Embedding products and methods for the transport, storage and / or handling of lanthanides or actinides - Patents.com

Abstract

The present invention relates to an embedment product suitable for transporting, storing and / or handling lanthanides, actinides or compounds thereof. The present invention further relates to a method for producing the embedment product and to a method for determining the concentration of at least one analyte in a sample.

Description

[Technical field]

[0001] The present invention relates to an embedment product suitable for transporting, storing and / or handling lanthanides, actinides or compounds thereof. The present invention further relates to a method for producing said embedment product and to a method for determining an analyte in a sample, the sample being spiked with the embedment product. [Background technology]

[0002] Radionuclides and heavy metals or their compounds, such as lanthanides, actinides or their compounds, are essential components of industry and are widely used in domestic and technical applications. Nevertheless, their known toxicity poses a risk of environmental contamination, raising ecological and global public health concerns. The release of such elements and their use are therefore strongly regulated. For this purpose, field samples are routinely collected and the presence of such elements is controlled, in particular by quantitative analysis. Such controls are typically carried out off-site and may be carried out by safety agencies for regulatory purposes.

[0003] Therefore, preservation of the field samples during transport and storage is paramount to ensure reliable control. Furthermore, measures must be taken for the handling of such elements.

[0004] This is especially true when quantitative analyses are performed. Indeed, quantitative analyses require rigorous procedures to determine with high precision the unknown composition of a sample, especially when the elements to be analyzed are in trace amounts, as is generally the case for radionuclides and heavy metals. For this purpose, measurement laboratories need to implement essential quality control measures and validated methods. Such quality control measures require the use of reference materials or certified reference materials, either as instrument calibration means or as spikes. Such reference materials or certified reference materials provide a standard for measurement laboratories to deliver accurate and comparable results. Reference materials are referred to as materials that are sufficiently homogeneous and stable with respect to one or more specific properties. According to the International vocabulary of metrology-Basic and general concepts and associated terms(VIM)JCGM 200:2012, certified reference materials are reference materials in the sense that one or more of those properties are characterized by metrologically valid procedures. They are accompanied by a certificate stating the values ​​of the specific properties with their associated uncertainties and a statement of metrological traceability. Reference and certified reference materials have established properties that make them suitable for their intended use in measurements. Certified reference measurements are metrological tools for accurate measurements.

[0005] Typically, reference materials are manufactured in a dedicated location that is different from the location where they are analyzed, and therefore, these reference materials also need to be preserved during transportation, storage and handling in order to perform an accurate quantitative analysis.

[0006] Means for transporting, storing and handling reference materials are known in the art.

[0007] For example, it is known to use media for the storage of metal particles, as notably described by R. Middendorp et al. (ESARDA Bulletin n° 54, June 2017, p. 25-30). This paper discloses that uranium fine particles are suspended in ethanol, with the aim of simplifying the handling and storage of said particles. A drawback of such ethanol suspensions is their stability over longer periods, since they are only stable over a period of several months. Long-term stability is important in view of the growing market demand and the shortage of high-purity metals.

[0008] It is also known in the art to embed uranium and / or plutonium in polysaccharides with a high degree of polymerization, i.e. large polysaccharide-based matrices, as described in particular by R. Jakopic et al., who used polysaccharides with a number average molecular weight M of 70,000 to embed uranyl nitrate and plutonium nitrate with the aim of providing large dry spikes capable of preserving said uranium and / or plutonium during storage and transport. n It has been described that the use of polysaccharide-based matrices such as cellulose acetate butyrate (CAB) (preparation and certification of Large-Sized Dried (LSD) spike IRMM-1027o, EUR 25857EN, 2013) or, alternatively, cellulose acetate butyrate / dioctyl phthalate (CAB / DOP) or carboxymethylcellulose (CMC) (preparation and certification of Large-Sized Dried (LSD) spike IRMM-1027t, EUR 29742EN, 2019) is effective in reducing the amount of cellulose acetate butyrate in the preparation of the spike. However, the manufacturing process of said Large-Sized Dried spike is tedious and long, especially involving a time-consuming heating / drying step. Moreover, the manufacturing process of such Large-Sized Dried spikes has been found to be very sensitive to laboratory conditions such as humidity, heating / drying temperature and time, which inevitably affects its reproducibility. Thus, the production capacity of such LSD spikes is limited.

[0009] There is therefore a need to provide embedded products of lanthanides, actinides, or compounds thereof that are suitable for transport, storage and / or handling of said lanthanides, actinides, or compounds thereof, said embedded products having long-term stability, while the manufacturing process thereof is time-efficient and highly reproducible. Summary of the Invention

[0010] The inventors have surprisingly found that it is possible to provide an improved embedded product which meets the above-mentioned needs and overcomes the above-mentioned disadvantages.

