Detection system usable for the detection of chemical compounds, comprising a detection strip

Abstract

The invention relates to a detection system usable for the detection of one or more chemical compounds comprising: - a first support impregnated by distinct detection indicators capable of detecting the presence of said chemical compound or said chemical compounds, characterized in that each of said detection indicators is distributed on the support in the form of one or more distinct zones, the distinct zone(s) of each of said detection indicators being arranged on the support without overlapping with the distinct zone(s) of the other detection indicator(s); and - a second support intended for the deposition of the medium, the presence or absence of said chemical compound(s) to be determined, this second support being in contact with one of the faces of the first support.

Description

Title of the invention: Detection system usable for the detection of chemical compounds comprising a detection strip Technical field

[0001] The present invention relates to a novel detection system, for example, colorimetric, usable for the detection of distinct chemical compounds and to a method for detecting one or more chemical compounds implementing this detection system.

[0002] In particular, the present invention can find application for the detection of toxic chemical compounds, such as toxic war compounds and, in particular, organophosphorus compounds; toxic industrial chemical compounds (known under the name TIC); vesicants; pesticides and arsenic compounds.

[0003] Generally speaking, organophosphorus compounds are in the form of organic compounds with proven toxicity to the human body. Indeed, these compounds may be involved in the mechanism of inhibition of serine proteases and, in particular, of acetylcholinesterase, which is involved in synaptic junctions and whose deregulation of activity can prevent muscle relaxation and thus cause death by asphyxiation.

[0004] These compounds can be included in the formulation of insecticides, pesticides or even chemical combat agents (such as G series organophosphorus compounds, such as sarin or V series organophosphorus compounds, such as VX) and due to the high lethality of these compounds and their proliferation, it is important to have preliminary detection and identification systems available.

[0005] Some detection systems used to date are based on technologies involving physical measurement means, such as ion mobility spectroscopy, flame photometry, IR and Raman spectroscopies, with the difficulties that these systems require expensive complex equipment and are not necessarily adapted to all intervention environments in terms of mass and size, to which is added the expertise of the operator to be considered.

[0006] In view of what exists, the authors of the present invention have turned towards the design of a detection system usable for the detection of one or more distinct chemical compounds, which system must allow the detection of said chemical compound(s) and, when there are several, preferably, the discrimination of said compounds and meeting criteria of sensitivity, speed, portability, reliability and which can allow detection and, where appropriate, simple discrimination, such as visual discrimination with the naked eye, in particular when the detection is of a colorimetric nature. Statement of the invention

[0007] Thus, the invention relates to a detection system usable for the detection of one or more chemical compounds comprising:

[0008] -a first support impregnated with distinct detection indicators capable of detecting the presence of said chemical compound or chemical compounds, characterized in that each of said detection indicators is distributed on the support in the form of one or more distinct zones, said distinct zone(s) of each of said detection indicators being arranged on the support without overlapping with the distinct zone(s) of the other detection indicator(s); and

[0009] -a second support intended for the deposition of the medium, of which the presence or absence of said chemical compound(s) is to be determined, this second support being in contact with one of the faces of the first support.

[0010] Thanks to the presence of distinct detection indicators without there being any surface overlap between each of them, this can allow, by an appropriate choice of detection indicators, detection of one or more compounds and, ideally, when there are several chemical compounds, possibly, discrimination of distinct chemical compounds, without the detection properties (for example, the toning properties, when the detection indicators are colored indicators) of each of the indicators being altered by a mixture of the indicators, which could therefore interact with each other and bias the detection. Furthermore, the detection systems according to the invention are particularly suitable for the detection of chemical compounds in liquid form, thanks to the second support.Finally, the detection systems of the invention can allow, by the choice of appropriate colored indicators, the discrimination of distinct chemical compounds belonging to the same family, such as, by way of non-limiting example, organophosphorus compounds (such as those of the G series, of the V series or organophosphorus nerve agents recently added to Table 1 of the annex to the OPCW Convention for the Prohibition of Chemical Weapons S / 1821 / 2019 / Rev.l / Add.l (May 20, 2020)), vesicants (such as sulfur mustard, nitrogen mustard, lewisite), chemical industrial toxicants (such as ammonia, chloropicrin), pesticides.

