Ion Exchange Extraction Research Articles

SOLID PHASE EXTRACTION (SPE) FOR MULTI-RESIDUE ANALYSIS OF β2-AGONISTS IN BOVINE URINE

Solid phase extraction (SPE) for the treatment of bovine urine samples in the analysis of β2-agonist multi-residues by gas chromatography-mass spectrometry (GC-MS) was evaluated. Mabuterol, mapenterol, clenproperol, terbutaline, clenbuterol, salbutamol, clenpenterol, bromobuterol and hidroxi-metilclenbuterol (NA1141) were tested with five different mechanisms: adsorption, reverse phase, polar, ion exchange, and mixed phase, and eleven sorbents: diatomaceous earth, octadecyl (C18), octyl (C8), native silica (Si), diol (2OH), amine (NH2), trimethylaminopropyl (SAX), propylbenzenesulphonic (SCX), Bond Elut Certify® (C8+SCX), Clean Screen DAU® (CSDAU) and Multimode (C18+SCX+SAX). Recoveries of the nine β2-agonists from urine samples spiked at 20 ng mL−1 using metoprolol as internal standard were in ranges of 2.9% to 58.1%, of 12.0% to 60.7%, of 6.3% to 31.3%, of 3.3% to 56.8% and of 17.7% to 66.9%, respectively for adsorption, non polar, polar, ion exchange, and multiple extraction mechanisms. The coefficients of variation (C.V.) were also evaluated and discussed. The proposed study show that mixed phase sorbents, especially those which combine hydrophobic and strong cationic exchange interactions, were recommended for a β2-agonist multi-residue solid phase extraction procedure from bovine urine.

Ion-exchange extraction of organic acids in water samples. Study of the influential factors and interactions

The objective is to concentrate organic acid traces in water samples. The influence of several parameters and their interactions on the adsorption of organic acids on anion exchange resins was studied. A complete factorial design 2 4 was hence performed. The measured response corresponds to the maximal percolation volume and the studied parameters were the nature and the mass of the resin, the percolation flow-rate and the ionic strength of the analysed water. The results shown that the pe r- colation flow-rate is significant but not really important compared to the resin mass and to the nature of water. Indeed, the sa mple inorganic anions can compete with organic acids. This adsorption competition appears to be more important when a macropo- rous resin is used. A gel-type resin could be therefore better adapted to the extraction of organic acids in water samples.

Palladium (II) complexes of hybrid phosphine—phosphine oxide ligands

Complexes of the type [L2PdCl2] , where L = Ph2PCH2P (O) Ph2 (dppmO) , Ph2P (CH2) 2P (O) Ph2 (dppeO) , Ph2P (CH2) 3P (O) Ph2 (dpppO) , Ph2P (CH2) 4P (O) Ph2 (dppbO) , and Ph2PC5H4FeC5H4P (O) Ph2 (dppfcO) , were prepared in high yield from Na2 [PdCl4] and 2 equiv. of the corresponding L in dichloromethane-methanol. All complexes, except for [ (dppfcO) 2PdCl2] , can exist as the cis and trans isomers, or mixtures of both, with the cis⧹trans ratio decreasing in media of low polarity. The ferrocene containing complex, [ (dppfcO) 2PdCl2] , appeared to be exclusively trans in both the solid state and solution, as established by single crystal X-ray diffraction of its 1 : 3 benzene solvate. The ion exchange extraction of dichloromethane solutions of [ (dppmO) 2PdCl2] and [ (dppeO) 2PdCl2] with aqueous NaBF4 furnished the corresponding cationic P,O-chelates, cis- [ (dppmO) 2Pd] 2 (BF−4)2 and cis- [ (dppeO) 2Pd] 2 (BF−4)2. Alternatively, these cations can be generated by the reaction between the chloro complexes, [ (dppmO) 2PdCl2] and [ (dppeO) 2PdCl2] , with Ag+. Single crystal X-ray diffraction of cis- [ (dppeO) 2Pd] 2 (BF−4)2 revealed distinct conformations (a puckered chair and a distorted sofa) for the two chelate rings situated around each Pd atom. A polymeric, poorly soluble material, { [ (dpppO) 2Pd] 2 (BF−4)2}n, was isolated from the reaction between [ (dppO) 2PdCl2] and AgNO3⧹ NaBF4, with both coordinated and free phosphoryl groups being present in the product (IR) . In dilute solutions of the { [ (dpppO) 2Pd] 2 (BF−4)2}n, depolymerization occurred, giving rise to the monomeric cationic chelate, cis- [ (dpppO) 2Pd] 2(BF−4)2.