[0011] It is therefore an object of the present invention to provide an embedded product suitable for transport, storage and / or handling of lanthanides, actinides or compounds thereof, the embedded product comprising, relative to the total weight of the embedded product: - at least 60.0% by weight (wt.%) of a matrix material (MA), said matrix material (MA) comprising more than 55.0 wt.% of at least one saccharide selected from the group consisting of monosaccharides, disaccharides, trisaccharides and tetrasaccharides (hereinafter saccharides (S)) relative to the total weight of the matrix material (MA); at least one lanthanide, actinide or compound thereof, in which the molar ratio of sugars (S) to the at least one lanthanide, actinide or compound thereof in the embedded product is greater than 1.5; and (b) providing an encapsulation product suitable for transporting, storing and / or handling lanthanides, actinides or compounds thereof, comprising:

[0012] In another aspect, the present invention provides a method for producing an embedded product, as detailed above.

[0013] In another aspect, the present invention provides a method for determining the concentration of at least one analyte in a sample (SA), said sample (SA) being spiked with an embedding product as detailed above.

[0014] In another aspect, the present invention provides the use of an embedding product as detailed above in a method for determining the concentration of an analyte in a sample (SA) as detailed above. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] Detailed Description of the Invention Within the context of the present invention, the term "comprising" should not be interpreted as being limited to the means recited thereafter, and does not exclude other elements or steps. It should be interpreted as specifying the presence of the mentioned recited features, integers, steps or ingredients, but does not exclude the presence or addition of one or more other features, integers, steps or ingredients, or groups thereof. Thus, the scope of the expression "a composition comprising components A and B" should not be limited to a composition consisting of components A and B only. It means that in the context of the present invention, the only relevant components of the composition are A and B. Thus, the terms "comprising" and "including" encompass the more restrictive terms "consisting essentially of" and "consisting of".

[0016] The inventors have surprisingly found that by providing an embedding material comprising a matrix material (MA), said matrix material (MA) comprising more than 55% by weight of at least one saccharide selected from the group consisting of monosaccharides, disaccharides, trisaccharides and tetrasaccharides (hereinafter saccharides (S)) relative to the total weight of the matrix material (MA), the embedding material exhibits excellent stability. In other words, the embedded material obtained thereby does not show signs of peeling or cracking over time. As a result, the embedded material can be transported and handled in a safe manner by efficiently embedding at least one lanthanide, actinide or compound thereof, thereby avoiding their leaching. Furthermore, the embedded material can be stored for a longer time, thereby providing a reliable source of at least one lanthanide, actinide or compound thereof.

[0017] Furthermore, the inventors have surprisingly found that the embedding products of the invention exhibit excellent homogeneity, so that when the embedded material is used in a quantitative analysis, for example as the sample to be analyzed, as a calibration average, or as a spike, undesired bias and uncertainty in the quantitative analysis measurements can be effectively reduced.

[0018] Within the context of the present invention, the terms "homogeneity" or "homogeneous" are intended to refer to at least one lanthanide, actinide, or compound thereof being uniformly distributed in the matrix material (MA), in other words, a homogeneous embedding product does not exhibit aggregates of the at least one lanthanide, actinide, or compound thereof.

[0019] Without being bound by this theory, it is believed that the sugars (S) according to the invention act as an embedding agent, allowing the lanthanides or actinides or their compounds to strongly interact with said sugars (S). As a result, the embedding of lanthanides, actinides or their compounds is highly favorable. This strong interaction is surprising, since the skilled person would not have been prompted to use small molecules such as the sugars (S) according to the invention to enhance the embedding properties. In contrast, the skilled person would have chosen highly polymerized compounds that provide entropically favorable embedding properties due to their covalently bonded units. As will be explained in detail in the following examples, it is clear that the sugars (S) have a clear positive impact on the stability and homogeneity of the embedded product.

[0020] As mentioned above, the matrix material (MA) of the embedded product according to the invention comprises more than 55% by weight of at least one saccharide selected from the group consisting of mono-, di-, tri- and tetrasaccharides (hereinafter saccharides (S)) relative to the total weight of the matrix material (MA).

[0021] Within the context of the present invention, the expression "at least one saccharide selected from the group consisting of monosaccharides, disaccharides, trisaccharides and tetrasaccharides (hereinafter saccharide (S))" is intended to denote one saccharide (S) or two or more saccharides (S). Mixtures of saccharides (S) may also be used.

[0022] In the remainder of the text, the expression "saccharide (S)" is to be understood for the purposes of the present invention both in the plural and in the singular.

[0023] Within the context of the present invention, the term "saccharide" as used herein may have its broadest meaning generally known in the art.

[0024] The saccharide (S) of the matrix material (MA) contained in the embedded product may contain one carbohydrate unit or two or more carbohydrate units, which may be identical to each other or independently different. By way of example, a saccharide containing two carbohydrate units is called a disaccharide, a saccharide containing two similar carbohydrate units is called a homodisaccharide, and a saccharide containing two different carbohydrate units is called a heterodisaccharide. The carbohydrate units may be substituted to adjust the hydrophilicity of the saccharide (S).

