Critical comparison of radiometric and mass spectrometric methods for the determination of radionuclides in environmental, biological and nuclear waste samples

Interlaboratory Comparison: Determination of radionuclides in environmental samples in Taiwan

Radionuclides in the environment occur naturally (primordial and cosmogenic) and are produced by human activities (anthropogenic). This study examines the capabilities of laboratories in Taiwan for measuring radionuclides in environmental samples. We compared the laboratories' ability to determine the activity of natural and anthropogenic radionuclides, such as tritium (3H), potassium-40 (40K), strontium-90 (90Sr), cesium-137 (137Cs), thallium-208 (208Tl), bismuth-214 (214Bi), actinium-228 (228Ac), gross beta, and gross uranium (234U, 235U, 238U). The reported data were evaluated using statistical methods like zeta scores and visual representations like PomPlots. The results indicate that the measurement capabilities in Taiwan are still up-to-date and the measurements provided by these laboratories in recent years can be considered trustworthy and reliable.

An Evaluation of Actinide Reactivity with CO2, O2, and O2/He Gases using Inductively Coupled Plasma Tandem Mass Spectrometry: Application to Simultaneous Measurement of 241Am/241Pu Ratios in Unseparated Complex Matrices

Accurate actinide measurements are critical within the field of nuclear science. Traditional methods for actinide quantification require time-consuming sample processing prior to analysis. There is a need for rapid analytical techniques that still maintain a high degree of accuracy. In this work, actinide reactivity was assessed for multiple oxygen-containing reaction gases using quadrupole inductively coupled plasma tandem mass spectrometry (Q-ICP-MS/MS) to evaluate actinide analysis in complex sample matrices without analyte-matrix separation. A novel method was developed to measure 241Am/241Pu in complex sample matrices using an O2/He reaction gas with no matrix removal or analyte preconcentration. This inline method reduces matrix-derived polyatomic interferences that complicate traditional ICP-MS analyses by mass-shifting to 241Am16O+ and 241Pu16O2+, allowing Am and Pu to be mass separated for simultaneous analysis. While mass shifting is efficient, a small portion of Am+ (<1.3%) and Pu+ (<1.4%) react to form AmO2+ and PuO+, respectively. Therefore, a mass balance approach was used, in combination with reactivity determined from 242Pu and 243Am standard solutions, to correct for residual 241PuO+ and 241AmO2+. The method was validated by measuring 241Am/241Pu in Pu isotope standards CRM-136 and CRM-137 (separated in March/April 1970 and February 2022, respectively) in both neat solutions and complex matrices containing diluted soil (NIST SRM 2711a, > 1000 μg·g-1). Method detection limits of 15.9 and 9.6 fg·g-1 were determined for 241Am and 241Pu, respectively, and 241Am/241Pu ratios were measured with accuracies within <3.5%. This work presents the first direct analysis of 241Am/241Pu in unseparated complex matrices, advancing the capabilities for rapid actinide measurements.

Flow Electrolysis on Anodized Carbon Fibers for Pu Separation and Analysis

The analysis of Pu isotopes with radiometric or mass spectrometry techniques requires prior chemical separation to overcome interferences from other actinides and to remove matrix components. These separations are usually carried out using extraction or ion exchange chromatography. In this work, flow electrolytic separation on anodized carbon fibers is explored as a new alternative approach for the separation and analysis of Pu isotopes by means of radiometric methods. A high-surface-area carbon fiber felt electrode was anodized and used for flow electrolytic accumulation and release of Pu. Characterization of the anodized carbon fiber felt was carried out using X-ray photoelectron and infrared spectroscopy. The conditions needed for the retention of Pu during electrolysis were investigated, optimized, and used to develop a method for the measurement of 238Pu or 239,240Pu by α-spectrometry. This method was evaluated with digested solid samples (i.e., wipe test, ceramics, and sludge) and compared with traditional chromatographic separation approaches. It was found that oxygen-containing functional groups are introduced on the carbon fiber surface upon its anodization. This allows the accumulation of Pu(IV), which is produced by adjusting the electrode potential and can be released by electroreduction to Pu(III), whereas other actinides (e.g., U, Am, and Cm) as well as matrix components are not retained. This provides a fast, single-step separation of Pu, free of impurities from reagents or resins, which may be detrimental to the preparation of α-sources. The successful measurement of Pu isotopes confirmed the reliability and good tolerance of this approach for highly complex matrices.

Metal-organic frameworks as advanced platforms for radionuclide detection

The development of nuclear energy has significantly increased the prevalence of artificial radionuclides, mainly generated through nuclear fission processes, alongside naturally occurring radionuclides. These radionuclides, encompassing a wide array of elements, including 3H, 85Kr, 90Sr, 99Tc, 129/131I, 137Cs, 222Rn, 232Th, and 235/238U, exist in diverse chemical forms such as gases, ions, and molecular species, posing substantial risks to human health and environmental safety. Consequently, the precise detection and selective separation of these radionuclides are of paramount importance for the timely identification and mitigation of associated hazards. This review explores the application of metal-organic frameworks (MOFs) as advanced platforms for radionuclide detection, utilizing their structural tunability and versatile functionality. The discussion is systematically organized based on the chemical forms of radionuclides, categorizing them into gaseous, cationic, and anionic species. Key detection mechanisms employed by MOFs, including fluorescence sensing (via quenching, enhancement, and fluorochromism), scintillation techniques, colorimetric sensing, electrochemical sensing, and so on, are thoroughly examined. These approaches are analysed to elucidate their principles, practical implementations, and limitations.

Insulin like growth factor binding protein 7 activate JNK/ERK signaling to aggravate uranium-induced renal cell cytotoxicity

Acute kidney injury (AKI) can occur primarily by exposing kidneys to uranium (U). Insulin-like growth factor binding protein 7 (IGFBP7) can regulate sepsis-induced AKI and epithelial-mesenchymal transition through ERK1/2 signaling. In vitro, the IGFBP7's role and mechanism of action in uranium-induced NRK-52E cells, however, remains unknown. To evaluate the effect of U exposure on kidneys, rat kidney proximal cell line NRK-52E was treated with different concentrations (200, 400, and 800 µmol/L) of it. Subsequently, three siRNAs targeting IGFBP7 were transfected with the HiPerFect reagent. The role of the JNK/ERK signaling pathway in uranium-induced kidney cytotoxicity was examined by a series of cell function experiments, including CCK-8 assay, TUNEL staining, RT-qPCR, Western blot, and flow cytometry analysis. Uranium inhibited NRK-52E cell viability and enhanced IGFBP7 expression in a dose-dependent manner. Silencing of IGFBP7 promoted cell cycle progression and inhibited cell apoptosis of uranium-treated cells. Mechanistically, silencing of IGFBP7 inhibited the uranium-activated JNK/ERK signaling pathway. The ERK1/2 signaling inhibitor PD98059 suppressed the IGFBP7-activated JNK/ERK signaling pathway. Furthermore, knockdown of IGFBP7 exerted a similar effect with PD98059 on uranium-induced NRK-52E cell cycle arrest and apoptosis. Silencing IGFBP7 inhibited the JNK/ERK signaling pathway to attenuate uranium-induced cytotoxicity and necrosis of NRK-52E cells.