[0011] In other words, in the case where the detection indicators are colored indicators, if they were mixed, this could induce the following disadvantages:

[0012] - mixing several colored indicators could result in a dull color;

[0013] - the colored indicators could interact with each other, making the resulting color not necessarily predictable and reactivity to the chemical compounds to be detected not guaranteed;

[0014] -the identification of chemical compounds would be less precise and less easy with the naked eye.

[0015] Before going into more detail in the description of the invention, we will clarify the following elements.

[0016] By detection indicator, it is conventionally understood a chemical substance capable of transforming upon contact with at least one chemical compound that it is desired to detect, this transformation being the sign of the presence of said at least one chemical compound, this transformation materializing by a change of color, when the detection indicator is a colored indicator (also called colorimetric detection indicator). It can also be a fluorescence indicator (or fluorophore), depending on its nature.More specifically, when the detection indicator is a colored indicator, this corresponds, classically, to a chemical substance which takes on at least one characteristic color in the presence of a chemical compound, i.e., in other words, a chemical substance which has at least two colored states, one colored state existing when the chemical substance is not in the presence of the chemical compound to be detected and at least one other colored state when the chemical substance is in the presence of the chemical compound(s) to be detected. The detection indicator may consist of one or more compounds allowing detection.

[0017] By "without overlapping", it is understood, conventionally, that the distinct zone(s) of each of the detection indicators do not mix with the distinct zone(s) of the other detection indicators, which does not exclude the distinct zone(s) of each detection indicator from being able to be, in whole or in part, juxtaposed with the distinct zone(s) of the other detection indicator(s).

[0018] As defined above, the detection system usable for the detection of one or more chemical compounds comprises a first support impregnated with distinct detection indicators capable of detecting the presence of said chemical compound or chemical compounds, characterized in that each of said detection indicators is distributed on the support in the form of one or more distinct zones, said distinct zone(s) of each of said detection indicators being arranged on the support without overlapping with the distinct zone(s) of the other detection indicator(s).

[0019] More specifically, each of said detection indicators is distributed on the support in the form of one or more distinct zones, said distinct zone(s) being able to be in substantially circular, rectangular or square shapes, it being understood that other shapes may be considered, provided that there is no overlap between the separate areas for separate detection indicators.

[0020] The first support constituting the detection system may be, in particular, a porous support and, more specifically, a paper support, it being understood that this support must be capable of being impregnated by the different detection indicators to form the distinct zones.

[0021] The first constituent support conventionally comprises two faces, an upper face comprising the distinct zones comprising the detection indicators and a lower face opposite the upper face, the lower face being the face in contact with the second support.

[0022] Advantageously, the distinct zones can be partitioned by obstructing the porosity of the first support on the zones which are not the distinct zones, the porosity being able to be obstructed, more specifically, for example, by wax, paraffin, a polydimethylsiloxane or any other means for obstructing the porosity. The porosity thus obstructed makes it possible to limit access to the analyte (namely, the medium, generally liquid, in which one wishes to know the presence or absence of compounds to be analyzed) to the zones thus obstructed and thus create a fluid circuit allowing privileged access of the analyte to the distinct zones comprising the detection indicators, which are not obstructed.

[0023] The first support may be in the form of a strip, as will be illustrated in particular embodiments illustrated in attached figures.

[0024] The first support may comprise at one of its ends, a hollowed-out zone, thus giving direct access to the second support, this hollowed-out zone thus allowing the direct deposition of the analyte on the second support on the zone of the latter opposite the hollowed-out zone of the first support. This hollowed-out zone may constitute a “reservoir” for the analyte which will, in addition to being in contact with the second support, be thus retained in this zone without risk of flow to the outside.

[0025] More specifically, the detection system may comprise, as detection indicators, colored indicators allowing colorimetric detection.

[0026] Depending on the chemical compounds to be detected and possibly discriminated, it is understood that the person skilled in the art, in order to design the detection system in accordance with the invention, will choose, when the detection indicators are colored indicators, preferably appropriate colored indicators by making a selection based in particular on the fact that the colored indicators chosen must, of course, exhibit at least one colorimetric change in the presence of the chemical compound that it is desired to detect.