Extraction of 7-Aminocephalosporanic Acid with Secondary, Tertiary, and Quaternary Amines

Extraction of 7-aminocephalosporanic acid (7-ACA) has been investigated using secondary and tertiary amines and a quaternary ammonium salt (Aliquat-336) as the carriers. The values of the distribution coefficients have been reported in a range of aqueous-phase pH values and concentrations of 7-ACA using different carriers in n-butyl acetate as the diluent. As expected, ion-pair extraction with secondary and tertiary amines exhibits lowerings of the distribution coefficient with increase of pH, whereas the ion exchange extraction with quaternary ammonium chloride (Aliquat-366) exhibits an opposite but more pronounced pH dependence, providing at the same time higher values of distribution coefficient at high values of pH. Both the extraction principles can be exploited to achieve extraction and reextraction of 7-ACA in the pH range of 5 to 8 in which it is relatively stable.

Preparation and characterization of234U for mass spectrometry and alpha-spectrometry

234U of high isotopic purity (>99 atom%) as well as of high radiochemical, purity was separated from aged238Pu prepared by neutron irradiation of237Np. Methodologies based on ion exchange and solvent extraction procedures were used to achieve high decontamination factor from238Pu owing to the very high α-specific activity of238Pu (2800 times) in comparison to that of234U. Isotopic composition of purified234U was determined by thermal ionisation mass spectrometry. Alpha spectrometry was used for checking the radiochemical purity of234U with respect to concomitant α-emitting nuclides. The separated234U will be useful for different investigations using mass spectrometry and alpha spectrometry.

Postcolumn Immunodetection Following Conditioning of the HPLC Mobile Phase by On-Line Ion-Exchange Extraction

Postcolumn immunodetection can provide enhancement of selectivity and sensitivity when used in combination with HPLC. Typical reversed-phase HPLC employs a variety of organic modifiers and buffers, and immunoassays generally perform best in a low ionic strength aqueous matrix with a pH between 7 and 8. There is therefore a need for removal of an analyte from a typical mobile phase into an environment compatible with an immunoreactor. An on-line system utilizing an ion-exchange column along with a switching valve to sequester an analyte from a HPLC mobile phase and apply a counterion eluent solution was designed to provide the proper matrix for immunoassay. An on-line HPLC−ion-exchange system was developed for the model analyte procainamide hydrochloride. The eluents from the on-line HPLC and ion-exchange system were collected and analyzed off-line using fluorescence polarization immunoassay. The fluorescence polarization immunoassay was calibrated using standards in a buffer matrix, and the system was validated using controls at 2.0, 7.0, and 15.0 μg/mL in mobile phase. Procainamide and its metabolite were extracted from spiked plasma using liquid−liquid extraction, and validation of the system with plasma samples demonstrated 15.60, 15.63 and 15.70% (n = 6) RSD for the three controls and accuracies of 6.42, 10.30, and 17.70% (n = 6) difference from spiked, respectively.

Preconcentration of Aliphatic Amines from Water Determined by Capillary Electrophoresis with Indirect UV Detection

Preconcentration methodology based on adsorption chromatographies for enriching aliphatic amines (CI to C4 substituted primary, secondary, and tertiary) and alkanolamines in water was studied by free zone capillary electrophoresis (CZE) with indirect UV detection. The solid-phase extraction of amines from water (pH 5) as a preconcentration step was studied for ion exchange solid-phase extraction (SCX) cartridges, cation ion exchange extraction disks, and ion-pairing with C18 extraction disks. In the course of the investigations, the electrophoretic properties of the amines was studied in some detail in order to optimize separations and detection limits. The indirect mode is particularly powerful in being able to detect primary through quarternary amines without derivatization. Mobilities of amines were correlated with their Stokes′ radii. Increased selectivity for resolving closely related amines under CZE was explored using nonionic surfactants, pH adjustment, and optimized background electroyle. Techniques were developed for obtaining stable baselines in the indirect detection mode. Linearity, sensitivity and efficiency were explored for this mode of detection for a large set of amines.

