Ti(IV) ion-imprinted polymer as a new selective sorbent for extraction and pre-concentration of trace amounts of titanium ions in different samples

ABSTRACT

In this paper, a novel, simple, selective and effective solid phase extraction method based on ion-imprinted polymer (IIP) technology and flame atomic absorption spectrometry (FAAS) for separation and pre-concentration of trace amounts of titanium (IV) ions was reportd?. It was obtained by precipitation polymerisation by using 2-(2,4-dihydroxyphenyl)-3,5,7-trihydroxychromen-4-one titanium (IV) complex abbrivated as Ti(IV)-(morin), as the template molecule. After polymerisation, leaching the polymer in HNO₃ (50% (v/v) solution caused formation cavities in the polymer. Characterisation studies of the ?Ti(IV)-imprinted polymer (Ti-IP) was performed by FT-IR, UV-Vis and scanning electron microscopy-energy-dispersive X-ray spectroscopy (SEM-EDS) techniques and then, the effective factors on extraction were optimised. A sensitive response to Ti(IV) within a concentration range between 0.01 and 4.0 μg mL^?1 was achieved under the optimum conditions. A total of 10.0 ng mL^?1 and 80.0 mg g^?1 were obtained as limit of detection (LOD, 3Sb/m) and maximum adsorption capacity, respectively. The relative standard deviation (RSD) for eight replicates detections of 0.2 μg mL^?1 of Ti(IV)? was found to be 2.8%. By this method, pre-concentration factor (PF) of 100 was obtained. Successfully applying this method in the water and standard samples, reasonable results were obtained for the extraction and pre-concentration of the titanium ions.     

Novel ion-imprinted polymer coated on nanoporous silica as a highly selective sorbent for the extraction of ultratrace quantities of gold ions from mine stone samples

We have developed a gold ion-imprinted polymer (GIP) by incorporating a dipyridyl ligand into an ethylene glycol dimethacrylate matrix which then was coated onto porous silica particles. The material was used for the selective extraction of ultratrace quantities of gold ion from mine stones, this followed by its quantitation by FAAS. The effects of concentration and volume of eluent, pH of the solution, flow rates of sample and eluent, and effect of potentially interfering ions, especially palladium and platinum, was investigated. The limit of detection is <0.2 ng?mL^?1, the precision (RSD%) is 1.03 %, and recoveries are >99 %. In order to show the high selectivity and efficiency of the new sorbent, the results were compared to those obtained with more simple sorbents possessing the same functional groups. The accuracy of the method was demonstrated by the accurate determination of gold ions in a certified reference material. To the best of our knowledge, there is no report so far on an imprint for gold ions that has such a selectivity over Pd(II) and Pt(II) ions.

An ion-imprinted polymer based on attapulgite as a sacrificial support for selective separation of cerium(Ⅲ) ions from aqueous solution

Separation and enrichment technology of cerium(Ⅲ) ions (Ce~(3+)) has always been of interest,especially in the latest decades,because cerium(Ⅲ) has been widely used as micro-additives in functional materials,gasolene catalysts,polishing powder,ceramic and metallurgical areas.     

A novel ion-imprinted nanocomposite for selective separation of Pb2+ ions

In this study, the ion-imprinting method has been integrated to develop a novel composite material for the selective separation of Pb²⁺ ions. Also, Pb²⁺ ion binding ability of the organosmectite based inorganic-organic composite incorporation of bicyclic C18 organic compound into smectite layers was conducted to draw a projection its potential use as a solid phase exchanger which is quite selective toward Pb²⁺ ions. The ion-imprinted nanocomposites were characterized by Fourier transform infrared (FTIR), X-ray diffraction (XRD), swelling tests, and elemental analyses. After that, maximum binding capacity, pH, and equilibrium binding time were also been optimized. In order to show the selectivity of the composite synthesized, non-imprinted composites were also synthesized in absence of Pb²⁺ ions during polymerization. In this step, Ni²⁺, Co²⁺, Al³⁺, Zn²⁺, and Cu²⁺ ions were used as competitors under batch adsorption conditions. The relative selectivity coefficients of imprinted composite were calculated as 28.5, 156.5, 69.3, 24.8 and 131.6 for Pb²⁺/Co²⁺, Pb²⁺/Cu²⁺, Pb²⁺/Al³⁺, Pb²⁺/Zn²⁺, Pb²⁺/Ni²⁺ binary solutions, respectively. Finally, reusability of the composites was evaluated to show its cost-efficiency by repeating adsorption-desorption experiments ten-times. The adsorption capacity of the imprinted composites did not change significantly whereas that of non-imprinted version reduced dramatically.     

