Method of detecting amine-type compounds in air

Abstract

To provide a hydrazine-selective method of directly detecting and, optionally, quantifying hydrazine in air, which is compatible with the presence of high concentrations of interferents and readily performable on site.SOLUTION: There is provided a nanoporous sensor composed of a silicate sol-gel matrix enclosing a reagent composition, the reagent composition including a mixture of 4-(dimethylamino) cinnamaldehyde and polystyrenesulfonic acid. The invention also relates to a method of preparing the same, and the use thereof in the method of detecting at least one amine-type compound, where the compound is selected from hydrazine, ethanolamine, ammonia and morpholine.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a method for treating amine-type compounds, particularly hydrazine (N 2 H 4 The present invention relates to a novel method for detecting and optionally quantitating [Background technology]

[0002] Hydrazine is classified as a CMR substance (IARC 2B-UE 1B). In 2011, it was included in the REACH Candidate List of Substances of Very High Concern. In 2017, the European Union lowered its TLV (8-hour occupational exposure limit value) by a factor of 10 to 10 ppb (0.013 mg / m 3 ), which will apply from 17 January 2020 at the latest. In addition to human health concerns, hydrazine is also classified as extremely toxic to aquatic organisms (EU classifications H400 and H410).

[0003] Due to its CMR properties, hydrazine is no longer an oxidizer for rockets, but it is still used in many fields, in particular in the pharmaceutical and chemical industries as an organic synthesis intermediate, or as a foaming agent for polymer foams, or as a reducing agent for metal salts, or even as a corrosion inhibitor, for example in industrial boiler circulating waters.

[0004] Due to its toxicity, assessment of the risks associated with environmental hydrazine releases is important and there is a need for the ability to detect and optionally quantitate its presence in the environment.

[0005] To date, this risk assessment has been significantly limited by the metrology associated with this substance, especially with regard to direct in-situ measurements. In particular, although certain analytical methods exist that are relatively sensitive (final readout by HPLC-UV), they are not easily performed and are not amenable to industrial implementation. "Instant response" analytical methods are neither selective enough nor accurate and sensitive enough to allow prediction of hydrazine gas concentrations in the final effluents evaluated.

[0006] Hydrazine detection and quantification is currently performed using an indirect method, which involves collecting the ambient air to be analyzed, trapping the hydrazine in an acidified cartridge, and then desorbing it and reacting it with a reagent solution. The adducts formed are then separated by liquid chromatography and analyzed optically.

[0007] In addition to the duration of the method, which includes several steps that are difficult to perform directly at the sampling site, there are some interferences, especially those used to basify the water or resulting from the decomposition of hydrazine, such as ethanolamine (NH 2 EtOH), morpholine or ammonia (NH 3 ), and the potential interference from other gaseous nitrogen compounds is unknown. It is important to be able to directly and selectively measure hydrazine in concentrations ranging from 1 to 100 ppb in dry to very humid air and in the presence of interfering substances whose concentrations can be 50 to 100 times higher than that of hydrazine.

[0008] The method that is the subject of the present invention provides a solution to these problems.

[0009] Specifically, the method according to the present invention is capable of absorbing water vapor, volatile organic compounds and other nitrogen compounds, such as ethanolamine (NH 2In the presence of hydrazine (EtOH), morpholine or ammonia, it allows hydrazine to be selectively detected and optionally quantified. After contact with hydrazine, the sensor used changes color, the color intensity being proportional to the hydrazine content, allowing this compound to be detected and potentially quantified.

[0010] prior art The detection of hydrazine has been the subject of numerous studies, and the methods of detection are as numerous as the types of studies, due to the high chemical reactivity of this compound. -3 Only methods proposed in the literature that can cover the required concentration range (i.e., 1 to 100 ppb) are described.

[0011] Methods for measuring hydrazine in air are particularly useful for concentrations between 1.3 and 130 μg.m -3 In the target range (i.e. 1 to 100 ppb), there are fewer methods available than for the liquid phase. The current method is described in INRS Data Sheet 21. It is based on the use of benzaldehyde. 1 ]. Hydrazine is collected by drawing air through a tube filled with an inert sorbent of 3060 mesh particle size (Chromosorb P NAW or equivalent) impregnated with sulfuric acid. The cartridge contents are desorbed with deionized water and subjected to benzaldehyde derivatization. The adduct benzalazine is measured by liquid chromatography (HPLC) coupled with UV light detection.[ 2, 3 This method is capable of detecting 30 ppb of hydrazine within 15 minutes of sampling.

[0012] A variant of this method is the use of a cassette containing two glass fiber filters impregnated with sulfuric acid. Hydrazine extraction is carried out with an EDTA buffer solution and derivatization with benzaldehyde. The benzalazine formed is measured by liquid chromatography coupled with UV light detection. 4 This assay method provides a N concentration of 0.017 ppb. 2 H 4This shows that the sensitivity is high.

[0013] These two methods do not allow direct measurement at the sampling site, and interference from ammonia or other amines at concentrations 50 to 100 times higher than the hydrazine concentration is unknown.

[0014] Direct measurement methods are also available. Several colorimetric dosimeters have been developed and marketed by laboratories in connection with monitoring worker exposure to hydrazine, monomethylhydrazine (MMH), and 1,1-dimethylhydrazine (UDMH), which are used as rocket fuels at air force bases and space centers in the United States. 5, 6 ]. The principle is based on the incorporation of aromatic aldehydes such as vanillin, para-dimethylaminobenzaldehyde (pDMAB) or 2,4-dinitrobenzaldehyde onto filter paper or an inert surface. Hydrazine and MMH react with vanillin or 2,4-dinitrobenzaldehyde to form yellow compounds, whereas the product formed with pDMAB is orange in color. UDMH reacts with 2,4-dinitrobenzaldehyde to form yellow compounds and therefore does not react with vanillin and pDMAB. Colorimetric dosimeters based on vanillin and para-dimethylaminobenzaldehyde are manufactured by DODTEC [ 7 ] and CHEMSEE 8 They do not allow for precise quantification, but only allow for an estimation of the hydrazine and monomethylhydrazine content in the air from 25 ppb down to 1.2 ppm.

[0015] Patent US00 / 5719061A[ 9In

[2003] , Rose-Pehrsson et al. propose a method allowing the selective detection and quantification of liquid or gaseous hydrazine, monomethylhydrazine and 1,1-dimethylhydrazine by derivatization with aromatic carboxaldehydes and fluorescence analysis. The selectivity is based on the reactivity of three derivatization agents, ortho-phthalaldehyde (OPA), naphthalene-2,3-dicarboxaldehyde (NDA) and anthracene-2,3-dicarboxaldehyde (ADA), with hydrazine, monomethylhydrazine and 1,1-dimethylhydrazine as a function of the pH of the reagent solution. These authors therefore developed a complex device that allows ambient air to be pumped into and sparged from the reagent solution, whose composition (OPA or NDA or ADA) and pH must be modified to generate selectivity. The detection limits achieved are in the ppb, but the analysis of the gas mixture to be analysed requires numerous reagents and pH modification steps followed by fluorescence analysis. Furthermore, interference from other amines, especially at 50 to 100 times higher concentrations that tend to alter the pH of the solution, was not studied.

