A detection probe and a method for detecting water in methanol solvent

Abstract

The present invention relates to the technical field of solvent detection and molecular probes, and in particular to a detection probe and a method for detecting water in a methanol solvent. The present invention uses a metal palladium complex as a detection probe for detecting the water content in methanol, and the range of the water content can be judged by observing the change in color with the naked eye, and the specific value of the water content can be accurately detected by the data of ultraviolet and fluorescence spectra, thereby simplifying and reducing the detection cost of solvent molecules. In addition, a metal palladium complex is used as a detection probe, and the detection range of water in a methanol solvent under a fluorescent channel is 0.11-100%, and the detection range of water in a methanol solvent under an ultraviolet-visible light detection channel is 12.27-100%, and the detection range of water in a methanol solvent is large, and the detection of high water content in methanol can be achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of solvent detection and molecular probes, and more particularly to a detection probe and a method for detecting water in a methanol solvent. Background Art

[0002] Methanol, a vital industrial raw material, has a purity that directly impacts the quality of downstream products. The water content of methanol can affect its efficiency in reactions and the purity of the resulting products. Furthermore, in chemical synthesis or pharmaceutical production, water in methanol can affect reaction efficiency and product purity. During methanol production and storage, the presence of water can lead to incomplete reactions or the occurrence of side reactions. Methanol and water mixtures can exhibit different physical and chemical properties, impacting their safe storage and transportation. Identifying the presence of water in methanol and testing its water content can help assess and manage these risks and ensure operational safety.

[0003] Currently, there are multiple methods for measuring the water content in methanol, including Karl Fischer titration, gas chromatography (GC), infrared spectroscopy (IR), and conductivity. Each of these methods has its own advantages for detecting water content in methanol. Karl Fischer titration accurately measures water content and is suitable for detecting even trace amounts of water. However, this method requires specialized Karl Fischer reagents and instrumentation, resulting in high equipment and reagent costs. Similarly, gas chromatography also presents the issue of expensive instrumentation. Infrared spectroscopy can rapidly measure water content, but its detection range is limited, and other substances may interfere with the water detection, resulting in low accuracy and stability. While conductivity is simple to operate, the detection process is susceptible to interference from other ions, reducing accuracy. Therefore, these methods present varying degrees of challenges in detecting water content in methanol.

[0004] With the development of molecular probe technology, many chemical probes have been designed and synthesized. Using simple optical instruments to detect optical properties, changes in optical properties are an efficient and rapid method for reflecting changes in the water content of methanol solvents. Currently, many probes for detecting water in methanol solvents have been reported, but most focus on fluorescence spectroscopy and the range of water content in methanol solvents varies. Summary of the Invention

[0005] Aiming at the technical deficiency that the current detection probe for detecting water in methanol solvent can only realize single channel detection, the present invention adopts As a detection probe, It is possible to detect water in methanol solvent based on changes in fluorescence properties and ultraviolet-visible light properties, thereby realizing multi-channel detection of water in methanol solvent.

[0006] One of the objectives of the present invention is to provide a detection probe.

[0007] The structural formula of the detection probe is: .

[0008] The detection probe is a metal palladium complex, and its hydrogen nuclear magnetic resonance spectrum is characterized by 1 H NMR (500 MHz, [D6] DMSO): δ = 8.44 [s, 1H, C(H)-N], 8.35 (d, 1H, J = 5.5 Hz, Py), 8.14 (t,1H, J = 7.5 Hz, Py), 7.76 (d, 1H, J = 8 Hz, Py), 7.6(t, 1H, J = 7 Hz, Py), 7.38(d, 1H, J = 7 Hz, phenol), 7.04 (t, 1H, J = 10 Hz, phenol), 6.47 (m, 2H,phenol) ppm. 13 C NMR (125 MHz, [D6] DMSO) δ: 176.42, 161.79, 152.15, 151.78,142.10, 135.78, 134.76, 128.09, 120.41, 119.36, 116.20.

[0009] The preparation method of the detection probe can adopt the preparation method in the prior art. The preparation method adopted by the present invention comprises: the first step: pyridine-2-carboxaldehyde and o-aminophenol react to obtain a Schiff base ligand ; The second step reaction: the Schiff base ligand reacts with sodium tetrachloropalladate (Na2PdCl4) to obtain the detection probe .

[0010] The synthetic route of the detection probe is as follows:

[0011] .

[0012] The preparation method may comprise the following steps:

[0013] 1) dissolving pyridine-2-carboxaldehyde and o-aminophenol in a solvent to obtain a mixed solution;

[0014] 2) The mixed solution obtained in step 1) was heated to 60-65°C, stirred at constant temperature for 1-1.5 hours, filtered under reduced pressure, and recrystallized with dichloromethane to obtain a Schiff base ligand. ;

[0015] 3) reacting the Schiff base ligand obtained in step 2) with sodium tetrachloropalladate in a solvent system to obtain a red precipitate; the reaction temperature is 60-70° C., and the reaction time is 34-36 hours;

[0016] 4) Washing and recrystallizing the red precipitate to obtain a red solid; the obtained red solid is the detection probe.