Functional crosslinked polymer particles synthesized by precipitation polymerization for liquid chromatography

Highly crosslinked functional polymer particles with narrow size distribution have been produced by precipitation copolymerization of divinylbenzene, ethylene glycol dimethacrylate and vinylbenzyl chloride using a simple reflux protocol. After establishing the satisfactory synthesis conditions, we produced uniform chlorobenzyl particles with different size depending on the polymerization times. The porosity of those particles was modulated from microporous to mesoporous structure by using various porogens such as toluene, dodecanol, cyclohexanol and polypropylene glycol. These particles were tested as stationary phase in high-performance liquid chromatography for the separation of polycyclic aromatic hydrocarbons in reversed-phase mode. The separation was observed even for elution 100% organic (methanol) without any participation of water fraction in the eluent composition. The influences of particles size, specific surface area and packing conditions on the separation behavior were investigated.     

Synthesis of magnetic nanoparticle‐based molecularly imprinted polymer as a selective sorbent for efficient extraction of ezetimibe from biological samples

In the present study, a novel and efficient adsorbent constructed of molecularly imprinted polymer on the surface of modified magnetic nanoparticles with oleic acid (MNPs) was applied for the selective extraction of ezetimibe. The magnetic molecularly imprinted polymer (MMIP) was polymerized at the surface of modified MNPs using methacrylic acid as functional monomer, ezetimibe as template and ethylene glycol dimethacrylate as cross‐linker. The resulting MMIP showed high adsorption capacity, good selectivity and fast kinetic binding for the template molecule. It was characterized by Fourier transform infrared analysis, scanning electron microscopy and transmission electron microscopy methods. The maximum adsorption capacity of MMIP was obtained as 137.1 mg g^?1 and it took about 20 min to achieve the equilibrium state. The adsorption model of the adsorbent was fitted with the Freundlich and Langmuir isotherm equations. The assay exhibited a linear range of 0.003–20.000 mg L^?1 for ezetimibe with a correlation coefficient of 0.995. The relative standard deviations for the recoveries were <5.2. The method was also examined for the analysis of ezetimibe in the biological samples.     

Synthesis of ion-imprinted mesoporous silica gel sorbent for selective adsorption of copper ions in aqueous media

A new Cu(II) ion-imprinted sorbent was synthesized by a surface imprinting technique and characterized by FT-IR and SEM. Compared to the non-imprinted sorbent, the Cu(II) ion-imprinted sorbent had a higher adsorption capacity and selectivity for Cu(II). The static adsorption capacity of the Cu(II) ion-imprinted sorbent and non-imprinted sorbent for Cu(II) were 84.5 and 46.5 μmol?g^?1, respectively. The best selectivity coefficient over Zn(II) or Cd(II) ion was over 12. The relative selectivity coefficients of the sorbent for Cu(II) in the presence of Zn(II) and Cd(II) were 13 and 35, respectively. Furthermore, the new sorbent possessed a fast kinetics for Cu(II) sorption from aqueous solution with saturation time of <30 min, and could be used repeatedly. The standard deviation for 11 replicate determinations of 0.5 mg?L^?1 Cu(II) was 0.8%. This new Cu(II) ion-imprinted sorbent can be used as an effective solid-phase extraction material for the selective preconcentration and separation of Cu(II).     