[0016] For accurate measurements, several commercial devices are available: a portable electrochemical detector, model 4180-100b from Interscan; 10 The hydrazine sensor allows detection of hydrazine in the range of 10 to 100 ppb in less than 1 second, with a high detection limit of 10 ppb. The sensor also detects NH 3 This method is also non-selective since it also detects NOx, CO and other organic amines.

[0017] High sensitivity can be obtained using devices equipped with a photoionization detector (PID), such as the ppbRAE 3000 from RAE. 11 A photoionization detector equipped with a 10.6 eV lamp allows ionization of hydrazine and measurement of several ppb in 3 seconds. However, many volatile organic compounds present in air with ionization potentials below 10.6 eV, such as NH 3 The detection is not selective, since ethanolamine and morpholine are also detected.

[0018] Hydrazine ionization followed by ion mobility measurements using an ion mobility spectrometer (IMS) can achieve contents of about 10 ppb (20-30 ppb) and at the same time are selective in terms of the choice of carrier gas. When a radioactive source is used, the IMS (e.g. the SABRE 4000 portable detector [ 12 ] or Environics 'ChemPro100i[ 13 ]) must be under the control of personnel with good radiation protection. The technique is favored by military and police forces for the detection of chemical weapons and illegal products. Its application in the public has been developed more recently with the development of new non-radioactive ionization sources (corona effect), e.g. the PAIMS portable detector from MaSaTECH [ 14 ] or LCD 3.3[ from Smiths Detection 15 ] etc.

[0019] Prior art in hydrazine measurement shows that only the currently employed simple method using benzaldehyde as a reagent can be used with good selectivity and sensitivity. However, hydrazine measurement in air requires an adsorption step followed by a desorption and derivatization step, followed by optical analysis, which are difficult to perform in situ. Furthermore, this method requires the detection of high concentrations of NH 3 , ethanolamine or morpholine gas interference is unknown. [Prior art documents] [Patent documents]

[0020] [Patent Document 1] Patent US00 / 5719061A [Non-patent literature]

[0021] [Non-Patent Document 1] IUPAC. Compendium of Chemical Terminology, 2nd edition ("Gold Book"), edited by AD McNaught and A. Wilkinson, Blackwell Scientific Publications, Oxford (1997), online version (2019-) created by SJ Chalk, ISBN 0-9678550-9-8, https: / / doi.org / 10.1351 / goldbook Summary of the Invention [Problem to be solved by the invention]

[0022] Thus, there is a real need for a hydrazine-selective method for the direct detection, and optionally, direct quantification, of hydrazine in air that is compatible with the presence of high concentrations of interfering substances and can be easily performed in the field.

[0023] The method according to the present invention addresses these problems. [Means for solving the problem]

[0024] A first subject of the present invention is a nanoporous sensor composed of a nanoporous silicate sol-gel matrix that encapsulates a reagent composition, said reagent composition comprising a mixture of 4-(dimethylamino)cinnamaldehyde and polystyrene sulfonic acid.

[0025] Another subject of the invention is a method for producing a nanoporous sensor according to the invention, comprising: a. synthesizing a sol from an organosilyl precursor in the presence of 4-(dimethylamino)cinnamaldehyde and polystyrene sulfonic acid in a solvent containing water; b. gelling the sol obtained in step a) to obtain a gel; c. drying the gel obtained in step b) to obtain a nanoporous sensor; The method includes:

[0026] The subject of the present invention is also a method for detecting at least one amine-type compound using a nanoporous sensor according to the invention, comprising: the amine type compound is selected from hydrazine, ethanolamine, ammonia and morpholine; The method further comprising: a. placing an analyte gas sample in contact with the nanoporous sensor; b. detecting the amine-type compound with the nanoporous sensor; The method includes:

[0027] Another subject of the invention is the use of a nanoporous sensor according to the invention for the detection and / or quantification of at least one amine type compound, The amine type compound is selected from hydrazine, ethanolamine, ammonia and morpholine.

[0028] The present invention also provides a device for detecting at least one amine-type compound in an analyte gas sample, comprising: the amine type compound is selected from hydrazine, ethanolamine, ammonia and morpholine; The device is a cell enclosing a nanoporous sensor according to the invention, - a gas inlet; - a gas outlet; an optical input section; - Optical output section The present invention relates to a device comprising a cell comprising:

[0029] Other features, details and advantages will become apparent upon reading the following detailed description and upon examining the accompanying drawings. [Brief description of the drawings]

[0030] [Figure 1]FIG. 1 shows a scheme of the reaction between N2H4 and DMACA catalyzed in acidic medium with the formation of DMACA-N2H4 (compound 3) and 2DMACA-N2H4 (compound 4). [Diagram 2] 1 shows difference spectra obtained at different times showing the evolution of absorbance of DMACA-N2H4 and 2DMACA-N2H4 complexes in a Hy3 nanoporous sensor during exposure of the sensor to a stream of a gas mixture containing 14 ppb of N2H4. Spectra are collected every 5 minutes between 0 and 60 minutes. [Diagram 3] 1 shows difference spectra obtained at different times showing the evolution of absorbance of neutral DMACA in a Hy1 nanoporous sensor during exposure of the sensor to a stream of a gas mixture containing 5 ppm of NH3. Spectra are collected every 5 minutes between 0 and 50 minutes. [Figure 4] FIG. 1 shows a schematic diagram of an example of a device according to the invention. [Diagram 5] FIG. 1 shows an example scheme of gas stream flow around a nanoporous sensor installed in a cell according to certain embodiments of the present invention. [Figure 6] FIG. 2 shows a scheme of an example of a cell of a device according to the invention. [Figure 7] Graph showing the evolution of the absorption spectrum of a Hy1 sensor exposed to 5 ppm NH3 (spectra collected every 5 min for 50 min); and the variation in the rate of formation of neutral DMACA as a function of NH3 concentration (right). Stream = 200 mL.min-1, %RH = 50%. [Figure 8] Graph showing calibration curve of Hy3 sensor for detection of N2H4. Variation of 1DMACA-N2H4 complex formation rate at 388 nm as a function of N2H4 concentration. Stream=200 mL.min-1, %RH=50%. [Figure 9] 1 is a graph showing the effect of relative humidity of the gas mixture on the rate of formation of the 1DMACA-N2H4 complex as a function of N2H4 concentration. Stream=200 mL.min-1. [Figure 10]1 is a graph showing the effect of the presence of the potential interferent NH2EtOH on the response of the Hy3 sensor to hydrazine, stream=200 mL.min-1, RH=50%. [Figure 11] 1 is a graph showing the effect of the presence of the potential interferent morpholine on the response of the Hy3 sensor to hydrazine, stream=200 mL.min-1, RH=50%. [Figure 12] 1 is a graph showing the effect of the presence of the potential interferent NH3 on the response of the Hy3 sensor to hydrazine, stream=200 mL.min-1, RH=50%. [Figure 13] 1 is a graph showing the effect of the presence of two potential interferents, NH3 and NH2EtOH, on the response of the Hy3 sensor to hydrazine. Stream=200 mL.min-1, RH=50%. [Figure 14] 1 is a graph showing the effect of the presence of two potential interferents, NH3 and morpholine, on the response of the Hy3 sensor to hydrazine. Stream=200 mL.min-1, RH=50%. [Figure 15] 1 is a graph showing a comparison of Hy1, Hy2 and Hy3 sensor responses to 30 ppb N2H4, stream=200 mL.min-1, %RH=50%. [Figure 16] 1 is a graph showing a comparison of the response of Hy8 and Hy9 sensors to 40 ppb N2H4, stream=200 mL.min-1, %RH=50%. [Figure 17] 1 is a graph showing a comparison of the response of Hy4, Hy5, Hy6 and Hy7 sensors to 25 ppb N2H4, stream=200 mL.min-1, %RH=50%. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0031] The subject of the present invention is a nanoporous sensor composed of a nanoporous silicate sol-gel matrix that encapsulates a reagent composition, said reagent composition comprising a mixture of 4-(dimethylamino)cinnamaldehyde and polystyrene sulfonic acid.

