Analytical method for detecting peroxide-, halogen oxoanion-, nitrate-, nitramine- and nitrotoluene-based explosives

Abstract

To provide an analytical method for detecting peroxide- oxyhalide anion-, and nitrogen-based explosives, with high sensitivity and without or with only one step of pre-treatment of a sample prior to a color reaction that can be detected visually, preferably without spectrophotometric detection.SOLUTION: The present invention provides an analytical method, preferably a one-step method, for detecting in a sample peroxide-based explosives, nitrate-based explosives and / or nitramine-based explosives, the method comprising contacting a sample suspected of containing a peroxide-based compound, especially a peroxide-based explosive, a nitramine, nitrate ester or a nitrate salt, especially a nitrate-based explosive and / or a nitramine-based explosive, with a composition comprising a Ni-porphyrin, an acid and preferably an acid-stable solvent.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to analytical methods for detecting several classes of compounds, preferably explosives, in particular peroxides, oxyhalide anions and nitrogen compounds. These compounds include, in particular: 1. peroxide compounds, in particular peroxide explosives, such as triacetone triperoxide (TATP), diacetone diperoxide (DADP), methyl ethyl ketone peroxide (MEKP), hexamethylene triperoxide diamine (HMTD); 2. oxyhalide anions, in particular chlorates (e.g. sodium chlorate (NaClO3), potassium chlorate (KClO3)) or bromates, such as sodium bromate (NaBrO3); 3. inorganic nitrates, such as potassium nitrate (KNO3), ammonium nitrate (NH4NO3), urea nitrate (NH2COHNH2 + NO3 - ), 4. organic nitrates (nitric acid esters), such as nitroglycerin (NG), ethylene glycol dinitrate (EGDN), pentaerythritol tetranitrate (PETN), 5. nitroamines, such as 1,3,5-trinitro-1,3,5-triazinane (hexogen, RDX), 1,3,5,7-tetranitro-1,3,5,7-tetrazoctane (octogen, HMX), 2,4,6-trinitrophenylmethylnitramine (tetryl), and / or nitrourea (NH2CONHNO2), and 6. nitrotoluenes, such as 2,4-dinitrotoluene (DNT) or 2,4,6-trinitrotoluene (TNT). The analytical method of the present invention has the advantage of being highly sensitive, does not require sample preparation, and detects most of the relevant classes of explosive compounds with the same reagents by a simple chemical colorimetric test in one or two steps. [Background technology]

[0002] Detection kits may contain several reagents or host compounds that cover and identify a wide range of explosive classes. Chemical methods usually require sample preparation. Several methods exist for the chemical detection of nitrogen-based explosives. However, there are only a limited number of colorimetric detection methods for peroxide-based explosives.

[0003] WO 99 / 43846 (Ehud Keinan and Harel Itzhaky) describes a colorimetric method and kit for detecting peroxide-based explosives (cyclic peroxides), such as triacetone peroxide (TATP), diacetone peroxide (DADP), and hexamethylene triperoxide diamine (HMTD). The detection of peroxides is based on a two-step process. The first step requires dissolving the suspected material in an organic solvent and hydrolyzing the cyclic peroxides to acetone and hydrogen peroxide with a strong acid. In the second step, the acidic solution is neutralized with a buffer and hydrogen peroxide is detected by the color change of a redox-active dye that is oxidized by hydrogen peroxide and a peroxidase enzyme. The patent includes a kit for the practical application of the invention, which includes a solution of an organic solvent, a strong acid, a buffer, a peroxidase enzyme, and a redox-active dye. The reason for this rather complicated detection procedure is due to the fact that strong acids are required for the cleavage of cyclic peroxides (explosives), but the actual colorimetric detection can only be carried out at neutral pH. Therefore, neutralization of the solution is necessary as an intermediate step.

[0004] Lin and Suslick, J. Am. Chem. Soc. pp. 15519-15521 (2010), on the colorimetric detection of TATP, describe a method in which a gas sample is acid hydrolyzed by flowing through a bed of the acid form of sulfonated highly cross-linked polystyrene ion exchange resin Amberlyst 15, followed by contacting the reaction products with a series of redox dyes. Since the acid is immobilized on a porous solid resin, the cleavage of the cyclic peroxide occurs in the gas phase within the resin, avoiding a separate neutralization step. However, a drawback of this procedure is the fact that only volatile explosives (TATP and DADP) can be detected. Furthermore, in order to generate sufficient vapor pressure for detection, TATP and DADP need to be contained in a container or at least in a place where air exchange is minimal. Hexamethylene triperoxide diamine (HMTD), which has a higher sublimation point and lower vapor pressure compared to TATP and DADP, cannot be detected. An advantage of this method is the fact that TATP can be differentiated from other oxidants such as hydrogen peroxide and hydroperoxides by exposing the steam after solid acid hydrolysis to a series of redox active dyes with different reactivities.

[0005] Amisar in WO 2005 / 089058 A2 described a method for detecting chlorate, bromate, and / or organic peroxides. The detection kit includes two containers containing an organic solvent, a strong acid, an aromatic amine, and a transition metal ion.

[0006] In a follow-up patent, WO 2010 / 086834, Amisar describes a sequential procedure involving several steps and several reagents to detect 1. perchlorates, 2. nitroaromatics, 3. nitroamines, nitroesters, chlorates and bromates, 4. peroxides, 5. nitrates in the same sample.

[0007] Regarding the detection of TATP or HMTD, Schulte-Ladbeck et al., Analyst pp. 1152-1154 (2002), describe the addition of catalase to a liquid test sample to remove free hydrogen peroxide, followed by extraction with acetonitrile to remove the catalyst, and then irradiating the sample with UV light to decompose the peroxide compounds in an enzyme-catalyzed reaction, with the hydrogen peroxide produced by the decomposition reaction being detected colorimetrically.

[0008] US Patent No. 7,799,573 B2, Detection of Explosives and Other Species, describes the detection of peroxide-based explosives by acid or light induced decomposition to hydrogen peroxide and subsequent detection of the hydrogen peroxide by reaction with oxalate esters and detection of their chemiluminescence.

[0009] M. K. Chahal, M. Sankar, Dalton Trans. 2016, 45, 16404-16412, describe the synthesis of Ni-porphyrin (Ni-tetra(4-hydroxyphenyl)porphyrin).

[0010] M. K. Chahal and M. Sankar, Dalton Trans. 2017, 46, 11669-11678, report a novel method for the detection of cyanide (CN) using Ni-porphyrin (Ni-tetra(4-hydroxyphenyl)porphyrin) as a sensor compound. - ), fluoride (F - ), and the detection of picric acid.

[0011] Unrelated to their use in detecting explosives, Cong et al., Inorganic Chemistry 14361-14376 (2019) describe perhalogenated Ni-porphyrin compounds.

[0012] Regardless of their use in explosive detection, B. Du, A. Langlois, D. Fortin, C. Stern, P.D. Harvey, J. Clust. Sci. 2012, 23, 737-751, show that substitution with acid groups increases the pKa 4.2 is described.

[0013] Independent of its use in explosives detection, C. Matos, C. Ribeiro, L. R. Gomes, Med. Chem. Res. 2015, 24, 3885-3891, describe the interaction of an acid-substituted porphyrin (meso-tetra(4-carboxyphenyl)porphine) with model membranes.

[0014] Optical detection methods for nitroaromatics, nitroamines, and nitrate esters are reviewed in "Optical explosives detection: from color changes to fluorescence turn-on", Germain, ME; Knapp, MJ Chem. Soc. Rev. 2009, 38, 2543. Methods for detecting nitrogen-based explosives such as inorganic nitrates, organic nitrates, and nitroamines are described in Method and kit for detecting explosives, Margalit, Y. Eur. Pat. Appl. (1994), European Patent No. 586125 A2, and U.S. Patent No. 5,480,612.

[0015] WO 2008 / 130376 A2 (Determination of Explosives Including RDX) shows a method for detecting nitroamines, such as RDX and PETN, using dyes such as 9,10-didehydroacridine or 9,10-didehydroanthracene derivatives which, upon irradiation with UV light, act as hydride donors and reduce the nitramines, thereby converting them to fully conjugated acridine or anthracene derivatives. Detection is performed by observing the change in absorption or emission.

[0016] WO 2013 / 022494 (Detection of analytes, including nitro-containing analytes) describes a variation of WO 2008 / 130376 A2 in which the decomposition products after irradiation with UV light react by electrophilic aromatization of electron-rich aromatic compounds. Detection is based on an optical signal, which may be a change in absorption or emission.

