Fluorescent cap for measuring dissolved oxygen, preparation method and detection device

Abstract

The invention discloses a fluorescent cap for measuring dissolved oxygen, a preparation method and a detection device.The fluorescent cap comprises a lens, a fluorescent layer, a reflecting layer and a shading layer, and one side face of the lens is sequentially covered with the fluorescent layer, the reflecting layer and the shading layer. The fluorescent layer is formed by dispersing and curing raw materials including pentafluorophenyl vinyl silicone oil, pentafluorophenyl hydrogen-containing silicone oil, a platinum catalyst, an inhibitor and platinum (II) m-tetra (pentafluorophenyl) porphyrin; when the fluorescent cap is used for measuring the dissolved oxygen content in water with low oxygen content, the sensitivity is high, and the dissolved oxygen content measuring accuracy can be improved.

Description

Technical Field

[0001] The present application relates to the technical field of dissolved oxygen concentration detection, and in particular to a fluorescent cap for measuring dissolved oxygen, a preparation method and a detection device. Background Art

[0002] The fluorescence dissolved oxygen meter uses the fluorescence principle to stimulate the fluorescent substance in the sample to generate a fluorescent signal, and then determines the dissolved oxygen content in the water based on the fluorescent signal. It is fast, accurate, and convenient, and is one of the most widely used instruments in water quality testing.

[0003] Anaerobic reactors are used in the anaerobic treatment process of wastewater, and the oxygen concentration in the anaerobic reactor is a key factor affecting the activity and treatment efficiency of anaerobic microorganisms. When the dissolved oxygen level is too high, the anaerobic respiration of anaerobic microorganisms is inhibited and the treatment efficiency decreases; and too high a concentration of dissolved oxygen will also promote the growth of aerobic microorganisms, thereby destroying the stability of the anaerobic environment. In addition, the reproduction of aerobic microorganisms consumes a large amount of oxygen and organic matter, resulting in an imbalance in the environment during the anaerobic reaction period, affecting the metabolic activity and treatment effect of anaerobic microorganisms. Although anaerobic reactors need to maintain a low oxygen environment, too low a dissolved oxygen content level may also affect the activity of anaerobic microorganisms. Too low a dissolved oxygen level may limit the metabolic activity of some anaerobic microorganisms, the anaerobic process may become slow, the treatment efficiency may decrease, and the decomposition of organic matter may be incomplete or the accumulation of intermediate products may occur. Generally, the ideal concentration range of dissolved oxygen in anaerobic reactors is 0.1-0.5 mg / L. Within this range, anaerobic microorganisms can normally perform anaerobic respiration, decompose organic matter and generate energy.

[0004] In order to ensure the normal activity of anaerobic microorganisms during the anaerobic treatment of wastewater, dissolved oxygen meters are often used to monitor and control the dissolved oxygen content in the water body to ensure the biological treatment effect and effluent water quality. However, the current sensor for measuring dissolved oxygen content in water has a measurement accuracy of only 0.3 mg / L when the oxygen concentration is in the range of 0 to 20 mg / L, which cannot accurately reflect the dissolved oxygen concentration in the water, and to a certain extent affects the treatment effect of anaerobic reactors and other biochemical reactors. Summary of the invention

[0005] In view of the above-mentioned deficiencies in the prior art, the purpose of the present application is to provide a fluorescent cap, a preparation method and a detection device for measuring dissolved oxygen, aiming to improve the detection accuracy of low-concentration dissolved oxygen.

[0006] In order to achieve the above objectives, this application adopts the following technical solutions:

[0007] On the one hand, the present application discloses a fluorescent cap for measuring dissolved oxygen, comprising: a lens, and a fluorescent layer, a reflective layer and a light-shielding layer sequentially covering one side of the lens; wherein the fluorescent layer is formed by dispersing and solidifying raw materials including pentafluorophenyl vinyl silicone oil, pentafluorophenyl hydrogen-containing silicone oil, a platinum catalyst, an inhibitor and platinum (II) meta-tetrakis (pentafluorophenyl) porphyrin.

[0008] In some embodiments of the present application, the thicknesses of the fluorescent layer, the reflective layer and the light shielding layer are 5 to 50 μm respectively.

[0009] In some embodiments of the present application, the pentafluorophenyl vinyl silicone oil is prepared by hydrolysis and condensation of dimethoxybis(pentafluorophenyl)silane, dimethyldiethoxysilane, and methylvinyldiethoxysilane.

[0010] In some embodiments of the present application, the pentafluorophenyl hydrogenated silicone oil is prepared by hydrolysis and condensation of dimethoxybis(pentafluorophenyl)silane, dimethyldiethoxysilane and methyldiethoxysilane.

[0011] In some embodiments of the present application, the molar ratio of pentafluorophenyl, silicon and vinyl in the pentafluorophenyl vinyl silicone oil is 0.05-0.2:1:0.001-0.005; and / or the molar ratio of pentafluorophenyl, silicon and silicon hydrogen in the pentafluorophenyl hydrogen-containing silicone oil is 0.05-0.2:1:0.001-0.005.

[0012] In some embodiments of the present application, the reflective layer is formed by dispersing and curing raw materials including pentafluorophenyl vinyl silicone oil, pentafluorophenyl hydrogenated silicone oil, a platinum catalyst, an inhibitor and titanium dioxide.

[0013] The light shielding layer is formed by dispersing and curing raw materials including pentafluorophenyl vinyl silicone oil, pentafluorophenyl hydrogen-containing silicone oil, a platinum catalyst, an inhibitor and carbon black.

[0014] In some embodiments of the present application, the content of the titanium dioxide is 10% to 20% of the total amount of pentafluorophenyl vinyl silicone oil and pentafluorophenyl hydrogenated silicone oil in the reflective layer; the content of the carbon black is 5% to 10% of the total amount of pentafluorophenyl vinyl silicone oil and pentafluorophenyl hydrogenated silicone oil in the shading layer.