[0025] Preferably, the sugars (S) of the matrix material (MA) contained in the embedding product are hydrophilic, as defined above.

[0026] As defined above, the sugars (S) of the matrix material (MA) contained in the embedding product may also contain one or more carbohydrate units containing 5 or 6 carbon atoms, called pentoses and hexoses, respectively.

[0027] Non-limiting examples of pentoses include those having at least one halo, C 1-6 Alkyl or C 1-6 Mention may be made of ribose, arabinose, arabulose, lyxose, likylose, ribulose, xylose and xylulose, which may be substituted with alkoxy substituents.

[0028] Non-limiting examples of hexoses include those having at least one halo, C 1-6 Alkyl or C 1-6 Mention may be made of allose, altrose, fructose, galactose, glucose, gulose, idose, mannose, psicose, sorbose, tagatose and talose, which may be substituted with alkoxy substituents.

[0029] According to a preferred embodiment of the invention, the sugars (S) of the matrix material (MA) comprised in the embedding product are selected from the group consisting of monosaccharides and disaccharides.

[0030] Preferred monosaccharides are selected from the group consisting of glucose, mannose, fructose, galactose, ribose, arabinose and xylose, more preferably the saccharide (S) is selected from the group consisting of glucose, mannose and fructose.

[0031] Preferred disaccharides are selected from the group consisting of sucrose, lactose, maltose, trehalose and cellobiose, more preferably from the group consisting of sucrose, lactose and maltose, with sucrose being especially preferred.

[0032] According to a more preferred embodiment of the invention, the sugars (S) of the matrix material (MA) contained in the embedding product are selected from the group consisting of glucose, mannose, fructose and sucrose, with sucrose being particularly preferred.

[0033] The matrix material (MA) may further comprise at least one additional compound, provided that said at least one additional compound does not interfere with the embedding properties of the sugars (S), as detailed above, and provided that the amount of the at least one additional compound, expressed as wt.% relative to the total weight of the matrix material (MA), is lower than the amount of sugars (S) in the matrix material (MA).

[0034] Within the context of the present invention, the expression "at least one additional compound" is intended to denote one additional compound or two or more additional compounds, said additional compounds being capable of being used as antioxidants, colorants or stabilizers.

[0035] In the remainder of the text, the expression "additional compounds" is understood for the purposes of the present invention both in the plural and in the singular, i.e. that the matrix material (MA) in the embedding product according to the invention further comprises one additional compound or two or more additional compounds.

[0036] Non-limiting examples of suitable additional compounds may include inert additional compounds such as silicon dioxide, butylated hydroxytoluene (BHT), bisphenol A-bis(diphenyl phosphate) (BDP), or non-saccharide-based additional compounds such as polyvinyl alcohol (PVA).

[0037] According to a preferred embodiment of the invention, the amount of sugars (S) in the matrix material (MA) of the embedded product is 60.0 wt.% or more, preferably 70.0 wt.% or more, preferably 80.0 wt.% or more, more preferably 90.0 wt.% or more, more preferably 95.0 wt.% or more, more preferably the matrix material consists essentially of sugars (S) as defined above, based on the total weight of the matrix material.

[0038] Within the context of the present invention, the term "consisting essentially of sugars (S)" is to be understood as meaning that any additional components, different from sugars (S) contained in the matrix material (MA), as defined above, are present in an amount of up to 1.0 wt.%, or up to 0.5 wt.%, or up to 0.1 wt.%, relative to the total weight of the matrix material.

[0039] As mentioned above, the embedded product of the present invention comprises at least 60.0 wt.% of matrix material (MA) based on the total weight of the embedded product.

[0040] Preferably, the embedded product of the invention comprises at least 65.0 wt.%, or at least 70.0 wt.%, or at least 75.0 wt.%, or at least 80.0 wt.% matrix material (MA) based on the total weight of the embedded product.

[0041] It is further understood that the upper limit of the amount of matrix material (MA) is not particularly limited, but is advantageously 99.0 wt.% or less, or 97.0 wt.% or less, or 95.0 wt.% or less of matrix material, based on the total weight of the embedded product.

[0042] The inventors have found that in order for the matrix material (MA) as detailed above, and in particular the sugars (S) as detailed above, to fulfil their embedding role, it is further required that the molar ratio of sugars (S) to the at least one lanthanide, actinide or compound thereof in the embedded product is greater than 1.5, preferably 1.8 or more, more preferably 2.0 or more, even more preferably 4.0 or more.

[0043] It is further understood that the upper limit of the molar ratio of sugars (S) to at least one lanthanide, actinide, or compound thereof is not particularly limited, but is advantageously less than 15.0, or less than 13.0, or less than 10.0.