[0027] Depending on the chemical compounds that are to be detected, the colored indicators may be chosen from anthraquinone compounds, azo compounds, triarylmethane compounds, xanthene compounds, indigo compounds, metal complexes, compounds comprising at least one stilbene group, coumarin compounds, compounds comprising at least one cyanine group, compounds comprising at least one phthalocyanine group, compounds comprising at least one porphyrin group, compounds comprising at least one hydrazone group.

[0028] As examples of anthraquinone compounds, mention may be made of 1,4-dihydroxyanthraquinone, 1-aminoanthraquinone, carminic acid, 1,5-diaminoanthraquinone, 1,2-diaminoanthraquinone, 1,4-diamino-5-nitroanthraquinone, 1,4,5,8-tetraaminoanthraquinone (Disperse Blue 1), 1-methylamino-4-(2-hydroxyethyl)aminoanthraquinone (Disperse Blue 3), 1-amino-2-methylanthraquinone (Disperse Orange 11), 1,4-Z?A-(p-tolylamino)anthraquinone (Solvent Green 3).

[0029] As examples of azo compounds, mention may be made of 10-(2',4'-dinitrophenylazo)-9-phenanthrol, disodium 6-hydroxy-5-[(2-methoxy-5-methyl-4-sulfophenyl)azo]-2-naphthalenesulfonate (also known as Allura Red AC), 4-dimethylaminoazobenzene (also known as methyl yellow), 4-(2-carboxyphenylazo)-N,N-dipropylaniline (also known as "Propyl red" in English terminology), 3-(diethylamino)-7-{(E)-[4-(dimethylamino)phenyl]diazenyl}-5-phenylphenazin-5-ium chloride (also known as "Janus Green B"), N,N-dimethyl-4,4'-azodianiline, N-ethyl-l-((4-phenyldiazenyl)phenyl)diazenyl)naphthalen-2-amine (also known as "Sudan Red 7B"), amaranth, 4-[[3-[(2,4-diaminophenyl)diazenyl]phenyl]diazenyl]benzene-l,3-diamine dihydrochloride (also known as "Bismarck Brown Y"), disodium 4-hydroxy-3-[(4-sulfo-l-na phthalenyl)azo]-l-naphthalenesulfonate (also known as "Chromotrope FB"),benzidinediazo-bis-l-naphthylamine-4-sulfonic acid (also known as "Congo Red"), 2,2'-[4-(4-Aminophenylazo)phenylimino]diethanol (also known as "Disperse Black 9" in English terminology), 2,2'-[[4-[(4-nitrophenyl)azo]phenyl]imino]bisethanol (also known as "Disperse Red 19" in English terminology), sodium (4Z)-4-[(l-hydroxynaphthalen-2-yl-hydrazinylidene]-7-nitro-3-oxo Y-naphthalene-l-sulfonate (also known as "Eriochrome Black T"), 4'-(4-(diethylamino)phenylazo)acetophenone, 4-[(E)-(4-nitrophenyl)diazenyl]-N-phenylaniline (also known as "Disperse Orange 1"), helianthine (also called methyl orange), 4-(4-nitrophenylazo)aniline (also called "Disperse Orange 3"), 4-[4-(phenylazo)-l-naphthylazo]phenol (also called "Disperse Orange 13"), 3-[N-ethyl-4-(4-nitrophenylazo)phenylamino]propionitrile (also called "Disperse Orange 25"), 4-amino-5-hydroxy-3-(4-nitrophenylazo)-6-(phenyl , sodium lazo)naphthalene-2,7-disulfonate (also known as "Naphthol Blue Black"), (2,2-dimethyl-1,3-dihydroperimidin-6-yl)-(4-phenylazo-1-naphthyl)diazene (also known as "Sudan Black B" in English terminology), disodium 6-hydroxy-5-[(4-sulfonatophenyl)azo]naphthalene-2-sulfonate (also known as "Orange Yellow S"), tartrazine, Evans Blue, 4-[4-(phenylazo)phenylazo]-o-cresol (also known as "Disperse Yellow 7" in English terminology), 4'-nitro-4-dimethylaminoazobenzene.

