Method For Determination Of Uranium Research Articles

A Rapid and Simple Method for Determination of Uranium in Gattar Area by ICP-OES

This experiment was carried out to determine Uranium in a geological samples collected from Gattar area, North Eastern Desert of Egypt which examined by scanning electron microscope (EDX) to be characterized by hematization, silicification, muscovitization and fluoritization which are the most dominant alteration associated with the uranium mineralization. Inductively coupled plasma optical emission spectrometry (ICP-OES) was used for this study. Two methods of digestion of samples were used in the experiment and four emission lines were selected for uranium to choose the more sensitive one. The physical parameter conditions were adjusted by using standard solution of uranium to be 1200 W for RF power current, 35 psi for nebulizer gas pressure and 18 L/min for coolant gas pressure. The interference effect of some elements was studied on the selected line and showed that, the determination of uranium by ICP-OES is affected seriously by iron, aluminum, calcium, thorium and rare earth elements. The results of uranium determination at 303.199 nm with precipitation method were compared with the results from XRF method which shown acceptable accuracy and low time consuming other method.

An innovative spectrophotometric method for determination of uranium and thorium using 3-aminomethylalizarn-N-N diacetic acid in some geological samples

3-aminomethylalizarn-N-N diacetic acid chromogenic dye (AMADA) was used for the first time in uranium and thorium spectrophotometric estimation with accurate and sensitive result, their complexes having a maximum absorbance at 575 nm for U and at 510 nm for Th. This system allows uranium and thorium content to be calculated with a detection limit (LOD) of 0.16 µg L−1 and 0.14 µg L−1, respectively. The first-derivative spectra and EDTA were investigated to eliminate interference and provide selective estimation of uranium and thorium in presence of each other. This new spectrophotometric method was applied for the determination of U(VI) and Th(IV) in the standard reference materials (granite and Syenite) and some cataclastic rock samples with accurate results.

Cloud point extractive spectrophotometric method for determination of uranium in raffinate streams during spent nuclear fuel reprocessing

A cloud point extractive spectrophotometric method was developed for the determination of uranium in raffinate streams. Uranium was extracted to a tri n-octyl phosphine oxide in o-Xylene from raffinate. Uranium present in organic phase was analyzed by spectrophotometry after cloud point extraction of U-PAR (4-(2-Pyridylazo) resorcinol) complex to cetyl trimethyl ammonium bromide—Triton-X-100 medium. The molar absorption coefficient for uranium complex was found to be 2.2 × 104 l mol−1 cm−1. The relative standard deviation for the determination of uranium was found to be 3.9% and with a minimum detection limit of 2 µg uranium per aliquot.

A novel method for the determination of uranium and free acidity in nuclear fuel process samples by extraction spectrophotometry

Abstract A novel and useful extraction spectrophotometric method for the rapid determination of uranium and free acidity in nuclear fuel process samples using the reagent, 2,3-dihydroxynaphthalene as an extractant as well as color forming agent is described. Uranium at milligram level forms a yellowish- orange anionic complex with the ligand, 2,3-dihydroxynaphthalene over a pH range, 10–12. This anionic complex is easily extracted into ethylacetate as an ion-pair complex with cetyltrimethylammonium cation (CTA+). The absorbance of the ion-pair complex in ethylacetate is measured at 390 nm. The molar absorptivity and Sandell’s sensitivity of the system being 5.0×103 L·mol−1 cm−1 and 0.047 μg cm−2, respectively at 390 nm. This very reagent (2,3-dihydroxynaphthalene) also forms a yellowish-orange nitro product with free nitric acid (HNO3) in the presence of concentrated sulfuric acid. This nitro- product is easily extracted into the same solvent (ethylacetate) and absorbs maximum at 380 nm. The molar absorptivity (ε) and Sandell’s sensitivity of the system being 2.4×103 L·mol−1 cm−1 and 0.027 μg cm−2, respectively. By using the single chromophoric agent (2,3-dihydroxynaphthalene), both uranium and free acidity can be easily and reliably determined separately in the process solution. The relative standard deviations (RSD) are in the range, 0.5–2.0% and 1.5–2.0%, respectively for uranium and free nitric acid determinations. The method has been applied to nuclear fuel process solutions, and the results obtained have been found to be favorably comparable with those obtained from standard methods.

