Preparation method and application of a fluorescence sensor for detecting hydrogen phosphate

Abstract

The application relates to a preparation method of a fluorescence sensor for detecting hydrogen phosphate and application thereof, and relates to the field of analysis and detection, in particular to a preparation method of a fluorescence sensor and application thereof in hydrogen phosphate detection. The application solves the problems of low sensitivity and poor anti-interference in the existing fluorescence method for detecting hydrogen phosphate. The preparation method of the fluorescence sensor is as follows: after a coumarin Schiff base compound L is combined with copper ions in an ethanol solution, the fluorescence sensor is prepared. The prepared fluorescence sensor has excellent performance, can realize specific recognition of hydrogen phosphate in the ethanol solution, has good anti-interference ability in the detection process, and can realize high-sensitivity detection of hydrogen phosphate. The application can be used in the field of hydrogen phosphate detection.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of hydrogen phosphate detection, in particular to a preparation method of a fluorescent probe and application thereof in hydrogen phosphate detection. BACKGROUND

[0002] Hydrogen phosphate is an important nutritional supplement for organisms, for example, calcium hydrogen phosphate is a main component of fertilizer, and potassium hydrogen phosphate can be used in medicine to treat hypokalemia and nutritional agents for trauma patients. However, the large use of phosphate fertilizer and industrial wastewater generated in the production process of phosphorus-containing products can cause eutrophication of natural water bodies. Therefore, effective monitoring of hydrogen phosphate in the environment has important practical significance.

[0003] There are various existing hydrogen phosphate detection technologies, mainly based on national standard phosphorus molybdenum blue method, ion chromatography, colorimetric method, spectrophotometric method, etc. However, these methods need to use complex equipment in the detection process, are complicated to operate, require high operating personnel, and have long test periods, so that online continuous detection of hydrogen phosphate cannot be realized. Fluorescence analysis method has the advantages of high sensitivity, good selectivity, simple operation, short response time, visualization and online continuous detection, etc., and is outstanding among numerous detection methods, which has attracted widespread attention of domestic and foreign researchers. However, there are few reports on fluorescent sensors for detecting hydrogen phosphate. According to the substitution displacement principle, the present application designs and prepares a novel coumarin Schiff base compound L and copper ion complex as a fluorescent sensor to realize specific recognition of hydrogen phosphate. The fluorescent sensor prepared in the present application has the advantages of good selectivity, strong anti-interference, high sensitivity and simple operation in the process of recognizing hydrogen phosphate. SUMMARY

[0004] The present application aims to solve the problems of low sensitivity and poor anti-interference of the existing fluorescent method for detecting hydrogen phosphate, and provides a preparation method and application of a fluorescent sensor for detecting hydrogen phosphate.

[0005] The preparation method of the fluorescent sensor for detecting hydrogen phosphate is as follows: in an ethanol solution, a coumarin Schiff base compound L reacts with copper ions to form a L-Cu complex, and the fluorescent sensor is obtained. 2+

[0006] Further, the molecular structure of the coumarin Schiff base compound L is as follows:

[0007]

[0008] Further, the synthesis route of the above-mentioned coumarin Schiff base compound L is as follows:

[0009]

[0010] ​Further, the preparation method of the coumarin Schiff base compound L is that 7-(diethylamino) coumarin-3-formylhydrazine is condensed with croton aldehyde to prepare the coumarin Schiff base compound L.

[0011] The fluorescent sensor prepared by the application can realize the fluorescence response recognition of hydrogen phosphate.

[0012] Further, the detection limit of the fluorescent sensor for hydrogen phosphate is as low as 7.1*10 -8 mol / L.

[0013] Further, the fluorescent sensor can resist the interference of NO2 - , CO3 2- , SO3 2- , I-, Br - , F - , HCO3 - , SO4 2- , NO3 - , Cl - , CH3COO - , Cr2O7 2- , S2O3 2- and P2O7 4- in the detection of hydrogen phosphate.

[0014] In the actual detection of a sample containing hydrogen phosphate, the sample can be pretreated by centrifugation and filtration to remove solid particle impurities.

[0015] Principle of the application:

[0016] The coumarin Schiff base compound L prepared by the application can form a complex with copper ions in the structure and has no fluorescence; after the addition of hydrogen phosphate in the complex system, the hydrogen phosphate can coordinate with copper ions and replace the copper ions, so that the compound L restores the monomer structure and initiates fluorescence enhancement, so as to realize the "off-on" detection of hydrogen phosphate.

[0017] Compared with the prior art, the application has the following beneficial effects:

[0018] 1) The fluorescent sensor prepared by the application is simple to operate and low in cost, and can realize the fluorescence detection of hydrogen phosphate without the need of expensive large-scale instruments and complex sample pretreatment.

[0019] 2) The fluorescent sensor prepared by the application can not be interfered by NO2 - , CO3 2- , SO3 2- , I - , Br - , F - , HCO3- , SO4 2- , NO3 - , Cl-, CH3COO - , Cr2O7 2- , S2O3 2- and P2O7 4- interference, and has good anti-interference ability.

