阅读说明：本技术 一种高精度检测挥发性有机化合物的检测方法 (Detection method for detecting volatile organic compounds with high precision ) 是由 张维 于 2020-04-22 设计创作，主要内容包括：本发明公开了一种高精度检测挥发性有机化合物的检测方法,通过制备铈掺杂介孔分子筛,再对其依次进行氨丙基改性、苝-3,4,9,10-四羧酸二酐接枝和十八硫醇修饰,经封装后制备了挥发性有机化合物检测膜；并利用该检测膜对不同浓度的挥发性有机化合物表现出的荧光强度差异,建立挥发性有机物浓度与检测膜荧光强度间的标准曲线,从而实现对挥发性有机化合物的高精度检测。通过上述方式,本发明能够利用分子筛中丰富的孔道结构对挥发性有机化合物进行高效吸脱附,并利用苝-3,4,9,10-四羧酸二酐的荧光效应实现对挥发性有机物的定量检测,再结合各基团间的协同作用,有效提高检测的灵敏度、准确度及稳定性,应用范围较广。(The invention discloses a detection method for detecting a volatile organic compound with high precision, which comprises the steps of preparing a cerium-doped mesoporous molecular sieve, sequentially carrying out aminopropyl modification, perylene-3, 4,9, 10-tetracarboxylic dianhydride grafting and octadecanethiol modification on the cerium-doped mesoporous molecular sieve, and preparing a volatile organic compound detection film after packaging; and establishing a standard curve between the concentration of the volatile organic compounds and the fluorescence intensity of the detection membrane by using the fluorescence intensity difference of the detection membrane to the volatile organic compounds with different concentrations, thereby realizing the high-precision detection of the volatile organic compounds. Through the mode, the volatile organic compound can be efficiently adsorbed and desorbed by utilizing rich pore channel structures in the molecular sieve, the quantitative detection of the volatile organic compound is realized by utilizing the fluorescence effect of the perylene-3, 4,9, 10-tetracarboxylic dianhydride, and the detection sensitivity, accuracy and stability are effectively improved by combining the synergistic effect among all groups, so that the application range is wide.)

1. A detection method for detecting volatile organic compounds with high precision is characterized by comprising the following steps:

s1, preparing a cerium-doped mesoporous molecular sieve by a hydrothermal reaction method;

s2, uniformly dispersing the cerium-doped mesoporous molecular sieve obtained in the step S1 in isopropanol, adding a predetermined amount of 3-aminopropyltrimethoxysilane, fully reacting for 8-10 hours at 85-95 ℃, and after the reaction liquid is cooled to room temperature, sequentially centrifuging, washing and drying the reaction liquid to obtain an aminopropyl modified cerium-doped mesoporous molecular sieve;

s3, mixing perylene-3, 4,9, 10-tetracarboxylic dianhydride with the aminopropyl modified cerium-doped mesoporous molecular sieve obtained in the step S2 according to a preset mass ratio, uniformly dispersing the mixture in isopropanol, fully reacting at room temperature for 10-12 hours, and then sequentially centrifuging, washing and drying the reaction liquid to obtain the perylene-3, 4,9, 10-tetracarboxylic dianhydride grafted molecular sieve;

s4, dissolving octadecanethiol in isopropanol, adding the perylene-3, 4,9, 10-tetracarboxylic dianhydride grafted molecular sieve obtained in the step S3, stirring uniformly, and adding the mixture into N²Heating to 90-95 ℃ in the atmosphere, fully reacting for 8-10 h, cooling the reaction liquid to room temperature, and then sequentially centrifuging, washing and drying the reaction liquid to obtain the perylene-3, 4,9, 10-tetracarboxylic dianhydride grafted molecular sieve modified by octadecanethiol;

s5, uniformly mixing the octadecanethiol-modified perylene-3, 4,9, 10-tetracarboxylic dianhydride grafted molecular sieve obtained in the step S4, ethoxylated bisphenol A diacrylate, a photoinitiator and a surface wetting agent according to a preset mass ratio, uniformly coating the mixture on a glass substrate, and obtaining a volatile organic compound detection film after ultraviolet irradiation;

s6, placing the volatile organic compound detection films obtained in the step S5 in volatile organic compound standard steam to be detected with different concentrations, performing fluorescence detection on the volatile organic compound detection films, and drawing a standard curve of fluorescence intensity changing along with the concentration of the volatile organic compound steam; and then placing the volatile organic compound detection film in steam to be detected, performing fluorescence detection, and calculating the concentration of the volatile organic compound to be detected in the steam to be detected according to the standard curve.

