Colorimetric detection device in the form of a sprayer for the detection of chemical compounds

Abstract

The invention relates to a colorimetric detection device for detecting at least one chemical compound, which is in the form of a sprayer containing a composition which comprises a dispersing phase in which at least one coloured indicator capable of changing colour in the presence of the chemical compound is dispersed. The coloured indicator is present in the dispersing phase in the form of a plurality of solid particles which are impregnated with the coloured indicator or in which the coloured indicator is encapsulated. The invention also relates to a method for detecting the presence or absence of at least one chemical compound that employs a device as described above. Applications: detection of chemical compounds, toxic warfare compounds or toxic chemical-industry compounds.

Description

[0001] COLORIMETRIC DETECTION DEVICE IN THE FORM OF A SPRAYER FOR THE DETECTION OF CHEMICAL COMPOUNDS

[0002] Description

[0003] TECHNICAL FIELD

[0004] The present invention relates to a colorimetric detection device.

[0005] More specifically, the invention relates to a colorimetric detection device, in the form of a sprayer for the detection of chemical compounds using colored indicators.

[0006] It also relates to a method for detecting the presence or absence of chemical compounds, by implementing the colorimetric detection device.

[0007] The present invention may find application for the detection of toxic chemical compounds, such as toxic warfare compounds or toxic industrial chemical compounds (known as TIC).

[0008] STATE OF THE PRIOR ART

[0009] NRBC-E (nuclear, radiological, biological, chemical and explosive) risks pose a significant threat to the civilian population. They result from industrial accidents, criminal acts (such as the use of toxic weapons), and natural or environmental disasters in which toxic compounds are released into the environment.

[0010] It is therefore important to be able to detect the presence of such toxic compounds in the event of NRBC-E risks.

[0011] To date, it is possible to use a detector paper comprising colored indicators of the toxic compounds to be detected, but this paper does not allow a resistant deposition of these colored indicators on a surface likely to be contaminated and, in particular, on surfaces that are too complex. Furthermore, sprays have been proposed as colorimetric detectors. For example, Shrishty Bakshi et al. (Advanced Functional Materials, 2022,32, 2103496, hereinafter [1]) have developed a spray comprising a polyprolactone polymer and one or two colored indicators in solution in chloroform for the detection of Fe ions. 2+ , Fe ions 3+and ammonia only. This spray is sprayed in the form of nanofibers onto various types of surfaces, simply using compressed gas. The nanofibers are generated only during the spraying step. Furthermore, since the colored indicators included in this spray are dissolved in chloroform, they can easily interact with each other before being sprayed in the form of nanofibers.

[0012] The inventors therefore set themselves the goal of providing a colorimetric detection device which does not have the above drawbacks, that is to say a device which makes it possible to detect and, ideally, discriminate more complex chemical compounds (such as toxic chemical compounds) on a complex surface and in which any interaction between the colored indicators is avoided.

[0013] They also set themselves the goal of providing such a device without the need to use a solvent that is hazardous to health and the environment, such as a chlorinated solvent.

[0014] STATEMENT OF THE INVENTION

[0015] The invention therefore relates, firstly, to a colorimetric detection device for the detection of at least one chemical compound, in the form of a spray and containing a composition which comprises a dispersing phase in which is dispersed at least one colored indicator capable of changing color in the presence of the chemical compound, characterized in that the colored indicator is present in the dispersing phase in the form of a plurality of solid particles which are impregnated with the colored indicator or in which the colored indicator is encapsulated.

[0016] In the following, the device of the invention can more simply be called “spray”.

[0017] It should be noted that the device of the invention may be capable of detecting several chemical compounds, in which case the composition contained in this device comprises a dispersing phase in which several colored indicators are dispersed in the form of a plurality of solid particles.

[0018] Preferably, each solid particle is impregnated with only one colored indicator or encapsulates only one colored indicator when several different colored indicators are dispersed in the dispersing phase.

