CN118725573A - A dissolved oxygen fluorescent chemical sensing material and its preparation and application - Google Patents

Abstract

The invention relates to a dissolved oxygen fluorescent chemical sensing material and its preparation and application, wherein the components include tris(4,7-biphenyl-1,10-phenanthroline)dichlororuthenium(II), alcohol and polydimethylsiloxane (PDMS). The dissolved oxygen fluorescent sensing film obtained by the invention has good uniformity, good sensing performance and good stability.

Description

A dissolved oxygen fluorescent chemical sensing material and its preparation and application

Technical Field

The invention belongs to the field of sensing, and particularly relates to a dissolved oxygen fluorescent chemical sensing material and a preparation method and application thereof.

Background Art

As the external environment changes, the chemical or physical properties of the substance change, which causes the fluorescence signal to change under the same excitation light. Compared with traditional detection methods, fluorescent chemical sensors have the advantages of visualization, high sensitivity, fast detection speed, and simple and easy operation. At present, they have been widely used in environmental, biological, and medical detection fields.

Dissolved oxygen refers to oxygen dissolved in water. The dissolved oxygen content in general agricultural water is above 2 mg/L, and in clear rivers and lakes it is 6-8 mg/L. Detecting dissolved oxygen in water can ensure the normal operation of fishery breeding and product production, and can also reflect some environmental pollution events, such as "red tide". Therefore, dissolved oxygen detection is of great significance.

Tris(4,7-biphenyl-1,10-phenanthroline)dichlororuthenium(II) (Ru(dpp) ₃ Cl ₂ ) is a common oxygen-sensitive substance that emits orange fluorescence under 450nm excitation light with an emission peak at 610nm. In addition, its fluorescence intensity decreases significantly with the increase of oxygen content, so it is often used to detect oxygen content. Polydimethylsiloxane (PDMS) is an inexpensive elastomer with good biocompatibility, stability and high transparency (≥90%). However, the current single PDMS system has poor air permeability, and Ru(dpp) ₃ Cl ₂ cannot be evenly dispersed in the PDMS system, making it impossible to detect the dissolved oxygen content in water.

Summary of the invention

In view of the defects of the prior art, the technical problem to be solved by the present invention is to provide a dissolved oxygen fluorescent chemical sensing material and its preparation and application. The present invention solves the current problem of poor dispersibility and poor sensing performance of Ru(dpp) ₃ Cl ₂ in polydimethylsiloxane (PDMS).

The present invention provides a sensing material, which comprises the following components by weight:

Preferably, the alcohol is one or more of ethanol and silanol; the silanol is one or more of trimethylsilanol, triethylsilanol, tert-butyldimethylsilanol, triisopropylsilanol, dimethyl(thiophen-2-yl)silanol, diethyl(isopropyl)silanol, and diphenylsilanol.

More preferably, the silanol is triethylsilanol and tert-butyldimethylsilanol in a mass ratio of 1:10 to 10:1.

Preferably, the crosslinking agent is a fluorine-containing substance; the fluorine-containing substance is one or more of (3,3,3-trifluoropropyl)trimethoxysilane, di-tert-butyldifluorosilane, 3-aminopropyldimethylfluorosilane, 3,3,3-trifluoropropyltriethoxysilane, triethylfluorosilane, and tridecafluorooctyltriethoxysilane.

Preferably, the polydimethylsiloxane PDMS comprises a prepolymer A and a crosslinking agent B; the catalyst is one or more of formic acid, acetic acid, hydrochloric acid, sulfuric acid, nitric acid, sodium hydroxide, potassium hydroxide, and ammonia water.

Furthermore, the mass ratio of the prepolymer A to the crosslinking agent B is 1:1.

By weight, the components include:

The present invention provides a method for preparing any of the above-mentioned sensing materials, comprising:

Polydimethylsiloxane PDMS, tri(4,7-biphenyl-1,10-phenanthroline) dichlororuthenium (II), alcohol, a crosslinking agent and a catalyst are mixed, stirred, ultrasonicated, degassed and cured.

The preparation method comprises: mixing tri(4,7-biphenyl-1,10-phenanthroline)ruthenium(II) dichloride and alcohol to obtain fluorescent liquid, then mixing with polydimethylsiloxane (PDMS), a crosslinking agent and a catalyst, stirring, ultrasonicating, degassing and curing.