[0015] In some embodiments of the present application, the mass ratio of pentafluorophenyl vinyl silicone oil to pentafluorophenyl hydrogenated silicone oil in the composition for preparing the fluorescent layer, the reflective layer and the light shielding layer is 1:1.

[0016] On the other hand, the present application further discloses a method for preparing a fluorescent cap, wherein the fluorescent cap is the fluorescent cap as described in any one of the above items, and the preparation method comprises:

[0017] Prepare fluorescent glue forming the fluorescent layer, white pentafluorophenyl silicone oil forming the reflective layer, and black pentafluorophenyl silicone oil forming the light-shielding layer respectively;

[0018] Take a lens, apply the fluorescent glue to one side of the lens, and bake it to form the fluorescent layer;

[0019] Applying the white pentafluorophenyl silicone oil onto the fluorescent layer and baking to form the reflective layer;

[0020] The black pentafluorophenyl silicone oil is coated on the reflective layer and baked to solidify the fluorescent glue, the white pentafluorophenyl silicone oil and the black pentafluorophenyl silicone oil to obtain the fluorescent cap.

[0021] On the other hand, the present application further discloses a detection device for measuring dissolved oxygen, wherein the detection device comprises the fluorescent cap as described in any one of the above items.

[0022] Beneficial effects:

[0023] The fluorescent cap provided by the present application sequentially covers a fluorescent layer, a reflecting layer and a light-shielding layer on one side of the lens, and the fluorescent layer is formed by dispersing and curing raw materials including pentafluorophenyl vinyl silicone oil, pentafluorophenyl hydrogenated silicone oil, a platinum catalyst, an inhibitor and platinum (II) meta-tetrakis (pentafluorobenzene) porphyrin. The raw materials of the fluorescent layer are pentafluorophenyl vinyl silicone oil and pentafluorophenyl hydrogenated silicone oil, so that the cured fluorescent layer has greater flexibility, a larger gap between molecules, and a large solubility in oxygen, so it still has a high sensitivity to samples with a low oxygen concentration. In addition, platinum (II) meta-tetrakis (pentafluorobenzene) porphyrin has a high fluorescence intensity as a fluorescent indicator, so that it has a high sensitivity to dissolved oxygen and can quickly and accurately detect the concentration of dissolved oxygen. Both pentafluorophenyl vinyl silicone oil and pentafluorophenyl hydrogenated silicone oil contain pentafluorophenyl, and have a high solubility in platinum (II) meta-tetrakis (pentafluorobenzene) porphyrin, which can further improve the detection sensitivity of the fluorescent cap to dissolved oxygen.

[0024] Another aspect of the present application provides a method for preparing a fluorescent cap. The fluorescent cap prepared by the preparation method has a large solubility in oxygen and can improve the detection sensitivity of low oxygen concentration sample detection.

[0025] On the other hand, the detection device provided in the present application includes the above-mentioned fluorescent cap, which has high sensitivity when measuring dissolved oxygen in low-concentration water, and its detection limit can be as low as 0.01 mg / L with high accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 A schematic diagram of the structure of a fluorescent cap provided in one embodiment of the present application.

[0027] Explanation of the main component symbols: 1-lens; 2-fluorescent layer; 3-reflective layer; 4-light-shielding layer. DETAILED DESCRIPTION

[0028] The present application provides a fluorescent cap, a detection method and a detection device for determining dissolved oxygen in water. In order to make the purpose, technical solution and effect of the present application clearer and more specific, the present application is further described in detail with reference to the accompanying drawings and examples. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0029] In the description of the present application, it should be understood that the terms "upper", "lower", "left", "right", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, and a specific orientation structure and operation, and therefore, cannot be understood as a limitation on the present application. In addition, "first" and "second" are only for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present application, unless otherwise specified, "multiple" means two or more.

[0030] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, an electrical connection, or mutual communication; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0031] The present application provides a detection device for measuring dissolved oxygen in water. The detection device can be specifically a fluorescence dissolved oxygen analyzer, which can be used to measure the dissolved oxygen content in various water bodies, such as lakes, rivers, oceans, etc. In the present application, the detection device is mainly used for the detection of water bodies with low dissolved oxygen content.

[0032] The detection device includes a light source, a photodetector, a fluorescent cap, etc. The light source can be an LED light source. The LED light source is small in size, low in energy consumption, has a long service life, and the light intensity can be adjusted. The fluorescent cap is set in the light emission direction of the light source and is located at the test end of the photodetector. During the measurement process, the fluorescent cap is placed in the water sample, and the fluorescent substance is irradiated by the excitation light emitted by the light source. The fluorescent substance will emit a fluorescence signal of a certain intensity. When the oxygen molecules collide with the fluorescent molecules in the excited state, the oxygen molecules can absorb the energy of the excited state molecules and transfer the energy to the surrounding molecules through collisions between gas phase molecules. This process causes the originally excited state molecules to return to the ground state, and the fluorescence that should have been generated by radiation transition is weakened or disappears, thereby achieving fluorescence quenching. The concentration of dissolved oxygen in water can be determined by measuring the change in the fluorescence lifetime of the fluorescent substance.

[0033] See also Figure 1 The fluorescent cap includes a lens 1, and a fluorescent layer 2, a reflective layer 3 and a light-shielding layer 4 sequentially covering one side of the lens 1; wherein the fluorescent layer 2 is formed by dispersing and solidifying raw materials including pentafluorophenyl vinyl silicone oil, pentafluorophenyl hydrogen-containing silicone oil, a platinum catalyst, an inhibitor and platinum (II) meta-tetrakis (pentafluorophenyl) porphyrin.

[0034] Specifically, the fluorescent layer 2, the reflective layer 3 and the light shielding layer 4 are sequentially arranged on the light-emitting side of the lens 1. Pentafluorophenyl vinyl silicone oil and pentafluorophenyl hydrogen silicone oil have large gaps between molecules, good flexibility and high solubility in oxygen, so they still have high sensitivity to samples with low oxygen concentration.