[0019] A "colored indicator" means a 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 exhibits at least two color states, one color state existing when the chemical substance is not in the presence of the chemical compound to be detected and at least one other color state when the chemical substance is in the presence of the chemical compound to be detected, the transition from one color state to the other being visible to the naked eye.

[0020] The fact that the colored indicator is present in the dispersing phase in the form of a plurality of solid particles, makes it possible in particular to limit the migration of the colored indicator in the dispersing phase and thus to limit any interaction between colored indicators in this dispersing phase. Thus, the device of the invention also has the advantage of being able to use different colored indicators in the same composition contained in such a device, since these colored indicators will not be able to interact with each other. This then allows the detection and, even better, the discrimination of chemical compounds, when several chemical compounds are present.

[0021] The term "different colored indicators" means that each colored indicator reacts to at least one different specific chemical compound.

[0022] The particles impregnated with the colored indicator or encapsulating the colored indicator may be made of an inorganic material, for example based on silica, alumina, zinc oxide, titanium oxide or zeolite, preferably based on silica, or organic, in which case they are typically made of a polymeric or copolymeric material, crosslinked or not.

[0023] Among these particles, preference is given to particles made of an organic material and, more specifically, of a polymeric or copolymeric material.

[0024] Such particles can be obtained by polymerization of one or more monomers - this polymerization can then be a mass, solution, suspension, dispersion or emulsion polymerization, induced by heat or UV, in the presence or absence of a polymerization initiator - or by solubilization / precipitation of one or more polymers or copolymers in an appropriate solvent.

[0025] In the case where the particles are made of a crosslinked polymeric or copolymeric material, then this crosslinking can result:

[0026] - functionalization of the monomer(s) prior to polymerization, in which case the polymerization is accompanied by crosslinking;

[0027] - functionalization of the monomer(s) after polymerization, in which case the polymerization and crosslinking are carried out in two stages; or

[0028] - in the case of a copolymeric material, a copolymerization of one or more monofunctional monomers and one or more multifunctional monomers.

[0029] Crosslinking helps to limit the migration of the colored indicator into the dispersing phase as much as possible.

[0030] According to the invention, the particles made of a polymeric or copolymeric material comprise at least one monomer preferably chosen from ethylene, methyl (meth)acrylate and trimethylolpropane triacrylate and, better still, chosen from methyl (meth)acrylate and trimethylolpropane triacrylate.

[0031] In any event, the solid particles are preferably microparticles, i.e. they have a number average size of between 0.1 pm and 100 pm and, more preferably, between 5 pm and 50 pm. This number average size can be determined by laser diffraction particle size analysis, for example using a laser particle size analyzer such as that marketed by Malvern Panalytical, under the reference Mastersizer™ 3000.

[0032] In this regard, it is specified that "size" means the largest of the three dimensions of the microparticles.

[0033] The colorimetric detection device according to the invention is particularly suitable for the detection of chemical compounds in the form of a liquid or a solid. This device allows easy reading of a possible change in color (or so-called colorimetric shift) of the colored indicator, when it is in the presence of the chemical compound, even when the latter is only present in small quantities, for example in the form of a droplet.

[0034] It is also particularly suitable for detecting the chemical compound present on a complex or flexible surface, such as on the surface of a tire, clothing or even a shoe.

[0035] Typically, the dispersing phase is a liquid phase.

[0036] More specifically, the dispersant phase of the composition contained in the device may be an aqueous or organic phase and may optionally comprise a surfactant.

[0037] The composition contained in the device, intended to be sprayed onto a surface, can subsequently be removed from this surface mechanically and / or using water or suitable solvents.

[0038] For example, when the dispersant phase of the composition contained in the device is an aqueous phase, then the composition can be removed from the surface by simple cleaning with water, whereas when the dispersant phase is an organic phase, the composition can be removed from the surface by rubbing and / or using n-decane.

[0039] This can be extremely interesting in the context of a potential reuse of the surface.