[0017] AD Jarczewski, P. Pruszynski, KT Leffek, Can. J. Chem. 1979, 57, 669-672; SAH Amas, HJ Yallop, Analyst 1966, 91, 336-337, describe that nitrotoluenes, such as 2,4-dinitrotoluene (DNT) or 2,4,6-trinitrotoluene (TNT), immediately give a blue (DNT) or purple (TNT) color upon treatment with organic superbases.

[0018] None of these articles or patents describe a comprehensive colorimetric method (detection based on optical signals) for the detection of peroxide explosives, oxyhalide anions, nitramines, nitrate esters and / or nitrates with the same reagent. None of the published methods report a colorimetric method for the detection of peroxide explosives (cyclic peroxides) in one step without a separate activation step using acid, base or ultraviolet light. [Prior art documents] [Patent documents]

[0019] [Patent Document 1] WO 99 / 43846 [Patent Document 2] International Publication No. 2005 / 089058 A2 [Patent Document 3] International Publication No. 2010 / 086834 [Patent Document 4] US Patent No. 7799573 B2 [Patent Document 5] European Patent No. 586125 A2 [Patent Document 6] U.S. Patent No. 5,480,612 [Patent Document 7] International Publication No. 2008 / 130376 A2 [Patent Document 8] International Publication No. 2013 / 022494 [Non-Patent Document]

[0020] [Non-Patent Document 1] Lin and Suslick, J. Am. Chem. Soc. pp. 15519 - 15521 (2010) [Non-Patent Document 2] Schulte-Ladbeck et al., Analyst pp. 1152 - 1154 (2002) [Non-Patent Document 3] M. K. Chahal, M. Sankar, Dalton Trans. 2016, 45, pp. 16404 - 16412 [Non-Patent Document 4] M. K. Chahal, M. Sankar, Dalton Trans. 2017, 46, pp. 11669 - 11678 [Non-Patent Document 5] Cong et al., Inorganic Chemistry pp. 14361 - 14376 (2019) [Non-Patent Document 6] B. Du, A. Langlois, D. Fortin, C. Stern, P. D. Harvey, J. Clust. Sci. 2012, 23, pp. 737 - 751 [Non-Patent Document 7] C. Matos, C. Ribeiro, L. R. Gomes, Med. Chem. Res. 2015, 24, pp. 3885 - 3891 [Non-Patent Document 8] "Optical explosives detection: from color changes to fluorescence turn-on", Germain, M. E.; Knapp, M. J. Chem. Soc. Rev. 2009, 38, 2543 [Non-Patent Document 9] Method and kit for detecting explosives, Margalit, Y. Eur. Pat. Appl. (1994) [Non-Patent Document 10] A. D. Jarczewski, P. Pruszynski, K. T. Leffek, Can. J. Chem. 1979, 57, 669 - 672 [Non-Patent Document 11] S.A.H. Amas, H. J. Yallop, Analyst 1966, 91, 336 - 337 [Non-Patent Document 12] M. M. Catalano, M. J.Crossley, M. M. Harding, L. G. King, Control of Reactivity at the Porphyrin Periphery by Metal Ion Co-ordination: a General Method for Specific Nitration at the β-Pyrrolic Position of 5,10,15,20-Tetraarylporphyrins. Chem. Commun. 1984, 1535 - 1536 [Non-Patent Document 13] V. Montanari, K. Kumar, Eur. J. Org. Chem. 2006, 4, 874 - 877 [Non-Patent Document 14] J. Ignatowska, O. Shyshkov, T. Zipplies, K. Hintzer, G.-V. Roschenthaler, J. Fluor. Chem. 2012, 141, 35 - 40 [Non-Patent Document 15] L. M., Jin, Z. Zeng, C.-C. Guo, Q.-Y. Chen, J. Org. Chem. 2003, 68, 3912 - 3917 [Non - Patent Document 16] Y. Zhao, J. Hu, Angew. Chem. Int. Ed. 2012, 51, 1033 - 1036 [Non - Patent Document 17] T. Hu, T. Liu, C. Hu, J. Lang, J. Porphyr. Phtalocyanines 2018, 22, 751 - 757 [Non - Patent Document 18] G. Bringmann, D. C. G. Gotz, T. A. M. Gulder, T. H. Gehrke, T. Bruhn, T. Kupfer, K. Radacki, H. Braunschweig, A. Heckmann, C. Lambert, J. Org. Chem. 2008, 130, 17812 - 17825 [Non - Patent Document 19] R. Labruere, P. Helissey, S. Debene - Finck, S. Giorgi - Renault, Lett. Org. Chem. 2012, 9, 568 - 571 [Non - Patent Document 20] G. Besong, D. Billen, I. Dager, P. Kocienski, E. Sliwinski, L. R. Tai, F. T. Boyle, Tetrahderon 2008, 64, 4700 - 4710 [Non - Patent Document 21] J. S. Lindsey, K. A. MacCrum, J. S. Tyhonas, Y. Y. Chuang, J. Org. Chem 1994, 59, 579 - 587 [Non - Patent Document 22] M. Dommaschk, F. Gutzeit, S. Boretius, R. Haag, R. Herges, Chem. Commun. 2014, 50, 12476 - 12478 [Non - Patent Document 23] BJ Johnson et al. Sensors 2010, 10, pp. 2315-2331 Summary of the Invention [Problem to be solved by the invention]

[0021] It is an object of the present invention to provide an analytical method for the sensitive detection of peroxide-, oxyhalide anion-, and nitrogen-based explosives, preferably without spectrophotometric detection and without or with only one sample pretreatment step prior to the visually detectable color reaction. The analytical method can be preferably performed in a short time, for example within 60 seconds, 30 seconds, 20 seconds, or less, at ambient conditions. A further object is to provide an easy-to-use device containing the reactants for use in the analytical method. [Means for solving the problem]

[0022] The present invention achieves the object by the features of the claims, in particular by providing an analytical method, preferably a one-step process, optionally with a step of pre-treating the sample with an organic superbase, for detecting peroxide-based explosives, oxyhalide anion-based explosives, nitrate-based explosives and / or nitroamine-based explosives as analytes in a sample, which comprises contacting a sample suspected of containing peroxide-based compounds, in particular peroxide-based explosives, oxyhalide anion-based compounds, in particular oxyhalide-based explosives, nitrate esters or salts, in particular nitrate-based explosives, or nitroamine-based compounds, with a composition comprising or consisting of Ni-porphyrin, an acid and preferably an acid-stable solvent. This method does not include a separate step of hydrolyzing the sample suspected of containing peroxide-based explosives prior to contacting the sample with the composition containing Ni-porphyrin. For the detection of nitroamine-based explosives, a two-step procedure is required: first the sample is treated with an organic superbase and in a second step the sample is contacted with a composition containing Ni-porphyrin as described above. The pretreatment with organic superbase does not interfere with or prevent the detection of peroxides, oxyhalide anions, nitrate esters and nitrates. Thus, all of the above compounds can be detected by the two-step procedure, but for the detection of nitroamines, pretreatment with organic superbase is necessary. Furthermore, the present invention provides a composition comprising Ni-porphyrin, an acid and optionally an acid-stable solvent for use as an analytical device in this analytical method. The acid may be present in a mixture with the Ni-porphyrin, or alternatively or additionally, the acid may be bound to the Ni-porphyrin, for example, the acid may be a substituent of the Ni-porphyrin.

[0023] This analytical method and composition has the advantage that it allows for differentiation between explosives, since peroxide-based explosives and oxyhalide anions are signaled by Ni-porphyrins and ultimately produce a green color, while nitrate-based explosives and nitramine-based explosives are signaled by Ni-porphyrins and initially produce a green color and ultimately produce a brown color.

[0024] The present invention further provides a device for use in an analytical method, the device comprising a composition comprising or consisting of Ni-porphyrin, an acid and preferably an acid-stable solvent, and preferably a carrier, e.g. a porous carrier, which retains the Ni-porphyrin, the acid and the acid-stable solvent, and which carrier forms a support material for the liquid composition of the present invention, the carrier being e.g. a porous liquid-absorbent material and / or a swellable liquid-absorbent material which forms a gel, e.g. a membrane of an acid-stable material, e.g. a membrane of a synthetic polymer or cellulose.

