fluorescent test solution

Abstract

A fluorescent examination liquid containing water, riboflavin or rhodamine (B) as a fluorescent pigment dissolved in the water, and a deterioration preventive agent for preventing deterioration of the fluorescent pigment due to light, the deterioration preventive agent containing a p-hydroxybenzoic acid ester.

Description

Technical Field

[0001] This invention relates to a fluorescent inspection solution for leak detection. Background Technology

[0002] Leak checks are sometimes performed on machines or piping systems that require a certain degree of airtightness. One method for leak checking is using a test solution containing fluorescent dye (hereinafter referred to as a fluorescent test solution).

[0003] For example, Japanese Patent Application Publication No. 2018-132305 describes a system for supplying a mist containing a fluorescent testing solution to a pharmaceutical working chamber for leak detection. Furthermore, the aforementioned document describes the use of riboflavin or sodium riboflavin phosphate as the fluorescent testing solution.

[0004] In addition, it is known that an aqueous solution of Rhodamine B is used as a fluorescent testing solution for leak detection (e.g., Japanese Patent Application Publication No. 2000-107575). Summary of the Invention

[0005] Aqueous solutions of fluorescent dyes such as riboflavin and rhodamine B may gradually degrade during storage due to exposure to indoor light. Therefore, they are difficult to store for long periods and require the preparation of fluorescent test solutions by dissolving riboflavin and rhodamine B powder in water just before use, which involves complex preparation procedures.

[0006] Furthermore, in facilities where inspections using fluorescent testing solutions are performed regularly, it is necessary to wipe up any leaked solution from the leak point until the next inspection. However, in equipment such as piping systems in factories and air conditioning systems in buildings, the cleaning of fluorescent testing solutions can be difficult, depending on the location of the leak.

[0007] Therefore, there is a need for a fluorescent testing solution that improves the stability of the fluorescent testing solution to indoor light while allowing the fluorescence to decompose and disappear after an appropriate period of time, thus eliminating the need for cleaning.

[0008] The present invention aims to solve the above-mentioned problems.

[0009] The following disclosure relates to a fluorescent testing solution comprising water, a fluorescent dye dissolved in the water, and a degradation inhibitor to prevent the fluorescent dye from deteriorating due to light, the degradation inhibitor being a paraben.

[0010] According to the above-mentioned viewpoints, the fluorescent dye, being an aqueous solution, exhibits improved light stability during storage, and the rate of photodegradation is suppressed. Furthermore, upon release into the environment, the fluorescent dye decomposes within hours to weeks, and the fluorescence disappears, thus eliminating the need for post-leakage cleaning. Therefore, the fluorescent dye solution described above eliminates the need for preparation of the solution before leak detection and post-leakage cleaning, making leak detection more labor-saving.

[0011] The above-mentioned objects, features, and advantages can be readily understood from the following description of embodiments illustrated with reference to the accompanying drawings. Attached Figure Description

[0012] [ Figure 1 ] Figure 1 This is a table showing the composition, fluorescence color, and evaluation results of the first to sixth fluorescent test solutions of Experimental Example 1, as well as the wastewater discharge standards.

[0013] [ Figure 2 ] Figure 2 A is a photograph taken during a leak inspection, showing the leak site illuminated with ultraviolet light. Figure 2 B is selfie Figure 2 A1 weeks after exposure to ultraviolet light and the photograph taken.

[0014] [ Figure 3 ] Figure 3 Photograph A shows the appearance changes of an aqueous riboflavin solution (concentration 20 ppm) caused by fluorescent lamp irradiation (Experimental Example 2). Figure 3 B is a photograph showing the appearance changes of an aqueous solution of riboflavin (concentration 20 ppm) caused by ultraviolet light irradiation (Experimental Example 3).

[0015] [ Figure 4 ] Figure 4 This is a photograph showing the appearance changes caused by ultraviolet light irradiation of an aqueous solution of riboflavin (concentration 5-20 ppm) with added methylparaben in the range of 0-100 ppm (Experimental Example 4).

