Preparation method of probe for detecting hydrazine in wastewater

Abstract

The invention discloses a preparation method of a probe for detecting hydrazine in wastewater, and relates to the technical field of wastewater detection, and the preparation method comprises the following steps: fully mixing 2, 4-dihydroxy benzaldehyde (2.0 g, 14.7 mmol) and 2-naphthylacetic acid (3.0 g, 16.2 mmol) in acetic anhydride (20mL), slowly dropwise adding triethylamine (2mL), under the protection of nitrogen, heating and refluxing for 8 hours, cooling to room temperature, separating out a faint yellow solid, carrying out suction filtration to obtain a crude product, and drying to obtain the hydrazine probe for detecting hydrazine in wastewater. The method comprises the following steps of: weighing 3.75 g of a light yellow solid after recrystallization in ethanol, accurately weighing a probe (TTAM), diluting by using dimethyl sulfoxide (DMSO) to prepare a probe mother solution with the concentration of 1.0 mmol / L, taking 20 mu L of the mother solution during testing, fixing the volume to 2mL by using a DMSO solution (V (DMSO): V (H2O) = 2: 8), accurately extracting a proper amount of N2H4 by using a microsyringe, and diluting by using distilled water to obtain a detection solution with the concentration of 1.0 mmol / L; and the absorbance at the ultraviolet absorption of 333 nm is detected at the position of 350M <-1 >. Cm <-1 >. The probe disclosed by the invention is high in sensitivity, good in selectivity and short in response time, the color of a solution is obviously changed before and after the reaction with N2H4, and naked eye detection of N2H4 is realized.

Description

Technical Field

[0001] The invention relates to the technical field of wastewater detection, in particular to a method for preparing a hydrazine probe for detecting wastewater. Background Art

[0002] Hydrazine hydrate (N2H4), also known as hydrated ammonia, is an extremely important chemical raw material in industrial production. It is used in many fields, but the most important one is used as a propellant for rockets and missiles. Hydrazine is colorless, flammable and highly toxic. It is easily absorbed by the human body through oral administration and skin contact, and can seriously damage various organs and the nervous system of the human body. Various countries have set strict limits on its concentration in drinking water. Therefore, it is particularly important to develop a method with high sensitivity and good reliability, especially for the detection of low-concentration N2H4.

[0003] At present, there are various methods for detecting N2H4. Organic small molecule fluorescent probe method is very popular among researchers due to its high sensitivity, good selectivity, non-invasiveness and high spatiotemporal resolution. Therefore, in recent years, researchers have also developed many fluorescent probes for N2H4 detection. However, most of the reported N2H4 fluorescent probes generally have poor selectivity, low sensitivity, complex synthesis and are easily affected by aggregation quenching, so they are difficult to be applied in practice. Therefore, this application proposes a preparation method for detecting hydrazine probes in wastewater to solve the above technical problems. Summary of the invention

[0004] In order to improve the problems of poor selectivity, low sensitivity, complex synthesis and susceptibility to aggregation quenching that most of the reported N2H4 fluorescent probes mentioned above generally have, the present invention provides a method for preparing a hydrazine probe for detecting wastewater.

[0005] The present invention provides a method for preparing a hydrazine probe for detecting wastewater, which adopts the following technical scheme: A method for preparing a hydrazine probe for detecting wastewater, comprising: 2,4-Dihydroxybenzaldehyde (2.0 g, 14.7 mmol) and 2-naphthylacetic acid (3.0 g, 16.2 mmol) were fully mixed in acetic anhydride (20 mL), and triethylamine (2 mL) was slowly added dropwise.

[0006] Under nitrogen protection, the mixture was heated to reflux for 8 hours and cooled to room temperature. A light yellow solid precipitated and was filtered to obtain a crude product. After recrystallization from ethanol, 3.75 g of a light yellow solid was obtained.

[0007] Accurately weigh the probe (TTAM) and dilute it with dimethyl sulfoxide (DMSO) to prepare a probe stock solution with a concentration of 1.0 mmol / L. During the test, take 20 μL of the stock solution and dilute it to 2 mL with DMSO solution (V(DMSO):V(H2O)=2:8).

[0008] Use a micro-injector to accurately extract an appropriate amount of N2H4 and dilute it with distilled water to a 1.0mmol / L test solution. -1 cm -1 The absorbance at 333 nm was detected by UV absorption.