[0040] On the other hand, the colored indicator is chosen so that it obviously presents at least one colorimetric change in the presence of the chemical compound that we wish to detect.

[0041] Better still, when several colored indicators are used, they are advantageously chosen so that each of them exhibits at least one contrasting colorimetric change relative to each other when they are in contact with at least one specific chemical compound. This allows discrimination of the chemical compounds, when several chemical compounds are present. These colored indicators may be those which advantageously exhibit a similar initial color (i.e. without exposure to one or more chemical compounds), and, preferably, a light color (for example, in shades of pale yellow), or even are colorless.

[0042] Depending on the chemical compound to be detected, the colored indicator 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.

[0043] Examples of anthraquinone compounds include 1,4-dihydroxyanthraquinone, 1-aminoanthraquinone, carminic acid, 1,5-diaminoanthraquinone, 1,2-diaminoanthraquinone, l,4-diamino-5-nitroanthraquinone, 1,4,5,8-tetraaminoanthraquinone (Disperse Blue 1), 1-methylamino-4-(2-hydroxyethyl)aminoanthraquinone (Disperse Blue 3), l-amino-2-methylanthraquinone (Disperse Orange 11), l,4-b / s-(p-tolylamino)anthraquinone (Solvent Green 3).

[0044] Examples of azo compounds include 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), 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-naphthalenyl)azo]-l-naphthalenesulfonate (also known as "Chromotrope FB"),benzidinediazo-bis-l-naphthylamine-4-sulfonic acid (also known as “Congo Red”), 2,2'-[4-(4-,

[0045] [Aminophenylazo]phenylimino]diethanol (also called "Disperse Black 9" in English terminology), 2,2'-[[4-[(4-nitrophenyl)ado]phenyl]imino]bisethanol (also called "Disperse Red 19" in English terminology), sodium (4Z)-4-[(l-hydroxynaphthalen-2-yl-hydrazinylidene]-7-nitro-3-oxo Y-naphthalene-l-sulfonate (also called "Eriochrome Black T"), 4'-(4- (diethylamino)phenylazo)acetophenone, 4-[(E)-(4-nitrophenyl)diazenyl]-N-phenylaniline (also called "Disperse Orange 1" in English terminology), helianthine (also called methyl orange), 4-(4-nitrophenylazo)aniline (also called " Disperse Orange 3" according to English terminology), 4-[4-(phenylazo)-l-naphthylazo]phenol (also called "Disperse Orange 13" according to English terminology), 3-[N-ethyl-4-(4-nitrophenylazo)phenylamino]propionitrile (also called "Disperse Orange 25" according to English terminology), 4-amino-5-hydroxy-3-(4-nitrophenylazo)-6- (phenylazo)naphthalene-2,Sodium 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.,

[0046] Examples of triarylmethane compounds include diammonium aniline blue, bromophenol blue, m-cresol violet, cresol red, gentian violet (also known as "Crystal Violet" in English terminology), chlorophenol red, (4-(a-(p-(diethylamino)phenyl)-2,4-disulfobenzylidene)-2,5-cyclohexadien-l-ylidene)diethylammonium hydroxide sodium salt (also known as "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.

[0047] Examples of xanthene compounds include [9-(2-carboxyphenyl)-6-diethylamino-3-xanthenylidene]-diethylammonium chloride (also known as "Rhodamine 610"), rhodamine 6G, possibly in the form of perchlorate salt, rhodamine B, sulforhodamine 101 hydrate, fluoresceinamine (in particular Isomer I), rhodamine 110 chloride.

[0048] Examples of indigo compounds include indigo.

[0049] Examples of metal complexes include iron(III)-complexed trisodium 5-nitroso-6-oxidonaphthalene-2-sulfonate (also known as "Naphthol Green B").

[0050] 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”.

