Device and method for concentrating plastic particles and / or organic matter present in a sample comprising an unconsolidated solid matrix

Abstract

The invention relates to a device and a method for superconcentrating a sample comprising plastic particles and / or organic matter in an unconsolidated solid matrix to a predefined superconcentration rate. The device comprises a first (10), a second (20) and a third chamber (30), controllable opening and closing means (23) for a first opening of the second chamber (20) or a second opening (12) of the first chamber (10), and controllable opening and closing means (24) for a second opening (22) of the second chamber (20), and means for connecting (15, 16, 26, 25, 25', 26', 35, 36) the chambers (10, 20, 30) to each other. Furthermore, according to the invention, a ratio between, firstly, the sum of the volumes of the second chamber and the third chamber, and secondly, the volume of the second chamber, is equal to the predefined overconcentration rate. Figure 1 to be published.

Description

Title of the invention: Device and method for concentrating plastic and / or organic matter particles present in a sample comprising an unconsolidated solid matrix technical field

[0001] The present invention may relate to the field of monitoring plastic waste present in the environment, such as in soils, sediments or muds, in a marine, river or lake environment, or even in the ambient air.

[0002] The present invention may also relate to the field of geosciences, in particular the field of exploration and exploitation of petroleum deposits, or even the field of environmental science.

[0003] More specifically, the present invention aims to concentrate plastic particles and / or organic matter present in a sample comprising an unconsolidated solid matrix, for example for the purpose of analyzing the microplastic and / or organic matter content of this sample.

[0004] The use of plastics (polymer-based materials) has been developing for many years in global industry. Today, traces of these polymers are found almost everywhere on Earth, particularly in soils, rivers, seas, glaciers, oceans, and the atmosphere. They constitute an increasingly significant form of pollution.

[0005] Moreover, these plastics can end up in the environment in a microscopic form, invisible to the human eye, but nevertheless generate significant pollution for fauna and flora.

[0006] Moreover, these plastics can transform in the environment, through physical or chemical phenomena and thus create compounds which are called "neoformed", that is to say, which only exist through the presence of polymers in the environment.

[0007] According to some classifications, microplastics are defined as particles of any type of polymer with sizes less than 5 mm and greater than 1 µm, while mesoplastics have particle sizes between 5 mm and 25 mm. Due to their small size and low density, meso- and microplastics can be easily transported by water currents or even by wind, and are found in all types of environments, including ambient air, soils, waterways, sediments, and also in the sea.

[0008] Today the characterization of the marine, river or lake environment, but also the characterization of soils and sediments or even ambient air, is important to assess the current level of pollution of our environment by plastics, but also to allow us to assess the evolution of this pollution over time.

[0009] The methods conventionally used for the detection and / or characterization of plastic particles most often require that the plastic particles be present in the analyzed sample at a concentration high enough to be compatible with the detection limits of these methods and / or the instruments used by these methods. Among these analytical methods, examples include thermal extraction-desorption coupled with gas chromatography and mass spectrometry, pyrolysis coupled with gas chromatography, Fourier transform infrared spectroscopy, mass spectrometry, and Raman spectroscopy.

[0010] For example, French patent application FR 21 / 05123 A1 (application number), which relates to a method for characterizing the presence and / or quantifying at least one polymer in a porous medium, using quantities of hydrocarbon compounds and / or CO and / or CO2 measured during a heating sequence under an inert atmosphere followed by a heating sequence under an oxidizing atmosphere, requires concentrations greater than 0.2% by weight of the analyzed sample in order to generate a signal identifiable by the device. This detection limit is sufficient for many natural cases; however, it does not cover all the concentrations encountered in the environment, particularly when these are very low.

[0011] In the field of petroleum geosciences or environmental sciences, the methods classically used for the detection and / or characterization of organic matter also require that the particles of organic matter be present in the sample analyzed in a concentration high enough to be compatible with the detection thresholds of these methods and / or the devices used by these methods.

[0012] Among these methods, examples include patents EP0691540A1, US10088465A1, and WO2022 / 200091A1, which relate to processes for characterizing organic matter from reservoir rock, source rock, or soil, respectively, by means of quantities of hydrocarbon compounds and / or CO and / or CO2 measured during a heating sequence under an inert atmosphere followed by a heating sequence under an oxidizing atmosphere. These methods require organic matter concentrations greater than 0.1% by weight, which necessitates preparing samples with a concentration lower than 0.1% by weight. acid attacks to eliminate the mineral matrix and thus relatively increase the proportion of organic matter. Previous technique

[0013] The following documents will be cited during the description:

[0014] Bellasi et al. (2021) The extraction of microplastics from sédiments: an overview of existing methods and the proposai of a new and green alternative https: / / doi.Org / 10.l 016 / j. chemo sphere .2021.130357.

[0015] Coppock et al. (2017) A small-scale, portable method for extracting microplastics from marine sédiments https: / / doi.Org / 10.1016 / j.envpol.2017.07.017.

[0016] Nakajima et al. (2019) A new small device made of glass for separating microplastics from marine and freshwater sédiments DOI 10.7717 / peerj.7915.

[0017] Paradinas et al. (2021) A New Collection Tool-Kit to Sample Microplastics From the Marine Environment (Sédiment, Seawater, and Biota) Using Citizen Science doi: 10.3389 / fmars.2021.657709.

[0018] Documents relating to devices and / or methods for separating microplastics from a sample are known, such as patent application EP3272421 Al, and the documents (Bellasi et al., 2021; Coppock et al., 2017; Nakajima et al., 2019; Paradinas et al., 2021). More specifically, these documents describe devices and methods for separating sediments from microplastics using solutions with a density greater than that of the microplastics (such as NaCl, ZnCl2, or Nal solutions). After separation, the microplastics are suspended in the solution, the solution is collected, and the microplastics are separated from the suspension by filtration. Therefore, there are many steps involved in collecting the sample from the environment, conditioning it, and preparing it for analysis. Furthermore, the quantities of materials (sand, sediment, soil...The quantities of microplastics collected and processed must often be substantial (1 kilogram or more) to ensure that the final treated sample has concentrations compatible with the detection thresholds of methods commonly used to identify and characterize microplastics. In all cases, prior art devices cannot guarantee a predefined concentration in the final sample.

[0019] Thus, in the field of monitoring microplastic and mesoplastic waste, it may happen that the analytical methods classically used fail to characterize and / or quantify the plastic particles of a sample, due to a concentration of these particles that is too low compared to the detection threshold of these analytical methods.

[0020] The present invention overcomes these drawbacks. In particular, the invention relates to a device and a method for concentrating plastic and / or organic matter particles in a controlled manner, notably to meet the detection thresholds of analytical methods for detecting and / or characterizing mesoplastics and microplastics and / or organic matter. Furthermore, the device according to the invention is portable and easy to use. Moreover, in its preferred embodiment, the present invention allows for the preparation and packaging of samples for analysis with fewer steps compared to the prior art, thereby avoiding contamination and losses (for example, those related to the adhesion of particles to the walls of laboratory glassware or to the filters used) that could distort the analysis of plastic particles. Summary of the invention

[0021] The invention relates to a device for overconcentrating a sample comprising plastic particles and / or organic matter in an unconsolidated solid matrix according to a predefined overconcentration rate.

