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 particles of plastic and / or organic matter 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 sludge, in a marine, river or lake environment, or even in the ambient air.

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

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

[0004] The use of plastics (polymer-based materials) has been growing in global industry for many years. 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 source of pollution.

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

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

[0007] According to some classifications, microplastics are particles of any type of polymer and of sizes less than 5 mm and greater than 1 pm, with mesoplastics having 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 flows or even by the wind, and are found in all types of environments, including ambient air, soils, waterways, sediments and also at sea.

[0008] Today the characterization of the marine, fluvial or lacustrine 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 enable 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 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. Among these analytical methods, we can cite thermal extraction-desorption analyses coupled with gas chromatography and mass spectrometry, pyrolysis coupled with gas chromatography, Fourier transform infrared spectroscopy, mass spectrometry or Raman spectroscopy.

[0010] For example, patent application FR 21 / 05123 A1 (filing number), which relates to a method for characterizing the presence and / or quantifying at least one polymer in a porous medium, 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, requires concentrations greater than 0.2% by weight of the sample analyzed 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, and in particular when these are very low.

[0011] In the field of petroleum geosciences or environmental sciences, the methods conventionally 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, mention may be made, for example, of patents EP0691540A1, US10088465A1, and WO2022 / 200091A1, which relate to methods for characterizing organic matter from a reservoir rock, a source rock or a 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 requires preparing samples whose concentration is lower than 0.1% by weight by acid attacks to eliminate the mineral matrix and thus relatively increase the proportion of organic matter. Prior art

[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 / 10.1016 / j.chemosphere.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 are known which relate to devices and / or methods for separating microplastics from a sample, such as patent application EP3272421 A1, and 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 sediment / microplastic separation carried out using solutions with a density higher than that of the microplastics (such as, for example, 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. There is therefore a lot of handling between sampling from the environment, conditioning and preparing the sample for analysis. In addition, the quantities of materials (sand, sediment, soil...) which are collected and processed must often be substantial (1 kilogram or more) so that the final treated sample is in contents (concentrations) compatible with the detection thresholds of the methods conventionally used to identify and characterize microplastics. In any case, the devices according to the prior art do not make it possible to guarantee a predefined concentration of the sample ultimately obtained.

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

[0020] The present invention makes it possible to overcome these drawbacks. In particular, the invention relates to a device and a method making it possible to concentrate the particles of plastic and / or organic matter in a controlled manner, in particular in order to adjust to the detection thresholds of analytical methods aimed at detecting and / or characterizing mesoplastics and microplastics and / or organic matter. In addition, the device according to the invention is portable and easy to use. Furthermore, the present invention can allow, in its preferred variant, the preparation and conditioning of samples to be analyzed with a reduced number of manipulations compared to the prior art, which makes it possible to avoid contamination and losses (for example, linked to the adhesion of particles to the walls of laboratory glassware, or to the filters used) which could distort the analysis of plastic particles. Summary of the invention

[0021] The invention relates to a device for overconcentrating a sample comprising plastic and / or organic matter particles 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 said second opening of said first chamber, as well as 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 connecting said second opening of said first chamber with said first opening of said second chamber, and connecting and disconnecting 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 implementation 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 gate valve, a knife valve, a ball valve, a handwheel valve, or a butterfly valve.

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

[0031] According to a first variant implementation of the invention, said device may further comprise 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 particles of plastic and / or organic matter as well as said unconsolidated solid matrix in said second chamber.

[0032] According to a second variant implementation of the invention, said device may further comprise a fourth chamber, of 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 particles of plastic and / or organic matter as well as said unconsolidated solid matrix in said fourth chamber.