Application of a new nanoporous sorbent for extraction and pre-concentration of lead and copper ions

The authors describe a method for the trace determination of copper (II) and lead (II) in water and fish samples using solid-phase extraction via siliceous mesocellular foam functionalised by dithizone. Siliceous mesocellular was functionalised with dithizone, and the resulting sorbent was characterised by scanning electron microscopy, surface area analysis, thermogravimetric/differential thermal analysis and FTIR. Following solid-phase extraction of target ions by the sorbent, copper and lead ions were quantified by flame atomic absorption spectrometry. Factors affecting the sorption and desorption of target ions by the sorbent were evaluated and optimised. The calibration plot is linear in the 1 – 500 μg L^?1 copper (II) and 3–700 μg L^?1 lead (II) concentration range. The relative recovery efficiency in real sample analysis is in the range from 96 to 102%, and precision varies between 1.7 and 2.8%. It is should be noted that the limits of detection for the copper and lead analysis were 0.8 and 1.6 μg L^?1, respectively. Also, the adsorption capacities for copper and lead ions were 120 and 160 mg g^?1, respectively. The obtained pre-concentration factor for the lead and copper ions by the proposed solid-phase extraction was 75. The method was successfully applied to the determination of low levels of copper (II) and lead (II) in tap, Caspian sea, Persian gulf and lake water and also their detection in fish samples.     

Bifunctional aminosilane-functionalized Fe3O4 nanoparticles as efficient sorbent for preconcentration of cobalt ions from food and water samples

Research on Chemical Intermediates - Magnetic Fe3O4 nanoparticles were synthesized by a coprecipitation method, then their surface was covered and modified by...     

A nanostructured ion-imprinted polymer for the selective extraction and preconcentration of ultra-trace quantities of nickel ions

We describe a nanostructured ion-imprinted polymer (IIP) for the selective preconcentration of Ni(II) ions. It was obtained by bulk polymerization from 2-vinylpyridine (the functional monomer), ethylene glycol dimethacrylate (the cross-linker), 2,2′-azobisisobutyronitrile (the initiator), alizarin red S (the nickel-binding ligand), and nickel (the template ion) in acetonitrile solution. The IIP particles were characterized by elemental analysis, X-ray diffraction, Fourier transform IR spectroscopy, thermogravimetric and differential thermal analysis, and by scanning electron microscopy. Imprinted Ni(II) ions were removed from the polymeric structure using 5 % HCl as the eluting solvent. The material is capable of selectively binding Ni(II) from solutions at pH values between (pH 8.0 being best). Both the sorption and desorption process occur within 5 min. The maximum sorbent capacity of the ion imprinted polymer is 73 mg g^?1. Following desorption, Ni(II) was determined by FAAS, with relative standard deviation and limit of detection of 3.4 % and 0.15 ng mL^?1, respectively. The method was applied to the determination of nickel in certified reference materials (soil and polymetallic gold ore), fish, vegetables, river sediments, and river water.

Application of a new ion-imprinted polymer for solid-phase extraction of bismuth from various samples and its determination by ETAAS

A batch process was developed to extract bismuth ions by a novel and selective sorbent. In this study, a new Bi(III)-ion imprinted polymer was prepared by formation of 2-(5-bromo-2-pyridylazo)-5-diethylaminophenol complex for selective preconcentration of ultra trace amounts of bismuth. Polymerization was performed with ethylene glycol dimethacrylate, as crosslinking monomer and methacrylic acid as functional monomer; in the presence of 2,2-azobisisobutyronitrile, as initiator, via bulk polymerization. Optimum pH for maximum sorption was 2.5–3.5. Maximum sorbent capacity and enrichment factor for bismuth were 35.9?mg?g^?1 and 300, respectively. The relative standard deviation and limit of detection the method were evaluated as ±4.1% and 8.6?ng?L^?1. This method is simple, selective and sensitive and can be applied to the determination of bismuth in water, biological and plant samples.     