[0051] Examples of coumarin compounds include 7-amino-4-(trifluoromethyl)coumarin, 7-amino-4-methylcoumarin, 3-(2-N-methylbenzimidazolyl)-7-N,N-diethylaminocoumarin (also known as "Coumarin 30"), 2,3,6,7-tetrahydro-10-(3-pyridyl)-1H,5H,11H-[1]benzopyrano[6,7,8-11]quinolizin-11-one (also known as "Coumarin 510"), 3-(2-Benzothiazolyl)-7-(diethylamino)coumarin (also known as "Coumarin 6").

[0052] Examples of compounds comprising a cyanine group include indocyanine green, 5,5'-dichloro-11-diphenylamino-3,3'-diethyl-10,12-ethylenethiatricarbocyanine perchlorate (also known as IR140).

[0053] Examples of compounds comprising a phthalocyanine group include iron (III) phthalocyanine chloride, iron (III) phthalocyanine-4,4',4",4'"-tetrasulfonic acid, cobalt (II) 1,2,3,4,8,9,10,11,15,16,17,18,22,23,24,25-hexadecafluoro-29H,31H-phthalocyanine, copper (II) phthalocyanine, compounds comprising a hydrated oxygen monosodium salt.

[0054] The invention also relates to a method for detecting the presence of at least one chemical compound on a surface, the method comprising at least the following successive steps: a) a step of spraying the composition contained in the colorimetric detection device as defined above, onto the surface likely to comprise the chemical compound to be detected; b) a step of deducing the presence of the chemical compound on the surface, based on a possible colorimetric change.

[0055] According to a first particular embodiment, the spraying step can be implemented once the surface on which it is desired to detect the presence of at least one chemical compound has been brought into contact with a medium, preferably liquid or solid, comprising this chemical compound to be detected. In other words, the detection method of the invention can comprise, prior to step a), a step of bringing the surface into contact with a medium likely to comprise the chemical compound.

[0056] In other words, this first embodiment makes it possible to detect, a posteriori, the chemical compound deposited on the surface.

[0057] According to this first embodiment, it is advantageous to use the composition contained in the spray which comprises an aqueous dispersing phase. Indeed, once the deduction step has been carried out, it will be easy to clean with water the surface on which the composition has been sprayed, allowing reuse of this surface.

[0058] According to a second particular embodiment, the spraying step can be implemented before the surface on which it is desired to detect the presence of at least one chemical compound is brought into contact with a medium, preferably liquid or solid, comprising this chemical compound to be detected. In other words, the detection method of the invention can comprise, between steps a) and b), a step of bringing the surface into contact with a medium likely to comprise the chemical compound.

[0059] In other words, this second embodiment allows the chemical compound deposited on the surface to be detected in real time.

[0060] According to this second embodiment, it is preferred that the composition contained in the device is water-resistant. Also, it is advantageous to use the composition contained in the spray which comprises an organic dispersing phase. Indeed, once the deduction step has been carried out, it will be easy to clean the surface on which the composition has been sprayed by rubbing and / or using n-decane, which allows this surface to be reused. Furthermore, the surface on which the composition contained in the spray is sprayed can be any surface likely to have been in contact or to be in contact with a medium comprising the chemical compound to be detected. Such a surface can therefore be a complex or flexible surface, such as on the surface of a tire, a garment or even a shoe.

[0061] It is understood that the colorimetric detection device used in the above-mentioned method must be capable of detecting the chemical compound whose presence or absence is to be determined.

[0062] The deduction step can be easily done with the naked eye, upon observing a change in color of the surface onto which the composition contained in the device has been sprayed. However, the use of optical or optoelectronic devices can also be considered, if necessary, during this step.

[0063] According to the invention, the chemical compounds capable of being detected by the method of the invention may be toxic compounds, such as toxic war compounds or toxic industrial compounds.

[0064] More specifically, toxic warfare compounds can be G-series organophosphorus compounds (such as Sarin or Tabun), V-series organophosphorus compounds (such as compound VX), other organophosphorus compounds such as compounds A-232, A-230, A-234 and A-242, vesicant compounds (such as sulfur mustard, nitrogen mustard and Lewisite) or arsenic compounds (such as Clark 1 and Clark 2).