[0033] The invention further relates to a method for overconcentrating a sample comprising plastic and / or organic matter particles in an unconsolidated solid matrix according to a predefined overconcentration rate, said method being carried out 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 to each other by connecting said second opening of the first chamber with said first opening of said second chamber by means of said 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;

[0036] b) said second chamber and said third chamber are connected to each other 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 so as to reach at least said first opening of said second chamber;

[0038] d) Said first opening of said second chamber is closed by means of said controllable opening and closing means of said first opening of said second chamber or, alternatively, said second opening of said first chamber is closed by means of said controllable opening and closing means of said second opening of said first chamber, the excess of said sample present in said first chamber is removed, and said first opening of said second chamber is reopened by means of said controllable opening and closing means of said first opening of said second chamber, or alternatively, said second opening of said first chamber is reopened by means of said controllable opening and closing means of said second opening of 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 duration, for example by means of a vibrating table, a rotary or translational agitator, an ultrasonic device, or even differential or equilibrium centrifugation;

[0040] f) Said first, second and third interconnected chambers are left to stand for a second predefined period, said first, second and third interconnected chambers being arranged so as to allow a gravitational flow of at least a portion of said sample from said first chamber to said third chamber via said second chamber;

[0041] g) Said second opening of said second chamber is closed by means of said controllable opening and closing means of said second opening of said second chamber, (at least said third chamber is disconnected from said second chamber by means of said connection means), and said superconcentrated sample is obtained in at least said second chamber.

[0042] According to an implementation of the invention, prior to step e), it is possible to introduce, through said first opening of said first chamber, a liquid into said first, second and third chambers connected to each other.

[0043] According to an implementation of the invention, said method can be implemented by means of the device according to the first variant described above, and said method can 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, said second chamber and said filter are arranged connected to each other so as to allow a gravitational flow of any fluid contained in said second chamber, and said second chamber is disconnected from said filter by disconnecting said second opening said second chamber and said filter by means of said connection means.

[0044] According to an implementation of the invention, said method can be implemented by means of the device according to the second variant described above, and said method can 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 connection 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 overconcentrated sample present in said second chamber towards said fourth chamber,and disconnecting said second chamber from said fourth chamber by disconnecting said first opening from said fourth chamber and said second opening from said second chamber by means of said connecting means.

[0045] The invention further relates to a use of the method as described above for overconcentrating a sample comprising particles of plastic 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. List of figures [Fig 1]

[0046] [Fig.l] 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.l], which can be implemented during step g) of the method according to the invention. [Fig 3]

[0048] [Fig.3] illustrates an alternative implementation of the device of [Fig.l], additionally comprising a filter. [Fig 4]

[0049] [Fig.4] illustrates another embodiment of the device of [Fig.1], additionally comprising a fourth chamber. Description of the embodiments

[0050] The invention relates to a device and a method for superconcentrating a sample comprising plastic and / or organic matter particles in an unconsolidated solid matrix according to a predefined superconcentration rate. By solid matrix unconsolidated means a solid phase formed of grains or fibers not welded together.

[0051] In other words, the invention aims to obtain a new sample (hereinafter called final sample or superconcentrated sample) comprising particles of plastic and / or organic matter in a concentration greater than the concentration of the input sample (hereinafter called initial sample) of the device and / or method according to the invention, and according to a predefined superconcentration rate. By superconcentration rate, we mean a value of the ratio between the concentration of the final sample and the concentration of the initial sample in particles of plastic and / or organic matter. For the implementation of the invention, there is no need to know the concentrations of the initial and final samples. It is sufficient to predefine the ratio of these concentrations.For example, if an overconcentration rate of 10 is predefined, this means that the aim is to determine, by means of 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 comprise plastic particles in an unconsolidated solid matrix, may result from sampling in an aquatic (marine, lake, river), terrestrial (soils, sediments, beach, sewage treatment plant sludge) or atmospheric (ambient air, atmospheric deposits) 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 the sedimentary particles suspended in the water. When the sample results from sampling in the ambient air, the unconsolidated solid matrix may correspond to the particles suspended in the air (for example metal particles, soot, dust, etc.), other than plastic particles. In an implementation where samples are taken from aquatic or atmospheric environments, the samples may be pre-filtered (e.g. with a sieve, membrane filter, etc.) so that water and / or air present in the sample are essentially removed.

