Determination of weight distribution ratios of Pa(V) and Np(V) with some extraction chromatography resins and the AG1-X8 resin

Literature data on distribution ratios (D_w) of Np(V) and Pa(V) for the AG1-X8 resin are scarce whereas those related on resin capacity factors (k′) values for TEVA, TRU and U/TEVA resins are absent. Therefore, batch extraction experiments for Pa(V) and Np(V) from HCl and HNO₃ media were realized, at tracer scale, with AG1-X8 and EIChroM resins (TEVA, TRU and U/TEVA). Based on the new D_w and k′ values obtained in this study, a new protocol for Pa/Np separation has been developed leading to a better separation factor of 10⁵ and a chemical yield of 97 ± 3% and 99 ± 1% for Pa and Np, respectively. A separation of ²³¹Pa from uranium matrix was successfully tested.     

Chemical processing of 123I with a modified Bio-Rex 5 resin

The Bio-Rex 5 resin was used for the recovery of ¹²³I, producedin a cyclotron by irradiation of a ¹²⁴ Xe target. Initially fouranion exchange resins AG1-X8, AG2-X8, Amberlite IRA-93 and Bio-Rex 5 wereused, but none of them gave good separations. Bio-Rex 5, consisting of a largeportion of tertiary and a smaller portion of quaternary amino groups, wasthen modified so that the resin contained only tertiary amine functional groupsand this modified resin was used for the separation. The concentrations ofiodide solutions were ca 5 ppb and the volumes about 120 ml. For measurementof iodide, ¹³¹I was added as tracer. In this study 6 columns ofvarious sizes were used and the best of them, in terms of maximum recoveryand minimum volume of NaOH for elution, was selected for routine production.     

Determination of Phytic Acid in Urine by ICP Atomic Emission Spectrometry.

Abstract

A method to determine phytic acid within urine in the range 0.15–2 mg/l is reported. The method is based on the ICP atomic emission spectrometric determination of phosphorus, after previous separation and concentration of phytic acid using the anionic resin AG1-X8. The method has been applied successfully to determine phytic acid in synthetic urine and human urine.     

地质样品铁同位素自动固相萃取系统研究

研发了一种自动固相萃取系统,用于分离地质样品中铁同位素。系统有4个并行通道,可以一次处理4个样品。对于这4个样品,一次处理过程仅需24 min。选用AG1-X8阴离子交换树脂对花岗岩样品(GBW07103)中的铁进行萃取。在萃取过程中,当盐酸浓度大于6 mol/L时,铁形成络阴离子并被吸附在AG1-X8阴离子交换树脂上,其余阳离子被洗脱出来。用浓度为8 mol/L的HNO 3和H 2O洗脱铁,铁的洗脱体积为4 mL,铁可以被定量回收,回收率达到96.0%~107%。消除了测试过程中的基体影响,提高了样品处理效率,减少了人为污染风险,是一个多元化样品处理工具。     

Purification and separation of <Superscript>239+240</Superscript>Pu and <Superscript>241</Superscript>Am in biological samples by anion-exchange and extraction chromatography for high resolution alpha-spectrometry analyses

Many biological samples (urines and faeces) have been analyzed by means of chromatographic extraction columns, utilizing two different resins (AG 1-X2 resin chloride and TRU), in order to detect the possible internal contamination of ^239+240Pu and ²⁴¹Am for some workers of a reprocessing nuclear plant in the decommissioning phase. The results obtained show on one hand the great suitability of the first resin for the determination of plutonium, and on the other, the great selectivity of the second one for the determination of americium.     

Behaviour of Mo,Al, As,Cs, Sn,Sb, Pd,Rh, Ru,Ge, Se and Te on the macroporous resin AG MP-1 in alkaline medium

The behaviour of Mo and some other elements on Ag MP-1 in alkaline medium was investigated. Equilibrium distribution coefficients, K_d, are presented for Mo on the anion exchangers AG 1-X2, AG 1-X4, AG 1-X8 and AG MP-1, and for some elements on AG MP-1 in alkaline medium. An anion exchange chromatographic separation of Mo from some of these elements is described and some results obtained with this method are reported.     