The curing is carried out in a mold.

Preferably, the ultrasound is performed at room temperature for 0 to 60 minutes.

Preferably, the degassing is vacuum degassing at room temperature and -0.05Mpa to -0.1Mpa.

Preferably, the curing is performed at 60-120° C. for 6-48 hours.

The invention provides a dissolved oxygen fluorescent chemical sensing membrane, wherein the sensing membrane contains the sensing material.

The invention provides an application of the sensing material in dissolved oxygen determination.

The present invention provides a dissolved oxygen determination method, comprising: adding a liquid to be measured into a container (such as a membrane tool) equipped with a dissolved oxygen fluorescence sensor membrane, irradiating the dissolved oxygen fluorescence sensor with 450nm excitation light after 10-30min (preferably 30min), and determining the emission light intensity at 610nm, wherein the emission light intensity at 610nm is directly related to the dissolved oxygen concentration in the liquid, and wherein the emission light intensity and the dissolved oxygen concentration are negatively correlated.

Beneficial Effects

The present invention prepares a dissolved oxygen fluorescence chemical sensing membrane by mixing Ru(dpp) ₃ Cl ₂ and PDMS.

The method of the invention has the characteristics of simple operation, short curing time and mild reaction.

The dissolved oxygen fluorescent chemical sensing membrane of the present invention has the characteristics of good uniformity, excellent sensing performance and good stability.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1. SEM images of the surface of dissolved oxygen fluorescent chemical sensing membrane (a) Example 1, (b) Example 2, (c) Example 3, (d) Example 4, (e) Example 5;

Figure 2. EDS images of the surface of dissolved oxygen fluorescent chemical sensing membrane (a) Example 1, (b) Example 2, (c) Example 3, (d) Example 4, (e) Example 5;

Figure 3. Contact angle diagrams of dissolved oxygen fluorescent chemical sensing films (a) Example 1, (b) Example 2, (c) Example 3, (d) Example 4, (e) Example 5;

Figure 4. UV-vis spectrum of dissolved oxygen fluorescence chemical sensing membrane;

Figure 5. Fluorescence spectra of dissolved oxygen fluorescent chemical sensing membranes (a) Example 1, (b) Example 2, (c) Example 3, (d) Example 4, (e) Example 5;

FIG6 . Fluorescence spectra of Example 3 in an oxygen-free water environment on the day and the tenth day after curing.

Figure 7. (a) Fluorescence spectra of Example 3 at different dissolved oxygen contents (8.25, 5.89, 3.53 mg/L); (b) Linear relationship between fluorescence intensity at 610 nm and dissolved oxygen content.

DETAILED DESCRIPTION

The present invention will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and are not intended to limit the scope of the present invention. In addition, it should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms fall within the scope limited by the appended claims of the application equally.

Sources of main raw materials;

PDMS (A and B glue) is an optical grade liquid silica gel of model BESIL 8250A/B; tris(4,7-biphenyl-1,10-phenanthroline) dichloride ruthenium (II) was purchased from Adamas Company.

Related tests:

The transparency of the sensor was characterized by using a UV-visible near-infrared spectrometer (UV-vis) with a model of UV3600. The scanning mode was transmittance (%), integrating sphere test; the scanning range was 325-1100 nm.

Fluorescence Spectrum The fluorescence intensity of the sensor in the presence and absence of oxygen was detected using a fluorescence spectrometer (PL) of model QM/TM. The specific test parameters were excitation wavelength: λ=450nm, measurement range: 500-750nm, where oxygen-free water was 0.12g/mL sodium sulfite solution, and saturated dissolved oxygen water was deionized water that was exposed to oxygen in the air for 3 days at room temperature 25°C. Where I _{oxygen-free water} /I _{saturated dissolved oxygen water} is the ratio of the fluorescence intensity of the sensor membrane at 610nm in the oxygen-free water and saturated dissolved oxygen environments.

Contact Angle The water contact angle of the sensor was determined using an OCA40Micro contact angle meter (CA), and the single extrusion water volume was set to 3 μL.

