Method of detecting amine-type compounds in water and air compartments

Abstract

To provide a hydrazine-selective method of detecting and, optionally, quantifying hydrazine that can be used in water and air compartments, which is compatible with the potential presence of high concentrations of interferents, is readily performable on site, and enables measurement to be performed with a delay of up to at least 24 hours.SOLUTION: There is provided a method of detecting at least one amine-type compound using a reagent composition including a mixture of 4-(dimethylamino)cinnamaldehyde and polystyrenesulfonic acid, where the compound is selected from hydrazine, ethanolamine, and morpholine. The invention also relates to the reagent composition and uses thereof.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention provides an amine-type compound, particularly hydrazine (N 2 H 4 The present invention relates to a novel method for detecting, and optionally quantifying, [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 the 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] The method that is the subject of the present invention provides a solution to these problems.

[0007] Specifically, the method according to the invention uses a potential buffer substance that acts to basify water or that is obtained from hydrazinolysis, such as ethanolamine (NH 2 EtOH), morpholine or ammonia (NH 3 ), allowing hydrazine to be selectively detected and optionally quantified. 2 EtOH, morpholine and NH 3 The concentration of can be up to 100 to 200 times higher than the concentration of hydrazine without reducing the effectiveness and accuracy of the detection method according to the invention.

[0008] The reagents used also react with these other amines at the same time to form coloured compounds different from those formed by hydrazine.The method therefore makes it possible to detect and determine the concentration of ethanolamine or morpholine at the same time as that of hydrazine, which may allow, for example, the correct basification of water to be verified.

[0009] Furthermore, detection and quantification of hydrazine may need to be performed in both water and air bodies, which the method according to the present invention makes possible.

[0010] In water bodies, samples were collected for analysis of target compounds (N 2 H 4 ) volatility and interference substances (NH3 , N.H. 2 The analytical method should be such that the material is collected for analysis without loss due to the volatility of the solvents (EtOH, morpholine). 2 H 4 The concentration of N in water bodies must be selective for N 2 H 4 The concentration range is 0.2 to 200 μg.L -1 (i.e., 0.2 to 200 ppb).

[0011] In the air, molecular oxygen (O 2 ), water vapor and VOCs (volatile organic compounds) plus other nitrogen compounds (N 2 H 4 , N.H. 3 , N.H. 2 Ambient air containing 1.3 to 264 μg.m2 of ethanol is collected. -3 The objective of the present invention is to selectively measure hydrazine gas over a wide concentration range (i.e., 1 to 200 ppb) and to quantitate potential nitrogen interferents. Analysis should be capable of being performed in situ or after a 24 hour delay in the laboratory.

[0012] The detection of hydrazine has been the subject of numerous studies, and detection methods are as numerous as the types of studies due to the high chemical reactivity of this compound. However, most studies have focused on measuring hydrazine in water or in air. Methods that can be implemented in both water and air are rare or have not been explored further.

[0013] Therefore, in the following description of the prior art, water and air bodies are treated separately and the required concentration ranges in water and air bodies, i.e., 0.2 to 200 μg.L, respectively, are given. -1 (i.e., 0.2 to 200 ppb) and 1.3 to 264 μg.m -3 Only methods proposed in the literature that can cover the 500 ppb range (i.e. 1 to 200 ppb) are described.

[0014] prior art Detecting Hydrazine in Water Hydrazine is a strong reducing agent, a good nucleophile, and also a base, so its nucleophilic, reducing, or basic properties can be used to obtain detection.

[0015] Detection based on nucleophilic properties is the most widely studied method and is mainly based on nucleophilic substitution reactions on the carbonyl group of aromatic aldehydes forming light-absorbing and / or fluorescent colored products. para-Dimethylaminobenzaldehyde (pDMAB) is the method most commonly used industrially. Para-Dimethylaminobenzaldehyde reacts with hydrazine in acidic medium to produce the adduct p-Dimethylaminobenzalazine, which exhibits absorption in the visible range with its maximum centered at 458 nm or 454 nm depending on the surrounding medium. The molar extinction coefficient of p-Dimethylaminobenzalazine is about 60000 L.mol -1 ·cm -1 [ 1, 2, 3 ], and the detection limit for hydrazine with this reagent is 4.7 μg L−1 when the assay is performed using a spectrophotometric cell with a 5 cm light path. -1 Due to the instability of p-dimethylaminobenzalazine, its detection is time-limited and it is not possible to perform delayed measurements beyond 16 hours. Based on this method, modifications of the reaction have been made by several teams to improve the hydrazine detection procedure and / or sensitivity.

[0016] George et al. 4

[1996] improved the sensitivity by first generating 2,4-dinitrophenylhydrazine in situ by reacting hydrazine with 2,4-dinitrochlorobenzene in the presence of sodium acetate and diethylene glycol. 2,4-Dinitrophenylhydrazine is an excellent reagent for the detection and assay of carbonyl groups, which then reacts with pDMAB in acidic medium to form a yellow hydrazone. The hydrazone, which absorbs at 458 nm, has an extremely high molar extinction coefficient (ε 458nm ≒81,000 L.mol -1.cm -1 ), which can increase the measurement sensitivity. However, this method uses 2,4-dinitrochlorobenzene, a reproductive toxic and carcinogenic compound. In addition, the method is long and complicated because the detection procedure involves the following five consecutive steps, which are difficult to perform in situ: 1) formation of 2,4-dinitrophenylhydrazine by heating the mixture until the volume is reduced to half of the initial volume; 2) Reaction of 2,4-dinitrophenylhydrazine with pDMAB, 3) Cooling the mixture to room temperature; 4) the addition of HCl to form the final product; 5) UV-visible assay at 458 nm of the final product.

[0017] Ortega-Barrales et al. 5 In a study by [ 2002 ], the sensitivity is improved by assaying the colored product (benzalazine) on the solid phase, where Dowex 5OWx8 ion exchange resin is added to the reaction medium to capture and concentrate the benzalazine. The benzalazine is bound to the Dowex beads by centrifugation. The resin is then recovered by filtration and the benzalazine adsorbed on the clear resin is assayed on the solid phase by spectroscopy at 464 nm. The detection limit is approximately 0.016 μg.L for a liter of sample. -1 Although this method is highly sensitive, its technical nature makes it difficult to use in the field.

[0018] For the hydrazine assay, other substituted benzaldehydes, such as vanillin [ 6 ], Veratraldehyde [ 7 ], 2-hydroxy-1-naphthaldehyde [ 8 ] and 5-nitro-2-furaldehyde [ 9

[14] has also been studied. These four probe molecules are less reactive than pDMAB, and the reactions were carried out at higher temperatures.

[0019] In recent years, several teams have developed selective hydrazine detection methods based on fluorescent probes, mainly to determine the presence of hydrazine in drinking water, raw water (rivers, etc.), and especially in living cells. Fluorescent probes are generally aromatic polycyclic molecules that have one or two electrophilic sites that can react with hydrazine.

[0020] Roy et al. 10 ], Nguyen et al. 11

[2014] published a review of various fluorescent probes used for hydrazine detection. The use of fluorescent probes allows detection of hydrazine in the ng.L range. -1 The lower end of the range of hydrazine concentrations in water can be achieved. The best sensitivity achieved is 35 ng.L in water. -1 [ 12 ], 60ng.L -1 [ 13 ], 280ng.L -1 [ 14 ] and 300 ng.L -1 [ 15 However, the main drawback of the fluorescent probes is their availability. In particular, none of the proposed probes are currently commercially available. Furthermore, the authors do not mention any stability tests for the adducts that are formed.

[0021] Another method is based on the reducing properties of hydrazine in acidic medium. Afkhami et al. 16

[2009] proposed a method for the indirect detection of hydrazine in solution based on the inhibition of the redox reaction between bromate ions and hydrochloric acid. In acidic media, bromate ions (BrO 3 - ) is a chloride ion (Cl - ) by Br 2 The chlorine and bromine are then measured by the decolorization of methyl orange, which absorbs at 525 nm. The presence of hydrazine has the effect of inhibiting the decolorization of methyl orange. Specifically, hydrazine is a strong reducing agent and reacts rapidly with chlorine and bromine to Cl. - and Br - ions are formed. The rate of decolorization is reduced in the presence of hydrazine. This method is-1 Detection limits of 9.6 to 1024 μg.L -1 This allows for linear discrimination of hydrazine.