[0025] The method and composition of the present invention has the advantage of detecting explosives in one step because the Ni-porphyrin is acid stable, the acid decomposes the peroxide explosive to produce hydroperoxides or hydrogen peroxide, and the nitroamines or nitrates decompose to produce nitronium ions and / or nitrogen dioxide, which react with the Ni-porphyrin to change color. Nitroamines (e.g., hexogens and octogens) react slowly under these conditions. Thus, in accordance with the present invention, the reaction mechanism: (-N(NO2)-CH2- + B → -N=CH- + BH + + NO2 - According to the method described above, the nitramine is first treated with an organic superbase (B) to remove the nitrite. After a few seconds, e.g., less than 10 seconds of reaction time, the formed nitrite (NO2 - ) by applying the above procedure.

[0026] The method was found to be extremely sensitive to peroxides, since it is catalytic in peroxides, e.g. one TATP molecule will convert approximately 60 Ni-porphyrin molecules to the corresponding cation, which results in a color change from red to green. Nitrogen-based explosives also accept two electrons per NO2- group. For example, nitroglycerin and hexogen are capable of oxidizing six equivalents of Ni-porphyrin. The high sensitivity is also due to the fact that Ni-porphyrin exhibits a very high molar extinction coefficient of its Soret band. Therefore, only small amounts of porphyrin need to be used in the present invention for visual detection of the color change.

[0027] In contrast to the prior art, which uses a separate activation of the explosives, for example by separate acid or base hydrolysis or UV irradiation, with subsequent detection by color reaction, the analytical method of the present invention detects the above-listed explosives in a reaction which simply requires contacting a sample suspected of containing a peroxide-, oxyhalide- or nitrogen-based explosive with a composition comprising or consisting of Ni-porphyrin, an acid and optionally an acid-stable solvent.

[0028] The invention will now be explained in more detail with reference to the following, by way of example. [Brief description of the drawings]

[0029] [Figure 1] FIG. 2 is a diagram showing a reaction mechanism according to the present invention. [Diagram 2]2 shows UV spectra of reaction products obtained by analytical methods. The UV spectrum shown in FIG. 2 is a superposition of Ni-tetrakis(trimethoxyphenyl)porphyrin and trifluoroacetic acid (TFA), the reaction product of this composition according to the invention with TATP after 2.3 minutes as shown, and the reaction product of this composition according to the invention with TATP after 12.5 minutes. The UV spectrum demonstrated that the Soret and Q bands characteristic of Ni-porphyrin are reduced in the presence of TATP, and a broad band of 550-700 nm, typical of porphyrin radical cations, is established. [Diagram 3] FIG. 1 is a diagram showing a test piece according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0030] In one embodiment, the acid may be a free acid present in a mixture with Ni-porphyrin and optional solvent, but the free acid is not covalently bound to Ni-porphyrin. The free acid, for example in the form of a liquid acid, may be one acid or a mixture of at least two acids. Furthermore, the free acid may be in the form of a matrix-bound acid, the matrix may be a carrier. The matrix-bound acid may be, for example, a strong acid cation exchanger. The acid is generally active in decomposing cyclic peroxides, nitroamines, nitrate esters, and / or nitrates, particularly peroxide-based explosives, nitrate-based explosives, or nitroamine-based explosives. The strong base used to activate the nitroamine is an organic superbase, either in pure form or as a solution in an inert solvent such as acetonitrile. The pK of the organic superbase is preferably 0.01 to 0.01. a is preferably 24 or more.

[0031] The Ni-porphyrin preferably has an electron donating substituent at at least one meso position which is an aryl group, e.g., an aromatic group containing at least one phenyl ring, which is optionally substituted with at least one methoxy group, or with a substituted amino group, or with a linear, branched or cyclic alkyl group, each having, e.g., 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, or 12 carbon atoms. The Ni-porphyrin may be unsubstituted at its meso positions, or it may be substituted at one, two, three, or all four of its meso positions with electron donating groups, which may be the same or independently different for each meso position.

[0032] In general, in all embodiments, the acid preferably has a pK of at most 1.2. a pK value less than 1.2, e.g., between -2.8 and 0.23 a For example, p-toluenesulfonic acid has a pK of -2.8. a value, and trichloroacetic acid has a pK of 0.7. a Generally preferred acids have a pK value in the range of -1.2 to 0.23. a It has pK a The value is preferably determined in water at 20° C. A pK of up to 1 a A value of 0.1 to 1.0 is preferred because it decomposes peroxide explosives having a cyclic structure, such as TATP, in 30 seconds or less at 20° C. To prevent decomposition of Ni-porphyrin, the pK a should preferably not be below -4 (e.g. triflic acid pK a -5.1).

[0033] In one embodiment, the acid is a compound that is mixed with the Ni-porphyrin, preferably in an acid-stable solvent. The acid may have a pK of, for example, from -1.2 to 1.2 or 0.23. a The acid may be a strong acid having a pK a 0.23), pentafluoropropionic acid (pK a0.5-1.2), heptafluorobutyric acid (pK a 1.2), or perfluoropentanoic acid (pK a 0.5 to 1.2), preferably perfluoropentanoic acid, or trifluoroacetic acid, and a mixture of at least two of these.

[0034] The acid-stable solvent is preferably a solvent that stabilizes cations and radical cations. The acid-stable solvent may be an organic halogenated solvent, such as methylene chloride, chloroform, 1,1-dichloroethane, 1,2,3-trichloropropane, 1,2,3-trichloropropane, 1,1,2,3-tetrachloropropane, 1,1,1,2,3-pentachloropropane, 1,1,2,3,3-pentachloropropane, a fluorinated C2- to C6-alcohol, preferably hexafluoroisopropanol (HFIP), or sulfolane, or a mixture of at least two of these.

[0035] In chlorinated solvents, the acid is preferably trifluoroacetic acid (TFA), pentafluoropropionic acid, heptafluorobutyric acid, or perfluoropentanoic acid. In chlorinated solvents, in fluorinated alcohols, such as HFIP, or in sulfolane, the acid may be toluenesulfonic acid. Preferentially, in some embodiments, a high boiling point solvent is combined with a high boiling point acid to prevent rapid evaporation.

[0036] In further embodiments, the acid may be a substituent of the Ni-porphyrin, for example bound to the porphyrin moiety, preferably bound to the β-position of at least one pyrrole ring of the Ni-porphyrin, and / or the acid may be a substituent of an aryl substituent at the meso-position of the Ni-porphyrin. The substituent acid is preferably bound to the Ni-porphyrin, for example to its pyrrole ring and / or to its aryl substituent, via an intermediate linker, which has a chain length of at least one atom, preferably at least two atoms, or at least four, or at least six atoms. The linker between the acid substituent and the pyrrole moiety of the Ni-porphyrin preferably has a chain length of at least two atoms, for example 2-18 atoms, for example 4-18 atoms, or 6-18 atoms, for example 16 or less, or 14 or less, or 12 or less atoms, for example 1, 2, 3, 4, 5, 6, 7, 8, or 9 atoms. The linker atoms are preferably C atoms, optionally mono- or dihalogenated, and / or O atoms. The linker between the acid substituent and the aryl substituent at the meso position of the Ni-porphyrin preferably has a chain length of at least one atom, for example at least two atoms, for example 2 to 18 atoms, for example 4 to 12 atoms, and these atoms are preferably C atoms, optionally mono- or dihalogenated, and / or O atoms. The linker chain atoms are preferably carbon atoms. The linker may be an optionally halogenated alkyl chain, for example a chain comprising or consisting of at least one halogenated methyl group, for example a -CF2- group or a -CCl2- group. As an alternative to a linker connecting the acid substituent and the aryl substituent, the acid substituent may be directly bonded to the aryl group. Ni-porphyrins having an aryl substituent at at least one of the meso positions and an acid substituent directly bonded to the aryl substituent have the advantage that they can be prepared by a simpler synthesis.

[0037] The acid may be, for example, a carboxyl group, a sulfidic acid group, such as a sulfinic acid group, or a sulfonic acid group. To achieve a pKa<1, the carboxyl group is preferably directly connected to at least one -CF2- group or a fluorinated alkyl group, which may form a linker or may be part of a linker, and the sulfonic acid group may be connected, for example, to either a -CH2- or -CF2- group.

[0038] In general, the composition comprising Ni-porphyrin and acid and optionally solvent can be held on, e.g. adsorbed on or contained in, a solid support, which may be, e.g., a porous material or a gel. The porous material may be, e.g., silica or zeolite or cellulose. The gel may be, e.g., an acid-stable polymer, such as polyvinyl alcohol (PVA) or polyvinylpyrrolidone (PVP). Preferentially, gels containing acid in the polymer backbone are used. These gels are commercially available as strong acid cation exchange resins, such as Amberlite® R-120 or Dowex® 50 WX-4.