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

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

[0055] Subsequently, the device and the method according to the invention will be described for an 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 of unconsolidated solid matrices, whatever 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 said second opening of said first chamber, as well as 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 connecting said second opening of the first chamber with at least said first opening of said second chamber, as well as connecting and disconnecting 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 with the first chamber and / or with the third chamber. Subsequently, for the purpose of simplifying 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 with reference to the configuration (hereinafter called the service position) of the device according to the invention according to which the second chamber is connected to both the first chamber and the third chamber and are arranged so as to allow a gravity flow from the first chamber to the second chamber and then to the third chamber.In other words, in the service position, the first chamber is "above" the second chamber, which is itself "above" the third chamber. By connected chambers, we mean chambers with an opening in one connected to an opening in the other; thus the interior volumes of the chambers are fluidly connected to each other, to allow exchanges of their contents from one chamber to the other.

[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] 1^=5

[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 according to an overconcentration rate of 10 (S=10) (in other words, if one wishes to multiply by 10 the concentration of the plastic particles 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 in other words, 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 10cL, the volume of the third chamber of the device has a volume of 90cL, and vice versa.

[0067] According to one implementation 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] VI to O.2*V2

[0069] where V1 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 in the assembly formed by the first chamber, the second chamber and the third chamber connected to each other, after step c) of the method according to the invention described below. This free volume allows stirring of the introduced sample, which is more after introducing a liquid promoting stirring and sedimentation of the particles constituting the initial sample, as will be explained below. Preferably, to further facilitate stirring and / or to allow the introduction of a quantity of liquid, the volume of the upper chamber may be at least twice the volume of the second chamber. Alternatively, the volume of the upper chamber may be equal to the volume of the lower chamber. This allows simplified manufacture 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 to each other by connecting said second opening of the first chamber with said first opening of said second chamber by means of the connection means, and opens said first opening of said second chamber 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 to each other 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 so as to reach at least said first opening of said second chamber;

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

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

[0076] f) Said first, second and third interconnected chambers are left to stand for a second predefined period, said first, second and third interconnected chambers being arranged so as to allow a gravitational flow of at least a portion of said sample from said first chamber to said third chamber via said second chamber;

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

[0078] The method may be implemented using the device according to any one of the variants or any one of the combinations of variants described above.

[0079] Thus, the device and the method according to the invention are based on the fact that the particles of the unconsolidated solid matrix will follow a granular segregation resulting from the differential decantation of the particles (or even a sedimentation speed) of the initial sample, the plastic particles having a tendency to remain either in suspension in the introduced liquid, or close to the surface of the solid matrix after stirring and resting in a (substantially) vertical position because they have a density substantially lower than that of the natural mineral particles. Furthermore, the volumes of the lower and intermediate chambers are configured to allow 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 made possible by means of, on the one hand, the controllable opening and closing means of the second opening of the intermediate chamber, which make it possible to close the intermediate chamber without manipulating the chamber itself (which would risk disrupting the particle size sorting carried out), and on the other hand, by means of the connection means between the lower and intermediate chambers. This produces a final sample with the desired overconcentration in the intermediate chamber. In addition, the controllable opening and closing means of the first opening of the intermediate chamber (or of the second opening of the upper chamber, in an equivalent manner) allow the introduction into the device of any volume of the sample to be overconcentrated (as long as it is at least equal to the sum of the volumes of the lower chamber and the intermediate chamber).Indeed, by these controllable opening and closing means of the first opening of the intermediate chamber (or of the second opening of the upper chamber, in an equivalent manner), it is easy to remove the excess sample which could be present in the upper chamber (for example by rinsing). The protocol is thus facilitated because there is no precise and exact measurement of the sample to be made prior to its introduction into the device. Furthermore, this makes it possible to ensure a controlled overconcentration rate in the end, because the volume of sample at the inlet of the process according to the invention is guaranteed.

[0080] According to a very preferred variant of the invention, the advantages of which will be described in more detail below, the device may further comprise a fourth chamber (hereinafter called the collection chamber), of volume at least equal to the volume of the intermediate chamber, this fourth chamber comprising a first opening which 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 can be configured to remove any fluid present in the initial sample or added during the method according to the invention. In particular, this filter can allow rinsing of the intermediate chamber (for example with purified water), to allow total transfer of the overconcentrated sample from the intermediate chamber directly to the collection chamber.By limiting handling and allowing total transfer of the over-concentrated sample, this variant limits the risks of contamination and losses (for example, linked to the adhesion of particles to the walls of laboratory glassware, or to the filters used) which could distort the analysis of plastic particles. Furthermore, the intermediate chamber can then be used to carry out other over-concentrations and / or for other samples.