[0022] Methyl orange was used in combination with Victoria Blue 4R to obtain similar sensitivity. 17 However, there is an interference: the hydrazine interferent NH 3 is Cl 2 and Br 2 , which makes the method non-selective.

[0023] Hydrazine also reacts with the chloroauric acid molecule (HAuCl 4 ) is reduced to induce the formation of gold nanoparticles AuNPs, which are stable in the presence of sulfamic acid and whose resonant plasmons can be detected in the visible range. 18

[2013] utilized this method by following the growth of AuNPs, whose size increased with hydrazine concentration. The initially colorless solution turned red and then blue at higher hydrazine concentrations. Monitoring the absorbance at 540 nm revealed that 2.72 μg.L -1 Detection limits of 3.2 to 8096 μg.L -1 To improve sensitivity, various teams have modified the method by replacing sulfamic acid with sodium dodecyl sulfate [ 19 ], dipicolinic acid [ 20 ] or sodium citrate [ 21 The latter offers advantageous sensitivity, with a detection limit of 3.2 × 10 -5 μg.L -1 However, it is only 3.2 × 10 -4 to 3.2 μg.L -1 It has a very limited measurement range ranging from

[0024] Tashkhourian et al. 22

[2013] employed the same principle and proposed the detection of hydrazine using the plasmon resonance of silver nanoparticles at 415 nm. Hydrazine can be detected by the ion exchange reaction of AgNO in the presence of stabilizers such as polyvinylpyrrolidone or dodecyldimethylammonium chloride. 3 to silver nanoparticles. This method allows the individual detection of hydrazine, phenylhydrazine and isoniazid, with detection limits of 3.84 μg L each. -1 (hydrazine), 13 μg.L -1 (phenylhydrazine) and 16.4 μg.L -1 (isoniazid), but is not selective.

[0025] Of all the listed methods for measuring hydrazine in water, only the p-dimethylaminobenzaldehyde (pDMAB) method is hydrazine selective and can be used at room temperature within the target hydrazine concentration range. This method is used industrially as an adjunct, but the protocol indicates a measurement time range of 16 hours, after which the colored product benzalazine decomposes. Therefore, it is not possible to use this method for measurements with a 24-hour delay. Furthermore, in this method, the reaction product, when formed, absorbs in the UV in a range where the absorbance is saturated by the absorbance of pDMAB alone, so that NH 2 It is not possible to detect and quantitate interfering substances such as EtOH or morpholine.

[0026] Detection of hydrazine in air Methods for measuring hydrazine in air are specifically targeted at concentrations between 1.3 and 264 μg.m -3 In the target range (i.e. 1 to 200 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. 23]. 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.[ 24, 25 ]. With this method it is possible to detect hydrazine at 30 ppb within 15 minutes of sampling. A variation 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.[ 26 This assay method provides a N concentration of 0.017 ppb. 2 H 4 These two methods are not capable of directly measuring NH3 at high concentrations, which are 50 to 100 times higher than the hydrazine concentration. 3 or other amine interferences are unknown.

[0027] 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. 27, 28 ]. 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 [ 29] and CHEMSEE 30 They allow the estimation of the hydrazine and monomethylhydrazine content in the air in the range of 0.025 to 1.2 ppm.

[0028] Patent US00 / 5719061A[ 31 In

[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 order, 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.

[0029] For accurate measurements, several commercial devices are available: a portable electrochemical detector, model 4180-100b from Interscan; 32 ] allows detection of hydrazine in the lower range of 0 to 100 ppb in less than 1 second, with a detection limit of 10 ppb. However, the sensor detects NH 3 , NO x This method is non-selective since it also detects CO and other organic amines.

[0030] High sensitivity can also be obtained using devices equipped with a photoionization detector (PID), such as the ppbRAE 3000 from RAE. 33 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.

[0031] 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 be selective in terms of the choice of carrier gas

[38] . When a radioactive source is used, the IMS (e.g. the SABRE 4000 [ 34 ] or Environics ChemPro100i[ 35 ]Portable detectors) must be under the control of personnel with good radiation protection. This technology 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 [ 36 ] or LCD 3.3[ from Smiths Detection 37 ] etc.

[0032] The prior art in hydrazine determination shows that only the currently existing simple method using pDMAB as a reagent can be used in water bodies with good selectivity and sensitivity. However, benzalanine formed in solution is unstable after 16 hours and measurements cannot be made after a 24-hour delay. For the measurement of hydrazine in air, the INRS (Institut National de Recherche et de Securite for the prevention of work-related accidents and occupational diseases) uses benzaldehyde. This method requires an adsorption step followed by a desorption step before analysis, which are difficult to perform on site. Furthermore, this method requires the detection of high concentrations of NH, either in water or in air. 3 , ethanolamine or morpholine gas interference is unknown. [Prior art documents] [Patent documents]

[0033] [Patent Document 1] Patent US00 / 5719061A Summary of the Invention [Problem to be solved by the invention]

[0034] Thus, there is a real need for a hydrazine-selective method for detecting and optionally quantifying hydrazine that may be used in bodies of water and air, that is compatible with the potential presence of high concentrations of interfering substances, that can be easily performed in the field, and that allows measurements to be made with a maximum delay of at least 24 hours.

[0035] The method according to the present invention addresses these problems. [Means for solving the problem]

[0036] A first subject of the present invention is a method for detecting at least one amine type compound using a reagent composition comprising a mixture of 4-(dimethylamino)cinnamaldehyde and polystyrene sulfonic acid, the amine-type compound is selected from hydrazine, ethanolamine, and morpholine; The method further comprising: a) mixing the sample to be analyzed with the reagent composition to obtain a mixture of the sample to be analyzed and the reagent composition; b) detecting said amine-type compound in a mixture of a sample to be analyzed and said reagent composition; Including, This is the method.

[0037] Another subject of the invention is a reagent composition comprising a mixture of 4-(dimethylamino)cinnamaldehyde and polystyrene sulfonic acid.

[0038] The subject of the present invention is also the use of a reagent composition comprising a mixture of 4-(dimethylamino)cinnamaldehyde and polystyrene sulfonic acid for the detection of at least one amine type compound, said amine type compound being selected from hydrazine, ethanolamine and morpholine.

[0039] Another subject of the invention is a kit for preparing a reagent composition according to the invention, - a first container containing 4-(dimethylamino)cinnamaldehyde; - a second container containing an aqueous solution of polystyrene sulfonic acid; The kit comprises:

[0040] Other features, details and advantages will become apparent upon reading the following detailed description and examining the accompanying drawings. [Brief description of the drawings]