[0035] As a fluorescent indicator, platinum (II)-tetrakis (pentafluorobenzene) porphyrin has high sensitivity to oxygen. After reacting specifically with oxygen, it can quickly change the fluorescence signal, achieve rapid response and detection of dissolved oxygen concentration, and can quickly and accurately detect the concentration of dissolved oxygen. In addition, platinum (II)-tetrakis (pentafluorobenzene) porphyrin has good chemical stability, is not easily affected by factors such as water quality and temperature, and can maintain stable fluorescence performance.

[0036] Both pentafluorophenyl vinyl silicone oil and pentafluorophenyl hydrogen silicone oil contain pentafluorophenyl groups, have good solubility for fluorescent indicators, and can further increase the concentration of the indicator in the fluorescent layer 2, thereby increasing the sensitivity of the fluorescent cap to dissolved oxygen.

[0037] In some embodiments of the present application, the thicknesses of the fluorescent layer 2, the reflective layer 3 and the light shielding layer 4 are 5 to 50 μm, respectively. The selection of these thicknesses can ensure that the fluorescence detector has the best performance. The thickness of the fluorescent layer 2 determines the emission efficiency and light intensity of the fluorescence. A thicker fluorescent layer can increase the intensity of the fluorescence signal, but too thick may cause self-absorption effect and reduce the signal-to-noise ratio. The thickness of the reflective layer 3 affects the reflection efficiency and directionality of the fluorescence. The appropriate thickness of the reflective layer can allow more fluorescence signals to be collected into the detector. The thickness of the light shielding layer 4 mainly plays the role of isolating external light interference, protecting the fluorescent signal from interference from external light, and improving the sensitivity of the detector. The fluorescent layer 2 of the above thickness allows the dissolved oxygen in the water to react quickly with the fluorescent indicator, and can also ensure that the fluorescent cap has sufficient detection accuracy. The reflective layer 3 of the above thickness can ensure the reflection effect of the light emitted by the light source. The light shielding layer 4 of the above thickness can ensure that it has a good light shielding effect.

[0038] In some embodiments of the present application, the reflective layer 3 is formed by dispersing and curing raw materials including pentafluorophenyl vinyl silicone oil, pentafluorophenyl hydrogenated silicone oil, platinum catalyst, inhibitor and white pigment. The same organosilicon compound is used in the materials of the reflective layer 3 and the fluorescent layer 2, which can improve the bonding force between the reflective layer 3 and the fluorescent layer 2 and ensure that the reflective layer 3 can stably cover the fluorescent layer 2.

[0039] Among the raw materials of the reflective layer 3, the white pigment can be one of titanium dioxide, lead white, zinc oxide, etc. Preferably, the white pigment is titanium dioxide. Titanium dioxide has excellent hiding power and color fastness, and has good water resistance. When used in the fluorescent cap, it can ensure the reflection effect of the emission layer on the excitation light.

[0040] In some embodiments of the present application, the content of white pigment is 10% to 20% of the total amount of pentafluorophenyl vinyl silicone oil and pentafluorophenyl hydrogen silicone oil in the reflective layer 3. The above content of white pigment can be evenly dispersed in the organic silicon compound in the reflective layer raw material, and the reflective layer 3 formed by curing has a good reflection effect on the excitation light.

[0041] In some embodiments of the present application, the light shielding layer 4 is formed by dispersing and curing raw materials including pentafluorophenyl vinyl silicone oil, pentafluorophenyl hydrogenated silicone oil, platinum catalyst, inhibitor and black pigment. The light shielding layer 4 and the reflective layer 3 use the same organic silicon compound in the material, which can improve the bonding force between the light shielding layer 4 and the reflective layer 3, and ensure that the light shielding layer 4 can stably cover the reflective layer 3.

[0042] In some embodiments of the present application, the black pigment can be one of carbon black, black iron oxide, etc. Preferably, the black pigment is carbon black, which has a small mass and excellent hiding power and color fastness, and has a good hiding effect on the excitation light. It is understandable that in other embodiments, other pigments with good hiding power and poor light transmission can also be used.

[0043] In some embodiments of the present application, the content of black pigment is 5% to 10% of the total amount of pentafluorophenyl vinyl silicone oil and pentafluorophenyl hydrogen silicone oil in the light-shielding layer 4. The above content of black pigment can be evenly dispersed in the organic silicon compound in the raw material of the light-shielding layer 4, and the light-shielding layer 4 formed by curing has an excellent light-shielding effect, preventing the excitation light from radiating outward and affecting the test effect.

[0044] In some embodiments of the present application, the mass ratio of pentafluorophenyl vinyl silicone oil to pentafluorophenyl hydrogen silicone oil in the composition for preparing the fluorescent layer 2, the reflective layer 3 and the light shielding layer 4 is 1:1. In the above ratio, the content of silicon hydrogen groups is slightly greater than the content of pentafluorophenyl groups. The pentafluorophenyl groups and silicon hydrogen groups in the fluorescent layer 2, the reflective layer 3 and the light shielding layer 4 are generally combined in a ratio of 1:1, but silicon hydrogen groups are easily decomposed. When preparing the composition, slightly increasing the proportion of silicon hydrogen groups will result in better curing effect.

[0045] In some embodiments of the present application, when preparing the composition before curing of the fluorescent layer 2, pentafluorophenyl vinyl silicone oil and pentafluorophenyl hydrogenated silicone oil are put into a reactor at a mass ratio of 1:1, and a platinum catalyst, an inhibitor and platinum (II) meta-tetrakis (pentafluorophenyl) porphyrin are added, mixed, ground and dispersed to obtain a fluorescent glue. Among them, the amount of platinum catalyst and inhibitor added is 0.01% to 0.08% of the amount of pentafluorophenyl silicone oil added. The amount of platinum (II) meta-tetrakis (pentafluorophenyl) porphyrin added is 0.1% to 0.5% of the amount of pentafluorophenyl silicone oil added. It is worth noting that the content of pentafluorophenyl silicone oil mentioned above and below refers to the total amount of pentafluorophenyl vinyl silicone oil and pentafluorophenyl hydrogenated silicone oil.