[0016] [ Figure 5 ] Figure 5 A is shown in Figure 4 A graph showing the change in fluorescence intensity of an aqueous solution containing 5 ppm riboflavin relative to irradiation time. Figure 5 B is shown in Figure 4 A graph showing the change in fluorescence intensity of an aqueous solution containing 10 ppm riboflavin relative to irradiation time.

[0017] [ Figure 6 ] Figure 6 It is shown in Figure 4A graph showing the change in fluorescence intensity of an aqueous solution with a riboflavin concentration of 20 ppm relative to irradiation time.

[0018] [ Figure 7 ] Figure 7 This is a photograph showing the appearance changes caused by ultraviolet light irradiation of an aqueous solution of Rhodamine B (concentration 1-5 ppm) with added methylparaben in the range of 0-100 ppm (Experimental Example 5).

[0019] [ Figure 8 ] Figure 8 A is shown in Figure 7 A graph showing the change in fluorescence intensity of a 1 ppm Rhodamine B aqueous solution relative to irradiation time. Figure 8 B is shown in Figure 7 A graph showing the change in fluorescence intensity of Rhodamine B at a concentration of 3 ppm in an aqueous solution relative to irradiation time.

[0020] [ Figure 9 ] Figure 9 It is shown in Figure 7 A graph showing the change in fluorescence intensity of a 5 ppm Rhodamine B aqueous solution relative to irradiation time. Detailed Implementation

[0021] The fluorescent inspection solution of this embodiment is used, for example, for leak detection in a factory piping system. The fluorescent inspection solution is sprayed into compressed air in a mist form and introduced into the piping system along with the compressed air. The mist-like fluorescent inspection solution spreads throughout the piping system with the flow of compressed air. For example, when a connection or other part of the piping becomes loose, compressed air leaks from that part. The fluorescent inspection solution, along with the leaking compressed air, flows outward from the leak point such as the connection or other leak location, staining the leak point with a fluorescent dye. The leak point stained by the fluorescent inspection solution can be easily detected visually by irradiating it with ultraviolet light, such as a black light lamp.

[0022] Furthermore, the examples above do not limit the application of fluorescent inspection solutions to piping systems. Fluorescent inspection solutions can also be used for leak detection in water pipes, food manufacturing equipment, or air conditioning pipes in buildings, and other equipment requiring airtightness. In addition, fluorescent inspection solutions can be added to pressurized air in a mist form, or they can be introduced into piping systems as a liquid diluted to a specified ratio.

[0023] The fluorescent testing solution of this embodiment is an aqueous solution prepared by dissolving a fluorescent dye and a degradation inhibitor in water as a solvent. The fluorescent dye is composed of a substance that is highly safe for human use and is susceptible to decomposition by microorganisms, by reaction with atmospheric oxygen, or by visible or ultraviolet light in the environment. Depending on the application, the fluorescent dye may be selected as, for example, food coloring or a substance contained in food. Furthermore, depending on the application, the fluorescent dye may be selected as a substance with low irritation upon skin contact. Blue, green, and red fluorescent dyes can be used as fluorescent dyes.

[0024] Blue fluorescent dyes are dyes that absorb ultraviolet light and emit blue fluorescence in the wavelength range of 360–500 nm. Examples of blue fluorescent dyes used in the fluorescent testing solution of this embodiment include flavin derivatives, quinine, pyrene, anthocyanins, and umbelliferones, which will be described later. These blue fluorescent dyes can be used alone or in combination.