[0009] Dissolve an appropriate amount of sodium salt directly in deionized water to prepare F − , Cl − Br − 、S2 − 、SO3 2− 、HSO3 − 、SO4 2− 、S2O3 2− 、HCO3 − 、CO3 2− ,Ac − and a stock solution of hydrated hydrazine (20 µM) to prepare anion detection solution.

[0010] The metal ions added are Pd 2+ , Zn 2+ ,Mg 2+ , Fe 3+ , Cu 2+ , Na + , K + , Ca 2+ , Al 3+ , Ni 2+ and hydrated hydrazine were dissolved in deionized water to prepare a cationic detection solution.

[0011] The added interfering small molecules are NH2(CH2)2NH2, CH3(CH2)3NH2, NH2OH, NH3, CO(NH2)2 and hydrated hydrazine, which are dissolved in deionized water to prepare an interfering detection solution.

[0012] Various ions and interfering small molecules were prepared at 400 μM.

[0013] During the test, 0, 10, 20, 30, 40, 50, 60, 70, and 80 μM of the detection solution were added to the probe solution in sequence, and all UV analysis data and fluorescence spectrum data of the probe TTAM were recorded after 120 s.

[0014] In summary, the present invention includes at least one of the following beneficial effects: taking coumarin derivatives as the research object, the compound is prepared by rationally modifying the one-step reaction, and the compound can quickly and effectively identify N2H4. During the experiment, it showed many advantages such as high sensitivity, good selectivity, and short response time. The color of the solution will change significantly before and after the reaction of the probe with N2H4, and the "naked eye detection" of N2H4 can be achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 Schematic diagram of the synthesis route of the probe TTAM of the present invention; Figure 2 Schematic diagram of infrared spectrum of the probe TTAM of the present invention; Figure 3 This is a schematic diagram of the time response of the probe TTAM of the present invention to N2H4; Figure 4 Schematic diagram of the ultraviolet spectrum of the probe TTAM of the present invention reacting with hydrated hydrazine; Figure 5 Schematic diagram of the fluorescence spectrum of the probe TTAM of the present invention reacting with hydrated hydrazine; Figure 6 Schematic diagram of the fitted linear relationship between the fluorescence intensity of the probe TTAM of the present invention and the N2H4 concentration; Figure 7 It is a schematic diagram of the fluorescence spectrum structure of the probe TTAM of the present invention interacting with cations and N2H4; Figure 8 Schematic diagram of the fluorescence spectrum of the probe TTAM of the present invention interacting with anions and N2H4; Fig. 9 Schematic diagram of the fluorescence spectrum of the probe TTAM of the present invention interacting with nitrogen-containing small molecules and N2H4. DETAILED DESCRIPTION

[0016] The following is combined with Figure 1-9 The present invention is described in further detail.

[0017] Example 1, please refer to the attached figure in the specification Figure 1 and 2 A method for preparing a hydrazine probe for detecting wastewater comprises: fully mixing 2,4-dihydroxybenzaldehyde (2.0 g, 14.7 mmol) and 2-naphthylacetic acid (3.0 g, 16.2 mmol) in acetic anhydride (20 mL), slowly dropping triethylamine (2 mL), heating and reflux for 8 hours under nitrogen protection, cooling to room temperature, and precipitation of a light yellow solid. After suction filtration, a crude product is obtained, and after recrystallization in ethanol, 3.75 g of a light yellow solid is obtained.

[0018] Please refer to the attached figure in the instruction manual Figure 3, accurately weigh the probe (TTAM), dilute it with dimethyl sulfoxide (DMSO) to prepare a probe stock solution with a concentration of 1.0mmol / L. During the test, take 20μL of the stock solution and dilute it to 2mL with DMSO solution (V(DMSO):V(H2O)=2:8). Use a microinjector to accurately extract an appropriate amount of N2H4 and dilute it with distilled water to a 1.0mmol / L test solution. And at ℇ=350M -1 cm -1 The absorbance at 333 nm was detected by UV absorption.