[0017] In step 1), the molar ratio of pyridine-2-carboxaldehyde to o-aminophenol can be limited to (1:1.2) to (1:1.5), which helps to improve the reaction yield; the solvent is an organic solvent, specifically methanol.

[0018] In step 3), the molar ratio of the Schiff base ligand to sodium tetrachloropalladate can be (1:1) to (1.2:1); and the solvent system can be a mixture of ethanol and water in a volume ratio of 1:1.

[0019] In step 4), the washing may be performed with cold anhydrous ethanol, the temperature of which is about -35°C; the recrystallization may be performed with dichloromethane / n-hexane and water, the volume ratio of which may be 5:1.

[0020] In the structure of the detection probe, palladium (Pd) metal bonds with imine nitrogen, pyridinic nitrogen, phenolic hydroxyl oxygen, and a chlorine atom to form a tetracoordinate structure, resulting in a nearly planar molecular configuration. The oxygen atoms in the detection probe readily form hydrogen bonds with protic solvents. Methanol and water are both protic solvents, and the detection probe can form hydrogen bonds with both, providing the basic conditions for detecting water in methanol.

[0021] A second object of the present invention is to provide a method for detecting water in a methanol solvent.

[0022] The detection method comprises using the detection probe described in one of the objectives of the invention to detect water in a methanol solvent.

[0023] The detection probe includes a detection probe solution. The detection probe solution is an anhydrous methanol solution of the detection probe. The concentration of the detection probe solution can be 1.0×10 -4 mol / L to 0.8×10 -4 mol / L, preferably 0.8×10 - 4mol / L. The color of the detection probe solution is rose red. The volume ratio of the methanol solvent to be tested to the detection probe solution can be any ratio, preferably 9:1.

[0024] Aqueous methanol solvents with a water content in the range of 10-100% (excluding 100%) can cause a visually discernible color change in the detection probe solution, while methanol solvents with a water content below 10% cannot cause a visually discernible color change in the detection probe solution. Therefore, whether the methanol solvent to be tested causes a visually discernible color change in the detection probe solution can be used to determine whether the test methanol solvent contains 10-100% water, thereby achieving qualitative detection of whether the test methanol solvent contains 10-100% water.

[0025] Specifically, when the methanol solvent changes the color of the detection probe solution from rose red to light red, it indicates that the methanol solvent contains 10-100% water. When the methanol solvent does not change the color of the detection probe solution (remains rose red), it indicates that the water content of the methanol solvent is less than 10%. The water content of the methanol solvent being less than 10% includes the water content of the methanol solvent being zero, that is, the methanol solvent being free of water.

[0026] Within the water content range of 10-100%, when methanol solvents with varying water contents are added to the same concentration of the detection probe solution (the color of the detection probe solutions of the same concentration is identical), the color of the detection probe solution changes to varying degrees. Specifically, as the water content of the added methanol solvent increases, the color of the detection probe solution gradually changes from light red to light pink. Therefore, the water content range of the methanol solvent being tested can be determined based on the color of the detection probe solution after addition, enabling quantitative detection of the water content of the methanol solvent being tested.

[0027] Specifically, the method includes: mixing the methanol solvent to be tested with the detection probe solution to obtain a test liquid; comparing the color of the test liquid with a standard color card to obtain the water content range of the methanol solvent to be tested; the standard color card includes multiple colors and corresponding methanol solvent water contents.

[0028] The standard color card can be prepared by the following method: adding multiple methanol solvents with different and known water contents into the detection probe solution to obtain multiple standard solutions with different colors. The colors of the multiple standard solutions and the corresponding water contents of the methanol solvents constitute the standard color card.

[0029] The standard color card includes rose red, light red, light red, and multiple colors between rose red and light red. Each color corresponds to a water content of the methanol solvent, and the water content is a point value. Different colors correspond to different water contents of the methanol solvent. The water content of the methanol solvent corresponding to rose red is zero. The color of the detection probe solution used to prepare the test solution is the same as the color corresponding to the methanol solvent water content of zero in the standard color card.

[0030] Aqueous methanol solvents with a water content of 12.27-100% (excluding 100%) can cause a blue shift in the UV-visible absorption spectrum of the detection probe solution from 532 nm, accompanied by a decrease in the absorption peak. Therefore, whether the methanol solvent to be tested causes a blue shift in the UV-visible absorption spectrum of the detection probe from 532 nm, accompanied by a decrease in the absorption peak, can be used to determine whether the methanol solvent to be tested contains 12.27-100% water, thereby achieving qualitative detection of whether the methanol solvent to be tested contains 12.27-100% water.