[0025] Among blue fluorescent pigments, a mixture of quinine and flavin derivatives is suitable due to its excellent safety profile for humans and its bright blue fluorescence with high visibility. Quinine is used as a bittering agent in soft drinks (tonic water), and it is highly safe for humans even when ingested orally, exhibiting excellent biodegradability and atmospheric decomposition. Furthermore, the flavin derivatives of this embodiment are derivatives based on riboflavin, which has a flavin backbone. Such flavin derivatives are, for example, fluorescent pigments obtained by photodecomposing riboflavin, containing formylmethylflavin and a photopigment as main components. These substances are produced through the photodecomposition of riboflavin (vitamin B2), are contained in food, are safe even when ingested orally, and are rapidly decomposed in the environment.

[0026] Green fluorescent pigments are pigments that absorb ultraviolet light and emit green fluorescence in the wavelength range of 500-570 nm. Examples of green fluorescent pigments include riboflavin (vitamin B2), fluorescein, acridine orange, flame red B (Red 104), and lycopene. These green fluorescent pigments can be used alone or in combination. Among them, riboflavin, as vitamin B2, is contained in food and has high safety for human use. It also exhibits excellent biodegradability and atmospheric decomposition, making it suitable for the fluorescent test solution of this embodiment. In this embodiment, it is suitable for the fluorescent test solution containing riboflavin as a green fluorescent pigment to contain riboflavin at a concentration of 5-27 ppm. In one suitable example, the fluorescent test solution may also contain riboflavin as a green fluorescent pigment at a concentration of 5-20 ppm.

[0027] Red fluorescent pigments are pigments that absorb ultraviolet light and emit red fluorescence in the wavelength range of 590–830 nm. Examples of red fluorescent pigments include chlorophyll, rhodamine B, acid red (Red 106), eosin, cochineal pigment, tannin, phycocyanin (spirulina pigment), safflower pigment, phycoerythrin, erythrosine (Red 3), and rose red (Red 105). These red fluorescent pigments can be used alone or in combination. In this embodiment, it is suitable for the fluorescent test solution containing rhodamine B as a red fluorescent pigment to contain rhodamine B at a concentration of 1–123 ppm. In a suitable example, the fluorescent test solution may also contain rhodamine B as a red fluorescent pigment at a concentration of 1–5 ppm.

[0028] Furthermore, the fluorescent testing solution can also be formulated to emit blue-green fluorescence by including blue and green fluorescent pigments. Additionally, the fluorescent testing solution can be formulated to emit orange or yellow fluorescence by combining green and red fluorescent pigments. Further, the fluorescent testing solution can also be formulated to emit peach or purple fluorescence by combining blue and red fluorescent pigments. The fluorescent testing solution of this embodiment allows for the appropriate selection of the fluorescent color with the best visibility under the testing environment.

[0029] Deterioration inhibitors suppress light-induced degradation and deterioration of the fluorescent dye contained in the fluorescent test solution as an aqueous solution. Parabens can be used as deterioration inhibitors. Furthermore, deterioration inhibitors can also have preservative functions, preventing the decomposition of the fluorescent dye as an aqueous solution by microorganisms. To enhance this preservative function, isothiazolinone derivatives can be added in addition to parabens.

[0030] In one embodiment, parabens can be used as deterioration preventers. Examples of parabens suitable for use in fluorescent testing solutions include methylparaben, ethylparaben, propylparaben, isopropylparaben, butylparaben, isobutylparaben, heptylparaben, and benzylparaben. One or a combination of the parabens listed above can be used as a deterioration preventer.

[0031] In other embodiments, isothiazolinone derivatives may be further added to improve the anti-corrosion function. As isothiazolinone derivatives, any one or a combination of methylisothiazolinone (MI), methylchloroisothiazolinone (MCI), octylisothiazolinone (OI), dichlorooctylisothiazolinone (DOCI), and benzisothiazolinone (BI) may be used.