[0020] 3) In 0-10 muM, the fluorescence intensity has good linear relationship with the concentration of hydrogen phosphate, and the detection limit of the fluorescence sensor for hydrogen phosphate is as low as 7.1*10 -8 mol / L, so that trace qualitative and quantitative detection of hydrogen phosphate is realized. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 The present application discloses a preparation method of coumarin Schiff base compound L 1 H NMR spectrum

[0022] Figure 2 The present application discloses a preparation method of coumarin Schiff base compound L IR spectrum

[0023] Figure 3 Selectivity of the fluorescence sensor to recognize anion

[0024] Figure 4 Effect of coexisting anions on the recognition of hydrogen phosphate by the fluorescence sensor

[0025] Figure 5 Linear relationship diagram of fluorescence response of the fluorescence sensor to hydrogen phosphate with different concentrations

[0026] Figure 6 Job's plot curve of the fluorescence sensor to hydrogen phosphate DETAILED DESCRIPTION

[0027] The technical scheme of the present application is not limited to the following specific embodiments, and any combination of the specific embodiments is also included.

[0028] Specific embodiment one: a preparation method of the fluorescence sensor for detecting hydrogen phosphate, which comprises the following steps: in an ethanol solution, coumarin Schiff base compound L reacts with copper ions to form L-Cu 2+ complex, i.e. the fluorescence sensor; the molecular structure of the coumarin Schiff base compound L is as follows:

[0029]

[0030] Specific embodiment two: the preparation method of the coumarin Schiff base compound L is that 7-(diethylamino) coumarin-3-formylhydrazine is condensed with crotonaldehyde to prepare the coumarin Schiff base compound L.

[0031] Specific embodiment three: the application of the fluorescent sensor in the identification of hydrogen phosphate in the embodiment.

[0032] Specific embodiment four: the difference between the embodiment and the specific embodiment three is that the detection limit of the fluorescent sensor for hydrogen phosphate is as low as 7.1 x 10 -8 mol / L. The others are the same as the specific embodiment three.

[0033] Specific embodiment five: the difference between the embodiment and the specific embodiment three or four is that the fluorescent sensor can resist the interference of NO2 - , CO3 2- , SO3 2- , I - , Br - , F - , HCO3 - , SO4 2- , NO3 - , Cl - , CH3COO - , Cr2O7 2- , S2O3 2- and P2O7 4- in the detection of hydrogen phosphate. The others are the same as the specific embodiment three or four.

[0034] In the actual detection of the sample containing hydrogen phosphate, the sample can be pretreated by centrifugation and filtration to remove solid particle impurities.

[0035] The embodiments of the application are described in detail below. The following embodiments are implemented on the premise of the technical scheme of the application, and detailed implementation schemes and specific operation processes are given, but the protection scope of the application is not limited to the following embodiments.

[0036] Embodiment 1: the preparation method of the coumarin Schiff base compound L in the embodiment is carried out according to the following steps:

[0037] 7-(diethylamino) coumarin-3-formylhydrazine (0.2 g, 0.73 mmol) is dissolved in 25 mL of anhydrous ethanol, and the solution is stirred to be clear by heating. Crotonaldehyde (0.141 g, 2 mmol) is added to the reaction system, and the reaction is completed by reflux. Most of the solvent is concentrated, and the reaction solution is frozen overnight. Yellow solid is obtained by suction filtration, washed with ice ethanol, and dried to obtain yellow solid coumarin Schiff base compound L with a yield of 78%. 1H NMR (300 MHz, DMSO-d6) δ: 11.42 (s, 1H), 8.72 (s, 1H), 8.01-7.99 (m, 1H), 7.71 (d, J = 9.0 Hz, 1H), 6.83 (dd, J = 9.0, 2.4 Hz, 1H), 6.65 (d, J = 2.3 Hz, 1H), 6.26-6.24 (m, 2H), 3.50 (q, J = 6.0 Hz, 4H), 1.87 (d, J = 6.0 Hz, 3H), 1.15 (t, J = 7.0 Hz, 6H) ppm. IR (KBr) v: 3435, 2831, 2709, 1687, 1612, 1513, 1363, 1188, 1134, 775 cm -1 ; compound L 1 HNMR spectrum, IR spectrum are shown in Figure 1 , 2 .

[0038] Example 2: Preparation of fluorescent sensor, according to the following steps:

[0039] Accurately weigh 3.3 mg of coumarin Schiff base compound L to prepare a 1.0 x 10 -2 mol / L ethanol solution A; take 50 μL of solution A with a concentration of 1.0 x 10 -2 mol / L, add 1 eq. of copper nitrate, and dilute with anhydrous ethanol to 50 mL. After incubation for 3 min, the fluorescent sensor is obtained.