[0039] The organic superbase should be a neutral base that is soluble in organic solvents and has a pK of 0.01 or lower in acetonitrile. a >24. These bases are from the amidine, guanidine, phosphazene (Schwesinger bases), guanidinophosphazene, or proazaphosphatran (Verkade base) families. An example of a suitable amidine is 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU, pK a 24.3). A guanide with sufficient base strength is, for example, 2-t-bu-1,1,3,3-tetramethylguanidine (pk a 24.3), 7-H-1,5,7-triazabicyclo[4.4.0]dec-5-ene (pK a 26.0), 7-methyl-1,5,7-triazabicyclo[4.4.0]dec-5-ene (pK a25.5), or 1,8-bis(tetramethylguanidino)naphthalene (pK a 25.1). The most effective are phosphazene bases (Schwesinger bases), such as t-bu-hexamethylphosphorimidotriamide (P1-t-Bu, pK a 26.9), or 1,1-(dimethylethyl)tris[tris(dimethylamino) phosphoranylidene]phosphorimidic triamide (P4-t-Bu, pK a 42.6). 1,1,3,3-Tetramethylguanidine (pK a 23.3) Nitroamines (hexogens or octogens) (pK a <24, see above). Aqueous solutions of NaOH or KOH are also not suitable due to the long reaction times even at high temperatures.

[0040] As an alternative to holding the composition on a carrier, the composition can be contacted with the sample in the form of droplets, for example by spraying a liquid composition containing Ni-porphyrin and contacting the composition on a solid carrier, preferably a white carrier, which may be, for example, the wall of a container suspected of containing the sample containing explosives, or a paper, plastic or glass surface placed in or near the sample. In this embodiment, the acid is preferably a substituent of the Ni-porphyrin, which has the advantage that Ni-porphyrin covalently bound to an acid is less irritating, less volatile and / or less corrosive than the free acid.

[0041] Test strips can be prepared by using a strong acid cation exchange resin impregnated with Ni-porphyrin dissolved in a halogenated solvent as a carrier containing free acid, which is the form of acid bound to the matrix. The test strips can be immersed in a headspace of TATP or EGDN, or in a small amount of a peroxide-based or nitrogen-based explosive, such as triacetone triperoxide (TATP), diacetone diperoxide (DADP), hexamethylene triperoxide diamine (HMDT), methyl ethyl ketone peroxide (MEKP), potassium chlorate (KClO3), potassium bromate (KBrO3), potassium nitrate (KNO3), ammonium nitrate (NH4NO3), urea nitrate (NH2COHNH2 + NO3 - ) 、 Direct contact with nitroglycerin (NG), ethylene glycol dinitrate (EGDN), pentaerythritol tetranitrate (PETN), hexogen (RDX), octogen (HMX), 2,4,6-trinitrophenylmethylnitramine (tetryl), or nitrourea (NH2CONHNO2) causes a color change from red to green. In the case of nitrogen-based explosives, a color change from green to brown is then observed. Explosive detection is also possible in mixtures such as black powder (KNO3 / sulfur / charcoal) or pyrotechnic compositions (e.g. KClO3 / Al-powder).

[0042] In another embodiment of the invention, an acid-stable porous polymer membrane, such as a polypropylene membrane, a PVC membrane filter, or a porous polyvinylidene fluoride, or cellulose, impregnated with Ni-porphyrin dissolved in a pure acid, such as trifluoroacetic acid, or preferentially in a high boiling acid, such as pentafluoropropionic acid, is used as the test strip.

[0043] In general, the test strip may comprise an inert base material, for example a plastic strip, to which a porous material or gel is bonded for accommodating Ni-porphyrin with bound acid groups or mixed with free acid. The test strip may be combined as a kit of parts with free acid and / or an acid-stable solvent in a container suitable for dispensing liquids, and optionally with a superbase, preferably in a separate container suitable for dispensing liquids. Instead of Ni-porphyrin contained in the test strip, as a kit of parts, Ni-porphyrin mixed with free acid or Ni-porphyrin with bound acid groups may be present in a liquid composition, preferably an acid-stable solvent, optionally in combination with a superbase in a separate container suitable for dispensing liquids. The kit of parts contains a compound and is suitable for carrying out the analytical method of the present invention.

[0044] Immersion of the test strip in a headspace of TATP or EGDN, or direct contact with traces of peroxides, oxyhalide salts, nitrates, nitrate esters, or nitramines produces a color change from red to green.

[0045] In another embodiment of the invention, acid-substituted Ni-porphyrin dissolved in a solvent is sprayed onto a surface suspected of being contaminated with explosives. A color change from red to green will indicate the presence of explosives. Alternatively, a wipe can be used to sample the surface and the wipe can be sprayed.

[0046] The Ni-porphyrin may comprise or consist of one of structures 1-3, with structure 1 showing an embodiment in which the Ni-porphyrin is substituted with an aryl substituent (Ar) at all four meso positions. Exemplary aryl substituents can be independently selected from phenyl or other aromatic rings (Ar), which are optionally further substituted with at least one electron donating group, as herein shown as a methoxy group, for example one methoxy group or three methoxy groups, and three methyl groups. Exemplary aryl groups (Ar) are phenyl, methoxyphenyl, trimethoxyphenyl, and trimethylphenyl. The aryl group may be bonded to the carbon at the meso position of the Ni-porphyrin by any of its carbon atoms. In embodiments of acids covalently bound to Ni-porphyrins, it is generally preferred that at least one, e.g., one, two, three, or all four, of the substituents at the meso positions of the Ni-porphyrin are substituted with at least one acid group, e.g., at least one acid group is covalently bound to at least one of the aryl groups at the meso positions of the Ni-porphyrin.

[0047] [ka]

[0048] Structure 2 shows an embodiment in which all four meso positions of the Ni-porphyrin are substituted with aryl groups (Ar).

[0049] In one embodiment, which is less preferred, the aryl substituent does not have an electron donating group. In this embodiment, where the aryl substituent does not have an electron donating group, the analytical method is slower to produce an indicated color and the method is less sensitive.

[0050] In some cases, but less preferably, for example, for strong acids, such as -SO3H, the acid is directly attached to the Ni-porphyrin, in particular directly to the aryl group of the Ni-porphyrin, i.e., without the use of an intermediate linker. Preferably, the acid is attached to the Ni-porphyrin by an intermediate linker, which may have a chain length of at least one atom, preferably at least two, at least three, at least four, at least five, or more preferably at least six, or at least seven atoms, for example, a chain length of 12 or less, or 10 or less, or 8 or less atoms, for example, a C-atom, which may be optionally mono- or di-halogenated, and / or an O-atom forming an ether bond. Generally, preferably, for acid groups which are -CO2H, the acid is attached by a linker having at least one -CF2- group directly adjacent to the acid group. Generally, preferably, the linker may comprise or consist of a methylene group, an ether bond, a difluoromethylene group, a dichloromethylene group, or a combination of at least two of these.

[0051] Structure 1 is suitable for embodiments in which the composition comprises a Ni-porphyrin, an acid as a compound mixed with the Ni-porphyrin, and optionally a solvent.

[0052] Structures 2 and 3 show embodiments in which an acid is a substituent of a Ni-porphyrin. In Structure 2, the acid (acid) is directly bonded (X n where n=0), or a chain length of 1 to 10 atoms (X nwhere n is 10 or less), are covalently linked by an intermediate linker (chain) having a chain length of at least 2 atoms, e.g., preferably C-atoms, which may contain or consist of methylene groups (-CH2-), and / or difluoromethylene groups (-CF2-), and / or dichloromethylene groups (-CCl2-), and / or ether bonds (-O-). By way of example, the acid substituents are shown as carboxyl groups (CO2H) or as sulfonic acid groups (SO3H). In the embodiment of FIG. 2, up to 8 positions may carry acid groups, e.g. 1, 2, 3, or 4 or more positions may carry acid groups, which positions are β-positions of the Ni-porphyrin.