[0046] When preparing the composition before curing of the reflective layer 3, pentafluorophenyl vinyl silicone oil and pentafluorophenyl hydrogen silicone oil are put into a ball mill at a mass ratio of 1:1, and a platinum catalyst, an inhibitor and titanium dioxide are added, mixed, ground and dispersed to obtain white pentafluorophenyl silicone oil. The amount of the platinum catalyst and the inhibitor is 0.01% to 0.08% of the amount of the pentafluorophenyl silicone oil. The amount of the titanium dioxide is 10% to 20% of the amount of the pentafluorophenyl silicone oil.

[0047] When preparing the composition before curing of the light shielding layer 4, pentafluorophenyl vinyl silicone oil and pentafluorophenyl hydrogen silicone oil are put into a ball mill at a mass ratio of 1:1, and a platinum catalyst, an inhibitor and carbon black are added, mixed and ground and dispersed to obtain black pentafluorophenyl silicone oil. Among them, the addition amount of the platinum catalyst and the inhibitor is 0.01% to 0.08% of the addition amount of the pentafluorophenyl silicone oil. The addition amount of carbon black is 5% to 10% of the addition amount of the pentafluorophenyl silicone oil.

[0048] In some embodiments of the present application, the compositions of the fluorescent layer 2 , the reflective layer 3 and the light shielding layer 4 before curing are sequentially formed on the side of the lens 1 facing away from the light source by coating.

[0049] Specifically, the preparation method of the fluorescent cap includes the following steps:

[0050] Take a lens 1, apply the fluorescent glue on one side of the lens 1, and bake it in an oven at 80°C for 10 minutes;

[0051] White pentafluorophenyl silicone oil was coated on the fluorescent glue layer, and then baked in an oven at 80°C for 10 minutes;

[0052] Then, black pentafluorophenyl silicone oil is coated on the white pentafluorophenyl silicone oil layer, and then baked at 100-150°C for 3-5 hours to solidify the fluorescent glue, white pentafluorophenyl silicone oil and black pentafluorophenyl silicone oil to form a fluorescent layer 2, a reflective layer 3 and a light-shielding layer 4, respectively, to obtain a finished fluorescent cap.

[0053] In some embodiments of the present application, pentafluorophenyl vinyl silicone oil is prepared by hydrolysis and condensation of dimethoxybis(pentafluorophenyl)silane, dimethyldiethoxysilane, and methylvinyldiethoxysilane.

[0054] Specifically, the preparation method of pentafluorophenyl vinyl silicone oil comprises the following steps:

[0055] Weigh dimethyldiethoxysilane, dimethoxybis(pentafluorophenyl)silane, and methylvinyldiethoxysilane respectively according to the proportion;

[0056] Weighed dimethyldiethoxysilane, dimethoxybis(pentafluorophenyl)silane and methylvinyldiethoxysilane were placed in a reaction vessel, stirred, heated to 40°C, and hydrochloric acid solution was slowly added dropwise to the reaction vessel for about 40 minutes;

[0057] After the hydrochloric acid is added dropwise, continue stirring at about 83°C for 0.5h and boil under reflux;

[0058] Let the layers stand and separate the acid water. Wash the lower organic oil phase with deionized water until it becomes neutral.

[0059] Octamethylcyclotetrasiloxane and tetramethylammonium hydroxide in a mass ratio of 50:1 were added to a three-necked flask. Nitrogen was first passed through the system for a period of time, and then dehydrated under reduced pressure at 55°C and -0.098MPa for 1 hour. The temperature was then raised to 65°C for reduced pressure reaction. The reaction was carried out for about 3 to 4 hours to obtain a tetramethylammonium hydroxide siliconate catalyst with a mass fraction of about 2% of tetramethylammonium hydroxide.

[0060] The organic oil phase is azeotropically dehydrated at 115°C, and then stirred at 55°C for 0.5h; tetramethylammonium hydroxide silicon alkoxide catalyst is added to the organic phase, the catalyst accounts for 0.01% to 0.1% of the total feed amount, the temperature is raised to 100°C, the pressure is reduced to -0.09MPa, and the equilibrium reaction is carried out for 1 to 3h;

[0061] After the equilibration reaction is completed, the temperature is raised to 150°C for the decomposition reaction of tetramethylammonium hydroxide silicon alkoxide to "deactivate" the catalyst, and the temperature is kept for about 30 minutes, and then the temperature is raised to 200°C, and low molecular weight compounds are removed under a vacuum degree of -0.09MPa until no part flows out, and the distillation is stopped, cooled to room temperature, and the material is filtered to obtain high-viscosity pentafluorophenyl vinyl silicone oil.

[0062] Specifically, the molar ratio of pentafluorophenyl, silicon and vinyl in pentafluorophenyl vinyl silicone oil is 0.05-0.3:1:0.001-0.005. The above content of pentafluorophenyl makes pentafluorophenyl vinyl silicone oil have sufficient molecular gap, ensures that the generated silicone rubber has a large solubility in oxygen, and improves the sensitivity of the measurement. The above content of vinyl makes pentafluorophenyl vinyl silicone oil have high reactivity, can fully cross-link with pentafluorophenyl hydrogen silicone oil, and ensure the performance and service life of the product.

[0063] In some embodiments of the present application, the pentafluorophenyl hydrogenated silicone oil is prepared by hydrolysis and condensation of dimethoxybis(pentafluorophenyl)silane, dimethyldiethoxysilane and methyldiethoxysilane.