[0041] [Figure 1]FIG. 1 shows a scheme of the reaction between two molecules of N2H4 and DMACA with the formation of the colored product 2DMACA-N2H4, which absorbs in the visible range. [Diagram 2] Figure 1 shows difference spectra obtained at different times showing the evolution of the 2DMACA-N2H4 complex towards its protonated form with the presence of an isosbestic point at 553 nm. The conditions applied were: DMACA 5x10-3M + PSS 9.2gL-1 + N2H4 5.5x10-6M, quartz cell with 1 cm path length. [Diagram 3] FIG. 1 shows a scheme of the reaction between NH2EtOH and DMACA with the formation of a NH2EtOH-DMACA complex that absorbs at 474 nm. [Figure 4] Figure 1 shows the difference spectrum of the reaction between DMACA and NH2EtOH as a function of time. The conditions applied were: DMACA 5x10-3 M + PSS 9.2 g L-1 + NH2EtOH 6.24x10-4 M, quartz cell with 1 cm path length. [Diagram 5] FIG. 1 shows a scheme of the reaction between morpholine and DMACA, involving the formation of a morpholine-DMACA complex. [Figure 6] Figure 1 shows the evolution of the spectrum of the morpholine-DMACA complex as a function of time. The conditions applied were: DMACA 5x10-3 M + PSS 9.2 g L-1 + morpholine 6.24x10-4 M, quartz cell with 1 cm path length. [Figure 7] Figure 1 shows a calibration curve of the variation of absorbance of the 2DMACA-N2H4 adduct as a function of [N2H4] concentration from 5x10-7 to 5.5x10-6 M. The conditions applied were: [DMACA] = 5x10-3 M, [PSS] = 9.2 g L-1, i.e. r = [H+] / [DMACA] = 10, 1 cm path length, at 553 nm (5 min, isosbestic point), 474 nm for 24 h, and 487 nm for 1 h. [Figure 8]Figure 1 shows a calibration curve of the variation of absorbance at 474 nm of the DMACA-NH2EtOH adduct as a function of NH2EtOH concentration from 1x10-4 to 2x10-3 M at 24 hours. The following conditions apply: 1 cm path length. [DMACA]=5x10-3 M, [PSS]=9.2 g L-1, i.e. r=[H+] / [DMACA]=10. [Figure 9] Figure 1 shows a calibration curve of the variation of absorbance at 487 nm of the DMACA-morpholine adduct at 1 hour as a function of morpholine concentration from 5 x 10-5 to 6.24 x 10-4 M at 1 hour. The following conditions apply: 1 cm path length. [DMACA] = 5 x 10-3 M, [PSS] = 9.2 g L-1, i.e. r = [H+] / [DMACA] = 10. [Figure 10] FIG. 1 shows N2H4 measurements in the presence of interfering substances (NH3+NH2EtOH or NH3+morpholine) at an industrial site and a comparison of DMACA / PSS analytical method (r=10) with pDMAB (p-dimethylaminobenzaldehyde or pDMABA) analytical method and amperometric measurements. [Figure 11] Figure 1. Reproducibility test of low N2H4 content measurements. The applied conditions were: 60 min sampling at a flow rate of 1 L.min-1 with sparging in 50 mL of reagent solution (DMACA / PSS, r=10); P=101325 Pa; R=8.3144621 JK-1·mol-1; T=295 Kelvin. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0042] The subject of the present invention is a method for detecting at least one amine-type compound in an analyte sample using a reagent composition comprising a mixture of 4-(dimethylamino)cinnamaldehyde and polystyrene sulfonic acid, said amine-type compound being selected from hydrazine, ethanolamine, ammonia and morpholine, The method further comprising: a) mixing the sample to be analyzed with the reagent composition to obtain a mixture of the sample to be analyzed and the reagent composition; b) detecting said amine-type compound in a mixture of a sample to be analyzed and said reagent composition; The method includes:

[0043] 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 sample, said amine type compound being selected from hydrazine, ethanolamine 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 sample, using a reagent composition comprising a mixture of 4-(dimethylamino)cinnamaldehyde and polystyrene sulfonic acid, comprising: the amine-type compound is selected from hydrazine, ethanolamine, and morpholine; The method further comprising: a) mixing the sample to be analyzed with the reagent composition to obtain a mixture of the sample to be analyzed and the reagent composition; b) detecting and quantifying said amine-type compound in a mixture of a sample to be analyzed and said reagent composition; The present invention relates to a method comprising the steps of:

[0044] Advantageously, the method according to the invention allows the detection and even quantification of hydrazine despite the presence of interfering substances in the sample to be analyzed, such as ammonia, ethanolamine or morpholine. The method according to the invention in this particular embodiment therefore offers a real advantage, since it allows these amine-type compounds to be detected and quantified in a single step.

[0045] In the context of the present invention, the term "quantification" refers to the determination of the concentration of a compound in an analyzed sample.

[0046] The method according to the invention can be advantageously applied to liquid or gaseous samples or aerosols. The method according to the invention remains identical regardless of whether the sample to be analyzed is a liquid, a gas or an aerosol, only the method of collecting the sample to be analyzed may differ.

[0047] For the purposes of the present invention, the term "liquid sample" means a sample in the form of a solution or suspension. For the purposes of the present invention, the term "aerosol" means a suspension of solid or, more generally, liquid particles in air or gas.

[0048] Step b) of the detection or detection and quantification of the method according to the invention can in particular be carried out by measuring the absorbance of a mixture consisting of the sample to be analysed and said reagent composition as a function of time. This step b) is therefore carried out in solution.

[0049] The advantages of the method according to the invention compared to currently available methods, particularly those using pDMAB reagents, are numerous:

[0050] - In particular, 2DMACA-N, which has an absorption spectrum in the visible range from 460 to 620 nm 2 H 4 Through measurement of the absorbance of the adduct as a function of time, hydrazine (N 2 H 4 ) can be selectively detected and optionally quantified. Such detection and quantification is possible and remains reliable despite the presence of high interferent concentrations relative to the hydrazine concentration in the sample. Thus, the interferent concentrations may be more than 200 times higher than the hydrazine concentration without compromising the effectiveness of the hydrazine detection method.

[0051] - In the case of time-dependent absorbance measurement of hydrazine in water (also known as colorimetric measurement), this is easily, quickly and instantly achieved by collecting a specific volume of the analyte solution and mixing it with a reagent solution.

[0052] - 2DMACA-N 2 H 4In the case of measurements of absorbance as a function of time, due to the presence of a stable isosbestic point in the absorption spectrum of the adduct, the hydrazine measurement via the absorbance of the adduct complex at this point can be immediate, or can be performed after a delay of up to 3 days, since the inventors have demonstrated that the isosbestic point is stable for at least 3 days. Thus, the experimenter can perform an immediate measurement of the hydrazine concentration at, for example, 5 minutes, and have, for example, 3 days to check later if the experimenter so desires. The isosbestic point corresponds to the wavelength at which the absorbance is constant during the chemical reaction. Thus, in the present case, the chemical reaction is carried out by reacting the starting material (here 2DMACA-N 2 H 4 ) and the final product (protonated 2DMACA-N 2 H 4 ) which have the same absorption coefficient at this wavelength.

[0053] - The measurement of hydrazine in air is carried out by collecting the air to be analysed at a constant rate and sparging it into a reagent solution for a specific period of time, using the same analytical method as if the sample were a liquid. Due to its high solubility, the N contained in the collected air is 2 H 4 The gas quickly dissolves in the reagent solution and reacts with 2DMACA-N at the isosbestic point. 2 H 4 Based on the absorbance of the adduct, N 2 H 4 A measurement is taken.

[0054] - This is especially true for the absorption spectrum of 2DMACA-N 2 H 4 The adduct DMACA-NH 2 By measuring the absorbance of EtOH or DMACA-morpholine as a function of time, the interfering substance ethanolamine (NH 2 EtOH) or morpholine concentration can be measured.

[0055] - The determination of ethanolamine or morpholine present in the air can also be carried out by its dissolution in a reagent solution and the colored DMACA-NH2 This is possible via determination of the absorbance as a function of time of the EtOH or DMACA-morpholine complex.

[0056] The analytical method allows the determination of the content of hydrazine and interfering substances having primary or secondary amine functions by measuring the absorbance as a function of time, comprising the steps of: 2 H 4 Adduct complexes, as well as the interfering substance ethanolamine (NH 2 EtOH) and the absorption spectra of the DMACA adduct with morpholine.

[0057] Two interfering substances, NH 2 EtOH+NH 3 or morpholine + NH 3 This method for determining hydrazine in the presence of advantageously comprises a series of steps as detailed below.

[0058] In aqueous solution, hydrazine (N 2 H 4 The reaction between 4-(dimethylamino)cinnamaldehyde (DMACA) and red 2DMACA-N 2 H 4 This results in the formation of an addition complex ([Figure 1] and [Figure 2]).

[0059] The presence of polystyrene sulfonic acid protonates DMACA and N 2 H 4 is necessary to promote the addition of N to DMACA. 2 H 4 Protonation can also occur in acidic media. 2 H 4 It inhibits the formation of the adduct. 2 H 4 The amount of acid required for the reaction between DMACA and N 2 H 4 It must be chosen to minimize protonation.

[0060] The process according to the invention is therefore advantageously carried out with a ratio r between the concentration of polystyrenesulfonic acid and the concentration of 4-(dimethylamino)cinnamaldehyde of between 1 and 20, preferably between 2 and 15 and even more preferentially 10.

[0061] This ratio is calculated from the molar concentration of polystyrene sulfonic acid 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.

[0062] Different amounts of PSS acid, 1.84 - 3.68 - 5.98 and 9.2gL -1 , i.e. 2 - 4 - 6.5 and the ratio r = [H + Tests performed on [DMACA] showed that the adduct 2DMACA-N 2 H 4 There is further evolution of the product absorbing at 558 nm to its protonated form absorbing at 535 nm, with a stable isosbestic point observed for 3 days. The wavelength corresponding to the isosbestic point varies with the ratio r and thus ranges from 553 nm (r=10) to 538 nm (r=2).

