Liquid Anion Exchanger Research Articles

Research of saccharides and related biocomplexes: A review with recent techniques and applications.

Saccharides and biocompounds as saccharide (sugar) complexes have various roles and biological functions in living organisms due to modifications via nucleophilic substitution, polymerization, and complex formation reactions. Mostly, mono-, di-, oligo-, and polysaccharides are stabilized to inactive glycosides, which are formed in metabolic pathways. Natural saccharides are important in food and environmental monitoring. Glycosides with various functionalities are significant in clinical and medical research. Saccharides are often studied with the chromatographic methods of hydrophilic interaction liquid chromatography and anion exchange chromatograpy, but also with capillary electrophoresis and mass spectrometry with their on-line coupling systems. Sample preparation is important in the identification of saccharide compounds. The cases discussed here focus on bioscience, clinical, and food applications.

Chromatographic Fractionation of Penicillium polonicum Fermentation Metabolites in Search of the Nephrotoxin(s) for Rats.

Complex renal histopathological changes in rats, in silent response to dietary contamination with wheat moulded by a common Penicillium from the Balkans, have long eluded attribution of a causal toxin. So far, water-soluble amphoteric glyco-peptides seem responsible, at least for the nuclear pyknoses in nephron epithelia after several days of dietary exposure. Recently, refined histology analysis has diagnosed pyknosis as apoptosis, and followed the finding through application of medium-pressure liquid chromatography, anion exchange and silica layer chromatography to fractionate a water/alcohol-soluble extract of a fungal fermentation on wheat. Proline was revealed, with other amino acids, in acid hydrolysate of the fermentation extract. Application of mass spectrometry has recognized prominent ions (m/z 550 and 564) correlated with fragmentations consistent with a terminal proline moiety for the putative toxins, coupled with other structural fragments and correlated with apoptosis. Use of 14C-proline in probing Penicillium polonicum fermentation to aid isolation of the new potential toxins, along with application of gel electrophoresis, may further aid characterization of the apoptosis toxin(s). The present focus on proline peptides in mycotoxicosis fits easily with their increasingly recognised pharmacological activity associated with proline’s rigid secondary amine structure, which causes conformational contortion in peptides. Nevertheless, there remains the striking rat renal karyocytomegaly by P. polonicum, for which there is yet no causative mycotoxin.

Development and validation of the HPLC-DAD method for the quantification of 16 synthetic dyes in various foods and the use of liquid anion exchange extraction for qualitative expression determination

Synthetic dyes can cause many health problems, and their use as food additives is rigorously regulated worldwide. Two methods for the determination of synthetic dyes in food are described in this article. The visual qualitative expression method was based on the extraction of synthetic dyes using a liquid anion exchanger (0.01 M solution of trioctylmethylammonium chloride in chloroform). Using this reagent, an optimal transition of 15 anionic synthetic dyes from the aqueous to the organic phase was achieved (R > 99.8%). It was applicable for testing food that must not contain synthetic dyes (wines, juices, etc.) in a very short time (5–10 min). In the case of colouring of the organic phase, identification and quantification was carried out using the HPLC-DAD method described. The rapid and simple method allows for simultaneous determination of 16 synthetic dyes from all food types. The LOD and LOQ ranged from 0.026 to 0.086 μg mL−1 and from 0.077 to 0.262 μg mL−1 respectively, and recovery was 83.7–107.5%.Hypothesis: anionic synthetic dyes have hydrophobic properties, as a result they are retained on the non-polar stationary phase of the chromatographic column and are easily extracted from aqueous solutions by liquid anion exchangers.

Preparation and evaluation a mixed-mode stationary phase with C18 and 2-methylindole for HPLC.

A modified C18 column (Silpr-2MI-C18) was prepared using 2-methylindole and C18 reagent. The extent of C18 hydrocarbon chain, conjugative rings and anion exchange site provided multiple retention mechanisms, including reversed-phase liquid chromatography (RPLC), π-π interaction, hydrophilic interaction liquid chromatography (HILIC) and anion exchange chromatography (AEC). The separation of protected amino acids was investigated on the commercial C18 and Silpr-2MI-C18 columns, while the chromatographic conditions, including methanol content and pH of the mobile phase, were studied. The separation arrangement of the hydrophilic amino acids was different on the Silpr-2MI-C18 column compared to the commercial C18 column under RPLC mode. Furthermore, these amino acids were separated on the Silpr-2MI-C18 column under HILIC mode. The modified C18 column was employed to separate amino acids, alkylbenzenes and polycyclic aromatic hydrocarbons under RPLC mode and inorganic anion under AEC mode. The results confirm that this new stationary phase of RPLC/HILIC/AEC has multiple interactions with different analytes. Effective retention of biological samples was found on the Silpr-2MI-C18 column by comparing the results obtained from the commercial C18 column.