[0053] As shown in Structure 3, at least one acid (acid) generally has at least one atom, for example, 10 or fewer atoms (X nThe aryl group may be covalently linked to the aryl group at the meso position by an intermediate linker having a chain length as shown herein (where n is from 1 to 10), e.g. a chain length of at least 2 atoms, e.g. 3 to 6 atoms, preferably C-atoms. With respect to the exemplary phenyl ring as electron donating aryl substituent (Ar), the acid may be directly bonded or linked to the aryl group by a linker at any position of the aryl group, e.g. depending on the number of acid or linker substituents, preferably at the ortho or para position of the phenyl group as the exemplary aryl substituent, at two meta positions, or at two meta and para positions. Also herein, the linker chain may contain or consist of O groups forming ether bonds, methylene groups (-CH2-), and / or difluoromethylene groups (-CF2-) and / or dichloromethylene groups (-CCl2-) and / or ether bonds (-O-). The porphyrin may have, for example, 1 to 8 acid groups. In general, the acid bound to the Ni-porphyrin preferably has a pKa between -1.2 and 0.23, for example the acid is -SO3H or -CO2H, preferably with at least one difluoromethylene group linker directly adjacent to the acid which is -CO2H or -SO3H.

[0054] The reaction mechanism is currently assumed to be as shown in Figure 1, where the reaction of Ni-porphyrin with peroxide (ROOR) is 2+ (Ni II ) is shown with only a portion of the porphyrin. For simplicity, the unpaired electron and the positive charge of the porphyrin radical cation are shown as localized on the pyrrole nitrogen rather than delocalized on the porphyrin π-system.

[0055] There, the color change is based on the one-electron oxidation of porphyrins. Each peroxide unit in the reaction accepts two electrons, so that one molecule of TATP or HMTD, which contains three peroxide units, oxidizes six porphyrin molecules. A further improvement in sensitivity is achieved by the use of RO ·The reaction requires a radical chain reaction initiated by and incorporating atmospheric oxygen as an oxidant. In the case of the detection of nitramines and nitrates, the oxidized species is either the protonated species or the nitronium ion expelled therefrom. Acid cleavage corresponds to the reverse process of the synthesis of nitramines and nitrates. The nitronium ion (NO2 + ) is thereby reduced to nitrogen dioxide (NO2), which in turn oxidizes one equivalent of red porphyrin to the green porphyrin radical cation, which is reduced to the nitrite anion (NO2 - ). Once the red porphyrin is consumed, nitrogen dioxide reacts with the green porphyrin radical cation by radical recombination to form brown β-nitrated porphyrin (see, e.g., MM Catalano, MJ Crossley, MM Harding, LG King, Control of Reactivity at the Porphyrin Periphery by Metal Ion Co-ordination: a General Method for Specific Nitration at the β-Pyrrolic Position of 5,10,15,20-Tetraarylporphyrins. Chem. Commun. 1984, pp. 1535-1536). This explains the color change caused by the method and device of the present invention, which produces a color change from red to green on contact with peroxide-based explosives, and a color change from red to green and finally to brown on contact with nitrate- or nitramine-based explosives that is characteristic only of nitrogen-based explosives and allows for the differentiation of peroxide-based explosives from nitrogen-based explosives (see Examples).

[0056] To distinguish hydrogen peroxide from cyclic peroxides such as TATP and HMTD, dichloroacetic acid (pK aA weak acid such as 1.3) can be employed, which is strong enough to activate hydrogen peroxide but cannot hydrolyze cyclic peroxides. To avoid false positives due to hydrogen peroxide in practical applications, two test strips are used, one with a strong acid to detect any peroxides and one with a weak acid to detect only hydrogen peroxide. Weak acids have pK values ​​of, for example, 1.2-2. a

[0043]

[0057] Optionally, the method may comprise contacting the sample with the composition, or the method may comprise an additional step of destroying free hydrogen peroxide from the sample before contacting the sample with the composition, in order to reduce or eliminate the effect of free hydrogen peroxide. In order to hydrolyze free hydrogen peroxide, the sample may be contacted with a reactant having the activity of decomposing free hydrogen peroxide before contacting the sample with the composition comprising Ni-porphyrin. Thus, the device may optionally comprise a flow path in which the composition comprising Ni-porphyrin is arranged to receive the sample, and upstream of the composition is arranged a reactant having the activity of decomposing free hydrogen peroxide. The reactant may be, for example, an inorganic catalyst, such as KMnO4 or MnO2. The reactant may be immobilized on a porous support, which may optionally span the cross section of the flow path.

[0058] The flow path may for example be provided by a wicking material, for example a porous material, and / or by a duct through which the sample can travel, for example by capillary action or by positive or negative pressure applied to the duct. EXAMPLES

[0059] Example 1 Detection of solid TATP from the headspace A plastic strip (90 x 5 mm) with a cellulose pad (5 x 5 mm) at one end is impregnated with Ni-tetrakis(3,4,5-trimethoxyphenyl)porphyrin by dropping 5 μL of a 1 mM solution of the porphyrin in toluene onto the cellulose pad, then removing the solvent by evaporation. The strip thus prepared is moistened with a drop of 5-10 μL of perfluoropentanoic acid. The addition of acid to the Ni-porphyrin compounds of the invention herein is also considered as activation of the Ni-porphyrin or stick. The activated stick is brought in close proximity of approximately 3 mm to a crystal of TATP present on an uncoated surface or to the headspace of TATP present in a glass vial. After 15 seconds, the red color of the bud turns green. Assuming a saturated vapor pressure in the headspace of the solid explosive and a volume of 3 mL of gas, 8 nmol of TATP can be detected.

[0060] Example 2 Detection of organic nitrates (e.g. PETN, EGDN, NG) and nitrates (e.g. NH4NO3, KNO3, NaNO3) from the headspace Trace amounts of these compounds, PETN, EGDN, NG, and nitrates (e.g., NH4NO3, KNO3, NaNO3), present separately on an uncoated surface or in a glass vial, are treated with a drop (5-10 μl) of perfluoropentanoic acid. After a few seconds, an activated plastic strip prepared as in Example 1 is brought in close proximity (approximately 3 mm) to one of the compounds present on the surface or into the headspace of the glass vial. The color of the pad changes from red to brown. Detection of nitrates according to the present invention is also obtained when nitrates are present in solution or in a dry mixture, such as those with sulfur and charcoal, such as black powder.

[0061] Example 3 Detection of nitroamines (e.g. hexogens, octogens, nitroureas) from the headspace Separately, a trace of solid nitramine on a surface or in a glass vial is wetted with a drop (5-10 μl) of a solution of an organic superbase (e.g., 20 vol.% P1-t-Bu dissolved in acetonitrile). A drop (5-10 μl) of perfluoropentanoic acid is then placed on the same spot. An activated test strip, prepared as in Example 1, is brought in close proximity (approximately 3 mm) to the suspension of one of the nitramine compounds in the organic superbase on the surface or into the headspace of the glass vial. The pad immediately changes color from red to brown.

[0062] Example 4 Detection of solid-state peroxides (e.g., HMTD, TATP), chlorates (e.g., KClO3, NaClO3), and bromates (e.g., KBrO3, NaBrO3) Activated test strips (prepared as in Example 1) are contacted separately with traces of solid HMDT, TATP, or chlorate by wiping the contaminated surface. The color of the test strip immediately changes from red to green at the spots where the pad comes into contact with the trace of solid explosive. These green spots spread and within about 30 seconds the pad turns green. 10 μl of a 12.65 μM solution of TATP dissolved in dichloromethane is dropped as a round spot onto the previously prepared test strip. After 1 minute the test strip turns light green. Using this method it is possible to detect 0.125 nmol (28 ng) of TATP.

[0063] FIG. 3 shows a plastic strip (new (red)) to the end of which is attached a cellulose pad impregnated with Ni-porphyrin according to the invention before contacting it with the compound to be detected, a plastic strip containing the same Ni-porphyrin after it has been activated by adding acid and contacted with peroxide (peroxide (green)), and a plastic strip containing the same Ni-porphyrin after it has been activated by adding acid and contacted with nitrate (nitrate (brown)).

[0064] Example 5 Detection of organic nitrates (e.g. PETN, EGDN, NG) and nitrates (e.g. NH4NO3, KNO3, NaNO3) in crystalline or neat form An activated test strip prepared as in Example 1 is contacted with a trace of each solid nitrate or organic nitrate (PETN is a solid, EDGN and NG are liquids) by wiping the contaminated surface. The color of the strip changes immediately from red to green in the spots where the pad comes into contact with the trace of solid explosive. These green spots turn brown and spread across the entire pad.