[0044] Within the context of the present invention, the expression "at least one lanthanide, actinide, or compound thereof" is intended to indicate "one lanthanide or two or more lanthanides, or one actinide or two or more actinides, or one compound thereof, or two or more compounds thereof." Mixtures of lanthanides, mixtures of actinides, or mixtures of their compounds may be used.

[0045] In the remainder of the text, the expressions "lanthanides", "actinides" and "compounds thereof" are to be understood for the purposes of the present invention in both the plural and the singular.

[0046] The lanthanides, actinides, or compounds thereof defined above may be commercially available, may be derived from certified reference materials such as NBL PO CRM 116-A enriched uranium or CETAMA MP 2 plutonium reference materials, or may be prepared using conventional methods known to those skilled in the art, such as the use of standard solutions or dissolution of standard metals or compounds thereof, or may be derived from field samples, such as environmental, biological, or food field samples.

[0047] Where the lanthanides, actinides or compounds thereof, as defined above, are commercially available or prepared using conventional methods, the embedded product according to the invention preferably consists essentially of the matrix material (MA) and the lanthanides, actinides or compounds thereof, as detailed above.

[0048] If the lanthanides, actinides, or compounds thereof are derived from a field sample, the field sample may be sampled and prepared according to any technique known to those skilled in the art, for example by techniques for taking environmental swipe samples in nuclear protection devices, or by taking samples in the context of radiation protection, or by sampling vegetation, soil or water, or clinical samples, as described in IAEA SAFEGUARDS GLOSSARY 2001, June 2002 IAEA / NVS / 3, which is incorporated herein by reference. As detailed above, if at least one lanthanide, actinide, or compound thereof is derived from a field sample, it goes without saying that the embedding material may further comprise impurities in an amount of less than 10.0 wt.%, less than 1.0 wt.%, or 0.5 wt.% or less, based on the total weight of the embedding product, the nature of the impurities depending on the sampling technique.

[0049] The lanthanides, actinides, or compounds thereof in the embedding material according to the invention include all known isotopes of said lanthanides, actinides, or compounds thereof, said isotopes may be radioactive or non-radioactive.

[0050] Non-limiting examples of lanthanides include lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), promethium (Pm), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), and ytterbium (Yb).

[0051] Preferably, the lanthanide is selected from the group consisting of cerium (Ce), samarium (Sm), europium (Eu), gadolinium (Gd), and terbium (Tb).

[0052] Non-limiting examples of actinides include actinium (Ac), thorium (Th), proactinium (Pa), uranium (U), neptunium (Np), plutonium (Pu), americium (Am), curium (Cm), berkelium (Bk), californium (Cf), einsteinium (Es), fermium (Fm), mendelevium (Md), nobelium (No), and lawrencium (Lr).

[0053] Preferably, the actinide is selected from the group consisting of uranium (U) and plutonium (Pu).

[0054] The expression "compound of a lanthanide or actinide" as used herein may have the broadest meaning generally understood in the art of the form in which such a compound may exist, and may include in particular salts, oxides, carbides, complexes thereof or mixtures thereof, and said lanthanide or actinide in said compound of a lanthanide or actinide may be in any oxidation state known to a person skilled in the art.

[0055] Advantageously, the counterions of said salts are selected from among the halides, nitrates, sulfates, carbonates and hydroxides.

[0056] Non-limiting examples of such salts include cerium nitrate, iron (II) chloride, gadolinium hydroxide, gadolinium chloride, gadolinium sulfate, gadolinium nitrate, americium chloride, americium nitrate, uranium hexafluoride, uranyl nitrate, plutonium nitrate, plutonyl nitrate, uranyl sulfate, uranyl sulfate, plutonium sulfate, and plutonyl sulfate.

[0057] The most preferred salts are actinide salts such as uranyl nitrate, plutonium nitrate, plutonyl nitrate, uranium sulfate, uranyl sulfate, plutonium sulfate, plutonyl sulfate, etc. Uranyl nitrate and plutonium nitrate are especially preferred.

[0058] Non-limiting examples of said oxides may include americium oxide, uranium oxide, and plutonium oxide.

[0059] Non-limiting examples of such complexes may include gadolinium chelates, uranocene and cyclooctatetraene and cyclopentadiene complexes.

[0060] Non-limiting examples of said carbides include uranium carbide, thorium carbide, plutonium carbide, neodymium carbide, gadolinium carbide and samarium carbide.

[0061] Method for producing embedded products As detailed above, a method for producing the embedded product is also an aspect of the present invention.

[0062] It is further understood that all of the above definitions, preferences and preferred embodiments also apply to all further embodiments, as described below.

[0063] The embedded products of the invention can be prepared by various methods known in the art. Several methods can be suitably used to manufacture the embedded products.