[0030] As examples of triarylmethane compounds, mention may be made of aniline diammonium blue, bromophenol blue, m-cresol violet, cresol red, gentian violet (also called "Crystal Violet" in English terminology), chlorophenol red, sodium salt of (4-(a-(p-(diethylamino)phenyl)-2,4-disulfobenzylidene)-2,5-cyclohexadien-l-ylidene)diethylammonium hydroxide (also called "Patent blue V sodium salt"), methyl blue, rosolic acid, pyrocatechol violet, brilliant green BS, pararosaniline base, fuchsin, thymol blue, 4-(dimethylamino)-a-[4-(dimethylamino)phenyl]-a-phenyl-benzenemethanol.

[0031] As examples of xanthenic compounds, mention may be made of [9-(2-carboxyphenyl)-6-diethylamino-3-xanthenylidene]-diethylammonium chloride (also called “Rhodamine 610”), rhodamine 6G optionally in the form of perchlorate salt, rhodamine B, sulforhodamine 101 hydrate, fluoresceinamine (in particular Isomer I), rhodamine 110 chloride.

[0032] As examples of indigo compounds, mention may be made of indigo.

[0033] As examples of metal complexes, mention may be made of trisodium 5-nitroso-6-oxidonaphthalene-2-sulfonate complexed with iron (III) (also known as “Naphthol Green B”).

[0034] As examples of compounds comprising at least one stilbene group, mention may be made of the dye known under the English terminology “Fluorescent Brightener 28”.

[0035] As examples of coumarin compounds, mention may be made of 7-amino-4-(trifluoromethyl)coumarin, 7-amino-4-methylcoumarin, 3-(2-N-Methylbenzimidazolyl)-7-N,N-diethylaminocoumarin (also called "Coumarin 30"), 2,3,6,7-tetrahydro-10-(3-pyridyl)-1H,5H,11H-[1]benzopyrano[6,7,8-11]quinolizin-11-one (also called "Coumarin 510"), 3-(2-Benzothiazolyl)-7-(diethylamino)coumarin (also called "Coumarin 6").

[0036] As examples of compounds comprising a cyanine group, mention may be made of indocyanine green, 5,5'-dichloro-11-diphenylamino-3,3'-diethyl-10,12-ethylenethiatricarbocyanine perchlorate (also known as IR140).

[0037] As examples of compounds comprising a phthalocyanine group, mention may be made of iron (III) phthalocyanine chloride, iron (III) phthalocyanine-4,4',4”,4”'-tetrasulfonic acid, 1,2,3,4,8,9,10,11,15,16,17,18,22,23,24,25-hexadecafluoro-29H,31H-phthalocyanine.

[0038] The detection system also comprises a second support intended for depositing the medium, the presence or absence of at least one chemical compound of which is to be determined and the colored indicator of which is present on the first support, this second support being in contact with one of the faces of the first support (conventionally, the lower face opposite the upper face, which is occupied by the distinct zones of the colored indicators).

[0039] This second support advantageously allows the diffusion or migration by capillarity of the medium deposited thereon, so that it can reach the different distinct zones mentioned above of the first support and allow, if necessary, the detection of one or more compounds possibly contained in this analyte and sensitive to the colored indicators constituting the distinct zones.

[0040] This second support may be made of a material comprising (or consisting of) an entanglement of fibers, such as fibers chosen from cellulose fibers (in particular those used in filter papers for laboratories or in papers intended to be used in chromatographic techniques), glass fibers, synthetic polymer fibers, such as polyester fibers, and mixtures thereof, this entanglement being able to form a non-woven material.

[0041] This second support may be in the form of a strip, in particular when the first support is also in the form of a strip, and may in particular have the same dimensions as the first support, whereby it completely covers one of the faces of the first support (generally the lower face of the first support opposite the upper face, on which the aforementioned distinct zones are affixed).