Ultra-fast, selective and pseudo-quantitative analysis of 99Tc in nuclear waste for screening purposes

Controlling radioactivity is essential in various fields, such as the decommissioning of nuclear power plants and nuclear medicine. In some cases, a full characterization of samples is not required; instead, a screening analysis that provides an overall indication of the activity present can be sufficient to determine if a sample is radioactive. This article introduces a new system called PSkits designed specifically for ultra-fast and selective screening detection of 99Tc. PSkits consist of a plastic scintillation layer attached to the bottom of a scintillation vial, coated with aliquat·336® as a selective extractant. In this study, the preparation of PSkits was optimized by adjusting the proportions of crosslinker, porogen, and the type of vial used. The analysis method was developed, and the selectivity against common interferences was tested by optimizing the rinsing media. Finally, PSkits were validated by analysing simulated nuclear waste samples and urine spiked samples, achieving satisfactory results with quantification errors below 50 %, demonstrating their effectiveness for the intended purpose.

Radiometric approaches with carbon-14-labeled molecules for determining herbicide fate in plant systems

Weeds cause economic losses in cropping systems, leading to the use of 1.7 million tons of herbicides worldwide for weed control annually. Once in the environment, herbicides can reach non-target organisms, causing negative impacts on the ecosystem. Herbicide retention, transport, and degradation processes determine their environmental fate and are essential to assure the safety of these molecules. Radiometric strategies using carbon-14 herbicides (14C) are suitable approaches for determining herbicide absorption, translocation, degradation, retention, and transport in soil, plants, and water. In this work, we demonstrate how 14C-herbicides can be used from different perspectives. Our work focused on herbicide-plant-environment interactions when the herbicide is applied (a) through the leaf, (b) in the soil, and (c) in the water. We also quantified the mass balance in each experiment. 14C-mesotrione foliar absorption increased with oil and adjuvant addition (5-6 % to 25-46 %), and translocation increased only with adjuvant. More than 80 % of 14C-quinclorac and 14C-indaziflam remained in the soil and cover crops species absorbed less than 20 % of the total herbicides applied. In water systems, Salvinia spp. plants removed 10-18 % of atrazine from the water. Atrazine metabolism was not influenced by the presence of the plants. The radiometric strategies used were able to quantify the fate of the herbicide in different plant systems and the mass balance varied from 70 % to 130 %. Importantly, we highlight a critical and practical view of tracking herbicides in different matrices. This technique can aid scientists to explore other pesticides as environmental contaminants.

A review of 210Pb and 210Po in moss

Among environment contaminants, 210Pb and 210Po have gained significant research attention due to their radioactive toxicity. Moss, with its exceptional adsorption capability for these radionuclides, serves as an indicator for environmental 210Pb and 210Po pollution. The paper reviews a total of 138 articles, summarizing the common methods and analytical results of 210Pb and 210Po research in moss. It elucidates the accumulation characteristics of 210Pb and 210Po in moss, discusses current research challenges, potential solutions, and future prospects in this field. Existing literature indicates limitations in common measurement techniques for 210Pb and 210Po in moss, characterized by high detection limits or lengthy sample processing. The concentration of 210Pb and 210Po within moss display substantial variations across different regions worldwide, ranging from Collapse

Key Words

• (210)Pb
• (210)Po
• Environmental contamination
• Measurement method
• Moss bioindication

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MESH Headings

• Lead Radioisotopes/analysis
• Polonium/analysis
• Bryophyta/chemistry
• Radiation Monitoring/methods

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Grants Collapse

Affiliation(s)

Chenlu Ding College of Nuclear Technology and Automation Engineering, Chengdu University of Technology, Chengdu, 610059, Sichuan, PR China
Qiang Yang College of Nuclear Technology and Automation Engineering, Chengdu University of Technology, Chengdu, 610059, Sichuan, PR China; Sichuan Cancer Hospital & Institute, Affiliated Cancer Hospital of University of Electronic Science and Technology of China, Chengdu, 611731, PR China.
Xue Zhao Chongqing Radiation Environment Supervision and Management Station, Chongqing, 400015, PR China
Lipeng Xu Sichuan Cancer Hospital & Institute, Affiliated Cancer Hospital of University of Electronic Science and Technology of China, Chengdu, 611731, PR China
Hui Tang College of Nuclear Technology and Automation Engineering, Chengdu University of Technology, Chengdu, 610059, Sichuan, PR China; Sichuan Management and Monitoring Center Station of Radioactive Environment, Chengdu, 611139, PR China
Zhengshang Liu College of Nuclear Technology and Automation Engineering, Chengdu University of Technology, Chengdu, 610059, Sichuan, PR China
Juan Zhai College of Nuclear Technology and Automation Engineering, Chengdu University of Technology, Chengdu, 610059, Sichuan, PR China
Qingxian Zhang College of Nuclear Technology and Automation Engineering, Chengdu University of Technology, Chengdu, 610059, Sichuan, PR China

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Recent progresses in analytical method development for 210Pb in environmental and biological samples

As a decay product of uranium series, 210Pb spreads widely in the nature and imposes strong radiological and chemical toxicity. It is vital to establish reliable and efficient radioanalytical methods for 210Pb determination to support environment and food radioactivity monitoring programs. This article critically reviews analytical methods developed for determining 210Pb in environmental and biological samples, especially new development in recent years. Techniques applied throughout different analytical steps including sample pretreatment, separation, purification, and detection are summarized and their pros and cons are discussed to provide a holistic overview for 210Pb environmental and biological assay.