[0032] For the purposes of the present invention, a silicate sol-gel matrix means a material obtained via a sol-gel process consisting of using as precursors silicon alkoxides of formula Si(OR)x, where R is an alkyl group.

[0033] During the sol-gel process, alkoxy groups (OR) are hydrolyzed in the presence of water to form silanol groups (Si-OH). These condense to form siloxane bonds (Si-O-Si-). This results in small particles, generally less than 1 μm in size, which aggregate to form clusters that remain suspended without settling to form a sol. The increase in the clusters and their concentration increases the viscosity of the medium, which then gels. Drying the gel results in a porous solid material, excluding the solvent from the polymer network that is formed (syneresis). Formula Si(OR) x The sol-gel matrices obtained from the silicon alkoxides are referred to as silicate sol-gel matrices in this patent application.

[0034] For purposes of the present invention, the term "nanoporous" means having pores with a size less than 100 nm.

[0035] According to a particular embodiment, the nanoporous matrix according to the invention is an essentially microporous matrix.Accordingly, according to this embodiment, the sensor can also be described as essentially microporous.An essentially microporous material (essentially microporous sensor or essentially microporous matrix) means a material in which at least 80% of the pores are micropores.

[0036] According to the IUPAC definition, a micropore is characterized by a width of 2 nm or less (IUPAC. Compendium of Chemical Terminology, 2nd Edition ("Gold Book"), edited by AD McNaught and A. Wilkinson, Blackwell Scientific Publications, Oxford (1997), online version (2019-) created by SJ Chalk, ISBN 0-9678550-9-8, https: / / doi.org / 10.1351 / goldbook).

[0037] After contact with an amine-type compound, in particular gaseous hydrazine, the nanoporous sensor according to the invention is capable of catalyzing the reaction of hydrazine (N 2 H 4 ) and 4-(dimethylamino)cinnamaldehyde (DMACA) to give DMACA-N 2 H 4 and 2DMACA-N 2 H 4 A color change occurs due to the formation of a complex, and the change in absorbance correlates with the hydrazine content in the air.

[0038] Hydrazine (N 2 H 4 The reaction between 4-(dimethylamino)cinnamaldehyde (DMACA) is advantageously catalyzed by a polymer-derived acid, in particular polystyrene sulfonic acid. The choice of this type of acid, in particular polystyrene sulfonic acid, has many advantages.

[0039] First, this acid is SO 3 It is a high molecular weight polymer that contains H acid functional groups. Therefore, the number of available protons is particularly high, and it is compatible with DMACA and N 2 H 4 This allows the pore acidity to be adjusted to catalyze the reaction between

[0040] Furthermore, low molecular weight inorganic and organic acids have the drawback that acid vapors may be released during the drying process of the sol-gel matrix, which may also lead to evaporation of the acid. Thus, volatile inorganic acids such as HCl (or organic acids such as acetic acid) may evaporate from the sol-gel matrix, leading to a loss of effectiveness or even hindering the functioning of the sensor. This drawback does not exist in the case of acids obtained from polymers such as polystyrene sulfonic acid, since these acids are not volatile.

[0041] Finally, another major advantage of the polymer-derived acids is related to the placement of the acidic polymer chains inside the micropores of the sol-gel matrix: this placement of acidic functional groups inside the pores allows firstly to acidify each pore and secondly to strongly restrict the polymer diffusion inside the pore network and prevent it from migrating towards the sensor surface. The advantages of this method over the currently used one, which relies on hydrazine capture in a cartridge followed by delayed derivatization with a benzaldehyde reagent, are numerous: the sensor according to the invention allows direct, in situ hydrazine measurement; - Especially DMACA-N 2 H 4 Hydrazine determination by measuring the absorbance of the adduct at 388 nm (Figure 1); - 10 to 600mL.min -1 Flow rates can range from 200 mL.min -1 Hydrazine determination by sampling the analyzed air at a flow rate of 100 ppb (the sampling time can vary depending on the concentration of the gas to be detected, for example here 60 min to 5 min for detecting hydrazine at 1 and 100 ppb, respectively); - The total concentration of potential interfering substances is the hydrazine concentration ([N 2 H 4 ]), NH 3 , ethanolamine (NH 2 Selective determination of hydrazine in the concentration range of 1 to 85 ppb in the presence of interfering substances such as ethyl acetate (EtOH) or morpholine; - Allows selective measurement of hydrazine in gas mixtures at relative humidity ranging from 25% to 100%.

[0042] Advantageously, the nanoporous sensor according to the invention is characterized by a high specific surface area for adsorption. In particular, the nanoporous sensor has a specific surface area of ​​700 to 2500 m 2 .g -1 , preferably 800 to 2000 m 2 .g -1 has a specific surface area for adsorption of

[0043] The specific surface area for adsorption, the pore volume and the pore size distribution are determined by analyzing the liquid nitrogen adsorption-desorption isotherm using density functional theory (DFT) models. The BET (Brunauer-Emmett-Teller) method is an analytical method that allows the derivation of the specific surface area for adsorption.

[0044] The nanoporous sensor according to the invention is preferentially between 0.1 and 0.9 cm 3 .g -1 , preferably 0.2 to 0.8 cm 3 .g -1 , and more preferentially from 0.2 to 0.6 cm 3 .g -1 The pore volume represents the volume occupied by the pores per gram of the sensor. The pore volume of the material is obtained from the nitrogen adsorption isotherm at liquid nitrogen temperature.

[0045] Advantageously, the nanoporous sensor according to the invention has a proportion of micropores greater than 75%, preferably greater than 80% and more preferably ranging from 85% to 95%, the remainder up to 100% corresponding to a proportion of mesopores.

[0046] According to the IUPAC definition (IUPAC. Compendium of Chemical Terminology, 2nd Edition ("Gold Book"), edited by AD McNaught and A. Wilkinson, Blackwell Scientific Publications, Oxford (1997), online version (2019-) created by SJ Chalk, ISBN 0-9678550-9-8, https: / / doi.org / 10.1351 / goldbook), the term "micropore" means a pore having a width of 2 nm or less, and "mesopore" means a pore having a width of 2 to 50 nm. Pores with a width of more than 50 nm are called macropores according to the same IUPAC reference.

[0047] The nanoporous sensor according to the invention preferentially has a mesopore content of less than 25%, preferably less than 20% and more preferentially ranging from 5% to 15%, the remainder up to 100% corresponding to the micropore content.

[0048] In particular, a nanoporous sensor according to the invention may have pores with a diameter in the range of 0.3 to 2 nm, preferably 0.5 to 2 nm.

[0049] The nanoporous sensor according to the invention may also be characterized by advantageously having mesopores with a diameter of between 2 and 20 nm, preferably between 2 and 15 nm.