Synthesis of an ion-imprinted sorbent by surface imprinting of magnetized carbon nanotubes for determination of trace amounts of cadmium ions

Microchimica Acta - The authors report on the preparation of sol-gel coated magnetized carbon nanotubes whose surface were imprinted with Cd2+ ions and the application of these materials on...     

Application of the ion-exchanger Cellex P for the selective separation of some metal ions

Summary The selectivity of the cellulose ion-exchanger Cellex P containing phosphonic groups has been examined by means of tetrene. The affinity of 14 metal ions was determined as a function of the pH-value in the presence of tetrene. Bismuth was separated from large excess of Pb, Cd, Cu, Co, Ni, Fe, Mn and Zn by means of this ion-exchanger using tetrene as a complexing agent. The method has been applied to the determination of bismuth in metallic lead.

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Anwendung des Ionenaustauschers Cellex P zur selektiven Abtrennung einiger MetallionenTeil 3. Quantitative Abtrennung des Bismuts von anderen Elementen in Gegenwart von Tetraethylenpentamin (Tetren) als Komplexierungsmittel

Zusammenfassung Die Selektivität des Phosphonsäuregruppen-haltigen Celluloseaustauschers Cellex P wurde mit Hilfe von Tetren untersucht. Die Affinität von 14 Metallionen wurde als Funktion des pH-Wertes in Gegenwart von Tetren bestimmt. Bismut konnte von einem großen Überschuß an Pb, Cd, Cu, Co, Ni, Fe, Mn und Zn abgetrennt werden. Das Verfahren wurde zur Bismutbestimmung in Bleimetall angewendet.

     

Application of magnetic graphene-based bucky gel as an efficient green sorbent for determination of mercury in fish and water samples

Research on Chemical Intermediates - In this article, a highly efficient method based on coupling magnetic solid-phase extraction and dispersive microsolid-phase extraction was proposed to...     

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

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

Continuous separation of copper ions from a mixture of heavy metal ions using a three-zone carousel process packed with metal ion-imprinted polymer

In this study, a three-zone carousel process based on a proper molecular imprinted polymer (MIP) resin was developed for continuous separation of Cu(2+) from Mn(2+) and Co(2+). For this task, the Cu (II)-imprinted polymer (Cu-MIP) resin was synthesized first and used to pack the chromatographic columns of a three-zone carousel process. Prior to the experiment of the carousel process based on the Cu-MIP resin (MIP-carousel process), a series of single-column experiments were performed to estimate the intrinsic parameters of the three heavy metal ions and to find out the appropriate conditions of regeneration and re-equilibration. The results from these single-column experiments and the additional computer simulations were then used for determination of the operating parameters of the MIP-carousel process under consideration. Based on the determined operating parameters, the MIP-carousel experiments were carried out. It was confirmed from the experimental results that the proposed MIP-carousel process was markedly effective in separating Cu(2+) from Mn(2+) and Co(2+) in a continuous mode with high purity and a relatively small loss. Thus, the MIP-carousel process developed in this study deserves sufficient attention in materials processing industries or metal-related industries, where the selective separation of heavy metal ions with the same charge has been a major concern.     

A highly selective solid phase extraction sorbent for pre-concentration of sameridine made by molecular imprinting

Summary A novel approach to solid phase extraction, based on the use of a highly selective molecularly imprinted polymer, is presented. The versatility of this type of sorbent for solid phase extraction was demonstrated in a model batch-wise pre-concentration of sameridine prior to gas chromatography. Problems associated with leakage of remaining imprint molecules during the desorption phase could be eliminated by the use of a close structural analogue of sameridine as the imprint species. It was found that a major benefit of the imprinted polymer was its specificity, which lead to distinctly cleaner chromatographic traces and ability to improve sensitivity by extracting sameridine from larger sample volumes.