[0081] The upper, intermediate and lower chambers (where applicable, the collection chamber) of the device according to the invention may be of any shape, including shapes that differ from each other, provided that the intermediate chamber can be connected to the upper chamber and to the lower chamber (where applicable, to 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 (where applicable, and / or the collection chamber) of the device according to the invention may be of cylindrical or parallelepipedal shape.

[0082] Preferably, the upper chamber and / or the intermediate chamber and / or the lower chamber (where appropriate, the collection chamber) may be cylindrical in shape, 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 implementation of the invention, the material of the upper chamber and / or the intermediate chamber and / or the lower chamber (where appropriate, the collection chamber), and of their connection means may be stainless steel, aluminum or glass. Such materials make it possible to limit the adhesion of the particles constituting the sample to be concentrated on the wall of the chamber(s), which 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. Such materials also have the advantage of not generating extractable compounds which 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 connection between them can be made of polymer materials of known composition to ensure the subtraction of this signal in the event of contamination in the sample during the implementation of the method according to the invention.

[0084] According to an implementation in which the intermediate chamber is cylindrical or parallelepipedal in shape, the first opening of the intermediate chamber may be arranged on the upper wall of the intermediate chamber and the second opening of the intermediate chamber may be arranged on the lower wall of the intermediate chamber. Preferably, the opening in the upper wall of the intermediate chamber may be arranged in a central portion of the upper wall (for example located in an area centered on the barycenter of the upper wall, and the radius of which corresponds to 30% of the smallest dimension of the upper wall). An opening arranged in a central portion of the upper wall of the intermediate chamber allows a more homogeneous distribution of the particles constituting the sample compared to an eccentric 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 allows for easy introduction of the sample into the upper chamber. Advantageously, the second opening of the intermediate chamber may be arranged on the lower wall of the intermediate chamber so that its barycenter is aligned with the first opening of the upper chamber along a vertical axis. This may facilitate the gravitational flow of the particles constituting the sample through the intermediate chamber. Preferably, the second opening of the intermediate chamber substantially occupies the surface of the lower wall of the intermediate chamber. This makes it possible to avoid an accumulation of the particles constituting the sample to be concentrated in the bottom of the intermediate chamber.

[0085] Advantageously, the first opening of the lower chamber (respectively (the upper chamber, and where appropriate, the first opening of the collection chamber) being able to be connected to the second opening (located on the lower wall) of the intermediate chamber by means of the connection means, the shape and the dimension of the opening of the lower chamber (where appropriate, respectively the first opening of the collection chamber) can be in correspondence with that of the second opening (located on the lower wall) of the intermediate chamber. According to an implementation in which the intermediate chamber (where applicable, respectively the collection chamber) is cylindrical or parallelepipedal in shape, the opening of the lower chamber (where applicable, respectively the collection chamber) may be arranged on the upper wall of the lower chamber (where applicable, respectively the collection chamber). Preferably, the opening in the upper wall of the lower chamber (where applicable, respectively the collection chamber) may be arranged in a central part of the upper wall (e.g. located in an area centered on the barycenter of the upper wall, and the radius of which corresponds to 30% of the smallest dimension of the upper wall).An opening arranged in a central part of the upper wall of the lower chamber (where applicable, respectively the collection chamber) allows a more homogeneous distribution of the particles constituting the sample compared to an eccentric opening. Preferably, the first opening of the lower chamber occupies substantially the surface of the upper wall of the lower chamber (where applicable, respectively the collection chamber). Such a wide opening allows an easier passage of the sample from the intermediate chamber into the lower chamber (where applicable, respectively the collection chamber). Advantageously, the opening of the lower chamber (where applicable, respectively the collection chamber) can be arranged so that its barycenter is aligned with the first and second openings of the intermediate chamber along a vertical axis.This can facilitate the gravitational flow of the particles constituting the sample through the intermediate chamber towards the lower chamber (if applicable, respectively the collection chamber).