[0050] The nanoporous sensor according to the invention preferably has a ratio r between the polystyrene sulfonic acid concentration and the 4-(dimethylamino)cinnamaldehyde concentration of between 1 and 20, preferably between 2 and 15, and even more preferentially 10.

[0051] This ratio is calculated from the polystyrene sulfonic acid concentration and the molar concentration of 4-(dimethylamino)cinnamaldehyde (r = [H +] / [DMACA]). In this calculation, the molar mass of polystyrene sulfonate monomer (M = 184 g / mol) is used to convert the polystyrene sulfonate (PSS) mass concentration to molar concentration. For example, 9.2 g L -1 The PSS concentration is 0.05 mol.L -1 (=9.2 / 184). Therefore, it corresponds to a concentration of 5.10 -3 mol.L -1 DMACA concentration and 9.2gL -1 (0.05 mol.L -1 ), the ratio r is equal to 10.

[0052] The ratio of the concentrations of polystyrene sulfonic acid and 4-(dimethylamino)cinnamaldehyde is also expressed as the ratio of the mass concentrations of the two species, r' (r' = [H + ] / [DMACA]), the ratio r' ranging from 1 to 20, preferably from 2 to 15, and even more preferentially 11. For example, 0.876 gL -1 (M = 175.23 g.mol -1 ) corresponding to 5.10 -3 mol.L -1 DMACA concentration and 9.2gL -1 At a PSS concentration of , the ratio r' is equal to 10.5.

[0053] Another subject of the invention is a method for producing a nanoporous sensor according to the invention, comprising: a. synthesizing a sol from a selected organosilyl precursor in the presence of 4-(dimethylamino)cinnamaldehyde and polystyrene sulfonic acid in a solvent comprising water; b. forming the sol obtained in step a) and subsequently gelling it to obtain a gel; c. drying the gel obtained in step b) and then demolding to obtain a nanoporous sensor; The method includes:

[0054] According to a preferred embodiment of the method according to the invention, the organosilyl precursors are prepared by rapid hydrolysis and condensation, as well as by the use of precursors that do not have long hydrophobic chains, such as tetramethoxysilane Si(OCH 3 ) 4 ), Methyltrimethoxysilane CH 3 Si(OCH 3 ) 3 , ethyltrimethoxysilane (C 2 H 5 )Si(OCH 3 ) 3 , 3-aminopropyltriethoxysilane (C 3 H 6 NH 2 )Si(OC 2 H 5 ) 3 , 3-aminopropyltrimethoxysilane (C 3 H 6 NH 2 )Si(OCH 3 ) 3 ), (3-(methylamino)propyl)trimethoxysilane (C 3 H 6 NHCH 3 )Si(OCH 3 ) 3 , 3-carboxypropyltriethoxysilane (C 3 H 6 CO 2 H)Si(OC 2 H 5 ) 3 , 3-carboxypropyltrimethoxysilane (Si(C 3 H 6 CO 2 H)(OCH 3 ) 3 ), tetraethoxysilane and mixtures thereof. The precursor is preferentially selected from tetramethoxysilane (TMOS), tetraethoxysilane (TEOS) and mixtures thereof.

[0055] Step a) of the process according to the invention is preferentially carried out in a solvent which may be water or a water / alcohol mixture, the alcohol being preferably a C1-C6 aliphatic alcohol, more preferentially methanol or ethanol, or a mixture of water with a solvent selected from acetone, formamide and methyl ethyl ketone.

[0056] In the method according to the invention, the sol synthesis step a) advantageously begins with the reaction of tetramethoxysilane Si(OCH 3 ) 4 ), Methyltrimethoxysilane CH 3 Si(OCH 3 ) 3 , ethyltrimethoxysilane (C 2 H 5 )Si(OCH 3 ) 3 , 3-aminopropyltriethoxysilane (C 3 H 6 NH 2 )Si(OC 2 H 5 ) 3 , 3-aminopropyltrimethoxysilane (C 3 H 6 NH 2 )Si(OCH 3 ) 3 ), (3-(methylamino)propyl)trimethoxysilane (C 3 H 6 NHCH 3 )Si(OCH 3 ) 3 , 3-carboxypropyltriethoxysilane (C 3 H 6 CO 2 H)Si(OC 2 H 5 ) 3 , 3-carboxypropyltrimethoxysilane (Si(C 3 H 6 CO 2 H)(OCH 3 ) 3), tetraethoxysilane, and mixtures thereof, is mixed with 4-(dimethylamino)cinnamaldehyde in a solvent containing water, followed by the addition of polystyrene sulfonic acid.

[0057] The addition of the polystyrene sulfonic acid is preferably done dropwise, since dissolving the acid in the mixture is exothermic. Alternatively, the addition of the polystyrene sulfonic acid solution may be done by adding it to a mixture of the organosilyl precursor and 4-(dimethylamino)cinnamaldehyde in a solvent, the mixture being maintained at a temperature below 10°C.

[0058] According to a preferred embodiment, step a) of the process according to the invention is characterized in that the molar ratio of organosilyl precursor to solvent ranges from 1 / 20 to 1 / 2, preferably from 1 / 18 to 1 / 3 and even more preferentially from 1 / 16 to 1 / 4.

[0059] Advantageously, step a) of the process according to the invention is carried out at room temperature, the term "room temperature" referring to a temperature of about 20-22°C.

[0060] According to a preferred embodiment, the mixture obtained at the end of step a) is kept stirred before the gelling step b), preferably at room temperature for a period ranging from 2 to 48 hours, preferably 24 hours.

[0061] The gelling step b) may be carried out after the mixture obtained at the end of step a) has been poured into a mould. If such a mould is used, the method according to the invention may comprise, after the drying step c), a step for demolding the nanoporous sensor.

[0062] The gelling step b) may advantageously be carried out at a temperature of between 20 and 25° C., preferably at 22° C., and at a relative humidity of 100%. This step b) preferably has a duration of between 1 and 15 days, preferably between 1 and 5 days, and even more preferentially 2 days.

[0063] The drying step c) may advantageously be carried out in a closed chamber, where humidity and temperature are preferably controlled, for example in a desiccator.

[0064] The drying step c) is advantageously carried out by flushing the closed chamber with a stream of moist inert gas, preferably argon. The relative humidity of the applied gas stream can advantageously be controlled, first at 100%, then reduced stepwise to about 25%. Thus, the humidity in the closed chamber can be reduced during the drying step to reach 25-28% relative humidity.

[0065] This step c) preferably lasts for 15 to 60 days, preferably 20 to 40 days.

[0066] After drying, the nanoporous sensor obtained is stored at a temperature ranging from 2 to 10° C., preferably from 4 to 8° C., and even more preferentially at 6° C., preferentially protected from light.

[0067] The nanoporous sensor according to the invention and obtainable via the method of the invention advantageously has a parallelepiped shape, advantageously with dimensions of the order of millimetres, for example a height of 7.5 to 10.3 mm, a width of 4.8 to 6.4 mm and a thickness of 1 to 1.3 mm.

[0068] Another subject of the invention is a method for detecting at least one amine-type compound in an analyzed gas sample using a nanoporous sensor according to the invention, comprising: the amine type compound is selected from hydrazine, ethanolamine, ammonia and morpholine; The method further comprising: a. placing the analyte gas sample in contact with the nanoporous sensor; b. detecting the amine-type compound in an analyte gas sample with the nanoporous sensor; The method includes:

[0069] The method advantageously allows the selective measurement of amine-type compounds, particularly hydrazine, directly at concentrations in the range of 1 to 100 ppb, in dry to very humid air and in the presence of total concentrations of interfering substances that can be almost 200 times higher than the concentration of the amine, particularly hydrazine, to be detected.

