Background
The prior art discloses that hydrogen peroxide is an important active oxygen substance and has been widely applied to the fields of paper making, textile industry, chemical manufacturing, environmental protection, electronic industry and the like; the data also discloses that hydrogen peroxide can be added into daily necessities such as mouthwash, wound antibacterial agents, cleaning agents, mildew removing agents and the like in a proper amount, and has the functions of cleaning, deodorizing, bleaching and the like; however, studies have shown that excessive hydrogen peroxide is very harmful, and may cause environmental pollution and damage to the ecosystem, as well as human diseases such as cancer and senile dementia. According to statistics, the quantity of hydrogen peroxide generated worldwide is millions of tons, so that the hydrogen peroxide sensor has very important significance in detecting hydrogen peroxide in the environment, and particularly has urgent practical requirements and wide application prospects in real-time rapid and reversible detection. Compared with an electrochemical method, a colorimetric method and the like, the optical hydrogen peroxide sensor has the obvious advantages of anti-interference of an electroactive substance, easiness in miniaturization, capability of remote monitoring and the like. With the aid of a suitable catalyst, hydrogen peroxide can be decomposed into water and oxygen, which, after generation, is automatically separated from the hydrogen peroxide solution without side reactions taking place, so that the concentration of hydrogen peroxide can be determined indirectly by measuring the oxygen production. In 1989, Posch and Wolfbeis (Mikrochim. acta 1989, 1, 41-50.) designed and prepared a novel photochemical hydrogen peroxide multilayer sensing film, and proposed a concept for hydrogen peroxide detection based on the oxygen fluorescence quenching principle, but the response time of the sensor is as long as 5min, and the reversibility and stability are not ideal, so that the sensor is difficult to be applied industrially. Since then, researchers in the industry began to explore how to improve the overall performance of such hydrogen peroxide optical sensors (Sens. actual B-chem.2003, 90, 324; Analyst 2007, 132, 566; 571.), but the response speed was long (about 5min) and reversibility was generally poor. Therefore, response speed and reversibility are important bottleneck problems that restrict the wide application of the optical hydrogen peroxide sensor.
Based on the current state of the art, the inventors of the present application propose to provide a new hydrogen peroxide sensor and a method of manufacturing, in particular a fast response and fully reversible optical hydrogen peroxide sensor.
The invention content is as follows:
the invention aims to provide a novel hydrogen peroxide sensor and a preparation method thereof, in particular to a preparation method of a quick-response and fully reversible optical hydrogen peroxide sensor, aiming at the problems of slow response speed, poor reversibility and the like of the existing optical hydrogen peroxide sensor based on the current situation of the prior art. The optical hydrogen peroxide sensor prepared by the invention has the characteristics of high sensitivity, good stability, high accuracy, quick response, complete reversibility and the like, and can realize quick, complete reversibility and real-time monitoring of hydrogen peroxide.
The fast response and fully reversible optical hydrogen peroxide sensor of the present invention is prepared by the following preparation method, which comprises the steps of:
(1) preparation of oxygen sensitive coating: dissolving a certain amount of oxygen sensing material and a certain amount of luminous complex with oxygen response in an organic solvent to form a uniform solution, and then laying an oxygen sensing film with the thickness of one micron to one millimeter on a certain substrate by means of spraying, spin coating or doctor blade coating.
(2) Preparation of hydrogen peroxide catalytic decomposition coating: firstly, synthesizing a porous material with a large specific surface area by using a nanotechnology, then directly modifying a catalyst with the capability of catalytically decomposing hydrogen peroxide into water and oxygen in the porous material by using an in-situ reduction method, and then wrapping and coating the porous material loaded with the catalyst on the oxygen sensing film prepared in the step (1) through the oxygen sensing material to form a hydrogen peroxide catalytic decomposition coating with the thickness of one micron to one millimeter.
(3) And after the solvent is evaporated and the sensing film is dried, obtaining the optical hydrogen peroxide sensing film with completely reversible response and high response speed, measuring the fluorescence intensity and the fluorescence life change by a photoelectric conversion and phase-locked amplification circuit or a time-resolved fluorescence method, substituting the fluorescence intensity and the fluorescence life change into a Stern-Volmer equation to calculate the concentration of the hydrogen peroxide, and obtaining the optical hydrogen peroxide sensor with rapid response and completely reversible.
