Ion chromatographic determination of transition metals in irradiated nuclear reactor surveillance samples

The determination of transition metal ions in radioactive (±25 Ci/g) low-alloy steels (nuclear reactor surveillance samples) by ion chromatography (IC) is described. The analysis has been done directly without prior separation of the iron matrix. The eluted metal ions have been detected with a UV-visible spectrophotometric detector after post-column complexation with 4-(2-pyridylazo)resorcinol. The results are in a good agreement with the certified values for the standard reference material used. The method was applied to nuclear reactor surveillance samples for the determination of Cu, Mn, Co and Ni.     

沉淀/共沉淀-膜富集-X射线荧光法快速分析近岸海水中的重金属

建立了近岸海水中多种重金属(铁、镍、锰、铜、锌及铅)的氢氧化物和硫化物的沉淀/共沉淀-膜富集-X射线荧光测定法.在海水样品中加入沉淀剂,使重金属离子生成氢氧化物或硫化物沉淀.沉淀经过滤截留,富集在膜上,直接以手持式X射线荧光仪检测.富集100 mL水样时,两种沉淀法的测定线性范围均为12.5～400 μg/L,即测定限均为12.5 μg/L.对各重金属浓度为100μg/L的试样连续测定7次,相对标准偏差(RSD)为3.7％～6.4％;氢氧化物沉淀法的检出限在1.32～7.84 μ g/L之间;硫化物沉淀法为1.94～11.0 μg/L.用本方法成功测定了厦门近岸海域及九龙江河口海水中的重金属浓度.基于样品酸化与否及过滤先后顺序的不同,本方法可用于海水和河口水样中可溶态、溶解态及游离态重金属的现场快速分析.     

Determination of uranium, thorium and plutonium isotopes by ICP-MS

Quantitative and isotopic measurement of actinide elements is required in many circumstances in the nuclear industry. For example, determination of very low levels of these alpha emitters in human urine samples is used to assess the internal committed dose for nuclear workers. Quantifying actinide isotopes in radioactive waste from nuclear processing and nuclear facility decommissioning provides important information for waste management. Accurate determination of the uranium isotopic ratios in reactor fuels provides fuel burnup information. Inductively coupled plasma mass spectrometry (ICP-MS) has been used for the determination of Th, U, and Pu in various samples including urine, nuclear waste, and nuclear fuel in our laboratory. In order to maximize the capability of the technique and ensure quality analyses, ICP-MS was used to analyze samples directly, or after pre-treatment to separate complicated matrices or to concentrate the analyte(s). High-efficiency sample introduction techniques were investigated. Spectral interferences to minor isotopes caused by peak tails and hydride ions of major actinide isotopes were studied in detail using solutions prepared with light and heavy waters. The quality of the isotopic ratio measurement was monitored using standard reference materials.     

Controlled-pore silica glass modified with N-propylsalicylaldimine for the separation and preconcentration of trace Al(III), Ag(I) and Hg(II) in water samples.

Controlled-pore silica glass modified with N-propylsalicylaldimine (SCPSG) has been investigated as a surface-active matrix for the separation of some metal ions. The porous silica glass base was confirmed to have better stability towards hydrolysis in aqueous solution buffered at pH=9 in comparison to silica gel, which showed twice the surface area of controlled-pore silica glass. The different analytical parameters affecting the batch mode separation and preconcentration of trace Al(II), Ag(I) and Hg(II) in environmental samples using SCPSG, prior to their determination using inductively coupled plasma mass spectrometry (ICP-MS), were studied. The optimum conditions are pH 9.0 +/- 0.1, time of stirring 30 min and the eluent concentration 0.5 mol dm(-3) HNO3. The ion-exchange capacity of SCPSG with respect to Al(III), Ag(I) and Hg(II) was 0.27, 0.18 and 0.23 mmol g(-1), respectively. The recovery values for the metal ions were 96.8 +/- 0.86, 98.1 +/- 0.60 and 96.2 +/- 1.06%, and the analytical detection limits were 26.1, 1.49 and 0.44 pg cm(-3), respectively, for a preconcentration factor of 100. The method has been applied to the determination of the investigated metal ions in natural water samples as well as certified and reported samples and the results were found to be accurate.     