[0070] For the purposes of the present invention, the term "dry air" means air having a moisture content of 25% or less.

[0071] The method according to the invention therefore allows measurements to be carried out on gas samples at relative humidities ranging from 25% to 100%, preferably from 30% to 100%.

[0072] The method according to the invention therefore offers real advantages over prior art methods which are unable to perform this measurement directly over this concentration range, regardless of water content, and in the presence of interfering substances.

[0073] In addition to detection, the method according to the invention may also allow the determination of the concentration of at least one amine type compound in an analyte gas sample, said amine type compound being selected from hydrazine, ethanolamine, ammonia and morpholine. Thus, according to a particular embodiment, the invention relates to a method for the detection and quantification of at least one amine type compound in an analyte gas sample using a nanoporous sensor according to the invention, comprising: the amine type compound is selected from hydrazine, ethanolamine, ammonia and morpholine; The method further comprising: a. placing the analyte gas sample in contact with the nanoporous sensor; b. detecting and quantifying the amine-type compounds in a gas sample to be analyzed with the nanoporous sensor; The present invention relates to a method comprising the steps of:

[0074] Step b) of the method according to the invention may in particular comprise a step of measuring the absorbance of the nanoporous sensor as a function of time.

[0075] An analytical method that allows the detection and determination of the content of hydrazine and interfering substances with primary or secondary amine functions by absorbance measurements as a function of time involves knowing the absorption spectra of 4-(dimethylamino)cinnamaldehyde (DMACA) / polystyrene sulfonic acid (PSS) mixtures in the presence of amine-type compounds, targeting different concentrations of the amine compounds.

[0076] From these absorption spectra, a calibration curve can be established which represents the time evolution of absorbance as a function of concentration for each of the amine type compounds.

[0077] Thus, when a sensor according to the present invention is placed in the presence of an analyte gas sample, the absorbance measurements obtained as a function of time can be correlated with a pre-established calibration curve to determine the presence or absence of an amine-type compound, and optionally its concentration.

[0078] The detection, and optionally the quantification, of hydrazine, ethanolamine, ammonia or morpholine by absorbance measurements is made possible by the reaction that takes place between these compounds and 4-(dimethylamino)cinnamaldehyde (DMACA) in the presence of polystyrene sulfonic acid (PSS), which acts as a catalyst and leads to the formation of complexes with an absorption spectrum detectable in the UV-visible range, for example using a spectrophotometer.

[0079] Therefore, N catalyzed in the presence of polystyrene sulfonic acid 2 H 4 The reaction between DMACA and N is as shown in Figure 1, forming the adduct 1DMACA-N 2 H 4 and 2DMACA-N 2 H 4 This results in the formation of

[0080] These two complexes 1DMACA-N 2 H 4 and 2DMACA-N 2 H 4The formation of these can be visualized by absorption peaks at 388 and 558 nm, respectively (Figure 2).

[0081] In the context of the present invention, the peak at 388 nm is the more sensitive of the two peaks formed and is therefore used to detect and quantify hydrazine. 2 H 4 The complex is DMACA-N for steric and kinetic reasons. 2 H 4 It forms more slowly and in smaller amounts than the complex.

[0082] In the case of ammonia, DMACA(H + ) is NH 3 In the presence of a strong base such as DMACA, it is deprotonated to form neutral DMACA, which exhibits strong absorption at 420 nm (Figure 3). 3 The detection and measurement of the concentration of NH 3 This can be done by measuring the deprotonation rate (corresponding to the rate of absorbance change over time) as a function of concentration (FIG. 7).

[0083] Another subject of the invention is the use of a nanoporous sensor according to the invention for the detection, or the quantification, or the detection and quantification, of at least one amine type compound, said amine type compound being chosen from hydrazine, ethanolamine, ammonia and morpholine.

[0084] The nanoporous sensor according to the invention may be used in dynamic or static mode: the nanoporous sensor may thus be placed in the analyte gas stream and circulated by a fluid circuit, or alternatively, the sensor may be placed in a chamber containing the analyte gas sample.

[0085] Another subject of the invention is a device (1) for detecting at least one amine type compound in a gas sample to be analyzed, comprising: the amine type compound is selected from hydrazine, ethanolamine, ammonia and morpholine; The device is a cell (11) containing a nanoporous sensor according to the invention, - a gas inlet (111); a gas outlet (112); - an optical input section (113); - an optical output unit (114); The device (11) comprises a cell (11) comprising:

[0086] Advantageously, the device according to the invention comprises a fluid circuit suitable for circulating the analyte gas sample through the cell (11) and generating a gas stream from the gas inlet (111) to the nanoporous sensor and then to the gas outlet (112).

[0087] According to a preferred embodiment, the fluid circuit according to the invention comprises a flow rate regulator (2) suitable for regulating the flow rate of the gas stream. The flow rate regulator (2) may consist of a shutoff valve (21) and a control needle valve (22).

[0088] Advantageously, the device according to the invention also comprises a light source (3) and a spectrophotometer (4), the optical input (113) of the cell being connected to the light source (3) and the optical output (114) of the cell being connected to the spectrophotometer (4). The light source (3) and the spectrophotometer (4) may thus constitute the optical analysis part of the device.

[0089] According to a preferred embodiment, the fluidic circuit of the device according to the invention also comprises a temperature sensor suitable for measuring the temperature of the gas stream.

[0090] Advantageously, the device according to the invention also comprises a humidity sensor suitable for measuring the humidity of the gas stream.

[0091] Advantageously, the device according to the invention also comprises a flow meter (5) suitable for measuring the gas stream flow rate.

[0092] Therefore, in the fluid circuit, the gas mixture flow rate required to expose the sensor, which may vary, for example, from 50 to 600 mL / min depending on the sensor; - measuring the temperature and relative humidity of the gas mixture; - Measurement circuit purge mode and may be taken into consideration.

[0093] Thus, the device according to the invention may operate in the following manner: the air or gas sample to be analysed may be drawn using a pump (6), which may be small, and passed first through an inlet manifold (7), where the temperature and humidity of the gas sample are measured. The manifold (7) may then distribute the gas sample to two outlets. The pump may have a flow rate in particular in the range of 50 to 1100 ml / min.

[0094] The first outlet may move air towards a cell (11) containing a nanoporous sensor. The cell may be placed upstream of a flow meter (5) connected to an output manifold (8) which is itself connected to a pump (6). The flow meter allows for setting the gas stream velocity within the exposure cell.

[0095] A second outlet of the inlet manifold (7) may be connected to the outlet manifold (8) via a shutoff valve (21) and a control needle valve (22). This assembly then constitutes a leakage circuit. This arrangement allows the pump to run continuously at a fixed flow rate, e.g. 1.1 L / min, while the exposure flow rate of the sensor can be changed (if different types of sensors are used). The shutoff valve allows the leakage circuit to be shut off in order to purge the measurement circuit if necessary.

[0096] The optical analysis part includes a light source (3) capable of probing the sensor and a spectrophotometer (4), the latter of which may be small, that collects the light transmitted by the sensor and converts it into an electrical current. The spectrophotometer (4) may operate at wavelengths ranging from UV through the visible range to IR, the wavelength being chosen according to the measurements to be made.

