Solid Phase Extraction Of Cadmium Research Articles

Fe3O4-Ti3AlC2 max phase impregnated with 2-(5-Bromo-2-pyridylazo-5-(diethylamino) phenol for magnetic solid phase extraction of Cadmium, lead and cobalt from water and food samples

In this work, we report the preparation of Fe3O4-Ti3AlC2 max phase impregnated with 2-(5-Bromo-2-pyridylazo-5-(diethylamino) phenol) and its implementation for the extraction of cadmium, lead and cobalt from water and food samples. Blended Fe3O4-Ti3AlC2 max phase impregnated with 2-(5-Bromo-2-pyridylazo-5-(diethylamino) phenol) was characterized using different instrumental techniques like scanning electron microscopy (SEM), surface area analyser (SAA), energy dispersive X-rays (EDX), Fourier transform infrared spectroscopy (FT-IR) and X-rays diffraction (XRD) for surface morphology, surface region, elemental composition, functional group and crystallinity, respectively. Factors that impact the % recoveries of analyte i.e pH, sample volume, vortex time, desorption condition and matrix impact were optimized. Analytical parameters like limit of detection (LOD) (Cd: 0.093 µg/L, Pb: 0.297 µg/L, Co: 0.223 µg/L), limit of quantifications (LOQ) (Cd: 0.310 µg/L, Pb: 0.992 µg/L, Co: 0.744 µg/L) preconcentration factors (PF) (Cd = Pb = Co: 40), enrichment factors (EF) (Cd: 39.8, Pb: 39, Co: 40) and relative standard deviation (RSD) (Cd: 3.8, Pb: 5.98, Co: 4.0) were determined under optimized trial conditions. The proposed strategy was tested using certified reference materials like TMDA-64.3 natural water and tobacco leaves (INCT-OBTL-5) for trace metal analysis. The developed strategy was also applied effectively to natural water samples and food samples using the standard addition method with good recovery results.

Selective and efficient solid phase extraction of cadmium (II) in sub-trace limits based on alizarin red-S cross-linked-2-mercapto-N-(3-(triethoxysilyl) propyl) acetamide bi-functionalized graphene oxide nanocomposite from different environmental water samples

A novel bi-functionalized nanocomposite based on graphene oxide-alizarin red-S cross-linked-2-mercapto-N-(3-(triethoxysilyl) propyl) acetamide (ARS-MTPS@GO) was developed for the sequestration of cadmium Cd(II) ions from water. The nanocomposite fabrication was characterized through different physicochemical techniques (FTIR, XRD, SEM, TEM, Raman, and TGA). In addition to its hydrophilicity, high surface area, and ability to interact with the functionalized moieties, the ARS-MTPS@GO nanocomposite has improved Cd(II) adsorption. An optimization study was carried out on various analytical parameters that affect cadmium extraction, including the pH, contact time, and nanocomposite mass dosage. The maximum sorption capacity and percentage removal efficiency of Cd(II) ions reached 222.7 mg g−1 and 99.4 ± 3.7%, respectively, at pH = 6 within 30 minutes and the pseudo-second-order kinetic model best fits the sorption rate. Validation of the proposed method was evaluated for nine replicate measurements for recovery of Cd(II), showed favorable analysis precision, and the estimated detection limit was 0.18 ± 0.02 ng mL−1. Additionally, the reusability and stability of the nanocomposite and the effects of interfering cations and anions were investigated. Finally, the developed method was successfully applied for the selective extraction of Cd(II) from environmental water samples of different matrices, and the Cd(II) recoveries were 96.2–99.2%±2.3%. This study’s findings prove the potential applicability of the novel nanocomposite for removing cadmium ions from different environmental waters.