SEM A scanning electron microscope (SEM) of model SU8010 was used to characterize the microscopic morphology of the sensor. The sample preparation process was as follows: double-sided conductive adhesive was attached to the sample stage, the sample was cut into a suitable size and attached to the conductive adhesive, and gold was sprayed before the experiment for 120 seconds. Energy dispersive X-ray spectroscopy (EDS) was also performed on SU8010 to characterize the element distribution of the sensor, and the test element was Ru.

Example 1

Select a clean glass bottle, add 1 part of each of the A and B components of the two-component PDMS, and stir evenly. Then mix 0.0005 parts of Ru(dpp) ₃ Cl ₂ with 0.25 parts of ethanol and add them to the bottle. You can see that the fluorescent liquid gathers on the surface of PDMS with obvious stratification. Use a glass rod to stir the mixture of the above substances evenly. You can see that the fluorescent liquid gradually dissolves, and the mixture as a whole presents a transparent red-orange solution state. Ultrasonicate it at an ultrasonic power of 150W and room temperature for 10 minutes. Then vacuum degassing at room temperature and -0.09Mpa, you can see a large number of bubbles emerging from the solution, and no bubbles appear in the solution after 2 to 3 minutes. Transfer the solution to the membrane and cure it in a blast oven at 80°C for 24 hours. After curing, a transparent and uniform dissolved oxygen fluorescent chemical sensing membrane with a light yellow color is obtained. From the SEM image (Figure 1a), it can be observed that the surface of the sensing membrane has obvious wrinkles and no obvious defects. The subsequent EDS image of the Ru element (Figure 2a) proves that the fluorescent substance (Ru(dpp) ₃ Cl ₂ ) is evenly dispersed in the PDMS matrix. The contact angle image (Figure 3a) shows that when ethanol is used, the sensing membrane is relatively hydrophilic as a whole, and its contact angle is 86.3°. The UV-vis spectrum (Figure 4) shows that the sensing membrane has a certain transparency (≥20%) under visible light. Figure 5a is the fluorescence spectrum of Example 1, and its fluorescence contrast in an anaerobic/aerobic environment is only 1.16.

Example 2

Select a clean glass bottle, add 1 part of each of the A and B components of the two-component PDMS, and stir evenly. Then mix 0.0005 parts of Ru(dpp) ₃ Cl ₂ and 0.25 parts of triethylsilanol and add them to the bottle. You can see that the fluorescent liquid gathers on the surface of PDMS with obvious stratification. Use a glass rod to stir the mixture of the above substances evenly. You can see that the fluorescent liquid gradually dissolves, and the mixture as a whole presents a transparent red-orange solution state. Ultrasonicate it at an ultrasonic power of 150W and room temperature for 10 minutes. Then vacuum degassing at room temperature and -0.09Mpa, you can see a large number of bubbles emerging from the solution, and no bubbles appear in the solution after 2 to 3 minutes. Transfer the solution to the membrane and cure it in a blast oven at 80°C for 24 hours. After curing, a transparent and uniform dissolved oxygen fluorescent chemical sensing membrane with a light yellow color is obtained. From the SEM image (Fig. 1b), it can be observed that the surface of the sensing membrane has obvious wrinkles and no obvious defects. The subsequent EDS image of the Ru element (Fig. 2b) proves that the fluorescent substance (Ru(dpp) ₃ Cl ₂ ) is evenly dispersed in the PDMS matrix. The contact angle image (Fig. 3b) shows that the sensing membrane has obvious hydrophobicity, and its contact angle is 101.2°. The UV-vis spectrum (Fig. 4) shows that the sensing membrane has good transparency under visible light, and the transmittance above 550nm can reach more than 90%. Fig. 5b is the fluorescence spectrum of Example 2, and its fluorescence contrast in anaerobic/aerobic environment reaches 3.43.