[0097] The light source (3) may consist of two LEDs connected by an optical fiber, or a small lamp. The light source may be a UV light or a visible light or a UV-Visible light source.

[0098] Hydrazine at 388 nm, NH at 420 nm 3 For the detection of ethanolamine at 474 nm or morpholine at 490 nm, the combination of UV LEDs and visible LEDs provides a wavelength range of 380 to 800 nm. Depending on the optical response of the sensor, the choice of other LEDs is also possible. The light is transmitted to the exposure cell, for example using an optical fiber. At the output of the exposure cell, the transmitted light is transmitted to a compact spectrophotometer (4) with a wide response range, for example from 337.5 to 822 nm.

[0099] An example of a device according to the present invention is shown in FIG.

[0100] According to a preferred embodiment, the device according to the invention comprises: the cell comprises a nanoporous sensor support and a parallelepiped, preferably cubic, case with four sides and a front face forming a housing for receiving the nanoporous sensor support in its centre, Two opposing sides represent the gas inlet and outlet, The two opposing sides represent the optical input and output portions; The front surface has an opening for inserting the nanoporous sensor support into the housing. This is characterized by the following (Figure 6).

[0101] A cell of a device according to the invention may therefore comprise two elements.

[0102] The first element is the body, which may consist of a square block of brass, for example reinforced with an inner layer of stainless steel, in particular hollow in its center and possibly with holes on all four sides (Figure 6). Two perpendicular tunnels may thus be formed to serve as passages for the gas stream and the probe light. This block may thus comprise the light input and output, as well as the gas inlet and outlet.

[0103] The second element may be a removable part, for example made of stainless steel (FIG. 6), which also has holes on all four sides to allow the passage of gas streams and light. The sealing of the two tunnels between the external block and the removable part may be achieved using O-rings. The removable part may contain a nanoporous sensor in its center, which may be, for example, a transparent monolithic block with maximum dimensions of about 10 millimeters, for example 11×6.5×2 mm. The optical input and output may each contain a lens to collimate the analytical light beam. The optical input may be connected via an optical fiber to a UV or visible light source or a combination of both UV-visible, and the optical output may be connected via a second optical fiber to a UV or visible or UV-visible spectrophotometer required for the analysis and compatible with the lamps.

[0104] An example of a cell of a device according to the present invention is shown in FIG.

[0105] The sensor can be exposed to the gas stream over its entire length and on both sides. A probe light beam emitted from a light source and carried by an optical fiber strikes the gas stream perpendicularly and is focused onto the sensor at the fiber exit. The surface to be probed is 5.7 mm 2 The optical path of the analysis, which may range from 1 to 2 mm, corresponds to the thickness of the inserted nanoporous sensor.

[0106] Depending on the geometry of the sensor, such as a disk or parallelepiped, the removable portion may be designed to correctly position the sensor and expose it to the gas stream over its maximum surface area.

[0107] According to a preferred embodiment, the sensor is positioned between two half cylinders that are hollowed out to allow the gas stream to pass above and below the sensor (FIGS. 5 and 6). The sensor is positioned at the intersection of a vertical hole through which the probe light can pass.

[0108] According to a preferred embodiment, the device according to the invention is characterized in that the nanoporous sensor support comprises two diametrically opposed through holes optically coupled to the optical input and output.

[0109] Advantageously, the device according to the invention also comprises a computer and a battery that powers said device and thus makes it energetically self-sufficient.

[0110] A device according to the invention may also be equipped with a screen allowing a user to interact with the elements of the system via a computer.

[0111] A device according to the invention may also include a power supply and a control board.

[0112] Thus, the components of the device consisting of the fluidic circuitry and the optical analysis part may be located in a compartment of a portable element, which may then include a second compartment containing a computer suitable for controlling the measurements and a third compartment containing a power source for operating the device as a whole.

[0113] Thus, according to a particular embodiment, the device according to the invention may be integrated into a case with several levels, in particular three levels: for example, the computer may be located at the top level of the case, the device according to the invention at the middle level and the power supply at the bottom level.

[0114] According to a preferred embodiment, the device according to the invention is characterized in that it is portable.

[0115] Advantageously, the device according to the invention allows the quantitative determination of said amine type compounds in an analyzed gas sample. EXAMPLES

[0116] Example 1 Synthesis of nanoporous sensors according to the present invention. Reagents used: Tetramethyl orthosilicate (TMOS), purity 99%, CAS: 681-84-5, molar mass = 152.22 g.mol -1 and density d = 1.023 g.cm -3 4-(Dimethylamino)cinnamaldehyde (DMACA), purity ≥ 98%, CAS: 6203-18-5, molar mass = 175.23 g.mol -1 Polystyrene sulfonic acid (PSS), 30% aqueous solution, CAS: 28210-41-5, molar mass = 75000 g.mol -1 and density d = 1.1 g.cm -3 Para-toluenesulfonic acid (C 7 H 7 -SO 3 H), purity ≥ 98%, CAS: 6192-52-5, molar mass = 190.22 g.mol -1 Ultra-pure deionized water.

[0117] Example 1.1 Hy1 Sensor In a 1L bottle, 14.2mg of DMACA, 40.969mL of H 2 Mix 84.598 mL of TMOS and 1.0 mL of 10% PSS. Keep the solution stirred at room temperature and add 0.449 mL of 30% PSS dropwise, since dissolving PSS in the mixture is exothermic. The molar ratio of silylated precursor to water in the mixture is TMOS / H2O. 2The final concentrations of DMACA and PSS were 6.25 x 10 -4 M and 1.18gL -1 , i.e. [H + ] is approximately 6.25 x 10 -3 It's M.

[0118] The sol was left stirring at room temperature for 24 hours and then 0.3 cm 3 The mixture is poured into a polypropylene mold containing 350 wells with a volume of 100 mL. The mold is placed in a 10 L desiccator maintained at 100% relative humidity until the sol gels. For Hy1, this process takes 2 days at 22°C. The desiccator is then filled with 300 mL.min -1 Drying of the gel is performed by washing with a stream of moist Ar. The relative humidity of the Ar stream, initially 100%, is reduced stepwise to 80%, 50% and then 0%. Drying takes about one month at 22 °C, during which the humidity in the desiccator is reduced to 25-28% relative humidity. The mold is then removed from the desiccator. After removal from the mold, a parallelepiped sensor with dimensions of 9.6 (H) * 6.0 (L) * 1.26 (thickness) mm is obtained with 0.3 mL of initial solution. The final volume of the resulting sensor has shrunk by a factor of 4.2. Store the sensor in a cool place at 6 °C protected from light.

[0119] (Example 1.2) Hy2 Sensor 14.2 mg DMACA, 84.598 mL TMOS, 40.969 mL deionized H 2 The same procedure as for Hy1, using 0 and 0.673 mL of 30% PSS. The molar ratio of the silylated precursor to water in the mixture was TMOS / H 2 The final concentrations of DMACA and PSS were 6.25 x 10 -4 M and 1.77gL -1 , i.e. [H + ] is approximately 9.38 x 10 -3M. The gelation time of the sensor in a desiccator maintained at RH=100% is 2 days at 22°C. Stepwise drying at RH=80%, from 50% to 0%, takes about 40 days at 22°C, during which the humidity in the desiccator reduces to 25-28% relative humidity. After removal from the mold, a sensor is obtained with dimensions of 9.7(H)*6.1(L)*1.26(thickness) mm and a shrinkage factor of 4. Store the sensor in a cool place at 6°C protected from light.