[0022] The device according to the invention comprises:

[0023] - a first chamber comprising a first and a second opening;

[0024] - a second chamber comprising a first and a second opening;

[0025] - a third chamber comprising at least one first opening;

[0026] - controllable opening and closing means for said first opening of said second chamber or of said second opening of said first chamber, as well as the controllable opening and closing means of said second opening of said second chamber;

[0027] - connection means configured to allow at least the connection and the disconnection of said second opening of said first chamber with said first opening of said second chamber, and the connection and disconnection of said first opening of said third chamber with said second opening of said second chamber;

[0028] Furthermore, a ratio between, on the one hand, the sum of the volume of said second chamber and the volume of said third chamber, and on the other hand, the volume of said second chamber is equal to said predefined overconcentration rate.

[0029] According to one embodiment of the invention, said controllable opening and closing means of said first opening of said second chamber or of said second opening of said first chamber, and / or said controllable opening and closing means of said second opening of said second chamber may correspond to a guillotine valve, a shovel valve, a knife valve, a ball valve, a wheel valve, or a butterfly valve.

[0030] According to one embodiment of the invention, said device may include means for closing said first opening of said first chamber, for example in the form of a cover.

[0031] According to a first embodiment of the invention, said device may further include a filter, said filter being able to be connected to said second opening of said second chamber by means of said connection means, said filter being configured to retain said plastic particles and / or organic matter as well as said unconsolidated solid matrix in said second chamber.

[0032] According to a second embodiment of the invention, said device may further comprise a fourth chamber, of a volume at least equal to said volume of said second chamber, said fourth chamber comprising a first opening which can be connected to said second opening of said second chamber by means of said connection means, and a second opening comprising a filter configured to retain said plastic and / or organic matter particles and said unconsolidated solid matrix in said fourth chamber.

[0033] The invention further relates to a method for overconcentrating a sample comprising plastic particles and / or organic matter in an unconsolidated solid matrix according to a predefined overconcentration rate, said method being implemented by means of the device as described above.

[0034] The method according to the invention comprises at least the following steps:

[0035] a) Said first chamber and said second chamber are connected together by connecting said second opening of the first chamber with said first opening of said second chamber by means of said connection means, and said first opening of said second chamber is opened by means of the controllable opening and closing means of said first opening of said second chamber or alternatively, said second opening of said first chamber is opened by means of the controllable opening and closing means of said second opening of said first chamber;

[0036] b) Said second chamber and said third chamber are connected together by connecting said second opening of said second chamber with said first opening of said third chamber by means of the connection means, and said second opening of said second chamber is opened by means of said controllable opening and closing means of said second opening of said second chamber;

[0037] c) Said sample is introduced into said first, second and third chambers connected to each other by said first opening of said first chamber and in such a way as to reach at least the said first opening of the said second chamber;

[0038] d) The said first opening of the said second chamber is closed by means of the said controllable opening and closing means of the said first opening of the said second chamber or, alternatively, the said second opening of the said first chamber is closed by means of the said controllable opening and closing means of the said second opening of the said first chamber, the excess of the said sample present in the said first chamber is removed, and the said first opening of the said second chamber is reopened by means of the said controllable opening and closing means of the said first opening of the said second chamber, or alternatively, the said second opening of the said first chamber is reopened by means of the said controllable opening and closing means of the said second opening of the said first chamber;

[0039] e) A liquid is introduced at the level of said first opening of said first chamber into said first, second and third chambers connected to each other and said first, second and third chambers connected to each other are agitated for a first predefined period, for example by means of a vibrating table, a rotary or translational agitator, an ultrasonic device, or differential or equilibrium centrifugation;

[0040] f) The said first, second and third chambers connected to each other are left to rest for a second predefined period, the said first, second and third chambers connected to each other being arranged so as to allow a gravitational flow of at least a part of the said sample from the said first chamber to the said third chamber via the said second chamber;

[0041] g) The second opening of the second chamber is closed by means of the controllable opening and closing means of the second opening of the second chamber, (at least the third chamber is disconnected from the second chamber by means of the connection means), and the super-concentrated sample is obtained in at least the second chamber.

[0042] According to one embodiment of the invention, prior to step e), a liquid can be introduced, through said first opening of said first chamber, into said first, second and third chambers connected to each other.

[0043] According to one embodiment of the invention, said method can be implemented using the device according to the first variant described above, and said method may further comprise a step h) in which: said second opening of said second chamber is connected to said filter, said second opening of said second chamber is opened by means of said controllable opening and closing means of said second opening of said second chamber, and said second chamber and said filter connected together so as to permit gravity flow of any fluid contained in said second chamber, and said second chamber is disconnected from said filter by disconnecting said second opening from said second chamber and said filter by means of said connection means.

[0044] According to one embodiment of the invention, said method can be implemented using the device according to the second variant described above, and said method may further comprise a step h') in which: said second chamber is connected to said fourth chamber by connecting said first opening of said fourth chamber to said second opening of said second chamber by means of said connecting means, said second opening of said second chamber is opened by means of said controllable opening and closing means of said second opening of said second chamber, said second and fourth chambers are arranged connected to each other so as to allow a gravitational flow of said superconcentrated sample present in said second chamber towards said fourth chamber,and the second chamber is disconnected from the fourth chamber by disconnecting the first opening from the fourth chamber and the second opening from the second chamber using the said connection means.

[0045] The invention further relates to a use of the process as described above for overconcentrating a sample comprising plastic particles and / or organic matter in an unconsolidated solid matrix according to a predefined overconcentration rate, said process being implemented by means of the device as described above. List of figures [Fig 1]

[0046] Fig. 1 illustrates an example of implementation of the device according to the invention. [Fig 2]

[0047] [Fig.2] illustrates a particular configuration of the device of [Fig.1], which can be implemented during step g) of the process according to the invention. [Fig 3]

[0048] Fig. 3 illustrates a variant implementation of the device of Fig. 1, including an additional filter. [Fig 4]

[0049] Fig. 4 illustrates another embodiment of the device of Fig. 1, comprising in addition a fourth chamber. Description of the implementation methods

[0050] The invention relates to a device and a method for superconcentrating a sample comprising plastic particles and / or organic matter in an unconsolidated solid matrix to a predefined superconcentration rate. An unconsolidated solid matrix is ​​understood to be a solid phase formed of grains or fibers not bonded together.

[0051] In other words, the invention aims to obtain a new sample (hereafter referred to as the final sample or superconcentrated sample) comprising plastic particles and / or organic matter at a higher concentration than the concentration of the input sample (hereafter referred to as the initial sample) of the device and / or process according to the invention, and at a predefined superconcentration ratio. The superconcentration ratio is understood to be the ratio between the concentration of the final sample and the concentration of the initial sample in plastic particles and / or organic matter. For implementation of the invention, it is not necessary to know the concentrations of the initial and final samples. It is sufficient to predefine the ratio of these concentrations.For example, if we predefine an overconcentration rate of 10, this means that we aim to determine, using the device and / or method according to the invention, a final sample having a concentration multiplied by a factor of 10 compared to the concentration of the initial sample.