A straightforward protocol for Hf purification by single step anion-exchange chromatography and isotopic analysis by MC-ICP-MS applied to geological reference materials and zircon standards

A straightforward one-step Hf purification protocol for geological samples using common anion-exchange chromatography and isotopic measurements by multiple collector inductively coupled plasma mass spectrometry (MC-ICP-MS) is described in this paper. The sample is dissolved in concentrated HF–HNO₃ mixtures with round-bottom Savillex? Teflon screw-top capsules or high-pressure stainless steel jacketed Teflon bombs. After complete dissolution, the chemical separation between Hf and isobarically interfering elements such as Lu, Yb, and matrix elements like Ti, is performed and achieved simultaneously using a common one-step anion exchange resin (AG1-X8). The Hf yields are >90% and total procedural blanks are lower than 20 pg. This protocol not only avoids using multiple-stage ion exchange resins, but also eliminates perchloric acid to break down fluorides after HF treatment of the sample. In addition to whole rock, this protocol is also practical for zircon and baddeleyite Hf purification prior to isotopic measurement. New Hf isotopic data for zircon 91500, Temora, CN92-1 and FM0411, together with Phalaborwa baddeleyite are presented for this method. Multiple analyses of the international geological reference materials and standard zircon and baddeleyite used in U–Pb geochronology demonstrate that this method is simple, economic, efficient and reproducible.     

Recovery of <Superscript>65</Superscript>Zn from waste solutions from gallium targets at Brookhaven Linac Isotope Producer

A procedure for recovery of ⁶⁵Zn from acidic Ga-rich solutions generated in ⁶⁸Ge production process was developed and implemented in a “hot cell” environment. A one step simple separation was carried out on anion exchange column filled with Biorad AG1-X8 resin. With ⁶⁵Zn recovery yields of more than 95% this procedure is currently routinely used at Brookhaven Linac Isotope Producer.     

Protonation and ion exchange equilibria of weak base anion-exchange resins

Protonation and ion exchange equilibria of weak base anion-exchange resins, in which tertiary amine moieties were introduced as a functional group, were investigated by applying NMR spectroscopy to species adsorbed into the resins. ³¹P NMR signals of the phosphinate ion in the resin phases shifted to a lower field due to the influence of protonation of the tertiary amine groups of the resins in the pH range of 4-10. Protonation constants of the tertiary amine groups in styrene-divinylbenzene (DVB)-based resins were estimated to be K_H = 10^6.4 for Amberlite IRA96 and 10^6.5 for DIAION WA30 by the ³¹P NMR method using the phosphinate ion as a probe species. In addition to the low field shift caused by the protonation of the tertiary amine moieties, another low field shift was observed for the phosphinate ion in acrylic acid-DVB-based resins at a rather high pH. This shift should be due to an unexpected deprotonation in the acrylic resin: a tautomerism accompanying the proton release from the amide form to the imide one in the functional group, thus, the resin could exhibit a cation exchange property at the high pH. Protonation constants of the tertiary amine moieties in the acrylic resins were estimated to be 10^8.8 for DIAION WA10, 10^9.0 for Amberlite IRA67 and 10^9.3 for Bio-Rad AG 4-X4 on the basis of the Henderson-Hasselbalch equation using the resin phase pH estimated by the ¹³³Cs and ¹H NMR signal intensities.     

The Kinetics of 1,8-Dihydroxy-2-(Pyrazol-5-ylazo)-Naphthalene-3,6-Disulfonic Acid Immobilization on Anion Exchangers

The sorption of 1,8-dihydroxy-2-(pyrazol-5-ylazo)-naphthalene-3,6-disulfonic acid onto the anion exchange resins Dowex 1-X8 and Dowex 2-X8 from aqueous solutions of between pH 1 and 10 was studied spectrophotometrically. Conditions for obtaining modified sorbents with a given capacity for the azo compound were investigated. The absorption and reflectance spectra of the sorbed dye were traced. The immobilized reagent retained chromic characteristics similar to those it had in solution. The mechanism of sorption was investigated under static conditions in the temperature range of 0 to 25°C by following the amount of sorbed dye as a function of contact time. The sorption was a first-order process in all cases. Pore diffusion was found to be the rate-limiting step in the sorption process. Diffusion coefficient values of from 6.0 × 10^–7 to 7.4 × 10^–7 cm²/s were calculated from the experimental results. The values of the activation energy of PACA sorption were found to be –8.56 and –8.05 kJ/mol for Dowex 1-X8 and Dowex 2-X8, respectively.     