[0042] This second support, in particular when it is in the form of a strip, may comprise, at the level of the face in contact with the first support, two opposite lateral strips located on the two largest sides of the strip, these two strips being waterproof strips and providing a central zone devoid of these strips and constituting a space for circulation of the medium, of which it is desired to determine the presence or absence of said chemical compound(s). This circulation space advantageously constitutes a space for circulation of the medium towards the distinct zones of the first support and makes it possible to prevent the medium from escaping from the sides thanks to the presence of these strips. These waterproof strips may result from the obstruction of the porosity of the second support in these places, for example, by application of a wax, a paraffin, a polydimethylsiloxane, an adhesive (which also makes it possible to gluing the first support and the second support to each other) or any other means to obstruct the porosity.

[0043] The second support placed in contact with the first support may comprise a tab emerging from the stack of the first support and the second support, this tab serving as a deposition zone for the analyte and being conventionally made of a material identical to that constituting the rest of the support.

[0044] The detection systems of the invention may further comprise a sealed layer in contact with the second support via the face opposite that which is in contact with the first support (this opposite face being able to be called the lower face in opposition to the upper face which is in contact with the first support), which means, in other words, that the second support is sandwiched between the first support and the sealed layer, this arrangement being particularly favorable, in order to protect an operator who would handle the strip from any direct contact with the chemical compounds to be detected and in order to increase the capillary forces which will more quickly drive the analyte towards the inside of the second support. This sealed layer advantageously has the same dimensions as the second support, whereby it completely covers one of the faces of the second support (conventionally, the lower face of the second support).

[0045] Indeed, without being bound by theory, for a vertical deposition of the analyte (i.e. by vertical immersion of one end of the detection system in the analyte), the second support takes approximately 10 minutes to be impregnated with a colored solution based on dimethyl sulfoxide (DMSO) for a system where the second support is not sandwiched, compared to 4 minutes for a system where the second support is sandwiched. For a horizontal deposition of the analyte (in particular, for systems comprising a second support with a tab which serves as an analyte deposition zone, for example, by deposition of the analyte using a pipette), the second support takes approximately 2 minutes to be impregnated with a system where the second support is sandwiched.

[0046] The detection systems of the invention may further comprise a transparent layer in contact with the first support via the face opposite that which is in contact with the second support (this face being able to be called the upper face in opposition to the lower face which is in contact with the second support), this layer making it possible, in addition to isolating the analyte from the outside, to visualize, where appropriate, the chromatic change at the level of the distinct zones present on the first support.

[0047] The waterproof layer and the transparent layer have the function, in particular, of completely encapsulating the detection system while allowing easier handling of the latter and limiting the risks of contamination linked to the handling of the system.

[0048] In summary, thus, the systems of the invention can be defined otherwise as a multilayer stack comprising a first support and a second support in contact with each other, advantageously, a sealed layer in contact with the lower face of the second support and a transparent layer in contact with the upper face of the first support, systems of this type being illustrated in the figures which are commented on below and which illustrate, in particular:

[0049] -detection systems intended for vertical use, namely, by dipping, vertically, said detection systems via one of the ends giving access to the second support into the analyte (such as the system shown in [Fig.l]);

[0050] -detection systems intended for horizontal use, namely, by depositing, horizontally, on said detection systems via one of the ends giving access to the second support, one or more drops of the analyte (such as the systems shown in Figures 2 and 3).

[0051] More specifically, as systems intended for vertical use, mention may be made of the system shown in exploded view and in compact view in [Fig.l] comprising:

[0052] -the first support 5 being in the form of a strip comprising 4 distinct circular zones (respectively 7, 9, 11 and 13) each comprising a distinct detection indicator, the first support being extended at one of its ends 15 by a tab 17;

[0053] -the second support 19 being in the form of a strip of dimensions similar to the strip of the first support, which strip is also extended at one of its ends 21 by a tab 23, contact with the analyte taking place at the level of this tab, which analyte then progressing in the direction of the arrow by capillarity;

[0054] - a transparent plate 25 in the form of a strip of dimensions similar to those of the first support and the second support, which strip is also extended at one of its ends 27 by a tab;

[0055] -a waterproof plate 31 in the form of a strip of dimensions similar to those of the first support and the second support, which strip is also extended at one of its ends 33 by a tab 35.