Determination of ultra-trace level 241Am in marine sediment and seawater by combining TK200-TK221 tandem-column extraction chromatography and SF ICP-MS

Sound strategies for marine chemical monitoring call for measurement systems capable of producing comparable analytical results with demonstrated quality. This work presents the development and validation of a new analytical procedure for the determination of the 241Am mass fraction in marine sediment and seawater samples at low levels. The procedure includes a tandem-column extraction chromatography for separation of 241Am and sector field-inductively coupled plasma mass spectrometry (SF ICP-MS) for its determination. The separation is based on the application of two new extraction resins, TK200 and TK221. The acid leaching method was employed for the pre-treatment of marine sediments, while Fe(OH)3 co-precipitation was used for Am pre-concentration in seawater samples. The extraction behaviors of Am on TK221 resins in the different acidic mediums were investigated. The removal capabilities of the tandem TK200-TK221 columns for the 241Am in the presence of interfering elements including Pu, Pb, Hg, Bi, Tl, Pt, Hf, U, and Th were carefully investigated and the corresponding decontamination factors (DFs) estimated to be in the range from 104 to 106. The main interfering element Pu was efficiently removed with a DF of about 6 × 105. Matrix rare earth elements (REEs) in marine sediments were further removed by the application of TEVA resins. 241Am mass fraction was quantified by the application of external calibration and SF ICP-MS. Following the recommendations of the ISO/IEC 17025 guidelines, the validation of the analytical procedure was accomplished by executing it on the certified reference material (CRM) IAEA-385 (marine sediment) and the seawater IAEA-443 reference materials (RM). The obtained results showed that 241Am mass fractions were accurately determined in both reference samples, with excellent reproducibility (2.1 % and 7.6 %) and low LODs (0.4 fg g-1 and 0.2 fg g-1). The relative expanded uncertainties (k = 2) obtained were 17.1 % and 29.0 %, respectively. The overall analytical times for the application of the proposed procedure on the marine sediment and seawater samples were evaluated to be only about 9 h and 6.5 h, respectively. It shows great advantages for its potential applications for emergency monitoring of 241Am contamination in the marine environment.

Level, distribution and sources of Np, Pu and Am isotopes in Peter the Great Bay of Japan sea

Transuranium elements such as Np, Pu and Am, are considered to be the most important radioactive elements in view of their biological toxicity and environmental impact. Concentrations of 237Np, Pu isotopes and 241Am in two sediment cores collected from Peter the Great Bay of Japan Sea were determined using radiochemical separation combined with inductively coupled plasma mass spectrometry (ICP-MS) measurement. The 239,240Pu and 241Am concentrations in all sediment samples range from 0.01 Bq/kg to 2.02 Bq/kg and from 0.01 Bq/kg to 1.11 Bq/kg, respectively, which are comparable to reported values in the investigated area. The average atomic ratios of 240Pu/239Pu (0.20 ± 0.02 and 0.21 ± 0.01) and 241Am/239+240Pu activity ratios (3.32 ± 2.76 and 0.45 ± 0.17) in the two sediment cores indicated that the sources of Pu and Am in this area are global fallout and the Pacific Proving Grounds through the movement of prevailing ocean currents, and no measurable release of Np, Pu and Am from the local K-431 nuclear submarine incident was observed. The extremely low 237Np/239Pu atomic ratios ((2.0-2.5) × 10-4) in this area are mainly attributed to the discrepancy of their different chemical behaviors in the ocean due to the relatively higher solubility of 237Np compared to particle active plutonium isotopes. It was estimated using two end members model that 23% ± 6% of transuranium radionuclides originated from the Pacific Proving Grounds tests, and the rest (ca. 77%) from global fallout.

Using spectroscopic autoradiography of alpha particles for the quantitative mapping of 226Ra ultra-traces in geo-materials

The measurement of 226Ra and the identification of 226Ra-bearing minerals are important for studying the behavior of radium in the environment. Various instruments for measuring 226Ra are currently used: among the radiometric techniques that measure in bulk (no spatialization), there are gamma spectrometers and alpha spectrometers. Other instruments such as SEM-EDS can map the chemical elements thus providing information on the distribution of 226Ra, but are limited for ultra-trace analyses on natural geomaterials. Finally, autoradiography techniques can locate radioactivity, but are limited to the identification of the contribution of 226Ra when the 238U series is complete. This study focuses on spectroscopic autoradiography, a method for measuring both the energy of the alpha particle emissions and their positions on the autoradiograph. A gas detector based on a parallel ionization multiplier technology was used for this purpose. Alpha particle energy is dependent on the emitting radionuclides. In order to track the 226Ra, the energy spectrum of the 238U series was studied with modeling software. It appears possible to apply a thresholding on the energy spectrum to discriminate the 226Ra from the first alpha emitters of the 238U decay chain (i.e. 238U, 234U and 230Th, all below 5 MeV). The developed method was applied to a U-mill tailing sample prepared as a thin section. The sample was heterogeneous in terms of radioactivity and was not at secular equilibrium with 238U, as expected. The 226Ra was identified and localized, and different regions of interest were also analyzed with SEM-EDS elements cartography. This revealed 226Ra-rich barite (BaSO₄) phases measured at 3 ppmRa on average and containing no uranium; and uranium in siderite (FeCO3), showing a strong 226Ra deficit compared with secular equilibrium. Spectroscopic autoradiography opens up possibilities for the analysis of heterogeneous geological samples containing natural alpha emitters such as 238U and 226Ra: the 226Ra can be localized and quantified at ultra-trace content, and the method developed can also identify newly (young) uranium phases by measuring 238U/226Ra activity disequilibrium.

A fractional derivative model for nuclides transport in heterogeneous fractured media

Nuclide transport in fractured media involves the advection, dispersion, adsorption, etc. The dispersion and adsorption properties of the rock matrix have spatial variability, which results in an anomalous transport of nuclides. In this study, a time-fractional advection-diffusion equation (t-FADE) model is utilized to capture the sub-diffusion transport behavior with heavy-tail property, including the breakthrough curves (BTCs) of uranium and thorium transport in granite plates. Moreover, hydrodynamic dispersion of tritiated water, strontium and cesium in granite fractures are also studied. The results indicate that BTCs of nuclides transport in the granite fractures are unimodal and asymmetric. The decrease of the fractional order α reflects the stronger sub-diffusion. Furthermore, small initial velocity enhances sub-diffusion effect of nuclides and lengthens the breakout time of BTCs, which results in obvious heavy-tail phenomena. The analysis results demonstrate that the t-FADE model can accurately describe sub-diffusion behavior of nuclides transport. At last, the advantages of the t-FADE model in prediction and remediation of nuclides contamination are put forward.