Preconcentration of trace metal ions by combined complexation-anion exchange : Part I. Cobalt,zinc and cadmium with 2-(3′-sulfobenzoyl)-pyridine-2-pyridylhydrazone

The ligand 2-(3′-sulfobenzoyl)pyridine-2-pyridylhydrazone forms anionic complexes with Fe, Co, Ni, Cu, Zn, Cd, Hg and Pd which demonstrate high affinities for anion-exchange resins. The behavior of Co, Zn and Cd was studied in detail, with respect to pH, flow rate, ligand/metal ratio, volume, concentration and percentage retention of the anionic complex on the Bio-Rad AG1-X2 resin. At optimal conditions, Co, Zn and Cd are quantitatively retained; Zn and Cd are removed completely by 2 M HNO₃ or 1 M H₂SO₄, and Co by 12 M HCl and 1 M HNO₃. Concentration enhancements up to 300-fold can be easily achieved. The complexes can be left on the columns for 48–96 h and still be quantitatively recovered. A ligand-loaded resin column can also be used to remove Co, Zn and Cd from solution. Batch experiments were used to determine distribution coefficients for the metal complexes.     

HPLC determination of volatile phenols in wines

Summary An alternative to the traditional solvent extraction method used to extract and rapidly quantify ethyl-and vinylphenol and ethyl-and vinylgaiacol from wine is presented. The method is based on retention of volatile phenols on adsorbants. Among the tested resins, the most efficient, AG 2-X8 (anion exchange resin), worked as well with a synthetic solution as with wines. The percolation of clarified wine adjusted to pH 9 on this resin permits, in particular, the elimination of organic acids. Phenols are not eluted after rinsing the column with 1N HCl, but are eluted with methanol after this treatment. Good recovery (91 %) and good repeatability are observed. The eluate is directly analysed by HPLC on an RP18 column after two-fold dilution in water. The four volatile phenols were completely separated and detected by UV at 280 nm with high sensitivity (20–40 ppb). No interference with other compounds were noted in the different wines analysed.     

Cyclotron production of 68Ge with a Ga2O target

Systematic information of exchange behavior of Ge(IV) and Ga(III) in varying oxalic acid (0.05M and 0.25M) and sulphuric acid (0.005M-2M range) mixtures is presented. These findings were used to develop a separation involving ⁶⁸Ge from a Ga₂O target material. A method based on acid dissolution of the target and chromatography on an anion exchange resin (Bio-Rad^Ò AG1-X8) was developed. The separated ⁶⁸Ge has high radionuclidic purity and an acceptable chemical purity.     

Separation of the no-carrier-added 109Cd from Ag, Cu and 65Zn by use of a precipitation and AG1-X8 resin

The ¹⁰⁹Cd radionuclide was produced in the cyclotron via ^natAg(p,n)¹⁰⁹Cd reaction. The radiochemical separation of ¹⁰⁹Cd from silver and non-isotopic impurities comprised of two stages. The optimum conditions of the ¹⁰⁹Cd separation methods were: Ag precipitation with 0.015 M HCl and Cu and ⁶⁵Zn by use of 0.015 M HCl on AG1-X8 strong anion-exchange resin. Chemical and radionuclidic purity of ¹⁰⁹Cd were measured by ICP-AES and gamma-ray spectrometry respectively. Recovery yield and radionuclidic purity were obtained 99.7% and 99%, respectively.     

Chemical separation of enriched cadmium target from copper backing in cyclotron production of radioisotope 111In

A radiochemical purification procedure was developed for the separation of enriched cadmium (¹¹¹Cd and ¹¹²Cd) from natural copper that used as backing; and was based upon the chromatographic adsorption. The separation of copper from cadmium was studied in this work. The ions were selectively separated from aqueous solution. Ion-exchange chromatography was employed as a column (1.5 cm i.d. and 15 cm length) with AG1-X8 resin (chloride form, 100–200 mesh) and a flow rate of 1–2 ml/min throughout the separation. 6 M HCl media was used for the adsorption of Cd and Cu on the resin. Then, Cu was eluted by 2 M HCl and Cd by 100 ml 0.5 M HNO₃. The amount of Cu and Cd ions in the final solution (0.5 M HNO₃) were measured by pulse polarographic method and the concentration of Cu was found to be <0.1 ppm. The Cd was quantitatively recovered and the recovery yield from ion-exchange chromatography was greater than 96 %.     

Separation of vanillylmandelic (VMA) and homovanillic (HVA) acids from urine for assay by a two resin column system

A procedure is described for separating vanillylmandelic acid (VMA) and homovanillic acid (HVA) from urine so that they can be assayed by chemical means or gas chromatography. The process comprises passing a threefold diluted urine over cation exchange column (AG 50W-X12) to remove catecol amines and amino acids. The VMA and HVA is then adsorbed from the diluted urine to an anion exchange column (AG 2-X8). After washing with water, the HVA and VMA are eluted with an NaCl-K₂CO₃ solution. The VMA can be determined by oxidation to vanillin directly. By extraction with n-pentanone-2, after acidification and evaporation to dryness, the residue may be redissolved for processing or treated with a methylating reagent for gas chromatography. For the latter purpose, 4-methoxy benzophenone is recommended as the internal standard.     