[0052] The initial sample, which may include plastic particles in an unconsolidated solid matrix, may result from sampling in an aquatic (marine, lacustrine, fluvial), terrestrial (soil, sediments, beach, sewage sludge) or atmospheric (ambient air, atmospheric deposition) environment. The sampling may, for example, have been carried out on a beach, and the sand grains then form (at least part of) the unconsolidated solid matrix. When the initial sample results from sampling (for example, using a very fine mesh net or a sediment trap) in an aquatic environment, the unconsolidated solid matrix may correspond to sedimentary particles suspended in the water. When the sample results from sampling in ambient air, the unconsolidated solid matrix may correspond to particles suspended in the air (for example, metallic particles, soot, dust, etc.).), other than plastic particles. Depending on an implementation where sampling is carried out in aquatic or atmospheric environments, the samples may be pre-filtered (e.g. with a sieve, membrane filter, etc.) so that the water and / or air present in the sample are essentially removed.

[0053] The initial sample, which may include particles of organic matter in an unconsolidated solid matrix, may result from coring in sedimentary rock, sediment sampling, soil sampling, or sewage sludge sampling. purification etc. In the case of a solid sample such as hardened sediment, grinding could be planned upstream to result in a solid unconsolidated matrix.

[0054] The unconsolidated solid matrix itself can be of any kind and be formed of several different materials, such as quartz particles, clays, etc.

[0055] The device and method according to the invention will subsequently be described for application to plastic particles, but the same characteristics and conclusions are valid for particles of organic matter, as well as for particles of plastic and / or organic matter. Indeed, organic matter has a density similar to that of plastics, generally less than 1.7 g / cm³, which is very low compared to the density of particles in unconsolidated solid matrices, regardless of their origin.

[0056] The device according to the invention comprises at least the following elements:

[0057] - a first chamber comprising a first and a second opening;

[0058] - a second chamber comprising a first and a second opening;

[0059] - a third chamber comprising at least one first opening;

[0060] - controllable opening and closing means for said first opening of said second chamber or of said second opening of said first chamber, as well as the controllable opening and closing means of said second opening of said second chamber;

[0061] - connection means configured to allow at least the connection and the disconnection of said second opening of the first chamber with at least said first opening of said second chamber, as well as the connection and disconnection of said first opening of the third chamber with said second opening of said second chamber.

[0062] In other words, the device according to the invention comprises at least three chambers, the second chamber being able to be connected or not to the first chamber and / or to the third chamber. Hereafter, for the sake of simplicity of reading, the term "upper chamber" is also used for the first chamber, the term "intermediate chamber" for the second chamber, and the term "lower chamber" for the third chamber, the terms "upper", "intermediate" and "lower" being taken by reference to the configuration (hereafter referred to as the service position) of the device according to the invention in which the second chamber is connected to both the first and third chambers and are arranged so as to allow gravity flow from the first chamber to the second chamber and then to the third chamber.In other words, in service position, the first room is "above" the second room, which is itself "above" the third room. By connected rooms, we mean rooms where one opening is connected to an opening in another; thus, the interior volumes. The rooms are seamlessly connected to each other, allowing for the exchange of their contents from one room to another.

[0063] Furthermore, according to the invention, for a predefined overconcentration rate, the ratio between, on the one hand, the sum of the volumes of the second and third chambers, and on the other hand, the volume of the second chamber is equal to the predefined overconcentration rate, which can be written according to the formula:

[0064]

[0065] where V3 is the volume of the third chamber, V2 is the volume of the second chamber, and S is the predefined overconcentration rate. Thus, according to the invention, the volumes of the second and third chambers are a function of a target overconcentration to be achieved.

[0066] For example, if one wishes to overconcentrate the plastic particles in the solid matrix by a factor of 10 (S=10) (in other words, if one wishes to multiply the concentration of the plastic particles by 10 compared to the concentration of the initial sample), the ratio between the volume of the third chamber and the volume of the second is V3 / V2 = 9: In other words, the volume of the lower chamber is equal to 9 times the volume of the intermediate chamber, or put another way, the volume of the intermediate chamber is 9 times less than the volume of the lower chamber. Thus, if the second chamber of the device has a volume of 10 cL, the volume of the third chamber of the device has a volume of 90 cL, and vice versa.

[0067] According to one embodiment of the invention, the volume of the first chamber is greater than at least 20% of the volume of the second chamber, or in other words:

[0068] Vl>0.2*V2

[0069] where VI is the volume of the first chamber and V2 is the volume of the second chamber. As will be described below, the first chamber provides a free volume within the assembly formed by the first, second, and third chambers connected together, after step c) of the process according to the invention described below. This free volume allows for agitation of the introduced sample, especially after the introduction of a liquid that promotes agitation and sedimentation of the particles constituting the initial sample, as will be explained later. Preferably, to further facilitate agitation and / or to allow the introduction of a quantity of liquid, the volume of the upper chamber can be at least twice the volume of the second chamber. Alternatively, the volume of the upper chamber can be equal to the volume of the lower chamber. This allows for simplified manufacturing of the device according to the invention.

[0070] The method according to the invention comprises at least the following steps:

[0071] a) Said first chamber and said second chamber are connected together by connecting said second opening of the first chamber with said first opening of said second chamber by means of the connecting means, and said first opening of said second chamber is opened by means of the controllable opening and closing means of said first opening of said second chamber, or alternatively, said second opening of said first chamber is opened by means of the controllable opening and closing means of said second opening of said first chamber;

[0072] b) Said second chamber and said third chamber are connected together by connecting said second opening of the second chamber with said first opening of said third chamber by means of the connection means, and said second opening of said second chamber is opened by means of the controllable opening and closing means of said second opening of said second chamber;

[0073] c) Said sample is introduced into said first, second and third chambers connected to each other by said first opening of said first chamber and in such a way as to reach at least said first opening of said second chamber;

[0074] d) The first opening of the second chamber is closed by means of the controllable opening and closing means of the first opening of the second chamber, or, alternatively, the second opening of the first chamber is closed by means of the controllable opening and closing means of the second opening of the first chamber, then the excess of the sample present in the first chamber is removed, if applicable, and the first opening of the second chamber is reopened by means of the controllable opening and closing means of the first opening of the second chamber, or, alternatively, the second opening of the first chamber is reopened by means of the controllable opening and closing means of the second opening of the first chamber;

[0075] e) A liquid is introduced at the level of the first opening of said first chamber into said first, second and third chambers connected to each other and said first, second and third chambers connected to each other are agitated for a first predefined period, for example by means of a vibrating table, a rotary or translational agitator, an ultrasonic device, or differential or equilibrium centrifugation;

[0076] f) The said first, second and third interconnected chambers are left to rest for a second predetermined period, said first, second and third chambers connected to each other being arranged so as to allow a gravitational flow of at least a part of said sample from said first chamber to said third chamber via said second chamber;

[0077] g) The second opening of the second chamber is closed by means of the controllable opening and closing means of the second opening of the second chamber and at least the third chamber is disconnected from the second chamber by disconnecting the second opening from the second chamber and the opening from the third chamber by means of the connection means.

[0078] The method can be implemented using the device according to any of the variants or any combination of variants described above.