[0032] In fluorescent testing solutions, depending on the application, the degradation inhibitor can be used at concentrations of 10 ppm or less, or 100 ppm or less. Methylparaben at concentrations of 10 ppm or less meets the standards for use as a food additive and exhibits excellent safety for oral ingestion, making it suitable for fluorescent testing solutions, for example, food processing machinery. Furthermore, degradation inhibitors at concentrations of 100 ppm or less meet the standards for use in pharmaceuticals and medical devices, and do not cause irritation even upon skin contact, enabling a highly safe fluorescent testing solution. Additionally, if the concentration of the degradation inhibitor is below 100 ppm, the rapid decomposition of fluorescent pigments caused by light in the post-use environment is not hindered. Therefore, the fluorescent testing solution of this embodiment is suitable for simplifying cleanup operations after leak detection.

[0033] (Experimental Example 1)

[0034] In this experimental example, the composition of the fluorescent test solution, the evaluation of the wastewater discharge standard, and the evaluation of the disappearance of fluorescence were carried out.

[0035] Figure 1 This table shows the composition, fluorescence color, and evaluation results of the first to sixth fluorescent test solutions in this experimental example, as well as their wastewater discharge standards. The first fluorescent test solution is an aqueous solution containing 27 ppm riboflavin (vitamin B2) as the first fluorescent dye. It also contains 100 ppm methylparaben as a deterioration inhibitor. The first fluorescent test solution emits a pale yellow fluorescence with a slight green tint. The COD (chemical oxygen demand) and BOD (biochemical oxygen demand), which indicate the degree of water pollution, of the first fluorescent test solution are below the standard value of 160 mg / L for wastewater discharge. Therefore, it can be confirmed that the first fluorescent test solution is suitable for wastewater discharge.

[0036] The second fluorescent test solution is an aqueous solution containing 18 ppm riboflavin as the primary fluorescent dye, 6 ppm quinine (a blue fluorescent dye) as the secondary fluorescent dye, and 100 ppm methylparaben as a deterioration inhibitor. The second fluorescent test solution emits a yellow-green fluorescence. Since both the COD and BOD of the second fluorescent test solution are below 160 mg / L, it can be confirmed that it can flow into wastewater.

[0037] The third fluorescent test solution is an aqueous solution containing 27 ppm riboflavin as the first fluorescent pigment and 2.7 ppm Acid Red as the second fluorescent pigment. As a deterioration preventer, the third fluorescent test solution contains 100 ppm methylparaben. The third fluorescent test solution emits a slightly reddish-yellow fluorescence. The COD and BOD of the third fluorescent test solution are both below 160 mg / L, confirming that it can be used in wastewater.

[0038] The fourth fluorescent test solution is an aqueous solution containing 20 ppm of a flavin derivative as the first fluorescent pigment (a blue fluorescent pigment), 7 ppm of quinine as the second fluorescent pigment (a blue fluorescent pigment), and 100 ppm of methylparaben as a deterioration inhibitor. The fourth fluorescent test solution emits blue fluorescence. Since both the COD and BOD of the fourth fluorescent test solution are below 160 mg / L, it can be confirmed that it can flow into wastewater.

[0039] The fifth fluorescent test solution contains 123 ppm of the red fluorescent dye Rhodamine B as the primary fluorescent dye and 100 ppm of methylparaben as a degradation inhibitor. The fifth fluorescent test solution emits an orange (with a yellowish-red tint) fluorescence. The COD and BOD of the fifth fluorescent test solution are both below 160 mg / L, confirming its suitability for wastewater discharge.

[0040] The sixth fluorescent test solution contains 210 ppm of Acid Red as the primary fluorescent dye and 100 ppm of methylparaben as a degradation inhibitor. The sixth fluorescent test solution emits red fluorescence. Both the COD and BOD of the sixth fluorescent test solution are below 160 mg / L, confirming its suitability for use in wastewater.

[0041] Next, the results of an investigation into the decomposability of fluorescent dyes in the atmosphere are explained. A loose test pipe, with a potential leak point installed at the pipe joint, was used to supply a mist of fluorescent testing solution along with compressed air. In this experimental example, a fluorescent testing solution containing riboflavin at a concentration of 5 ppm as the fluorescent dye and methylparaben at a concentration of 10 ppm as a degradation inhibitor was used.

