JP5432014B2 - Method for measuring volatile organic substances - Google Patents

Description

  The present invention relates to a method for measuring a volatile organic substance for measuring a volatile organic substance.

  Volatile organic compounds (VOC) are contained in paints, fragrances, antiseptics, fungicides, fragrances, pigments, etc. to prevent decay and reduce human discomfort due to odors. It is also used in many scenes such as industrial fields.

  On the other hand, in recent years, volatile organic substances have become an epidemiological problem with excessive long-term exposure, and some substances are regulated. In addition, the generation of high-concentration volatile organic substances in the room is considered to be one of the causes of sick house syndrome for people with chemical sensitivity. In addition, it is a cause of groundwater contamination and soil contamination due to penetration into groundwater and accumulation in soil.

  For this reason, various sensors and detector tubes that easily detect the concentration of volatile organic substances have been proposed for environmental measurement. For example, a small gas sensor that measures a volatile organic substance using a semiconductor is sold (see Non-Patent Document 1). According to this gas sensor, volatile organic substances can be easily measured. However, this sensor cannot identify (qualify) volatile organic substances.

  There is also a technique for detecting aldehydes in volatile organic substances using a Schiff reagent (see Patent Documents 1 and 2). Patent Document 1 describes that formaldehyde or malondialdehyde can be detected using basic fuchsin, sodium bisulfite, and phosphoric acid. Patent Document 2 describes that formaldehyde can be detected using a Schiff reagent and phosphoric acid or concentrated sulfuric acid. However, even with these measurement techniques, it is impossible to qualify substances.

  For the above technique, a method using a detector tube is known as a measurement capable of qualitatively determining a substance. However, with qualitative analysis using detector tubes, detector tubes corresponding to the target substance must be used, and it is necessary to prepare the number of detector tubes corresponding to the number of target substances. It's not easy.

International Publication No. WO2004 / 111635 JP 2008-224590 A Japanese Patent No. 3639123

http://www.figaro.co.jp/make_html/item_2_sen_112227.html

  As described above, for example, the related technology cannot qualify a plurality of volatile organic substances present in the environment, and even a detector tube system capable of qualification cannot measure quickly. There was a problem.

  The present invention has been made in order to solve the above-described problems, and an object of the present invention is to make it possible to more quickly qualify a plurality of volatile organic substances.

In the method for measuring a volatile organic substance according to the present invention, a first step of exposing a detection solution comprising an aqueous solution in which a Schiff reagent and an acid are dissolved to a gas to be measured, and after the first step, the absorbance of the detection solution is measured. Propionaldehyde, n-nonylaldehyde, benzaldehyde, styrene, α-pinene, limonene, and 2-methyl-3-butene-2- contained in the gas depending on the second step to be obtained and the state of the obtained absorbance spectrum And a third step of qualifying a volatile organic substance selected from among all .

  In the method for measuring a volatile organic substance, in the first step, a sensing element in which a sensing solution is placed in a hole of a transparent porous body made of glass is exposed to gas, and in the second step, the light transmittance of the sensing element is measured. The absorbance may be obtained by measuring.

  In the method for measuring a volatile organic material, in the third step, qualitative analysis may be performed by comparing a spectrum obtained by comparing a known spectrum obtained for a known volatile organic material.

Further, the method for measuring a volatile organic substance according to the present invention measures a first detection solution comprising an aqueous solution in which a Schiff reagent and sulfuric acid are dissolved, and a second detection solution comprising an aqueous solution in which the Schiff reagent and phosphoric acid are dissolved. A first step of exposing to the target gas, a second step of visually observing the color change of the first detection solution and the color change of the second detection solution, and the color change and the second detection of the first detection solution the color change of the solution, contained in a gas, formaldehyde, base lens aldehydes, styrene, alpha - pinene, limonene, and 2-methyl-3-buten-2-volatile organic substances selected from among all And at least a third step for qualitatively.