[0065] Example 6 Detection of nitroamines in the solid state (e.g. hexogens, octogens, nitroureas) Separately, a trace of solid nitramine is wetted with a drop (5-10 μl) of a solution of an organic superbase (e.g., P1-t-Bu) in acetonitrile (20 vol.% P1-t-Bu). An activated test strip (prepared as in Example 1) is contacted with the suspension. The color of the pad immediately changes from red to brown.

[0066] Comparative Example 1 Detection of nitrotoluenes (e.g. 2,4-dinitrotoluene, 2,4,6-trinitrotoluene) Separate traces of these explosives, such as 2,4-dinitrotoluene or 2,4,6-trinitrotoluene, are contacted with an organic superbase (e.g., a 20 vol.% solution of P1-t-Bu in acetonitrile). The solution immediately changes from colorless to deep purple (TNT) or deep blue (DNT). No activated test strips are required in this case.

[0067] Example 7 Detection of HMTD and TATP from solution For detection of HMTD and / or TATP in solution, 300 μL of Ni-tetrakis(3,4,5-trimethoxyphenyl)porphyrin (50 μM in CHCl) and 50 μL of trifluoroacetic acid (13 M) were transferred to a sample tube. After adding 10 μL of a 25.3 μM solution (respectively HMTD or TATP in CHCl), the solution turned green within minutes due to the formation of the π-radical cation of the porphyrin. It was calculated that this method could detect 0.18 nmol (40 ng) of TATP or (50 ng) of HMTD as a color change from red to green. Similarly, the detection limit for potassium perchlorate (KClO3) was determined to be 270 ng, and for ammonium nitrate (NH4NO3) it is 85 ng.

[0068] Example 8 Synthesis of structure 2, chain: CH2(CF2)6, acid group: CO2H 2,2,3,3,4,4,5,5,6,6,7,7-dodecafluorooctane-1,8-diol was prepared using tosyl chloride and triethylamine to give the monotosylated species 2,2,3,3,4,4,5,5,6,6,7,7-dodecafluoro-8-hydroxyoctyl 4-methylbenzenesulfonate according to the recipe by V. Montanari, K. Kumar, Eur. J. Org. Chem. 2006, 4, 874-877. Reaction with potassium iodide gave 2,2,3,3,4,4,5,5,6,6,7,7-dodecafluoro-8-iodooctan-1-ol (synthesized according to V. Montanari, K. Kumar, Eur. J. Org. Chem. 2006, 4, 874-877). Reaction with (2,2,6,6-tetramethylpiperidin-1-yl)oxyl (TEMPO), potassium bromide, and sodium hypochlorite gave 2,2,3,3,4,4,5,5,6,6,7,7-dodecafluoro-8-iodooctanoic acid (adapted from J. Ignatowska, O. Shyshkov, T. Zipplies, K. Hintzer, G.-V. Roschenthaler, J. Fluor. Chem. 2012, 141, 35-40), which was reacted with methanol in an acid-catalyzed esterification to give methyl 2,2,3,3,4,4,5,5,6,6,7,7-dodecafluoro-8-iodooctanoate. Subsequent reaction with Ni-porphyrin, sodium dithionite, and sodium bicarbonate gives the porphyrin substituted at the β-position with perfluorinated acids (adapted from L. M., Jin, Z. Zeng, C.-C. Guo, Q.-Y. Chen, J. Org. Chem. 2003, 68, 3912-3917).

[0069] Another method for attaching acids to porphyrins is the Suzuki-Miyaura coupling with porphyrins bearing pinacol esters or boronic acids in the beta position (based on Y. Zhao, J. Hu, Angew. Chem. Int. Ed. 2012, 51, 1033-1036). The porphyrin was obtained by bromination with N-bromosuccinimide (NBS) (according to T. Hu, T. Liu, C. Hu, J. Lang, J. Porphyr. Phtalocyanines 2018, 22, 751-757) and subsequent reaction with bis(pinacolato)diboron, potassium acetate, and [1,1'-bis(diphenylphosphino)ferrocene]palladium(II) dichloride (in a modified form of G. Bringmann, DCG Gotz, TAM Gulder, TH Gehrke, T. Bruhn, T. Kupfer, K. Radacki, H. Braunschweig, A. Heckmann, C. Lambert, J. Org. Chem. 2008, 130, 17812-17825). In the final step, the acid is obtained by base-catalyzed ester saponification. The reaction is shown diagrammatically below:

[0070] [ka]

[0071] Example 9 Synthesis of structure 3, chain: CH2(CF2)2, acid: CO2H Starting from 2,2,3,3-tetrafluorobutane-1,4-diol, the monotosylated species 2,2,3,3-tetrafluoro-4-hydroxybutyl 4-methylbenzenesulfonate was obtained by reaction with tosyl chloride and triethylamine (synthesized according to V. Montanari, K. Kumar, Eur. J. Org. Chem. 2006, 4, 874-877). This compound was converted to 2,2,3,3-tetrafluoro-4-iodobutan-1-ol by reaction with potassium iodide (adapted from V. Montanari, K. Kumar, Eur. J. Org. Chem. 2006, 4, 874-877). Reaction with (2,2,6,6-tetramethylpiperidin-1-yl)oxyl (TEMPO), potassium bromide, and sodium hypochlorite produced 2,2,3,3-tetrafluoro-4-iodobutanoic acid (according to J. Ignatowska, O. Shyshkov, T. Zipplies, K. Hintzer, G.-V. Roschenthaler, J. Fluor. Chem. 2012, 141, 35-40). The acid is converted to the methyl ester by acid catalysis in methanol.

[0072] Starting from 3,4,5-trimethoxybenzaldehyde, bromination with N-bromosuccinimide (NBS) gave 2-bromo-3,4,5-trimethoxybenzaldehyde (synthesized according to R. Labruere, P. Helissey, S. Debene-Finck, S. Giorgi-Renault, Lett. Org. Chem. 2012, 9, 568-571). The aldehyde was then protected as an acetal with ethane-1,2-diol and p-toluenesulfonic acid. This gives the possibility to carry out lithium-halogen exchange with tert-butyllithium. Trimethylborate is then added and the compound is deprotected by the addition of hydrochloric acid to give (6-formyl-2,3,4-trimethoxyphenyl)boronic acid (after G. Besong, D. Billen, I. Dager, P. Kocienski, E. Sliwinski, LR Tai, FT Boyle, Tetrahderon 2008, 64, 4700-4710). This compound is converted in a Suzuki-Miyaura coupling with methyl 2,2,3,3-tetrafluoro-4-iodobutanoate to give methyl 2,2,3,3-tetrafluoro-4-(6-formyl-2,3,4-trimethoxyphenyl)butanoate (after Y. Zhao, J. Hu, Angew. Chem. Int. Ed. 2012, 51, 1033-1036).

[0073] The porphyrin is then obtained in an acid-catalyzed condensation reaction followed by oxidation with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) (according to JS Lindsey, KA MacCrum, JS Tyhonas, YY Chuang, J. Org. Chem 1994, 59, 579-587). Metallation with nickel acetylacetonate is carried out according to the recipe by M. Dommaschk, F. Gutzeit, S. Boretius, R. Haag, R. Herges, Chem. Commun. 2014, 50, 12476-12478, after which the acid is released by basic ester saponification. The reaction is shown diagrammatically below:

[0074] [ka]

[0075] Example 10 Swab test for detection of TATP A solvent- and acid-resistant wipe (e.g., hydrophilized polypropylene) is used to wipe the surface contaminated with TATP. A solution of 0.5 mg of Ni-porphyrin (structure 2, see Example 8 for preparation) with a (CF2)8 linker and CO2H group as acid dissolved in 10 ml of chloroform is sprayed onto the wipe. A color change from red to green indicates contamination with TATP or another peroxide or nitramine or nitrate-based explosive.

[0076] Example 10 Practical implementation of the test A plastic strip (90 x 5 mm) is equipped at one end with a cellulose pad (5 x 5 mm). The pad is moistened with a solution of Ni-porphyrin in an organic solvent. The solvent is evaporated, leaving the dry pad homogeneously impregnated with red porphyrin. The stick can be stored for a long time (>2 years at room temperature in a dry environment). Before use, the strip is activated by applying a drop (5-10 μL) of perfluoropentanoic acid to the pad. The strip then remains active and ready to use for about 15 minutes. The acid may be applied from a dropper bottle or released by mechanical force from a reservoir above the pad. In these examples, the following detection limits could be determined: TATP: about 40 ng, KClO3: about 270 ng, NH4NO3: about 85 ng, urea nitrate: about 350 ng, HMTD: about 50 ng.