[0042] exist Figure 2 In section A, shown by the hollow elliptical frame, fluorescent testing fluid leaks from a pipe joint. Ultraviolet light from a black light lamp is shone onto the leak. As shown, the leaked fluorescent testing fluid emits bright fluorescence, making the leak easily visible.

[0043] Next, regarding Figure 2 Piping and connectors of component A were left untreated with fluorescent testing solution for one week. Ultraviolet light was then irradiated onto the same areas to confirm the presence or absence of fluorescence. The results showed... Figure 2 As shown in B. Figure 2 As shown in Figure B, the fluorescence of the fluorescent testing solution in the connector disappears, and the fluorescent pigment (riboflavin) is rapidly decomposed. This confirms that the fluorescent pigment in the fluorescent testing solution of this embodiment is decomposed within a short period of less than one week.

[0044] (Experimental Example 2)

[0045] In this experimental example, the photodegradation rate of an aqueous solution containing riboflavin as a fluorescent dye at a concentration of 20 ppm was evaluated. Irradiation using a fluorescent lamp was conducted at an illuminance of 750 lx (lux). This illuminance corresponds to the illuminance required in typical visual work environments such as factories and offices as specified in JIS Z 9110 (General Guidelines for Illumination Standards), and is equivalent to typical indoor lighting illuminance. Irradiation lasted from 0 to 1200 minutes. In this experimental example, at specified intervals, the aqueous solution was irradiated with ultraviolet light, and the fluorescence emitted from the aqueous solution was captured by a camera.

[0046] exist Figure 3 A shows the appearance change of the riboflavin aqueous solution obtained from Experimental Example 2. When the riboflavin aqueous solution was continuously illuminated by light from a fluorescent lamp, the fluorescence of the aqueous solution gradually changed from a bright yellow-green to a bluish tint. Therefore, it can be confirmed that the riboflavin aqueous solution without a degradation inhibitor degrades in a relatively short time.

[0047] (Experimental Example 3)

[0048] In this experimental example, an experiment was conducted to test the rate of photodegradation. Similar to Example 2, an aqueous solution containing riboflavin at a concentration of 20 ppm was used. In this example, instead of a fluorescent lamp, ultraviolet light irradiation was performed at 10.0 mW / cm². 2 The intensity of ultraviolet light irradiation was measured. In this experimental example, fluorescence emitted from the aqueous solution was photographed at predetermined intervals.

[0049] exist Figure 3 B shows the appearance change of the riboflavin aqueous solution obtained in Experiment 3. This experiment confirms that irradiating the riboflavin aqueous solution with ultraviolet light for 60 minutes resulted in the same change in fluorescence color as irradiation with a fluorescent lamp for 1200 minutes in Experiment 2. Therefore, it appears that ultraviolet light irradiation accelerates the photodegradation rate by approximately 20 times compared to irradiation with a fluorescent lamp.

[0050] (Experimental Example 4)

[0051] In this experimental example, the following fluorescent test solutions were prepared: one type of paraben, namely methylparaben, was added to each riboflavin aqueous solution (concentrations of 5 ppm, 10 ppm, and 20 ppm) as a degradation inhibitor. The amounts of methylparaben added were 0 ppm, 50 ppm, and 100 ppm, resulting in a total of nine fluorescent test solutions.

[0052] The rate of photodegradation was evaluated by irradiating these fluorescent test solutions with ultraviolet light. The intensity of the ultraviolet light from the ultraviolet lamp was 10.0 mW / cm². 2 In this experimental example, the fluorescence of the fluorescent test solution was also photographed with a camera at specified intervals.

[0053] exist Figure 4 The figure shows the appearance changes of the fluorescent test solution in this experimental example. As shown in the figure, no change was observed in the fluorescence color in the initial state up to a concentration of methylparaben up to 100 ppm. Therefore, it can be confirmed that the addition of methylparaben does not affect the fluorescence color of the riboflavin aqueous solution.