Determination of Heterocyclic Aromatic Amines in Process Flavors by a Modified Liquid Chromatographic Method

Abstract A liquid chromatographic method for determining heterocyclic aromatic amines (HAAs) was modified so that it can be used to quantitate the following 5 HAAs in complex process flavors: 2-amino-3-methylimidazo[4,5-f]quinoline (IQ); 2-amino-3,4-dimethylimidazo[4,5-f]quinoline (MelQ); 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MelQx); 2-amino-3,4,8-trimethylimidazo[4,5-f]quinoxaline (diMelQx); and 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP). By changing the initial extraction procedure, PhIP recovery improved from 35 to 87%. An additional cleanup step using ion-exchange solid-phase extraction reduced the levels of interfering components, thus allowing determination of low levels of the amines. Recoveries from process flavors spiked at 25 ppb averaged 83–90%.

Cell origin and paracrine control of interstitial collagenase in the guinea pig uterine cervix--evidence for a low molecular weight epithelial cell-derived collagenase stimulator.

Dilatation of the uterine cervix at parturition is achieved by degradation of type I collagen, the main structural protein in the cervix, by interstitial collagenase. In order to determine the cell origin of interstitial collagenase in the cervix, separate stromal and epithelial cell cultures were established. Using a highly sensitive and specific assay for collagenase that utilizes [3H]telopeptide-free type I collagen as a substrate, we determined that the cells of origin of collagenase were cervical stromal cells and not cervical epithelial cells. Cells of cervical epithelium produced factors in culture that stimulated stromal cell collagenase production. The addition of epithelial cells or epithelial cell-conditioned culture medium to stromal cells resulted in a dose-dependent stimulation of stromal cell collagenase production with a maximum increase of 3- or 6-fold, respectively. To characterize the collagenase-stimulatory activity produced by epithelial cells, epithelial cell-conditioned culture medium was extracted under conditions that optimized the recovery of peptides and was subjected to ion-exchange batch extraction as well as reverse-phase and size-exclusion HPLC. Collagenase-stimulatory activities were mainly recovered in neutral extracts of epithelial cell-conditioned medium with an apparent molecular mass of 6 kDa. In conclusion, interstitial collagenase is produced by cervical stromal cells and not by cervical epithelial cells. Epithelial cells, however, secrete factors of low molecular size that stimulate stromal cell collagenase production.

The Book Corner

Abstract ION EXCHANGE AND SOLVENT EXTRACTION, Edited by J. A. Marinsky and Y. Marcus, A Series of Advances, Volume II, Marcel Dekker, Inc., New York, 400 pages, 1993. Price: $195.00 (USA) DRUG STEREOCHEMISTRY, Analytical Methods and Pharmacology, Second Edition, Edited by I.W. Wainer, Marcel Dekker, Inc., New York, 432 pages, 1993. Price: $165.00 (USA)

Urinary metanephrine and normetanephrine determined without extraction by using liquid chromatography and coulometric array detection

We describe a procedure for the direct measurement of metanephrine (MN) and normetanephrine (NMN) in hydrolyzed urine, using HPLC with coulometric array detection. Acid-hydrolyzed samples were diluted and filtered before separation by isocratic reversed-phase ion-pair chromatography. Eight serial coulometric sensors, set at incrementally increasing anodic potentials, were used to screen lower-oxidizing interferences and provide stepwise oxidation of the metanephrines. Voltammetric behavior across three adjacent sensors was used to assess resolution and aid in peak identification. Values obtained in commercial controls were consistently within the specified target range. Variability, expressed as CV, was 5.45-9.22% between runs and 1.60-4.52% within-run for both compounds. The limit of detection was 2.6 micrograms/L for MN and 2.8 micrograms/L for NMN, with a linear response to 15.0 mg/L for both analytes. Results from patients' samples correlated well with those by a method involving dual ion-exchange extraction (r = 0.963, n = 82 for MN; r = 0.9768, n = 83 for NMN). This procedure provided high selectivity and objective peak purity information while greatly simplifying sample preparation.

Mathematical simulation and calculation of the continuous countercurrent process of ion-exchange extraction of strontium from strongly mineralized solutions

The program “Countercurrent” is developed for the simulation of a continuous ionexchange extraction of strontium from strongly mineralized NaCl and CaCl2 solutions using a KB-4 carboxylic cation-exchanger in the countercurrent columns. The program allows one to calculate the conditions of Ca and Sr separation depending on the mode of operation at the sorption and regeneration stages, the residual Sr content on the overloaded sorbent, and the Sr separation on incompletely regenerated KB-4. It also makes it possible to find the optimal separation conditions. The program “Countercurrent” can be also used to simulate other ion-exchange processes.