Mg-Al-CO3 layered double hydroxide reinforced polymer inclusion membrane as an extractant phase for thin-film microextraction of cyanide from environmental water samples.

In this paper, a flexible and efficient nano-reinforced polymer inclusion membrane (PIM) was fabricated and used for cyanide (CN-) extraction from water samples. Aliquat 336 (a liquid anion exchanger) was embedded in poly(vinyl chloride) (PVC) support as the extractant. Mg-Al-CO3 layered double hydroxide (LDH) with high surface area and anion exchange ability was applied to promote the extraction efficiency of PIM. A PIM comprising 56% PVC, 40% Aliquat 336, and 4% Mg-Al-CO3 LDH showed the best extraction efficiency. A single beam ultraviolet-visible spectrophotometer was used for the detection of cyanide. Surface morphology of the PIM was studied by field emission scanning electron microscopy. The experimental parameters influencing the extraction process were investigated and optimized. The intra- and inter-day relative standard deviations at two different concentrations were in the range of 2.8-7.6%. The dynamic range of the method was in the range of 5-500μgL-1, and the detection limit was 1.4μgL-1. The LDH reinforced PIM showed proper characteristics for the extraction of cyanide from real water and wastewater samples with recoveries between 82 and 115%.

Unfolding the complexation and extraction of Am3+ and Eu3+ using N-heterocyclic aromatic diphosphonic acids: a combined experimental and DFT study.

Phosphonate based ligands are well known for the extraction of 'f' block elements. Three N,O-donor N-heterocyclic aromatic diphosphonate ligands were evaluated in the present work for the extraction/separation studies of Am3+ and Eu3+. Complexation studies in aqueous medium using luminescence titration indicated the formation of anionic complexes in the case of Eu3+. Two phase liquid-liquid extraction studies were, therefore, carried out by employing Aliquat-336 as the liquid anion exchanger. The results indicated the formation of a species with a metal-ligand stoichiometry of 1 : 3 in the case of pyridine-2,6-diphosphonic acid (PyPOH). In the case of 2,2'-bipyridine-6,6'-diphosphonic acid (BipyPOH), however, a 1 : 2 complex was extracted and 1,10-phenanthroline-2,9-diphosphonic acid (PhenPOH) extracts the Am3+ and Eu3+ ions by forming both 1 : 2 and 1 : 3 complexes. Formation of these kinds of anionic complexes was further confirmed using electrospray ionization mass spectrometry (ESI-MS). DFT calculations predicted the structure of the anionic complexes. The non-selectivity of these kinds of ligands between Am3+ and Eu3+ was attributed to the presence of unfavorable covalent interactions in the metal-ligand bonds.

Dispersive liquid–liquid microextraction based on liquid anion exchanger for the direct extraction of inorganic anions

For the first time, the possibility of the use of liquid anion exchangers in dispersive liquid–liquid microextraction for the direct extraction of some inorganic anions (nitrite, nitrate, and iodide) was evaluated. In this technique, chloroform containing a liquid anion exchanger (trioctylamine) was used as extractant. The mixture of the extractant and disperser solvent (acetonitrile) was injected into the acidic sample solution. The protonated trioctylamine formed a water-insoluble salt with the inorganic anions (analytes). After the phase separation and stripping of the analytes from the extractant, the analytes were determined by liquid chromatography with UV detection. Various parameters affecting the extraction efficiency were investigated. Under the optimum conditions, broad linear dynamic ranges, with determination coefficients (r2) higher than 0.998, and enrichment factors between 94 and 244 were obtained. The limits of detection and quantification were in the range of 0.1–0.5 and 0.4–1.7 μg L−1, respectively. Also, the values of intra- and inter-day relative standard deviations were 3.5–5.8% and 5.5–7.8%, respectively. Various real water samples including sea, tap, river, spring and mineral water were analyzed by the method. The method was sensitive, simple, inexpensive and capable of the simultaneous extraction and determination of the selected inorganic anions.