In the preparation method of the invention, the raw materials,
in the step (1), the oxygen sensing material is an organic polymer, an organic-inorganic hybrid material (0r mosil) or a Sol-gel (Sol-gel) material, and the oxygen sensing material can have good adhesive force on substrates such as glass, organic films and the like;
the oxygen-responsive phosphorescent luminescent complex is a complex of metals such as aluminum, copper, ruthenium, platinum, palladium, iridium, osmium, europium and the like, which can reversibly quench luminescence thereof, and comprises a metalloporphyrin complex;
the organic solvent can simultaneously dissolve the oxygen sensing material and the organic solvent of the luminescent complex, and includes but is not limited to ethanol, toluene, dichloromethane, acetone and the like or a mixture of a plurality of solvents;
the oxygen sensing membrane is characterized by a thickness that may range from one micron to one millimeter.
In the step (2), the porous material has large specific surface area, the diameter size of the material is between 50nm and 600 mu m, and the size of the pores is between 5nm and 500 nm;
the porous material includes, but is not limited to, silica, organic-inorganic hybrid materials, organic framework Materials (MOF), aerogel materials, etc.;
the hydrogen peroxide catalyst can catalytically decompose hydrogen peroxide into water and oxygen, and the material of the hydrogen peroxide catalyst comprises but is not limited to platinum nanoparticles, gold and silver nanoparticles, platinum-palladium alloy nanoparticles, ruthenium dioxide particles, manganese dioxide particles, peroxidase and the like;
the porous material loaded with the catalyst is a nano catalyst which directly grows in the porous material by adopting an in-situ reduction method for an inorganic catalyst, wherein the catalyst is an inorganic catalyst and is selected from platinum nano particles, gold/silver nano particles, platinum/palladium or platinum-palladium alloy nano particles, ruthenium dioxide particles and/or manganese dioxide particles;
in the invention, the porous material for loading the catalyst has the characteristics of good mechanical stability, difficult loss of the catalyst and the like;
in the present invention, the hydrogen peroxide decomposition coating may have a thickness of from one micron to one millimeter;
in the invention, the hydrogen peroxide sensing film is mainly characterized by at least comprising three parts, namely a supporting substrate, an oxygen sensitive coating and a hydrogen peroxide catalytic decomposition coating.
In the step (3), the hydrogen peroxide sensor is mainly characterized in that the response of the sensor is completely reversible, signals of the sensor in hydrogen peroxide solutions with different concentrations conform to a Stern-Vomer equation, and the response speed of the sensor is high through the high-concentration enrichment catalyst, and the response time is less than 5 minutes;
the measurement method of the fluorescence intensity and the fluorescence lifetime is to measure by a photoelectric conversion, a phase-locked amplification circuit or a time-resolved fluorescence method;
the hydrogen peroxide sensing film has completely reversible response, and the response speed is high and is less than 5 minutes; the stability is good, and the product can be continuously used for more than seven days; the selectivity is good and is not influenced by chloride ions and the like; the response ranged from 0.1 micromoles per liter to 500 millimoles per liter.
The main measurement principle of the optical hydrogen peroxide sensor prepared by the invention is that hydrogen peroxide is rapidly decomposed into water and oxygen by utilizing the hydrogen peroxide catalytic decomposition coating, oxygen molecules are diffused to the oxygen sensitive coating, so that the luminous coordination compound in the oxygen sensitive coating is quenched, the fluorescence intensity or the fluorescence life is reduced, the fluorescence intensity and the fluorescence life change are measured by a photoelectric conversion and phase-locked amplification circuit or a time-resolved fluorescence method, and the indirect detection of the hydrogen peroxide is realized. The method has the characteristics of high sensitivity, good stability, high accuracy, quick response, complete reversibility and the like, can realize quick and complete reversibility of the hydrogen peroxide in real time, can meet urgent practical requirements, and has wide application prospects.
The invention provides a method for preparing a quick-response and completely reversible optical hydrogen peroxide sensor, which can be used for preparing the optical hydrogen peroxide sensor with the characteristics of high sensitivity, good stability, high accuracy, quick response, complete reversibility and the like, and the prepared optical hydrogen peroxide sensor can realize the quick and complete reversibility of hydrogen peroxide and is used for monitoring the hydrogen peroxide in industrial and agricultural production in real time.
Description of the drawings:
FIG. 1 is a schematic diagram of the preparation of a nanosensor of example 1 of the invention.
FIG. 2 is a transmission electron micrograph of a material prepared in example 1 of the present invention; wherein, a transmission electron microscope picture of the prepared porous material; b transmission electron microscopy of the prepared catalyst-loaded porous material.
FIG. 3 is a graph of the sustained response of the optical hydrogen peroxide sensor prepared in example 1 of the present invention to different concentrations of hydrogen peroxide, wherein a. the timescan curve of fluorescence intensity; b. the corresponding Stern-Volmer curve.