In the volatile organic substance measuring method, in the first step, the first sensing element and the second sensing element in which the first sensing solution and the second sensing solution are arranged in the pores of a transparent porous body made of glass are contained in the gas. In the second step, the color change of the first detection solution and the color change of the second detection solution may be obtained by visually observing the color change of the first detection device and the second detection device.

Further, in the method for measuring a volatile organic substance according to the present invention, a detection element made of an aqueous solution in which a Schiff reagent and an acid are dissolved is used as a gas to be measured. After the first step exposed to the inside, and after the first step, the color image data of the sensing element obtained by imaging the sensing element with the color imaging device is composed of density values of each color of RGB constituting the color image data. Second step of obtaining RGB analysis results, and formaldehyde, propionaldehyde, n-nonylaldehyde, benzaldehyde, styrene, α-pinene, limonene, and 2-methyl-3 contained in the gas based on the obtained RGB analysis results A third step of qualifying a volatile organic substance selected from buten-2-ol.

In the volatile organic substance measuring method, in the first step, a first sensing element comprising an aqueous solution in which a Schiff reagent and sulfuric acid are dissolved is disposed in a hole of a transparent porous body made of glass; In the second step, the second sensing solution comprising an aqueous solution in which the Schiff reagent and sulfuric acid and sulfuric acid are dissolved is exposed to the gas to be measured, which is disposed in the hole of the transparent porous body made of glass. The first RGB analysis result is obtained from the first sensing element, the second RGB analysis result is obtained from the second sensing element, and in the third step, the first RGB analysis result and the second RGB analysis result are compared with each other in the gas. Qualitative analysis of volatile substances contained in the substrate may be performed.

  As described above, according to the present invention, the volatile organic substance is qualitatively determined according to the state of color change such as the absorbance spectrum of the detection solution composed of the aqueous solution in which the Schiff reagent and the acid are dissolved. An excellent effect is obtained that the qualification of a plurality of volatile organic substances can be performed more quickly.

FIG. 1A is a process diagram for describing a method for measuring a volatile organic substance in Embodiment 1 of the present invention. FIG. 1B is a process diagram for describing a method for measuring a volatile organic substance in Embodiment 1 of the present invention. FIG. 2A is a process diagram for explaining a method for measuring a volatile organic substance in Embodiment 2 of the present invention. FIG. 2B is a process diagram for describing a method for measuring a volatile organic substance in Embodiment 2 of the present invention. FIG. 2C is a process diagram for describing a method for measuring a volatile organic substance in Embodiment 2 of the present invention. FIG. 2D is a process diagram for describing a method for measuring a volatile organic substance in Embodiment 2 of the present invention. FIG. 2E is a process diagram for describing a method for measuring a volatile organic substance in Embodiment 2 of the present invention. FIG. 3 is a characteristic diagram showing the results of absorbance measurement (absorbance analysis) in the second embodiment. FIG. 4 is a characteristic diagram showing the result of absorbance measurement (absorbance analysis) in the second embodiment. FIG. 5 is a process diagram for explaining a method for measuring a volatile organic substance in Embodiment 4 of the present invention. FIG. 6 is a characteristic diagram showing an RGB analysis result of color image data obtained by imaging the first sensing element in the fourth embodiment with a color imaging device. FIG. 7 is a characteristic diagram showing an RGB analysis result of color image data obtained by imaging the second sensing element in the fourth embodiment with a color imaging device.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[Embodiment 1]
First, Embodiment 1 of the present invention will be described. First, as shown in FIG. 1A, a detection solution 101 made of an aqueous solution in which a Schiff reagent and an acid are dissolved is prepared. For example, the detection solution 101 can be prepared by dissolving 5.0 ml of a Schiff reagent prepared from basic fuchsin and 1 ml of phosphoric acid in water to make the total amount 11 ml. This is the case where the acid described above is phosphoric acid.