The new QST bioassay laboratory in Chiba, Japan

Japan's National Institutes for Quantum Science and Technology (QST) was designated as the core radiation emergency medical support center by the country's Nuclear Regulation Authority (NRA) in 2019. One of the main missions of the QST is to maintain and improve its dose assessment capability for radiation-exposed individuals. Toward the goal of effectively fulfilling this mission, a new facility-the Dose Assessment Building for Advanced Radiation Emergency Medicine-was constructed at the Chiba base of the QST in 2020. An integrated bioassay laboratory was installed in this facility for assessing subjects' internal doses, along with a new integrated in vivo counter. The bioassay capability of the new laboratory is currently expected to screen 5-10 persons simultaneously assuming internal contamination with actinides such as Pu, Am/Cm and U, although this is dependent on the specific contamination circumstances.

Rapid and Simultaneous Determination of 238Pu, 239Pu, 240Pu, and 241Pu in Samples with High-Level Uranium Using ICP-MS/MS and Extraction Chromatography

As the most important plutonium isotopes, 238Pu, 239Pu, 240Pu, and 241Pu are normally measured by two to three techniques, which are tedious, time-consuming, and not suitable for rapid analysis in emergency situations. Recently, ICP-MS has become a competitive technique for the rapid measurement of 239Pu, 240Pu, and 241Pu. However, ICP-MS is difficult to measure 238Pu due to the serious isobaric interference of 238U. This work reports a rapid analytical method to solve this problem for the simultaneous determination of 238Pu, 239Pu, 240Pu, and 241Pu using triple-quadrupole inductively coupled plasma mass spectrometry (ICP-MS/MS) combined with chemical separation. Chemical separation achieved a high decontamination factor of 2.12 × 109 for the most critical interfering element, uranium, by using two sequential TK200 columns. The interferences of 238U1H+ and 238U+ were effectively eliminated by using 12 mL/min He-6 mL/min NH3 as the reaction gases in the octupole collision/reaction cell in ICP-MS/MS. Combined with chemical separation, the overall elimination efficiency of 238U1H+ reached 3.6 × 1017, which is 105 times better than the reported method. With the high 238U+ elimination efficiency of 1.12 × 104 in the ICP-MS/MS measurement, the overall removal efficiency of 238U+ reached 1013, guaranteeing accurate determination of femtogram-level 238Pu as well as 239Pu, 240Pu, and 241Pu in the samples containing milligram-level 238U. The detection time is reduced to minutes, well fulfilling the requirement of rapid analysis. This method is validated by analyzing the standard reference material and the spiked samples.

Simultaneous determination of femtogram levels of 237Np, 239Pu, and 240Pu in environmental solid samples using extraction chromatography and ICP-MS/MS

An analytical method based on triple quadrupole inductively coupled plasma mass spectrometry (ICP-MS/MS) was developed for simultaneous determination of femtogram levels of ²³⁷Np, ²³⁹Pu, and ²⁴⁰Pu in environmental samples. By carefully controlling the valence states of Np and Pu in the entire separation procedure using a simple single extraction chromatographic column (TK200), the consistent behavior of Np and Pu was achieved, allowing for the reliable application of ²⁴²Pu as the chemical yield tracer for ²³⁷Np, ²³⁹Pu, and ²⁴⁰Pu. A high decontamination factor of 3.2 × 10⁷ for the most critical interfering element, uranium, was achieved in the chemical separation step. The interferences of ²³⁸U¹H⁺ and peak tailing of ²³⁸U⁺ during the measurement of plutonium isotopes were effectively eliminated by utilizing 7.5 mL/min He-1.1 mL/min CO₂ as reaction gases in the octupole collision/reaction cell and employing sequential quadrupole mode for mass separation in ICP-MS/MS. Specifically, the interference of ²³⁸U¹H⁺ was reduced to 10^-6 and the peak tailing of ²³⁸U⁺ to 10^-10, surpassing the performance of measurement method without reaction gases by 3 orders of magnitude. The developed method enables the accurate determination of femtogram levels of ²³⁷Np, ²³⁹Pu, and ²⁴⁰Pu in the samples with U/Np and U/Pu atom ratios of up to 10¹⁷ and 10¹², respectively. The developed method was validated by analyzing standard reference materials and spiked soil samples.

Innovative ICP-MS/MS Method To Determine the 135Cs/137Cs Ratio in Low Activity Environmental Samples

The ¹³⁵Cs/¹³⁷Cs isotopic ratio is a powerful tool for tracing the origin of radioactive contamination. Since the Fukushima accident, this ratio has been measured by mass spectrometry in several highly contaminated environmental matrices mainly collected near nuclear accident exclusion zones and former nuclear test areas. However, few data were reported at ¹³⁷Cs environmental levels (<1 kBq kg^-1). This is explained by the occurrence of analytical challenges related to the very low radiocesium content at the environmental level with the large presence of mass interferences, making ¹³⁵Cs and ¹³⁷Cs measurements difficult. To overcome these difficulties, a highly selective procedure for Cs extraction/separation combined with an efficient mass spectrometry measurement must be applied on a quantity of ca. 100 g of soil. In the current research, an innovative inductively coupled plasma-tandem mass spectrometry (ICP-MS/MS) method has been developed for the ¹³⁵Cs/¹³⁷Cs ratio measurement in low activity environmental samples. The use of ICP-MS/MS led to a powerful suppression of ¹³⁵Cs and ¹³⁷Cs interferences by introducing N₂O, He, and, for the first time, NH₃, into the collision-reaction cell. By adjusting the flow rates of these gases, the best compromise between a maximum signal in Cs and an effective interference elimination was achieved allowing a high Cs sensitivity of more than 1.10⁵ cps/(ng g^-1) and low background levels at m/z 135 and 137 lower than 0.6 cps. The accuracy of the developed method was successfully verified by analyzing two certified reference materials (IAEA-330 and IAEA-375) commonly used in the literature as validation samples and three sediment samples collected in the Niida River catchment (Japan) impacted by the Fukushima fallout.

Impact of the Fukushima Accident on 3H and 14C Environmental Levels: A Review of Ten Years of Investigation

The investigation of the impact of the Fukushima accident is still going on although more than ten years have passed since the disaster. The main goal of this paper was to summarize the results of tritium and radiocarbon determinations in different environmental samples, possibly connected with the Fukushima Dai-ichi Nuclear Power Plant (FDNPP) accident. A document containing compiled data may serve as a solid basis for further research in the selected fields. To accomplish such effort, we went through dozens of relevant published papers, reporting 3H and 14C activity concentrations in precipitations, groundwater, seawater, river systems, tree rings, and, in some more extraordinary samples, such as herbaceous plants or debris from the damaged reactor buildings. As the referenced results would not be obtainable without adequate analytical techniques, the most common methods for routine measurement of tritium and radiocarbon concentrations are discussed as well. We believe that the correct identification of the affected environmental compartments could help quantify the released 3H and 14C activities and track their following fate, which could be especially important for plans to discharge contaminated water from the FDNPP in the upcoming years.