[0064] Specifically, the preparation method of pentafluorophenyl hydrogen-containing silicone oil comprises the following steps:

[0065] Dimethoxybis(pentafluorophenyl)silane, dimethyldiethoxysilane, methyldiethoxysilane, hydrochloric acid, deionized water and toluene were added to the reaction container respectively, stirred, and hydrolyzed at 60° C. for 5 h.

[0066] The organic layer was separated and added into a three-necked flask. 98% concentrated sulfuric acid was added under stirring. The mixture was reacted at 65° C. for 12 h. The mixture was then washed with distilled water until neutral. The solvent and small molecular compounds were removed by rotary evaporation to obtain pentafluorophenyl hydrogenated silicone oil.

[0067] Specifically, the molar ratio of pentafluorophenyl, silicon and silicon hydrogen in pentafluorophenyl hydrogen silicone oil is 0.05-0.3:1:0.001-0.005. The above content of pentafluorophenyl makes pentafluorophenyl hydrogen silicone oil have sufficient molecular gap, ensuring that the generated silicone rubber has a large solubility to dissolved oxygen, and improving the sensitivity of the measurement. The above content of hydrogen groups can ensure that the pentafluorophenyl hydrogen silicone oil has a large reactivity, can fully cross-link with pentafluorophenyl vinyl silicone oil, ensure that the silicone rubber product has a large molecular gap and flexibility, thereby ensuring that the silicone rubber product has a large solubility to oxygen, suitable for testing in low oxygen environments.

[0068] In the above, the amount of hydrochloric acid added can be 1% to 5% of silicon, the amount of deionized water added can be 10% to 30% of silicon, and the amount of toluene added can be 15% to 30% of silicon. The addition ratio of the above raw materials is calculated by molar ratio. The acidic environment formed by the addition of the above hydrochloric acid and deionized water is suitable for the reaction system to undergo a hydrolysis and condensation reaction quickly and stably; the addition of toluene can reduce the viscosity of the oil phase in the product, which is conducive to the separation of the water phase and the oil phase.

[0069] In order to better explain the scheme of the present application, specific examples are provided below to further illustrate the present application. It is worth noting that the reagents, raw materials, consumables and reaction devices used in the examples of the present application are all general commercially available products.

[0070] Example 1

[0071] Preparation of fluorescent glue: Put pentafluorophenyl vinyl silicone oil and pentafluorophenyl hydrogen silicone oil into a reactor, and add platinum catalyst, inhibitor and platinum (II) meta-tetrakis (pentafluorophenyl) porphyrin; wherein the molar ratio of pentafluorophenyl to silicon is 0.2:1, the amount of platinum catalyst and inhibitor added is 0.05% of the amount of pentafluorophenyl silicone oil added; the amount of platinum (II) meta-tetrakis (pentafluorophenyl) porphyrin added is 0.3% of the amount of pentafluorophenyl silicone oil added. The above raw materials are mixed, ground and dispersed to obtain fluorescent glue.

[0072] Preparation of white pentafluorophenyl silicone oil: Put pentafluorophenyl vinyl silicone oil and pentafluorophenyl hydrogen silicone oil into a ball mill, and add platinum catalyst, inhibitor and titanium dioxide; wherein the molar ratio of pentafluorophenyl to silicon is 0.2:1, the amount of platinum catalyst and inhibitor added is 0.05% of the amount of pentafluorophenyl silicone oil added; the amount of titanium dioxide added is 10% of the amount of pentafluorophenyl silicone oil added. The above raw materials are mixed, ground and dispersed to obtain white pentafluorophenyl silicone oil.

[0073] Preparation of black pentafluorophenyl silicone oil: put pentafluorophenyl vinyl silicone oil and pentafluorophenyl hydrogen silicone oil into a ball mill, and add platinum catalyst, inhibitor and carbon black; wherein the molar ratio of pentafluorophenyl to silicon is 0.2:1, the amount of platinum catalyst and inhibitor added is 0.05% of the amount of pentafluorophenyl silicone oil added; the amount of carbon black added is 5% of the amount of pentafluorophenyl silicone oil added; the above raw materials are mixed, ground and dispersed to obtain black pentafluorophenyl silicone oil.

[0074] Preparation of fluorescent cap: take a lens, apply fluorescent glue to one side surface of the lens, and bake in an oven at 80°C for 10 minutes; apply white pentafluorophenyl silicone oil to the fluorescent glue layer, and then bake in an oven at 80°C for 10 minutes; then apply black pentafluorophenyl silicone oil to the white pentafluorophenyl silicone oil layer, and then bake at 120°C for 4 hours to solidify the fluorescent glue, white pentafluorophenyl silicone oil and black pentafluorophenyl silicone oil to form a fluorescent layer, a reflective layer and a light-shielding layer respectively, to obtain a finished fluorescent cap.

[0075] Example 2

[0076] Preparation of fluorescent glue: Put pentafluorophenyl vinyl silicone oil and pentafluorophenyl hydrogen silicone oil into a ball mill, and add platinum catalyst, inhibitor and platinum (II) meta-tetrakis (pentafluorophenyl) porphyrin; wherein the molar ratio of pentafluorophenyl to silicon is 0.1:1, the amount of platinum catalyst and inhibitor added is 0.01% of the amount of pentafluorophenyl silicone oil added; the amount of platinum (II) meta-tetrakis (pentafluorophenyl) porphyrin added is 0.5% of the amount of pentafluorophenyl silicone oil added. The above raw materials are mixed, ground and dispersed to obtain fluorescent glue.

[0077] Preparation of white pentafluorophenyl silicone oil: Put pentafluorophenyl vinyl silicone oil and pentafluorophenyl hydrogen silicone oil into a ball mill, and add platinum catalyst, inhibitor and titanium dioxide; wherein the molar ratio of pentafluorophenyl to silicon is 0.1:1, the amount of platinum catalyst and inhibitor added is 0.01% of the amount of pentafluorophenyl silicone oil added; the amount of titanium dioxide added is 8% of the amount of pentafluorophenyl silicone oil added. The above raw materials are mixed, ground and dispersed to obtain white pentafluorophenyl silicone oil.