[0064] In one embodiment of the invention, the method for producing an embedded product, as detailed above, comprises first contacting a matrix material (MA), as detailed above, with at least one lanthanide, actinide, or compound thereof, as detailed above.

[0065] It is understood that the contacting can be carried out by any method known to those skilled in the art according to common practice.

[0066] According to a preferred embodiment of the method for producing an embedded product of the present invention, the matrix material (MA) is intimately mixed with at least one lanthanide, actinide, or compound thereof.

[0067] Intimate mixing can be accomplished using conventional mixers and blenders, high density mixers and electric stirrers.

[0068] It is further understood that any sequence of intimate mixing of the matrix material (MA) with one of the lanthanides, actinides, or compounds thereof, as detailed above, is permissible, and that the skilled person will carry out said intimate mixing according to common practices, including, among other things, using optimal times, speeds, as well as weights, volumes, and batch amounts.

[0069] Optionally, the matrix material (MA) and at least one lanthanide, actinide, or compound thereof as detailed above can be first intimately mixed as detailed above, thereby forming a first premix, which is then further subjected to an acidification step followed by a drying step.

[0070] The first premix acidification step can be carried out in a technically simple, environmentally and economically viable manner by using small amounts of acid, as detailed above. Such small amounts of acid used during acidification have the advantage that the drying time can be reduced while still providing an excellent embedded product. Moreover, it has been found that such small amounts of acid allow the embedded product to be produced in a more reproducible manner by limiting the influence of laboratory conditions such as humidity, drying temperature and time.

[0071] The inventors have also found that the acidification step of the first premix before drying according to the method of the invention further improves the stability of the embedded product, which therefore exhibits superior transport, storage and / or handling of the lanthanides, actinides or compounds thereof.

[0072] It has been found in practice that the first premix acidification step according to the method of the invention, when carried out in a glass vial, allows the formation of the embedded product in the form of a foam, which adheres to the inner wall of the glass vial. As a result, the adhesion of the embedded product limits the detachment of the embedded material and facilitates its transport.

[0073] In addition to the improved stability of the embedded product, as detailed above, the embedded product also exhibits excellent homogeneity. Without being bound by this theory, it is speculated that the formation of the embedded product in the form of a foam allows the lanthanide, actinide or compound thereof to be uniformly distributed in the matrix material (MA) prior to the drying step of the method of the invention, as detailed above.

[0074] The acidification step according to the method for producing an embedded product of the present invention can be carried out by any method or technique known to those skilled in the art, following common practices, such as using in particular optimal pH, time, temperature, pressure, volume and batch size.

[0075] Suitable acidification may include acidic solutions such as solutions of hydrochloric acid and nitric acid.

[0076] Preferably, the first premix is ​​acidified by an acidic solution, whereby the acidified first premix obtained has a pH value of 0.0-7.0, more preferably 0.1-5.0, more preferably 0.5-4.0, more preferably 1.0-3.0.

[0077] Preferably, the first premix is ​​acidified with a nitric acid solution. More preferably, the first premix is ​​acidified with a nitric acid solution, said nitric acid solution having a concentration of 1M to 8M.

[0078] As detailed above, drying of the first premix results in the removal of any residual water present, thereby providing improved embedding of the one lanthanide, actinide or compound thereof, as detailed above, in the matrix material (MA), as detailed above.

[0079] It is understood that drying is advantageously carried out, as detailed above, until the embedded product of the invention is substantially free of water, i.e. until it contains at most 10.0 wt.%, or at most 5.0 wt.%, or at most 1.0 wt.% water relative to the total weight of the embedded product.

[0080] Drying may be carried out by any method or technique known to those skilled in the art, following common practices such as using optimum times, temperatures, pressures, volumes and batch sizes.

[0081] Suitable methods or techniques of drying include heat drying at atmospheric pressure, reduced pressure or pressure (e.g. when drying is carried out in a glove box), hot air drying, drying under reduced pressure, infrared drying, freeze drying, high humidity drying using hot water vapor, etc. Preferably, heat drying is used.

[0082] It will be appreciated that drying is carried out at a temperature below the decomposition temperature of any of the components of the embedded product as detailed above, such as a temperature of from 30°C to 150°C, or from 40°C to 100°C, or from 50°C to 90°C.

[0083] Alternatively, the matrix material (MA) and at least one lanthanide, actinide, or compound thereof can be combined in a vessel, thereby obtaining a mixture (M), which is then subjected to a heating step.

[0084] It is understood that any container known to one of skill in the art, such as a glass vial, can be used in the context of the present invention.

[0085] Without wishing to be bound by this theory, it is speculated that the heating step promotes melting of the matrix material (MA), thus enabling the matrix material (MA) to embed at least one lanthanide, actinide, or compound thereof in a homogeneous manner.