Moving window partial least squares after orthogonal signal correction as a coupling method for determination of uranium and thorium by ultrasound‐assisted emulsification microextraction

AbstractThis study, a fast, simple, and efficient ultrasound‐assisted emulsification microextraction coupled with orthogonal signal correction‐moving window partial least squares (OSC‐MWPLS) was successfully used to preconcentration and simultaneous spectrophotometric determination of uranium and thorium in water samples. Response surface methodology based on a Box‐Behnken design was used to optimize the extraction conditions. The analysis of variance and some statistical tests such as lack‐of‐fit and coefficient of determination (R2) showed good fit of the experimental data with the second‐order polynomial model. Under the optimum conditions, the calibration graphs were linear in the range of 10.0 to 230.0 and 10.0 to 250.0 ng mL−1 with detection limits of 3.11 and 3.56 ng mL−1 (3Sb/m) for uranium and thorium, respectively. The preconcentration factor of this method for uranium and thorium reached 192. Repeatability (intra‐day) and reproducibility (inter‐day) were obtained 1.23% and 2.18% for uranium and 1.34% and 1.95% for thorium, respectively. The OSC was used for preprocessing of data matrices, and also MWPLS regression has been proposed for the selection of informative spectral intervals. In this paper, ultrasound‐assisted emulsification microextraction coupled with OSC‐MWPLS method was presented for the first time. The root mean square error of prediction for uranium and thorium with PLS, OSC‐PLS, and OSC‐MWPLS were 11.755, 10.335 and 5.301, 5.399 and 0.974, 0.986 ng mL−1, respectively. The results indicated that practical and environmentally friendly proposed method could be successfully used to the simultaneous determination of uranium and thorium in different environmental water samples.

Lab-on-paper optical sensor for smartphone-based quantitative estimation of uranyl ions

We report here, for the first time, a smartphone-based lab-on-paper method for determination of uranium in ores. The method is based on the reaction with arsenazo-III on a filter-paper strip. The intensity of the green color was determined by a smartphone. The calibration curve is linear up to at least 60 μg mL−1 of uranium with LOD and LOQ values of 0.66 and 2.21 μg mL−1, respectively. The proposed method was applied for the analysis of spiked water samples and real Egyptian ore samples with recoveries ranging from 97.3 to 104.7%. The results are in agreement with the reported reference titrimetric method.

Total reflection X-ray spectroscopy as a rapid analytical method for uranium determination in drainage water

ABSTRACTUranium concentrations in drainage water are typically determined by α-spectrometry. However, due to the low specific radioactivity of uranium, the evaporation of large volumes of drainage water, followed by several hours of measurements, is required. Thus, the development of a rapid and simple detection method for uranium in drainage water would enhance the operation efficiency of radiation control workers. We herein propose a novel methodology based on total reflection X-ray fluorescence (TXRF) for the measurement of uranium in contaminated water. TXRF is a particularly desirable method for the rapid and simple evaluation of uranium in contaminated water, as chemical pretreatment of the sample solution is not necessary, measurement times are typically several seconds, and the required sample volume is low. We herein employed sample solutions containing several different concentrations of uranyl acetate with yttrium as an internal standard. The solutions were placed onto sample holders, and were dried prior to TXRF measurements. The relative intensity, otherwise defined as the net intensity ratio of the Lα peak of uranium to the Kα peak of yttrium, was directly proportional to the uranium concentration. Using this method, a TXRF detection limit for uranium in contaminated water of 0.30 µg/g was achieved.