[0079] Thus, the device and method according to the invention are based on the fact that the particles of the unconsolidated solid matrix will undergo granular segregation resulting from the differential settling of the particles (or a sedimentation rate) of the initial sample. The plastic particles tend to remain either suspended in the introduced liquid or close to the surface of the solid matrix after agitation and settling in a (substantially) vertical position because they have a density substantially lower than that of natural mineral particles. Furthermore, the volumes of the lower and intermediate chambers are configured to allow the recovery, in the intermediate chamber, of a final sample having a predefined overconcentration compared to the initial sample.The separation of the two chambers is achieved, firstly, by means of controllable opening and closing mechanisms for the second opening of the intermediate chamber, which allow the intermediate chamber to be closed without manipulating the chamber itself (which would risk disrupting the particle size sorting process), and secondly, by means of the connection between the lower and intermediate chambers. This results in a final sample with the desired overconcentration in the intermediate chamber. Furthermore, the controllable opening and closing mechanisms for the first opening of the intermediate chamber (or, equivalently, the second opening of the upper chamber) allow the introduction into the device of any volume of the sample to be overconcentrated (provided it is at least equal to the sum of the volumes of the lower and intermediate chambers).Indeed, by means of controllable opening and closing of the first opening of the intermediate chamber (or the second opening of the upper chamber, equivalently), any excess sample that might be present in the upper chamber can be easily removed (for example, by rinsing). The protocol is thus simplified because there is no need for precise and exact measurement of the sample prior to its introduction into the device. Furthermore, this ensures... a controlled overconcentration rate in the end, because the sample volume at the input of the process according to the invention is guaranteed.

[0080] According to a highly preferred embodiment of the invention, the advantages of which will be described in more detail below, the device may further comprise a fourth chamber (hereafter referred to as the collection chamber), with a volume at least equal to the volume of the intermediate chamber. This fourth chamber comprises a first opening that can be connected to the second opening of the intermediate chamber by means of the connection means of the device according to the invention, and a second opening comprising a filter configured to retain the plastic particles and the unconsolidated solid matrix in the fourth chamber. In particular, this filter may be configured to remove any fluid present in the initial sample or added during the process according to the invention.Specifically, this filter allows for rinsing the intermediate chamber (for example, with purified water), enabling the complete transfer of the highly concentrated sample from the intermediate chamber directly to the collection chamber. By minimizing handling and ensuring complete transfer of the highly concentrated sample, this variant reduces the risk of contamination and losses (for example, those related to particle adhesion to the walls of laboratory glassware or to the filters used) that could skew the analysis of plastic particles. Furthermore, the intermediate chamber can then be used for other overconcentrations and / or for other samples.

[0081] The upper, intermediate, and lower chambers (and, where applicable, the collection chamber) of the device according to the invention may be of any shape, including different shapes, provided that the intermediate chamber can be connected to the upper and lower chambers (and, where applicable, the collection chamber) by means of the connection means according to the invention. Advantageously, the upper chamber and / or the intermediate chamber and / or the lower chamber (and, where applicable, the collection chamber) of the device according to the invention may be cylindrical or parallelepiped in shape.

[0082] Preferably, the upper chamber and / or the intermediate chamber and / or the lower chamber (where applicable, the collection chamber) may be cylindrical in shape, with the axis of revolution of the cylinder(s) being vertical in the operating position. Such a shape allows the particles constituting the sample to be concentrated (at least unconsolidated solid matrix particles and plastic particles) to adhere as little as possible to the curved walls of the chamber(s), which facilitates granular segregation and / or transfers from one chamber to another. This ultimately contributes to a more reliable subsequent quantification of the plastic particles present in the sample.

[0083] According to one embodiment of the invention, the material of the upper chamber and / or the intermediate chamber and / or the lower chamber (where applicable, the collection chamber), and of their connecting means, may be stainless steel, aluminum, or glass. Such materials limit the adhesion of the particles constituting the sample to be concentrated to the wall of the chamber(s), thereby facilitating granular segregation and / or transfers from one chamber to another. This ultimately contributes to more reliable subsequent quantification of the plastic particles present in the sample. Furthermore, such materials have the advantage of not generating extractable compounds that could interfere with any subsequent analysis aimed at quantifying and / or characterizing the plastic particles present in the sample.Alternatively, the chambers and the means of connecting them can be made of polymer materials of known composition to ensure the subtraction of this signal in case of contamination in the sample during the implementation of the process according to the invention.

[0084] According to an embodiment in which the intermediate chamber is cylindrical or parallelepiped-shaped, the first opening of the intermediate chamber may be located on the upper wall of the intermediate chamber and the second opening of the intermediate chamber may be located on the lower wall of the intermediate chamber. Preferably, the opening in the upper wall of the intermediate chamber may be located in a central part of the upper wall (for example, situated in an area centered on the centroid of the upper wall, and whose radius corresponds to 30% of the smallest dimension of the upper wall). An opening located in a central part of the upper wall of the intermediate chamber allows for a more homogeneous distribution of the particles constituting the sample compared to an off-center opening.Preferably, the first opening of the intermediate chamber substantially covers the surface of the upper wall of the intermediate chamber. Such a wide opening facilitates the introduction of the sample into the upper chamber. Advantageously, the second opening of the intermediate chamber can be positioned on the lower wall of the intermediate chamber so that its center of gravity is aligned vertically with the first opening of the upper chamber. This can facilitate the gravitational flow of the sample particles through the intermediate chamber. Preferably, the second opening of the intermediate chamber occupies substantially the surface of the lower wall of the intermediate chamber. This prevents the sample particles to be concentrated from accumulating at the bottom of the intermediate chamber.

[0085] Advantageously, the first opening of the lower chamber (respectively (the upper chamber, and where applicable, the first opening of the collection chamber) The shape and dimensions of the opening in the lower chamber (or, where applicable, the first opening in the collection chamber) can correspond to those of the second opening (located on the lower wall) of the intermediate chamber, provided that the intermediate chamber (or, where applicable, the collection chamber) is cylindrical or parallelepiped-shaped, and can be connected to the second opening (located on the lower wall) of the intermediate chamber. In an embodiment where the intermediate chamber (or, where applicable, the collection chamber) is cylindrical or parallelepiped-shaped, the opening in the lower chamber (or, where applicable, the collection chamber) can be located on the upper wall of the lower chamber (or, where applicable, the collection chamber).Preferably, the opening in the upper wall of the lower chamber (or, where applicable, the collection chamber) can be located in a central part of the upper wall (for example, in an area centered on the centroid of the upper wall, with a radius equal to 30% of the smallest dimension of the upper wall). An opening in a central part of the upper wall of the lower chamber (or, where applicable, the collection chamber) allows for a more homogeneous distribution of the sample particles compared to an off-center opening. Preferably, the first opening of the lower chamber occupies substantially the surface area of ​​the upper wall of the lower chamber (or, where applicable, the collection chamber).Such a wide opening facilitates the passage of the sample from the intermediate chamber into the lower chamber (or, where applicable, the collection chamber). Advantageously, the opening of the lower chamber (or, where applicable, the collection chamber) can be positioned so that its center of gravity is aligned with the first and second openings of the intermediate chamber along a vertical axis. This can facilitate the gravitational flow of the sample particles through the intermediate chamber into the lower chamber (or, where applicable, the collection chamber).