A new methodology based on TRU resin to measure U-, Th-isotopes and 210Po by alpha-particle spectrometry

This report presents a new methodology to isolate and measure ²¹⁰Po, as well as uranium and thorium isotopes. This new methodology reduces the standard time of operation, the minimum amount of chemical reagents and the quantity of resin used in comparison with other standard and well-established procedures for alpha spectrometry. Thus, the amount of chemicals reagent was lower than the amount used in other standard radiochemical processes: only 6 mL of 1 M HCl was used for the thorium elution, and 2 mL of H₂O and 1 mL of Ammonium Oxalate (0.05 M) (3 mL in total) for the uranium elution. Likewise, many samples of various activities and materials (liquids and solids) were used to validate the method.

Evaluation of Graphene Oxide as a Thermal Ionization Enhancer for Plutonium in TIMS Measurement

Thermal ionization mass spectrometry (TIMS) has been extensively employed for the assessment of plutonium (Pu) isotopes in nuclear forensics and environmental monitoring. Recently, great efforts have been made to improve the ionization efficiency (IE) of Pu to achieve better accuracy and precision for trace-level analysis. Herein, the thermal ionization enhancement effect for plutonium of graphene oxide (GO) was investigated and the corresponding mechanism was discussed. The GO layers were homogeneously mounted on the filament's central surface to promote pg-level Pu ion emission. With the excellent structural property of GO, a greatly promoted ionization efficiency of 0.44% for Pu was obtained, and the initial ionization temperature for Pu was remarkably reduced from 1610 to 1390 °C. Average boosts in IE compared to the classical double-filament mode and graphite-loaded single-filament mode were 1640 and 520%, respectively. The analytical accuracy and precision based on the GO-loaded single-filament mode were validated using Pu isotopic certified reference materials. This work demonstrates the excellent property of GO as an ion source additive for Pu ionization, as it provided an interface for the promotion of energy transfer and Pu carbide formation. The operation of GO loading is quite simple and can be finished within 5 min. This rapid filament carburization approach has great potential for improving the measurement precision of trace-level plutonium isotopes and can be applied in nuclear safeguards, nuclear forensics, and environmental monitoring.

Intercomparison exercise on difficult to measure radionuclides in spent ion exchange resin

A need for method validation in radiochemical analyses of decommissioning waste is a challenging task due to lack of commercial reference materials. Participation in an intercomparison exercise is one way for a laboratory to assess their performance and validate their analysis results. A three-year project within the Nordic Nuclear Safety Research (NKS) community was initiated in order to carry out intercomparison exercises on difficult to measure (DTM) radionuclides in real decommissioning waste. Both Nordic and Non-Nordic laboratories participated. This paper reports the results from the final year of the project focusing on beta- and gamma emitter (i.e., easy to measure, ETM) analysis in spent ion exchange resin. The assigned values were derived from the participants’ results according to ISO 13528 standard and the performances were assessed using z scores. The results showed generally good performances for both DTMs and ETMs.

Investigation of self-attenuation of 210Pb (46 keV) gamma ray in sediment, certified reference material and high-density minerals: Implication to precise measurement of 210Pb

High resolution gamma spectrometry is one of the most widely used techniques in the measurements of environmental level 210Pb in sediment from coastal and freshwater environments and such measurements are needed to establish 210Pb chronology for the past 100-150 years. Precise measurement of 210Pb in sediment and soil requires appropriate self-absorption correction for its low-energy (46.5 keV) gamma radiation due to differences in the matrix between the sample and standard used to calibrate the instrument. Here we report a method that involves precise determination of 210Pb activity in sediment sample by calibrating the HPGe well detector with RGU-1-IAEA Certified Reference Material for well-defined geometries. A comparison of the 210Pb activity obtained from gamma-ray spectrometry with that obtained from alpha spectrometry via 210Po, using 209Po as yield tracer, indicates good agreement. We propose an empirical relation between the absolute efficiencies and packing densities of sample in a well-defined geometry (cylindrical counting vial) by affecting the count rate of 210Pb and its progenitor, 226Ra (via 214Pb and 214Bi). The effects of self-attenuation of 46.5 keV (210Pb), for naturally-occurring high-density minerals (apatite, titanite, monazite, and cerite) are evaluated. Specific activity of 210Pb on apatite measured by alpha and gamma spectrometry are compared. This study is relevant and useful for precise measurements of gamma-emitting environmental radionuclides such as 210Pb, 7Be, 137Cs as well as 226Ra.

Determination of 241Am in Environmental Samples: A Review

The determination of 241Am in the environment is of importance in monitoring its release and assessing its environmental impact and radiological risk. This paper aims to give an overview about the recent developments and the state-of-art analytical methods for 241Am determination in environmental samples. Thorough discussions are given in this paper covering a wide range of aspects, including sample pre-treatment and pre-concentration methods, chemical separation techniques, source preparation, radiometric and mass spectrometric measurement techniques, speciation analyses, and tracer applications. The paper focuses on some hyphenated separation methods based on different chromatographic resins, which have been developed to achieve high analytical efficiency and sample throughput for the determination of 241Am. The performances of different radiometric and mass spectrometric measurement techniques for 241Am are evaluated and compared. Tracer applications of 241Am in the environment, including speciation analyses of 241Am, and applications in nuclear forensics are also discussed.

Rapid radionuclide specific screening procedures in drinking water: alternative options to replace inaccurate gross activity measurements

It was concluded from two European wide proficiency tests that the gross alpha/beta methods used for drinking water analysis have fundamental pitfalls regardless of the specific gross-counting methods. The majority of gross-counting methods suffer from serious trueness and repeatability issues. To replace inaccurate gross activity measurements an alternative rapid radionuclide specific screening procedure for water analysis is proposed. This procedure considers liquid scintillation counting, alpha-particle- and gamma-ray spectrometry. The proposed procedure is more robust and can achieve lower uncertainties than gross-counting methods. Furthermore, qualitative and quantitative analytical data can be obtained with turnaround times comparable to the gross-counting methods.