[0086] Advantageously, 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 connection means, the shape and the dimension of the second opening of the upper chamber can correspond to that of the first opening (located on the lower wall) of the intermediate chamber. According to an implementation according to which the intermediate chamber is of cylindrical or parallelepipedal shape, the second opening of the upper chamber can be arranged on the lower wall of the upper chamber. Preferably, the opening in the lower wall of the upper chamber can be arranged in a central part of the lower wall (for example located in an area centered on the barycenter of the lower wall, and whose radius corresponds to 30% of the smallest dimension of the lower wall).An opening provided in a central portion of the lower wall of the upper chamber allows for a more homogeneous distribution of the particles constituting the sample compared to an eccentric opening. Preferably, the second opening of the upper chamber occupies substantially the . surface of the lower wall of the upper chamber. Such a wide opening allows easy passage of the sample from the upper chamber into the intermediate chamber. Advantageously, the opening of the upper chamber can be arranged so that its barycenter 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 stirring of the constituents of the sample during step e) of the method according to the invention as well as facilitate the gravitational flow of the particles constituting the sample during step f) of the method according to the invention.

[0087] According to the invention, the first opening of the intermediate chamber or the second opening of the first chamber, in an equivalent manner, comprises controllable opening and closing means. The objective of these controllable opening and closing means is to allow in particular a closing of the intermediate chamber or of the upper chamber during step d) of the method according to the invention, in order to remove the excess sample which would 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 method according to the invention. Furthermore, this makes it possible to ensure a controlled overconcentration rate in the end, because the volume of sample at the inlet of the method 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 to allow in particular closing of the intermediate chamber after step g) of the method according to the invention, without manipulation which could cause the intermediate chamber to move and which could disturb the natural granulometric classification carried out by the particles of the unconsolidated solid matrix.

[0089] According to one implementation of the invention, the controllable opening and closing means of the intermediate chamber and / or the upper chamber may correspond to a guillotine valve, a gate 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 makes it possible to separate fluids or granular materials while ensuring a seal.

[0090] According to the invention, the device comprises 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 room.

[0091] According to one implementation of the invention, the connection means may consist of screwing means (threaded connection), snap-fastening means or sliding means. The connection means may also comprise flat flanges. A connection by means of flat flanges, advantageously provided with an O-ring (preferably of known composition in plastic material, in order to correct any subsequent analysis aimed at quantifying and / or characterizing the plastic particles present in the sample), makes it possible to ensure the tightness of the connection.

[0092] Advantageously, the device may comprise a cap or a cover for closing the first opening of the upper chamber. This may be a screw-on or snap-on cap or cover. This cap or cover may make it possible to carry out step e) of the method according to the invention, which comprises stirring the assembly formed by the first, second and third chambers connected to each other, without loss. Advantageously, the cap or cover may be made of stainless steel, so as to avoid the generation of extractable compounds which could interfere with any subsequent analysis aimed at quantifying and / or characterizing the plastic particles present in the sample.

[0093] According to one implementation of the invention, the device may further comprise at least one filter intended to be arranged 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 method 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 or a membrane filter or a mineral filter. According to a design in which the filter corresponds to a sieve, the meshes of the sieve, preferably made of stainless steel, have a dimension of 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, of a size between 1 and 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 has an average particle size of the order of 5 mm, all the small plastics, of the order of ten to one hundred microns, will then pass into the intergrain space and thus descend through the final sample. Advantageously, this filter can be connected to the second opening of the intermediate chamber, by means of the connection means of the device according to the invention.

[0094] As already mentioned above, according to a very preferred variant, the device can comprise a fourth chamber or collection chamber, of volume at least equal to the volume of the intermediate chamber, this fourth chamber comprising a first opening which 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. Such a connection of the intermediate chamber with the collection chamber can advantageously be made at the end of step g) of the method according to the invention, after having opened 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 make it possible to obtain conditioning of the overconcentrated sample.The filter may advantageously be configured to allow at least one evacuation of any liquid trapped in the intermediate chamber. It may be a sieve or a membrane filter or a mineral filter. According to a design in which the filter corresponds to a sieve, the meshes of the sieve, preferably made of stainless steel, have a dimension 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 may be composed of micronized pure silica particles, with a size between 1 and 300 μm. Advantageously, and when the fourth chamber is cylindrical in shape, the second opening provided with a filter may be arranged on the lower wall of this collection chamber, so as to facilitate the evacuation of liquid. Advantageously, the collection chamber may comprise a plug or a cover to close its first opening.This can 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 over-concentrated sample, without loss and without risk of contamination. Advantageously, the cap or lid can 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.