Oilothermal, a novel pyrolysis method for fabrication of carbon dots-loaded carriers from cyanobacteria for use in solid-phase extraction of cadmium

BackgroundMaking carbon dots-loaded carriers (CLCs) required the use of two types of precursors (one for carrier particles and the other for carbon dots) and at least three steps. In this study, CLCs were fabricated by using cyanobacterial cells as a dual-purpose precursor and oilothermal as an innovative pyrolysis method. MethodsThe oilothermal method allowed that each cyanobacterial cell (carrier particle precursor) with its hydrous exopolysaccharides (EPSs) layer (carbon dots precursor) to be encapsulated together by an oil micelle and pyrolyzed separate from other cells and formed the CLC in one step. The potential of emerging CLCs for solid-phase extraction (SPE) was assessed. For this purpose, the CLCs were tested in a cadmium-based model. Significant findingsThe range of the maximum pH-dependent adsorption efficiency (>95%) was extensive (pH 4–10). The adsorption kinetics and isotherm had the best fit with the pseudo-second-order and Langmuir linear models, respectively. The adsorption capacity was 5305.61 mg kg−1 only in 2 min exposure time. The findings in this research conclude that emerging CLCs, because of their unique features such as high capacity, fast adsorption rate, fast recovery rate, green origin, optimal and efficient fabrication method, have a high potential for SPE of trace cadmium.

On-line Micro-Packed Column Solid-Phase Extraction of Cadmium Using Metal-Organic Framework (MOF) UiO-66 with Posterior Determination by TS-FF-AAS

Metal-organic framework (MOF) UiO-66 was synthesized and evaluated as solid-phase extractor support for cadmium preconcentration in a micro-flow injection system coupled to thermospray flame furnace atomic absorption spectrometry (TS-FF-AAS) detection. The adsorbent was characterized by X-ray diffraction, Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), Raman spectroscopy, and textural data from N2 adsorption/desorption isotherm data. The optimized conditions were achieved by loading 10.0 mL of a sample, containing 0.05 mol L-1 of phosphate buffer solution at pH 8.0, at a high flow rate of 10.0 mL-1 through 20.0 mg of UiO-66 packed into a mini-column, followed by elution with 1.0 mol L-1 HCl. At these conditions, the method presented a preconcentration factor of 35.7, limit of detection of 0.03 μg L-1 and a dynamic linear range from 0.1 to 8.0 μg L-1. The adsorption performance of UiO-66 towards cadmium was not influenced by Pb2+, Hg2+, Fe2+, Co2+, Cu2+, Ni2+, Zn2+, Mg2+ and Ca2+ ions. Analysis of different waters samples (tap water, physiological solution, mineral water, and lake water) was carried out without matrix interference, yielding recovery values ranging from 92.0 to 111.9%.

Micro solid phase extraction of cadmium and lead on a new ion-imprinted hierarchical mesoporous polymer via dual-template method in river water and fish muscles: Optimization by experimental design

In the present study, a new class of hierarchical silica based imprinted mesoporous polymers was fabricated by ion imprinting technology and it was applied to simultaneous selective extraction of cadmium and lead ions by micro solid phase extraction (μ-SPE). The biological nanocrystalline cellulose (BNCC) was prepared via acid catalyzed hydrolysis of cotton wool. The hierarchical silica (HS), as a substrate material, was synthesized via dual-template method, using BNCC and cetyltrimethylammonium bromide (CTAB) as hard and soft templates respectively. The structure and functional groups was characterized by Fourier infrared spectroscopy (FT-IR), transmission electron microscopy (TEM), X-ray diffraction (XRD) and nitrogen adsorption-desorption. The results indicate that the as-prepared material has a hierarchical mesoporous structure with high specific surface area and high adsorption capacity for Cd(II) and Pb(II). The optimum experimental conditions in the proposed procedure were determined by response surface methodology (RSM) based on Box Behnken Design (BBD) and then it was successfully applied to determine Cd(II) and Pb(II) ions in the river water and fish samples.

Saccharine based carbonyl multi-walled carbon nanotubes: novel modification, characterization and its ability for removing Cd(II) and Cu(II) from soil and environmental water samples