[0031] Specifically, when the tested methanol solvent causes the ultraviolet-visible absorption spectrum of the detection probe solution to blue shift from 532 nm and is accompanied by a decrease in the absorption peak, it indicates that the tested methanol solvent contains 12.27-100% water; when the tested methanol solvent does not cause the ultraviolet-visible absorption spectrum of the detection probe solution to blue shift from 532 nm or is not accompanied by a decrease in the absorption peak, it indicates that the water content in the tested methanol solvent is less than 12.27%. The water content in the tested methanol solvent being less than 12.27% includes the water content in the tested methanol solvent being zero, that is, including the fact that the tested methanol solvent contains no water.

[0032] Within the water content range of 12.27-100%, when methanol solvents with different water contents are added to a detection probe solution of the same concentration, the extent to which their UV-visible absorption spectra decrease from the absorption peak at 500-532 nm varies. Therefore, after determining that the methanol solvent to be tested contains 12.27-100% water, the water content of the added methanol solvent to be tested can be determined by measuring the absorbance at the absorption peak of the UV-visible absorption spectrum of the probe solution after adding the methanol solvent to be tested, thereby achieving quantitative determination of the water content of the methanol solvent to be tested.

[0033] Specifically, the method includes: mixing the methanol solvent to be tested with the detection probe solution to obtain a detection liquid, measuring the ultraviolet spectral properties of the detection liquid to obtain the absorbance of the detection liquid at the absorption peak of 500-532nm; comparing the obtained absorbance with the absorbance-water content calibration curve to obtain the water content of the methanol solvent to be tested; or, calculating the obtained absorbance using the absorbance-water content fitting function to obtain the water content of the methanol solvent to be tested.

[0034] The absorbance-water content standard curve can be drawn by the following method: adding multiple methanol solvents with different and known water contents to the detection probe solution to obtain multiple standard solutions; measuring the ultraviolet spectral properties of each standard solution to obtain the absorbance of each standard solution at an absorption peak between 500 and 532 nm; and then drawing the absorbance-water content standard curve based on the water content of each standard solution and the absorbance of the absorption peak between 500 and 532 nm. The water content of the standard solution refers to the water content of the methanol solvent used to prepare the standard solution.

[0035] The absorbance-water content fitting function can be obtained by the following method: adding multiple methanol solvents with different and known water contents to the detection probe solution to obtain multiple standard solutions; measuring the ultraviolet spectral properties of each standard solution to obtain the absorbance of each standard solution at an absorption peak at 500-532nm; and then performing a linear fit between the water content of each standard solution and the absorbance of the absorption peak at 500-532nm to obtain the absorbance-water content fitting function. The water content of the standard solution refers to the water content of the methanol solvent used to prepare the standard solution.

[0036] According to the embodiment disclosed in the present invention, the absorbance-water content fitting function is y=-9.99394*10 -4 x+0.20587, where x is the water content of the added methanol solvent and y is the absorbance.

[0037] The concentration of the detection probe solution used to obtain the test liquid is the same as the concentration of the detection probe solution used when drawing the absorbance-water content standard curve or the concentration of the detection probe solution used when obtaining the absorbance-water content fitting function. Specifically, when the water content of the methanol solvent to be tested is obtained by "comparing the obtained absorbance with the absorbance-water content standard curve to obtain the water content of the methanol solvent to be tested", the concentration of the detection probe solution used to obtain the test liquid is the same as the concentration of the detection probe solution used when drawing the absorbance-water content standard curve; when the water content of the methanol solvent to be tested is obtained by "calculating the obtained absorbance using the absorbance-water content fitting function to obtain the water content of the methanol solvent to be tested", the concentration of the detection probe solution used to obtain the test liquid is the same as the concentration of the detection probe solution used when obtaining the absorbance-water content fitting function.

[0038] The structure of the detection probe molecule is a planar structure. Such a structure increases the rigidity of the molecular system and improves the conjugation performance between the benzene rings, which is conducive to fluorescence emission. In the methanol solvent, the oxygen atoms in the methanol molecules and the hydrogen atoms in the detection probe, as well as the hydrogen atoms in the methanol molecules and the oxygen atoms in the detection probe, form hydrogen bonds. This hydrogen bonding makes the planar structure of the detection probe more rigid. At the same time, under the action of hydrogen bonds, a certain structural stacking pattern is generated between the plane molecules of the detection probe. This stacking avoids the face-to-face stacking of the molecular planes, thereby forming a misplaced stacking connected end to end. At the same time, a spatial network structure is formed between adjacent groups of molecules through chlorine atoms (one Cl is connected to two palladiums by a coordination bond). This spatial stereo configuration caused by intermolecular hydrogen bonds causes the detection probe to produce fluorescence enhancement in an aggregated state.

[0039] When water molecules enter the system, they will cause the detection probe molecules in the system to aggregate. After the detection probe molecules aggregate, they will further self-assemble through the intramolecular hydrogen bonding and π-π interaction to form a supramolecular structure. Such a structure increases the distance between molecules and weakens the interaction between molecules, which is conducive to enhanced fluorescence emission. That is, after adding water in different proportions, the fluorescence intensity of the detection probe will further increase. This increase is not due to the protonity of water, but because water as a poor solvent causes the system to emit aggregation, which is aggregation-induced fluorescence enhancement. Therefore, whether the methanol solvent to be tested contains water can be detected by changing the fluorescence emission intensity of the detection probe.