[0065] Other characteristics and advantages of the invention will emerge from the additional description which follows.

[0066] It goes without saying that this additional description is given only as an illustration of the subject of the invention and must in no case be interpreted as a limitation of this subject. DETAILED DESCRIPTION OF PARTICULAR EMBODIMENTS

[0067] 1. Impregnation of particles with a colored indicator

[0068] This example illustrates the preparation of different particles impregnated with colored indicators according to the following operating protocol:

[0069] 1°) weighing the powder in a flask;

[0070] 2°) weighing the quantity of colored indicator required (0.1% or 0.5% by mass of colored indicator relative to the mass of powder) in a pillbox;

[0071] 3°) addition of a solvent allowing the solubilization of the colored indicator in the pillbox and so as to have a concentration of approximately 30 mg / mL;

[0072] 4) pouring the colored indicator solution into the flask onto the powder and rinsing the pillbox several times and pouring the rinsing solvent into the flask;

[0073] 5°) depending on the appearance of the powder in the flask, add as much solvent as necessary to wet and suspend the powder;

[0074] 6) evaporation in three stages:

[0075] *rotation in the water bath (55°C) of the rotary evaporator for 10 minutes to homogenize the suspension in the flask and increase the temperature;

[0076] *slow pressure reduction to 400 mbar to slowly distill the solvent;

[0077] *when the powders begin to group together to form a ring that attaches to the wall of the flask, the pressure is released more quickly until completely dry.

[0078] The table below shows the two prepared impregnated powders, with details of the nature of the powder, the colored indicator, the proportion of colored indicator and the solvent.

[0079] Silica is a silica with an average particle size of 2-25 pm and is supplied by Aldrich under the product number 288500-1KG. Polyethylene is a polyethylene with an average particle size of 30 pm and is supplied by Mitsui Chemicals under the product number MIPELON XM-220.

[0080] 2. Colored indicators encapsulated in particles made of a copolymeric material

[0081] 2.1 Encapsulation of bromocresol green in MMA / TMPTA copolymeric particles

[0082] The encapsulation of bromocresol green by copolymerization of methyl methacrylate (denoted MMA) and trimethylolpropane triacrylate (denoted TMPTA) is prepared according to the following protocol:

[0083] 1°) 5 mg of ground bromocresol green and 50 mg of Irgacure™ 819 photoinitiator (supplied by BASF with the commercial reference 56415892) are weighed, then suspended in 20 mL of cyclohexane in a 30 mL glass bottle and passed through ultrasound;

[0084] 2°) the suspension is placed under magnetic stirring in a UV tank (supplied by Hônle, under the reference UVA-cubelOO; 365 nm; ~4 mW / cm 2 ) ;

[0085] 3°) a solution comprising 0.2 mL of MMA and 0.8 mL of TMPTA (mass proportion MMA / TMPTA 20 / 80) is introduced into the suspension using a syringe, with stirring;

[0086] 4°) the suspension obtained at the end of point 3°) is irradiated under UV for 4 minutes; it then changes from a transparent appearance to a milky appearance.

[0087] 5°) cyclohexane is then added to remove the residual photoinitiator. The suspension is centrifuged at 10,000 rpm for 5 minutes, then the cyclohexane is removed and replaced with ethanol. The suspension is centrifuged again at 10,000 rpm for 5 minutes to remove the residual unencapsulated bromocresol green; then,

[0088] 6°) the particles are recovered by filtration on a pleated filter, rinsed with water and dried at room temperature. 2.2 Encapsulation of Disperse Black 9 in copolymeric particles of

[0089] The encapsulation of Disperse Black 9 by copolymerization of MMA and TMPTA is prepared according to the same protocol described in point 2.1 above.