Development and optimization of a liquid chromatographic method for the determination of gentamicin in calf tissues

A simple and sensitive method for the determination of gentamicin in calf tissues (muscle, liver, kidney and fat) based on liquid chromatography (LC) is described. A 5% (w/v) trichloroacetic acid solution was used to precipitate proteins. After centrifugation of the sample, the pH and ionic strength were adjusted for further purification by liquid—solid ion-exchange extraction using CM-Sephadex gel. A 100-μ1 aliquot of the eluate from the ion-exchange cartridge (in 0.05 M NaOH) was injected on to the LC column after adjustment of the pH and counter ion concentration. The chromatography consisted of an ion-pairing system with a mobile phase containing camphorsulphonate as the counter ion, a reversed-phase column (LiChrospher 100 RP-18 end-capped) and postcolumn derivatization with o-phthalaldehyde and 2-mercaptoethanol followed by fluorimetric detection. The three major components of gentamicin were eluted as a single peak. Recoveries ranged from 68 to 98% in tissue samples fortified with gentamicin at 0.05–3.2 μg g −1 levels. The limit of quantification was 50 ng g −1 in muscle and fat and 100 ng g −1 in liver and kidney.

The production, recovery, properties, and applications of americium and curium

Nuclear reactors produce mixtures of Am-241 and Am-242, and beta decay of plutonium produces radioactively pure Am-241. Curium is a product of intense neutron exposure of Pu-239. Separation and purification processes for americium and curium include ion exchange, precipitation, and both liquid-liquid and molten-salt extraction. This article reviews the principal production, recovery, and waste treatment processes and briefly discusses the chemical properties and uses of americium and curium.

A MOLECULAR MODELLING STUDY OF DICARBOXYLATE ANIONS AND ZINC OXALATE COMPLEX EXTRACTION BY DIPHOSPHONIUM EXTRACTANTS

Abstract A molecular modelling method is used as an aid to predict and to account for the results of solvent extraction of dianions by an ion-exchange extractants such as diphosphonium compounds (polymethylenebis(trioctylphosphonium)s abbreviated as CnBP2+). The extraction ability of CnBP2+ extractants was surprisingly dependent on the dianionic species and on the length of bridging methylene chain connecting the two phosphonium cationic centers which offers an effective molecular recognition field. The dianions studied are phthalate, isophthalate, terephthalate, dibenzoyltartrate and zinc oxalate complex. All of them have their negative charges carried by oxygen atoms. The extracted species considered for a dianion A2− are 1:1 and 2:2 ion-pair species such as (CnBP2+, A2−), (2 CnBP2+, 2 A2−rpar; with n = 2, 4, 6, 8, 10, 12. These ion-pair species are modelled and minimized. The total energy values obtained are processed to calculate the association energies of ion-pair species which allow comparison of 1...

Alkylated Lariat Ethers as Solvent Extraction Reagents: Surveying the Extraction of Alkali Metals by Bis-t-octylbenzo-14-crown-4-acetic Acid by Use of Potentiometric Two-Phase Titration

Abstract Two-phase potentiometric titrimetry was used to survey the extraction of alkali metal cations from aqueous chloride solution by the lipophilic, ionizable lariat ether bis-(t-octylbenzo)-14-crown-4-acetic acid (BOB14C4AA) in o-xylene. Analysis of the data indicates that ion-exchange extraction by the crown-carboxylic acid at low loading (i.e., low conversion of BOB14C4AA to its salt form) is stronger for lithium ion than for the other alkali metals. Little or no selectivity occurs at high loadings. In comparison with the long-chain carboxylic acid 2-methyl-2-heptylnonanoic acid (HMHN), BOB14C4AA extracts lithium and sodium at significantly lower pH; in the loading range of 0.1 to 0.7, the pH shift is 1.4–1.8 pH units for sodium ion and 1.7–2.3 pH units for lithium ion. The titration data are interpreted in terms of aggregated organic-phase species. In the case of lithium extraction, clear evidence was found for a species in which neutral BOB14C4AA participates in the organic-phase complexation of ...