[0095] Furthermore, the invention relates to a method for overconcentrating a sample comprising particles of plastic and / or organic matter in an unconsolidated solid matrix according to a predefined overconcentration rate. In other words, the invention relates to a method for producing, from a first sample comprising particles of plastic and / or organic matter in an unconsolidated solid matrix, a second sample having a concentration of particles of plastic and / or organic matter multiplied by a predefined overconcentration rate relative to the concentration of particles of plastic and / or organic matter organic 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 an implementation of the invention, during 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 in such a way that the volume of the sample introduced occupies at least a part (for example 10%) of the volume of the upper chamber. This makes it possible to guarantee 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 precision of the overconcentration obtained at the end of step g). This precision is important for subsequent analyses in quantification and / or characterization of the plastic particles. In addition, in this way, it is not necessary to precisely 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 implementation of the invention, during step d), the excess sample present in the upper chamber can be removed by rinsing, for example with purified water 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 precision of the overconcentration obtained at the end of step g). This precision is important for subsequent analyses in quantification and / or characterization of the plastic particles and / or organic matter.

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

[0100] Preferably, at least during step f) of the method according to the invention, the upper, intermediate and lower chambers are arranged such that a plane passing through their openings connected to each other (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, since this maximizes the gravity flow. According to an implementation of the invention, the predefined duration of step f) may be at least 15 minutes, and is preferably 30 minutes. Such durations allow granular segregation of the plastic particles.

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

[0102] h) said second opening of said second chamber is connected to said filter, 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, said second chamber and said filter are arranged connected to each other so as to allow a gravitational flow of any fluid contained in said second chamber, and said second chamber is disconnected from said filter by disconnecting said second opening of said second chamber and said filter by means of said connection 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 variant in which the device comprises a fourth chamber, the following step h') can be added at the end of 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, 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, said second and fourth chambers are arranged connected to each other so as to allow a gravitational flow of said sample from said second chamber to said fourth chamber, and said second chamber is disconnected from said fourth chamber by disconnecting the first opening of the fourth chamber and the second opening of the second chamber by means of the connection means. The fourth chamber comprising an ad hoc filter, the liquid contained in the second chamber is evacuated. The final sample then remains in the collection chamber on concentrated. Advantageously, the walls of at least the second chamber can be rinsed before disconnecting it from the fourth chamber, to ensure complete transfer of the 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 using a cap, for example a screw-on or snap-on cap. Once disconnected from the intermediate chamber, the collection chamber can be used to transport and store the overconcentrated sample, without loss and without risk of contamination.

[0105] Advantageously, the steps of the method according to the invention can be repeated, the final sample obtained at the end of one of the repetitions of the steps of the method according to the invention becoming the initial sample of the following repetition, the overconcentration rate being able to change or not from one repetition to another, and at least the volume of the second chamber and / or of the third chamber being modified as a function of the concentration rate of the current repetition. Indeed, the volume of the lower chamber and / or of the intermediate chamber can be adapted from one repetition to another, as a function of the expected overconcentration rate.