[0063] 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.

[0064] DMACA is also a NH 2 It reacts with other amines such as EtOH to produce NH 2 Generate EtOH-DMACA conjugate ([Figure 3] and [Figure 4]).

[0065] Figure 4 shows the NH 2 The formation of the EtOH-DMACA complex and its evolution over time are shown. The maximum absorption of the complex is observed for 2DMACA-N 2 H 4 474 nm, in a region where the complex and its protonated form do not actually absorb. 2 The reaction between EtOH, DMACA and N 2 H 4 The reaction is much slower than that between NH 2 To determine the EtOH concentration, the time factor is taken into account in the calibration curve.

[0066] In the presence of morpholine, the morpholine-DMACA adduct is formed and absorbs at 487 nm (Figure 5). The rate of formation of morpholine-DMACA is faster than that of ethanolamine-DMACA. The absorbance at 487 nm reaches a plateau after 1 h (Figure 6).

[0067] According to a particular embodiment, the detection or detection and quantification method according to the invention may be carried out according to the following steps: 1. Preparation of a reagent solution by mixing DMACA and PSS in water; 2. At a given wavelength, e.g., the isosbestic point at 553 nm, 487 nm (t=1 hr) and 474 nm (t=24 hr) of 2DMACA-N 2 H 4 N from the absorbance of the adduct 2 H 4 Establishing a calibration curve, 3. Establishment of calibration curves of other amine type compounds (interfering substances) at given wavelengths, e.g. 474 nm for ethanolamine and 487 nm for morpholine; 4. Preparing the sample for analysis by mixing the reagent solution and the collected sample; 5. Measuring the absorbance of the analyte sample as a function of time (e.g., 5 minutes, 1 hour, and 24 hours); 6. From the spectrum of absorbance as a function of time for the sample being analyzed and the equation of the calibration curve obtained previously, N 2 H 4 and calculation of concentrations of other amine-type compounds (interfering substances).

[0068] According to a particular embodiment, N 2 H 4 and N.H. 2 The method for detecting and quantifying EtOH (or morpholine) can be carried out using the following steps:

[0069] 1. Prepare a reagent solution by mixing the specified amounts of DMACA and PSS in water. In this way, known final concentrations of DMACA and PSS, and a similarly predefined ratio of these concentrations, r=[H + A reagent stock solution having a concentration of 0.01% is obtained.

[0070] 2. Isosbestic points at 553 nm, 487 nm (t = 1 h) and 474 nm (t = 24 h) of 2DMACA-N 2 H 4 N from the absorbance of the adduct 2 H 4 Establishing the calibration curve. 5×10 -7 From 5.5 × 10 -6 mol.L-1 Various concentrations of N in the range 2 H 4 Add a volume x (e.g., 5 mL) of a solution containing N 2 H 4 A calibration curve is prepared. The resulting solutions are examined by UV-visible spectroscopy using a quartz cell with a 1 cm path length for 5 minutes to 24 hours.

[0071] Different wavelengths (Figure 7): 553 nm (isobestic point), 474 nm (NH 2 A calibration curve is established at 487 nm (EtOH absorption peak) and 1 h at 487 nm (morpholine absorption peak). 2 H 4 Plotting the line corresponding to the time evolution of absorbance as a function of concentration gives, by linear regression, the following equation: - At the isosbestic point, Abs (at 553 nm) 2 H 4 ))=A[N 2 H 4 ] - Abs (474 ​​nm, 24 hours (2DMACA-N 2 H 4 ))=A 1 [N 2 H 4 ] - Abs (487 nm, 1 h (2DMACA-N 2 H 4 ))=A 2 [N 2 H 4 ].

[0072] 3. NH 2 Establishment of calibration curves for EtOH or morpholine interfering substances 3.a. DMACA-NH at the absorption peak at 474 nm 2 NH from absorbance measurements of EtOH complexes 2 Establishment of calibration curve for EtOH interferents. 1×10 -4 From 2 × 10 -3 mol.L-1 Various concentrations of NH in the range 2 Adding a volume x (e.g., 5 mL) of a solution containing EtOH to the same volume x of the reagent solution prepared in step 1, yields NH 2 Create an EtOH calibration curve.

[0073] The DMACA-NH concentration was measured by measuring the absorbance at 474 nm in a quartz cell with a path length of 1 cm for 24 h. 2 Prepare a calibration curve for the EtOH adduct. 2 Plotting the line corresponding to the evolution of absorbance over 24 hours as a function of EtOH concentration gives, by linear regression, the following equation: Abs (474 ​​nm and (DMACA-NH 2 EtOH))=B[NH 2 EtOH] (Figure 8).

[0074] 3.b. Establishment of a calibration curve for morpholine interferents from absorbance measurements of the DMACA-morpholine complex at the absorption peak at 487 nm. 5×10 -5 From 6.24 × 10 -4 mol.L -1 Create a morpholine calibration curve by adding a volume x (e.g., 5 mL) of solution containing various concentrations of morpholine in the range of 0.01 to the same volume x of the reagent solution prepared in step 1.

[0075] A calibration curve for the DMACA-morpholine adduct is constructed by measuring the absorbance at 487 nm for 1 hour using a quartz cell with a path length of 1 cm. The line corresponding to the evolution of the absorbance in 1 hour as a function of the morpholine concentration is plotted, giving, by linear regression, the following equation: Abs((DMACA-morpholine))=C[morpholine] at 487 nm and 1 h (FIG. 9).

[0076] 4. Sample Collection N 2 H 4 and N.H. 2 EtOH (or N 2 H4 Collection of the analyte sample containing morpholine and morpholine is carried out as follows:

[0077] - In a volumetric flask, a volume x (for example 5 mL) of the reagent solution is introduced, followed by the same volume x of the sample to be analyzed. Regarding the actual concentration of the analyte thus diluted 2-fold in this mixture, whose absorbance is measured, this dilution by a factor of 2 must be taken into account when calculating the concentration.

[0078] - Interfering substances are NH 2 In the case of EtOH, collect the absorption spectra of the mixture consisting of the reagent solution and the sample to be analyzed from 400 to 700 nm at 5 minutes and 24 hours.

[0079] - If the interfering substance is morpholine, collect the absorption spectra of the mixture consisting of the reagent solution and the sample to be analyzed from 400 to 700 nm at 5 minutes and 1 hour.

[0080] 5. Calculation 5.a.N 2 H 4 and N.H. 2 N in mixtures containing EtOH (or morpholine) 2 H 4 The concentration calculation is as follows:

[0081] 2DMACA-N 2 H 4 The absorbance (Abs) of the adduct was determined by 2 H 4 and protonated 2DMACA-N 2 H 4 The isosbestic point of the compound is measured at 553 nm for r=10.

[0082] The previously prepared calibration curve Abs (at 553 nm) at the isosbestic points was calculated according to the following equation: 2 H 4 ))=A[N 2 H 4 ] to calculate the mol.L of sample. -1 N in2 H 4 Derive the concentration.

[0083]

number

[0084] 5.b. Interfering substance is NH 2 If EtOH, N 2 H 4 and N.H. 2 NH in mixtures containing EtOH 2 The calculation of EtOH concentration is as follows:

[0085] N obtained in 5.a. 2 H 4 From the concentration, 2DMACA-N at 474 nm and 24 hours 2 H 4 The absorbance of the calibration curve Abs (474 ​​nm, 2DMACA-N 2 H 4 ))=A1[N 2 H 4 ] is obtained from.

[0086] DMACA-NHN in the mixture at 24 h 2 H 4 Derive the absorbance of EtOH: Abs (DMACA-NHN at 474 nm) 2 H 4 (EtOH)) = Abs((mixture) at 474 nm) - Abs((2DMACA-N 2 H 4 ))

[0087] The calibration curve Abs(DMACA-NH 2 EtOH)=B[NH 2 EtOH] to mol.L of sample -1 NH in 2 Derive EtOH concentration: (Figure 8):

[0088]

number

[0089] 5.c. If the interfering substance is morpholine, N 2 H 4 and the calculation of the morpholine concentration in a mixture containing morpholine is as follows:

[0090] N obtained in 5.a. 2 H 4 From the concentration, 2DMACA-N at 487 nm in 1 hour 2 H 4 The absorbance of the calibration curve Abs (487 nm, 1 h) (2DMACA-N 2 H 4 ))=A 2 [N 2 H 4 ] (Figure 7).