2. The method for detecting a volatile organic compound with high accuracy according to claim 1, wherein: in step S1, the hydrothermal reaction method for preparing the cerium-doped mesoporous molecular sieve comprises the following steps:

mixing ethyl orthosilicate and deionized water, stirring at 35 ℃ for 40min, sequentially adding sodium hydroxide, sodium fluoride and cerium nitrate, and fully stirring for 60min to obtain a mixed solution; adding hexadecyl trimethyl ammonium bromide into the mixed solution, stirring for 60min, placing the reaction solution into a high-pressure kettle, heating at 120 ℃ for 24h, and sequentially filtering, washing, drying and roasting the product to obtain a cerium-doped mesoporous molecular sieve; the roasting treatment temperature is 550 ℃, and the roasting time is 4 hours.

3. The method for detecting a volatile organic compound with high accuracy according to claim 2, wherein: in the step of preparing the cerium-doped mesoporous molecular sieve by the hydrothermal reaction method, the molar ratio of the ethyl orthosilicate to the deionized water to the sodium hydroxide to the sodium fluoride to the cerium nitrate to the hexadecyl trimethyl ammonium bromide is 1:62:0.5:0.1 (0.005-0.04) to 0.65.

4. The method for detecting a volatile organic compound with high accuracy according to claim 1, wherein: in step S2, the mass ratio of the cerium-doped mesoporous molecular sieve to 3-aminopropyltrimethoxysilane is 2: 1.

5. The method for detecting a volatile organic compound with high accuracy according to claim 1, wherein: in step S3, the preset mass ratio of the perylene-3, 4,9, 10-tetracarboxylic dianhydride to the aminopropyl-modified cerium-doped mesoporous molecular sieve is (2-4): 5.

6. The method for detecting a volatile organic compound with high accuracy according to claim 1, wherein: in step S4, the mass ratio of the octadecanethiol to the perylene-3, 4,9, 10-tetracarboxylic dianhydride grafted molecular sieve is 3: 2.

7. The method for detecting a volatile organic compound with high accuracy according to claim 1, wherein: in step S5, the predetermined mass ratio of the octadecanethiol-modified perylene-3, 4,9, 10-tetracarboxylic dianhydride grafted molecular sieve to the ethoxylated bisphenol a diacrylate, the photoinitiator, and the surface wetting agent is 92.5:5:2: 0.5.

8. The method for detecting a volatile organic compound with high accuracy according to claim 1, wherein: in step S5, the photoinitiator is 2,4, 6-trimethylbenzoyl-diphenylphosphine oxide, and the surfactant is polyether-modified polydimethylsiloxane.

9. The method for detecting a volatile organic compound with high accuracy according to claim 1, wherein: in step S5, the thickness of the VOC detection film is 8-12 μm.

10. The method for detecting a volatile organic compound with high accuracy according to claim 1, wherein: in step S6, the volatile organic compound to be tested includes, but is not limited to, one of methanol, formaldehyde, dimethylformamide, or tetrahydrofuran.

Technical Field

The invention relates to the technical field of volatile organic compound detection, in particular to a detection method for detecting a volatile organic compound with high precision.

Background

With the development of the scientific and technological level and the industrial technology, products such as gasoline, rubber, pesticides, plastic products and the like bring convenience to human life, and harmful gas generated in the production process of the products also harms the environment and the human health. The volatile organic compound is an important item of the above harmful gases, and generally refers to various organic compounds having a boiling point of 50 to 260 ℃ at normal temperature, mainly includes hydrocarbons, oxygen hydrocarbons, halogen-containing hydrocarbons, nitrogen hydrocarbons, sulfur hydrocarbons, low-boiling polycyclic aromatic hydrocarbons and the like, and is a class of organic pollutants which are ubiquitous in the air and have complex compositions, and chemical properties carried by the volatile organic compound show certain toxicity and irritation, and may have carcinogenic effect, thereby threatening the health of people. Therefore, in order to improve the quality of the ambient air and guarantee the health of people, the method has important significance for detecting the volatile organic compounds in the environment.