[0077] Comparative Example 1 For comparison, we prepared electron-rich Ni-porphyrin (Ni-tetra(4-hydroxyphenyl)porphyrin) according to M. K. Chahal, M. Sankar, Dalton Trans. 2016, 45, 16404-16412, and cyanide (CN)-containing porphyrin (C-Cyanophenyl)porphyrin (C-Cyanophenyl)porphyrin) according to M. K. Chahal, M. Sankar, Dalton Trans. 2017, 46, 11669-11678. - ), fluoride (F - ), and picric acid. Trifluoroacetic acid (TFA) and TATP and HMDT were added to the Ni-porphyrins used in these publications. After 1 min at room temperature, a non-specific reaction occurred. Therefore, these porphyrins described by Chahal et al. are not suitable for the detection of peroxide-based explosives.

[0078] Comparative Example 2 Ni-tetra(carboxyphenyl)porphyrins bearing COH groups directly attached to the meso-phenyl ring at the 2-, 3-, or 4-positions (B. Du, A. Langlois, D. Fortin, C. Stern, P.D. Harvey, J. Clust. Sci. 2012, 23, 737-751) are not suitable because the carboxylic acid groups are not sufficiently acidic (pK a 4.2) is not. Ni-tetrakis(4-carboxyphenyl)porphyrin (CAS# 136300-60-2) was synthesized (BJ Johnson et al., Sensors 2010, 10, 2315-2331) and dissolved in methylene chloride. TATP and HMDT were added. No color change was observed.

[0079] 1. An analytical method for detecting a compound, comprising the step of contacting a sample suspected of containing a peroxide-based compound, a nitrate-based compound, a nitrotoluene-based compound, or a nitroamine-based compound with a composition comprising Ni-porphyrin and an acid or consisting of Ni-porphyrin and an acid.

[0080] 2. The analytical method according to 1, wherein the compound to be detected is an explosive.

[0081] 3. The peroxide-based explosive is at least one of triacetone triperoxide (TATP), diacetone diperoxide (DADP), methyl ethyl ketone peroxide (MEKP), and / or hexamethylene triperoxide diamine (HMTD), and the nitrate-based explosive is potassium nitrate (KNO3), ammonium nitrate (NH4NO3), urea nitrate (NH2COHNH2 + NO3 - ), nitroglycerin (NG), ethylene glycol dinitrate (EGDN), and / or pentaerythritol tetranitrate (PETN), and the nitroamine explosive is 1,3,5-trinitro-1,3,5-triazinane (hexogen, RDX), 1,3,5,7-tetranitro-1,3,5,7-tetrazoctane (octogen, HMX), 2,4,6-trinitrophenylmethylnitramine (tetryl), 2,4-dinitrotoluene (DNT) or 2,4,6-trinitrotoluene (TNT), and / or nitrourea (NH2CONHNO2).

[0082] 4. The analytical method according to any one of claims 1 to 3, characterized in that the sample is first treated with a superbase before contacting it with Ni-porphyrin and an acid.

[0083] 5. The analytical method according to any one of claims 1 to 4, characterized in that the compounds containing nitroamines and nitrotoluenes are pretreated with an organic superbase before the sample is contacted with Ni-porphyrin and acid.

[0084] 6. The analytical method according to any one of claims 1 to 5, characterized in that nitroamines after treatment with organic superbases are revealed by Ni-porphyrins and eventually give a brown color, while nitrotoluene immediately gives a deep purple color on treatment with superbases.

[0085] 7. The analytical method according to any one of 1 to 6, characterized in that the composition contains an acid-stable solvent.

[0086] 8. The analytical method according to any one of 1 to 7, characterized in that the acid is a free acid.

[0087] 9. The analytical method according to any one of 1 to 8, characterized in that the acid is formed by at least one substituent on Ni-porphyrin.

[0088] 10. The analytical method according to any one of 1 to 9, characterized in that the sample is a gas sample taken from a container or from the environment suspected of containing a peroxide-based explosive.

[0089] 11. An analytical method described in any one of 1 to 10, characterized in that the composition comprising or consisting of Ni-porphyrin, acid and optionally an acid-stable solvent is held by a carrier which is a porous acid-stable material and / or a swellable liquid-adsorbing acid-stable material which forms a gel, the carrier forming a support material for the liquid composition containing Ni-porphyrin and acid.

[0090] 12. Analytical method according to any one of claims 1 to 10, characterized in that the composition comprising or consisting of Ni-porphyrin, an acid and optionally an acid-stable solvent is liquid and is brought into contact with the sample in the form of droplets.

[0091] 13. An analytical method described in any one of 1 to 12, characterized in that a portion of the sample is contacted with a composition comprising Ni-porphyrin and a strong acid to detect any peroxides, and a portion of the sample is contacted with a composition comprising Ni-porphyrin and a weak acid to detect only hydrogen peroxide.

[0092] 14. An analytical method described in any one of 1 to 13, characterized in that the presence of peroxide compounds is detected by Ni-porphyrin and ultimately produces a green color, and the presence of nitrate compounds and nitramine compounds is detected by Ni-porphyrin and ultimately produces a green color.

[0093] 15. A composition for use in an analytical method for detecting a peroxide compound, a nitrate compound, a nitrotoluene compound, or a nitroamine compound, comprising Ni-porphyrin, a pK of -1.2 to 0.23, a and optionally an acid-stable solvent.

[0094] 16. The composition according to claim 15, wherein the acid is a free acid.

[0095] 17. The composition according to claim 15, characterized in that the acid is a substituent on the Ni-porphyrin and is attached to the pyrrole ring of the Ni-porphyrin by an intermediate linker having a chain length of at least one atom, and / or the acid substituent is attached directly or by an intermediate linker to an aryl group substituting the Ni-porphyrin at the meso position, the linker having a chain length of at least one atom.

[0096] 18. A composition according to any one of claims 15 to 17, characterized in that it is carried on a carrier which is porous and / or swellable.

[0097] 19. The composition according to any one of claims 15 to 17, characterized in that it is in solution in an acid-stable solvent.

[0098] 20. The composition according to any one of claims 15 to 19, characterized in that the porphyrin is a Ni-porphyrin substituted at least at one meso position by at least one aryl group substituted with at least one electron-donating group.

[0099] 21. A composition according to any one of claims 15 to 20, characterized in that the Ni-porphyrin is substituted with an acid group which is attached to at least one aryl group by an intermediate linker having a chain length of at least one atom, and / or the porphyrin is substituted with an acid group which is attached to a pyrrole group by an intermediate linker having a chain length of at least one atom, and / or the Ni-porphyrin is substituted with at least one acid group which is directly attached to at least one aryl group which substitutes the Ni-porphyrin in the meso position.

[0100] 22. A composition according to any one of claims 15 to 20, characterized in that in a kit-of-parts, the Ni-porphyrin is present on a porous carrier bound to a plastic piece, in combination with a container containing an acid as a liquid, optionally mixed with an acid-stable organic solvent, and optionally with a container containing a liquid superbase.

[0101] 23. A composition according to any one of claims 15 to 20, characterized in that in a kit-of-parts, in combination with a container containing an acid-stable organic solvent and, optionally, in combination with a container containing a liquid superbase, the Ni-porphyrin has an attached acid group with a pKa between -1.2 and 0.23, and the Ni-porphyrin is present on a porous carrier bound to a plastic piece.

[0102] 24. The composition of any one of claims 15 to 20, characterized in that in a kit-of-parts, optionally in combination with a container containing a liquid superbase, the Ni-porphyrin is mixed with a free acid having a pKa of -1.2 to 0.23, and the Ni-porphyrin and free acid are present in an acid-stable organic solvent in the container.

[0103] 25. The composition of any one of claims 15 to 20, optionally in combination with a container containing a liquid superbase in a kit-of-parts, characterized in that the Ni-porphyrin has an attached acid group having a pKa of -1.2 to 0.23, and the Ni-porphyrin is present in an acid-stable organic solvent in the container.

[0104] 26. A method for producing an analytical device suitable for detecting a compound in a sample, comprising or consisting of the steps of providing a porous and / or swellable carrier, optionally bound to an inert base material, and adding onto the carrier a composition comprising Ni-porphyrin and an acid having a pKa of -1.2 to 0.23 or consisting of Ni-porphyrin and an acid having a pKa of -1.2 to 0.23.

[0105] 27. The method according to claim 26, characterized in that the acid is a free acid or an acid group attached to the pyrrole ring of the Ni-porphyrin by an intermediate linker having a chain length of at least one atom, and / or the acid substituent is attached to an aryl group substituting the Ni-porphyrin in the meso position directly or by an intermediate linker having a chain length of at least one atom.