[0091] Derive the absorbance of DMACA-morpholine in the mixture at 1 hour: Abs(DMACA-morpholine) at 487 nm) = Abs(mixture) at 487 nm) - Abs(2DMACA-N at 487 nm, 1 h 2 H 4 ))

[0092] From the calibration curve Abs(DMACA-morpholine)=C[morpholine] obtained in 3.b., the mol.L -1 Derive the morpholine concentration at (Figure 9):

[0093]

number

[0094] According to another particular embodiment, when the sample to be analyzed is a gaseous sample, the N 2 H 4 and N.H. 2The method steps for detecting and quantifying EtOH (or morpholine) may be the same as those described above for the liquid sample to be analyzed. Nevertheless, gaseous N 2 H 4 and N.H. 2 The method for detecting and quantifying EtOH (or morpholine) requires an additional step compared to the same method applied to samples in aqueous solution, which corresponds to collecting the ambient air to be analyzed and sparging it into the mixture of liquid reagents.

[0095] Thus, the sampling step may be performed as follows: the air to be analyzed is passed through a bubbler filled with a known volume (e.g., 50 mL) of a mixture of the reagents DMACA and PSS at a known flow rate (e.g., 1 L.min -1 ) After 1 hour, collect the solution for spectrophotometric analysis.

[0096] The interfering substance is then NH 2 If the interfering substance is EtOH, collect spectra of the mixture from 400 to 700 nm at 5 minutes and after 24 hours. If the interfering substance is morpholine, collect spectra of the mixture from 400 to 700 nm at 5 minutes and after 1 hour.

[0097] Subsequent calculation steps are based on the amount of N dissolved in the reagent. 2 H 4 and N.H. 2 To find the concentration of these analytes in a gas mixture, a 1 L.min -1 The total volume of gas pumped in one hour (in a stream of 1000 sq. m) must be taken into account.

[0098] 5'.a.N 2 H 4 and N.H. 2 N in mixtures containing EtOH (or morpholine) 2 H 4 The concentration of is calculated as follows:

[0099] 2DMACA-N2 H 4 The absorbance (Abs) of the adduct was determined by 2 H 4 and protonated 2DMACA-N 2 H 4 The isosbestic point of the complex is determined at 553 nm for r=10.

[0100] The previously prepared calibration curve Abs (at 553 nm) at the isosbestic points was calculated according to the following equation: 2 H 4 ))=A[N 2 H 4 ] to calculate the mol.L of sample. -1 N in 2 H 4 Derive the cardinality:

[0101]

number

[0102] 5'.b.N 2 H 4 and N.H. 2 NH in mixtures containing EtOH 2 The calculation of EtOH concentration is as follows:

[0103] N obtained in 5'.a. 2 H 4 From the concentration, 2DMACA-N at 474 nm and 24 hours 2 H 4 The absorbance of the calibration curve Abs (474 ​​nm, 1 h) (DMACA-N 2 H 4 ))=A 1 [N 2 H 4 ] is obtained from.

[0104] DMACA-NH in the mixture at 24 h 2 The absorbance of EtOH is derived from: Abs (DMACA-NH 2(EtOH)) = Abs((mixture) at 474 nm) - Abs((2DMACA-N 2 H 4 ))

[0105] Mol.L of sample -1 NH in 2 The EtOH concentration was calculated using the calibration curve Abs (DMACA-NH at 474 nm) obtained in 3.a. 2 EtOH))=B[NH 2 EtOH]:

[0106]

number

[0107] 5'.c. If the interfering substance is morpholine, N 2 H 4 and N.H. 2 The calculation of the morpholine concentration in the mixture containing EtOH is as follows:

[0108] N obtained in 5'.a. 2 H 4 From the concentration, 2DMACA-N at 487 nm in 1 hour 2 H 4 The absorbance of the calibration curve Abs (at 487 nm (2DMACA-N 2 H 4 ))=A 2 [N 2 H 4 ] is obtained from.

[0109] Derive the absorbance of DMACA-morpholine in the mixture at 1 hour: Abs(DMACA-morpholine) at 487 nm) = Abs(mixture) at 487 nm) - Abs(2DMACA-N at 487 nm) 2 H 4 ))

[0110] Mol.L of sample -1The morpholine concentration in is derived from the calibration curve Abs((DMACA-morpholine) at 487 nm)=C[morpholine] obtained in 3.b.:

[0111]

number

[0112] 5'.d. N in gas mixtures at ppb 2 H 4 (or NH 2 The EtOH or morpholine) content is derived according to the following equation:

[0113]

number

[0114] Where: i=N 2 H 4 , N.H. 2 EtOH or morpholine Number of moles of i = [i](mol.L -1 )*V (V = volume of reagent solution = e.g. 50 x 10 -3 L)

[0115]

number

[0116] (D = air flow rate = e.g. 1L.min -1 , t = sampling time = 1 hour, V m = Molar volume of air = 24.21 L.mol at 22°C -1 )

[0117] In addition to the detection method previously defined, the subject of the present invention is also a reagent composition comprising a mixture of 4-(dimethylamino)cinnamaldehyde and polystyrene sulfonic acid, which, in a medium comprising an amine type compound, such as hydrazine, ethanolamine or morpholine, advantageously allows a reaction between the amine type compound and 4-(dimethylamino)cinnamaldehyde, which reaction is catalyzed by polystyrene sulfonic acid and leads to the formation of an addition complex with absorbance characteristics in the UV-visible range.

[0118] The reaction between amine type compounds and 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. Firstly, this acid is capable of reacting with 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 makes it possible to adjust the acidity of the solution to catalyze the reaction between

[0119] Furthermore, low molecular weight inorganic and organic acids have the disadvantage that acid vapors can be released during the process of sparging the gaseous mixture to be analyzed, and thus the acid is prone to evaporation during sparging, a drawback that does not exist in the case of acids derived from polymers such as polystyrene sulfonic acid, since these acids are not volatile.

[0120] One of the main advantages of this reagent composition is its stability over time, which can be up to at least one week. This stability was demonstrated by the inventors by measuring the absorbance spectrum of the reagent composition up to one week after its preparation. The spectrum obtained was identical to the spectrum obtained immediately after the preparation of the composition. The composition is thus prepared and can be stored for this period without compromising its effectiveness in the method according to the invention. This feature advantageously eliminates the constraint of having to prepare the reagent composition before each sample analysis process.

[0121] According to a particular embodiment, the composition according to the invention is characterized by a particular ratio r of the concentrations of 4-(dimethylamino)cinnamaldehyde and polystyrenesulfonic acid, this ratio ranging from 1 to 20, preferably from 2 to 15 and even more preferentially being 10.

[0122] A subject of the present invention is also the use of a reagent composition according to the invention for the detection of at least one amine-type compound, said amine-type compound being chosen from hydrazine, ethanolamine and morpholine.

[0123] According to a particular embodiment, the present invention also relates to the use of the reagent composition according to the invention for the determination of at least one amine type compound, said amine type compound being selected from hydrazine, ethanolamine and morpholine.

[0124] The use according to the invention may advantageously be applied to liquid or gaseous samples or to aerosols.

[0125] Another subject of the invention is a kit for preparing a reagent composition according to the invention, - a first container containing 4-(dimethylamino)cinnamaldehyde; - a second container containing an aqueous solution of polystyrene sulfonic acid; The kit according to the invention advantageously enables the reagent composition according to the invention to be prepared for its use in the method according to the invention. This preparation is particularly simple and can be carried out quickly, since it only requires mixing two compounds in water. EXAMPLES

[0126] Compounds used - 4-(Dimethylamino)cinnamaldehyde (DMACA, Sigma-Aldrich, Ref: D4506-5g, Batch: BCBX0916, CAS: 6203-18-5, Purity ≥ 98%, Molar mass = 175.23 g / mol); - Polystyrene sulfonic acid 18% in water (PSS, Sigma-Aldrich, Ref: 561223-100G, Batch: MKBV7207V, CAS: 28210-41-5, molar mass about 75000 g / mol, density = 1.11 g / mL at 25 °C), - 50-60% hydrazine hydrate in water (N 2 H 4 , Sigma-Aldrich, Ref: 225819-100mL, Batch: BCCC1556, CAS: 10217-52-4, Molar mass = 32.05g / mol, Density = 1.029g / mL at 25°C), - Ethanolamine (NH 2 EtOH, Sigma-Aldrich, Ref: 398136-500mL, Batch: STBJ4500, CAS: 141-43-5, Purity ≥ 98%, Molar mass = 61.08g / mol, Density = 1.012g / mL at 25°C); - morpholine (Sigma-Aldrich, Ref: 252360-100mL, batch: MCKM6935, CAS: 110-91-8, purity ≥ 99%, molar mass = 87.012g / mol, density = 0.996g / mL at 25°C), - 28% ammonia solution (NH 3 , VWR, Ref:21182.94, Batch:15J260522, CAS:1336-21-6, Molar mass=17.03g / mol, Density d=0.89g / mL), - Milli-Q® deionized water.