[0040] Aqueous methanol solvents with a water content of 0.11-100% (excluding 100%) can enhance the emission peak of the fluorescence emission spectrum of the detection probe solution at 370 nm. Therefore, whether the methanol solvent to be tested enhances the emission peak of the fluorescence emission spectrum of the detection probe at 370 nm can be used to determine whether the methanol solvent to be tested contains 0.11-10% water, thereby achieving qualitative detection of whether the methanol solvent to be tested contains 0.11-10% water.

[0041] Specifically, when the methanol solvent to be tested enhances the emission peak at 370 nm of the fluorescence emission spectrum of the anhydrous methanol solvent of the detection probe, the methanol solvent to be tested contains 0.11-100% water; when the methanol solvent to be tested does not enhance the emission peak at 370 nm of the fluorescence emission spectrum of the anhydrous methanol solvent of the detection probe, the water content of the methanol solvent to be tested is less than 0.11%. The water content of the methanol solvent to be tested being less than 0.11% includes the water content of the methanol solvent to be tested being zero, that is, including the methanol solvent to be tested containing no water.

[0042] Within the water content range of 0.11-99%, as the water content of the methanol solvent increases, the system aggregates, causing fluorescence enhancement, and the emission peak of the fluorescence emission spectrum at 370nm is further enhanced. That is, after adding methanol solvents with different water contents to the detection probe solution of the same concentration, the degree of enhancement of the emission peak of the fluorescence emission spectrum at 370nm is different. Therefore, after determining that the methanol solvent to be tested contains 0.11-100% water, the fluorescence emission intensity of the fluorescence emission spectrum of the probe solution at 370nm after adding the methanol solvent to be tested can be used to determine the water content of the added methanol solvent to be tested, thereby achieving quantitative determination of the water content of the methanol solvent to be tested.

[0043] Specifically, the method includes: adding the methanol solvent to be tested to the detection probe solution to obtain a detection liquid, measuring the fluorescence spectral properties of the detection liquid, and obtaining the fluorescence emission intensity of the detection liquid at 370 nm; comparing the obtained fluorescence emission intensity with the fluorescence emission intensity-water content standard curve to obtain the water content of the methanol solvent to be tested; or, calculating the obtained fluorescence emission intensity using a fluorescence emission intensity-water content fitting function to obtain the water content of the methanol solvent to be tested.

[0044] The fluorescence emission intensity-water content standard curve can be drawn by the following method: adding multiple methanol solvents with different and known water contents to the detection probe solution to obtain multiple standard solutions; measuring the fluorescence spectral properties of each standard solution to obtain the fluorescence emission intensity of each standard solution at 370 nm; and then drawing a fluorescence emission intensity-water content standard curve based on the water content of each standard solution and its fluorescence emission intensity at 370 nm. The water content of the standard solution refers to the water content of the methanol solvent used to prepare the standard solution.

[0045] The fluorescence emission intensity-water content fitting function can be obtained by the following method: adding multiple methanol solvents with different and known water contents to the detection probe solution to obtain multiple standard solutions; measuring the fluorescence spectral properties of each standard solution to obtain the fluorescence emission intensity of each standard solution at 370nm; and then performing a linear fit between the water content of each standard solution and its fluorescence emission intensity at 370nm to obtain a fluorescence emission intensity-water content fitting function. The water content of the standard solution refers to the water content of the methanol solvent used to prepare the standard solution.

[0046] According to an embodiment disclosed in the present invention, the fluorescence emission intensity-water content fitting function is y=2.00901x+94.34215, wherein x is the water content of the added methanol solvent, and y is the fluorescence emission intensity at 370 nm.

[0047] The concentration of the detection probe solution used to obtain the test liquid is the same as the concentration of the detection probe solution used when drawing the fluorescence emission intensity-water content standard curve or the concentration of the detection probe solution used when obtaining the fluorescence emission intensity-water content fitting function. Specifically, when the water content of the methanol solvent to be tested is obtained by "comparing the obtained fluorescence emission intensity with the fluorescence emission intensity-water content standard curve to obtain the water content of the methanol solvent to be tested", the concentration of the detection probe solution used to obtain the test liquid is the same as the concentration of the detection probe solution used when drawing the fluorescence emission intensity-water content standard curve; when the water content of the methanol solvent to be tested is obtained by "calculating the obtained fluorescence emission intensity using the fluorescence emission intensity-water content fitting function to obtain the water content of the methanol solvent to be tested", the concentration of the detection probe solution used to obtain the test liquid is the same as the concentration of the detection probe solution used when obtaining the fluorescence emission intensity-water content fitting function.

[0048] The detection probe of the present invention can realize the detection of three channels of water in methanol solvent.

