Ultra-Trace Determination of NEPTUNIUM-237 and Plutonium Isotopes in Urine Samples by Compact Accelerator Mass Spectrometry (original) (raw)
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Journal of Analytical Atomic Spectrometry, 2012
Accelerator mass spectrometry (AMS) is a very sensitive and robust technique for analysis of long-lived radionuclides. Employment of the AMS technique can reduce the demands on sample preparation chemistry, due to its high rejection of interferences and low susceptibility to sample matrix. This is particularly of interest for ultra-trace determination of 239 Pu in bioassay and environmental samples, as other mass spectrometric methods such as inductively coupled plasma mass spectrometry (ICP-MS) can suffer from isobaric mass interferences by the presence of uranium in the sample. A rapid sample preparation method for analysis of Pu at femtogram levels in large volume urine samples is described.
Analytical Chemistry, 2013
An analytical method was developed for simultaneous determination of ultratrace level plutonium (Pu) and neptunium (Np) using iron hydroxide coprecipitation in combination with automated sequential injection extraction chromatography separation and accelerator mass spectrometry (AMS) measurement. Several experimental parameters affecting the analytical performance were investigated and compared including sample preboiling operation, aging time, amount of coprecipitating reagent, reagent for pH adjustment, sedimentation time, and organic matter decomposition approach. The overall analytical results show that preboiling and aging are important for obtaining high chemical yields for both Pu and Np, which is possibly related to the aggregation and adsorption behavior of organic substances contained in urine. Although the optimal condition for Np and Pu simultaneous determination requires 5-day aging time, an immediate coprecipitation without preboiling and aging could also provide fairly satisfactory chemical yields for both Np and Pu (50−60%) with high sample throughput (4 h/sample). Within the developed method, 242 Pu was exploited as chemical yield tracer for both Pu and Np isotopes. 242 Pu was also used as a spike in the AMS measurement for quantification of 239 Pu and 237 Np concentrations. The results show that, under the optimal experimental condition, the chemical yields of 237 Np and 242 Pu are nearly identical, indicating the high feasibility of 242 Pu as a nonisotopic tracer for 237 Np determination in real urine samples. The analytical method was validated by analysis of a number of urine samples spiked with different levels of 237 Np and 239 Pu. The measured values of 237 Np and 239 Pu by AMS exhibit good agreement (R 2 ≥ 0.955) with the spiked ones confirming the reliability of the proposed method.
Journal of Radioanalytical and Nuclear Chemistry, 2010
Bioassay technique is used for the estimation of actinides present in the body based on their excretion rate through body fluids. For occupational radiation workers urine assay is the preferred method for monitoring of chronic internal exposure. Determination of low concentrations of actinides such as plutonium, americium and uranium at low level of mBq in urine by alpha spectrometry requires pre-concentration of large volumes of urine. This paper deals with standardization of analytical method for the determination of Pu-isotopes in urine samples using anion exchange resin and 236Pu tracer for radiochemical recovery. The method involves oxidation of urine followed by co-precipitation of plutonium along with calcium phosphate. Separation of Pu was carried out by Amberlite, IRA-400, anion exchange resin. Pu-fraction was electrodeposited and activity estimated using tracer recovery by alpha spectrometer. Twenty routine urine samples of radiation workers were analyzed and consistent radiochemical tracer recovery was obtained in the range 74–96% with a mean and standard deviation of 85 and 6% respectively.
Accelerator mass spectrometry of actinides
Journal of Radioanalytical and Nuclear Chemistry, 2005
Accelerator mass spectrometry (AMS) is a sensitive and robust technique typically applied to the quantification of long-lived radioisotopes in samples too small to be decay-counted. AMS is characterized by a high rejection of interferences and a low susceptibility to matrix components, which reduce the demands on sample preparation chemistry. At Lawrence Livermore National Laboratory (LLNL) Center for Accelerator Mass Spectrometry (CAMS), we have developed an AMS capability for the measurement of actinide concentrations and isotopic ratios. To date, this capability has been primarily devoted to the measurement of 239 Pu and 240 Pu in bioassay and environmental samples including soils, sediments, waters, and human urine. For these analyses, a known amount of 242 Pu is added to the samples as a reference isotope for normalization. Measurements of standard and intercomparison samples have shown that quantification is accurate and precise from at least 10 6 to 10 11 atoms/sample. Recently, the ratios of 240 Pu, 241 Pu, 242 Pu, and 244 Pu to intrinsic 239 Pu have been successfully measured in soil samples from nuclear test sites. In addition, initial measurements of U and Np isotopes have yielded results consistent with the Pu measurements with respect to sensitivity, accuracy, precision, and linear range.