[0127] Example 1 [DMACA]=5×10 -3 M, [PSS] = 9.2 gL -1 (i.e. r = [H + ] / [DMACA]=10) in aqueous solution. 2 H 4 and N.H. 2 Protocol for Assaying EtOH (or Morpholine) N in water 2 H 4 and N.H. 2The EtOH (or morpholine) assay is performed as follows:

[0128] 1) Preparation of the reagent solution: 87.62 mg of DMACA and 4.604 mL of 18% PSS are placed in a 50 mL volumetric flask containing 25 mL of water. Water is added up to the graduation line, and the solution is then sonicated in an ultrasonic bath for 30 minutes to completely dissolve the DMACA. -1 A reagent stock solution with a final DMACA and PSS concentration of r = [H + ] / [DMACA]=10.

[0129] 2) Isosbestic points at 553 nm, 487 nm (t = 1 h) and 474 nm (t = 24 h) of 2DMACA-N 2 H 4 N from the absorbance of the adduct 2 H 4 Establishing the calibration curve (r = [H + ] / [DMACA]=10) a) 5 × 10 -7 From 5.5 × 10 -6 mol.L -1 Various concentrations of N in the range 2 H 4 Add 5 mL of a solution containing N to the 5 mL of reagent solution prepared in step 1). 2 H 4 A calibration curve is made. The solutions are tested by UV-Visible spectroscopy using a quartz cell with a 1 cm path length for 5 min to 24 h. Different wavelengths: 553 nm (isobestic point), 474 nm (NH 2 Establish a calibration curve at 487 nm (EtOH absorption peak) and 487 nm (morpholine absorption peak) at 1 h (Figure 7): - At the isosbestic point, Abs(553nm)=Ax=29110[N 2 H 4 ]. - At 474 nm and 24 hours, Abs(474 nm, 24 hours) = A 1 x=7080[N 2 H 4 ]. - At 487 nm and 1 hour, Abs(487 nm, 1 hour) = A 2 x=7810[N 2 H 4 ].

[0130] 3)NH 2 Establishment of calibration curves for EtOH or morpholine interfering substances a) DMACA-NH at the absorption peak at 474 nm at 24 h 2 NH from absorbance measurements of EtOH complexes 2 Establishment of calibration curve for EtOH interferents. 1×10 -4 From 2 × 10 -3 mol.L -1 Various concentrations of NH in the range 2 NH was prepared by adding 5 mL of a solution containing EtOH to the 5 mL of the reagent solution prepared in step 1). 2 Prepare a calibration curve for EtOH. DMACA-NH by measuring the absorbance at 474 nm over 24 h using a quartz cell with a path length of 1 cm. 2 A calibration curve of EtOH adduct is prepared. Abs(DMACA-NH) at 474 nm and 24 h 2 EtOH) = Bx = 117 [NH 2 EtOH] ([Figure 8]).

[0131] b) Calibration curve for morpholine interferents based on absorbance measurements of the DMACA-morpholine complex at the absorption peak at 487 nm. 5×10 -5 From 6.24 × 10 -4 mol.L -1 Prepare a morpholine calibration curve by adding 5 mL of a solution containing various concentrations of morpholine in the range of 0.1 to 5 mL of the reagent solution prepared in step 1). Prepare a calibration curve for DMACA-morpholine adduct by measuring the absorbance at 487 nm for 1 hour using a quartz cell with a 1 cm path length. Abs(DMACA-morpholine) = Cx = 488 [morpholine] at 487 nm and 1 h (Figure 9).

[0132] 4) Sampling N 2 H 4 and N.H. 2 EtOH (or N 2 H 4 The analyte solution containing dimethylformamide (DMSO) and morpholine is collected as follows: - 5 mL of the reagent solution is introduced into a 10 mL volumetric flask, followed by 5 mL of the sample to be analyzed. The actual concentration of the analyte is diluted 2-fold in the mixture, so this dilution must be taken into account when calculating the concentration. - Interfering substances are NH 2 In the case of EtOH, collect the absorption spectra of the mixture from 400 to 700 nm at 5 minutes and at 24 hours. - If the interfering substance is morpholine, collect the absorption spectra of the mixture from 400 to 700 nm at 5 minutes and at 1 hour.

[0133] 5) Calculation a)N 2 H 4 and N.H. 2 N in mixtures containing EtOH (or morpholine) 2 H 4 The concentration of is calculated as follows: - 2DMACA-N at isosbestic point 553 nm 2 H 4 Absorbance of the adduct (Abs). - The previously generated calibration curve at the isosbestic point according to the following equation: Abs(553 nm) = Ax = 29110[N 2 H 4 ] to calculate the mol.L of sample. -1 N in 2 H 4 Derive the concentration.

[0134]

number

[0135] b) The interfering substance is NH 2 If EtOH, N2 H 4 and N.H. 2 NH in mixtures containing EtOH 2 The calculation of EtOH concentration is as follows: - N obtained in 5)a) 2 H 4 From the concentration, 2DMACA-N at 474 nm and 24 hours 2 H 4 The absorbance of Abs(2DMACA-N) at 474 nm for 24 hours was calculated based on the calibration curve obtained in 2)a). 2 H 4 )=7080[N 2 H 4 ] is obtained from. - DMACA-NH in the mixture at 24 h 2 Derive the absorbance of EtOH: Abs(DMACA-NH 2 EtOH) = Abs (mixture) at 474 nm - Abs (2DMACA-N 2 H 4 ) - mol.L of sample -1 NH in 2 The EtOH concentration was calculated using the calibration curve Abs(DMACA-NH 2 EtOH) = 117 [NH 2 EtOH] (Figure 8):

[0136]

number

[0137] c) If the interfering substance is morpholine, N 2 H 4 and the calculation of the morpholine concentration in a mixture containing morpholine is as follows: - N obtained in 5)a) 2 H 4 From the concentration, 2DMACA-N at 487 nm in 1 hour 2 H 4The absorbance of Abs(2DMACA-N) at 487 nm for 1 hour was calculated based on the calibration curve obtained in 2)a). 2 H 4 )=7810[N 2 H 4 ] (Figure 7). - Derive the absorbance of DMACA-morpholine in the mixture at 1 hour: Abs(DMACA-morpholine) at 487 nm = Abs(mixture) at 487 nm - Abs(2DMACA-N 2 H 4 ) - Using the calibration curve Abs(DMACA-morpholine) = 488 [morpholine] obtained in 3) b) (Figure 9), the mol.L -1 Derive the concentration of morpholine at:

[0138]

number

[0139] Example 2 [DMACA]=5×10 -3 M, [PSS] = 3.68 gL -1 (i.e. r = [H + ] / [DMACA]=4) in aqueous solution. 2 H 4 and N.H. 2 Protocol for assaying EtOH. This protocol uses r=[H + ] / [DMACA]=10, which is the same as described above in Example 1 for the reagent solution containing DMACA and PSS.

[0140] 542 nm (isosbestic point) and 474 nm (NH 2 At different wavelengths, r = [H + ] / [DMACA]=4 and [DMACA]=5×10 -3 M, [PSS] = 3.68 gL -1 Using a reagent solution containing N 2 H4 Establish the calibration curve: - At the isosbestic point (542 nm), Abs(542 nm) = Ax = 37744 [N 2 H 4 ]. - At 474 nm and 24 hours, Abs(474 nm, 24 hours) = A1x = 9599[N 2 H 4 ].