[0054] Next, based on Figure 4 From the image, the G luminance value corresponding to the green fluorescence of each fluorescent test solution was calculated. The G luminance value was extracted from the R, G, and B luminance values ​​of the pixels in the bottle portion of the image and averaged. The G luminance value of each fluorescent test solution was normalized such that the G luminance value at the start of irradiation was 1. The change of the G luminance value with respect to irradiation time was... Figure 5 A~ Figure 6 As shown in the image.

[0055] like Figure 5 A~ Figure 6 The results show that, regardless of the riboflavin concentration, the addition of methylparaben tends to suppress the decrease in the G brightness value corresponding to green fluorescence. Furthermore, regarding the suppression of the decrease in G brightness value, a fluorescent test solution containing methylparaben at a concentration of 100 ppm is more effective than one containing methylparaben at a concentration of 50 ppm. These results confirm that methylparaben is effective in suppressing the light degradation of riboflavin aqueous solutions (fluorescent test solutions).

[0056] Furthermore, even with a fluorescent inspection solution containing methylparaben at a concentration of 100 ppm, a decrease in the G brightness value occurred after sufficient light exposure. This result confirms that even with the addition of methylparaben to the riboflavin aqueous solution, the fluorescent inspection solution decomposes after sufficient exposure to light following a leak test. Therefore, this experimental example confirms that the addition of methylparaben to the fluorescent inspection solution does not hinder the decomposition of fluorescent dyes by exposure after a leak test, thus simplifying the cleaning process.

[0057] (Experimental Example 5)

[0058] In this experimental example, fluorescent test solutions were prepared by adding methylparaben as a degradation inhibitor to various Rhodamine B aqueous solutions (concentrations of 1 ppm, 3 ppm, and 5 ppm). A total of nine fluorescent test solutions were prepared by adding methylparaben at concentrations of 0 ppm, 50 ppm, and 100 ppm.

[0059] The rate of photodegradation was evaluated by irradiating these fluorescent test solutions with ultraviolet light. The intensity of the ultraviolet light from the ultraviolet lamp was 10.0 mW / cm². 2 In this experimental example, the fluorescence of the fluorescent test solution was also photographed with a camera at specified intervals.

[0060] exist Figure 7 The figure shows the appearance changes of the fluorescent test solution in this experimental example. As shown in the figure, no change was observed in the fluorescence color in the initial state up to 100 ppm of methylparaben. Therefore, it can be confirmed that the addition of methylparaben does not affect the orange fluorescence color of the Rhodamine B aqueous solution.

[0061] Next, based on Figure 7 For each fluorescent test solution, the R brightness value of the red fluorescence, which best reflects the characteristic fluorescent color, was determined from the images. The R brightness value was extracted from the R, G, and B brightness values ​​of the pixels in the bottle portion of the image and averaged. The R brightness values ​​were normalized such that the R brightness value at the start of irradiation was 1. The variation of these R brightness values ​​with irradiation time is shown in... Figure 8 A~ Figure 9 middle.

[0062] like Figure 8 A~ Figure 9The results show that, regardless of the concentration of Rhodamine B, the decrease in R brightness value was suppressed by adding methylparaben. Furthermore, the fluorescent test solution containing methylparaben at a concentration of 100 ppm showed a greater effect in suppressing the decrease in R brightness value compared to a fluorescent test solution containing methylparaben at a concentration of 50 ppm. These results confirm that methylparaben is effective in suppressing the light degradation of Rhodamine B aqueous solution (fluorescent test solution).