FIG. 4 is a graph showing the persistent reversibility of hydrogen peroxide by the optical hydrogen peroxide sensor prepared in example 1 of the present invention.
Detailed Description
The invention is further explained by the specific embodiment in the following with the attached drawings.
Example 1
2.0mg/mL of tetrahydrofuran dye of phosphorescence oxygen probe tetrakis (pentafluorophenyl) porphyrin platinum (II) (PtTFPP) and an oxygen sensing material 5% D4 Hydrogel matrix are mixed uniformly according to the volume ratio of 1: 4 to obtain a red oxygen sensing membrane solution. Coating the oxygen sensing film solution on a high-temperature resistant polyester film (PET film) by a scraper, wherein the thickness of the oxygen sensing film solution is 125 mu m, and the thickness of the oxygen sensing film solution is 3 mu m after the oxygen sensing film solution is dried at room temperature;
dissolving 12mmol of tetraethyl orthosilicate (TEOS) in a mixed solution of cyclohexane (30mL) and 1-pentanol (1.5mL), adding a deionized water solution in which 1.0g of cetylpyridinium hydrate and 0.6g of urea are dissolved, uniformly stirring to obtain a white suspension, reacting for 30 minutes in an oil bath at 25 ℃, and then carrying out hydrothermal reaction for 4 hours at 120 ℃. Naturally cooling to room temperature, centrifugally separating and washing the prepared product, drying in air at room temperature for 24h, and burning at 550 ℃ for 6h to obtain fibrous SiO2And (3) mesoporous microspheres KCC-1. As can be seen from a transmission electron microscope figure 2a, the size of the prepared mesoporous material KCC-1 is 500-600nm, a large number of fibrous mesopores with the aperture of 8-10nm exist, and the mesoporous material has a large specific surface area;
0.4g of the obtained fibrous SiO2Placing the microspheres in a vacuum drying oven, vacuum drying at 120 deg.C for 16h, and naturally cooling to 60 deg.C under vacuum. 2.4mL of hot methanol solution in which 1.9mmol of 3-glycidyloxypropyltrimethoxysilane was dissolved was added to the reaction, and the mixture was stirred in an oil bath at 60 ℃ for 1.5 hours. 2.4mL of hot methanol solution of 0.45mmol of PEI was added to the above reaction mixture and stirred in an oil bath at 60 ℃ for 5 h. The obtained product is centrifugally separated, washed and dried for 12 hours in vacuum at 80 ℃ to obtain white solid KCC-1-PEI. 200mg of the prepared KCC-1-PEI was dispersed in 20mL of deionized water. After ultrasonic dispersion, the mixture was stirred vigorously in an oil bath at 25 ℃ for 10 min. 4mL of deionized water in which 0.257mmol of potassium (II) chloroplatinate was dissolved was then added dropwise, and the reaction mixture was sonicated in an oil bath at 25 ℃ for 30min and stirred in an oil bath at 25 ℃ for 2 h. 2mL of 1M aqueous sodium borohydride solution was added dropwise and stirred in an oil bath at 25 ℃ for 2 h. The obtained product is centrifugally separated, washed and dried for 16 hours at 80 ℃ to obtain the grey solid KCC-1-PEI/PtNPs. As shown in a transmission electron microscope 2b, the prepared Pt nanoparticles are uniformly loaded on the surface of KCC-1-PEI, and are also loaded in a large number of fibrous mesopores, so that the Pt nanoparticles are prevented from being agglomerated, the decomposition and catalysis capability on hydrogen peroxide is greatly improved, and the loss of the Pt nanoparticles in the detection process is effectively prevented;
10mg of KCC-1-PEI/PtNPs powder was dispersed in 500. mu.L of 5% D4 Hydrogel matrix to give a gray film solution. Dispersing 50 μ L of the film solution on a PET film with a thickness of 125 μm, and drying at room temperature to obtain a film with a thickness of 3 μm;
the prepared optical sensor was used for continuous detection of hydrogen peroxide by means of a flow cell device under excitation light of 395 nm. As is evident from FIG. 3a, it has very good sustained response performance to different concentrations of hydrogen peroxide, and as can be seen from FIG. 3b, it responds to the Stern-Volmer equation, with response range of 0.001-10mM, and response time (t)95) Less than 1min, far lower than the response time of about 5min reported at present; as is evident from the continuous detection FIG. 4, the completely reversible detection can be realized, and the long-time continuous detection still has excellent stability, and the result proves that the optical sensor prepared by the invention can be used for the rapid and completely reversible detection of hydrogen peroxide successfully realized and can be used for the online continuous real-time detection.