[0086] Advantageously, since the second opening of the upper chamber can be connected to the first opening (located on the upper wall) of the intermediate chamber by means of the connecting means, the shape and dimensions of the second opening of the upper chamber can correspond to those of the first opening (located on the lower wall) of the intermediate chamber. In an embodiment where the intermediate chamber is cylindrical or parallelepiped-shaped, the second opening of the upper chamber can be located on the lower wall of the upper chamber. Preferably, the opening in the lower wall of the upper chamber can be located in a central part of the lower wall (for example, situated in an area centered on The center of gravity of the lower wall, and whose radius corresponds to 30% of the smallest dimension of the lower wall. An opening in the central part of the lower wall of the upper chamber allows for a more homogeneous distribution of the particles constituting the sample compared to an off-center opening. Preferably, the second opening of the upper chamber occupies approximately the surface area of ​​the lower wall of the upper chamber. Such a wide opening facilitates the passage of the sample from the upper chamber into the intermediate chamber. Advantageously, the opening of the upper chamber can be positioned so that its center of gravity is aligned with the first and second openings of the intermediate chamber along a vertical axis and preferably with the first opening of the lower chamber.This can facilitate the agitation of the sample constituents during step e) of the process according to the invention, as well as facilitate the gravity flow of the sample constituent particles during step f) of the process according to the invention.

[0087] According to the invention, the first opening of the intermediate chamber or the second opening of the first chamber, equivalently, comprises controllable opening and closing means. The purpose of these controllable opening and closing means is, in particular, to allow the intermediate chamber or the upper chamber to be closed during step d) of the process according to the invention, in order to remove any excess sample that may be present in the upper chamber (for example, by rinsing). Thus, it is not necessary to precisely measure the quantity of sample to be introduced into the device during step c) of the process according to the invention. Furthermore, this ensures a controlled overconcentration rate at the end, since the sample volume entering the process according to the invention is guaranteed.

[0088] According to the invention, the second opening of the intermediate chamber comprises controllable opening and closing means. The objective of these controllable opening and closing means is, in particular, to allow the intermediate chamber to be closed after step g) of the process according to the invention, without manipulation that could cause the intermediate chamber to move and that could disrupt the natural particle size sorting performed by the particles of the unconsolidated solid matrix.

[0089] According to one embodiment of the invention, the controllable opening and closing means for the intermediate chamber and / or the upper chamber may correspond to a guillotine valve, a shovel valve, a knife valve, a ball valve, a handwheel valve, a butterfly valve, or even a rotary or translational separation system. Preferably, the closing means correspond to A guillotine valve. Such a valve allows fluids or granular materials to be separated while ensuring a tight seal.

[0090] According to the invention, the device includes connection means configured to allow at least the connection of the second opening of the upper chamber with at least the first opening of the intermediate chamber, and the connection of the second opening of the intermediate chamber with the first opening of the lower chamber.

[0091] According to one embodiment of the invention, the connection means may consist of screwing means (threaded connection), snap-fit ​​means, or sliding means. The connection means may also include flat flanges. A connection using flat flanges, advantageously equipped with an O-ring (preferably of known plastic composition, in order to correct any subsequent analysis aimed at quantifying and / or characterizing the plastic particles present in the sample), ensures the connection is watertight.

[0092] Advantageously, the device may include a cap or lid for closing the first opening of the upper chamber. This may be a screw-on or snap-on cap or lid. This cap or lid may enable step e) of the process according to the invention to be carried out, which comprises agitating the assembly formed by the first, second, and third interconnected chambers without loss. Advantageously, the cap or lid may be made of stainless steel, so as to avoid the generation of extractable compounds that could interfere with any subsequent analysis aimed at quantifying and / or characterizing the plastic particles present in the sample.

[0093] According to one embodiment of the invention, the device may further comprise at least one filter intended to be disposed at the outlet of the intermediate chamber once the step of disconnecting the intermediate chamber from the lower chamber has been carried out (step g) of the process according to the invention). This filter may be configured to at least retain the plastic particles and the unconsolidated solid matrix in the intermediate chamber, and advantageously to allow the evacuation of any liquid trapped in the intermediate chamber. It may be a sieve, a membrane filter, or a mineral filter. In a design in which the filter is a sieve, the mesh size of the sieve, preferably made of stainless steel, is between 1 µm and 5 mm, preferably between 1 and 300 µm.According to a design in which the filter corresponds to a mineral filter, this filter can be composed of micronized pure silica particles, ranging in size from 1 to 300 µm. Such a filter can be advantageous if the unconsolidated solid matrix of the initial sample has a coarse particle size, which would not allow the plastic particles to be preserved in the intermediate chamber. Indeed, if the initial sample... With an average particle size of approximately 5 mm, all small plastic particles, ranging from tens to hundreds of microns, will pass through the inter-grain space and thus fall through the final sample. Advantageously, this filter can be connected to the second opening of the intermediate chamber using the connection means of the device according to the invention.

[0094] As already mentioned above, according to a highly preferred embodiment, the device may include a fourth chamber or collection chamber, with a volume at least equal to the volume of the intermediate chamber. This fourth chamber includes a first opening that can be connected to the second opening of the intermediate chamber by means of the connection means of the device according to the invention, and a second opening comprising a filter configured to retain the plastic particles and the unconsolidated solid matrix in the fourth chamber. Advantageously, such a connection of the intermediate chamber with the collection chamber can be made at the end of step g) of the process according to the invention, after opening the second opening of the intermediate chamber by means of the controllable opening and closing means of the second opening of the intermediate chamber.Such a collection chamber can be used to obtain a superconcentrated sample. The filter can advantageously be configured to allow at least one drainage of any liquid trapped in the intermediate chamber. It can be a sieve, a membrane filter, or a mineral filter. In a sieve design, the mesh size, preferably stainless steel, is between 1 µm and 5 mm, preferably between 1 and 300 µm. In a mineral filter design, the filter can be composed of micronized pure silica particles, with a size between 1 and 300 µm. Advantageously, when the fourth chamber is cylindrical, the second opening, fitted with a filter, can be located on the lower wall of this collection chamber to facilitate liquid drainage.Advantageously, the collection chamber may include a cap or lid to close its initial opening. This may be a screw-on or snap-on cap or lid. Once disconnected from the intermediate chamber, the collection chamber can be used to transport and store the superconcentrated sample without loss or risk of contamination. Advantageously, the cap or lid may be made of stainless steel to prevent the generation of extractable compounds that could interfere with any subsequent analysis aimed at quantifying and / or characterizing the plastic particles present in the sample.

[0095] Furthermore, the invention relates to a method for superconcentrating a sample comprising plastic particles and / or organic matter in a matrix unconsolidated solid at a predefined overconcentration rate. In other words, the invention relates to a process for producing, from a first sample comprising plastic particles and / or organic matter in an unconsolidated solid matrix, a second sample having a concentration of plastic particles and / or organic matter multiplied by a predefined overconcentration rate relative to the concentration of plastic particles and / or organic matter of the first sample.