[0063] Furthermore, it was confirmed that even with a fluorescent inspection solution containing methylparaben at a concentration of 100 ppm, the R brightness value decreased and fluorescence was lost after sufficient light exposure. This result confirms that even with the addition of methylparaben to the Rhodamine B aqueous solution, the fluorescent dye is decomposed by placing the solution in a light-exposed environment for a sufficient time after leak inspection. Therefore, this experimental example also confirms that adding methylparaben to the fluorescent inspection solution does not hinder the decomposition of the fluorescent dye caused by post-leak inspection placement, making cleaning operations easier.

[0064] In addition to the above disclosure, the following notes are further disclosed.

[0065] (Note 1)

[0066] One of the aforementioned disclosed aspects is a fluorescent testing solution comprising water, a fluorescent dye dissolved in the water, and a degradation inhibitor to prevent the fluorescent dye from deteriorating due to light, wherein the degradation inhibitor is a paraben. The aforementioned fluorescent testing solution can prevent the degradation of the fluorescent dye caused by ultraviolet light during storage.

[0067] (Note 2)

[0068] The fluorescent testing solution described in Appendix 1 may also contain methylparaben as a degradation inhibitor at a concentration of 50 ppm or higher. This fluorescent testing solution can prevent the degradation of fluorescent dyes due to ultraviolet light during storage, and after being released into the environment, the fluorescent dyes decompose and the fluorescence disappears within several hours to several days. Therefore, the fluorescent testing solution described above simplifies the preparation of the fluorescent testing solution before leak testing and the cleaning operation after leak testing, making leak testing more labor-saving.

[0069] (Note 3)

[0070] The fluorescent testing solution described in Appendix 2 may also contain methylparaben as a degradation preventer at a concentration of 100 ppm or less. This fluorescent testing solution meets BOD and COD emission standards, therefore the used fluorescent testing solution can be discharged into wastewater for treatment.

[0071] (Note 4)

[0072] The fluorescent test solution described in any of Notes 1 to 3 may also contain riboflavin as the fluorescent pigment at a concentration of 5 to 27 ppm. This fluorescent test solution exhibits excellent safety for human use and prevents degradation due to ultraviolet light during storage. Furthermore, since this fluorescent test solution is decomposed upon sufficient light irradiation, post-use cleaning is unnecessary, making it suitable.

[0073] (Note 5)

[0074] The fluorescent testing solution described in any of Notes 1 to 3 may also contain Rhodamine B as the fluorescent dye at a concentration of 1 to 123 ppm. This fluorescent testing solution exhibits excellent safety for human use and prevents degradation due to ultraviolet light during storage. Furthermore, since this fluorescent testing solution is decomposed upon sufficient light irradiation, post-use cleaning is unnecessary, making it suitable.

[0075] This disclosure has been described in detail, but it is not limited to the various embodiments described above. Various additions, substitutions, modifications, and partial deletions can be made to these embodiments without departing from the spirit of this disclosure, or from the spirit of this disclosure derived from the claims and their equivalents. Furthermore, these embodiments can also be implemented in combination. For example, in the embodiments described above, the order of actions and the order of processes are shown as examples, but are not limited to these. Similarly, the use of numerical values ​​or mathematical formulas in the description of the embodiments described above is also relevant.

Claims

1. A fluorescent testing solution, characterized in that, Includes: water, Fluorescent pigments dissolved in the water, and A degradation inhibitor to prevent the fluorescent dye from deteriorating due to light. The degradation preventer is paraben.

2. The fluorescent testing solution according to claim 1, characterized in that, Methylparaben contains methylparaben as the degradation preventer at a concentration of 50 ppm or higher.

3. The fluorescent testing solution according to claim 2, characterized in that, The methylparaben is contained at a concentration of less than 100 ppm.

4. The fluorescent testing solution according to any one of claims 1 to 3, characterized in that, It contains riboflavin as the fluorescent pigment at a concentration of 5 to 27 ppm.

5. The fluorescent testing solution according to any one of claims 1 to 3, characterized in that, Rhodamine B, as the fluorescent dye, is contained at a concentration of 1 to 123 ppm.

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