Perspectives of uranium and plutonium analysis in urine samples by secondary ion mass spectrometry
Journal of Radioanalytical and Nuclear Chemistry, 1997
Secondary ion mass spectrometry (SIMS) is a well-established technique that permits rapid detection of stable and radioactive nuclides. Its resolving mass power provides an efficient analytical method and, in palticular, it makes possible accurate isotopic ratio determination. Tests were carried out to evaluate the performance of this technique for the assessment of trace concentrations of uranium and plutonium in mine samples prepared in thin sources. Special attention has been paid to the preparation of the Specimens which represents a critical step for the employment of this technique due to the erosion process used by SIMS. Fixation cs the matrix in Polypyrrole fdms have been proved to be suitable. Present results show that concentrations in the order of 10 -10 g. 1 -I of 238U (10 -6 Bq-1-1) and 10 -11 g. 1-1 of 239pu (10 -2 Bq. 1-1) can be rapidly measured.
Czechoslovak Journal of Physics, 2006
Measurement of plutonium isotopes in vivo is not feasible for radiation protection purposes. Considering the slow rate of plutonium excretion, the respect to annual dose limits, whenever risk of plutonium internal contamination occurs, implies the need of a monitoring programme based on very sensitive bioassay, i.e., measurement of plutonium content in samples of urine or feces, characterized by a very low minimum detectable activity. Alpha spectrometry is the most common measurement method applied in this field. The applicability of this method strictly depends on the procedure adopted for the sample radiochemical preparation preceding the real spectrometric counting and, particularly, on the element chemical recovery that is one of the parameters that mostly influence the minimum detectable activity achievable by the analysis. The aim of the present work is to compare the performances of four of the most widely adopted radiochemical procedures making use of different separation methods for the determination of plutonium in urine samples via alpha spectrometry.
Plutonium measurements by accelerator mass spectrometry at LLNL
Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, 2000
Mass spectrometric methods provide sensitive, routine, and cost-effective analyses of longlived radionuclides. Here we report on the status of work at Lawrence Livermore National Laboratory (LLNL) to develop a capability for actinide measurements by accelerator mass spectrometry (AMS) to take advantage of the high potential of AMS for rejection of interferences. This work demonstrates that the LLNL AMS spectrometer is well-suited for providing high sensitivity, robust, high throughput measurements of plutonium concentrations and isotope ratios. Present backgrounds are ~2×10 7 atoms per sample for environmental samples prepared using standard alpha spectrometry protocols. Recent measurements of 239+240 Pu and 241 Pu activities and 240 Pu/ 239 Pu isotope ratios in IAEA reference materials agree well with IAEA reference values and with alpha spectrometry and recently published ICP-MS results. Ongoing upgrades of the AMS spectrometer are expected to reduce backgrounds below 1×10 6 atoms per sample while allowing simplifications of the sample preparation chemistry. These simplifications will lead to lower per-sample costs, higher throughput, faster turn around and, ultimately, to larger and more robust data sets.
Journal of Analytical Atomic Spectrometry, 2004
The Centers for Disease Control and Prevention has a mission to protect and promote public health, which includes investigation of environmental exposures to toxic substances that could threaten health. Plutonium is an environmentally available substance that is chemically and radiologically toxic and represents a potential health threat from excessive exposure. Inductively coupled plasma mass spectrometry (ICP-MS) is a sensitive method for assessing environmental or unintentional exposure to these and other actinides. We report here a magnetic sector instrument method in which a desolvating introduction system is used to provide rapid, sensitive emergency response analysis for 239 Pu in only 1 mL of urine without digestion or coprecipitation. 239 Pu was separated from U and interfering urine organic substances by solid phase extraction. The within run limit of detection (LOD) was 0.16 fg mL 21 for 1 mL of urine even though originally spiked to 1018 ng L 21 of depleted U. A more rigorous LOD of 1.4 fg mL 21 239 Pu was based on 3 ''total'' standard deviations in the presence of the same U concentration. At below 10 6 atoms of 239 Pu detectable in 1 mL of urine, this method is sufficiently sensitive for elevated emergency exposure assessment with high throughput. The precision for 10 duplicate samples was within 3.7% relative ''total'' standard deviation (RSD, within and between run) for a 9.96 fg mL 21 239 Pu-spiked urine sample and within 2.2% for a 99.6 fg mL 21 239 Pu-spiked urine sample. The method was demonstrated to be accurate within 2.6% of the Los Alamos National Laboratories target value at 99.6 fg mL 21 , to within 1.0% of target value at 9.96 fg mL 21 and within 1.2% at 0.996 fg mL 21 , just below the method LOD.