[0056] As a system intended for horizontal use, mention may be made of the system shown in exploded view and in compact view in [Fig.2] comprising:

[0057] -the first support 37 being in the form of a strip comprising 6 distinct rectangular zones (respectively 39, 41, 43, 45, 47 and 49) each comprising a distinct detection indicator;

[0058] -the second support 51 being in the form of a strip of dimensions similar to the strip of the first support, which strip extends to one of its ends 53 by a tab 55, contact with the analyte being made at the level of this tab by depositing one or more drops of said analyte, which analyte then progressing in the direction of the arrow by capillarity;

[0059] - a transparent plate 57 in the form of a strip of dimensions similar to those of the first support;

[0060] -a waterproof plate 59 in the form of a strip of dimensions similar to that of the second support, which strip is extended at one of its ends 61 by a tab 63, said strip having dimensions similar to the second support.

[0061] Finally, as a system intended for horizontal use, mention may also be made of the system shown in exploded view and in compact view in [Fig.3] comprising:

[0062] -the first support 65 being in the form of a strip comprising 4 distinct rectangular zones (respectively 67, 69, 71, and 73) each comprising a distinct detection indicator and comprising at one end 75 a hollow zone 77;

[0063] -the second support 79 being in the form of a strip of dimensions similar to the strip of the first support, contact with the analyte being made by means of the hollowed-out zone 77 of the first support, which is opposite the second support, which analyte then progressing in the direction of the arrow by capillarity;

[0064] - a transparent plate 81 in the form of a strip of dimensions similar to those of the first support and also comprising a hollowed-out zone 82 opposite the hollowed-out zone 77 of the first support;

[0065] -a waterproof plate 83 in the form of a strip of dimensions similar to those of the first support, the second support and the transparent plate.

[0066] The detection systems in accordance with the invention may be prepared by a method comprising, for each of the detection indicators, a separate step of deposition on the first support by projecting an ink comprising the detection indicator concerned, which means in other words, that the method comprises as many deposition steps mentioned above as there are detection indicators, it being understood that each of the detection indicators is deposited so as not to mix with the other detection indicator(s).

[0067] To do this, each of the detection indicators can be deposited according to a specific deposition mask, each of the deposition masks being designed so that the deposited points of each of the detection indicators do not overlap with those of the other detection indicator(s).

[0068] Concerning the deposition techniques that can be envisaged, these may be any deposition techniques allowing localized deposition, such as inkjet printing, screen printing, offset printing, heliography, flexography.

[0069] Finally, the invention also relates to a method for detecting the presence or absence of one or more chemical compounds comprising the following steps:

[0070] - a step of bringing the medium(s) in which the presence or absence of said chemical compound(s) is to be detected into contact with the detection system as defined above;

[0071] - a step of deduction, as a function of the possible transformation signal(s) of all or part of the detection indicators (for example, chromatic changes, when the detection indicator(s) are colored indicators), of the presence or absence of said compound(s).

[0072] This contacting step may consist of depositing one or more separate drops of the analyte on the surface of the detection system, for example, via a pipette, in particular when the system is suitable for horizontal use, or may consist of immersing one of the ends of the detection system so that the analyte comes into contact with the second support, this method of contacting being suitable for a system suitable for vertical use.

[0073] It is understood that the detection system to be used in the context of the aforementioned method must be capable of detecting the chemical compound(s) whose absence or presence is to be determined.

[0074] Between the contacting step and the deduction step, a waiting time may be provided so that, if necessary, the migration of the chemical compound(s) to be detected can take place and the signal(s) (such as chromatic changes) can also take place.

[0075] Concerning the deduction step, when the detection indicators are colored indicators, the operator may rely on a colorimetric scale associated with the detection system, which will define, for all the chemical compounds likely to be detected by the system, the corresponding chromatic shift, this colorimetric scale being able to be determined, by prior tests, for each of the systems and the chemical compounds intended to be detected by said systems. The deduction may be done by the naked eye or, if necessary, via optoelectronic means.