[0141] DMACA-NH at 474 nm for 24 h 2 A calibration curve for EtOH adducts is established. Abs(DMACA-NH) at 474 nm and 24 h 2 EtOH) = Bx = 429 [NH 2 EtOH]

[0142] Example 3 [DMACA]=5×10 -3 M, [PSS] = 9.2 gL -1 (i.e. r = [H + ] / [DMACA]=10) was used to prepare a reagent solution containing N 2 H 4 and N.H. 2 Protocol for Assaying EtOH (or Morpholine) For the measurement of gaseous analytes, gaseous N 2 H 4 and N.H. 2 EtOH and morpholine must be generated and their concentrations calibrated.

[0143] Gaseous N 2 H 4 and N.H. 2 The protocol for assaying EtOH (or morpholine) requires an additional step compared to the assay of these same analytes in aqueous solution, which corresponds to collecting the ambient air to be analyzed and sparging it into the liquid reagent.

[0144] The protocol is the same as that described in Example 1 for the determination of analytes in aqueous solution in steps 1), 2) and 3).

[0145] The sampling step 4) is as follows: the air to be analyzed is passed through a bubbler with a diameter of 3.16 cm and a height of 34 cm filled with 50 mL of the reagent solution prepared in step 1) at a rate of 1 L.min. -1 After 1 hour, collect the solution for spectrophotometric analysis.

[0146] The interfering substance is NH 2 In the case of EtOH, spectra of the mixture from 400 to 700 nm are collected at 5 minutes and after 24 hours.

[0147] If the interfering substance is morpholine, collect spectra of the mixture from 400 to 700 nm at 5 minutes and after 1 hour.

[0148] Calculation step 5) is the amount of N dissolved in the reagent. 2 H 4 and N.H. 2 It allows the determination of the concentration of EtOH (or morpholine). To find the concentration of these analytes in a gas mixture, 1 L.min -1 The total volume of gas pumped in one hour at a flow rate of

[0149] a)N 2 H 4 and N.H. 2 N in mixtures containing EtOH (or morpholine) 2 H 4 The concentration calculation is as follows: - r=[H + 2DMACA-N at isosbestic point 553 nm at ] / [DMACA]=10 2 H 4 Absorbance of the adduct (Abs). - The previously generated calibration curve at the isosbestic point according to the following equation: Abs(553 nm) = Ax = 29110[N 2 H 4 ] to calculate the mol.L of sample.-1 N in 2 H 4 Derive the cardinality:

[0150]

number

[0151] b)N 2 H 4 and N.H. 2 NH in mixtures containing EtOH 2 The calculation of EtOH concentration is as follows: - N obtained in 5)a) 2 H 4 From the concentration, 2DMACA-N at 474 nm and 24 hours 2 H 4 The absorbance of Abs(2DMACA-N) at 474 nm for 1 hour was calculated based on the calibration curve obtained in 2)a). 2 H 4 )=7080[N 2 H 4 ] (Figure 9). - DMACA-NH in the mixture at 24 h 2 The absorbance of EtOH is derived from: Abs(DMACA-NH 2 EtOH) = Abs (mixture) at 474 nm - Abs ((2DMACA-N 2 H 4 ) - mol.L of sample -1 NH in 2 The EtOH concentration was calculated using the calibration curve Abs(DMACA-NH 2 EtOH) = 117 [NH 2 EtOH]:

[0152]

number

[0153] c) If the interfering substance is morpholine, N 2 H4 and N.H. 2 The calculation of the morpholine concentration in the mixture containing EtOH is as follows: - N obtained in 5)a) 2 H 4 From the concentration, 2DMACA-N at 487 nm in 1 hour 2 H 4 The absorbance of Abs(2DMACA-N) at 487 nm for 1 hour was calculated based on the calibration curve obtained in 2)a). 2 H 4 )=7810[N 2 H 4 ] (Figure 9). - Derive the absorbance of DMACA-morpholine in the mixture at 1 hour: Abs(DMACA-morpholine) at 487 nm = Abs(mixture) at 487 nm - Abs((2DMACA-N 2 H 4 ) - 3) Using the calibration curve Abs(DMACA-morpholine) = 488 [morpholine] obtained in b) (Figure 11), the mol.L -1 Derive the concentration of morpholine at:

[0154]

number

[0155] d) N in gas mixtures in ppb 2 H 4 (or NH 2 The EtOH or morpholine) content is derived according to the following equation:

[0156]

number

[0157] Where: i=N 2 H 4 , N.H. 2 EtOH or morpholine

[0158]

number

[0159] (V = volume of reagent solution = 50 × 10 -3 L)

[0160]

number

[0161] (D = air flow rate = 1L.min -1 , t = sampling time = 1 hour, V m = Molar volume = 24.21 L.mol at 22°C -1 )

[0162] Example 4 in aqueous solutions containing different concentrations of the analyte, and 2 H 4 ]<[NH 3 ]<100[N 2 H 4 ] at strong base NH 3 N in the presence of 2 H 4 and N.H. 2 Application of the method according to the invention to the determination of EtOH. Reagent solution: [DMACA] = 5 x 10 -3 M, [PSS] = 9.2 gL -1 , i.e., r = [H + ] / [DMACA]=10 and isosbestic point at 553 nm. Here we present seven examples of application of the method. 3 ] / [N 2 H 4 ] and [NH 2 EtOH] / [N 2 H 4 ] with different ratios of known concentrations of N 2 H 4 , N.H. 2 EtOH and NH 3A mixture of 553 and 474 nm was prepared and the spectra of the mixture were collected for 24 hours. These spectra were analyzed by collecting absorbance values ​​at specific wavelengths, 553 and 474 nm, and N 2 H 4 and N.H. 2 The concentrations of EtOH were derived, and the calculated values ​​were then compared to the theoretical concentration values ​​(Table 1).

[0163] [Table 1]

[0164] This example demonstrates the very good reliability of the method according to the invention, especially with regard to the detection and quantification of hydrazine, since very small deviations (less than 6%) are observed between the calculated and theoretical values.

[0165] This example also shows that concentrations of interfering substances (NH 3 or NH 2 Despite the concentration of hydrazine in the ethanol (EtOH), the concentrations calculated via this method are very close to the theoretical concentrations, demonstrating the very good sensitivity of this method for the detection and quantification of hydrazine.

[0166] Example 5 in aqueous solutions containing different concentrations of the analyte and [NH 3 ]=150[N 2 H 4 ] at strong base NH 3 N in the presence of 2 H 4 and application of the method according to the invention to the determination of morpholine. Reagent solution: [DMACA] = 5 × 10 -3 M, [PSS] = 9.2 gL -1 , i.e., r = [H + ] / [DMACA]=10 and isosbestic point at 553 nm. Here we present four examples of the application of the analytical method. 3 ] / [N 2 H 4 ]=100 and [morpholine] / [N 2 H4 ] = 100 for known concentrations of N 2 H 4 , morpholine and NH 3 A mixture of 553 and 487 nm was prepared and the spectra of the mixture were collected for 1 hour. These spectra were analyzed by collecting absorbance values ​​at specific wavelengths, 553 and 487 nm, and N 2 H 4 The concentrations of morpholine and ammonium perchlorate were then derived. The calculated values ​​are then compared with the theoretical concentration values ​​(Table 2).

[0167] [Table 2]

[0168] As with Example 1, this example demonstrates the very good reliability of the method according to the invention, especially with regard to the detection and quantification of hydrazine, since very small deviations (less than 7%) are observed between the calculated and theoretical values.

[0169] This example also shows that the concentration of the interfering substance (NH 3 and morpholine), the concentrations calculated via this method are very close to the theoretical concentrations, demonstrating the very good sensitivity of this method for the detection and quantification of hydrazine.

[0170] Example 6 in aqueous solutions containing different concentrations of the analyte and [NH 3 ]=[NH 2 EtOH] = 96.55 [N 2 H 4 ] at strong base NH 3 N in the presence of 2 H 4 and N.H. 2 Application of the method according to the invention to the determination of EtOH. Reagent solution: [DMACA] = 5 x 10 -3 M, [PSS] = 3.68 gL -1 , i.e., r = [H + ] / [DMACA]=4 and isosbestic point at 542 nm. Here we present four examples of the application of the analytical method. 3 ] / [N 2 H 4 ]=96.55 and [NH 2 EtOH] / [N 2 H 4 ] = 96.55 for known concentrations of N 2 H 4 , N.H. 2 EtOH and NH 3 A mixture of N was prepared and the spectra of the mixture were collected for 24 hours. These spectra were analyzed by collecting absorbance values ​​at specific wavelengths, 542 nm and 474 nm. 2 H 4 and N.H. 2 The concentrations of EtOH were derived, and then the calculated values ​​were compared with the theoretical concentration values ​​(Table 3).