An efficient method for the removal of Pb prior to the ultra-trace Am measurement by ICP-MS

The existence of Pb which formed polyatomic ions such as PbCl+, PbAr+ would interfere the determination of ultra-trace Am by ICP-MS. An extraction chromatography method for the removal of Pb interference was provided in this work to improve the determination accuracy of ultra-trace Am by ICP-MS. In this study, Sr resin was applied to separate Am and Pb because of the great difference between Am and Pb on adsorption ability. The variable parameters including nitric acid concentration, loading volume, column height and loading amount were investigated to optimize the separation conditions for high recovery of Am (R(Am)) as well as high decontamination factor of Pb (DF(Pb)). The optimal separation method was recommended in the study with the recovery of Am over 99% and the decontamination factor of Pb over 2 × 105. Moreover, the method was successfully applied to the analysis of 241Am in the simulated samples.

226Ra and 137Cs determination by inductively coupled plasma mass spectrometry: state of the art and perspectives including sample pretreatment and separation steps

Achieving precise and accurate quantification of radium (²²⁶Ra) and cesium (¹³⁷Cs) by inductively coupled plasma mass spectrometry (ICP-MS) is of particular interest in the field of radiological monitoring and more widely in environmental and biological sciences. However, the accuracy and sensitivity of the quantification depend on the analytical strategy implemented. Eliminating interferences during the sample handling step and/or during the analysis step is critical since presence of matrix elements can lead to spectral and non-spectral interferences in ICP-MS. Consequently, before the ICP-MS analysis, multiple sample preparation approaches have been applied to purify and/or pre-concentrate environmental and biological samples containing radium and cesium through years, such as (co)-precipitation, solid phase extraction (SPE) or dispersive SPE (dSPE). Separation steps using liquid chromatography and capillary electrophoresis can also be useful in complement with the abovementioned sample preparation techniques. The most attractive sample handling technique remains SPE but efficiency of the extraction procedures is currently limited by sorbent specificity. Indeed, with the recent advances in ICP-MS instrumentation, it becomes indispensable to eliminate residual interferences and improve sensitivity. It is in this direction that it will be possible to meet analytical challenges, e.g. analyzing radium and cesium at concentrations below the pg L^-1 range in complex matrices of small volumes, as they are found for instance in pore waters or in biological samples. Development of new innovative sorbents based for example on hybrid and nanostructured materials has been reported with the aim of enhancing sorbent specificity and/or capacity. In the present review, the performances of the different analytical approaches are discussed, followed by an overview of applications.

A review on the use of lichens as a biomonitoring tool for environmental radioactivity

Lichens have been widely used as a biomonitoring tool to record the distribution and concentration of airborne radioactivity and pollutants such as metals. There are limitations, however: although pollutants can be preserved in lichen tissues for long periods of time, not all radioactive and inert elements behave similarly. The chemical species of elements at the source, once captured, and the mode of storage within lichens play a role in this biomonitoring tool. Lichens are a symbiotic association of an algal or cyanobacterial partner (photobiont) with a fungal host (mycobiont). Lichens grow independently of the host substrates, including rocks, soils, trees and human-made structures. Lacking a root system, lichen nutrient or contaminant uptake is mostly through direct atmospheric inputs, mainly as wet and dry deposition. As lichens grow in a large variety of environments and are resilient in harsh climates, they are adapted to capture and retain nutrients from airborne sources. The context of this review partially relates to future deployment of small modular reactors (SMRs) and mining in remote areas of Canada. SMRs have been identified as a future source of energy (electricity and heat) for remote off-grid mines, potentially replacing diesel fuel generation facilities. For licensing purposes, SMR deployment and mine development requires capabilities to monitor background contaminants (natural radioactivity and metals) before, during and after deployment, including for decommissioning and removal. Key aspects reviewed herein include: (1) how lichens have been used in the past to monitor radioactivity; (2) radiocontaminants capture and storage in lichens; (3) longevity of radiocontaminant storage in lichen tissues; and (4) limitations of lichens use for monitoring radiocontaminants and selected metals.

Uncertainty and detection limits of 241Pu determination by liquid scintillation counting (LSC)

Determination of ²⁴¹Pu is an essential issue for radiation protection, as it is the precursor of some nuclides with high radiotoxicity. ²⁴¹Pu is a low energy beta emitter, which makes its measurement more challenging than that of Pu alpha emitters. The most widely used method for the measurement of ²⁴¹Pu is liquid scintillation counting (LSC). In this method, the assessment of Pu radiochemical yield is done by measuring the sample by alpha spectrometry before being lixiviated and measured by LSC. This double measurement affects uncertainty analysis, as well as decision threshold and detection limit, considering that both components of the total yield (radiochemical and lixiviation) should be contemplated. In this paper, and for quality assurance (QA) purposes, in-depth uncertainty and detection limit formulae for the proposed method, controlling correlations and considering all the parameters involved including chemical and lixiviation yields, have been developed. A sensitivity analysis of the uncertainty budget together with an assessment of ²⁴²Pu tracer quantity to be used, ensuring a total yield of at least 50% and a relative uncertainty of the leaching yield of at most 5%, have been carried out. In addition, an analysis of the impact of the real lixiviation yield value and its uncertainty on the results has been done. As a general conclusion, and considering the values of the parameters chosen for this work (samples of 1 g measured for 24 h by LSC), the ²⁴¹Pu uncertainties range from 5% to 30% depending on the activity concentration values and the detection limits range from 14 to 30 Bq kg^-1, depending on yield values. The main components of the uncertainty budget are the net ²⁴¹Pu and background counts obtained in the LSC measurement for low contaminated samples while this is the case for the alpha gross count rate in LSC measurement of the alpha calibration source for highly contaminated samples. In addition, an analysis of possible interference by Pu alpha emitters in the ²⁴¹Pu signal and a comparison of quench standard curves of ³H and ²⁴¹Pu are also performed.

Radiochemical Determination of Long-Lived Radionuclides in Proton-Irradiated Heavy Metal Targets: Part II Tungsten

In this study, proton-irradiated tungsten targets, up to 2.6 GeV, were investigated for the purpose of the experimental cross-section measurements. Radiochemical separation methods were applied to isolate the residual long-lived alpha-emitters ¹⁴⁸Gd, ¹⁵⁴Dy, and ¹⁴⁶Sm and the beta-emitters ¹²⁹I and ³⁶Cl from proton-irradiated tungsten targets. The molecular plating technique has been applied to prepare ¹⁴⁸Gd, ¹⁵⁴Dy, and ¹⁴⁶Sm samples for alpha-spectrometry. Production cross-sections of ¹²⁹I and ³⁶Cl were determined by means of accelerator mass spectrometry. The results are compared with theoretical predictions, obtained with the INCL++-ABLA07 codes, showing good agreement for ³⁶Cl and ¹⁴⁸Gd, while a factor of 4 difference was observed for ¹⁵⁴Dy, similar to the results obtained for tantalum targets.