[0090] 2.3 Encapsulation of 4-nitrobenzaldehyde(2,4-dinitrophenyl)hydrazine in

[0091] The encapsulation of 4-nitrobenzaldehyde(2,4-dinitrophenyl)hydrazine by copolymerization of MMA and TMPTA is prepared according to the following protocol:

[0092] 1°) 0.2 mL of MMA and 0.8 mL of TMPTA (mass proportion MMA / TMPTA

[0093] 20 / 80) are placed in a pill box;

[0094] 2°) 50 mg of Irgacure™ 819 are added, then the mixture is placed under magnetic stirring in a UV tank (of the same reference as that used in point 2.1 above);

[0095] 3°) 5 mg of hydrazine in cyclohexane are added to the UV tank;

[0096] 4) the suspension is irradiated under UV for 4 minutes; it then changes from a transparent appearance to a milky appearance;

[0097] 5°) cyclohexane is added to remove the residual photoinitiator. The suspension is centrifuged at 10000 rpm for 5 minutes. The cyclohexane is removed and replaced with ethanol. The suspension is centrifuged again at 10000 rpm for 5 minutes, to remove the residual unencapsulated hydrazine; then,

[0098] 6°) the particles are recovered by filtration on a pleated filter, then placed in 10 mL of cyclohexane.

[0099] 2.4 Encapsulation of bromocresol purple, in the form of sodium salt. in

[0100] The encapsulation of bromocresol purple by copolymerization of MMA and TMPTA is prepared according to the following protocol:

[0101] 1°) 10 mg of bromocresol purple and 113 mg of Irgacure™ 819 are weighed and solubilized, if necessary using ultrasound, in 0.4 mL of MMA and in 1.6 mL of TMPTA (MMA / TMPTA mass proportion 22 / 78);

[0102] 2°) the above mixture is then introduced by pipette into 20 mL of cyclohexane; 3°) the solution obtained in point 2°) is mixed manually until a homogeneous mixture is obtained;

[0103] 4) the solution is irradiated under UV for 2 minutes; it then changes from a transparent yellow appearance to a milky yellow appearance;

[0104] 5°) the solution is centrifuged at 10,000 rpm for 5 minutes, then the cyclohexane is removed and replaced with ethanol. The solution is centrifuged again at 10,000 rpm for 5 minutes to rinse the particles, remove the photoinitiator and the residual unencapsulated bromocresol purple; then,

[0105] 6) the particles are recovered by filtration in a pleated filter, rinsed with water and dried at 80°C.

[0106] 3. Solvent resistance and simulant exposure of MMA / TMPTA particles encapsulating bromocresol purple

[0107] The particles obtained at the end of point 2.4 are placed in contact with ethanol for approximately 5 minutes.

[0108] As a result, after this contact, the particles did not dissolve. This confirms that they are perfectly resistant to ethanol, which limits the migration of the colored indicator into the solvent.

[0109] A drop of sodium hydroxide - simulating a toxic compound to be detected - diluted in 1-butanol, is then placed on the surface of these particles. A change in color is then observed: the particles go from yellow to blue. This therefore confirms that the simulant reaches the interior of the particles and that these allow the detection of the presence of a chemical compound.

[0110] 4. Use of a spray comprising particles impregnated with a colored indicator and / or particles encapsulating a colored indicator, against simulants

[0111] 4.1 Spraying a composition comprising an organic dispersant phase and one or more colored indicators onto contaminated surfaces after exposure to DPCP and soda

[0112] 4.1.1. Composition comprising a single colored indicator First, drops of diphenyl chlorophosphate (more simply noted DPCP), simulating a toxic substance to be detected, were deposited in several places on the following supports:

[0113] - protective glasses (of the type used in chemistry laboratories);

[0114] - nitrile gloves; and

[0115] - absorbent paper.

[0116] At the same time, the silica particles impregnated with Disperse Black 9 (obtained in point 1 above) are suspended in 28.5 g of cyclohexane.

[0117] The suspension is then introduced into a mechanical spray and is sprayed onto the various supports contaminated by DPCP.