On-site monitoring of uranium in low level liquid waste streams using U-Br-PADAP strip indicator paper technique

A simple, rapid and selective colorimetric technique for the determination of low level concentration of uranium in nuclear waste streams is described. The proposed method is based on the intensity of U-Br-PADAP (Uranium-2-(5-Bromo-2-pyridylazo)-5-diethyl-aminophenol) colour formed on strip indicator paper. The effect of pH, concentration of chromogenic reagent, stability of the colour, volume of buffer solution and interference of metal ions were studied. The detection limit is 1 mg/L. Various uranium samples have been tested for the validation of the proposed method. The results obtained are reproducible and good agreement with those obtained by the standard technique.     

Trace analysis and speciation of copper by application of an urease reactor

Summary A method for metal speciation using an enzyme reactor is described. The enzyme urease is immobilized on a polymer support. The parameters of the inhibition procedure are investigated for the determination of copper in drinking and surface water samples. The results are compared with those obtained by atomic absorption spectrometry. It has been found that the enzyme urease was inhibited only by free copper ions.Dedicated to Professor Dr. Wilhelm Fresenius on the occasion of his 80th birthday     

Quinalizarin anchored on Amberlite XAD-2. A new matrix for solid-phase extraction of metal ions for flame atomic absorption spectrometric determination

Amberlite XAD-2 has been functionalized by coupling it to quinalizarin [1,2,5,8-tetrahydroxyanthraquinone] by means of an -N = N- spacer. Elemental analysis, thermogravimetric analysis, and infrared spectra were used to characterize the resulting new polymer matrix. The matrix has been used to preconcentrate Cu(II), Cd(II), Co(II), Pb(II), Zn(II), and Mn(II) before their determination by flame atomic absorption spectrometry (FAAS). UO2(II) has been preconcentrated for fluorimetric determination. The optimum pH values for maximum adsorption of the metals are between 5.0 and 7.0. All these metal ions are desorbed (recovery 91-99%) with 4 mol L(-1) HNO3. The adsorptive capacity of the resin was found to be in the range 0.94-5.28 mg metal g(-1) resin and loading half-life (t1/2) between 5.3 and 15.0 min. The effects of NaF, NaCl, NaNO3, Na2SO4, Na3PO4, Ca(II), and Mg(II) on the adsorption of these metal ions (0.2 microg mL(-1)) are reported. The lower limits of detection for these metal ions are between 1 and 15.0 microg L(-1). After enrichment on this matrix flame AAS has been used to determine these metal ions (except the uranyl ion) in river water samples (RSD < or = 6.5%); fluorimetry was used to determine uranyl ion in well water samples (RSD < or = 6.3%). Cobalt from pharmaceutical vitamin tablets was preconcentrated by use of this chelating resin and estimated by FAAS (RSD approximately 4%).     

Use of miniaturised isotachophoresis on a planar polymer chip to analyse transition metal ions in solutions from metal processing plants

An electrolyte system, using malic acid as a complexing agent, has been developed to allow the determination of transition metal cations using miniaturised isotachophoresis. The method allowed the simultaneous determination of Mn2+, Cr3+, Fe2+, Co2+, Zn2+ and Ni2+ to be made without interference from other common ions. Limits of detection were calculated to be in the range 0.5-1.0mg l(-1) for Mn2+, Cr3+ Co2+ and Zn2+ and 2.0 mg l(-1) for Fe2+ and 4.7 mg l(-1) for Ni2+. The successful analysis of five industrial samples, containing a range of these metal ions, obtained from metal processing plants were achieved in under 13 min. The separations were performed on a poly(methyl methacrylate) chip with integrated platinum wire conductivity detection electrodes.     