[0049] The first channel detects the presence and amount of water in the methanol solvent by observing the visible color change before and after the probe solution is added to the methanol solvent. The fluorescent probe has a detection limit of 10% for water content, with a detection range of 10-100% (excluding 100%).

[0050] The second detection channel identifies the presence and amount of water in the methanol solvent by observing changes in the UV-visible absorption spectrum of the probe solution before and after addition, as well as the absorbance of the absorption peak. The fluorescent probe has a detection limit of 12.27% for water content in the methanol solvent, with a detection range of 12.27% to 100% (excluding 100%).

[0051] The third detection channel detects the presence and amount of water in the methanol solvent by observing changes in the fluorescence emission spectrum and the intensity of the emission peak before and after the probe solution is added to the methanol solvent. The fluorescent probe has a detection limit of 0.11% for water content in the methanol solvent, with a detection range of 0.11-100% (excluding 100%).

[0052] Compared with the prior art, the present invention has the following beneficial effects:

[0053] The method of the present invention adopts the structural formula The metal palladium complex is used as a detection probe to detect methanol solvents with different water contents, providing a new detection method for the detection of water in methanol solvents.

[0054] The metal palladium complex is used as a detection probe for detecting the water content in methanol. The range of the water content can be judged by observing the color change with the naked eye, and the specific value of the water content can be accurately detected through ultraviolet and fluorescence spectrum data, thereby simplifying and reducing the detection cost of solvent molecules.

[0055] The metal palladium complex is used as a detection probe to detect methanol solvents with different water contents through a colorimetric channel, an ultraviolet-visible light channel, and a fluorescence channel, and is a detection method that can simultaneously detect and calculate the water content.

[0056] In addition, the use of As a detection probe, the detection range of water in methanol solvent is 0.11-100% under the fluorescence channel, and the detection range of water in methanol solvent is 12.27-100% under the UV-visible light detection channel. The detection range of water in methanol solvent is large, and it can realize the detection of high water content in methanol.

[0057] The metal palladium complex has the advantages of simple molecular structure, simple synthesis, high yield, low cost, etc. as a detection probe.

[0058] The method for identifying and detecting the water content in a methanol solvent by using the metal palladium complex as a detection probe is simple, easy to operate, has a low detection limit, a large detection range, and high sensitivity.

[0059] In the present invention, unless otherwise specified, the “10-100%” does not include 100%, the “12.27-100%” does not include 100%, and the “0.11-100%” does not include 100%.

[0060] In the present invention, unless otherwise specified, the water content is by volume. BRIEF DESCRIPTION OF THE DRAWINGS

[0061] Figure 1 The volume content of water is 0%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90% respectively, and the concentration of methanol is 0.8×10 -3 mol / L color diagram of the metal palladium complex; Figure 1 In the figure, the corresponding water contents from left to right are 0%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, and 90%;

[0062] Figure 2A The concentration is 0.8×10 -4 UV-visible absorption spectrum of an anhydrous methanol solution of a mol / L metal palladium complex with a water content of 0-90% by volume in methanol; wherein the abscissa is the excitation wavelength and the ordinate is the absorbance;

[0063] Figure 2B is based on Figure 2A The obtained absorbance-water content standard curve is a graph in which the horizontal axis represents the water content of the methanol solvent and the vertical axis represents the absorbance of the UV-visible absorption spectrum at 532 nm;

[0064] Figure 3A The concentration is 0.8×10 -4 mol / L of anhydrous methanol solution of a metal palladium complex selectively to methanol with a water content of 0-90% by volume; wherein the abscissa is the emission wavelength and the ordinate is the fluorescence emission intensity;

[0065] Figure 3B is based on Figure 3A The obtained emission intensity-water content standard curve graph, wherein the abscissa is the water content of the methanol solvent, and the ordinate is the fluorescence emission intensity of the fluorescence emission spectrum at 370 nm. DETAILED DESCRIPTION

[0066] The present invention will be described in detail below with reference to specific drawings and embodiments. It is necessary to point out that the following embodiments are only used to further illustrate the present invention and cannot be understood as limiting the scope of protection of the present invention. Some non-essential improvements and adjustments made by those skilled in the art to the present invention based on the contents of the present invention still fall within the scope of protection of the present invention.

[0067] In the following examples, all reagents used are commercially available reagents.

[0068] Example 1

[0069] Synthesis of palladium complexes

[0070] Accurately weigh 110 mg of o-aminophenol and dissolve it in 10 mL of methanol. Add 1 mL of pyridine-2-carboxaldehyde to the solution, stirring, and heat to 60°C, stirring constantly for 1-1.5 hours. After the reaction is complete, filter the oil under reduced pressure. Add 5 mL of dichloromethane and 1 mL of n-hexane, and place in a -20°C refrigerator overnight. The next day, a light yellow product A is obtained. The light yellow product A is a Schiff base, and its purity is sufficient for direct use in the next reaction.