[0086] Suitable methods or techniques of heating include dry heating at atmospheric pressure, reduced pressure or pressure (e.g., when the heating is carried out in a glove box), hot air heating, infrared drying, high humidity heating using hot water vapor, etc. Preferably, dry heating at atmospheric pressure, reduced pressure or pressure is used.

[0087] It will be appreciated that heating is carried out at a temperature below the decomposition temperature of any of the components of the embedded product as detailed above, such as a temperature of from 30°C to 150°C, or from 40°C to 100°C, or from 50°C to 90°C.

[0088] If desired, prior to the heating step, mixture (M) is subjected to an acidification step as detailed above.

[0089] Another aspect of the present invention is a method for determining the concentration of at least one analyte in a sample (hereinafter sample (SA)), wherein the analyte is selected from the group consisting of at least one lanthanide, actinide or compound thereof, as detailed above, said method comprising spiking sample (SA) with an embedding material, as detailed above.

[0090] It is further understood that all of the definitions and preferences set forth above apply equally to all further embodiments, as described below.

[0091] Within the context of the present invention, the expression "at least one analyte" is intended to denote one analyte or two or more analytes.

[0092] In the remainder of the text, the expression "analytes" is to be understood for the purposes of the present invention both in the plural and in the singular.

[0093] Within the context of the present invention, the term "spike" or "spiking" refers to its meaning as known in the art. In particular, spiking is known to those skilled in the art to refer to the addition of a known amount or concentration of an analyte contained in a spike material to the sample to be analyzed. This allows the analyte to be quantified by calibration.

[0094] In other words, a known amount or concentration of at least one lanthanide, actinide, or compound thereof contained in an embedding product (ie, spiked material) is added to a sample (SA) as defined above.

[0095] As detailed above, the inventors have found that when the embedding material of the present invention is used to spike a sample (SA) in a method for determining the concentration of an analyte in the sample (SA), said embedding material enables a quantitative and highly accurate determination of the concentration of said analyte in the sample (SA).

[0096] Suitable samples (SA) may include environmental, biological or food sector samples.

[0097] Non-limiting examples of environmental field samples can include environmental swipes, wipes, and field samples derived from soil.

[0098] A non-limiting example of a biological field sample may include a field sample derived from vegetation.

[0099] Non-limiting examples of food sector samples include field samples derived from industrial areas.

[0100] Preferably, the sample (SA) of the method for determining the concentration of an analyte of the present invention is selected from the group consisting of environmental field samples derived from environmental swipes, wipes and soil.

[0101] According to a preferred embodiment of the method for determining the concentration of an analyte in a sample (SA), the lanthanides, actinides or compounds thereof are further analyzed by mass spectrometry.

[0102] Any mass spectrometry technique known to one of skill in the art for determining the concentration of an analyte in a sample (SA) in which the sample (SA) is spiked can be used.

[0103] Non-limiting examples of mass spectrometry techniques for determining the concentration of an analyte in a sample (SA) may include isotope dilution thermal ionization mass spectrometry (ID-TIMS), chemical ablation thermal ionization mass spectrometry (CA-TIMS), and multi-collector inductively coupled plasma mass spectrometry (MC-ICP-MS), sector field ICP-MS, or laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS).

[0104] Preferably, the sample (SA) is analyzed by isotope dilution thermal ionization mass spectrometry (ID-TIMS) or multi-collector inductively coupled plasma mass spectrometry (MC-ICP-MS), more preferably by isotope dilution thermal ionization mass spectrometry (ID-TIMS).

[0105] It is understood that those skilled in the art will carry out the techniques according to common practices, including, inter alia, using optimal times, speeds, weights, volumes and batch sizes.

[0106] The inventors have also found that when an embedding material is used in the method for determining the concentration of an analyte in a sample (SA) according to the present invention, said embedding material does not cause undesired interference through positive or negative bias.

[0107] Furthermore, the inventors have found that the embedding products of the methods for determining the concentration of an analyte of the present invention comply with the requirements set out in international document standards such as the ISO standards ISO 17025:2017 and ISO 17034:2016.

[0108] Another aspect of the invention is the use of an embedding product as detailed above in a method for determining the concentration of an analyte in a sample (SA) as detailed above.

[0109] It is further understood that all of the definitions and preferences set forth above apply equally to all further embodiments, as described below.

[0110] Another aspect of the invention is the use of an embedding product as detailed above as a reference material, in particular as a certified reference material.

[0111] It is further understood that all of the definitions and preferences set forth above apply equally to all further embodiments, as described below. EXAMPLES

[0112] The invention will now be described in more detail, for purposes of illustration only and without the intention of limiting the scope of the invention.

[0113] Raw materials: The following materials were purchased commercially and used in the experiments without purification: D-(+)-sucrose (Merck, Darmstadt, Germany), D-(+)-glucose (Merck), D-(+)-mannose (≥99.5%, VWR, Leuven, Belgium), D-(-)-fructose (Molekula, Munich, Germany), SiO2 (VWR), Ce(NO3).6H2O (Sigma-Aldrich, Overijse, Belgium).