[0040] Example 3: Selective recognition of anions by fluorescent sensor, according to the following steps:

[0041] Add 1 eq. of NO2 - , CO3 2- , SO3 2- , HPO4 2- , I - , Br - , F - , HCO3 - , SO4 2- , NO3 - , Cl - , CH3COO - , Cr2O7 2- , S2O3 2- , P2O7 4- to the fluorescent sensor solution in turn. Under the action of 484 nm excitation light, the fluorescence intensity is measured, and the results are shown in Figure 3 . After the addition of hydrogen phosphate, the fluorescence of the system is significantly enhanced, while the addition of other anions does not cause significant changes in fluorescence intensity. The fluorescent sensor can achieve selective recognition of hydrogen phosphate.

[0042] Example 4: Anti-interference of the fluorescent sensor for identifying hydrogen phosphate, according to the following steps:

[0043] In the fluorescent sensor solution, 1 eq. of NO2 - , CO3 2- , SO3 2- , HPO4 2- , I - , Br - , F - , HCO3 - , SO4 2- , NO3 - , Cl-, CH3COO-, Cr2O7 2- , S2O3 2- , P2O7 4- was added in turn under the action of 484 nm excitation light, and the fluorescence intensity was recorded, then 1 eq. of hydrogen phosphate was added in turn, and the fluorescence intensity change was observed and recorded, and the results are shown in Figure 4 . In the presence of other coexisting anions, the fluorescence can still be enhanced after the addition of hydrogen phosphate, and other anions have no interference with the identification of hydrogen phosphate by the fluorescent sensor.

[0044] Example 5: Detection limit of the fluorescent sensor for hydrogen phosphate, according to the following steps:

[0045] In the fluorescent sensor, 0.3 μL of 1 × 10 -2 mol / L aqueous solution of sodium hydrogen phosphate was added in turn, and the fluorescence intensity was measured, and the results are shown in Figure 5 . When the concentration of hydrogen phosphate is within 0 μM-10 μM, the fluorescence intensity is continuously enhanced with the increase of the concentration of hydrogen phosphate, and shows a good linear relationship with the concentration of hydrogen phosphate, and the fitting equation is y = 40.21x + 74.6, R 2 = 0.996. According to the calculation formula 3σ / k of the detection limit, the detection limit of the fluorescent sensor for hydrogen phosphate is calculated to be 7.1 × 10 - 8 mol / L.

[0046] Example 6: Action ratio of the fluorescent sensor and hydrogen phosphate, according to the following steps:

[0047] The total concentration of the fluorescent sensor and hydrogen phosphate in the system was kept at 1 × 10 -5 mol / L, the fluorescence intensity was determined by changing the equivalent ratio of the two, and the Job’s Plot curve was drawn, and the results are shown in Figure 6 . When the molar fraction of hydrogen phosphate is 0.50, the fluorescence intensity appears an inflection point, which indicates that the action ratio of the fluorescent sensor and hydrogen phosphate is 1:1.

[0048] Example 7: Application of the fluorescent sensor in detecting hydrogen phosphate in actual water samples

[0049] The laboratory tap water was selected and pretreated: the water sample was centrifuged at a speed of 12000 rpm for 10 min, filtered by a 0.45 μm filter, and sodium hydrogen phosphate solutions with concentrations of 2 μmol / L, 4 μmol / L, 6 μmol / L and 8 μmol / L were prepared. The above sodium hydrogen phosphate solutions with different concentrations were added into the fluorescent sensor, under the action of 484 nm excitation light, the fluorescence emission peak intensity value of the system at 438 nm was measured, and the concentration of the sodium hydrogen phosphate solution to be detected was calculated by bringing it into the following equation. The detection results are shown in Table 1.

[0050] Y = 40.21 × X + 74.6 wherein, X is the concentration of sodium hydrogen phosphate, and Y is the fluorescence emission peak intensity value.

[0051] Table 1: Results of detecting hydrogen phosphate in actual water samples by the fluorescent sensor

[0052] Actual water sample Amount added / μM Detection limit / μM Recovery / % RSD / %, n = 3 Blank / / / 0.82 1 2 1.995 99.75 2.74 2 4 3.922 98.05 0.70 3 6 5.920 98.67 0.59 4 8 7.944 99.30 0.42

[0053] As can be seen from Table 1, the recovery rate of hydrogen phosphate in the actual water sample is 98.05% to 99.75%, the relative standard deviation is 0.42% to 2.74%, and the measured concentration of hydrogen phosphate has a very small error with the corresponding standard concentration. These results show that the fluorescent sensor prepared by the present application has good accuracy and good practical performance in detecting hydrogen phosphate in actual water samples.

Claims

1. The application of a coumarin Schiff base compound L complexed with copper ions as a fluorescent sensor for the detection of hydrogen phosphate, characterized in that... The preparation method of this fluorescence sensor includes the following steps: In an ethanol solution, coumarin Schiff base compound L reacts with copper ions to form L-Cu. 2+ The complex yields the fluorescent sensor, and the molecular structure of the coumarin Schiff base compound L is as follows: This fluorescence sensor is not intended for disease diagnosis or treatment.

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