[0120] (Example 1.3) Hy3 Sensor 28.5 mg DMACA, 84.598 mL TMOS, 40.969 mL deionized H 2 The same procedure as for Hy1, using 0 and 0.898 mL of 30% PSS. The molar ratio of silylated precursor to water in the mixture was TMOS / H 2 The final concentrations of DMACA and PSS were 1.25 x 10 -3 M and 2.34gL -1 , i.e. [H + ] is approximately 1.25 x 10 -2 M. The gelation time of the sensor in a desiccator maintained at RH=100% is 2 days at 22°C. Stepwise drying at RH=80%, from 50% to 0%, takes about 1 month at 22°C, during which the humidity in the desiccator reduces to 25-28% relative humidity. After removal from the mold, a sensor is obtained with dimensions of 9.5(H)*6.1(L)*1.24(thickness) mm and a shrinkage factor of 4.2. Store the sensor in a cool place at 6°C protected from light.

[0121] Example 1.4 Hy4 Sensor 113 mg DMACA, 81.496 mL H 2 The same procedure as for Hy1, using 43.91 mL of TMOS and 3.563 mL of 30% PSS. The molar ratio of the silylated precursor to water in the mixture was TMOS / H 2 The final concentrations of DMACA and PSS were 5×10 -3 M and 9.2gL -1, i.e. [H + ] is about 5 × 10 -2 M. Gelation of the sensor in a desiccator maintained at RH=100% occurs after 5 days at 22 °C. Stepwise drying at RH=80%, from 50% to 0%, takes about 1.5 months at 22 °C, during which the humidity in the desiccator reduces to 25-28% relative humidity. After removal from the mold, a sensor is obtained with dimensions of 8.37 (H) * 4.94 (L) * 1.03 (thickness) mm and a shrinkage factor of 7. Store the sensor in a cool place at 6 °C protected from light.

[0122] Example 1.5 Hy5 Sensor 87.9mg DMACA, 33.777mL TMOS, 13.587mL H 2 The same procedure as for Hy1, using 2.77 mL of 30% PSS and 2.0 mL of 30% SiO. The molar ratio of the silylated precursor to water in the mixture was TMOS / H 2 The final concentrations of DMACA and PSS were 1×10 -2 M and 18.4gL -1 , i.e. [H + ] is approximately 1×10 -1 M. The gelation time of the sensor in a desiccator maintained at RH=100% is 5 days at 22°C. Stepwise drying at RH=80%, from 50% to 0%, takes about one month at 22°C, during which the humidity in the desiccator reduces to 25-28% relative humidity. After removal from the mold, a sensor is obtained with dimensions of 10.2(H)*6.4(L)*1.3(thickness) mm and a shrinkage factor of 3.5. Store the sensor in a cool place at 6°C protected from light.

[0123] Example 1.6 Hy6 Sensor The same procedure as for Hy1, using 226 mg DMACA, 43.91 mL TMOS, 77.933 mL water, and 7.126 mL PSS. The molar ratio of silylated precursor to water in the mixture was TMOS / H 2 The final concentrations of DMACA and PSS were 1 x 10 -2 M and 18.4gL-1 , i.e. [H + ] is approximately 1×10 -1 M. The gelation time of the sensor in a desiccator maintained at RH=100% is 3 days at 22°C. Stepwise drying at RH=80%, 50% to 0%, takes about 49 days at 22°C, during which the humidity in the desiccator reduces to 25-28% relative humidity. After removal from the mold, a sensor is obtained with dimensions of 8.4(H)*5.0(L)*1.05(thickness) mm sensor and a shrinkage factor of 6.7.

[0124] Example 1.7 Hy7 Sensor 56.5 mg DMACA, 21.258 mL H 2 Mix 10.974 mL of TMOS and 10.974 mL of toluene in a 1 L bottle. While the solution is kept stirring at room temperature, add 613 mg of para-toluenesulfonic acid, C 7 H 7 -SO 3 H is added slowly. When acid is added to this mixture, the mixture releases heat. The molar ratio of the silylation precursor to water is TMOS / H 2 The final concentration of each of DMACA and para-toluenesulfonic acid was 1×10 -2 M and 1×10 -1 It's M.

[0125] The sol is left stirring at room temperature for 3 hours and then poured into a polypropylene mold. The mold is placed in a 10 L desiccator maintained at 100% relative humidity until the sol gels. This process takes 5 days at 22°C. The desiccator is filled with 300 mL.min -1 Drying is performed by gradually reducing the relative humidity in the desiccator from 100% to 80%, 50%, and then 0% RH while rinsing with an Ar stream. Drying takes about one month at 22 °C, during which the humidity in the desiccator reduces to 25-28% RH. The mold is removed from the desiccator. After removal from the mold, a parallelepiped-shaped sensor is obtained with dimensions of 7.57 (H) * 4.8 (L) * 1.0 (thickness) mm and a shrinkage factor of 8.2. Store the sensor in a cool place at 6 °C protected from light.

[0126] (Example 1.8) Hy8 Sensor Same procedure as for Hy1, using 1.139 g DMACA, 84.598 mL TMOS, 5.054 and 35.916 mL 30% PSS. The final concentrations of DMACA and PSS, respectively, were 5 × 10 -2 M and 95.2gL -1 , i.e. [H + ] is about 5 × 10 -1 M. The gelation time of the sensor in a desiccator maintained at RH=100% is 4 days at 22°C. Stepwise drying at RH=80%, 50% to 0%, takes about one month at 22°C, during which the humidity in the desiccator decreases to 25-28% relative humidity. After removal from the mold, a sensor is obtained with dimensions of 11.2(H)*6.4(L)*1.2(thickness) mm and a shrinkage factor of 3.4.

[0127] Example 1.9 Hy9 Sensor Same procedure as Hy1, using 596.5 mg DMACA, 84.598 mL TMOS, 23.012 mL water and 17.958 mL 30% PSS. The molar ratio of silylated precursor to water was TMOS / H 2 The final concentrations of DMACA and PSS were 2.5 x 10 -2 M and 47.6gL -1 , i.e. [H + ] is approximately 2.5 x 10 -1 M. The gelation time of the sensor in a desiccator maintained at RH=100% is 2 days at 22°C. Stepwise drying at RH=80%, 50% to 0%, takes about 1 month at 22°C, during which the humidity in the desiccator decreases to 25-28% relative humidity. After removal from the mold, a sensor is obtained with dimensions of 10.24(H)*6.5(L)*1.25(thickness) mm and a shrinkage factor of 3.6.

[0128] liquid N 2 N at a temperature of 2The pore characteristics of the nanoporous sensor, such as the specific surface area, pore volume or size distribution for the adsorption of micropores and mesopores, were determined by establishing the adsorption-desorption isotherms. The following table lists these data.

[0129] [Table 1]

[0130] The percentages of micropores and mesopores given here correspond to the distribution of the adsorption surface area as a function of the pore diameter, which may differ when considering the pore volume distribution as a function of the pore diameter.