This research highlights the chemical modification of one of the carbon nanostructures (multi-walled carbon nanotubes-COOH) with an artificial sweetener (saccharine) to synthesize a highly efficient absorbent material (MWCNTs-CO-Sac). This material was thereafter used to the packing column in solid phase extraction of cadmium and copper divalent ions from real samples. This nano-adsorbent was diagnosed with different techniques: infrared spectroscopy (FTIR), Thermogravimetry (TG), Differential thermal analysis (DTA), powder X-ray diffraction (PXRD), energy-dispersive X-ray spectroscopy (EDX), Particle size distribution (PSD) and scanning electron microscopy (SEM). The effect of pH, sample and eluent flow rates, volume, type and concentration of eluent, volume of sample and interfering ions were studied to achieve the optimal conditions for solid phase extraction of Cd(II) and Cu(II) based on the inductively coupled plasma-optical emission spectrometry (ICP-OES). Moreover, the preconcentration factors were calculated to be 75. The results of a limit of detection (LOD) 0.07 μgL−1 and 0.09 μgL−1 for Cd(II) and Cu(II) respectively. The relative standard deviation (RSD %) of this study was 0.45% for Cd(II) and 0.51% for Cu(II). The optimized method was applied to soil and environmental water samples.

Magnetic solid phase extraction of cadmium and lead from water prior to FAAS determination: Which is better? Sorbent modification with organic acids or adding organic acids to the extraction medium

The purpose of the present work was to compare two protocols for magnetic solid phase extraction (MSPE) of cadmium (Cd(II)) and lead (Pb(II)) from aqueous medium prior to their determination by flame atomic absorption spectroscopy (FAAS). The first protocol (organic acid modification protocol) involved magnetite (Mag) and magnetic carbon nanotube (MCNT) modified by citric acid (cit), aspartic acid (asp) and ascorbic acid (asc). The magnetic adsorbents (MCNT, Mag, cit-MCNT, asp-MCNT, asc-MCNT, cit-Mag, asp-Mag, asc-Mag) were characterized using FTIR. Among all of the modified magnetic sorbents, cit-MCNT and asp-MCNT could be used for simultaneous extraction of metals at pH 8.2. The second protocol (organic acid addition protocol) involved Mag and MCNT in which citric acid, aspartic acid and ascorbic acid were added into the extraction medium. It was found that addition of any of the organic acids to the extraction medium reduced the performance of Mag towards Cd(II) but slightly improved its performance towards Pb(II). Addition of citric acid to the extraction medium using MCNT as extractant has a negative influence on Pb(II) extraction but has no influence on Cd(II) extraction. It was recommended to follow the first protocol using cit-MCNT as extractant. The optimum MSPE-FAAS method was achieved at pH 8.2 using 0.050 g cit-MCNT, shaking for 30 min, elution with 10 mL of 0.3 M HNO3. The figures of merit of the method were estimated. Application on real water samples gave the following spiked recovery (Cd(II) and Pb(II), respectively): tap water 73.3 ± 3.1 and 79.4 ± 6.9%; well water 72.2 ± 3.7 and 81.8 ± 3.4%.

Magnetic Mn2O3 nanocomposite covered with N,N'-bis(salicylidene)ethylenediamine for selective preconcentration of cadmium(II) prior to its quantification by FAAS.

This article describes a method for highly selective preconcentration of Cd(II) via magnetic Mn2O3 coated by N,N'-bis(salicylidene)ethylenediamine (BSED). The metal oxide components were prepared via combining sol-gel and precipitation methods. Then, BSED was added as the third component of the composite. X-ray diffraction, scanning electron microscopy, transmission electron microscopy, alternating gradient force magnetometry, and Fourier transform infrared spectroscopy were applied to characterize the materials. BSED selectively forms a complex with Cd(II), and the sorbent can then be magnetically separated. The preconcentration conditions were optimized as pH value (4.0 ± 0.5), sorbent amount (30mg), adsorption time (20min), eluent 2 MHNO3), eluent volume (1.5mL) and desorption time (4min). The quantification of Cd(II) was done by flame atomic absorption spectroscopy. Themethod has the following figures of merit: (a) a detection limit of 320µgL-1, (b) a relative standard deviation of 1.1%, (c) an enhancement factor of 36, (d) a preconcentration factor of 33, and (e) a linear dynamic range that extends from 10 to 120μgL-1. Other features include the use of safe reagents, fast and simple preparation, high selectivity and reliable analytical performance. The effects of potentially interfering ions were examined. The Dubinin-Radushkevich model and the pseudo second-order model are found to fit the adsorption behavior. The absorption is spontaneous and exothermic. The method was successfully applied to the determination of Cd(II) in (spiked) fruit samples. Graphical abstract Schematic presentation of a nanocomposite (Fe3O4 - Mn2O3 - Schiff base) that was prepared from MnCl2, H2O2, FeCl2, FeCl3, NH3, salicylaldehyde, ethylenediamine and tetraethylammonium hydroxide for the magnetic solid phase extraction of cadmium at trace levels.