Example 2
2.0mg/mL of tetrahydrofuran dye of phosphorescence oxygen probe tetrakis (pentafluorophenyl) porphyrin platinum (II) (PtTFPP) and an oxygen sensing material 5% D4 Hydrogel matrix are mixed uniformly according to the volume ratio of 1: 4 to obtain a red oxygen sensing membrane solution. Coating the oxygen sensing film solution on a high-temperature resistant polyester film (PET film) by a scraper, wherein the thickness of the oxygen sensing film solution is 125 mu m, and the thickness of the oxygen sensing film solution is 3 mu m after the oxygen sensing film solution is dried at room temperature;
preparing mesoporous Si02 nano KCC-1 with large specific surface area, and modifying PEI on the surface. 200mg of the prepared KCC-1-PEI was dispersed in 25mL of an aqueous glutaraldehyde solution (1%), stirred at room temperature for 20 minutes, separated by centrifugation, and then centrifugally washed 3 times with 0.01M phosphoric acid buffer solution having a pH of 7.4. Dispersing the obtained nanoparticles in 15mL of 0.5mg mL-1Stirring a 0.01M phosphoric acid buffer solution with pH 7.4 of horseradish peroxidase (HRP) at room temperature overnight, and finally centrifuging and washing to obtain KCC-1-PEI-HRP nanoparticles;
10mg of KCC-1-PEI-HRP nanoparticles were dispersed in 500. mu.L of 5% D4 Hydrogel matrix to obtain a membrane solution. Dispersing 50 μ L of the film solution on a PET film with a thickness of 125 μm, and drying at room temperature to obtain a film with a thickness of 3 μm;
the results show that the prepared optical sensor can be used for continuous detection of hydrogen peroxide by means of a flow cell device under excitation light of 395 nm.
Example 3
2.0mg/mL of phosphorescent oxygen probe tris (4, 7-phenyl-1, 10-phenanthroline) ruthenium (II) bis (ester) (Ru (dpp))3(ClO4)2) The tetrahydrofuran solution and the oxygen sensing material 5% D4 Hydrogel matrix are mixed evenly according to the volume ratio of 1: 4 to obtain the oxygen sensing membrane solution. Coating the oxygen sensing film solution on a PET film by a scraper, wherein the thickness of the PET film is 1.0mm, and the thickness of the PET film is 24 mu m after the PET film is dried at room temperature;
3.0g hexadecyl trimethyl ammonium bromide was added to a 100mL round bottom flask, 60mL deionized water and 0.5mL aqueous triethanolamine (triethanolamine/water (w/w) ═ 1/3) were sequentially added, the mixture was stirred and dissolved at 1000rpm in an oil bath at 60 ℃ for 30 minutes, 16mL cyclohexane was added, the mixture was stirred and stabilized for 5 minutes, 4mL TEOS was rapidly added, and the mixture was stirred and reacted for 6 hours. After the reaction is finished, pouring the solution into ethanol with the same volume, centrifugally separating at the rotating speed of 15000rpm, drying in the air at room temperature for 24 hours, and burning at 550 ℃ for 6 hours to obtain the dendritic Si02 mesoporous microspheres with large specific surface area;
prepared dendritic SiO2Mesoporous microPEI is modified on the surface of the ball, and then 200mg of prepared SiO is added2PEI was dispersed in 20mL of deionized water. After ultrasonic dispersion, the mixture was stirred vigorously in an oil bath at 25 ℃ for 10 min. 4mL of deionized water in which 0.257mmol of potassium (II) chloroplatinate was dissolved was then added dropwise, and the reaction mixture was sonicated in an oil bath at 25 ℃ for 30min and stirred in an oil bath at 25 ℃ for 2 h. 2mL of 1M aqueous sodium borohydride solution was added dropwise and stirred in an oil bath at 25 ℃ for 2 h. Centrifugally separating the obtained product, washing, and drying at 80 ℃ for 16h to obtain gray solid powder, wherein the Pt nano particles are uniformly loaded on the dendritic SiO2The surface of the mesoporous microsphere;
10mg of the powder was dispersed in 500. mu.L of 5% D4 Hydrogel matrix to give a grey film solution. Dispersing the film solution on a PET film with the thickness of 1.0mm, and drying at room temperature to obtain a film with the thickness of 24 μm; the results show that the prepared optical sensor can be used for continuous detection of hydrogen peroxide by means of a flow cell device under excitation light of 395 nm.