Analyzing alpha emitting isotopes of Pu, Am and Cm from NPP water samples: an intercomparison of Nordic radiochemical laboratories

Radioanalytical methods for the determination of isotopes of Pu, Am and Cm in water samples from nuclear power plants were compared and further developed in a Nordic project (Optimethod) through two intercomparison exercises among Nordic laboratories. With this intercomparison, the analytical performance of some laboratories was improved by modification of the analytical method and adopting new techniques. The obtained results from the two intercomparisons for alpha emitting transuranium isotopes are presented, and the lessons learnt from these intercomparison exercises are discussed.

Online Solid-Phase Extraction-Inductively Coupled Plasma-Quadrupole Mass Spectrometry with Oxygen Dynamic Reaction for Quantification of Technetium-99

Quantification of pg/L levels (i.e., 0.6 mBq/L) of radioactive technetium-99 (⁹⁹Tc) was achieved within 15 min in the presence of isobaric and polyatomic interference sources such as ruthenium-99 (⁹⁹Ru) and molybdenum hydride (⁹⁸Mo¹H) at 3-11 orders of magnitude higher concentrations. Online solid-phase extraction-inductively coupled plasma-quadrupole mass spectrometry (ICP-QMS) with oxygen (O₂) dynamic reaction cell (online SPE-ICP-MS-DRC) was shown to be a thorough automatic analytical system, circumventing the need for human handling. At three stepwise separations (SPE-DRC-Q mass filters), we showed that interference materials allowed the coexistence of abundance ratios of 1.5 × 10^-13 and 1.1 × 10^-5 for ⁹⁹Tc/Mo and ⁹⁹Tc/Ru, respectively. A classical mathematical correction using the natural isotope ratio of ⁹⁹Ru/¹⁰²Ru was used to calculate the residues of ⁹⁹Ru. Using this optimized system, a detection limit (DL; 3σ) of ⁹⁹Tc was 9.3 pg/L (= 5.9 mBq/L) for a 50 mL injection and sequential measurements were undertaken at a cycle of 24 min/sample. For the measurement of a lower concentration of ⁹⁹Tc, an AG1-X8 anion-exchange column was used to study 20 L of seawater. Its DL was approximately 1000 times greater than that of previous methods (70.0 fg/L). Thus, this method withstands coexistences of 5.8 × 10^-18 and 3.5 × 10^-9 for ⁹⁹Tc/Mo and ⁹⁹Tc/Ru, respectively. Spike and recovery tests were conducted for environmental samples; the resulting values showed good agreement with the spike applied.

Determination of ultra-trace level plutonium isotopes in soil samples by triple-quadrupole inductively coupled plasma-mass spectrometry with mass-shift mode combined with UTEVA chromatographic separation

Although triple-quadrupole inductively coupled plasma-mass spectrometry (ICP-MS/MS) has become an attractive technique for the measurement of long-lived radionuclides, the abundance sensitivity, isobaric and polyatomic ions interferences seriously restrict the application. The spectral peak tailing and uranium hydrides (UH⁺, UH₂⁺) from ²³⁸U have a serious influence on the accurate measurement of ²³⁹Pu and ²⁴⁰Pu, especially for the ultra-trace level plutonium isotopes in the higher uranium sample. A new method was developed using ICP-MS/MS measurement in mass-shift mode with collision-reaction gas combined with a chemical separation procedure. As O₂ readily converted Pu⁺ ion to PuO₂⁺, while disassociated the interfering diatomic ions of interfering elements (U, Pb, Hg, Tl, etc.), the interferences from these elements were completely eliminated if plutonium was detected as PuO₂⁺ at the m/z more than 270. By the mass filter in MS/MS mode combined with O₂ as reaction gas the lower peak tailing of ²³⁸U⁺ (<5 × 10^-12) was significantly suppressed. By this way, the ²³⁸UO₂H⁺/²³⁸UO₂⁺ atomic ratio was reduced to 4.82 × 10^-9, which is significantly lower than that of other collision-reaction gas modes. Interferences from Pb, Hg and Tl polyatomic ions were also completely eliminated. Thus, accurate measurement of ultra-trace level ²³⁹Pu in high uranium sample solutions with the ²³⁹Pu/²³⁸U concentration ratio of 10^-10 was achieved by the mass-shift mode with 0.15 mL/min O₂/He + 12.0 mL/min He as collision-reaction gas, and high elimination efficiency of uranium interferences up to 10¹⁴ can be obtained by combination with the chemical separation using a single UTEVA resin column. The developed method can be applied to accurately determine the fg level ²³⁹Pu in high uranium samples, such as large-size deep seawater, deep soil and sediment, uranium debris of nuclear fuel.

Rapid analysis of 237Np and Pu isotopes in small volume urine by SF-ICP-MS and ICP-MS/MS

Internal contamination with alpha-particle emitting actinides, such as ²³⁷Np, ²³⁹Pu, ²⁴⁰Pu, is likely to bring a large amount of dose to the tissues of persons even if the intake amount is small. To provide timely information for prompt decision-making in radiation emergency therapy, we developed a simple and rapid method for urinary bioassay to determine ultra-trace ²³⁷Np and Pu isotopes using SF-ICP-MS and ICP-MS/MS. To avoid polyatomic interferences and tailing effects from U, ²³⁷Np and Pu isotopes were collected after removing U effectively using a simple single chromatographic column packed with 2 mL AG MP-1M anion exchange resin, exhibiting a high decontamination factor of 10⁸ for ²³⁸U. The overall chemical fractionation between ²³⁷Np and ²⁴²Pu for the whole analytical procedure was 0.974 ± 0.064 (k = 2), allowing us to measure ²³⁷Np and Pu isotopes using ²⁴²Pu as a yield tracer with yields of 76 ± 5%. Using ICP-MS/MS with low background provided the method detection limits for ²³⁷Np, ²³⁹Pu, ²⁴⁰Pu, and ²⁴¹Pu of 0.025, 0.025, 0.015, and 0.020 fg mL^-1, respectively, for 20 mL of urine sample. Those were comparable to detection limits of SF-ICP-MS with high sensitivity. Subsequently, three urine reference materials with Pu spike, provided by the Association for the PROmotion of Quality COntrol in RADiotoxicological Analysis (PROCORAD), France, were analyzed by the developed method and the conventional alpha spectrometry technique for validation. Finally, the developed method was successfully employed to measure the contamination level of ²³⁷Np, ²³⁹Pu, ²⁴⁰Pu, and ²⁴¹Pu in urine samples collected during decorporation therapy using DTPA, after a Pu inhalation exposure accident in Japan. The high throughput (9 h for 12 samples), simplicity, low cost, and high sensitivity of the method will allow greater numbers of related laboratories to be involved in screening activities for unexpected actinide exposure, such as in the case of a large scale radiological disaster.