  Alternatively, a detection solution in which 5.0 ml of Schiff reagent and 1 ml of concentrated sulfuric acid are dissolved in water to make the total amount 11 ml may be used. This is the case where the acid described above is sulfuric acid.

  Here, the Schiff reagent will be described. First, 0.2 g of basic fuchsin was dissolved in 120 ml of hot water (hot water), and after cooling these, 2.0 g of anhydrous sodium sulfite and 2 ml of concentrated hydrochloric acid (for example, 12N) were added to make 200 ml with water. The above Schiff reagent may be diluted.

  Next, the prepared detection solution 101 is accommodated in a container 102 made of a material that does not react with the detection solution 101, and the detection solution 101 is exposed to air (expectation) in which a gas of a volatile organic substance to be measured exists. (First step).

  For example, as shown in FIG. 1A, the air to be measured is transported into the detection solution 101 via the transport pipe 104 by the air pump 103, and the transported air is discharged into the liquid to form a large number of bubbles. The air pump 103 is a tube pump using a silicone tube, for example. Thus, an air pump in which the path through which the air to be measured is transported is made of a material that does not adsorb the unsaturated hydrocarbon gas to be measured is suitable.

As described above, after the detection solution 101 is exposed to the air to be measured, as shown in FIG. 1B, the absorbance of the detection solution 101 contained in the container 102 is measured (second step). In the measurement of the absorbance, for example, as shown in FIG. 1B, the intensity I of the transmitted light that transmits the incident light having the light intensity I ₀ is measured from the lateral direction of the container 102, and the absorbance (= log ₁₀ (I ₀₎ is measured from these. / I)). This means that the color change of the detection solution 101 is observed by absorptiometry.

  Once the absorbance is determined in this way, qualitative analysis of the volatile organic substance (gas) contained in the air is performed based on the determined absorbance spectrum (third step). Since the absorbance spectrum has characteristics unique to volatile organic substances, the volatile organic substances can be qualified. For example, a known spectrum obtained as a result of exposing the detection solution 101 to a known volatile organic substance may be compared with a spectrum obtained by doing the above. When a spectrum that matches the known spectrum is obtained, it can be identified that the air to be measured contains volatile organic substances corresponding to the known spectrum. Further, in this embodiment, since different spectra are obtained corresponding to volatile organic substances with one type of detection solution, qualitative determination of a plurality of volatile organic substances can be performed with one type of detection solution, and more rapid measurement is possible. (Analysis) is possible.

[Embodiment 2]
Next, a second embodiment of the present invention will be described. Below, the measurement method of a volatile organic substance is demonstrated with preparation of the sensing element in this Embodiment 2. FIG.

  First, the production of the sensing element will be described. As shown in FIG. 2A, a sensing solution 201 made of an aqueous solution in which a Schiff reagent and an acid are dissolved is produced in a container 202. For example, the detection solution 201 can be prepared by dissolving 5.0 ml of a Schiff reagent prepared from basic fuchsin and 1 ml of phosphoric acid in water to make a total volume of 11 ml. This is the case where the acid described above is phosphoric acid. Alternatively, a detection solution in which 5.0 ml of Schiff reagent and 1 ml of concentrated sulfuric acid are dissolved in water to make the total amount 11 ml may be used. This is the case where the acid described above is sulfuric acid.

  Next, as shown in FIG. 1B, a porous body 203 that is porous glass having an average pore diameter of 4 nm is immersed in the detection solution 201. The porous body 203 is, for example, Vycor # 3970 manufactured by Corning. Vycor # 3970 is a porous body having a plurality of pores having an average pore diameter of 4 nm. The porous body 203 has, for example, a chip size of 8 (mm) × 8 (mm) and a thickness of 1 (mm). The porous body 203 preferably has an average pore diameter of 20 nm or less. Although the detection element 203 is plate-shaped here, it is not limited to this, and it may be formed in a fiber shape.