Preconcentration of Cr(III), Co(II), Cu(II), Fe(III) and Pb(II) as calmagite chelates on cellulose nitrate membrane filter prior to their flame atomic absorption spectrometric determinations

A method for the preconcentration and determination of Cr(III), Co(II), Cu(II), Fe(III) and Pb(II) ions by atomic absorption spectrometry has been described. The method was based the collection of metal-calmagite complexes on a soluble cellulose nitrate membrane filter. The detection of the solution was obtained by flame atomic absorption spectrometry (FAAS) after completely dissolving the membrane with 0.5 ml of nitric acid at 80 degrees C. The metal ions were recovered quantitatively at pH 8. Various factors which affect the collection and determination of metal ions such as, type and size of the membrane filter, solvent for dissolution of the species retained on the filter were investigated. The detection limits were varying 0.06 mug l(-1) for Cu to 2.5 mug l(-1) for Cr. An application of the proposed method for analyte ions in mineral and tap water samples was also described with satisfactory results (recoveries >95%, relative standard deviations <10%).     

Online coupling of ultraviolet titanium dioxide film reactor with poly(methyl methacrylate) solid phase extraction–inductively coupled plasma mass spectrometry for speciation of trace heavy metals in freshwater

To rapidly discriminate dissolved labile and stable organic-complexed metal ions, a fully automated approach comprising a photocatalyst-assisted digestion reactor (PADR), a non-functionalized poly(methyl methacrylate) (PMMA) solid-phase extraction (SPE) column, and inductively coupled plasma-mass spectrometry (ICP-MS) instrumentation was developed. To separate labile dissolved metals from other concomitant metal complexes, a non-functionalized PMMA bead was used as the SPE adsorbent because of its selective interaction with labile metal ions. The PMMA SPE–ICP-MS hyphenated system was optimized, and its analytical reliability was confirmed by using it to analyze the certified reference material—NIST 1643e (artificial saline water). Detection limits (σ = 3, n = 7) for all analyte ions (Ni, Cu, Zn, Cd, and Pb), which ranged from 0.005 to 0.186 μg L^{− 1}, could be reached; therefore, this technique appeared uniquely suited to determining levels of trace elements in most natural freshwater samples. To determine the total quantity of dissolved metals, a new digestion reactor (PADR) was developed for online conversion of metal–organic complexes to their labile forms. Compared to conventional photolysis methods, the digestion time improved considerably and the digestion efficiency for organic substances was excellent (> 90%) in the PADR format, with a very short resident time of 10 min. After construction of the PADR–PMMA SPE–ICP-MS hyphenated system, the speciation potential of our developed method was evaluated by analyzing three intentionally contaminated water samples. Results indicated that our developed hyphenated system is effective for online determination of total, labile, and metal–humic complexes in freshwater samples and that is capable of providing representative metal speciation patterns for different aquatic systems.     

Enrichment of iron(III), cobalt(II), nickel(II), and copper(II) by solid-phase extraction with 1,8-dihydroxyanthraquinone anchored to silica gel before their determination by flame atomic absorption spectrometry

A chelating matrix prepared by immobilizing 1,8-dihydroxyanthraquinone on silica gel modified with 3-aminopropyltriethoxysilane has been characterized by use of cross-polarization magic angle spinning (CPMAS) NMR, diffuse reflectance infrared Fourier transformation (DRIFT) spectroscopy, and thermogravimetric analysis and used to preconcentrate Fe(III), Co(II), Ni(II), and Cu(II) before their determination by flame atomic absorption spectrometry. The optimum pH ranges for quantitative sorption are 6.5-8.0, 6.0-7.0, 6.0-8.0, and 7.0-8.5 for Cu, Fe, Co, and Ni, respectively. All the metal ions can be desorbed with 2 mol L(-1) HCl or HNO3. The sorption capacity ( micromol g(-1) matrix) and preconcentration factor were 226.6, 250; 365.6, 300; 101.8, 150; and 109.0, 250 for Cu, Fe, Co, and Ni, respectively. The lowest concentration for quantitative recovery was 4.0, 3.3, 6.6, and 4.0 ng mL(-1), respectively for the four metal ions. The limits up to which electrolytes NaNO3, NaCl, NaBr, Na2SO4, and Na3PO4 and cations Ca(II) and Mg(II) can coexist with the four metal ions during their sorption without adverse effect are reported. The simultaneous enrichment and determination of all the four metals is possible if the total load of metal ions is less than the sorption capacity. Flame AAS was used to determine the metal ions in underground, tap, and river water samples (RSD相似文献   