[0076] The compounds capable of being detected by the method of the invention may be toxic chemical compounds, such as toxic war compounds and, in particular, organophosphorus compounds; toxic industrial chemical compounds (known under the name TIC); vesicants; pesticides and arsenic compounds.

[0077] The invention finally also relates to a colorimetric detection kit which can be used for the detection of one or more chemical compounds comprising the following elements:

[0078] - a detection system according to the invention and as defined above and in which the detection indicators are colored indicators; and

[0079] - a colorimetric scale allowing the correspondence to be made between the observed chromatic change and the chemical compound(s) detected.

[0080] The color scale may be located at the level of the first support, for example, on either side of the distinct zones with at the level of each distinct zone, for example, on the left, the initial color of the colored indicator and on the right, the possible color(s) for the colored indicator.

[0081] Other characteristics and advantages of the invention will appear more clearly on reading the additional description which follows, which relates to an example of preparation of a detection system in accordance with the invention.

[0082] Of course, the following example is given only as an illustration of the subject of the invention and in no way constitutes a limitation of this subject. Brief description of the drawings

[0083] [Fig.l], already commented on, schematically illustrates an example of a detection system suitable for vertical use.

[0084] [Fig.2], already commented on, schematically illustrates an example of a system of detection suitable for horizontal use.

[0085] [Fig.3], already commented on, illustrates schematically another example of a system of detection suitable for horizontal use.

[0086] DETAILED DESCRIPTION OF PARTICULAR EMBODIMENTS EXAMPLE

[0087] The example below illustrates the implementation of the colorimetric detection systems in accordance with the invention, these detection systems being in accordance with what is already described above for [Fig.3] with the following elements:

[0088] -the first support 65 being in the form of a strip comprising 4 distinct rectangular zones (respectively 67, 69, 71, and 73) each comprising a distinct colored indicator (Bromocresol Green; 2,4- / Vs|p-(dimcthylamino jstyryl] quinoline; Disperse Black 9 and Disperse Yellow 7) and comprising at one end 75 a hollowed-out zone 77;

[0089] -the second support 79 being in the form of a strip of dimensions similar to the strip of the first support, which strip, the contact with the analyte being made by means of the hollowed-out zone 77 of the first support, which is in regard to the second support, which analyte then progresses in the direction of the arrow by capillarity;

[0090] - a transparent layer 81 in the form of a strip of dimensions similar to those of the first support and the second support but not extending as far as the hollowed-out deposition zone;

[0091] -a waterproof layer 83 in the form of a strip of dimensions similar to those of the first support, of the second support.

[0092] These detection systems are prepared as follows:

[0093] - an operation of drawing the three layers (first support, second support, waterproof layer);

[0094] - a printing operation of these three layers on a filter paper (420*520 mm, thickness of 0.16 mm, surface mass of 65 g / m2, porosity of 7-10 pm, Product reference: VWR 115-2319) using a Xerox printer (ColorCube 8580);

[0095] - an operation of creating the partitioning by migration of the ink from the wax printed on the surface by the printer into the porosities of the filter paper during controlled heating on a hot plate;

[0096] - an operation of depositing with a pipette the 4 colored indicator solutions in the dedicated zones (respectively, zones 67, 69, 71, and 73) on the layer acting as the first support);

[0097] - an operation of gluing the waterproof layer only on the edges of the face where the layer acting as a second support is intended to be deposited, the central part of the waterproof layer being protected so as not to be glued and to prevent the glue used (3M spray glue) from being in contact with the migration zone of the second support and causing an unwanted chromogenic change in the colored indicators present on the first support;

[0098] - an operation of gluing the layer acting as a second support at the level of the areas previously covered with wax, excluding the central area known as the migration area, the glue being deposited on the face intended to be in contact with the first support;

[0099] - an operation of depositing on the second support the layer acting as the first support and on which the colored indicators have been previously deposited;

[0100] - an operation of depositing the transparent layer in the form of a very sticky film (High Tack PE / barrier / PEN from Oike).