[0096] The method according to the invention can be implemented by means of any of the embodiments of the device according to the invention described above. The method according to the invention comprises at least steps a) to g) described above.

[0097] According to one embodiment of the invention, in step c), the sample to be overconcentrated can be introduced into the assembly formed by the upper chamber, the intermediate chamber, and the lower chamber connected together such that the volume of the introduced sample occupies at least a portion (for example, 10%) of the volume of the upper chamber. This ensures that, at the end of step d), the total volume of sample present in the device according to the invention is equal to the sum of the volumes of the lower and intermediate chambers, and thus the accuracy of the overconcentration obtained at the end of step g). This accuracy is important for subsequent analyses involving the quantification and / or characterization of plastic particles. Furthermore, in this manner, it is not necessary to accurately measure the volume of the sample to be introduced beforehand, which simplifies the implementation of the method according to the invention.

[0098] According to one embodiment of the invention, during step d), excess sample from the upper chamber can be removed by rinsing, for example, with purified or distilled water. It should be noted that even if the sample has been introduced so as to reach exactly the first opening of the intermediate chamber, particles constituting the sample may adhere to the walls of the upper chamber. Removing any excess ensures that, at the end of step d), the total volume of sample present in the device according to the invention is equal to the sum of the volumes of the lower and intermediate chambers, and thus the accuracy of the overconcentration obtained at the end of step g). This accuracy is important for subsequent analyses involving the quantification and / or characterization of plastic particles and / or organic matter.

[0099] According to one embodiment of the invention, in step e), the first, second, and third interconnected chambers can be agitated by means of a vibrating table, a rotary or translational shaker, an ultrasonic device, or differential or equilibrium centrifugation. Alternatively, the first, second, and third interconnected chambers can be agitated manually. Agitation using a vibrating table may be preferred when the volume of the upper chamber is limited, for example, between 0.2 and 0.5 times the volume of the intermediate chamber. In this case, the free volume in the upper chamber is limited, and the use of a vibrating table does not require a free volume for agitation. According to one embodiment of the invention, the predefined duration of step e) may be at least 1 minute, and preferably 5 minutes.

[0100] Preferably, at least during step f) of the process according to the invention, the upper, intermediate, and lower chambers are arranged such that a plane passing through their interconnected openings (i.e., the second opening of the upper chamber and the first opening of the intermediate chamber, and the second opening of the intermediate chamber and the first opening of the lower chamber) is substantially horizontal, as this maximizes gravity flow. According to one embodiment of the invention, the predefined duration of step f) can be at least 15 minutes, and is preferably 30 minutes. Such durations allow for granular segregation of the plastic particles.

[0101] According to an embodiment in which the process according to the invention is implemented by means of a device comprising a filter as described above, the following step h) can be added after step g) of the process according to the invention:

[0102] (h) The second opening of the second chamber is connected to the filter, the second opening of the second chamber is opened by means of the controllable opening and closing means of the second opening of the second chamber, the second chamber and the filter are connected to each other so as to allow gravity flow of any fluid contained in the second chamber, and the second chamber is disconnected from the filter by disconnecting the second opening of the second chamber and the filter by means of the connecting means. This step allows the evacuation of any liquid trapped in the intermediate chamber, while retaining the plastic particles and the unconsolidated solid matrix in the intermediate chamber.

[0103] According to the highly preferred embodiment in which the device comprises a fourth chamber, the following step h') can be added after step g) of the method according to the invention:

[0104] h') said second chamber is connected to said fourth chamber by connecting The first opening of the fourth chamber to the second opening of the second chamber by means of the connection means, the said second opening of the said second chamber is opened by means of the controllable opening and closing means of the said second opening of the said second chamber, the said second and fourth chambers are arranged connected to each other in such a way as to allow A gravity flow of the sample from the second chamber to the fourth chamber is established, and the second chamber is disconnected from the fourth chamber by disconnecting the first opening of the fourth chamber and the second opening of the second chamber using the connecting means. The fourth chamber includes a suitable filter, and the liquid contained in the second chamber is then drained. The final, highly concentrated sample remains in the collection chamber. Advantageously, the walls of at least the second chamber can be rinsed before its disconnection from the fourth chamber to ensure complete transfer of particles to the fourth chamber. The fourth chamber, also called the collection chamber, can be used to condition the final sample. Advantageously, the first opening of the fourth chamber can be closed with a stopper, for example, a screw-on or snap-on one.Once disconnected from the intermediate chamber, the collection chamber can be used to transport and store the super-concentrated sample, without loss and without risk of contamination.

[0105] Advantageously, the steps of the process according to the invention can be repeated, the final sample obtained at the end of one repetition of the steps of the process according to the invention becoming the initial sample of the next repetition, the degree of overconcentration being able to change or remain the same from one repetition to another, and at least the volume of the second chamber and / or the third chamber being modified according to the degree of overconcentration of the repetition in progress. Indeed, the volume of the lower chamber and / or the intermediate chamber can be adapted from one repetition to the next, depending on the expected degree of overconcentration.

[0106] Figure 1 illustrates, schematically and without limitation, an example of an implementation of the device according to the invention. In this design, the device comprises a first chamber 10, a second chamber 20, and a third chamber 30, all three cylindrical in shape and connected to each other via connecting means 15, 16, 25, 26, 25', 26', 35, 36. The configuration of the device according to the invention shown in this figure can be obtained by implementing step b) of the method according to the invention and can be used for implementing steps c) to f) of the method according to the invention. The first chamber 10 comprises a first opening 11 and a second opening 12, the second chamber comprises a first opening 21 and a second opening 22, and the third chamber comprises an opening 31.The opening 12 of the first chamber is in communication (schematized by the dotted line) with the opening 21 of the second chamber 20 and the opening 31 of the third chamber is in communication (schematized by the dotted line) with the opening 22 of the second chamber 20 thanks to the controllable opening and closing means 23, 24 of the first 21. and second 22 openings of the second chamber 20 in the form of a guillotine valve, which are, for this figure, actuated in the open position (note that [Fig.1] would be identical in the case of a device comprising controllable opening and closing means of the second opening of the first chamber instead of controllable opening and closing means of the first opening of the second chamber). For this design, the openings 11, 12, 21, 22, 31 of the three chambers 10, 20, 30 occupy the entire surface of the flat faces of the three chambers 10, 20, 30. The absence of a rim allows for easier introduction of the sample into the device according to the invention during step c) of the process according to the invention, better agitation during step e) of the process according to the invention, as well as better granular segregation during step f) of the process according to the invention.For this design, the connection means comprise flat flanges 15, 25, 25', 35 supported by pilot-operated opening and closing means 23, 24 of the second chamber 20. The sealing of the assembly is ensured by O-rings 26, 26' disposed in grooves machined into the flat flanges 15, 25, 25', 35, which are crushed when the flat flanges 15, 25, 25', 35 are tightened with the guillotine valves 23, 24 of the intermediate chamber 20. According to step c) of the method according to the invention, a sample can be introduced into the device configuration of [Fig. 1] via the opening 11 of the first chamber 10. According to the invention, the ratio between the volume V3 of said third chamber 30 and the volume V2 of the second chamber is equal to (S1), where S is the desired overconcentration rate. According to the design of the figure, the volume VI of the first chamber 10 is greater than at least 20% of the volume V2 of the second chamber 20.This allows for a free volume within the assembly formed by the first, second, and third chambers connected together, after step c) of the process according to the invention described below. This free volume is advantageous for allowing agitation of the introduced sample and / or for allowing the introduction of a liquid that promotes agitation and sedimentation of the particles constituting the initial sample. At the end of step e), which consists of agitating the three chambers 10, 20, 30 thus connected together, and step f), which consists of letting the three chambers 10, 20, 30 connected together and arranged so as to allow gravity flow to rest (here the three chambers will advantageously be arranged as shown in [Fig.l], that is to say such that a plane passing through their interconnected openings is horizontal), a granular segregation operation by density will take place within the sample and the plastic and / or organic matter particles (less dense than the constituents of the unconsolidated solid matrix) will tend to be found in the upper part of the sample, or even on its surface if the agitation time and the rest time are sufficiently long. In other words, the particles. plastic and / or organic matter are found, at the end of step f) at least in the second chamber 20, but also in the first chamber 10, due to the liquid which was introduced during step e).