Solid phase extraction studies on cellulose based chelating resin for separation,pre-concentration and estimation of Cu2+and Ni2+

Chelating resins based on biopolymers, specifically cellulose, offers a green analytical method for determination of metal ions at trace levels present in various samples. It offers a fast, accurate and simple method for separation and pre-concentration of metal ions at low concentrations, prior to their determination by instrumental method. Cellulose based chelating resin (CELL-GLY) has been synthesised by immobilising glycine on it. CELL-GLY was used for the determination of trace amounts of Cu²⁺ and Ni²⁺ from aqueous solutions before their determination by FAAS. The preparation of CELL-GLY involves simple steps, based on natural and easily available biopolymer cellulose, which makes its use as chelating resin is a green method. The Cu²⁺ and Ni²⁺ can be quantitatively recovered from the CELL-GLY in the pH range 4.8–6.9 and 6.9-7.8 respectively with a recovery of more than 95% for each of these metal ions. Recovery of these metal ions using CELL-GLY was quantitative up to 35 °C. The detection limits for copper and nickel by FAAS were 1.20 ppb and 1.40 ppb, respectively. The method was successfully employed for the determination of trace amounts of Cu²⁺ and Ni²⁺ in various samples.     

Fluorescent ion-imprinted polymers for selective Cu(II) optosensing

This paper describes the synthesis and characterization of a fluorescent ion-imprinted polymer (IIP) for selective determination of copper ions in aqueous samples. The IIP has been prepared using a novel functional monomer, 4-[(E)-2-(4′-methyl-2,2′-bipyridin-4-yl)vinyl]phenyl methacrylate (abbreviated as BSOMe) that has been spectroscopically characterized in methanolic solution, in the absence and in the presence of several metal ions, including Cd(II), Cu(II), Hg(II), Ni(II), Pb(II), and Zn(II). The stability constant (2.04 × 10⁸ mol⁻² l²) and stoichiometry (L₂M) of the BSOMe complex with Cu(II) were extracted thereof. Cu(II)-IIPs were prepared by radical polymerization using stoichiometric amounts of the fluorescent monomer and the template metal ion. The resulting cross-linked network did not show any leaching of the immobilized ligand allowing determination of Cu(II) in aqueous samples by fluorescence quenching measurements. Several parameters affecting optosensor performance have been optimized, including sample pH, ionic strength, or polymer regeneration for online analysis of water samples. The synthesized Cu(II)-IIP exhibits a detection limit of 0.04 μmol l⁻¹ for the determination of Cu(II) in water samples with a reproducibility of 3%, exhibiting an excellent selectivity towards the template ion over other metal ions with the same charge and close ionic radius. The IIP-based optosensor has been repeatedly used and regenerated for more than 50 cycles without a significant decrease in the luminescent properties and binding affinity of the sensing phase.     

1,8-Dihydroxyanthraquinone anchored on silica gel: synthesis and application as solid phase extractant for lead(II), zinc(II) and cadmium(II) prior to their determination by flame atomic absorption spectrometry