[0019] Dissolve an appropriate amount of sodium salt directly in deionized water to prepare F − , Cl − Br − 、S2 − 、SO3 2− 、HSO3 − 、SO4 2− 、S2O3 2− 、HCO3 − 、CO3 2− ,Ac − and hydrated hydrazine stock solution (20µM) to prepare anion detection solution. The metal ions added were pd 2+ , Zn 2+ ,Mg 2+ , Fe 3+ , Cu 2+ , Na + , K + , Ca 2+ , Al 3+ , Ni 2+ The cationic detection solution was prepared by dissolving hydrated hydrazine in deionized water. The interfering small molecules added were NH2(CH2)2NH2, CH3(CH2)3NH2, NH2OH, NH3, CO(NH2)2 and hydrated hydrazine in deionized water to prepare the interfering detection solution.

[0020] Various ions and interfering small molecules were prepared at 400 μM.

[0021] During the test, 0, 10, 20, 30, 40, 50, 60, 70, and 80 μM of the detection solution were added to the probe solution in sequence, and all UV analysis data and fluorescence spectrum data of the probe TTAM were recorded after 120 s.

[0022] Please refer to the attached figure in the instruction manual Figure 4-6 Through multiple experiments, the optimal test pH was determined to be 8. When 20µM N2H4 was added to TTAM, the reaction could completely occur and reach equilibrium within 120s. Therefore, the subsequent fluorescence test experiments were tested and recorded after 120s.

[0023] Please refer to the attached figure in the instruction manual Figure 3 ,After 120s, the fluorescence intensity of the added N2H4 probe reached the highest and remained relatively stable.

[0024] Please refer to the attached figure in the instruction manual Figure 3 , considering the influence of solvent toxicity, DMSO / H2O (v / v, 2 / 8) system of TTAM was used as the solvent for the following experiments.

[0025] Please refer to the attached figure in the instruction manual Figure 4 , UV-visible spectra when different N2H4 solutions are added to the main probe solution. From the spectrum, it can be seen that the main body has a maximum absorption at 333nm. With the addition of different N2H4 concentrations, the absorption value at 333nm decreases significantly, and a new absorption peak appears at 406nm, which increases with the increase of N2H4 concentration. At the same time, the color of the solution gradually changes from colorless to yellow-green.

[0026] Please refer to the attached figure in the instruction manual Figure 5 , Fluorescence spectrum intensity diagram of different concentrations of N2H4 added to the probe solution. The probe concentration configured during the experiment was 10μM and the excitation wavelength was 333nm. It can be seen from the figure that there is a maximum emission peak at 480nm. With the addition of hydrazine hydrate, the emission peak intensity gradually increases. Under the irradiation of ultraviolet light with an excitation wavelength of 365nm, the fluorescence color changes from light green to blue-green. The color change can be used to determine the presence of N2H4 by the naked eye.

[0027] Please refer to the attached figure in the instruction manual Figure 6 In order to further study the effect of the probe on N2H4, the probe TTAM was treated with different concentrations of N2H4, the fluorescence response of the probe TTAM to different concentrations of N2H4 was studied, and the fluorescence intensity was plotted as a function of increasing N2H4 concentration at 333 nm.

[0028] Please refer to the attached figure in the instruction manual Figure 6 When the concentration of N2H4 was between 0 and 40 μM, the fluorescence intensity of the probe showed a good linear relationship with the concentration of N2H4. After data fitting, the linear regression equation y = 264.8 + 14.08x (linear correlation coefficient R 2 =0.977), according to the minimum detection concentration calculation formula C of general instruments m =3 σ bi / m, and the detection limit was calculated to be 0.53 μM. The above results show that TTAM has a high sensitivity.

[0029] In order to further study the selectivity of the probe for N2H4 recognition, it is necessary to perform fluorescence emission spectroscopy analysis on the added relevant ions. Therefore, under the same test conditions, the selective response of TTAM to various anions, cations and interfering small molecules was accurately studied.

[0030] Please refer to the attached figure in the instruction manual Figure 7 , The fluorescence spectra of different metal cations and N2H4 after reacting with the probe TTAM. It can be seen from the figure that the cations have basically no effect on the probe, and there is basically no fluorescence effect. After adding N2H4, the fluorescence intensity is significantly enhanced, and the fluorescence is enhanced by more than 10 times, which is enough to show that the above cations will not interfere with the detection of hydrated hydrazine.