Solid Phase Extraction of Cadmium and Lead from Water by Amberlyst 15 and Determination by Flame Atomic Absorption Spectrometry.

Preconcentration of Cd(II) and Pb(II) was carried out by using column solid phase extraction method. Amberlyst 15 was used as solid phase for these analytes. The optimum extraction conditions such as pH (4), type and volume of eluent (5mL of 2mol L-1 HNO3) sample flow rate (1mL min-1) and sample volume (100mL for Cd(II) and 750mL for Pb(II)) were determined. The recoveries were found for Cd(II) and Pb(II) as 104% ± 1% and 102 %± 2%, respectively. The limit of detections were found as 0.23µg L-1 for Cd(II) and 0.13µg L-1 for Pb(II). The effects of foreign ions were also studied. The method was validated by analyzing standard reference material and spiked water samples. Percent relative error and relative standard deviation were below 3% and 4%, respectively.

Synthesis and Application of Novel Magnetic Ion-Imprinted Polymers for Selective Solid Phase Extraction of Cadmium (II).

Ion-imprinted polymers (IIPs) have received much attention in the fields of separation and purification. Nevertheless, selectivity of IIPs for trace target ions in complicated matrix remains a challenge. In this work, a cadmium magnetic ion-imprinted polymer (MIIP) was synthesized via surface imprinting, using methacrylic acid and acrylamide as dual functional monomers, vinyltrimethoxysilane as ligand, Fe3O4@SiO2 as support, azodiisobutyronitrile as initiator, and ethylene glycol dimethacrylate as crosslinker. The MIIP was characterized by transmission electron microscopy, infrared spectroscopy, thermal gravimetric analysis, and a vibrating sample magnetometer. The maximum adsorption capacities of the MIIP and magnetic non-imprinted polymer for Cd(II) were 46.8 and 14.7 mg·g−1, respectively. The selectivity factors of Pb(II), Cu(II), and Ni(II) were 3.17, 2.97, and 2.57, respectively, which were greater than 1. The adsorption behavior of Cd(II) followed the Freundlich isotherm and a pseudo second order model. The MIIP was successfully used for the selective extraction and determination of trace Cd(II) in representative rice samples. The limit of detection and recovery of the method was 0.05 µg·L−1 and 80–103%, respectively, with a relative standard deviation less than 4.8%. This study shows that MIIP provides an attractive strategy for heavy metal detection.

Automatic solid phase extraction of cadmium exploiting a multicommutated flow system previous ICP-MS detection: Application to tobacco samples

A miniaturized automatic sample pre-treatment system, based on multicommutated flow techniques, i.e. Lab on Valve (LOV) and Multisyringe Flow Injection Analysis (MSFIA) techniques, for cadmium determination by ICP-MS in organic samples is presented. The on-line extraction and preconcentration system retains the analyte on the resin (Dowex 50W-X8), followed of elution with 1molL−1 HNO3. The LOV-MSFIA system allows the fully automation of solid phase renewal, which shown a durability of 130 injections without its replacement. The optimal operating conditions were investigated using multivariate optimization tools. The detection limit was 0.05ng of cadmium, while the mass linear working range was 0.2–100ng. The precision of the proposed methodology was 2.4% (RSD, n=10) with a sample frequency of 9 injections h−1.The accuracy of the method was established by means of an organic matrix certified reference material (DORM-2), and the method has been successfully applied to different samples of tobacco (commercial cigarettes, pipe tobacco and tobacco leaves), obtaining recoveries between 90 and 105%. Main advantages of the proposed methodology are a minimal sample handling, good precision, high stability of the column and the versatility achieved by a variety of managed sample volumes.