[0101] Four detection systems of this type are prepared and on which are deposited respectively 5 pL of Sarin (called GB, CAS No. 107-44-8), 5 pL of VX (CAS No. 50782-69-9), 5 pL of sulfur mustard gas (called HD, CAS No. 505-60-2) and 5 pL of lewisite (called Ll, CAS No. 541-25-3).

[0102] It appears that the colored indicators change differently for these substances, the change being different for Sarin, VX, sulfur mustard gas or Lewisite L1, with however a similar response for the two vesicants, sulfur mustard gas and Lewisite L1. Detection systems according to this example could therefore be used for discrimination between Sarin, VX and the two vesicants (sulfur mustard gas and Lewisite L1).

Claims

Claims

1. Detection system usable for the detection of one or more chemical compounds comprising: - a first support impregnated with distinct detection indicators capable of detecting the presence of said chemical compound or said chemical compounds, the detection indicators being colored indicators chosen from anthraquinone compounds, azo compounds, xanthene compounds, indigo compounds, metal complexes, compounds comprising at least one stilbene group, coumarin compounds, compounds comprising at least one cyanine group, compounds comprising at least one phthalocyanine group, compounds comprising at least one porphyrin group and compounds comprising at least one hydrazone group, characterized in that each of said detection indicators is distributed on the support in the form of one or more distinct zones,said distinct zone(s) of each of said detection indicators being arranged on the support without overlapping with the distinct zone(s) of the other detection indicator(s); and - a second support intended for the deposition of the medium, of which the presence or absence of said chemical compound(s) is to be determined, this second support being in contact with one of the faces of the first support, in which the distinct zones are partitioned by obstructing the porosity of the first support at the level of the zones which are not the distinct zones.,

2. A detection system according to claim 1, wherein said distinct zone(s) are in substantially circular, rectangular or square shapes.

3. A detection system according to claim 1 or 2, wherein the first support is a porous support.

4. A detection system according to any preceding claim, wherein the first medium is a paper medium.

5. A detection system according to any preceding claim, wherein the first support is in the form of a strip.

6. Detection system according to any one of the preceding claims, in which the first support comprises at one of its ends, a hollowed-out zone thus giving direct access to the second support.

7. Detection system according to any one of the preceding claims, in which the second support is made of a material comprising an entanglement of fibers chosen from cellulose fibers, glass fibers, synthetic polymer fibers and mixtures thereof.

8. A detection system according to any preceding claim, wherein the second support is in the form of a strip.

9. Detection system according to any one of the preceding claims, in which the second support, when it is in the form of a strip, comprises, at the level of the face in contact with the first support, two opposite lateral strips located on the two largest sides of the strip, these two strips being sealed strips and providing a central zone devoid of these strips and constituting a space for circulation of the medium, of which it is desired to determine the presence or absence of said chemical compound(s).

10. A detection system according to any preceding claim, wherein the second support comprises a tab emerging from the stack of the first support and the second support, this tab serving as an analyte deposition zone.

11. Detection system according to any one of the preceding claims, further comprising a sealing layer in contact with the second support via the face opposite that which is in contact with the first support.

12. A detection system according to any preceding claim, further comprising a transparent layer in contact with the first support via the face opposite that which is in contact with the second support.

13. A method of preparing a detection system as defined in claim 1, comprising, for each of the detection indicators, a separate step of depositing on the first support by projecting an ink comprising the detection indicator concerned.

14. Method for detecting the presence or absence of one or more chemical compounds comprising the following steps: - a step of bringing the medium(s), in which the presence or absence of the said chemical compound(s) is to be detected, into contact with a detection system as defined according to any one of claims 1 to 12; - a step of deducing, as a function of the possible transformation signal(s) of all or part of the detection indicators, the presence or absence of the said compound(s).

15. A method according to claim 14, which is a method for detecting the presence or absence of at least one chemical compound selected from toxic chemical compounds; toxic industrial chemical compounds; vesicants; pesticides and arsenic compounds.

16. A colorimetric detection kit usable for the usable detection of one or more chemical compounds comprising the following elements: - a detection system as defined according to any one of claims 1 to 12; and - a colorimetric scale making it possible to establish the correspondence between the observed color change and the chemical compound(s) detected.

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