[0031] Please refer to the attached figure in the instruction manual Figure 8 From the fluorescence selectivity diagram of the probe to different anions, it can be seen that the effect of anions on the probe is similar to that of cations, and there is basically no fluorescence effect. Only when N2H4 is added, the fluorescence intensity can be significantly enhanced. Please refer to the attached figure in the instruction manual Fig. 9 From the fluorescence selectivity diagram of different nitrogen-containing interfering small molecules, it can be seen that when only hydroxylamine hydrochloride is added, it has a slight effect on the probe body but does not affect the detection of hydrated hydrazine, and the effect on other interfering small molecules is even smaller, which is enough to prove that the probe exhibits good anti-interference ability.

[0032] The above are all preferred embodiments of the present invention, and are not intended to limit the protection scope of the present invention. Therefore, any equivalent changes made based on the structure, shape, and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing a hydrazine probe for detecting wastewater, characterized in that: include, S1: 2,4-dihydroxybenzaldehyde (2.0 g, 14.7 mmol) and 2-naphthylacetic acid (3.0 g, 16.2 mmol) were fully mixed in acetic anhydride (20 mL), and triethylamine (2 mL) was slowly added dropwise; S2: When performing step S1, the mixture was heated under reflux for several hours under the protection of a chemically inactive gas, cooled to room temperature, and a light yellow solid was precipitated. After filtration, a crude product was obtained, and after recrystallization from an organic solvent, 3.75 g of a light yellow solid was obtained, thereby preparing 3-(2-naphthyl)-7-acetoxycoumarin (TTAM); S3: Accurately weigh the probe (TTAM) and dilute it with dimethyl sulfoxide (DMSO) to prepare the probe stock solution; S4: Pipette 20 μL of the stock solution and dilute to 2 mL with DMSO solution; S5: Use a micro-injector to accurately extract an appropriate amount of N2H4 and dilute it with distilled water to a 1.0mmol / L test solution, and at ℇ=350M -1 cm -1 The absorbance at 333 nm of ultraviolet absorption was detected; S6: dissolving an appropriate amount of sodium salt directly in deionized water to prepare a variety of selective detection solutions; S7: The volume of various selective detection solutions is 400 μM; S8: During the test, 0, 10, 20, 30, 40, 50, 60, 70, and 80 μM of the detection solution were added to the probe solution in sequence, and all the UV analysis data and fluorescence spectrum data of the probe TTAM were recorded after 120 seconds.

2. The method for preparing a hydrazine probe for detecting wastewater according to claim 1, characterized in that: The chemically inactive gas is nitrogen.

3. The method for preparing a hydrazine probe for detecting wastewater according to claim 1, characterized in that: The organic solvent is ethanol liquid.

4. The method for preparing a hydrazine probe for detecting wastewater according to claim 1, characterized in that: The concentration of the probe mother solution is 1.0 mmol / L.

5. The method for preparing a hydrazine probe for detecting wastewater according to claim 1, characterized in that: The volume ratio in the DMSO solution is V(DMSO):V(H2O)=2:

8.

6. The method for preparing a hydrazine probe for detecting wastewater according to claim 1, characterized in that: When preparing the selective detection solution, F − , Cl − Br − 、S2 − 、SO3 2− 、HSO3 − 、SO4 2− 、S2O3 2− 、HCO3 − 、CO3 2− ,Ac − and a stock solution of hydrated hydrazine (20 µM) to prepare anion detection solution.

7. The method for preparing a hydrazine probe for detecting wastewater according to claim 1, characterized in that: When preparing the selective detection solution, pd 2+ , Zn 2+ ,Mg 2+ , Fe 3+ , Cu 2+ , Na + , K + , Ca 2+ , Al 3+ , Ni 2+ and hydrated hydrazine were dissolved in deionized water to prepare a cationic detection solution.

8. The method for preparing a hydrazine probe for detecting wastewater according to claim 1, characterized in that: When preparing the selective detection liquid, NH2(CH2)2NH2, CH3(CH2)3NH2, NH2OH, NH3, CO(NH2)2 and hydrated hydrazine are dissolved in deionized water in sequence to prepare an interference detection liquid.

9. The method for preparing a hydrazine probe for detecting wastewater according to claim 1, characterized in that: When the test was performed, the pH value was controlled to be 8.

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