At present, gas chromatography or gas chromatography-mass spectrometry is commonly adopted for detecting volatile organic compounds, and both methods have the advantages of high sensitivity, high analysis speed and the like, but generally require a complex sample pretreatment process, are complex in operation, complex in technology and expensive in equipment, have higher requirements on operators and detection environment, and cause the application of the methods to be limited. In addition, a colorimetric tube detection method can be adopted for detecting the volatile organic compound, the method utilizes chemical reaction between gas to be detected and a chromogenic substance to establish a linear relation between the gas concentration and the chromogenic concentration, but the detection result is not accurate enough due to low sensitivity of the currently commonly used chromogenic substance to the volatile organic compound to be detected.

Patent publication No. CN110987822A provides a method for detecting volatile organic compounds by preparing a nickel oxide film having an inverse opal structure and estimating the kind of volatile organic compounds using the different colors of the nickel oxide film corresponding to the saturated vapor of different volatile organic compounds. However, the nickel oxide film prepared by the method has a limited response effect with volatile organic compounds, and trace volatile organic compounds may hardly cause obvious color change, so that the method has low sensitivity when detecting volatile organic compounds, is difficult to accurately judge the type and concentration of the trace volatile organic compounds, has insufficient detection precision, and is limited in practical application.

In view of the above, it is still necessary to research a detection method for detecting volatile organic compounds, so as to improve the sensitivity and accuracy of the detection process and achieve high-precision detection of the volatile organic compounds.

Disclosure of Invention

The invention aims to solve the problems and provides a detection method for detecting volatile organic compounds with high precision, which comprises the steps of preparing a cerium-doped mesoporous molecular sieve, sequentially carrying out aminopropyl modification, perylene-3, 4,9, 10-tetracarboxylic dianhydride grafting and octadecanethiol modification on the cerium-doped mesoporous molecular sieve, and packaging to obtain a detection film with excellent adsorption and desorption properties and high sensitivity on the volatile organic compounds; and establishing a standard curve between the concentration of the volatile organic compounds and the fluorescence intensity of the detection membrane by using the fluorescence intensity difference of the detection membrane to the volatile organic compounds with different concentrations, thereby realizing the high-precision detection of the volatile organic compounds.

In order to achieve the above object, the present invention provides a detection method for detecting a volatile organic compound with high accuracy, comprising the steps of:

s1, preparing a cerium-doped mesoporous molecular sieve by a hydrothermal reaction method;

s2, uniformly dispersing the cerium-doped mesoporous molecular sieve obtained in the step S1 in isopropanol, adding a predetermined amount of 3-aminopropyltrimethoxysilane, fully reacting for 8-10 hours at 85-95 ℃, and after the reaction liquid is cooled to room temperature, sequentially centrifuging, washing and drying the reaction liquid to obtain an aminopropyl modified cerium-doped mesoporous molecular sieve;

s3, mixing perylene-3, 4,9, 10-tetracarboxylic dianhydride with the aminopropyl modified cerium-doped mesoporous molecular sieve obtained in the step S2 according to a preset mass ratio, uniformly dispersing the mixture in isopropanol, fully reacting at room temperature for 10-12 hours, and then sequentially centrifuging, washing and drying the reaction liquid to obtain the perylene-3, 4,9, 10-tetracarboxylic dianhydride grafted molecular sieve;

s4, dissolving octadecanethiol in isopropanol, adding the perylene-3, 4,9, 10-tetracarboxylic dianhydride grafted molecular sieve obtained in the step S3, stirring uniformly, and adding the mixture into N²Heating to 90-95 ℃ in the atmosphere, fully reacting for 8-10 h, and reacting after the reaction liquid is cooled to room temperatureThe solution is sequentially centrifuged, washed and dried to obtain the perylene-3, 4,9, 10-tetracarboxylic dianhydride grafted molecular sieve modified by octadecanethiol;

s5, uniformly mixing the octadecanethiol-modified perylene-3, 4,9, 10-tetracarboxylic dianhydride grafted molecular sieve obtained in the step S4, ethoxylated bisphenol A diacrylate, a photoinitiator and a surface wetting agent according to a preset mass ratio, uniformly coating the mixture on a glass substrate, and obtaining a volatile organic compound detection film after ultraviolet irradiation;