[0071] Weigh 40 mg of Schiff's base and dissolve it in 5 mL of ethanol. Weigh 58 mg of sodium tetrachloropalladate and dissolve it in the aqueous solution. Add the aqueous solution containing sodium tetrachloropalladate dropwise to the Schiff's base ethanol solution. Heat the reaction solution to 78°C and reflux for 36 hours to obtain a red precipitate. Cool the reaction solution, filter it, and wash the reaction product several times with cold ethanol. The resulting dark red solid is the metal palladium complex.

[0072] The red solid product was confirmed to be a metal palladium complex by nuclear magnetic resonance and single crystal testing, and its structural formula is , whose molecular formula is C 14 H9ClN2OPd.

[0073] Yield: 81%, mp 246℃℃. 1 H NMR (500 MHz, [D6] DMSO): δ = 8.44 [s, 1H,C(H)-N], 8.35 (d, 1H, J = 5.5 Hz, Py), 8.14 (t, 1H, J = 7.5 Hz, Py), 7.76 (d,1H, J = 8 Hz, Py), 7.6 (t, 1H, J = 7 Hz, Py), 7.38 (d, 1H, J = 7 Hz, phenol), 7.04 (t, 1H, J = 10 Hz, phenol), 6.47 (m, 2H, phenol) ppm. 13 C NMR (125 MHz, [D6] DMSO) δ: 176.42, 161.79, 152.15, 151.78, 142.10, 135.78, 134.76, 128.09,120.41, 119.36, 116.20.

[0074] Example 2

[0075] Visual recognition of alcohol solvents by a metal palladium complex (i.e., probe L).

[0076] Accurately weigh 3.00 mg of the metal palladium complex prepared in Example 1, dissolve it in anhydrous methanol and prepare a concentration of 0.8×10 -3 mol / L probe L solution. The color of the probe L solution is rose red.

[0077] Take 10 portions of 0.3 mL to a concentration of 0.8 × 10 -3 mol / L probe L solution was placed in 10 sample bottles, and then 2.7 mL of methanol solvent with different water contents was added to each sample bottle, shaken well, and allowed to stand for 20-30 minutes; the water contents of the methanol solvents were 0%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, and 90% in sequence. The color changes of the probe L solutions in the 10 sample bottles are as follows: Figure 1 As shown. Figure 1As shown, when methanol with a water content of 0% is added, the color of the Probe L solution turns rose-red. When methanol with a water content of 10-90% is added, the color of the Probe L solution changes to light red. The light red color of the Probe L solution gradually intensifies as the water content of the added methanol increases. This phenomenon allows the naked eye to instantly identify whether the methanol solvent contains 10-100% (not 100%) water.

[0078] Example 3

[0079] UV-visible spectral recognition performance of the metal palladium complex (i.e., probe L) for alcohol solvents.

[0080] Accurately weigh 3.00 mg of the metal palladium complex prepared in Example 1, dissolve it in anhydrous methanol and prepare a concentration of 0.8×10 -4 mol / L probe L solution.

[0081] Take 10 portions of 0.3 mL to a concentration of 0.8 × 10 -4 mol / L probe L solution was placed in 10 sample bottles, and then 2.7 mL of methanol solvent with different water contents was added to each sample bottle; the water content of the methanol solvent was 0%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, and 90% in sequence. The solution was shaken and allowed to stand for 20-30 minutes, and the UV-visible absorption spectrum of the probe L solution in each sample bottle was measured. Figure 2A shown.

[0082] according to Figure 2A The UV-visible absorption spectrum of a solution of Probe L containing 0% methanol (i.e., pure anhydrous methanol) showed two absorption peaks at 308 nm and 532 nm. When 10-90% methanol was added, the 532 nm absorption peak of the Probe L solution shifted to the blue and decreased. As the water content of the added methanol increased, the degree of blue shift in the 532 nm absorption peak of the Probe L solution increased, and the absorbance gradually decreased. The peak at 308 nm is not relevant to this application.

[0083] according to Figure 2A Obtain the absorbance of the probe L solution at 532 nm after adding methanol solvents with different water contents; draw a standard curve of absorbance-water content with the absorbance of the probe L solution at 532 nm after adding methanol solvents with different water contents as the ordinate and the water content of the added methanol solvent as the abscissa, as shown in FIG. Figure 2B The absorbance of the probe L solution at 532 nm after adding methanol solvent with different water contents was linearly fitted with the change in water content of the added methanol solvent, and the linear equation y=-9.99394*10 -4x+0.20587, where x is the water content of the added methanol solvent and y is the absorbance. Correlation R of the linear equation 2 =0.99040, indicating that there is a good linear relationship between the water content of the added methanol solvent and the change in absorbance of the probe L solution at 532 nm after adding methanol solvents with different water contents.

[0084] The detection limit of probe L for the water content of methanol solvent was calculated to be 12.27% by using the LOD=3N / S calculation method (a method known in the art).