Separation of neptunium (IV) from actinides by solid phase extraction using a resin containing Aliquat 336

An extraction chromatographic resin material containing Aliquat 336 as the liquid anion exchanger extractant and Chromosorb W as the solid support was prepared and tested for the uptake of UO22+, Np4+, Pu4+, and Pu3+ from nitric acid feed solutions. The resin beads were characterized by thermogravimetry/differential thermogravimetry (TG/DTG) and scanning electron microscopy (SEM) surface morphology analysis. The uptake trend for the metal ions from 3 M HNO3 was found to be Pu4+ >> Np4+ >> UO22+ > Pu3+ which clearly followed the trend of their ionic potentials. In view of the significant difference in the uptake of Np4+ with respect to those of UO22+ and Pu3+, a separation scheme was developed for the selective separation of Np from feeds containing U, Np and Pu in nitric acid. The purity of the product was verified by alpha spectrometry.

4-Methyl-N-n-Octylaniline as a New Liquid Anion Exchanger for the LiquidLiquid Extraction of Gallium (III): Application to Electronic Waste LED

4-Methyl-N-n-Octylaniline as a New Liquid Anion Exchanger for the LiquidLiquid Extraction of Gallium (III): Application to Electronic Waste LED

Reversed Phase Extraction Chromatographic Separation of Platinum (IV) with High Molecular Mass Liquid Anion Exchanger on Silica gel

Reversed Phase Extraction Chromatographic Separation of Platinum (IV) with High Molecular Mass Liquid Anion Exchanger on Silica gel

Liquid Anion Exchange Chromatographic Extraction and Separation of Osmium(VIII) with 4-(4-Methoxy-benzylideneimino)-5-methyl-4H-1,2,4-triazole-3-thiol in Hydrochloric Acid Medium

A novel method is proposed for the extraction of microgram level concentration of osmium(VIII) from hydrochloric acid medium with 4-(4-methoxybenzylideneimino)-5-methyl-4H- 1,2,4-triazole-3-thiol (MBIMTT) dissolved in chloroform as an extractant. The osmium(VIII) from the organic phase is stripped with mixture of thiourea and 2 M hydrochloric acid and determined spectrophotometric method. The method affords the binary separation and determination of osmium(VIII) from synthetic mixture. The method is successfully applied for the separation and determination of osmium from the alloys. The method is highly selective, simple and reproducible.

Liquid–liquid microflow patterns and mass transfer of radionuclides in the systems Eu(III)/HNO3/DMDBTDMA and U(VI)/HCl/Aliquat® 336

Two phases (liquid–liquid extraction) stratified flows in a rectangular geometry are investigated in a double-Y shape glass chip. The influence of physical properties, in particular the viscosity of the two liquids, on the velocity profiles is determined numerically. Viscosity affects the shapes of the velocity profiles of each phase. The extraction conditions (acid concentrations, contact times) in batch and in the microfluidic device were considered for a neutral extractant, N,N′-dimethyl N,N′-dibutyl tetradecylmalonamide (DMDBTDMA) and a liquid anion exchanger (Aliquat® 336), for the extraction of Eu(III) from HNO3 and U(VI) from HCl, respectively. The effects of viscosity and operating conditions on extraction performances were investigated, and the apparent rate constants were evaluated for the extraction of uranium by Aliquat® 336 k app = (0.55 ± 0.03) s−1 and for the extraction of europium by DMDBTDMA: k app = (2.9 ± 0.2) × 10−3 s−1.