s6, placing the volatile organic compound detection films obtained in the step S5 in volatile organic compound standard steam to be detected with different concentrations, performing fluorescence detection on the volatile organic compound detection films, and drawing a standard curve of fluorescence intensity changing along with the concentration of the volatile organic compound steam; and then placing the volatile organic compound detection film in steam to be detected, performing fluorescence detection, and calculating the concentration of the volatile organic compound to be detected in the steam to be detected according to the standard curve.

Further, in step S1, the hydrothermal reaction method for preparing the cerium-doped mesoporous molecular sieve comprises the following steps: mixing ethyl orthosilicate and deionized water, stirring at 35 ℃ for 40min, sequentially adding sodium hydroxide, sodium fluoride and cerium nitrate, and fully stirring for 60min to obtain a mixed solution; adding hexadecyl trimethyl ammonium bromide into the mixed solution, stirring for 60min, placing the reaction solution into a high-pressure kettle, heating at 120 ℃ for 24h, and sequentially filtering, washing, drying and roasting the product to obtain a cerium-doped mesoporous molecular sieve; the roasting treatment temperature is 550 ℃, and the roasting time is 4 hours.

Furthermore, in the step of preparing the cerium-doped mesoporous molecular sieve by the hydrothermal reaction method, the molar ratio of the ethyl orthosilicate, the deionized water, the sodium hydroxide, the sodium fluoride, the cerium nitrate and the hexadecyl trimethyl ammonium bromide is 1:62:0.5:0.1 (0.005-0.04): 0.65.

Further, in step S2, the mass ratio of the cerium-doped mesoporous molecular sieve to 3-aminopropyltrimethoxysilane is 2: 1.

Further, in step S3, the preset mass ratio of the perylene-3, 4,9, 10-tetracarboxylic dianhydride to the aminopropyl-modified cerium-doped mesoporous molecular sieve is (2-4): 5.

Further, in step S4, the mass ratio of the octadecanethiol to the perylene-3, 4,9, 10-tetracarboxylic dianhydride grafted molecular sieve is 3: 2.

Further, in step S5, the preset mass ratio of the octadecanethiol-modified perylene-3, 4,9, 10-tetracarboxylic dianhydride grafted molecular sieve to the ethoxylated bisphenol a diacrylate, the photoinitiator and the surface wetting agent is 92.5:5:2: 0.5.

Further, in step S5, the photoinitiator is 2,4, 6-trimethylbenzoyl-diphenylphosphine oxide, and the surfactant is polyether-modified polydimethylsiloxane.

Further, in step S5, the thickness of the VOC detection film is 8-12 μm.

Further, in step S6, the volatile organic compound to be tested includes, but is not limited to, one of methanol, formaldehyde, dimethylformamide, or tetrahydrofuran.

Compared with the prior art, the invention has the beneficial effects that:

1. according to the invention, the cerium-doped mesoporous molecular sieve is prepared, and then the cerium-doped mesoporous molecular sieve is subjected to aminopropyl modification, perylene-3, 4,9, 10-tetracarboxylic dianhydride grafting and octadecanethiol modification in sequence, so that the detection membrane with excellent adsorption and desorption properties and high sensitivity to volatile organic compounds is prepared after encapsulation; by utilizing the fluorescence intensity difference of the detection membrane to volatile organic compounds with different concentrations, the invention establishes a standard curve between the concentration of the volatile organic compounds and the fluorescence intensity of the detection membrane, and can accurately and sensitively quantitatively detect the concentration of the volatile organic compounds, thereby realizing the high-precision detection of the volatile organic compounds.