[0131] Example 2 NH 3 Hy1 sensor response to 5 ppm NH 3 The Hy1 sensor was exposed to a humid gas mixture (relative humidity RH=50%) containing NH 3 DMACA(H + ), but does not react with DMACA(H + ) to form neutral DMACA. In the porous material, neutral DMACA exhibits a broad absorption band in the UV-near-visible range with a maximum centered at 420 nm (Figure 7). 3 The Hy1 sensor calibration curve corresponding to the rate of formation of neutral DMACA as a function of concentration is shown in FIG.

[0132] Example 3 N 2 H 4 Hy3 sensor response to N 2 H 4 Establishing calibration curves for gases The Hy3 sensor was tested at different concentrations of N over a wide concentration range from 1 to 114 ppb. 2 H 4 The relative humidity of the gas mixture remained fixed at 50%. 2 H 4 For each exposure to the concentration, 1DMACA-N at 388 nm 2H 4 The rate of complex formation was derived. 2 H 4 1DMACA-N as a function of concentration 2 H 4 By plotting the rate of complex formation, N at 388 nm 2 H 4 A calibration curve for the detection of N was established for the Hy3 sensor. 2 H 4 An example of a calibration curve is shown in FIG.

[0133] Figure 8 shows the N produced by exposing the Hy3 sensor to storage times ranging from 5 to 15 months. 2 H 4 The calibration curve for 1DMACA-N 2 H 4 The linear variation of the complex formation rate is N 2 H 4 as a function of concentration. -1 and ΔAbs=0.02), the detection limit is 1 ppb. The exposure time can be reduced by increasing the flow rate of the analyte gas mixture.

[0134] Example 4 N at various relative humidities 2 H 4 Response of Hy3 sensor to Hy3 Sensor N 2 H 4 The effect of the relative humidity of the gas mixture on the calibration curve is investigated (Figure 9). For this purpose, the N concentration in the gas mixture at 30%, 50% and 80% RH is measured. 2 H 4 The Hy3 sensor is exposed to

[0135] Example 5 Potential interferent NH 2 N in the presence of EtOH 2 H 4 Hy3 sensor response to NH 2 N in the presence of EtOH 2H 4 To test the response of the Hy3 sensor to N 2 H 4 +NH 2 The Hy3 sensor is exposed to a gas mixture containing EtOH.

[0136] Example 6 N in the presence of the potential interferent morpholine 2 H 4 Hy3 sensor response to N in the presence of morpholine 2 H 4 To test the response of the Hy3 sensor to N 2 H 4 + Expose the Hy3 sensor to a gas mixture containing morpholine.

[0137] Example 7 Potential interferent NH 3 N in the presence of 2 H 4 Hy3 sensor response to NH 3 N in the presence of 2 H 4 To this end, we tested the response of the Hy3 sensor to N 2 H 4 +NH 3 The Hy3 sensor is exposed to a gas mixture containing

[0138] Example 8 Two potential interfering substances, NH 3 and N.H. 2 N in the presence of EtOH 2 H 4 Hy3 sensor response to Two potential interfering substances, NH 3 and N.H. 2 N in the presence of EtOH 2 H 4 To test the response of the Hy3 sensor to N 2 H 4 +NH 3 +NH2 The Hy3 sensor is exposed to a gas mixture containing EtOH.

[0139] Example 9 Two potential interfering substances, NH 3 and N in the presence of morpholine 2 H 4 Hy3 sensor response to Interfering substance NH 3 and N in the presence of morpholine 2 H 4 To test the response of the Hy3 sensor to N 2 H 4 +NH 3 + Expose the Hy3 sensor to a gas mixture containing morpholine.

[0140] Example 10 30 ppb N 2 H 4 Comparison of the responses of Hy1, Hy2, and Hy3 sensors to N 2 H 4 The response of the Hy1, Hy2 and Hy3 sensors to 30 ppb of N is examined (Figure 15). 2 H 4 Exposed to.

[0141] Example 11 40 ppb N 2 H 4 Comparison of Hy8 and Hy9 sensors in N 2 H 4 The response of the Hy8 and Hy9 sensors to 40 ppb of N is examined (Figure 16). 2 H 4 Exposed to.

[0142] Example 12 25 ppb N 2 H 4 Comparison of sensors Hy4, Hy5, Hy6 and Hy7 in N2 H 4 The response of the Hy4, Hy5, Hy6 and Hy7 sensors to 25 ppb of N is examined (Figure 17). 2 H 4 Exposed to.

[0143] References list (References) TIFF2025079339000002.tif171154

Claims

1. A nanoporous sensor comprised of a silicate sol-gel matrix containing a reagent composition, comprising: The nanoporous sensor, wherein the reagent composition comprises a mixture of 4-(dimethylamino)cinnamaldehyde and polystyrene sulfonic acid.

2. From 700 to 2500 m 2 .g -1 , preferably 800 to 2000 m 2 .g -1 2. The nanoporous sensor according to claim 1, characterized in that it has a specific surface area for the adsorption of

3. 0.1 to 0.9 cm 3 .g -1 , preferably 0.2 to 0.8 cm 3 .g -1 , and more preferentially from 0.2 to 0.6 cm 3 .g -1 3. The nanoporous sensor according to claim 1 or 2, characterized in that it has a pore volume of

4. 4. A nanoporous sensor according to any one of claims 1 to 3, characterized in that it has a proportion of micropores greater than 75%, preferably greater than 80% and more preferentially ranging from 85% to 95%, the remainder up to 100% corresponding to a proportion of mesopores.

5. A method for preparing a nanoporous sensor according to any one of claims 1 to 4, comprising the steps of: a. synthesizing a sol from an organosilyl precursor in the presence of 4-(dimethylamino)cinnamaldehyde and polystyrene sulfonic acid in a solvent containing water; b. forming the sol obtained in step a) and subsequently gelling it to obtain a gel; c. drying the gel obtained in step b) and then removing it from the mold to obtain a nanoporous sensor. A method comprising:

6. 6. The method according to claim 5, characterized in that the organosilyl precursor is selected from tetramethoxysilane, methyltrimethoxysilane, ethyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, (3-(methylamino)propyl)trimethoxysilane, 3-carboxypropyltriethoxysilane, 3-carboxypropyltrimethoxysilane, tetraethoxysilane and mixtures thereof.

7. A method for detecting at least one amine type compound in an analyte gas sample using a nanoporous sensor according to any one of claims 1 to 4, comprising the steps of: the amine type compound is selected from hydrazine, ethanolamine, ammonia and morpholine; The method further comprising: a. placing the analyte gas sample in contact with the nanoporous sensor; b. detecting the amine-type compound in an analyte gas sample with the nanoporous sensor; A method comprising:

8. 8. The method of claim 7, wherein step b) also comprises quantifying the amine-type compounds in the analyte gas sample at the nanoporous sensor.

9. 5. Use of the nanoporous sensor according to any one of claims 1 to 4 for the detection or quantification or the detection and quantification of at least one amine type compound, wherein said amine type compound is selected from hydrazine, ethanolamine, ammonia and morpholine.

10. A device (1) for detecting at least one amine-type compound in an analyte gas sample, comprising: the amine type compound is selected from hydrazine, ethanolamine, ammonia and morpholine; The device is a cell (11) enclosing a nanoporous sensor according to any one of claims 1 to 4, - a gas inlet (111); a gas outlet (112); - an optical input section (113); - an optical output unit (114); The device (1) comprises a cell (11) comprising:

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