning electron microscopy (SEM), Fourier transform infrared (FT-IR), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). During the drying steps, many functional groups of the matrix were activated, and Cd²⁺ could be captured on its surface. After the pyrolysis step, the structure matrix collapsed and was partially decomposed into ZrO₂, and subsequently, an intermediate state of ZrO₂-(CdO) appeared at high temperatures, which came from the active binding sites on the zirconium oxide octahedron nodes.

Insights into brewed tea waste as a green and low-priced adsorbent for solid-phase extraction of Cd(II) ions: isotherm, kinetic, and artificial neural network approach

In the present research, brewed tea waste (BTW) was utilized as a green, low-priced, and abundant adsorbent for separation/preconcentration of Cd(II) ions through solid-phase extraction method from water and foods for the first time. BTW was applied as a natural adsorbent, without using any chelating agent to bind Cd(II) ions or any chemical reagent for its modification. A three-layer artificial neural network model using backpropagation algorithm was utilized to explicate a prediction model for the extraction performance of Cd(II) ions by selecting the input parameters as solution pH, quantity of BTW, sample volume, eluent concentration and volume, and equilibrium time for desorption. The preconcentration factor, relative standard deviation, and detection limit were attained as 100, 3.03%, and 0.56 µg L−1, respectively. It was decided that the Langmuir isotherm model is acceptable to characterize the retention of Cd(II) ions on BTW. This result pointed out that the active binding sites on the BTW surface are homogeneously distributed. Adsorption capacity of BTW was achieved as 41.5 mg g−1 which is higher than several expensive and difficult-to-prepare adsorbents. Adsorption kinetics was elucidated by pseudo-second order kinetic model. After confirmed the accuracy of the method with spike/recovery studies, it was employed for Cd(II) determination in water (stream and sea water) and food (eggplant, lettuce, parsley, apple, and apricot) samples with high accuracy. The inferences of the study proved that the BTW offers a magnificent application prospect in the extraction of Cd(II) ions.

Novel Graphene oxide-Polyethylene Glycol mono-4-nonylphenyl Ether adsorbent for solid phase extraction of Pb2+ in blood and water samples

A novel and efficient Graphene Oxide-Polyethylene Glycol mono-4-nonylphenyl Ether (GO-PEGPE) nanocomposite was synthesized and used for solid phase extraction of trace levels of Pb²⁺ in different water and blood samples. The synthesized adsorbent was then characterized by the Fourier Transform-Infrared spectrophotometry (FT-IR), Field Emission-Scanning Electron Microscopy (FE-SEM), Energy dispersive X-ray spectroscopy (EDX) and X-ray diffraction analysis (XRD). To optimize the critical parameters including pH of samples solution, amounts of adsorbent and extraction time, the response surface methodology based on the central composite design (RSM-CCD) was used and based on the results, pH = 6.0, extraction time = 22 min and amounts of adsorbent = 15 mg were selected as the optimum conditions. The relative standard deviation based on seven replicate analysis of 2 µg L^-1 Pb²⁺ was 5.2% and the limit of detection was 0.023 µg L^-1 (n = 8). The results of adsorption isotherm investigation show that the adsorption of Pb²⁺ onto the GO-PEGPE nanocomposite obeyed by the Langmuir isotherm with the maximum adsorption capacity of 69.44 mg g^-1. Also, based on the Temkin and Dubinin-Radushkevich (DR) isotherms, the adsorption of Pb²⁺ onto the GO-PEGPE nanocomposite is a physisorption phenomenon and the consequences of the kinetic models illustrated that the adsorption of Pb²⁺ followed by the pseudo second order adsorption kinetic model. Finally, the proposed method was successfully applied for preconcentration of Pb²⁺ in different water and blood samples of turning industry workers.

Ultrasonic-assisted dispersive liquid-liquid microextraction based on hydrophilic deep eutectic solvents: Application to lead and cadmium monitoring in water and food samples

A green and innovative ultrasonic-assisted dispersive liquid-liquid microextraction using hydrophilic deep eutectic solvents (UA-HDES-DLLME) was developed for the selective and simultaneous extraction and enrichment of Pb (II) and Cd (II) in water and food samples for flame atomic absorption spectrometry. Several natural deep eutectic solvents (NADES) were used for the preparation of six different HDES and methyl violet was used as chelating reagent. Effective parameters such as pH, sonication time, methyl violet amount, DES type, dispersive solvent types, etc were optimized. Relative standard deviation (RSD) and preconcentration factor (PF) were 4.0% and 80. Low limits of detection (LOD, 1.3 ng mL^-1 for Pb (II) and 0.33 ng mL^-1 for Cd (II)) and quantification (LOQ, 4.0 ng mL^-1 for Pb (II) and 1.0 ng mL^-1 for Cd (II)) were found. The method accuracy was confirmed with analyses of certified reference materials.

Toxic cadmium selective sequestration from food samples using melamine anchored magnetic cellulose by surface imprinting route

Cadmium is very toxic for living organisms hence selective and efficient control capturing of it is necessary. To reach this goal a novel imprinted polymer was developed using melamine anchored MnFe₂O₄ - cellulose. Magnetic cellulose was synthesized through an ultrasound-assisted precipitation route. Chloropropyltriethoxysilane was used to attach melamine to the magnetic cellulose surface. Response surface methodology employed to optimize effective parameters on cadmium adsorption. Time of 13 min, the dosage of 18 mg and pH of 8 was selected as optimum conditions. The relative standard deviation, detection limits and adsorption capacity were 2,5%, 0.50 µgL^-1 and 138 mg g^-1 respectively. The selectivity coefficient of Cd(II) relative to Cu(II), Co(II), Ni(II) and Pb(II) were 4, 5, 12 and 3, respectively. Regeneration of the sorbent was performed using HCl (0.5 mol L^-1) as eluent. The method was used for cadmium preconcentration in fish, lettuce and liver with satisfactory results.