2. According to the invention, through preparing the cerium-doped mesoporous molecular sieve and using the cerium-doped mesoporous molecular sieve as the volatile organic compound detection membrane, the volatile organic compound can be adsorbed and desorbed by utilizing rich pore channel structures in the molecular sieve, so that the volatile organic compound is effectively enriched in the detection process, the detection sensitivity is improved, the volatile organic compound is desorbed after the detection is finished, the cyclic use of the detection membrane is realized, and the detection cost is reduced. Meanwhile, in the process of preparing the molecular sieve, a proper amount of rare earth atom cerium is introduced to replace part of silicon atoms, so that the hydrophobicity of the molecular sieve can be improved, and the organic affinity of the molecular sieve is improved; the cerium doping process can also properly increase the number of defects in the molecular sieve, so that the silicon hydroxyl defects existing on the surface and in the pore channel of the molecular sieve are used as anchor points, and the subsequent modification, grafting and effective modification processes are conveniently carried out. In addition, because defects caused in the cerium doping process can have certain influence on the hydrothermal stability of the molecular sieve, fluorine ions are introduced in the preparation process of the molecular sieve, so that the stability of the molecular sieve is guaranteed, and the molecular sieve can meet the requirements of practical application.

3. According to the invention, 3-aminopropyltrimethoxysilane is introduced to carry out aminopropyl modification on the cerium-doped mesoporous molecular sieve, so that the dispersibility of the molecular sieve can be improved, the agglomeration phenomenon of the molecular sieve is reduced, and the process of carrying out adsorption and desorption performance on volatile organic compounds is improved; can also provide more anchor points for the molecular sieve, and is convenient for grafting the perylene-3, 4,9, 10-tetracarboxylic dianhydride on the molecular sieve. Perylene-3, 4,9, 10-tetracarboxylic dianhydride is used as a fluorescent dye with high quantum yield, and is grafted on a molecular sieve, so that the quantitative detection of volatile organic compounds can be realized by utilizing the fluorescence difference of the perylene-3, 4,9, 10-tetracarboxylic dianhydride to volatile organic compounds with different concentrations, and the molecular sieve can be used for protecting, supporting and resisting corrosion, so that the stability of the perylene-3, 4,9, 10-tetracarboxylic dianhydride is improved, and the detection membrane has high sensitivity and stability. In addition, the perylene-3, 4,9, 10-tetracarboxylic dianhydride grafted molecular sieve is modified by introducing octadecanethiol, so that the hydrophobicity of the obtained detection membrane can be further improved, the detection membrane has excellent organic affinity, and the sensitivity of the detection membrane to volatile organic compounds is further improved.

4. The detection method for detecting the volatile organic compound with high precision, provided by the invention, is simple and easy to implement, the detection membrane can be repeatedly used after the preparation is finished, the overall detection process is low in cost, high in sensitivity and good in accuracy, the high-precision detection of the volatile organic compound is realized, and the requirements of practical application can be met.

Drawings

FIG. 1 is a graph showing fluorescence spectra of detection films prepared in example 1 of the present invention in each vapor having different methanol concentrations;

FIG. 2 is a standard curve of the peak fluorescence intensity of the detection membrane according to the change of the methanol concentration in example 1 of the present invention;

FIG. 3 is a fluorescence spectrum before and after the purification of the detection membrane in example 1 of the present invention;

FIG. 4 is a graph showing the variation of peak fluorescence intensity of each detection membrane with the molar ratio of tetraethoxysilane to cerium nitrate;

FIG. 5 is a graph showing the variation of the peak fluorescence intensity of each detection film with the amount of perylene-3, 4,9, 10-tetracarboxylic dianhydride added;

FIG. 6 is a graph of fluorescence peak intensities for different VOCs.

Detailed Description

The following detailed description of the preferred embodiments of the present invention, taken in conjunction with the accompanying drawings, will make the advantages and features of the invention easier to understand by those skilled in the art, and thus will clearly and clearly define the scope of the invention. It is to be understood that the described embodiments are merely a few embodiments of the invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments of the present invention without any inventive step, are within the scope of the present invention.