A rapid, automated system for the separation, preconcentration and measurement of 90Sr, and U, Am and Pu isotopes

An online separation and preconcentration method, using an automated flow injection setup and solid phase extraction followed by ICP-MS/MS, was developed for the analysis of ⁹⁰Sr, and U, Am and Pu isotopes in various liquid sample matrices. The radionuclide analytes were separated from interferences and complex matrices using DGA-branched resin and Sr resin, then specific gases were used in the reaction/collision cell in the ICP-MS/MS to measure the different analytes. The system requires smaller sample volumes (10 mL), less sample preparation and shorter processing time (46 min per sample) compared to traditional radiometric and other MS techniques. Based on a 10 mL sample, the limits of detection were 1.48 pg L^-1 (8257 mBq L^-1) for ⁹⁰Sr, 1.75 pg L^-1 (0.40 mBq L^-1) for ²³⁴U, 0.65 pg L^-1 (77.65 mBq L^-1) for ²⁴¹Am, and 0.56 pg L^-1 (1.25 mBq L^-1) for ²³⁹Pu when all target analytes were measured in one analysis. The analytical figures of merit were evaluated for a range of sample matrices including lake water, seawater and urine and were comparable to those reported in the literature. This online system thus provides a novel, fully automated analytical tool with faster analysis time, smaller sample requirements, minimum sample preparation, low detection limits and the flexibility to handle single and multiple measurements of various radionuclides.

Atmospheric fallout of radionuclides in peat bogs in the Western Segment of the Russian Arctic

This article presents the results of studies of the activity of radionuclides in peat-bog profiles of the European subarctic of Russia. Two peat profiles were collected in different areas of the Arkhangelsk region. The peat cores were used to determine ²¹⁰Pb, ¹³⁷Cs, ²⁴¹Am, ²³⁹Pu, ²⁴⁰Pu, ²³⁸U, and ²³⁴U content. To estimate the relationship between radionuclide activity and physicochemical parameters of peat, the content of organic matter, water-soluble salts, carbonates and ash, and the pH of aqueous and salt extracts were studied. Radionuclide activity concentrations in peat samples were measured using inductively coupled plasma mass spectrometry (ICP-MS), low-background semiconductor gamma spectrometry with a high-purity germanium (HPGe) detector, and alpha spectrometry. The ²¹⁰Pb chronology of peat cores was studied using a constant flow model based on the Monte Carlo simulation method. Comparison of ²¹⁰Pb dating data showed that the position of the maximum activity peaks of anthropogenic radionuclides shifted along the peat profile. This is probably due to the relative mobility of different radionuclides in the peat massif. Measurement of the atomic ratio ²⁴⁰Pu/²³⁹Pu showed that the main sources of pollution in the peatlands of the European subarctic of Russia are global fallout from atmospheric tests from the 1950s through 1980 and fallout from the Chernobyl nuclear accident in 1986. This study shows that a complex of radioactive isotopes in peat deposits can provide valuable information on the environmental pollution loads of subarctic territories.

Unveiling the Uncommon Fluorescent Recognition Mechanism towards Pertechnetate Using a Cationic Metal-Organic Framework Bearing N-Heterocyclic AIE Molecules

As one of most problematic radionuclides, technetium-99, mainly in the form of anionic pertechnetate (TcO₄ ^- ), exhibits high environmental mobility, long half-life, and radioactive hazard. Due to low charge density and high hydrophobicity for this tetrahedral anion, it is extremely difficult to recognize it in water. Seeking efficient and selective recognition method for TcO₄ ^- is still a big challenge. Herein, a new water-stable cationic metal-organic framework (ZJU-X8) was reported, bearing tetraphenylethylene pyrimidine-based aggregation-induced emission (AIE) ligands and attainable silver sites for TcO₄ ^- detection. ZJU-X8 underwent an obvious spectroscopic change from brilliant blue to flavovirens and exhibited splendid selectivity towards TcO₄ ^- . This uncommon fluorescent recognition mechanism was well elucidated by batch sorption experiments and DFT calculations. It was found that only TcO₄ ^- could enter into the body of ZJU-X8 through anion exchange whereas other competing anions were excluded outside. Subsequently, after interaction between TcO₄ ^- and silver ions, the electron polarizations from pyrimidine rings to Ag⁺ cations significantly lowered the energy level of the π* orbital and thus reduced the π-π* energy gap, resulting in a red-shift in the fluorescent spectra.

Online Biogenic Carbon Analysis Enables Refineries to Reduce Carbon Footprint during Coprocessing Biomass- and Petroleum-Derived Liquids

To mitigate green-house gas (GHG) emissions, governments around the world are enacting legislation to reduce carbon intensity in transportation fuels. Coprocessing biomass and petroleum-derived liquids in existing refineries is a near-term, cost-effective approach for introducing renewable carbon in fuels and enabling refineries to meet regulatory mandates. However, coprocessing biomass-derived liquids in refineries results in variable degrees of biogenic carbon incorporation, necessitating accurate quantification to verify compliance with mandates. Existing refinery control and instrumentation systems lack the means to measure renewable carbon accurately, reliably, and quickly. Thus, accurate measurement of biogenic carbon is key to ensuring refineries meet regulatory mandates. In this Perspective, we present existing methods for measuring biogenic carbon, point out their challenges, and discuss the need for new online analytical capabilities to measure biogenic carbon in fuel intermediates.

Determination of Pu-239 in Urine by Sector Field Inductively Coupled Plasma Mass Spectrometry (SF-ICP-MS) Using an Automated Offline Sample Preparation Technique

Here we report a new procedure to determine Pu-239 in urine using a custom-made automated pre-analytical processing system (single probe) with Pu-242 as a tracer followed by analysis by SF-ICP-MS. An average Pu-242 recovery rate of 88% was obtained with CF-ThU-1000 columns reused >100 times. Analytical results agree with measurements obtained using the CDC manual method with a R2 of 0.9994. Results for Oak Ridge National Laboratory (ORNL) reference materials (RM) align with target values with a bias range of -3.44% to 3.05%. The limit of detection for this method is 0.63 pg/L, which is comparable to previous manual methods.