Fabrication of Fe3O4@graphene oxide core-shell nanospheres for ferrofluid-based dispersive solid phase extraction as exemplified for Cd(II) as a model analyte

The authors describe the synthesis of core-shell structured Fe3O4@graphene oxide nanospheres (denoted as Fe3O4@GO NSs) via a chemical (covalent) bonding method. A chemical method was applied to cutting graphene oxide flakes into GO nanosheets. These were then covalently immobilized onto the surface of magnetite (Fe3O4) nanoparticles. The material was characterized by TEM, SEM, EDX, FTIR, vibrating sample magnetometry and Raman spectroscopy. The data confirmed the coexistence of Fe3O4 and GO nanosheets with a core-shell structure. The Fe3O4@GO NSs were applied to ferrofluid-based dispersive solid phase extraction of cadmium(II) as a model analyte using an ionic liquid carrier. This sorbent possesses as large contact surface area and a high density of polar groups on its surface. The nanoparticles, when finely dispersed in the sample solution, result in almost complete extraction of Cd(II) within a few seconds. Cd(II) was then quantified by FAAS. Under optimized conditions, the assay has the following features: (a) A detection limit of 0.12 ng mL−1, (b) a preconcentration factor of 250, (c) a relative standard deviation of 1.4 % (at a level of 50 ng mL−1; for n = 10); (d) a linear analytical range extending from 0.4 to 150 ng mL−1, (e) a maximal adsorption capacity of 33.7 mg g−1, and (e) a well expressed Langmuir adsorption isotherm.

Sulfonated metal organic framework loaded on iron oxide nanoparticles as a new sorbent for the magnetic solid phase extraction of cadmium from environmental water samples

A sulfonated metal organic framework loaded onto iron oxide nanoparticles was used as a new sorbent and a magnetic solid phase extraction method was developed for the separation and preconcentration of cadmium prior to its determination by flame atomic absorption spectrometry.

Facile synthesis of cysteine functionalized magnetic graphene oxide nanosheets: Application in solid phase extraction of cadmium from environmental sample

A facile method for synthesis of cysteine functionalized magnetic graphene oxide nanosheets is introduced. In comparison with other metal ions, cysteine has more affinity to coordinate with cadmium, therefore, the modified graphene oxide nanosheets were used as a selective sorbent for solid-phase extraction and determination of trace cadmium in different food samples (rice, wheat, milk and shrimp). Satisfactory recoveries were obtained by using 0.8mgmL−1 of sorbent in a pH range of 5–9. The results showed good adsorption capacities (24.39–30.30mgg−1 at 298–328K) of the adsorbent with the high selectivity toward cadmium ions. The process was relatively fast and the equilibrium was established within 5min and its kinetics followed the pseudo-second order mechanism. The best interpretation for the equilibrium data was given by Langmuir isotherm and the thermodynamic parameters showed that the adsorption process was spontaneous, endothermic and chemical in nature.

Ultrasound-assisted dispersive solid phase extraction of cadmium(II) and lead(II) using a hybrid nanoadsorbent composed of graphene and the zeolite clinoptilolite

We describe a hybrid nanoadsorbent prepared by depositing graphene on the zeolite clinoptilolite by chemical vapor deposition. The resulting sorbent is well suited for the preconcentration of lead(II) and cadmium(II) by ultrasound-assisted dispersive micro solid–phase extraction. An extraction unit has been designed and manufactured that facilitates handling of small sample volumes. The effects of sample pH, amount of sorbent, concentration and volume of elution and time of ultrasonic bath were investigated. The nanoadsorbent was characterized by scanning electron microscopy, X-ray diffraction and energy dispersive X-ray microanalysis, all of which revealed the high surface area of the graphene sheets on the clinoptilolite. The extraction recoveries when using the new nanoadsorbent are 97 % (as opposed to a mere 10 % in case of clinoptilolite only). It is assumed that the graphene sheets located around the porous structure of clinoptilolite are acting as a barrier against macromolecules potentially existing in the sample matrices. The method was applied to the determination of lead and cadmium in water and human serum samples by electrothermal atomic absorption spectrometry. The detection limits were as low as 70 and 4 ng L−1 for Pb(II) and Cd(II), respectively. The accuracy of the method was underpinned by correct analysis of a standard reference material (SRM: 203105 Seronorm Trace Elements Serum L-2). New nanoadsorbent, graphene/ clinoptilolite hybrid, was prepared which is suitable for separating and preconcentrating the metal ions from biological samples. In the propose method, the synthesized G/CL nanoadsorbent was used in ultrasound- assisted dispersive micro solid phase extraction method with applying the new designed extraction unit.