Analysis of Adenosine and Other Adenine Compounds in Patients With Immunodeficiency Diseases

Abstract

Adenine compounds can be measured in picomole amounts using liquid chromatography of the fluorescent 1, N⁶-etheno derivatives. The limit of detection for the etheno derivatives in tissue extracts, however, is tissue-dependent due to interference by nucleotides and fluorescent components which are normally present. Prior to derivatization nucleotides were partially removed from extracts of lymphocytes and erythrocytes by treatment with Dowex AG1-X2 anion exchange resin. Samples were analyzed using either a Partisil PXS 10/25 SCX column eluted with 100 mM NH₄H₂PO₄, pH 4.5, at a flow rate of 2 ml/min; or using two μBondapak/C₁₈ reversed-phase columns eluted with 5 mM KH₂PO,₄:25% methanol (V/V) pH 7.5, at a flow rate of 1 ml/min. Adenosine was found to be 0.07 nmole/ml in normal adult human plasma. The urine of a child with severe combined immunodeficiency disease associated with absence of adenosine deaminase contained a normal amount of adenosine (5–6 nmole/ml), but contained a high level (～60 nmole/ml) of deoxyadenosine. Deoxyadenosine was not detected (<0.01 nmole/ml) in normal adult urine. Because of its sensitivity and selectivity, this method of analysis should be applicable to studies of the physiological roles of adenine compounds.     

Physicochemical Characterization of Poly(vinyl chloride). II. Molecular Weight Distributions

Abstract

Molecular weight distributions in poly(vinyl chloride) resins have been determined from simple viscosity measurements. Ratio of 11% solution viscosity to intrinsic viscosity yielded a figure which has been correlated with molecular weight distributions obtained (1) from the ratio of weight-average to number-average molecular weights and (2) from gel permeation chromatography. Ratio of viscosities is thus a useful short-cut technique for obtaining approximate molecular weight distributions in poly(vinyl chloride) resins which have 0. 77 < [η] < 1.15 and 1. 6 < ROM < 2. 8.     

Desalting and Freeze-Drying Techniques to Prepare Plant Derived Neutral Sugar Extracts for Quantitative HPLC

Abstract

Desalting and sample concentration are frequent prerequisites for the quantitative HPLC analysis of sugars and polyhydric alcohols in extracts of biological material. However, desalting using Dowex mixed-bed resins and sample concentration by conventional freeze-drying adversely affect the recovery of the carbohydrates being analysed, making quantitation almost impossible. In the present paper we report modified sample preparation procedures which overcome this technical problem. Efficient desalting was achieved by batchwise deionisation with an Amberlite mixed-bed deionisation resin, incorporating thymolphthalein to provide a sensitive indicator of resin exhaustion. Complete recovery of neutral sugars was possible provided the resin was subsequently washed with water. Concentration of dilute extracts with full recovery of neutral sugars was achieved by freeze-concentration using a Savant Speed-Vac centrifugal freeze-concentrator. The combination of these desalting and freeze-concentration procedures gave excellent recoveries of the neutral sugars together with dramatic improvements in HPLC column life and chromatographic resolution.     

Removal of Trace Contaminants from Water Using New Chelating Resins

Abstract

The modification of cross‐linked polyacrylamide (CPAAm) and incorporation of methyl thiourea (MeTU) or phenyl thiourea (PhTU) group were utilized in the preparation of two new chelating resins CPAAm‐EDA‐MeTU (resin I) and CPAAM‐EDA‐PhTU (resin II), [EDA=ethylenediamine]. The prepared resins were characterized by elemental analysis and IR spectroscopy. The sorption behaviors of Cd(II), Pb(II), and Zn(II) ions on the prepared resins were studied and the optimum sorption conditions for the tested metal ions were determined. The optimum pH value for the sorption of Cd(II) and Zn(II) ions on both resins I and II was ranged between 7–8. The prepared new resins show very little affinity towards Pb(II) ion. The maximum experimental sorption capacities of resin I towards Cd(II) and Zn(II) ions were 3.2 and 0.6 mmol g^?1, respectively, and that of resin II were and 0.6 mmol g^?1 in the same prescribed order. Langmuir and Freundlich isotherm constants and correlation coefficients for the present system were calculated and compared. The thermodynamic parameters (ΔG°, ΔH°, and ΔS°) for cadmium and zinc sorption on the prepared resins were also determined from the temperature dependence.