Synthesis of green nano sorbents for simultaneous preconcentration and recovery of heavy metals from water

The wastewater containing Cd, Co, Fe, Cu, Cr, Mn, Ni and Pb ions are as trace metal pollutants. Water pollution caused by increment in industrialization and overpopulation reveals a major threat to human health. Adsorption is recognized as the effective and optimum method to remove water contaminations. The amorphous and porous form of silicon dioxide is silica gel widely used as an adsorbent. It can absorb moisture with traces of the target heavy metal ions. This research elaborates a simplistic, and reliable preconcentration column method highly developed for the determination of Cd²⁺, Fe³⁺, Co²⁺, Cr³⁺, Cu²⁺, Mn²⁺, Pb²⁺ and Ni²⁺ ions in model solutions and real water samples by flame atomic absorption spectrometry (FAAS). The proposed operation depends on the retention of the target ions from buffered model solutions on a silica gel filled up a column modified with vanadium(V) oxide sorbent followed by their desorption. SiO₂/V₂O₅ is an efficient adsorbent due to its low cost, eco-friendly and high availability. The adsorbent morphological and interfacial physicochemical characterization was done using scanning electron microscopy, and Fourier transmission infrared spectroscopy, respectively. The 2.92 value achieved for the point of zero charges supports the experimentation for the heavy metal efficient adsorption. Quantitative recoveries were achieved at pH 10 with 50 mg of SiO₂/V₂O₅ mass and adsorption capacity ranged from 28.96 μmol/g (Pb) to 214.86 μmol/g (Fe) with 1114.79 μmol/g in total. Simultaneous preconcentration effect was determined by the interference cations on the sorbent. The LOD varies from 8.42 to 50.56 μg/L and LOQ is achieved from 20.06 to 72.41 μg/L of 15 blank solutions. The developed preconcentration procedure was adequately implemented for the simultaneous analysis of eight metallic ions content in local river samples. The developed vanadium(V) oxide incorporated with silica gel is practicable as an economical and effective adsorbent to eliminate metallic ions from a liquid solution.

Determination of the Cadmium Ions from Aqueous Solution Using EDTA Functionalized Prunus Dulcis L. Peels by Solid-Phase Extraction Method

In the present study, Prunus Dulcis L. Peels was modified with ethylenedinitrilo tetraacetic acid and used as the sorbent for the preconcentration of Cd(II) ions from aqueous media. To characterize the sorbent, scanning electron microscopy-energy dispersive X-ray spectrometer and Fourier transform infrared spectrometer analysis were used. The optimum preconcentration conditions such as pH, eluent type, sample volume, sample flow rate and foreign ions effect were determined. The mean recovery and relative standard deviation values were found to be 100.7 ± 1.5 and 4.01% for Cd(II) ions. The capacity of the sorbent was obtained 277.8 mg g^-1 from the Langmuir isotherm model. The limit of detection was calculated as 0.216 µg L^-1 (P.F:40). In order to test the accuracy and applicability of the method, certified reference material and spiked water samples were analyzed. The results demonstrated good agreement with the certified values (relative error < 10%).

Experimental design of ligandless sonication-assisted liquid- phases microextraction based on hydrophobic deep eutectic solvents for accurate determination of Pb(II) and Cd(II) from waters and food samples at trace levels

A straightforward, accurate and efficient analytical procedure was developed by ligandless sonication-assisted liquid- phases microextraction based on hydrophobic deep eutectic solvents (SA-LPME-HDES) to trace toxic Pb(II) and Cd(II) in waters and foods. Optimization of the SA-LPME-HDES procedure was carried out by Box-Behnken design. Under optimum conditions, linear ranges for Pb(II) and Cd(II) were 0.8-350 (r²:0.9962) and 1.5-500 µg L^-1 (r²: 0.9937), respectively. Relative standard deviations (N = 5, 10 µg L^-1) were 1.4% for Pb(II) and 1.6% for Cd(II), respectively. Limits of detection were 0.24, and 0.46 µg L^-1, respectively. The accuracy was evaluated by the analysis of two certified reference materials and the results were to be in agreement with the certified values. The SA-LPME-HDES method was successfully applied to tap water, mineral water, river water, well-water, sesame, peanut, eggplant, corn, wheat, soy and cucumber. The SA-LPME-HDES method allows operational simplicity, green, and low cost when compared with some microextraction procedure.

Novel solid-phase microextraction fiber coatings: A review

The materials used for the fabrication of solid-phase microextraction fiber coatings in the past five years are summarized in the current review, including carbon, metal-organic frameworks, covalent organic frameworks, aerogel, polymer, ionic liquids/poly (ionic liquids), metal oxides, and natural materials. The preparation approaches of different coatings, such as sol-gel technique, in-situ growth, electrodeposition, and glue methods, are briefly reviewed together with the evolution of the supporting substrates. In addition, the limitations of the current coatings and the future development directions of solid-phase microextraction are presented.