[0078] Preparation of black pentafluorophenyl silicone oil: put pentafluorophenyl vinyl silicone oil and pentafluorophenyl hydrogen silicone oil into a ball mill, and add platinum catalyst, inhibitor and carbon black; wherein the molar ratio of pentafluorophenyl to silicon is 0.1:1, the amount of platinum catalyst and inhibitor added is 0.08% of the amount of pentafluorophenyl silicone oil added; the amount of carbon black added is 3% of the amount of pentafluorophenyl silicone oil added; the above raw materials are mixed, ground and dispersed to obtain black pentafluorophenyl silicone oil.

[0079] Preparation of fluorescent cap: take a lens, apply fluorescent glue to one side surface of the lens, and bake in an oven at 80°C for 10 minutes; apply white pentafluorophenyl silicone oil to the fluorescent glue layer, and then bake in an oven at 80°C for 10 minutes; then apply black pentafluorophenyl silicone oil to the white pentafluorophenyl silicone oil layer, and then bake at 100°C for 5 hours to solidify the fluorescent glue, white pentafluorophenyl silicone oil and black pentafluorophenyl silicone oil to form a fluorescent layer, a reflective layer and a light-shielding layer respectively, to obtain a finished fluorescent cap.

[0080] Example 3

[0081] Preparation of fluorescent glue: Put pentafluorophenyl vinyl silicone oil and pentafluorophenyl hydrogen silicone oil into a ball mill, and add platinum catalyst, inhibitor and platinum (II) meta-tetrakis (pentafluorophenyl) porphyrin; wherein the molar ratio of pentafluorophenyl to silicon is 0.05:1, the amount of platinum catalyst and inhibitor added is 0.08% of the amount of pentafluorophenyl silicone oil added; the amount of platinum (II) meta-tetrakis (pentafluorophenyl) porphyrin added is 0.3% of the amount of pentafluorophenyl silicone oil added. The above raw materials are mixed, ground and dispersed to obtain fluorescent glue.

[0082] Preparation of white pentafluorophenyl silicone oil: Put pentafluorophenyl vinyl silicone oil and pentafluorophenyl hydrogen silicone oil into a ball mill, and add platinum catalyst, inhibitor and titanium dioxide; wherein the molar ratio of pentafluorophenyl to silicon is 0.05:1, the amount of platinum catalyst and inhibitor added is 0.05% of the amount of pentafluorophenyl silicone oil added; the amount of titanium dioxide added is 20% of the amount of pentafluorophenyl silicone oil added. The above raw materials are mixed, ground and dispersed to obtain white pentafluorophenyl silicone oil.

[0083] Preparation of black pentafluorophenyl silicone oil: put pentafluorophenyl vinyl silicone oil and pentafluorophenyl hydrogen silicone oil into a ball mill, and add platinum catalyst, inhibitor and carbon black; wherein the molar ratio of pentafluorophenyl to silicon is 0.05:1, the amount of platinum catalyst and inhibitor added is 0.03% of the amount of pentafluorophenyl silicone oil added; the amount of carbon black added is 1% of the amount of pentafluorophenyl silicone oil added; the above raw materials are mixed, ground and dispersed to obtain black pentafluorophenyl silicone oil.

[0084] Preparation of the fluorescent cap: take a lens, apply fluorescent glue to one side surface of the lens, and bake in an oven at 80°C for 10 minutes; apply white pentafluorophenyl silicone oil to the fluorescent glue layer, and then bake in an oven at 80°C for 10 minutes; then apply black pentafluorophenyl silicone oil to the white pentafluorophenyl silicone oil layer, and then bake at 150°C for 4 hours to solidify the fluorescent glue, white pentafluorophenyl silicone oil and black pentafluorophenyl silicone oil to form a fluorescent layer, a reflective layer and a shading layer respectively, to obtain a finished fluorescent cap.

[0085] Comparative Example 1

[0086] Preparation of fluorescent glue: Put pentafluorophenyl vinyl silicone oil and pentafluorophenyl hydrogen silicone oil into a ball mill, and add platinum catalyst, inhibitor and platinum (II) meta-tetrakis (pentafluorophenyl) porphyrin; wherein the molar ratio of pentafluorophenyl to silicon is 0.4:1, the amount of platinum catalyst and inhibitor added is 0.04% of the amount of pentafluorophenyl silicone oil added; the amount of platinum (II) meta-tetrakis (pentafluorophenyl) porphyrin added is 0.2% of the amount of pentafluorophenyl silicone oil added. The above raw materials are mixed, ground and dispersed to obtain fluorescent glue.

[0087] Preparation of white pentafluorophenyl silicone oil: Put pentafluorophenyl vinyl silicone oil and pentafluorophenyl hydrogen silicone oil into a ball mill, and add platinum catalyst, inhibitor and titanium dioxide; wherein the molar ratio of pentafluorophenyl to silicon is 0.4:1, the amount of platinum catalyst and inhibitor added is 0.03% of the amount of pentafluorophenyl silicone oil added; the amount of titanium dioxide added is 15% of the amount of pentafluorophenyl silicone oil added. The above raw materials are mixed, ground and dispersed to obtain white pentafluorophenyl silicone oil.

[0088] Preparation of black pentafluorophenyl silicone oil: put pentafluorophenyl vinyl silicone oil and pentafluorophenyl hydrogen silicone oil into a ball mill, and add platinum catalyst, inhibitor and carbon black; wherein the molar ratio of pentafluorophenyl to silicon is 0.4:1, the amount of platinum catalyst and inhibitor added is 0.04% of the amount of pentafluorophenyl silicone oil added; the amount of carbon black added is 4% of the amount of pentafluorophenyl silicone oil added; the above raw materials are mixed, ground and dispersed to obtain black pentafluorophenyl silicone oil.