[0107] Figure 2 illustrates a particular configuration of the implementation example of the device in Figure 1 (thus, the common elements will not be described again), which can, for example, be implemented during step g) of the process according to the invention. Thus, compared to Figure 1, the controllable opening and closing means of the second opening 22 of the second chamber 20 are here actuated in the closed position. The assembly formed by the upper chamber 10 and the intermediate chamber 20 can then be disconnected from the lower chamber 30, by means of the connecting means 25', 26', 35, 36 in order to isolate the super-concentrated sample present in at least the intermediate chamber 20, but also in the upper chamber 10, since a liquid was introduced during step e).

[0108] Figure 3 illustrates an example of an implementation of the device of Figure 1 (thus, the common elements will not be described again), the assembly formed by the upper and intermediate chambers 10, 20 being disconnected from the lower chamber 30, the device according to this design further comprising a filter 40 connected to the second chamber 20 by means of the connection means 25', 26', 45, 46. In this case, for this design, the filter 40 also comprises a flat flange 45 having a groove in which an O-ring 46 is disposed. The connection of the filter 40 to the second chamber 20 is made by tightening the flat flanges 25', 45 onto the guillotine valve 24 of the second chamber 20.Such a configuration of the device according to the invention can advantageously be implemented during step h) of the process according to the invention, during which a liquid phase can be evacuated from the contents of the second chamber 20 obtained at the end of step g) of the process according to the invention. This can be a liquid contained in the initial sample itself, or the liquid introduced during step e) of the process according to the invention, to facilitate the agitation of the sample and / or granular segregation.

[0109] Figure 4 illustrates an example of an implementation of the device of Figure 1 (thus, the common elements will not be described again), the assembly formed by the upper and intermediate chambers 10, 20 being disconnected from the lower chamber 30, the device according to this design further comprising a fourth chamber 50 connected to the second chamber 20 by means of the connecting means 25', 26, 55, 56. In this case, for this design, the fourth chamber 50 also includes a flat flange 55 having a groove in which an O-ring 56 is disposed. The connection of the first opening 51 of the fourth chamber 50 to the second chamber 20 is made by tightening the flat flanges 25', 55 onto the guillotine valve 24 of the second chamber 20. Such a configuration of the device according to the invention This can advantageously be implemented during step h') of the process according to the invention, during which the contents of the second chamber 20, as determined by step g) of the process according to the invention, are transferred into the fourth chamber 50, which can then serve as a collection chamber. The fourth chamber 50 includes a filter 52 at an opening (not shown) at its base, allowing any liquid contained in the intermediate chamber 20 to drain away. This results in conditioning of the final sample. Advantageously, the fourth chamber 50 has a plug (not shown) which can be used to close the opening 51 of the fourth chamber 50, once disconnected from the second chamber 20 by means of the connection means 25', 26', 55, 56. Advantageously, the fourth chamber 50 has a second plug (not shown) which can be used to close the opening at the level of the filter 52 of the fourth chamber 50.

[0110] The invention further relates to a use of the process as described above for overconcentrating a sample comprising plastic particles and / or organic matter in an unconsolidated solid matrix according to a predefined overconcentration rate, the process being implemented by means of any variant of the device described above.

[0111] Thus, the invention relates to a device and a method for concentrating plastic and / or organic matter particles in a controlled manner within a sample, in particular to meet the detection thresholds of analytical methods conventionally used to detect and / or characterize mesoplastics and microplastics and / or organic matter. Furthermore, the device according to the invention is portable and easy to use. Moreover, the present invention, in its preferred embodiment, allows for the preparation and packaging of samples to be analyzed with fewer steps compared to the prior art, thereby avoiding contamination and losses (for example, those related to the adhesion of particles to the walls of laboratory glassware or to the filters used) that could distort the analysis of plastic particles. Examples

[0112] The characteristics and advantages of the device and method according to the invention will become clearer upon reading the following application example, which aims to super-concentrate plastic particles in an unconsolidated sample.

[0113] A volume of IL of sediments including plastic particles was collected from a beach using a steel trowel and was placed in a steel funnel whose basal opening was in the closed position via a guillotine valve.

[0114] The funnel was placed above the upper chamber (of volume 1 L) which had been previously connected to the intermediate chamber (of volume 0.1 L), itself- It was also connected to the lower chamber (with a volume of 0.9 L). The guillotine valves separating the upper chamber from the upper and lower chambers were actuated to the open position. The funnel's basal opening was then opened to transfer the entire sample volume into the device.

[0115] The guillotine valve of the first opening of the intermediate chamber was then actuated to the closed position and the upper chamber was rinsed with distilled water. The guillotine valve of the first opening of the intermediate chamber was then actuated to the open position, and a volume of 0.5 L of distilled water was introduced through the first opening of the upper chamber.

[0116] The first opening of the upper chamber is then closed with a stopper to allow manual agitation of the sample in the device for 1 min. The device was then left in a vertical position for 30 min to allow the grains constituting the sample to settle. The coarsest grains (0.5–4 mm in diameter), composed of quartz, quickly settle to the bottom of the device. Some of the finer grains, and any plastics present, may remain suspended in the water, which retains some turbidity.

[0117] The guillotine valve of the second opening of the intermediate chamber is then actuated to the closed position, and the assembly formed by the upper chamber and the intermediate chamber is disconnected from the lower chamber.

[0118] The collection chamber, the lower opening of which has been previously fitted with a steel filter with a 70 µm mesh, is then connected below the guillotine valve of the opening. Opening the guillotine valve allows the transfer of the 0.1 L of sample through which the 0.5 L of distilled water percolates before being filtered through the 70 µm filter. Additional agitation is implemented to accelerate the filtration of all the water. Once all the hydrogen peroxide has been filtered, hydrogen peroxide is used to rinse the walls of the upper chamber and ensure the complete transfer of all particles present to the collection chamber. The collection chamber can then be disconnected. For example, a photograph of the surface of the superconcentrated sample can be taken. The collection chamber is then closed at its upper and lower ends using the stoppers.