[0106] 28. The method according to claim 26 or 27, characterized in that the composition is added onto the carrier as a solution in an organic solvent, followed by evaporation of the solvent from the carrier.

[0107] 29. An analytical device suitable for detecting a compound in a sample, comprising or consisting of a porous and / or swellable carrier, optionally bound on an inert base material, said carrier comprising a composition comprising or consisting of Ni-porphyrin and acid.

[0108] 30. The analytical device according to claim 29, characterized in that the acid is a free acid or is attached to the pyrrole ring of the Ni-porphyrin by an intermediate linker having a chain length of at least one atom, and / or the acid substituent is attached to an aryl group substituting the Ni-porphyrin in the meso position directly or by an intermediate linker having a chain length of at least one atom.

Claims

1. An analytical method for detecting a compound, comprising a step of contacting a sample suspected of containing a peroxide-based compound, a nitrate-based compound, a nitrotoluene-based compound, or a nitroamine-based compound with a composition comprising Ni-porphyrin and an acid or consisting of Ni-porphyrin and an acid.

2. 2. The method of claim 1, wherein the compound to be detected is an explosive.

3. The peroxide-based explosive is at least one of triacetone triperoxide (TATP), diacetone diperoxide (DADP), methyl ethyl ketone peroxide (MEKP), and / or hexamethylene triperoxide diamine (HMTD), and the nitrate-based explosive is potassium nitrate (KNO 3 ), ammonium nitrate (NH 4 NO 3 ), urea nitrate (NH 2 COHNH 2 + ・NO 3 - ), nitroglycerin (NG), ethylene glycol dinitrate (EGDN), and / or pentaerythritol tetranitrate (PETN), and the nitroamine explosive is 1,3,5-trinitro-1,3,5-triazinane (hexogen, RDX), 1,3,5,7-tetranitro-1,3,5,7-tetrazoctane (octogen, HMX), 2,4,6-trinitrophenylmethylnitramine (tetryl), 2,4-dinitrotoluene (DNT) or 2,4,6-trinitrotoluene (TNT), and / or nitrourea (NH 2 CONHNO 2 3. The method according to claim 1 or 2,

4. 4. The analytical method according to claim 1, characterized in that the sample is first treated with a superbase before contacting it with Ni-porphyrin and with an acid.

5. 5. The method according to claim 1, characterized in that the compounds containing nitroamines and nitrotoluenes are pretreated with an organic superbase before the sample is contacted with Ni-porphyrin and acid.

6. 6. The analytical method according to any one of claims 1 to 5, characterized in that nitroamines after treatment with organic superbases are revealed by Ni-porphyrins and eventually give a brown color, whereas nitrotoluene immediately gives a deep purple color on treatment with superbases.

7. 7. The analytical method according to claim 1, wherein the composition comprises an acid-stable solvent.

8. 8. The method of claim 1, wherein the acid is a free acid.

9. 9. The analytical method according to claim 1, wherein the acid is formed by at least one substituent on Ni-porphyrin.

10. 10. The analytical method according to any one of claims 1 to 9, characterized in that the sample is a gas sample taken from a container or from the environment suspected of containing a peroxide-based explosive.

11. 11. The analytical method according to claim 1, characterized in that the composition comprising or consisting of Ni-porphyrin, an acid and optionally an acid-stable solvent is held by a carrier which is a porous acid-stable material and / or a gel-forming swellable liquid-adsorbing acid-stable material, the carrier forming a support material for the liquid composition containing Ni-porphyrin and an acid.

12. 11. The analytical method according to claim 1, characterized in that the composition comprising or consisting of Ni-porphyrin, an acid and optionally an acid-stable solvent is liquid and is brought into contact with the sample in the form of droplets.

13. 13. The method of claim 1, further comprising contacting a portion of the sample with a composition comprising Ni-porphyrin and a strong acid to detect any peroxides, and contacting a portion of the sample with a composition comprising Ni-porphyrin and a weak acid to detect only hydrogen peroxide.

14. The analytical method according to any one of claims 1 to 13, characterized in that the presence of peroxide compounds is detected by Ni-porphyrin, eventually resulting in a green color, and the presence of nitrate compounds and nitramine compounds is detected by Ni-porphyrin, eventually resulting in a green color and finally resulting in a brown color.

15. 1. A composition for use in an analytical method for use in detecting peroxide-based compounds, nitrate-based compounds, nitrotoluene-based compounds, or nitroamine-based compounds, comprising Ni-porphyrin, a pK a and optionally an acid-stable solvent.

16. 16. The composition according to claim 15, characterized in that the acid is a free acid.

17. 16. The composition of claim 15, wherein the acid is a substituent on the Ni-porphyrin and is attached to the pyrrole ring of the Ni-porphyrin by an intermediate linker having a chain length of at least one atom, and / or the acid substituent is attached directly or by an intermediate linker to an aryl group substituting the Ni-porphyrin at the meso position, the linker having a chain length of at least one atom.

18. 18. Composition according to any one of claims 15 to 17, characterized in that it is carried on a support which is porous and / or swellable.

19. 18. Composition according to any one of claims 15 to 17, characterized in that it is in solution in an acid-stable solvent.

20. 20. The composition according to claim 15, wherein the porphyrin is a Ni-porphyrin substituted at least at one meso position by at least one aryl group substituted with at least one electron donating group.

21. 21. Composition according to any one of claims 15 to 20, characterized in that the Ni-porphyrin is substituted with an acid group which is linked to at least one aryl group by an intermediate linker having a chain length of at least one atom, and / or the porphyrin is substituted with an acid group which is linked to a pyrrole group by an intermediate linker having a chain length of at least one atom, and / or the Ni-porphyrin is substituted with at least one acid group which is directly linked to at least one aryl group which substitutes the Ni-porphyrin in the meso position.

22. 21. The composition according to any one of claims 15 to 20, characterized in that in a kit-of-parts, the Ni-porphyrin is present on a porous carrier bound to a plastic piece in combination with a container containing an acid as a liquid, optionally mixed with an acid-stable organic solvent, and optionally with a container containing a liquid superbase.

23. 21. The composition according to any one of claims 15 to 20, characterized in that in a kit-of-parts, in combination with a container containing an acid-stable organic solvent and optionally with a container containing a liquid superbase, the Ni-porphyrin has an attached acid group with a pKa between -1.2 and 0.23, the Ni-porphyrin being present on a porous support bound to a plastic piece.

24. 21. The composition of any one of claims 15 to 20, characterized in that in a kit-of-parts, the Ni-porphyrin is mixed with a free acid having a pKa of -1.2 to 0.23, optionally in combination with a container containing a liquid superbase, and the Ni-porphyrin and the free acid are present in an acid-stable organic solvent in the container.

25. 21. The composition of any one of claims 15 to 20, in a kit-of-parts, optionally in combination with a container containing a liquid superbase, characterized in that the Ni-porphyrin has an attached acid group with a pKa of -1.2 to 0.23, and the Ni-porphyrin is present in an acid stable organic solvent in the container.

26. A method for producing an analytical device suitable for detecting a compound in a sample, comprising or consisting of the steps of providing a porous and / or swellable carrier, optionally bound to an inert base material, and adding onto the carrier a composition comprising or consisting of Ni-porphyrin and an acid having a pKa of -1.2 to 0.

23.

27. 27. The method according to claim 26, characterized in that the acid is a free acid or an acid group attached to the pyrrole ring of the Ni-porphyrin by an intermediate linker having a chain length of at least one atom, and / or the acid substituent is attached directly or by an intermediate linker having a chain length of at least one atom to an aryl group substituting the Ni-porphyrin in the meso position.

28. 28. A method according to claim 26 or 27, characterized in that the composition is applied onto the support as a solution in an organic solvent, followed by evaporation of the solvent from the support.

29. An analytical device suitable for detecting a compound in a sample, comprising or consisting of a porous and / or swellable carrier, optionally bound on an inert base material, said carrier comprising a composition comprising or consisting of Ni-porphyrin and acid.

30. 30. The analytical device according to claim 29, characterized in that the acid is a free acid or is attached to the pyrrole ring of the Ni-porphyrin by an intermediate linker having a chain length of at least one atom and / or the acid substituent is attached directly or by an intermediate linker having a chain length of at least one atom to an aryl group substituting the Ni-porphyrin in the meso position.

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