A new chelating matrix has been prepared by immobilizing 1,8-dihydroxyanthraquinone (DHAQ) on silica gel modified with (3-aminopropyl)triethoxysilane. After characterizing the matrix with thermogravimetric analysis (TGA), cross polarization magic angle spinning (CPMAS) NMR and diffuse reflectance infrared fourier transformation (DRIFT) spectroscopy, it has been used to preconcentrate Pb(II), Cd(II) and Zn(II) prior to their determination by flame atomic absorption spectrometry. The optimum pH ranges for quantitative sorption are 6.0-7.5, 7.0-8.0 and 6.0-8.0 for Pb, Zn, and Cd, respectively. All the metal ions can be desorbed with 2 mol l(-1) HCl/HNO(3). The sorption capacity of the matrix has been found to be 76.0, 180.0 and 70.2 mumol g(-1) for Pb, Zn and Cd, respectively, with the preconcentration factor of approximately 200. The limits upto which electrolytes NaNO(3), NaCl, NaBr, Na(2)SO(4), Na(3)PO(4) sodium citrate, EDTA, glycine and humic acid and cations Ca(II), Mg(II), Cu(II), Co(II), Ni(II), Mn(II) Al(III), Cr(III) and Fe(III) can co-exist with the metal ions during their sorption without any adverse effect are reported. The lowest concentration of metal ions for quantitative recovery is 5.0 ng ml(-1) The simultaneous enrichment and determination of all the metals is possible if total load of metal ions is less than sorption capacity. The flame AAS was used to determine these metal ions in underground, tap and river water samples (relative standard deviation (R.S.D.)相似文献   

Enzymatic flow-injection determination of urea in blood serum using potentiometric gas sensor with internal nonactin based ISE

Ion-selective electrode with cellulose triacetate membrane containing nonactin is employed for the potentiometric detection of ammonia produced in biocatalytic reaction in flow-injection system with enzyme reactor. The elimination of interferences occurring in the presence of alkali metal ions was achieved by covering a nonactin membrane with outer hydrophobic gas permeable membrane. The obtained flow-injection response to ammonia indicates a possibility of ammonia determination down to 10 microM ammonia. In the flow-injection system for urea determination 200 microl of 10-fold diluted blood serum sample was injected into carrier stream of distilled water merged with TRIS buffer, passed through the urease flow-through reactor and then after merging with NaOH stream delivered to the detector. It was found in several series of natural blood serum samples, that the correction for endogenous ammonia in such a determination is not indispensable.     

Solid phase extraction of trace metals in water and leafy vegetables using a resin functionalized with potassium 2-benzoylhydrazinecarbodithioate and determination by ICP–AES

A solid phase extraction method for the determination of Cu(II), Mn(II) and Zn(II) metal ions in natural water and leafy vegetable samples by ICP-AES was developed. The method was based on the sorption of metal ions onto Amberlite XAD-16 functionalized with a new chelating ligand potassium 2-benzoylhydrazinecarbodithioate (Amberlite XAD-16-PBHCD) and elution with nitric acid. The optimum experimental conditions for the quantitative sorption of the three metal ions, namely, effect of pH, sample volume, flow rate, concentration of eluent, sorption capacity, kinetics of sorption, and the effect of diverse ions on the sorption of analytes have been investigated. All the metal ions were quantitatively retained by the functionalized resin at pH 5.0 and sorbed metals could be eluted with 2.0?M HNO₃. The detection limits were 5.6, 4.5 and 1.8?µg?L^?1 for Cu(II), Mn(II) and Zn(II), respectively. The developed method was applied for the determination of Cu(II), Mn(II) and Zn(II) in water and leafy vegetable samples.     

Derivative spectrophotometric determination of iridium after preconcentration of its 1-(2-pyridylazo)-2-naphthol complex on microcrystalline naphthalene

Iridium is preconcentrated from the large volume of its aqueous solution using 1-(2-pyridylazo-2-naphthol) (PAN) on microcrystalline naphthalene in the pH range of 4.5-6.0. The solid mass after filtration is dissolved with 5 ml of dimethylformamide (DMF) and the metal determined by first derivative spectrophotometry. The detection limit is 20 ppb (signal to noise ratio = 2) and the calibration curve is linear over the concentration range 0.25-75.0 mug in 5 ml of the final DMF solution with a correlation coefficient of 0.9996 and relative standard deviation of +/- 1.1%. Various parameters such as the effect of pH, volume of aqueous phase, choice of solvent, reagent and naphthalene concentration, shaking time and interference of a number of metal ions on the determination of trace amount of iridium have been studied in detail to optimize the conditions for its determination in synthetic samples corresponding to various standard alloys and environmental samples.     