Micellar Electrokinetic Chromatographic Separation/Determination of Uranium, Iron, Copper and Nickel from Environmental Ore Samples Using Bis(salicylaldehyde)meso-stilbenediimine as Chelating Reagent

Uranium is well known for its use as nuclear fuel and is increasingly being used for power generation. The sensitive methods for determination of uranium are based on inductively coupled plasma mass spectrometry (ICP-MS), inductively coupled plasma atomic emission spectrometry (ICP-AES), X-ray fluorescence spectrometry, activation analysis, high performance liquid chromatography (HPLC) and capillary electrophoresis (CE). High sensitivity and selectivity for the determination of uranium is reported using HPLC with appropriate complexing reagents. For post-column derivatization complexing reagents commonly used are arsenazo III and 4-(2-pyridyl) resorcinol. For pre-column derivatization, different hydrazones, α-hydroxyisobutyric acid and tetradentate Schiff bases have been reported. The analytical procedures based on ICP-MS and ICP-AES are sensitive for multi-elemental analysis, but involve expensive equipment with high running cost. Capillary electrophoresis (CE) is taking place for the analysis of metal ions due to its high resolution power, low solvent consumption and short analysis time. Capillary electrophoresis separations are based on different modes Micellar Electrokinetic Chromatographic Separation/Determination of Uranium, Iron, Copper and Nickel from Environmental Ore Samples Using Bis(salicylaldehyde)meso-stilbenediimine as Chelating Reagent

Simple and Rapid Spectrophotometric Method for Determination of Uranium (VI) in Low Grade Uranium Ores Using Arsenazo (III)

A simple and highly selective non-extractive spectrophotometric method is presented for the rapid determination of uranium in low grade uranium ores using arsenazo (III). The method is based on the complex formation of uranium (VI) with Arsenazo (III) at pH 2.0 ± 0.1 which showed maximum absorption at 651 m. Uranium concentration of 10 μg g-1 with a molar absorptivity of 4.45×104 mol-1×cm-1 at 296 ± 2 K obeyed Beer’s law. Interferences caused by various metallic ions,such as Mn, Fe, Zn, Mo, Cr, Cu, Co, Ni, Zr, Pb, Al and Na were effectively masked by diethylenetriaminepenta-acetic acid (DTPA) and tartaric acid. The proposed technique has been effectively applied to the determination of low levels of uranium in uranium leach liquors. The accuracy of the current method was checked by comparison with the results obtained by inductively coupled plasma-optical emission spectroscopy (ICP-OES). Приведено простий і високоселективний спектрофотометричний метод для швидкого визначення урану в низькосортних уранових рудах з використанням арсеназо (III). Метод базується на утворенні комплексу урану (VI) з арсеназо (III) за рН = 2,0 ± 0,1 з максимумом поглинання при 651 нм. Концентрації урану порядку 10 мг×г-1 і молярний коефіцієнт поглинання 4,45×104 моль-1×см-1 при 296 ± 2 К підкоряються закону Бера. Вплив різних йонів металів, таких як Mn, Fe, Zn, Mo, Cr, Cu, Co, Ni, Zr, Pb, Al і Na ефективно нейтралізується діетилентриамінопентаоцтовою і винної кислотами. Запропонований метод був ефективно використаний для визначення низьких концентрацій урану в лугах після вилуговування. Точність запропонованого методу була перевірена порівнянням з результатами, отриманими за допомогою індуктивно-зв‘язаної плазмо-оптичної емісійної спектроскопії.

Improvement of the potentiometric method for uranium determination in solutions

Redox potentiometric titration of small amounts of U in mixed phosphoric-sulfuric acid systems with an automatic titrator was studied. The U determination accuracy is strongly affected by the aqueous phase composition and kind of titrant. In determination of 0.1–0.2 mg of U in mixed phosphoric-sulfuric acid solutions containing 6 M H3PO4 and 1.25 M H2SO4, the titrant efficiency decreases in the order NH4VO3 > KMnO4 > Ce(SO4)2 > K2Cr2O7. In 2 M H2SO4, the use of KMnO4 as titrant allows determination of 0.02–0.1 mg of U with the uncertainty within 10%.