[0171] [Table 3]

[0172] As in the case of Examples 1 and 2, this example demonstrates the very good reliability of the method according to the invention, especially with regard to the detection and quantification of hydrazine, since very small deviations (less than 4%) are observed between the calculated and theoretical values.

[0173] This example also shows that the interfering substance concentration (NH 3 and N.H. 2 EtOH), the concentrations calculated using this method are very close to the theoretical concentrations, demonstrating the very good sensitivity of this method for the detection and quantification of hydrazine.

[0174] Example 7 N in the presence of interfering substances in industrial settings 2 H 4 Measurement of aqueous solution Liquid hydrazine measurements were performed on four samples collected at an industrial site. In addition to hydrazine, the samples also contained various concentrations of NH 2 EtOH+NH3 or morpholine + NH 3 The results of the measurements performed were systematically compared with automated amperometric measurements obtained on the sampled line and with measurements performed using pDMAB (p-dimethylaminobenzaldehyde) reagent. Figure 10 shows the set of results obtained.

[0175] This example shows that the method according to the present invention provides hydrazine concentration results that are very close to those obtained via the known method using pDMAB, specifically, a concentration difference of less than 2 μg / L is observed between the two methods.

[0176] Example 5 in ambient air containing different concentrations of the analyte and at 85[N 2 H 4 ]<[NH 3 ]<116[N 2 H 4 ] at strong base NH 3 Gaseous N in the presence of 2 H 4 and N.H. 2 Application of the method according to the invention to the determination of EtOH. Reagent solution: [DMACA] = 5 x 10 -3 M, [PSS] = 9.2 gL -1 , i.e., r = [H + ] / [DMACA]=10. Here we present five examples of application of the method. 3 ] / [N 2 H 4 ] and [NH 2 EtOH] / [N 2 H 4 ] with different ratios of known concentrations of N 2 H 4 , N.H. 2 EtOH and NH 3 The mixture was prepared by adding 1 L.min of the target air. -1 The mixture was pumped at a flow rate of 100 rpm and bubbled through 50 mL of the reagent for 1 hour. Spectra of the mixture were collected at 24 hours. These spectra were analyzed by collecting absorbance values ​​at specific wavelengths, 553 and 474 nm, and N2 H 4 and N.H. 2 The concentrations of EtOH were derived and then the calculated values ​​were compared to the theoretical concentration values ​​(Table 4).

[0177] [Table 4]

[0178] This example demonstrates the very good reliability of the method according to the invention applied to gaseous samples, in particular for the detection and quantification of hydrazine, since small deviations (less than 18%) are observed between the calculated and theoretical values.

[0179] This example also shows that the rate of interferences (NH 3 or NH 2 Regardless of the proportion of hydrazine in the gaseous sample (EtOH), the concentrations calculated using this method are very close to the theoretical concentrations, demonstrating the very good sensitivity of the method of the present invention applied to gaseous samples for the detection and quantification of hydrazine.

[0180] Example 6 in ambient air containing different concentrations of gaseous morpholine analyte and 57[N 2 H 4 ]<[NH 3 ]<164[N 2 H 4 ] at strong base NH 3 N in the presence of 2 H 4 Application of the method according to the invention to the determination of DMACA. Reagent solution: [DMACA] = 5 × 10 -3 M, [PSS] = 9.2 gL -1 , i.e., r = [H + ] / [DMACA]=10. Here we present seven examples of the application of the method. 3 ] / [N 2 H 4 ] and [morpholine] / [N 2 H 4 ] with different ratios of known concentrations of N2 H 4 , morpholine and NH 3 The mixture was prepared by adding 1 L.min of the target air. -1 The mixture was pumped at a flow rate of 100 rpm and bubbled through 50 mL of the reagent for 1 hour. Spectra of the mixture were collected at 1 hour. These spectra were analyzed by collecting absorbance values ​​at specific wavelengths, 553 and 487 nm, and N 2 H 4 The concentrations of morpholine and ammonium perchlorate were then derived. The calculated values ​​are then compared to the theoretical concentration values ​​(Table 5).

[0181] [Table 5]

[0182] As in Example 5, this example demonstrates the very good reliability of the method according to the invention applied to gaseous samples, especially with regard to the detection and quantification of hydrazine, since small deviations (less than 16%) are observed between the calculated and theoretical values.

[0183] This example also shows that the rate of interferences (NH 3 or morpholine), the concentrations calculated using this method are very close to the theoretical concentrations, demonstrating the very good sensitivity of the method according to the invention applied to gaseous samples for the detection and quantification of hydrazine.

[0184] Example 9 Gaseous N at two concentration levels 2 H 4 Measurement Examples Air samples were taken from the gas headspace of two closed tanks containing concentrated hydrazine solutions. The concentration of hydrazine in the liquid phase is not precisely known but is estimated to be 1% by mass.

[0185] Since the concentration of hydrazine in a gaseous sample is unknown, the aim of this experiment is to investigate the reproducibility of the method according to the invention for the determination of hydrazine in this sample.

[0186] The duration of sampling and sparging in the reagent solution (DMACA / PSS at r=10) is 1 hour.

[0187] [Table 6]

[0188] With the low standard deviations reported in the table above, this experiment demonstrates good reproducibility of the method for hydrazine quantification in gaseous samples.

[0189] In order to evaluate the reproducibility of the method for samples with lower concentrations, 20 samples were taken at a distance of 7 meters from the tank 1 mentioned above, covered with a non-hermetic lid. These samples were taken under identical experimental conditions. A hydrazine concentration of 1.80 ppb was measured. Figure 11 shows the distribution of the results obtained for all samples generated.

[0190] This experiment demonstrates extremely good reproducibility of the method according to the invention applied to gaseous samples with low hydrazine concentrations, since all results except for one measurement show quite minimal measurement variability of less than 0.5 ppb.

[0191] References list (References) TIFF2025079338000024.tif175165TIFF2025079338000025.tif242164TIFF2025079338000026.tif174165

Claims

1. 1. A method for detecting at least one amine-type compound in an analyte sample using a reagent composition comprising a mixture of 4-(dimethylamino)cinnamaldehyde and polystyrene sulfonic acid, comprising: the amine type compound is selected from hydrazine, ethanolamine, ammonia and morpholine; The method further comprising: a) mixing the sample to be analyzed with the reagent composition to obtain a mixture of the sample to be analyzed and the reagent composition; b) detecting the amine-type compound in the mixture of the analyte sample and the reagent composition; A method comprising:

2. 2. The method of claim 1, wherein step b) also comprises quantifying the amine-type compound in the mixture of the analyte sample and the reagent composition.

3. 3. The method according to claim 1, wherein the sample to be analyzed is a liquid or gaseous sample or an aerosol.

4. 4. The method according to claim 1, wherein the detection or detection and quantification step b) is carried out by measuring the absorbance as a function of time of the mixture of the sample to be analyzed and the reagent composition.

5. 5. The method according to claim 1, wherein the ratio r between the concentration of 4-(dimethylamino)cinnamaldehyde and the concentration of polystyrene sulfonic acid is from 1 to 20, preferably from 2 to 15, and even more preferably 10.

6. A reagent composition comprising a mixture of 4-(dimethylamino)cinnamaldehyde and polystyrene sulfonic acid.

7. 7. The composition according to claim 6, wherein the ratio r of the concentration of 4-(dimethylamino)cinnamaldehyde to the concentration of polystyrene sulfonic acid is from 1 to 20, preferably from 2 to 15, even more preferably 10.

8. 8. Use of the reagent composition according to claim 6 or 7 for the detection of at least one amine type compound, wherein said amine type compound is selected from hydrazine, ethanolamine and morpholine.

9. 8. Use of the reagent composition according to claim 6 or 7 for the determination of at least one amine type compound, wherein said amine type compound is selected from hydrazine, ethanolamine and morpholine.

10. A kit for preparing the reagent composition according to claim 6 or 7, comprising: - a first container containing 4-(dimethylamino)cinnamaldehyde; - a second container containing an aqueous solution of polystyrene sulfonic acid; A kit comprising:

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