[0085] Example 4

[0086] Fluorescence spectroscopy recognition performance of the metal palladium complex (i.e., probe L) for alcohol solvents (excitation wavelength of 300 nm, slit of 5 nm).

[0087] Accurately weigh 3.00 mg of the metal palladium complex prepared in Example 1, dissolve it in anhydrous methanol and prepare a concentration of 0.8×10 -4 mol / L probe L solution.

[0088] Take 10 portions of 0.3 mL to a concentration of 0.8 × 10 -4 mol / L probe L solution was placed in 10 sample bottles, and then 2.7 mL of methanol solvent with different water contents was added to each sample bottle; the water content of the methanol solvent was 0%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, and 90% in sequence. The solution was shaken and allowed to stand for 20-30 minutes, and the fluorescence emission spectrum of the probe L solution was measured. Figure 3A shown.

[0089] according to Figure 3A It was found that when a methanol solvent with a water content of 0% (i.e., pure anhydrous methanol solvent) was added, the fluorescence emission spectrum of the probe L solution showed emission at 370nm; when methanol solvents with different water contents (10-90%) were added, the emission peak of the probe L solution at 370nm was enhanced, accompanied by a slight red shift; as the water content of the added methanol solvent increased, the degree of enhancement of the emission peak of the probe L solution at 370nm increased.

[0090] according to Figure 3A The fluorescence emission intensity of the probe L solution at 370 nm after adding methanol solvents with different water contents was obtained; the fluorescence emission intensity of the probe L solution at 370 nm after adding methanol solvents with different water contents was used as the ordinate, and the water content of the added methanol solvent was used as the abscissa to draw a standard curve of fluorescence emission intensity-water content, as shown in FIG. Figure 3BAs shown. The fluorescence emission intensity of the probe L solution at 370nm after adding methanol solvent with different water contents was linearly fitted with the change in the water content of the added methanol solvent, and the linear equation y=2.00901x+94.34215 was obtained, where x is the water content of the added methanol solvent and y is the fluorescence emission intensity at 370nm. R is the correlation of the linear equation of the fluorescence emission intensity. 2 =0.99647, indicating that there is a good linear relationship between the water content of the added methanol solvent and the change in the fluorescence emission intensity of the probe L solution at 370 nm after adding methanol solvents with different water contents.

[0091] The detection limit of probe L for water content in methanol was calculated to be 0.11% by using the LOD=3N / S calculation method.

[0092] Example 5

[0093] Detection of a metal palladium complex (i.e., probe L) in a methanol solvent with unknown water content.

[0094] Accurately weigh 3.00 mg of the metal palladium complex prepared in Example 1, dissolve it, and prepare it to a concentration of 0.8×10 - 3 mol / L anhydrous methanol solution of metal palladium complex, and then diluted to a concentration of 0.8×10 -4 mol / L, and obtain probe L solution.

[0095] Take 0.3mL of the solution with a concentration of 0.8×10 -3 mol / L probe L solution in a sample bottle, add 2.7mL of the solution to be tested, shake well, let it stand for 20-30 minutes after equilibrium, and observe the color of the solution. Figure 1 Compare with the standard color card shown to roughly determine the water content range of the solution to be tested;

[0096] UV channel detection: take 0.3mL with a concentration of 0.8×10 -4 mol / L probe L solution in a sample bottle, add 2.7mL of the test solution, shake well, and let it stand for 20-30 minutes after equilibrium. Measure the ultraviolet spectrum performance of the probe L solution to obtain the ultraviolet absorbance of the test solution at 532nm; compare the obtained absorbance value with the absorbance-water content standard curve obtained in Example 3 ( Figure 2B ) to obtain the accurate water content value; or, substitute the absorbance value obtained into the fitting function y=-9.99394*10 obtained in Example 3 -4 x+0.20587 to calculate and get the accurate water content value, that is, let y=the obtained absorbance value, and the calculated x value is the water content value.

[0097] Fluorescence channel detection: take 0.3mL with a concentration of 0.8×10 -4 mol / L probe L solution in a sample bottle, add 2.7 mL of the test solution, shake well, and let it stand for 20-30 minutes after equilibrium. Measure the fluorescence spectrum performance of the probe L solution to obtain the fluorescence emission intensity value of the test solution at 370 nm; compare the obtained fluorescence emission intensity value with the fluorescence emission intensity-water content standard curve obtained in Example 4 ( Figure 3B ) to obtain an accurate water content value; alternatively, the obtained fluorescence emission intensity value is substituted into the fitting function y = 2.00901x + 94.34215 obtained in Example 4 for calculation to obtain an accurate water content value, so that y = the obtained fluorescence emission intensity value, and the calculated x value is the water content value.

[0098] Example 6

[0099] Six sets of methanol-water solutions with different water contents were prepared as test solutions. The water contents (standard values) of the test solutions are shown in Table 1. The test solutions were tested using the method of Example 5 to obtain water content values, as shown in Table 1. The water content values ​​obtained using the ultraviolet channel are ultraviolet detection values, while the water content values ​​obtained using the fluorescence channel are fluorescence detection values.