[0114] UO2(NO3)2 was prepared in-house by dissolving a known amount of certified uranium ingot (EC NRM 101, Geel, Belgium and NBL PO CRM 116-A Lemont, USA) in approximately 6 M nitric acid (Merck) solution followed by evaporation of the solvent at 55–60 °C.

[0115] Pu(NO3)4 was prepared in-house by dissolving a known amount of certified plutonium ingot (CETAMA MP2, CEA Marcoule, France) in approximately 6 M hydrochloric acid solution (Suprapur®, Merck) followed by evaporation of the solvent at 55–60 °C.

[0116] General procedure for the preparation of the embedded products (C) of Examples 1 to 5 and 8 (E1 to E5 and E8) and Comparative Examples CE1 to CE3: Each of the embedded products of Examples 1-5 (E1-E5) and Comparative Example CE1 was prepared by intimately mixing the sugar (S) (essentially and in the amount) listed in Table 1 in a vial containing the lanthanide, actinide, or compound thereof (essentially and in the amount) listed in Table 1. A few drops of a 2M solution of HNO3 were added to each vial. The solution or mixture was heated to a temperature above room temperature but below the decomposition point of any of the compounds of the embedded product, and the solvent was allowed to evaporate until a foam was formed and no condensation was observed on the inside walls of the vial.

[0117] Each of the embedded products of Example 8 (E8) and Comparative Examples CE2 and CE3 was prepared by intimately mixing the sugar (S) and additional compounds (essentially and in amounts) listed in Table 2 in a vial containing the lanthanide, actinide, or compound thereof (essentially and in amounts) listed in Table 2. A few drops of a 2M solution of HNO3 were added to each vial. The solution or mixture was heated to a temperature above room temperature and below the decomposition point of any of the compounds of the embedded product, and the solvent was allowed to evaporate until a foam was formed and no condensation was observed on the inside walls of the vial.

[0118] Evaluation of the stability and homogeneity of the embedded products of Examples 1 to 5 and 8 (E1 to E5 and E8) and Comparative Examples CE1 to CE3: The embedded products according to Examples 1 to 5 and 8 (E1 to E5 and E8) and Comparative Examples 1 to 3 (CE1 to CE3) were prepared according to the general procedure.

[0119] Due to the radioactivity of UO2(NO3)2 and Pu(NO3)4, Examples 1 and 2 (E1-E2) and Comparative Example 1 (CE1) were dried in a glove box under slight pressure (approximately 70 mbar).

[0120] Examples 3-5 and 8 (E3-E5 and E8) and Comparative Examples 2-3 (CE2-CE3) were dried under atmospheric pressure.

[0121] It is assumed that the pressure difference of the embedded products according to Examples 1-2 (E1-E2) and Comparative Example 1 (E1), as well as Examples 3-5 and 8 (E3-E5 and E8) and Comparative Example 2-3 (CE2-CE3), does not substantially affect the drying time of the embedded products.

[0122] The stability and homogeneity of each of the embedded products of Examples E1-E5 and E8 and Comparative Examples CE1-CE3 were evaluated.

[0123] Stability was assessed by visual means of the embedded products in the vials over a period of up to 3 years. The absence of peeling of the embedded product and the absence of cracking over time indicate excellent stability of the embedded product and are indicated by a "+" sign in Tables 1 and 2. Conversely, the presence of peeling and / or cracking of the embedded product are indicated by a "-" sign in Tables 1 and 2.

[0124] Homogeneity was also assessed by visual means of the embedded products in the vials. The homogeneity of the structure of the products, their color and potential aggregate formation at a macroscopic level were examined. The absence of color inconsistencies and / or aggregate formation, which indicates a good homogeneity of the embedded products, is indicated by a "+" sign in Tables 1 and 2. Conversely, the presence of color inconsistencies and / or aggregate formation in the embedded products is indicated by a "-" sign in Tables 1 and 2. [Table 1] [Table 2]

[0125] The results in Table 1 show that embedding products consisting of sucrose as matrix material (MA) and uranyl nitrate (UO2(NO3)2) and plutonium nitrate (Pu(NO3)4) in amounts according to the invention show good stability and good homogeneity over periods of up to 3 years (examples E1 and E2).

[0126] In contrast, the embedded product according to Comparative Example CE1, which has a molar ratio of sucrose (S) to uranyl nitrate (UO2(NO3)2) and plutonium nitrate (Pu(NO3)4) of 1.4 and is therefore outside the scope of the claims, resulted in its delamination within one year, indicating its poor stability. Also, the orange color of the sample was not uniform in nature, indicating an uneven distribution of the embedded product.