[0118] We then observe:

[0119] - on the one hand, the deposition of a yellow layer on these supports, indicating good adhesion of the particles; and on the other hand,

[0120] - purple stains in the contaminated areas, confirming that Disperse Black 9 has reacted to the presence of DPCP.

[0121] 4.1.2. Composition comprising two different colored indicators

[0122] Drops of DPCP and sodium hydroxide diluted in 1-butanol were placed in several places on supports of the same type as those used in point 4.1.1.

[0123] The following protocol is then implemented:

[0124] 1°) 17.59 g of the suspension of Disperse Black 9 prepared previously (in point 4.1.1) in cyclohexane is poured into a 200 mL glass bottle;

[0125] 2) the polyethylene particles impregnated with bromocresol purple (obtained in point 1) are suspended in 12.36 g of cyclohexane;

[0126] 3°) 4.21 g of the bromocresol purple suspension are added to the 200 mL bottle, with 12.65 g of cyclohexane; the mixture is then introduced into a mechanical trigger spray and then sprayed onto the various contaminated surfaces.

[0127] We then observe: on the one hand, the deposition of a yellow layer on these supports, indicating good adhesion of the particles; and on the other hand, purple and blue stains at the locations having been contaminated respectively by DPCP and soda, confirming that the two colored indicators have reacted well to the presence of these simulants.

[0128] 4.2 Spraying a composition comprising an organic dispersant phase and several colored indicators onto a surface prior to exposure to DPCP and sodium hydroxide

[0129] The spray is applied here in the form of a patch on a plastic film (supplied by Pavo PP, with the commercial reference 8007882).

[0130] To do this:

[0131] 1°) 21 mg of polystyrene-block-poly(ethylene-ran-butylene)-block-polystyrene (denoted PSPEPB) are dissolved in 20 g of cyclohexane; PSPEPB has a mass average molar mass Mw ~89,000 and is supplied by Sigma Aldrich with the commercial reference 200565-250G;

[0132] 2°) 0.4 g of each of the particles encapsulating bromocresol green, Disperse Black 9 and 4-nitrobenzaldehyde(2,4-dinitrophenyl)hydrazine (respectively obtained in points 2.1, 2.2 and 2.3) are then added; then

[0133] 3°) 16 glass beads with a diameter of 10 mm are added and the mixture is stirred for 5 minutes with a vortex.

[0134] A homogeneous suspension is then obtained, introduced into a spray and then sprayed twice onto the plastic film, in the form of a patch. A drying time at room temperature is observed after each spray.

[0135] The plastic film is then exposed to DPCP and soda.

[0136] Vivid color shifts are observed at the patch level.

[0137] 4.3 Spraying a composition which comprises an aqueous dispersant phase and a colored indicator, onto a contaminated surface after exposure to soda.

[0138] A suspension is prepared by implementing the following steps:

[0139] 1°) 0.96 g of Glucopon are dissolved in 20 g of water;

[0140] 2°) the pH is adjusted to a value equal to 4, by adding 1M phosphoric acid; 3°) 400 mg of the particles encapsulating bromocresol green (obtained in point 2.1) are added;

[0141] 4) 16 glass beads with a diameter of 9 mm are added and the mixture is vortexed for 10 minutes;

[0142] 5°) 4 mL of THF are added to break the foam formed; a suspension of a flaky solid is obtained and is introduced into a mechanical trigger spray.

[0143] The suspension is then sprayed onto a plastic film (of the same reference as that used in point 4.2), which includes a drop of soda diluted in 1-butanol.

[0144] A colorimetric shift towards light blue is observed when the suspension and the soda come into contact.

[0145] 4.4 Spraying a composition which comprises an aqueous dispersant phase and a colored indicator, onto a surface before exposure to soda

[0146] The suspension obtained in point 4.3 is sprayed twice onto a plastic film (of the same reference as those used above), in the form of a patch. A drying time, at room temperature, is observed after each spraying.