[0119] The sample can then be studied in the laboratory for further analyses, such as analyses aimed at quantifying and / or characterizing the plastic particles present in the sample. If the detection threshold is not reached, a further overconcentration step can be carried out.

Claims

Demands

1. Device for superconcentrating a sample comprising plastic particles and / or organic matter in an unconsolidated solid matrix, characterized in that said device comprises: - a first chamber (10) comprising a first (11) and a second (12) openings; - a second chamber (20) comprising a first (21) and a second (22) openings; - a third chamber (30) comprising at least a first opening (31); - controllable opening and closing means (23) of said first opening (21) of said second chamber (20) or of said second opening (12) of said first chamber (10), as well as controllable opening and closing means (24) of said second opening (22) of said second chamber (20);- connection means (15, 16, 26, 25, 25', 26', 35, 36) configured to allow at least the connection and disconnection of said second opening (12) of said first chamber (10) with said first opening (21) of said second chamber (20), and the connection and disconnection of said first opening (31) of said third chamber (30) with said second opening (22) of said second chamber (20); and in that a ratio between, on the one hand, the sum of the volume (V2) of said second chamber (20) and the volume (V3) of said third chamber (30), and on the other hand, the volume (V2) of said second chamber (20) is equal to a predefined overconcentration rate.;

2. Device according to claim 1, wherein said controllable opening and closing means (23) of said first opening (21) of said second chamber (20) or of said second opening (12) of said first chamber (10), and / or said controllable opening and closing means (24) of said second opening (22) of said second chamber (20) correspond to a guillotine valve, a shovel valve, a knife valve, a ball valve, a wheel valve, or a butterfly valve.

3. A device according to any one of the preceding claims, wherein said device comprises means for closing said first opening (11) of said first chamber (10), for example in the form of a lid.

4. Device according to any one of the preceding claims, said device further comprises a filter (40), said filter (40) being able to be connected to said second opening (22) of said second chamber (20) by means of said connection means (25', 26', 46, 47), said filter (40) being configured to retain said plastic particles and / or organic matter and said unconsolidated solid matrix in said second chamber (20).

5. Device according to any one of claims 1 to 3, wherein said device further comprises a fourth chamber (50), of a volume at least equal to said volume of said second chamber (20), said fourth chamber (50) having a first opening (51) which can be connected to said second opening (22) of said second chamber (20) by means of said connection means (25', 26', 56, 57), and a second opening having a filter (52) configured to retain said plastic particles and / or organic matter and said unconsolidated solid matrix in said fourth chamber (50).

6. A method for superconcentrating a sample comprising plastic particles and / or organic matter in an unconsolidated solid matrix to a predefined superconcentration rate, said method being implemented using the device according to any one of the preceding claims, characterized in that at least the following steps are performed: a) Said first chamber (10) and said second chamber (20) are connected to each other by connecting said second opening (12) of the first chamber (10) with said first opening (21) of said second chamber (20) by means of said connecting means (15, 16, 26, 25), and said first opening (21) of said second chamber (20) is opened by means of the controllable opening and closing means (23) of said first opening (21) of said second chamber (20), or alternatively,a) The second opening (12) of the first chamber (10) is opened by means of the controllable opening and closing means (23) of the second opening (12) of the first chamber (10); b) The second chamber (20) and the third chamber (30) are connected to each other by connecting the second opening, (22) of said second chamber (20) with said first opening (31) of said third chamber (30) by means of the connection means (25', 26', 35, 36), and said second opening (22) of said second chamber (20) is opened by means of said controllable opening and closing means (24) of said second opening (22) of said second chamber (20); (c) The said sample is introduced into the said first (10), second (20) and third (30) chambers connected to each other by the said first opening (11) of the said first chamber (10) and in such a way as to reach at least the said first opening (21) of the said second chamber (20); d) The said first opening (21) of the said second chamber (20) is closed by means of the said controllable opening and closing means (23) of the said first opening (21) of the said second chamber (20) or, alternatively, the said second opening (12) of the said first chamber (10) is closed by means of the said controllable opening and closing means (23) of the said second opening (12) of the said first chamber (10), the excess of the said sample present in the said first chamber (10), and the said first opening (21) of the said second chamber (20) is reopened by means of the said controllable opening and closing means (23) of the said first opening (21) of the said second chamber (20), or alternatively, the said second opening (12) of the said first chamber (10) is reopened by means of the said controllable opening and closing means (23) of the said second opening (12) of the said first chamber (10); e) A liquid is introduced at the level of said first opening of said first chamber into said first (10), second (20) and third (30) chambers connected with each other and said first (10), second (20) and third (30) chambers connected with each other are agitated for a first predefined period, for example by means of a vibrating table, a rotary or translational agitator, an ultrasonic device, or differential or equilibrium centrifugation; f) The said first (10), second (20) and third (30) interconnected chambers are left to rest for a second predefined period, the said first (10), second (20) and third (30) interconnected chambers being arranged so as to permit a gravity flow of at least a part of said sample from said first chamber (10) to said third chamber (30) via said second chamber (20); g) Said second opening (22) of said second chamber (20) is closed by means of said pilotable opening and closing means (24) of said second opening (22) of said second chamber (20), (at least said third chamber (30) is disconnected from said second chamber (20) by means of said connection means), and said super-concentrated sample is obtained in at least said second chamber (20).

7. A method according to claim 6, wherein prior to step e), a liquid is introduced, through said first opening (11) of said first chamber (10), into said first, second and third chambers (10, 20, 30) connected to each other.

8. A method according to any one of claims 6 to 7, wherein said method is implemented by means of the device according to claim 4, and wherein said method further comprises a step h) in which: said second opening (22) of said second chamber (20) is connected to said filter (40), said second opening (22) of said second chamber (20) is opened by means of said controllable opening and closing means (25', 26', 45, 46) of said second opening (22) of said second chamber (20), said second chamber (20) and said filter (40) are arranged connected to each other so as to permit gravity flow of any fluid contained in said second chamber (20), and said second chamber (20) is disconnected from said filter (40) by disconnecting said second opening (22) of said second chamber (10) and said filter (40) by means of said connection means (25', 26', 45, 46).

9. A method according to any one of claims 6 to 7, wherein said method is implemented by means of the device according to claim 5, and wherein said method further comprises a step h') in which: said second chamber (20) is connected to said fourth chamber (50) by connecting said first opening (51) of said fourth chamber (50) to said second opening (22) of said second chamber (20) by means of said connecting means (15, 16, 55, 56), and an opening is opened said second opening (22) of said second chamber (20) by means of said controllable opening and closing means (24) of said second opening (22) of said second chamber (10), said second (20) and fourth (50) chambers are arranged connected together so as to permit a gravity flow of said super-concentrated sample present in said second chamber (20) to said fourth chamber (50), and said second chamber (20) is disconnected from said fourth chamber (50) by disconnecting said first opening (51) from said fourth chamber (50) and said second opening (22) from said second chamber (12) by means of said connection means (25',26', 55, 56).

10. Use of the process according to any one of claims 6 to 9 for overconcentrating a sample comprising plastic particles and / or organic matter in an unconsolidated solid matrix to a predefined overconcentration rate, said process being implemented by means of the device according to any one of claims 1 to 5.

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