Extraction chromatography of aluminium(III) and mutual separation of aluminium(III) , gallium(III) , indium(III) and thallium(III) with <I>N</I>-<I>n</I>-octylaniline

A selective method has been developed for the extraction chromatography of aluminium (III) and its separation from several metal ions with a chromatographic column containing N-n-octylaniline (a liquid anion exchanger) coated on silanized silica gel as a stationary phase. The aluminium (III) was quantitatively extracted with the 0.065 mol/L N-n-octylaniline in 0.013 to 0.05 mol/L sodium succinate at a flow rate of 1.0 mL/min. The extracted metal ion has been recovered by eluting with 25.0 mL of 0.05 mol/L hydrochloric acid and estimated spectrophotometrically with aurintricarboxylic acid. The effects of the acid concentration, the reagent concentration, the flow rate and the eluting agents have been investigated. The log-log plots of distribution coefficient (Kd (Al (III))) versus N-n-octylaniline concentration in 0. 005 and 0. 007 mol/L sodium succinate gave the slopes of 0.5 and 0.7 respectively and showed the probable composition of the extracted species was 1:1 (metal to amine ratio) and the nature of extracted species was [RR'NH2(+), Al succinate2(-)]org. The extraction of aluminium(III) was carried out in the presence of various ions to ascertain the tolerance limit of individual ions. Aluminium(III) has been separated from multicomponent mixtures, pharmaceutical samples and synthetic mixtures corresponding to alloys. A scheme for mutual separation of aluminium (III), indium (III), gallium (III) and thallium (III) has been developed by using suitable masking agents. The method is fast, accurate and precise.

Production and separation of 97Ru and coproduced 95Tc from 12C-induced reaction on yttrium target

Abstract An attempt has been made to produce no-carrier-added (nca) 97Ru for the first time from the 12C-induced reaction on yttrium target. A natY foil of 10 mg/cm2 thickness was irradiated by 75 MeV 12C beams for 3.5 h and a thick target yield of 514 kBq/μA h for 97Ru and 338 kBq/μA h for 95Tc was achieved. The nca 97Ru and coproduced nca 95Tc were then radiochemically separated from the bulk target by liquid–liquid extraction (LLX). Liquid cation exchanger di-(2-ethylhexyl)phosphoric acid (HDEHP), liquid anion exchanger trioctylamine (TOA) were used in this study. The technique offers efficient chemical separation of the products, resulting in very high separation factors.

Liquid Anion Exchange Chromatographic Extraction and Separation of Platinum(IV) with n‐Octylaniline as a Metallurgical Reagent: Analysis of Real Samples

A simple and selective method was developed for the determination of platinum(IV) with n‐octylaniline in toluene. In present study, the use of n‐octylaniline in toluene for the extraction of platinum(IV) from ascorbate media was carried out. The effect of various parameters, such as pH, equilibrium time, extractant concentration, and organic solvent on the extraction has been discussed. The back extraction of platinum(IV) has been performed. On the basis of slope analysis, the composition of the extracted species was determined as [RR′NH2+ Pt(Succinate)2−](org). The interfering effects of various cations and anions were also studied, and the selectivity of the method is enhanced by using suitable masking agents. The proposed method is rapid, reproducible and successfully applied for the determination of platinum(IV) in binary and synthetic mixtures. The separation of pt(IV) from other associated metals has been studied. Comparison of the results with those obtained using an atomic absorption spectrophotometer also tested the validity of the method.

Liquid Anion Exchange Chromatographic Extraction and Separation of Platinum (IV) with N-Octylaniline as an Metallurgical Reagent: Analysis of Real Samples

A simple and selective method was developed for the determination of platinum (IV) with n-octylaniline in toluene. In present study, the use of n-octylaniline in toluene for the extraction of platinum (IV) from ascorbate media was carried out. The effect of various parameters, such as pH, equilibrium time, extractant concentration and organic solvent on the extraction has been discussed. The back extraction of has been performed. On the basis of slope analysis, the composition of the extracted species was determined as [RR’NH2 + Pt (Succinate)2 -](org). The interfering effects of various cations and anions were also studied, and use of suitable masking agents enhances the selectivity of the method. The proposed method is rapid, reproducible and successfully applied for the determination of platinum (IV) in binary and synthetic mixtures. The separation of platinum (IV) from other associated metals has been studied. Comparison of the results with those obtained using an atomic absorption spectrophotometer were also tested the validity of the method.