[0147] The plastic film is then exposed to soda diluted in 1-butanol.

[0148] A sharp color shift is observed at the patch level.

[0149] 5. Use of a spray comprising particles encapsulating a colored indicator, against toxic war compounds

[0150] Three different sprays are used in this part:

[0151] - the first spray comprises the particles encapsulating Disperse Black 9, obtained in point 2.2;

[0152] - the second spray comprises the particles encapsulating 4-nitrobenzaldehyde(2,4-dinitrophenyl)hydrazine, obtained in point 2.3; and the third spray comprises these two types of particles.

[0153] Each of these sprays are obtained by implementing the following steps:

[0154] 1°) 21 mg of PSPEPB are dissolved in 20 g of cyclohexane; the PSPEPB has a mass average molar mass Mw ~89,000 and is supplied by Sigma Aldrich with the commercial reference 200565-250G; 2°) 0.4 g of the particles are then added; then

[0155] 3°) 16 glass beads with a diameter of 10 mm are added and the mixture is stirred

[0156] 5 minutes in the vortex.

[0157] Then, each spray is sprayed twice, in the form of a patch, onto a separate plastic film. A drying time at room temperature is observed after each spray.

[0158] The plastic films are then exposed to the following 4 toxic war compounds: A-230

[0159] Sulfur mustard (HD) Lewisite (LI)

[0160] Sarin is a G-series organophosphorus compound, and sulfur mustard and Lewisite are both blister compounds.

[0161] To do this, 1.2 pL of each of these toxic compounds are deposited on the plastic films via a multi-channel electronic pipette.

[0162] The media are scanned before exposure to toxic compounds, then after 5 minutes and after 1 hour.

[0163] It follows that:

[0164] - the first spray can detect Sarin, Sulphur Yperite and Lewisite;

[0165] - the second spray allows the detection of compound A-230; and

[0166] - the third spray can detect Sarin, compound A-230, sulfur mustard gas and Lewisite. REFERENCES CITED

[0167] [1] Shrishty Bakshi et al., Advanced Functional Materials, 2022,32, 2103496

Claims

Claims 1. Colorimetric detection device for the detection of at least one chemical compound, in the form of a spray and containing a composition which comprises a dispersing phase in which is dispersed at least one colored indicator capable of changing in the presence of the chemical compound, characterized in that the colored indicator is present in the dispersing phase in the form of a plurality of solid particles which are impregnated with the colored indicator or in which the colored indicator is encapsulated.

2. Device according to claim 1, in which each solid particle is impregnated with only one colored indicator or encapsulates only one colored indicator when several different colored indicators are dispersed in the dispersing phase.

3. Device according to claim 1 or 2, in which the solid particles are made of an inorganic material chosen from silica, alumina, zinc oxide, titanium oxide or zeolite, preferably silica.

4. Device according to claim 1 or 2, in which the solid particles are made of an organic material, preferably a polymeric or copolymeric material comprising at least one monomer chosen from ethylene, methyl (meth)acrylate, and trimethylolpropane triacrylate and, better still, chosen from methyl (meth)acrylate and trimethylolpropane triacrylate.

5. Device according to any one of claims 1 to 4, in which the solid particles have a number average size of between 0.1 pm and 100 pm, preferably between 5 pm and 50 pm.

6. Device according to any one of claims 1 to 5, in which the colored indicator is chosen from anthraquinone compounds, 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.

7. Method for detecting the presence of at least one chemical compound on a surface, comprising at least the following successive steps: a) a step of spraying the composition contained in the colorimetric detection device according to claims 1 to 6, onto the surface; b) a step of deducing the presence of the chemical compound on the surface, based on a possible colorimetric change.

8. Detection method according to claim 7, which comprises, either prior to step a) or between steps a) and b), a step of bringing the surface into contact with a medium capable of comprising the chemical compound.

9. Detection method according to claim 7 or claim 8, in which the chemical compound is chosen from toxic war compounds and toxic industrial compounds.

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