[0089] Preparation of fluorescent cap: take a lens, apply fluorescent glue to one side surface of the lens, and bake in an oven at 80°C for 10 minutes; apply white pentafluorophenyl silicone oil to the fluorescent glue layer, and then bake in an oven at 80°C for 10 minutes; then apply black pentafluorophenyl silicone oil to the white pentafluorophenyl silicone oil layer, and then bake at 120°C for 5 hours to solidify the fluorescent glue, white pentafluorophenyl silicone oil and black pentafluorophenyl silicone oil to form a fluorescent layer, a reflective layer and a light-shielding layer respectively, to obtain a finished fluorescent cap.

[0090] Example 4

[0091] When the fluorescent cap is used in the detection device to detect water samples, the most suitable voltage range for the LED lamp is 3.0-3.2 V. If the voltage is too low, the brightness of the LED lamp is insufficient; if the voltage is too high, the LED lamp is prone to aging or even burnout.

[0092] The content of the indicator is limited to be fixed at 0.2%, and the voltage values ​​under constant and applicable fluorescence intensity are measured when the finished fluorescent caps prepared in the above Examples 1 to 3 and Comparative Example 1 are used in the detection device. The test results are shown in Table 1.

[0093] Table 1:

[0094] Example 1 Example 2 Example 3 Comparative Example 1 Molar ratio of pentafluorophenyl to silicon 0.2∶1 0.1∶1 0.05∶1 0.4∶1 Average excitation voltage / V 3.1 3.3 3.7 2.9

[0095] According to Table 1, the voltage value of the fluorescent cap at a constant and applicable fluorescence intensity decreases as the ratio of pentafluorophenyl to silicon increases; in Example 1, when the molar ratio of pentafluorophenyl to silicon is 0.2:1, the voltage of the LED lamp falls within the most suitable range; in Comparative Example 1, when the molar ratio of pentafluorophenyl to silicon is 0.4:1, the voltage of the LED lamp is lower than its most suitable range; and in Examples 2 and 3, the voltage of the LED lamp is slightly higher than its most suitable range; however, the above excitation voltage can obtain a constant and applicable fluorescence value when applied to the measurement. Since the cost of silicone oil containing pentafluorophenyl is relatively high, the present application controls the molar ratio of pentafluorophenyl to silicon to 0.05 to 0.2:1, which can reduce the cost of the product and improve the economy of the product while meeting the detection sensitivity.

[0096] Example 5

[0097] The fluorescent caps prepared in the above-mentioned Examples 1 to 2 and Comparative Example 1 are respectively installed on the sensors of the detection device, and the sensor is placed in a water tank. The water tank has a certain degree of sealing to prevent the outside air from affecting the test results. The liquid level in the water tank is higher than the sensor, and nitrogen and oxygen gases are mixed into the water tank. After the dissolved oxygen is stable, the readings of the detection device are obtained respectively. The same water samples are tested for dissolved oxygen content using commercially available dissolved oxygen probes (I probe, H probe and high-precision portable dissolved oxygen B probe). The test results are shown in Table 2 below.

[0098] Table 2:

[0099]

[0100] In the above table, zero oxygen water is freshly prepared 2g / L sodium sulfite (Na 2 SO 3 )+10mg / L CoCl 2 Solution.

[0101] The high-precision portable dissolution B probe is only used for portable testing and cannot be used for continuous online testing. Otherwise, it may become inaccurate due to aging caused by long-term use of the product.

[0102] The basic principle of measuring dissolved oxygen by fluorescence is to use the property that some substances will produce fluorescence after being excited by light of a specific wavelength, and dissolved oxygen has a quenching effect on fluorescence, that is, oxygen molecules can take away the energy of the excited state of fluorescent substances, resulting in a decrease in fluorescence intensity and fluorescence lifetime. By measuring the change in fluorescence lifetime or fluorescence intensity, the concentration of dissolved oxygen can be indirectly calculated.

[0103] In practical applications, since the fluorescence intensity is easily disturbed by external factors (such as light source stability, detector sensitivity, ambient temperature, etc.), the measurement error is large. Therefore, the method of measuring fluorescence lifetime is usually used to avoid these interferences. Fluorescence lifetime refers to the time required for the fluorescent substance to return to the ground state from the excited state. It is not affected by the intensity of the excitation light and the sensitivity of the detector, but only related to the properties of the fluorescent substance and the concentration of dissolved oxygen.

[0104] Phase difference measurement is an indirect method for measuring fluorescence lifetime. It uses a sine wave modulated light source to excite fluorescent substances. The fluorescence signal emitted by the fluorescent substance will have a lagging phase difference relative to the excitation light signal. This phase difference is proportional to the fluorescence lifetime, so the fluorescence lifetime can be calculated by measuring the phase difference, and then the concentration of dissolved oxygen can be calculated.

[0105] Specifically, when a beam of excitation light of a specific wavelength is irradiated on a fluorescent substance in the form of a sine wave modulation, the fluorescent substance is excited to emit fluorescence of the corresponding wavelength. Due to the quenching effect of dissolved oxygen on fluorescence, the fluorescence lifetime is shortened, resulting in a lagging phase difference between the fluorescence signal and the excitation light signal. This phase difference can be measured through circuit processing such as a phase-locked amplifier, and the relationship between the known fluorescence lifetime and the phase difference can be used to calculate the fluorescence lifetime and the concentration of dissolved oxygen.

[0106] Therefore, when measuring dissolved oxygen, the phase difference and fluorescence lifetime are interrelated, and the phase difference can be used as an effective means to measure the fluorescence lifetime, thereby indirectly calculating the concentration of dissolved oxygen. This method has the advantages of accurate, stable and fast measurement, and has broad application prospects in water quality monitoring, environmental protection and other fields.