Determination of Uranium in Seawater Samples by Liquid Chromatography using Mandelic Acid as a Complexing Agent

The determination of uranium at different stages of the recovery process as well as in seawater is important in its recovery study. A previous study developed a high-performance liquid chromatography (HPLC) method for uranium determination in seawater using α-hydroxy isobutyric acid as a chelating agent. However, this method causes turbidity in process samples containing high amounts of iron, resulting in the clogging of the HPLC column. In the present work, use of mandelic acid as a chelating agent for uranium has been explored. Elution conditions were optimized for the separation of iron [Fe(III)] and uranium [U(VI)] by studying the effect of an ion interaction reagent, the concentration of mandelic acid, and methanol content in the mobile phase. Different parameters were optimized to develop off- line pre-concentration of uranyl-mandelate on the reversed stationary phase. The method offers quantitative recovery of uranium and linearity in the U(VI) concentration range of 0.5 ppb to 500 ppb and can be used for the determination of U(VI) in process samples with Fe/U amount ratios up to 3,000. The method has been successfully used for the determination of U(VI) in seawater samples and process samples. The developed methodology was validated by comparing the results with those of isotope dilution-thermal ionization mass spectrometry.

An EDXRF method for determination of uranium and thorium in AHWR fuel after dissolution

AbstractA fast energy dispersive x‐ray fluorescence (EDXRF) method requiring only microgram amounts of analytes, i.e. uranium (U) and thorium (Th), in their mixtures in solution form is described. Calibration solutions and samples covering the fuel composition range (0–5% of U in U + Th) of advanced heavy water reactor (AHWR) were prepared by mixing uranium and thorium solutions. A known fixed amount of internal standard yttrium (Y) was added to these solutions. EDXRF spectra of calibration solutions and samples were measured by taking 20 µl aliquots on 30 mm diameter filter papers, after drying, using a Rh target tube operated at 40 kV and 500 µA. Calibration plots were made by plotting U/Y, U/Th and Th/Y amount ratios against the respective intensity ratios of Th Lα, U Lα and Y Kα. In the first set, U was determined using Y as an internal standard, and for Th determination, U, thus determined, was used as an internal standard since the amounts of Th and Y were kept constant in the calibration solutions and samples.In the second set, both U and Th were varied and determined using Y as internal standard. The results of U and Th determinations showed a precision of about 3% (1s) and the results deviated from the expected values by <3% in most of the cases. This approach has an advantage that it requires only microgram amounts of sample, thus mitigating radiation hazards associated with radioactive samples as well as the amount of radioactive analytical waste generated is quite less. Copyright © 2009 John Wiley & Sons, Ltd.

Fast determination of uranium and radium in waters of variable composition

The effects of uranium and its progeny radium are known to be harmful and their measurements in drinking water are necessary for careful monitoring. Fast and accurate methods for determination of uranium and radium in water samples with various salinity and activities concentrations have been developed. High Resolution Inductively Coupled Plasma Mass Spectrometry is used for direct measurement of uranium. Calibration is performed with 238U standards and 209Bi is used as internal standard to correct the matrix effects and plasma instability. The radium is determined by photon electron rejected alpha liquid spectrometry after a chemical separation procedure that includes co-precipitation of radium with barium sulphate, transformation of the sulphate to carbonate and extraction of radium in the scintillation cocktail. The minimal detectable activities of 3.5×10−8 Bq kg−1 for uranium and 2.3×10−4 Bq kg−1 for radium are obtained.

Use of the Eurachem guide on method validation for determination of uranium in environmental samples

Three analytical methods for determination of uranium in environmental samples by a fluorescence technique have been validated and compared in accordance with the Eurachem Guide on method validation. The first method depends on uranium separation from iron using the mercury anode technique; in the other two methods uranium is separated from iron on an anion exchange column by use of either a solution of hydrochloric acid containing ascorbic acid and hydrazine hydrate or a dilute sulfuric acid solution. Detection limits, repeatability, reproducibility, and recovery coefficient were the main validation characteristics. The results showed that better statistical values can be achieved by using the third method. Control charts for in-house control samples and international intercomparison samples have also shown that the third method is more statistically stable with time. In addition, uncertainties of measurement were estimated and compared for the three methods. It was found that the Eurachem Guide and comparison of quality statistical validation data can be good tools for selection of the appropriate method for an application.