[0100] Table 1

[0101]

[0102] According to the data in Table 1, it can be concluded that the error of the UV detection value relative to the standard value is 0.0056-0.0101, and the error of the fluorescence detection value relative to the standard value is 0.0011-0.0112. This shows that the detection method (UV channel and fluorescence channel) provided by the present invention has high detection accuracy.

Claims

1. A method for detecting water in a methanol solvent, characterized in that: The detection method comprises using a detection probe to detect water in a methanol solvent; the structural formula of the detection probe is: ; When the methanol solvent to be tested causes the detection probe solution to change from rose red to light red, it indicates that the methanol solvent to be tested contains 10-100% water; When the methanol solvent to be tested causes the UV-visible absorption spectrum of the detection probe solution to blue shift from 532 nm and is accompanied by a decrease in the absorption peak, it indicates that the methanol solvent to be tested contains 12.27-100% water; When the methanol solvent to be tested enhances the emission peak of the fluorescence emission spectrum of the anhydrous methanol solution of the detection probe at 370 nm, the methanol solvent to be tested contains 0.11-100% water; The detection probe solution is an anhydrous methanol solution of the detection probe; The "10-100%", "12.27-100%", and "0.11-100%" all refer to volume content; The "10-100%", "12.27-100%" and "0.11-100%" do not include 100%.

2. The detection method according to claim 1, characterized in that The methanol solvent to be tested is mixed with the detection probe solution to obtain a detection liquid; the color of the detection liquid is compared with a standard color card to obtain the water content range of the methanol solvent to be tested; the standard color card includes multiple colors and corresponding methanol solvent water contents.

3. The detection method according to claim 2, characterized in that The standard color card is prepared by the following method: adding multiple methanol solvents with different water contents and known water contents into the detection probe solution to obtain multiple standard solutions with different colors. The colors of the multiple standard solutions and the corresponding water contents of the methanol solvents constitute the standard color card.

4. The detection method according to claim 1, characterized in that The methanol solvent to be tested is mixed with the detection probe solution to obtain a detection liquid, and the ultraviolet spectral performance of the detection liquid is measured to obtain the absorbance of the absorption peak of the detection liquid at 500-532nm; the obtained absorbance is compared with the absorbance-water content standard curve to obtain the water content of the methanol solvent to be tested; or, the obtained absorbance is calculated using the absorbance-water content fitting function to obtain the water content of the methanol solvent to be tested.

5. The detection method according to claim 4, characterized in that: Adding a plurality of methanol solvents with different water contents and known water contents into the detection probe solution to obtain a plurality of standard solutions; The ultraviolet spectrum performance of each standard solution is measured to obtain the absorbance of the absorption peak of each standard solution at 500-532nm; and then, an absorbance-water content standard curve is plotted according to the water content of each standard solution and its absorbance at 532nm; or, Adding a plurality of methanol solvents with different water contents and known water contents into the detection probe solution to obtain a plurality of standard solutions; The ultraviolet spectrum performance of each standard solution is measured to obtain the absorbance of the absorption peak of each standard solution at 500-532nm; Then, the water content of each standard solution and the absorbance of its absorption peak at 532 nm were linearly fitted to obtain an absorbance-water content fitting function; The water content of the standard solution refers to the water content of the methanol solvent used to prepare the standard solution.

6. The detection method according to claim 1, characterized in that Adding a methanol solvent to be tested into a detection probe solution to obtain a detection solution, measuring the fluorescence spectrum performance of the detection solution, and obtaining the fluorescence emission intensity of the detection solution at 370 nm; The obtained fluorescence emission intensity is compared with the fluorescence emission intensity-water content standard curve to obtain the water content of the methanol solvent to be tested; or, the obtained fluorescence emission intensity is calculated using the fluorescence emission intensity-water content fitting function to obtain the water content of the methanol solvent to be tested.

7. The detection method according to claim 6, characterized in that The fluorescence emission intensity-water content standard curve can be drawn by the following method: adding a plurality of methanol solvents with different water contents and known water contents to the detection probe solution to obtain a plurality of standard solutions; Determine the fluorescence spectrum performance of each standard solution to obtain the fluorescence emission intensity of each standard solution at 370nm; then draw a fluorescence emission intensity-water content standard curve according to the water content of each standard solution and its fluorescence emission intensity at 370nm; or, The fluorescence emission intensity-water content fitting function can be obtained by the following method: adding a plurality of methanol solvents with different water contents and known water contents to the detection probe solution to obtain a plurality of standard solutions; The fluorescence spectrum performance of each standard solution is measured to obtain the fluorescence emission intensity of each standard solution at 370 nm; then the water content of each standard solution and its fluorescence emission intensity at 370 nm are linearly fitted to obtain a fluorescence emission intensity-water content fitting function; The water content of the standard solution refers to the water content of the methanol solvent used to prepare the standard solution.

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