Deacidification of crude low-calorie cocoa butter with liquid–liquid extraction and strong-base anion exchange resin

A feasible and novel deacidification process for the production of refined low-calorie cocoa butter by liquid–liquid extraction and anion exchange resin was investigated. The results showed that ethanol was a better solvent for extraction than methanol and isopropanol. The commercially available anion exchange resin D202 used in the experiments had a maximum adsorption capacity of 223.71mg/g. With a two-stage extraction using 85vol.% aqueous ethanol and an interaction time with resin of 4h under the optimum conditions, low-calorie cocoa butter with an acid value of 0.81mgKOH/g was obtained. Stable and qualified final products were acquired from 10 batches, indicating that the integrated process had no significant tendency to change the characteristics of low-calorie cocoa butter. The D202 anion exchange resin was regenerated and reused in 38 consecutive batches.

Selectivity Control in Synergistic Liquid–Liquid Anion Exchange of Univalent Anions via Structure-Specific Cooperativity between Quaternary Ammonium Cations and Anion Receptors

Two anion receptors enhance liquid-liquid anion exchange when added to quaternary alkylammonium chloride anion exchangers, but with a striking dependence on the structure of the alkylammonium cation that suggests a supramolecular cooperative effect. Two anion receptors were investigated, meso-octamethylcalix[4]pyrrole (C4P) and the bisthiourea tweezer 1,1'-(propane-1,3-diyl)bis(3-(4-sec-butylphenyl)thiourea (BTU). Whereas synergism is comparatively weak when either methyltri(C(8,10))alkylammonium chloride (Aliquat 336) or tetraheptylammonium chloride is used with the BTU receptor, synergism between C4P and Aliquat 336 is so pronounced that anion exchange prefers chloride over more extractable nitrate and trifluoroacetate, effectively overcoming the ubiquitous Hofmeister bias. A thermochemical analysis of synergistic anion exchange has been provided for the first time, resulting in the estimation of binding constants for C4P with the ion pairs of A336(+) with Cl(-), Br(-), OAc(F3)(-), NO(3)(-), and I(-).

Production and separation of no-carrier-added thallium isotopes from proton irradiated natHg 2Cl 2 matrix

For the first time, natHg 2Cl 2 target has been used to produce no-carrier-added—NCA 197,198,198m,199,200,201Tl radionuclides using natHg(p,xn) reaction. Liquid–liquid extraction technique was employed in order to separate radiothallium from the bulk mercury matrix using liquid anion exchanger trioctylamine (TOA) dissolved in cyclohexane. In order to verify the presence of stable Hg in Tl fraction, the entire process was repeated with stable salts of Hg and Tl and the extent of separation was examined by Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES). High separation factors were observed both by radiometric and ICP-OES technique when 0.1 M HNO 3 and 0.1 M TOA were used as aqueous and organic phase, respectively. The Hg contamination was less than 0.3 ppm in the aqueous phase containing Tl after three times of extraction at the optimal condition.

Electrochemical studies of U(VI)/U(V) in saturated Na2CO3solution at gold nanoparticles embedded CTA-modified electrode

AbstractGold nanoparticles (AuNPs) were prepared in the matrix of cellulose triacetate (CTA) membrane containing a liquid anion exchanger trioctylmethylammonium chloride (Aliquat-336). The AuCl4−ions were transferred in the membrane matrix by anion-exchange process, and then subsequently reduced with NaBH4to form AuNPs in the membrane. The AuNPs-embedded CTA (AuNPs-CTA) membrane was characterized by UV-visible spectroscopy, XRD and AFM. The electrochemical properties of AuNPs-CTA modified electrode were evaluated by studying redox behavior of UO22+/UO2+couple in saturated Na2CO3solution, using voltammetric techniques. In carbonate solution, the predominant species of UO22+is [UO2(CO3)3]4−, and a stable UO2(CO3)35−complex is formed by one-electron reduction of UO2(CO3)34−. Previous reports show that the UO22+/UO2+couple, which is electrochemically reversible in less complexing media, becomes electrochemically irreversible in aqueous CO32−solution. In this study, an electrocatalytic reduction of UO22+to UO2+in saturated Na2CO3solution was observed at AuNPs-CTA-modified electrode with higher current density and faster heterogeneous electron-transfer kinetics than that at bare Au electrode. The standard heterogeneous rate constant,kº, for the reduction process at AuNPs-CTA modified electrode was about 25 times higher than that of bare Au electrode. Therefore, it is concluded that AuNPs-CTA membrane has improved the interfacial electron-transfer properties of electrode, resulting in a better electrochemical response than bare Au electrode.