Functionalization of cross linked chitosan with 2-aminopyridine-3-carboxylic acid for solid phase extraction of cadmium and zinc ions and their determination by atomic absorption spectrometry

We have developed a new method for solid phase extraction (SPE) and preconcentration of trace amounts of cadmium and zinc using cross linked chitosan that was functionalized with 2-aminopyridine-3-carboxy acid. Analytical parameters, sample pH, effect of flow rate, sample volume, and concentration of eluent on column SPE were investigated. The effect of matrix ions on the recovery of cadmium and zinc has been investigated and were found not to interfere with preconcentration. Under the optimum experimental conditions, the preconcentration factors for Cd(II) and Zn(II) were found to be 90. The two elements were quantified via atomic absorption spectrometry. The detection limits for cadmium and zinc are 21 and 65 ng L−1, respectively. The method was evaluated by analyzing a certified reference material (NIST 1643e; water) and has been successfully applied to the analysis of cadmium and zinc in environmental water samples.

Solid phase extraction of cadmium on 2-mercaptobenzothiazole loaded on sulfur powder in the medium of ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate and cold vapor generation–atomic absorption spectrometric determination

A novel solid phase extractor for preconcentration of cadmium at ng L −1 levels has been developed. Cadmium ions were retained on a column packed with sulfur powder modified with 2-mercaptobenzothiazole (2-MBT) in the medium of 1-butyl-3-methylimidazolium hexafluorophosphate ([bmim] +PF 6 −) ionic liquid. The presence of ionic liquid during modification of sulfur enhanced the retention of cadmium ions on the column. The retained cadmium ions were eluted with 2 mol L −1 solution of HCl and measured by cold vapor generation–atomic absorption spectrometry (CVG–AAS). By using reaction cell-gas liquid separator (RC-GLS), gaseous cadmium vapors were produced and reached the atomic absorption spectrometer, instantaneously. The influence of different variables on both processes of solid phase extraction and CVG–AAS determination of cadmium ions was investigated. The calibration curve was linear in the range of 10–200 ng L −1of cadmium in the initial solution with r = 0.9992 ( n = 8) under optimum conditions. The limit of detection based on three times the standard deviation of the blank (3S b, n = 10) was 4.6 ng L −1. The relative standard deviation (R.S.D.) of 25 and 150 ng L −1 of cadmium was 4.1 and 2.2% ( n = 8), respectively. The procedure was validated by the analysis of a certified reference material (DORM-3), water and fish samples.

Synthesis and characterisation of sodium trititanate whisker surface Cd(II) ion-imprinted polymer and selective solid-phase extraction of cadmium

A new surface ion-imprinted polymer (IIP) was synthesised with sodium trititanate whisker in the presence of Cd(II), chitosan (CTS) and γ-glycidoxypropyl trimethoxysilane (KH-560). The prepared surface IIP was characterised by using FTIR, UV, XRD and SEM. A batch of adsorption experiments were performed to evaluate the adsorption behaviour of Cd(II) using inductively coupled plasma atomic emission spectrometry (ICP-AES). The effects of solution pH and sorbent amount on the extraction of Cd(II) from aqueous solutions were studied. The adsorption kinetics and adsorption isotherm were also obtained. The Langmuir isotherm can fit the experimental equilibrium data. Under the optimum conditions, the value of the adsorption was above 99%, and the maximum adsorption capacity was 52.34 mg/g. In accordance with the parameters distribution coefficient (Kd) and selectivity coefficient (K), the selectivity for Cd (II) of the prepared imprinted polymer was higher than non-imprinted polymer. Finally, the reuse of imprinted sorbent was discussed and showed that it could be reused nine times with about 5.0%-6.0% regeneration loss. The detection limit of 0.024 μg/mL−1 with the relative standard deviation (RSD) of 1.74% (C = 1.0 μg/mL−1, n = 13) of this method was obtained.