Example 3

Select a clean glass bottle, add 1 part of each of the A and B components of the two-component PDMS, and stir evenly. Then mix 0.00055 parts of Ru(dpp) ₃ Cl ₂ with 0.25 parts of tert-butyldimethylsilanol and 0.025 parts of triethylsilanol and add them to the bottle. You can see that the fluorescent liquid gathers on the surface of PDMS with obvious stratification. Then add 0.083 parts of (3,3,3-trifluoropropyl)trimethoxysilane to the glass bottle, and then add 0.42 parts of acetic acid. Use a glass rod to stir the mixture of the above substances evenly. You can see that the fluorescent liquid gradually dissolves, and the mixture as a whole presents a transparent light reddish orange solution state. Ultrasonicate it at an ultrasonic power of 150W and room temperature for 10 minutes. Then vacuum degassing at room temperature and -0.09Mpa, you can see a large number of bubbles coming out of the solution, and no bubbles appear in the solution after 2 to 3 minutes. Transfer the solution to the membrane mold and control the humidity in the blast oven between 45 and 85%. The membrane was placed in a blast oven and cured at 80°C for 24 hours. After the curing was completed, a transparent and uniform dissolved oxygen fluorescent chemical sensing membrane with a light yellow color was obtained. From the SEM image (Figure 1c), it can be observed that the surface of the sensing membrane has obvious wrinkles and no obvious defects. The EDS image of the Ru element (Figure 2c) then proved that the fluorescent substance (Ru(dpp) ₃ Cl ₂ ) was evenly dispersed in the PDMS matrix. The contact angle image (Figure 3c) shows that the sensing membrane has obvious hydrophobicity, and its contact angle is 110.8°. The UV-vis spectrum (Figure 4) shows that the sensing membrane has good transparency under visible light, and the transmittance above 550nm can reach more than 90%. Figure 5c is the fluorescence spectrum of Example 3, and its fluorescence contrast in an anaerobic/aerobic environment is 5.18. The stability of the dissolved oxygen sensing membrane was then characterized. It can be seen from Figure 6 that the fluorescence intensity of the sensing membrane in an anaerobic environment hardly changes 10 days after preparation, proving that it has good stability. FIG7 shows the fluorescence spectra of Example 3 at different dissolved oxygen contents and the linear relationship between the fluorescence intensity at 610 nm and the dissolved oxygen content. The results show that the dissolved oxygen content and the fluorescence intensity present an approximately linear relationship, and the linear equation is Y=76795-5872x, R ² =0.968.

Example 4

Select a clean glass bottle, add 1 part of each of the A and B components of the two-component PDMS, and stir evenly. Then mix 0.0005 parts of Ru(dpp) ₃ Cl ₂ and 0.25 parts of tert-butyldimethylsilanol and add them to the bottle. You can see that the fluorescent liquid gathers on the surface of PDMS with obvious stratification. Use a glass rod to stir the mixture of the above substances evenly. You can see that the fluorescent liquid gradually dissolves, and the mixture as a whole presents a transparent light reddish orange solution state. Ultrasonicate it at an ultrasonic power of 150W and room temperature for 10 minutes. Then vacuum degassing at room temperature and -0.09Mpa, you can see a large number of bubbles emerging from the solution, and no bubbles appear in the solution after 2 to 3 minutes. Transfer the solution to the membrane mold and control the humidity in the blast oven between 45 and 85%. Put the membrane mold in a blast oven and cure it at 80°C for 24 hours. After the curing is completed, a transparent and uniform dissolved oxygen fluorescent chemical sensing membrane with a light yellow color is obtained. From the SEM image (Figure 1d), it can be observed that the surface of the sensing membrane has obvious wrinkles and no obvious defects. The subsequent EDS image of the Ru element (Figure 2d) proves that the fluorescent substance (Ru(dpp) ₃ Cl ₂ ) is evenly dispersed in the PDMS matrix. The contact angle image (Figure 3d) shows that the sensing membrane has obvious hydrophobicity, and its contact angle is 118.5°. The UV-vis spectrum (Figure 4) shows that the sensing membrane has good transparency under visible light, and the transmittance above 550nm can reach more than 90%. Figure 5d is the fluorescence spectrum of Example 4, and its fluorescence contrast in an anaerobic/aerobic environment reaches 1.63.