In the case where the porous body 203 is made of glass (borosilicate glass), the average pore diameter is set to 20 nm or less, so that in the measurement of the transmission spectrum in the visible UV wavelength region (wavelength 200 to 2000 nm), the visible light region (350 to At 800 nm), light is transmitted. However, it has been found that when the average pore diameter increases beyond 20 nm, a sharp decrease in transmittance is observed in the visible region (see Patent Document 3). Thus, the porous body should have an average pore diameter of 20 nm or less. On the other hand, in order to enable detection of gas, the average pore diameter must be larger than the molecules of the detection agent and the gas to be measured. Therefore, the lower limit of the average pore diameter is 2 nm, which is the minimum value at which the molecules of the detection agent and the measurement target gas can enter. In addition, the specific surface area of the porous body 203 in the present embodiment is 100 m ² or more per 1 g.

  The porous body 203 described above is immersed in the detection solution 201 for 24 hours, and the pores of the porous body 203 are impregnated with the detection solution. Then, the porous body 203 impregnated with the detection solution is air-dried, and as shown in FIG. The detector element 203a is manufactured by leaving it in a gas stream for 24 hours to dry.

  Accordingly, the detection element 203a is introduced with the detection agent composed of each component constituting the detection solution described above, and the detection agent is supported in the porous pores of the detection element 203a. As is well known, the porous body 203 includes a plurality of pores. These pores are through-holes connected from the opening on the surface of the porous body 203 to the inside. The detection agent contains moisture adsorbed in the pores due to the presence of humidity in the atmosphere (atmosphere) in which the detection element 203a is disposed, and forms a thin water (detection solution) film on the inner wall of the pores. It can be considered a thing.

  The term “support” refers to a state in which each substance constituting the detection solution is chemically, physically, or electrically bonded to the carrier (base material). For example, the detection solution (in the pores of the porous body) The detection agent is infiltrated, the wall surface in the hole is covered with the detection agent, and / or the detection agent is deposited on the side wall in the hole.

  According to the thus configured sensing element 203a, the state of light absorption changes as will be described later when gaseous volatile organic substances enter the hole. When the volatile organic substance (gas) enters the hole, the detection agent (detection solution) arranged in the hole reacts with the volatile organic substance that has entered. As a result of this reaction, the optical characteristics of the sensing element 203a change.

  Next, a method for measuring a volatile organic substance using the detection element 203a will be described.

First, as shown in FIG. 2D, for example, the sensing element 203a is exposed to, for example, an air 204 to be measured in which volatile organic gas exists (first step). This exposure is performed at room temperature (about 20 ° C.). Thereafter, the measured detection element 203a is taken out from the air 204 to be measured, and the absorbance in the thickness direction of the measured detection element 203a is measured to obtain the absorbance as shown in FIG. 2E (second step). . For example, the intensity I of the transmitted light that transmits the incident light having the light intensity I ₀ is measured, and the absorbance (= log ₁₀ (I ₀ / I)) is obtained from these. Thus, the absorbance can be obtained by measuring the light transmittance of the detection element 203a.

  Once the absorbance is obtained in this manner, the volatile organic substance contained in the air is qualitatively determined based on the obtained absorbance spectrum (third step). Since the absorbance spectrum has characteristics unique to volatile organic substances, the volatile organic substances can be qualified.

  The results of the above-described absorbance measurement (absorbance analysis) are shown in FIGS. The absorption with a transmitted light measurement wavelength of 350 nm or less is the absorption of the porous glass (Vycor # 3970) itself constituting the sensing element. FIG. 3 shows the result of the sensing element with the sensing solution using phosphoric acid as the acid, and FIG. 4 shows the result of the sensing element with the sensing solution using sulfuric acid as the acid. The spectrum of n-nonylaldehyde is indicated by a thin solid line, the spectrum of propionaldehyde is indicated by a thin dotted line, the spectrum of styrene is indicated by a thin one-dot chain line, and the spectrum of limonene is indicated by a thin two-dot chain line. The spectrum of α-pinene is indicated by a thick solid line, the spectrum of 2-methyl-3-buten-2-ol is indicated by a thick dotted line, and benzaldehyde is indicated by a thick dashed line.