[0106] [Fig.l] illustrates, in a schematic and non-limiting manner, an example of 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 of cylindrical shape, and connected to each other via connection means 15, 16, 25, 26, 25', 26', 35, 36. The configuration of the device according to the invention presented in this figure can be obtained at the end of the implementation of step b) of the method according to the invention, and can be used for the implementation of 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 (shown diagrammatically by the dotted line) with the opening 21 of the second chamber 20 and the opening 31 of the third chamber is in communication (shown diagrammatically 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.l] 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 method according to the invention, better stirring during step e) of the method according to the invention, as well as better granular segregation during step f) of the method according to the invention. For this design, the connection means comprise flat flanges 15, 25, 25', 35 resting on the controllable opening and closing means 23, 24 of the second chamber 20. The sealing of the assembly is ensured by O-rings 26, 26' arranged in grooves hollowed out in the flat flanges 15, 25, 25', 35, which are crushed when the flat flanges 15, 25, 25', 35 are tightened with the knife gate 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 configuration of the device of [Fig.l] 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 (Sl), 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 makes it possible to have a free volume in the assembly formed by the first chamber, the second chamber and the third chamber connected to each other, after step c) of the method according to the invention described below. This free volume is advantageous for allowing stirring of the introduced sample and / or for allowing the introduction of a liquid promoting the stirring and sedimentation of the particles constituting the initial sample.At the end of step e), which consists of stirring the three chambers 10, 20, 30 thus connected to each other, and of step f), which consists of letting the three chambers 10, 20, 30, connected to each other and arranged in such a way as to allow a gravitational flow, rest (here the three chambers will advantageously be arranged as shown in [Fig.l], i.e. such that a plane passing through their openings connected to each other is horizontal), a granular segregation operation by density will take place within the sample and the particles of plastic and / or organic matter (less dense) than the constituents of the unconsolidated solid matrix will tend to end up in the upper part of the sample, or even on its surface if the stirring time and the rest time are sufficiently long.In other words, the particles of 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] [Fig.2] illustrates a particular configuration of the example implementation of the device of [Fig.l] (thus, the common elements will not be described again), which can for example be implemented during step g) of the method according to the invention. Thus, compared to [Fig.l], the pilotable 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 10 and intermediate 20 chambers can then be disconnected from the lower chamber 30, by means of the connection means 25', 26', 35, 36 in order to isolate the overconcentrated 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] [Fig. 3] illustrates an example of implementation of the device of [Fig. 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 additionally 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 comprising a groove in which an O-ring 46 is arranged. The connection of the filter 40 to the second chamber 20 is made by tightening the flat flanges 25', 45 on the knife gate valve 24 of the second chamber 20.Such a configuration of the device according to the invention can be advantageously implemented during step h) of the method according to the invention, step 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 method according to the invention. This can be a liquid contained in the initial sample itself, or the liquid introduced during step e) of the method according to the invention, to facilitate the stirring of the sample and / or the granular segregation.

[0109] [Fig. 4] illustrates an example of implementation of the device of [Fig. 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 additionally comprising a fourth chamber 50 connected to the second chamber 20 by means of the connection means 25', 26, 55, 56. In this case, for this design, the fourth chamber 50 also comprises a flat flange 55 comprising a groove in which an O-ring 56 is arranged. 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 on the knife gate valve 24 of the second chamber 20.Such a configuration of the device according to the invention can be advantageously implemented during step h') of the method according to the invention, a step during which the contents of the second chamber 20 are transferred at the end of step g) of the method according to the invention into the fourth chamber 50, which can then act as a collection chamber. The fourth chamber 50 comprises a filter 52 at an opening (not referenced) at its base, allowing any liquid contained in the intermediate chamber 20 to be evacuated. This gives a . conditioning of the final sample. Advantageously, the fourth chamber 50 comprises 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 comprises 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 method as described above for overconcentrating a sample comprising plastic and / or organic matter particles in an unconsolidated solid matrix according to a predefined overconcentration rate, the method being carried out 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 in a sample, in particular in order to adjust to the detection thresholds of the analytical methods conventionally implemented to detect and / or characterize mesoplastics and microplastics and / or organic matter. In addition, the device according to the invention is portable and simple to use. Furthermore, the present invention can allow, in its preferred variant, the preparation and conditioning of samples to be analyzed with a fewer number of manipulations compared to the prior art, which makes it possible to avoid contamination and losses (for example, linked to the adhesion of particles to the walls of laboratory glassware, or to the filters used) which can distort the analysis of the plastic particles. Examples

[0112] The characteristics and advantages of the device and the method according to the invention will appear more clearly on reading the application example below, the objective of which is to superconcentrate plastic particles in an unconsolidated sample.

[0113] A volume of sediment IL comprising 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 knife gate valve.

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

[0115] The gate valve of the first opening of the intermediate chamber was then actuated to the closed position and a flushing of the upper chamber was carried out. carried out using distilled water. The gate valve of the first opening of the intermediate chamber was then operated in the open position, and a volume of 0.5L of distilled water was introduced via the first opening of the upper chamber.