Example 5

Select a clean glass bottle, add 1 part of each of the A and B components of the two-component PDMS, and stir evenly. Then mix 0.0005 parts of Ru(dpp) ₃ Cl ₂ and 0.25 parts of triethylsilanol and add them to the bottle. You can see that the fluorescent liquid gathers on the surface of PDMS with obvious stratification. Then add 0.083 parts of (3,3,3-trifluoropropyl)trimethoxysilane to the glass bottle, and then add 0.42 parts of acetic acid. Use a glass rod to stir the mixture of the above substances evenly. You can see that the fluorescent liquid gradually dissolves, and the mixture as a whole presents a transparent light reddish orange solution state. Ultrasonicate it at an ultrasonic power of 150W and room temperature for 10 minutes. Then vacuum degassing at room temperature and -0.09Mpa, you can see a large number of bubbles coming out of the solution, and no bubbles appear in the solution after 2 to 3 minutes. Transfer the solution to the film mold and control the humidity in the blast oven between 45 and 85%. Put the film mold in a blast oven and cure it at 80℃ for 24 hours. After curing, a transparent and uniform dissolved oxygen fluorescent chemical sensing membrane with a light yellow color was obtained. From the SEM image (Figure 1e), it can be observed that the surface of the sensing membrane has obvious wrinkles and no obvious defects. The subsequent EDS image of the Ru element (Figure 2e) proves that the fluorescent substance (Ru(dpp) ₃ Cl ₂ ) is evenly dispersed in the PDMS matrix. The contact angle image (Figure 3e) shows that the sensing membrane has obvious hydrophobicity, and its contact angle is 118.9°. The UV-vis spectrum (Figure 4) shows that the sensing membrane has good transparency under visible light, and the transmittance above 550nm can reach more than 90%. Figure 5e is the fluorescence spectrum of Example 5, and its fluorescence contrast ratio in an anaerobic/aerobic environment reaches 2.61.

Table 1 Comparison of fluorescence intensity at 610 nm of different embodiments (I _{oxygen-free water} /I _{saturated dissolved oxygen water} )

Example 1 Example 2 Example 3 Example 4 Example 5 I _{oxygen-free water} /I _{saturated dissolved oxygen water} 1.16 3.43 5.18 1.63 2.61

Claims (10)

1. A sensing material, characterized in that, by weight, the components include: 2. The sensing material according to claim 1 is characterized in that the alcohol is one or more of ethanol and silanol; the silanol is one or more of trimethylsilanol, triethylsilanol, tert-butyldimethylsilanol, triisopropylsilanol, dimethyl(thiophene-2-yl)silanol, diethyl(isopropyl)silanol, and diphenylsilanol. 3. The sensing material according to claim 1 is characterized in that the cross-linking agent is a fluorine-containing substance; the fluorine-containing substance is one or more of (3,3,3-trifluoropropyl)trimethoxysilane, di-tert-butyldifluorosilane, 3-aminopropyldimethylfluorosilane, 3,3,3-trifluoropropyltriethoxysilane, triethylfluorosilane, and tridecafluorooctyltriethoxysilane. 4. The sensing material according to claim 1 is characterized in that the polydimethylsiloxane (PDMS) comprises a prepolymer A and a crosslinking agent B; and the catalyst is one or more of formic acid, acetic acid, hydrochloric acid, sulfuric acid, nitric acid, sodium hydroxide, potassium hydroxide, and ammonia water. 5. The sensing material according to claim 1, characterized in that, in parts by weight, the components include: 6. A method for preparing the sensing material according to any one of claims 1 to 5, comprising: Polydimethylsiloxane PDMS, tri(4,7-biphenyl-1,10-phenanthroline) dichlororuthenium (II), alcohol, a crosslinking agent and a catalyst are mixed, stirred, ultrasonicated, degassed and cured. 7. The preparation method according to claim 6, characterized in that the ultrasound is performed at room temperature for 0 to 60 minutes; the degassing is performed at room temperature and vacuum degassing at -0.05Mpa to -0.1Mpa; The curing is carried out at 60 to 120° C. for 6 to 48 hours. 8. A dissolved oxygen fluorescent chemical sensor membrane, characterized in that the sensor membrane contains the sensing material according to claim 1. 9. Use of the sensing material according to claim 1 in dissolved oxygen determination. 10. A method for determining dissolved oxygen, comprising: adding a liquid to be measured into a container containing a dissolved oxygen fluorescence sensor membrane, irradiating the dissolved oxygen fluorescence sensor with 450nm excitation light after 10-30 minutes, and determining the emission light intensity at 610nm, wherein the emission light intensity at 610nm is directly related to the dissolved oxygen concentration in the liquid.