  As shown in FIGS. 3 and 4, even when any detection solution is used, each volatile organic substance has its own spectrum, and by these differences, it is possible to qualify each volatile organic substance. It becomes. In addition, according to the present embodiment, different spectra can be obtained corresponding to volatile organic substances by using one type of detection solution. Therefore, qualitative determination of a plurality of volatile organic substances can be performed with one type of detection solution. Measurement (analysis) is possible. In the measurement of the light transmittance of the detection element 203a, the spectrum of the detection solution (detection agent) excluding the absorption of the porous glass itself can be obtained by using the porous body 203 as a target.

[Embodiment 3]
Next, a third embodiment of the present invention will be described.

  In the present embodiment, the detection solution composed of the aqueous solution in which the Schiff reagent and the acid are dissolved in the first step is exposed to the gas to be measured for a predetermined time, and the color change of the detection solution is obtained in the second step thereafter. In qualifying the volatile organic substance contained in the gas according to the obtained color change state in the third step, first, in the first step, the first step consists of an aqueous solution in which the Schiff reagent and sulfuric acid are dissolved. The 1st detection solution and the 2nd detection solution which consists of the aqueous solution which the Schiff reagent and phosphoric acid melt | dissolved are exposed to the gas to be measured for the set time.

  Next, in the second step, the color change of the first detection solution and the color change of the second detection solution are visually observed. Thereafter, in the third step, formaldehyde, propionaldehyde, n-nonylaldehyde, benzaldehyde, styrene, isoprene, α contained in the gas due to the color change of the first detection solution and the color change of the second detection solution. -A volatile organic material selected from pinene, limonene and 2-methyl-3-buten-2-ol was qualitatively performed.

  Hereinafter, with respect to the method for measuring a volatile organic substance in the present embodiment, each detection element is used in the case of using two detection elements in which each detection solution is disposed (impregnated) in the pores of a transparent porous body made of glass. This will be described together with the production.

  First, production of the sensing element A using the first sensing solution will be described. First, 0.2 g of basic fuchsin was dissolved in 120 ml of hot water (hot water), and after cooling these, 2.0 g of anhydrous sodium sulfite and 2 ml of concentrated hydrochloric acid (for example, 12N) were added to make 200 ml with water. Make diluted Schiff reagent. Next, 5.0 ml of the manufactured Schiff reagent and 1 ml of concentrated sulfuric acid are dissolved in water to prepare a first detection solution having a total amount of 11 ml. Next, a porous body made of porous glass is immersed in the prepared first detection solution, and this is air-dried to form the detection element A. These sensing elements are manufactured in the same manner as in the second embodiment described above.

  Next, production of the sensing element B using the second sensing solution will be described. A second detection solution having a total amount of 11 ml is prepared by dissolving 5.0 ml of the Schiff reagent prepared as described above and 1 ml of phosphoric acid in water. Next, a porous body made of porous glass is immersed in the prepared second detection solution, and this is air-dried to form a detection element B. The production of these sensing elements is the same as in the second embodiment described above.

  Next, the produced sensing element A and sensing element B are exposed to an atmosphere (air) containing 2000 ppm of volatile organic matter (gas) for 8 hours. Volatile organic substances are benzene, toluene, xylene, methanol, 2-butanone, acetic acid, ethyl acetate, formaldehyde, propionaldehyde, n-nonylaldehyde, benzaldehyde, styrene, isoprene, α-pinene, limonene, and 2-methyl-3. -Buten-2-ol.

  Here, the following Table 1 shows the initial color of the detection element A and detection element B for each volatile organic substance, the color after exposure to the volatile organic substance, and whether there is a change in color after exposure to the initial stage. Show. The color is the result of visual observation.