Prediction of spouted bed reactor performance using kinetic models

AbstractThe form of the equation governing the kinetic model of a reactor depends on the mixing regime of the reacting phases and the conversion kinetics. The formation of detached flow in a spouted‐bed reactor results in backmixing of the solid material. Therefore, the processes in a spouted‐bed reactor can be described by a diffusion (quasihomogeneous) model equation. The paper compares the values of the production capacity of a spouted‐bed reactor calculated using the diffusion model with experimental values of the efficiency of green ultramarine oxidation (kinetic region), of oxidative calcination of some metal sulphides (mixed region), and of the ion exchange extraction of copper from solutions (diffusion region). The kinetics of the corresponding conversions are also described.

The effect of Streptomyces species on the survival of Salmonella in soil

A modified Chelex 100 ion-exchange extraction method was used to monitor streptomycete spores, streptomycete mycelia and Salmonella in soil. Salmonella dusseldorf in soil was inhibited by the bactericidal effect of streptomycin and by the growth of Streptomyces bikiniensis. The soil used in the experiments exerted an antimicrobial effect on S. dusseldorf. Competition between S. dusseldorf, Streptomyces lividans TK24 and Stm. bikiniensis ATCC 11062 was monitored in soil. In sterile amended soil Stm. lividans increased the survival of S. dusseldorf, whereas survival was reduced in the presence of the known streptomycin producer, Stm. bikiniensis. In the presence of S. dusseldorf the production of spores and mycelia by Stm. bikiniensis was reduced, and Stm. lividans sporulation was reduced but mycelia production increased. Evidence was seen for a beneficial effect between S. dusseldorf and Stm. lividans mycelia. In non-sterile unamended soil the survival of S. dusseldorf was increased in the presence of Stm. lividans, whereas Stm. bikiniensis had no effect. Stm. lividans and Stm. bikiniensis reduced the survival of S. dusseldorf in non-sterile amended soil, with the most dramatic reduction caused by Stm. bikiniensis. No such changes in the survival of S. dusseldorf were observed with non-sterile amended soil that had been treated with sludge. The presence of sludge in unamended soil increased the rate of Salmonella die-off. In unamended soil containing sludge the presence of Stm. lividans increased the survival of S. dusseldorf, whereas survival was reduced in the presence of Stm. bikiniensis. The data provided evidence of antibiosis in soil, relating to the possible production of streptomycin by Stm. bikiniensis.

The effect of Streptomyces species on the survival of Salmonella in soil

A modified Chelex 100 ion-exchange extraction method was used to monitor streptomycete spores, streptomycete mycelia and Salmonella in soil. Salmonella dusseldorf in soil was inhibited by the bactericidal effect of streptomycin and by the growth of Streptomyces bikiniensis. The soil used in the experiments exerted an antimicrobial effect on S. dusseldorf. Competition between S. dusseldorf, Streptomyces lividans TK24 and Stm. bikiniensis ATCC 11062 was monitored in soil. In sterile amended soil Stm. lividans increased the survival of S. dusseldorf, whereas survival was reduced in the presence of the known streptomycin producer, Stm. bikiniensis. In the presence of S. dusseldorf the production of spores and mycelia by Stm. bikiniensis was reduced, and Stm. lividans sporulation was reduced but mycelia production increased. Evidence was seen for a beneficial effect between S. dusseldorf and Stm. lividans mycelia. In non-sterile unamended soil the survival of S. dusseldorf was increased in the presence of Stm. lividans, whereas Stm. bikiniensis had no effect. Stm. lividans and Stm. bikiniensis reduced the survival of S. dusseldorf in non-sterile amended soil, with the most dramatic reduction caused by Stm. bikiniensis. No such changes in the survival of S. dusseldorf were observed with non-sterile amended soil that had been treated with sludge. The presence of sludge in unamended soil increased the rate of Salmonella die-off. In unamended soil containing sludge the presence of Stm. lividans increased the survival of S. dusseldorf, whereas survival was reduced in the presence of Stm. bikiniensis. The data provided evidence of antibiosis in soil, relating to the possible production of streptomycin by Stm. bikiniensis.

Stability and distribution constants of thallium(I) dithiocarbamates

Stability and distribution constants of thallium(I) chelates with diethyl-(I), pyrrolidine- (II), piperidine- (III), phenylethyl- (IV) and methylphenylethyldithiocarbamate (V) have been radiometrically determined using ion-exchange and solvent extraction methods. Stability constants of individual chelates do not change considerably, however, the distribution constants of neutral chelates increase in the order II<IV<I∼III<V.