[0107] The phase difference reading measured by the detection device increases as the oxygen content decreases. As can be seen from Table 2, when the water tank temperature is 5°C and the high-precision portable dissolved oxygen B probe measures zero oxygen water, the phase difference readings of Example 1 and Example 2 are not much different from those of the I probe and the H probe. When the dissolved oxygen content in the water tank is 0.64 mg / L, the phase difference reading of the detection device containing the fluorescent cap prepared in Example 1 is 39.596, and the phase difference reading of the detection device containing the fluorescent cap prepared in Example 2 is 37.645, while the reading of the I probe is 58.53 and the reading of the H probe is 50.153, that is, when the dissolved oxygen content in the water is lower than 0.5 mg / L, the detection devices prepared in Examples 1 and 2 still have considerable measurement space (the phase difference span from zero oxygen is greater than 20 degrees), while the I probe and the H probe are close to the reading limit when the dissolved oxygen content is 0.64 mg / L (the phase difference span from zero oxygen is less than 3 degrees), and the space for continuing to test the dissolved oxygen content at low levels is limited.

[0108] When the water tank temperature is 20° C., the phase difference readings of the detection devices prepared in Example 1 and Example 2 are also much lower than the phase difference readings of the I probe and the H probe.

[0109] When the water tank temperature is 35°C, the phase difference readings of the detection devices prepared in Examples 1 and 2 are greatly reduced when testing zero oxygen water to testing water samples with a dissolved oxygen content of 0.25 mg / L, while the phase difference readings of the I probe and the H probe do not change much. When the dissolved oxygen content of the water sample is 0.25 mg / L, the phase difference reading of the I probe is as high as 56.85, and the phase difference reading of the H probe is as high as 47.812; when the dissolved oxygen content of the water sample is 0.36 mg / L, the phase difference readings of the detection devices prepared in Examples 1 and 2 are only about 30, while the phase difference reading of the H probe is 46.607, and the phase difference reading of the I probe is as high as 54.72.

[0110] In summary, when the fluorescent cap prepared in the present application is used to detect the dissolved oxygen content in water samples, whether at 5°C, 20°C or 35°C, it is more suitable for testing water samples with low dissolved oxygen content, especially water samples with dissolved oxygen content lower than 1 mg / L, compared with the existing H probe and I probe.

[0111] It is understandable that those skilled in the art can make equivalent substitutions or changes based on the technical solution and application concept of the present application, and all these changes or substitutions should fall within the protection scope of the claims attached to the present application.

Claims

1. A fluorescent cap for measuring dissolved oxygen, characterized in that: include: The invention discloses a lens, and a fluorescent layer, a reflecting layer and a light shielding layer sequentially covering one side of the lens; wherein the fluorescent layer is formed by dispersing and solidifying raw materials including pentafluorophenyl vinyl silicone oil, pentafluorophenyl hydrogen-containing silicone oil, platinum catalyst, inhibitor and platinum (II) meta-tetrakis (pentafluorophenyl) porphyrin.

2. The fluorescent cap according to claim 1, characterized in that: The thicknesses of the fluorescent layer, the reflective layer and the light shielding layer are 5-50 μm respectively.

3. The fluorescent cap according to claim 1 or 2, characterized in that: The pentafluorophenyl vinyl silicone oil is prepared by hydrolysis and condensation of dimethoxybis(pentafluorophenyl)silane, dimethyldiethoxysilane and methylvinyldiethoxysilane.

4. The fluorescent cap according to claim 3, characterized in that: The pentafluorophenyl hydrogen-containing silicone oil is prepared by hydrolysis and condensation of dimethoxybis(pentafluorophenyl)silane, dimethyldiethoxysilane and methyldiethoxysilane.

5. The fluorescent cap according to claim 4, characterized in that: The molar ratio of pentafluorophenyl, silicon and vinyl in the pentafluorophenyl vinyl silicone oil is 0.05-0.2:1:0.001-0.005; and / or, The molar ratio of pentafluorophenyl group, silicon group and silicon hydrogen group in the pentafluorophenyl hydrogen-containing silicone oil is 0.05-0.2:1:0.001-0.

005.

6. The fluorescent cap according to claim 1, characterized in that: The reflective layer is formed by dispersing and curing raw materials including pentafluorophenyl vinyl silicone oil, pentafluorophenyl hydrogen silicone oil, platinum catalyst, inhibitor and titanium dioxide; The light shielding layer is formed by dispersing and curing raw materials including pentafluorophenyl vinyl silicone oil, pentafluorophenyl hydrogen-containing silicone oil, a platinum catalyst, an inhibitor and carbon black.

7. The fluorescent cap according to claim 6, characterized in that: The content of the titanium dioxide is 10% to 20% of the total amount of pentafluorophenyl vinyl silicone oil and pentafluorophenyl hydrogen silicone oil in the reflective layer; the content of the carbon black is 5% to 10% of the total amount of pentafluorophenyl vinyl silicone oil and pentafluorophenyl hydrogen silicone oil in the light-shielding layer.

8. The fluorescent cap according to claim 6, characterized in that: The mass ratio of pentafluorophenyl vinyl silicone oil to pentafluorophenyl hydrogenated silicone oil in the composition for preparing the fluorescent layer, the reflective layer and the light shielding layer is 1:

1.

9. A method for preparing a fluorescent cap, characterized in that: The fluorescent cap is the fluorescent cap according to any one of claims 1 to 8, and the preparation method comprises: Prepare fluorescent glue forming the fluorescent layer, white pentafluorophenyl silicone oil forming the reflective layer, and black pentafluorophenyl silicone oil forming the light-shielding layer respectively; Take a lens, apply the fluorescent glue to one side of the lens, and bake it to form the fluorescent layer; Applying the white pentafluorophenyl silicone oil onto the fluorescent layer and baking to form the reflective layer; The black pentafluorophenyl silicone oil is coated on the reflective layer and baked to solidify the fluorescent glue, the white pentafluorophenyl silicone oil and the black pentafluorophenyl silicone oil to obtain the fluorescent cap.

10. A detection device for measuring dissolved oxygen, characterized in that: The detection device comprises the fluorescent cap as described in any one of claims 1 to 8.

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