Application of High Performance Liquid Chromatography to the Analysis of Nuclear Materials

Abstract

A small-particle (13 μm) styrene-divinylbenzene cation-exchange resin has been used for the separation and determination of trace metals in nuclear materials such as steels, Ni-Cr-Fe alloys, zirconium, and uranium. The eluted metal ions, which included Mn, Fe, Co, Ni, Cu, Zn and Pb, were monitored with a variable wavelength detector after a post-column reaction with 4-(2-pyridylazo)-resorcinol. The metal ions were determined at 10^?4 to 1% (w/w) levels by direct injection of solutions of the materials. Interference from uranium, due to the reaction between uranium and the reagent used for detection, was removed either with a masking agent or by a coupled-column technique.     

Determination of heavy metals at sub-ppm levels in seawater and dialysis solutions by FAAS after tetrakis(pyridine)-nickel(II)bis(thiocyanate) coprecipitation.

A coprecipitation method has been developed for the determination of Cr(III), Mn(II), Fe(III), Co(II), Cu(II), Cd(II) and Pb(II) ions in aqueous samples by flame atomic absorption spectrometry (FAAS) with the combination of pyridine, nickel(II) as a carrier element and potassium thiocyanate as an auxiliary complexing agent. The obtained coprecipitates were dissolved with nitric acid and measured by FAAS. The coprecipitation conditions, such as the effect of the pH, amounts of nickel, pyridine and potassium thiocyanate, sample volume, and the standing time of the precipitate formation were examined in detail. It was found that the metal ions studied were quantitatively coprecipitated with tetrakis(pyridine)-nickel(II)bis(thiocyanate) precipitate (TP-Ni-BT) in the pH range of 9.0 - 10.5. The reliability of the results was evaluated by recovery tests, using synthetic seawater solutions spiked with the analyte metal ions. The obtained recoveries ranged from 96 to 101% for all of the metal ions investigated. The proposed method was validated by analyses of two certified reference materials (NIST SRM 2711 Montana soil and HPS Certified Waste Water Trace Metals Lot #D532205). It was also successfully applied to seawater and dialysis solution samples. The detection limits (n = 25, 3s) were in the range of 0.01-2.44 microg l(-1) for the studied elements and the relative standard deviations were < or =6%, which indicated that this method could fully satisfy the requirements for analysis of such samples as seawater and dialysis solution having high salt contents.     

Trace measurement of lead and cadmium ions in wastewater samples using a novel dithizone immobilized metal–organic framework-based μ-dispersive solid-phase extraction

A low-cost, reliable, easy-to-perform, sensitive and environmentally friendly metal–organic framework (MOF)-based μ-dispersivesolid-phase extraction (μ-dSPE) method for extraction and graphite furnace atomic absorption spectrometry (GF-AAS) determination of lead and cadmium ions in several wastewater samples was successfully developed. Initially, a zinc-based MOF nanosorbent was prepared, immobilized with appropriate complexing agent dithizone (DTZ), characterized and eventually applied for the simultaneous extraction of the target ions. In practice, the application of the DTZ-based MOF nanosorbent led to improvements in the extraction efficiency. After the extraction of the target ions, the desorption process, which was facilitated with vigorous agitation, was performed by applying a small amount of a desorption solvent (inorganic acid, HNO₃). In the next step, concentrations of the desorbed heavy metal ions were measured using GF-AAS. The parameters influencing the adsorption and desorption efficiencies were thoroughly evaluated followed by the establishment of optimal conditions. Under the optimum conditions, the calibration curves for respective Pb(II) and Cd(II) ions were linear over the concentration ranges 0.5–5.0 and 0.05–2.0 μg l⁻¹. Relative recovery tests on spiked wastewater samples were performed with the results varying between 96% and 103%, whilst the analogous precisions were located in the range 1.8–3.1%. Finally, the μ-dSPE method in conjunction with GF-AAS was demonstrated to be fast, sensitive and cost-effective, and could be potentially used in environmental laboratories for the surveillance of lead and cadmium ions in various wastewater samples.