[0116] The first opening of the upper chamber is then closed by means of a stopper to allow manual stirring of the sample in the device for 1 min. The device was then left in a vertical position for 30 min to ensure the settling of the grains constituting the sample. The coarsest grains (0.5-4 mm in diameter) made of quartz are quickly deposited at the bottom of the device. Some of the finest grains, and the plastics present, can remain in suspension in the water, which retains a turbidity.

[0117] The gate 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, whose lower opening has been previously equipped with a steel filter with a mesh size of 70 pm, is then connected under the guillotine valve of the opening. The opening of the guillotine then allows the transfer of the 0.1 L of sample through which the 0.5 L of distilled water will percolate to then be filtered through the 70 pm filter. Additional agitation is implemented to accelerate the filtration of all the water. Once all the oxygenated water has been filtered, oxygenated water is used to rinse the walls of the upper chamber and ensure the total transfer of all the particles present to the collection chamber. The collection chamber can be disconnected. A photo of the surface of the overconcentrated sample can be taken, for example. The collection chamber is then closed on its upper and lower parts using the caps.

[0119] The sample can then be studied in the laboratory for additional 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 new overconcentration step can be carried out.

Claims

Claims

1. Device for overconcentrating a sample comprising plastic particles and / or organic matter in an unconsolidated solid matrix according to a predefined overconcentration rate, 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 said 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 knife gate valve, a gate valve, a knife valve, a ball valve, a handwheel valve, or a butterfly valve.

3. Device according to one of the preceding claims, in which said device comprises means for closing said first opening (11) of said first chamber (10), for example in the form of a cover.

4. Device according to one of the preceding claims, said device further comprises a filter (40), said filter (40) being connectable 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 particles of plastic and / or organic matter as well as said unconsolidated solid matrix in said second chamber (20).

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

6. Method for overconcentrating a sample comprising particles of plastic and / or organic matter in an unconsolidated solid matrix according to a predefined overconcentration rate, said method being implemented by means of the device according to any one of the preceding claims, characterized in that at least the following steps are carried out: 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 connection 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,said second opening (12) of said first chamber (10) is opened by means of the controllable opening and closing means (23) of said second opening (12) of said first chamber (10); b) said second chamber (20) and said third chamber (30) are connected to each other by connecting said 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) said sample is introduced into said first (10), second (20) and third (30) chambers connected to each other by said first opening (11) of said first chamber (10) and so as to reach at least said first opening (21) of said second chamber (20); d) said first opening (21) of said second chamber (20) is closed by means of said controllable opening and closing means (23) of said first opening (21) of said second chamber (20) or, alternatively, said second opening (12) of said first chamber (10) is closed by means of said controllable opening and closing means (23) of said second opening (12) of said first chamber (10), the excess of said sample present in said first chamber (10) is removed, and said first opening (21) of said second chamber (20) is reopened by means of said controllable opening and closing means (23) of said first opening (21) of said second chamber (20), or alternatively, said second opening (12) of said first chamber (10) is reopened by means of said controllable opening and closing means (23) of said second opening (12) of 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) interconnected chambers and said first (10), second (20) and third (30) interconnected chambers are agitated for a first predefined duration, for example by means of a vibrating table, a rotary or translational agitator, an ultrasonic device, or even differential or equilibrium centrifugation; f) said first (10), second (20) and third (30) interconnected chambers are left to stand for a second predefined period, said first (10), second (20) and third (30) interconnected chambers being arranged so as to allow gravitational flow of at least a portion of said sample of

7.

8.

9. 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 controllable 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 superconcentrated sample is obtained in at least said second chamber (20). Method according to claim 6, in which 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. Method according to 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 together so as to allow a gravitational 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). Method according to 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 connection means (15, 16, 55, 56), 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 (10), said second (20) and fourth (50) chambers are arranged connected together so as to allow a gravitational flow of said overconcentrated sample present in said second chamber (20) towards 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 method according to one of claims 6 to 9 for overconcentrating a sample comprising particles of plastic and / or organic matter in an unconsolidated solid matrix according to a predefined overconcentration rate, said method being implemented by means of the device according to one of claims 1 to 5.

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