The invention provides a detection method for detecting volatile organic compounds with high precision, which comprises the following steps:

s1, preparing a cerium-doped mesoporous molecular sieve by a hydrothermal reaction method;

s2, uniformly dispersing the cerium-doped mesoporous molecular sieve obtained in the step S1 in isopropanol, adding a predetermined amount of 3-aminopropyltrimethoxysilane, fully reacting for 8-10 hours at 85-95 ℃, and after the reaction liquid is cooled to room temperature, sequentially centrifuging, washing and drying the reaction liquid to obtain an aminopropyl modified cerium-doped mesoporous molecular sieve;

s3, mixing perylene-3, 4,9, 10-tetracarboxylic dianhydride with the aminopropyl modified cerium-doped mesoporous molecular sieve obtained in the step S2 according to a preset mass ratio, uniformly dispersing the mixture in isopropanol, fully reacting at room temperature for 10-12 hours, and then sequentially centrifuging, washing and drying the reaction liquid to obtain the perylene-3, 4,9, 10-tetracarboxylic dianhydride grafted molecular sieve;

s4, dissolving octadecanethiol in isopropanol, adding the perylene-3, 4,9, 10-tetracarboxylic dianhydride grafted molecular sieve obtained in the step S3, stirring uniformly, and adding the mixture into N²Heating to 90-95 ℃ in the atmosphere, fully reacting for 8-10 h, cooling the reaction liquid to room temperature, and then sequentially centrifuging, washing and drying the reaction liquid to obtain the perylene-3, 4,9, 10-tetracarboxylic dianhydride grafted molecular sieve modified by octadecanethiol;

s5, uniformly mixing the octadecanethiol-modified perylene-3, 4,9, 10-tetracarboxylic dianhydride grafted molecular sieve obtained in the step S4, ethoxylated bisphenol A diacrylate, a photoinitiator and a surface wetting agent according to a preset mass ratio, uniformly coating the mixture on a glass substrate, and obtaining a volatile organic compound detection film after ultraviolet irradiation;

s6, placing the volatile organic compound detection films obtained in the step S5 in volatile organic compound standard steam to be detected with different concentrations, performing fluorescence detection on the volatile organic compound detection films, and drawing a standard curve of fluorescence intensity changing along with the concentration of the volatile organic compound steam; and then placing the volatile organic compound detection film in steam to be detected, performing fluorescence detection, and calculating the concentration of the volatile organic compound to be detected in the steam to be detected according to the standard curve.

In step S1, the hydrothermal reaction method for preparing the cerium-doped mesoporous molecular sieve comprises the following steps: mixing ethyl orthosilicate and deionized water, stirring at 35 ℃ for 40min, sequentially adding sodium hydroxide, sodium fluoride and cerium nitrate, and fully stirring for 60min to obtain a mixed solution; adding hexadecyl trimethyl ammonium bromide into the mixed solution, stirring for 60min, placing the reaction solution into a high-pressure kettle, heating at 120 ℃ for 24h, and sequentially filtering, washing, drying and roasting the product to obtain a cerium-doped mesoporous molecular sieve; the roasting treatment temperature is 550 ℃, and the roasting time is 4 hours.

In the step of preparing the cerium-doped mesoporous molecular sieve by the hydrothermal reaction method, the molar ratio of the ethyl orthosilicate to the deionized water to the sodium hydroxide to the sodium fluoride to the cerium nitrate to the hexadecyl trimethyl ammonium bromide is 1:62:0.5:0.1 (0.005-0.04) to 0.65.

In step S2, the mass ratio of the cerium-doped mesoporous molecular sieve to 3-aminopropyltrimethoxysilane is 2: 1.

In step S3, the preset mass ratio of the perylene-3, 4,9, 10-tetracarboxylic dianhydride to the aminopropyl-modified cerium-doped mesoporous molecular sieve is (2-4): 5.

In step S4, the mass ratio of the octadecanethiol to the perylene-3, 4,9, 10-tetracarboxylic dianhydride grafted molecular sieve is 3: 2.

In step S5, the predetermined mass ratio of the octadecanethiol-modified perylene-3, 4,9, 10-tetracarboxylic dianhydride grafted molecular sieve to the ethoxylated bisphenol a diacrylate, the photoinitiator, and the surface wetting agent is 92.5:5:2: 0.5.

In step S5, the photoinitiator is 2,4, 6-trimethylbenzoyl-diphenylphosphine oxide, and the surfactant is polyether-modified polydimethylsiloxane.

In step S5, the thickness of the VOC detection film is 8-12 μm.

In step S6, the volatile organic compound to be tested includes, but is not limited to, one of methanol, formaldehyde, dimethylformamide, or tetrahydrofuran.

The following describes a detection method for detecting volatile organic compounds with high accuracy, which is provided by the present invention, with reference to examples and drawings.