[0127] The results in Table 1 further demonstrate that a wide variety of sugars (S) according to the present invention, i.e. sucrose, fructose, mannose, and glucose, as well as a wide variety of compounds of lanthanides, actinides, or compounds thereof, can be used without compromising the stability and homogeneity of the embedded product.

[0128] The results in Table 2 show that when the embedded product consists of sucrose as the sugar (S), silicon dioxide (SiO2) as additional compounds, and Ce(NO3)3.6H2O, it showed excellent stability and homogeneity when the amount of sugar (S) in the matrix material (MA) was within the claimed range (E8).

[0129] In contrast, when the amount of sugar (S) in the embedded products relative to the total weight of the matrix material (MA) was outside the claimed range (CE2: 21 wt.% and CE3: 51 wt.%), the embedded products showed either incomplete embedding or partial exfoliation within a few days, indicating poor stability. Moreover, the formation of aggregates was observed at the macroscopic level.

Claims

1. 1. An embedded product suitable for transporting, storing and / or handling a lanthanide, an actinide, or a compound thereof, said embedded product comprising, based on the total weight of said embedded product: - at least 60.0% by weight (wt.%) of a matrix material (MA), said matrix material (MA) comprising more than 55.0 wt.% of at least one sugar selected from the group consisting of monosaccharides, disaccharides, trisaccharides and tetrasaccharides (hereinafter sugars (S)) relative to the total weight of said matrix material (MA); at least one lanthanide, actinide or compound thereof, Including, An embedded product, wherein the molar ratio of the sugars (S) to the at least one lanthanide, actinide, or compound thereof in the embedded product is greater than 1.

5.

2. 2. The embedded product of claim 1, wherein the sugar (S) is selected from the group consisting of monosaccharides and disaccharides, preferably selected from the group consisting of glucose, mannose, fructose and sucrose, more preferably the sugar (S) is sucrose.

3. 2. The embedded product according to claim 1, wherein the amount of the sugar (S) relative to the total weight of the matrix material is 60.0 wt.% or more, preferably 70.0 wt.% or more, preferably 80.0 wt.% or more, more preferably 90.0 wt.% or more, and more preferably the matrix material consists essentially of the sugar (S).

4. 2. The embedded product according to claim 1, wherein the embedded product comprises at least 65.0 wt.%, or at least 70.0 wt.%, or at least 75.0 wt.%, or at least 80.0 wt.% of the matrix material (MA) relative to the total weight of the embedded product.

5. 2. The embedded product of claim 1, wherein the molar ratio of sugars (S) to the at least one lanthanide, actinide, or compound thereof in the embedded product is 1.8 or greater, more preferably 2.0 or greater, and even more preferably 4.0 or greater.

6. 2. The embedded product of claim 1, wherein the embedded product consists essentially of the matrix material (MA) and the at least one lanthanide, actinide, or compound thereof.

7. 2. The embedded product of claim 1, wherein the at least one lanthanide is selected from the group consisting of cerium (Ce), samarium (Sm), europium (Eu), gadolinium (Gd) and terbium (Tb), the at least one actinide is selected from the group consisting of uranium (U) and plutonium (Pu), and the at least one compound is selected from the group consisting of uranyl nitrate, plutonium nitrate, plutonyl nitrate, uranium sulfate, uranyl sulfate, plutonium sulfate and plutonyl sulfate.

8. 8. A method for producing an embedded product according to any one of claims 1 to 7, comprising the step of contacting said matrix material (MA) with said at least one lanthanide, actinide or compound thereof.

9. 9. The method of claim 8, wherein the matrix material (MA) and the at least one lanthanide, actinide, or compound thereof are intimately mixed to form a first premix, and then the first premix is ​​further subjected to an acidification step and then a drying step.

10. 10. The method of claim 9, wherein the first premix is ​​acidified with a nitric acid solution, preferably with a nitric acid solution at a concentration of 1M to 8M.

11. 9. The method of claim 8, wherein the matrix material (MA) and the at least one lanthanide, actinide, or compound thereof are combined in a container, thereby providing a mixture (M), and then the mixture (M) is subjected to a heating step.

12. 8. A method for determining the concentration of at least one analyte contained in a sample (hereinafter sample (SA)), wherein the at least one analyte is selected from the group consisting of at least one lanthanide, actinide, or compound thereof, the method comprising spiking the sample (SA) with the embedding material according to any one of claims 1 to 7.

13. 13. The method of claim 12, wherein said sample (SA) is selected from the group consisting of environmental field samples derived from environmental swipes, wipes, and soil.

14. 13. The method of claim 12, wherein the at least one lanthanide, actinide, or compound thereof is further analyzed by mass spectrometry.

15. 15. The method of claim 14, wherein the at least one lanthanide, actinide, or compound thereof is analyzed by isotope dilution thermal ionization mass spectrometry (ID-TIMS).