Uranium bioassay--beyond urinalysis.

Assessment of occupational or environmental exposure to uranium compounds is largely based on urinalysis. However, urine samples generally reflect either recent exposure (within a few days after an incident) or chronic exposure and, furthermore, diurnal fluctuations in "spot samples" make it difficult to estimate the extent of the internal dose received. Thus, if urine samples are not collected within a relatively short time after accidental exposure or if the samples are not representative due to collection logistics, internal dosimetry calculations based only on urinalysis may be misleading. With the advent of efficient and sensitive methods for determination of uranium in hair and nails, some of these drawbacks may be overcome. It is proposed that with little additional cost, determination of the uranium in hair may yield better insights for internal dosimetry of uranium exposure.

Flow injection method for determination of uranium in urine and serum by inductively coupled plasma mass spectrometry

The uranium concentration in urine of a population that is not occupationally exposed to uranium compounds is in the range 1–40 ng l −1 with a median around 10 ng l −1. This is analytically challenging for routine analysis because at such low levels it is difficult to prevent contamination during sample preparation. The method presented here is based on sample introduction via a flow injection analysis system and inductively coupled plasma mass spectrometric detection, and requires virtually no sample preparation, except for acidification of the urine sample with a few drops of HNO 3 The analysis is fully automated and fast with an analysis time of 60 s per sample. The lower limit of detection is 1.5ng l −1. Memory and matrix effects may be decreased by adding 1 g l −1 of a surfactant (Triton-X 100) to the carrier stream. The validity of the results is demonstrated through measurement of standard reference materials, standard dilution experiments and, at higher concentrations, by comparison with results obtained by an independent method based on laser induced fluorescence.

Yields and losses at each step in preparing uranium and thorium samples for alpha spectrometry

The percentages of activity lost at each step in a common method for determination of uranium and thorium in aqueous environmental samples were investigated. The method studied involves the concentration of the sample (in which the actinides are co-precipitated with an iron hydroxide carrier), extraction by di-isopropylether, separation of uranium and thorium using an ion-exchange procedure, and, finally, electrodeposition using sulphuric acid as electrolyte. The results suggest that the main optimization of the total yield must be done at the concentration step, because around 50% of initial activity is lost here.

Extraction-spectrophotometric determination of uranium(VI) with PAR and N-octylacetamide

A new and simple method for selective spectrophotometric determination of uranium(VI) with 4-(2-pyridylazo)resorcinol (PAR) and N-octylacetamide into benzene over pH 7.0–9.0 is described. The molar absorptivity of the complex with 9 different amides is in the range of (0.40–3.2)·104 1·mol−1·cm−1 at the absorption maximum. Out of these, the most sensitive compound N-octylacetamide (OAA) was chosen for detailed studies in the present investigation. The detection limit of the method is 0.008 μg U·ml−1. The system obeys Beer's law in the range of 0–5 μg U·ml−1. The method is free from interferences of most of the common metal ions except vanadium(V) and copper(II), which are masked by proper masking agents. The composition of the complex is determined by curve-fitting method. The method has been applied for the recovery of the metal from rock samples and synthetic mixtures.

An Optimised Method for Simultaneous Determination of Uranium and Thorium in Urine and Faeces Samples

A fast and simple procedure for the simultaneous determination of alpha-emitting isotopes of thorium and uranium in human urine and faetal samples has been developed. The chemical treatment used to produce samples on discs suitable for counting in an alpha spectrometer is outlined. For both isotopes the lower limit of detection is 10 −3 Bq per litre of urine or per gram of faeces ash, and the chemical recovery is 85±3%

Simultaneous determination of U and Th by delayed fission neutron technique based on neutron generator

A method for simultaneous determination of uranium and thorium based on the deviation of their fission cross-section curves has been developed. Using a D-T neutron generator two different neutron spectra were produced with and without moderator around the target. The detection limits were found to be 0.044 mg and 0.25 mg in the presence of a moderator, while for fast neutrons 0.017 mg and 0.037 mg for uranium and thorium, respectively.