  As is clear from Table 1, benzene, toluene, xylene, methanol, 2-butanone, acetic acid, ethyl acetate, and isoprene have no color change. For this reason, these are volatile organic substances that cannot be measured by visual judgment using the above-described sensing element.

  On the other hand, in formaldehyde, propionaldehyde, n-nonylaldehyde, benzaldehyde, styrene, α-pinene, limonene, and 2-methyl-3-buten-2-ol, a color change is visually observed. In this, first, benzaldehyde and 2-methyl-3-buten-2-ol have the same color change (coloration) in the sensing element A and the sensing element B. Benzaldehyde has turned brown in both sensing elements, and 2-methyl-3-buten-2-ol has turned green in both sensing elements.

  Next, propionaldehyde and n-nonylaldehyde undergo different color changes between the sensing element A and the sensing element B. However, both of them change to blue-violet in the detection element A and change to blue in the detection element B.

  Next, formaldehyde changes to purple in the detection element A, and changes to blue-violet in the detection element B.

  Next, styrene changes to blue in the detection element A, and changes to green in the detection element B.

  Next, isoprene turns brown in the sensing element A, and turns yellow in the sensing element B.

  Next, α-pinene changes to black brown in the detection element A, and changes to yellow in the detection element B.

  Next, limonene changes to a group blue color in the detection element A and changes to brown in the detection element B.

  As apparent from the above, for formaldehyde, propionaldehyde, n-nonylaldehyde, benzaldehyde, styrene, isoprene, α-pinene, limonene, and 2-methyl-3-buten-2-ol, sensing element A Since the color change is different between the detection element B and the detection element B, these substances can be distinguished and qualitatively possible. However, since propionaldehyde and n-nonyl aldehyde cannot be distinguished by visual judgment, they cannot be qualified when they coexist.

[Embodiment 4]
Next, a fourth embodiment of the present invention will be described. In the present embodiment, a volatile organic substance is measured using the detection element in the second embodiment described above.

  First, in the same manner as in Embodiment 2 described above, a detection element is prepared in which a detection solution made of an aqueous solution in which a Schiff reagent and an acid are dissolved is arranged in a hole of a transparent porous body made of glass.

  Next, as shown in FIG. 2D, for example, the sensing element 203a is exposed to, for example, an air 204 to be measured in which volatile organic gas exists (first step). This exposure is performed at room temperature (about 20 ° C.), for example. Thereafter, the measured detection element 203a is taken out from the air 204 to be measured, and the measured detection element 203a is imaged by the color imaging device 501 as shown in FIG. The color imaging device 501 includes, for example, a pixel having a so-called color filter and a solid-state imaging device that converts light transmitted through the color filter into an electrical signal, and a plurality of such pixels are arranged two-dimensionally. It is configured.

  RGB analysis result comprising density values (signal intensities) of RGB colors constituting the color image data from the color image data (for example, RGB bitmap image) of the detection element 203a obtained by the above-described imaging of the color imaging device 501. (Second step). The volatile organic substance contained in the gas is qualitatively determined according to the RGB analysis result thus obtained (third step). Similar to the absorbance spectrum, the RGB analysis result has characteristics unique to the volatile organic substance, so that the volatile organic substance can be qualified.

  This will be described in more detail below. First, the detection element will be described. For example, 0.2 g of basic fuchsin is dissolved in 120 ml of hot water, cooled, and then dissolved by adding 2 g of anhydrous sodium sulfite and 2 ml of concentrated hydrochloric acid to produce a colorless Schiff reagent. Water is added to 5 ml of this Schiff reagent and 1 ml of concentrated sulfuric acid to make 11 ml, thereby preparing a first detection solution. This first detection solution is impregnated with porous glass (Corning Vycor porous glass # 3970) having a pore diameter of 4 nm (24 hours) and dried in dry nitrogen for 24 hours to obtain a first detection element.

  Further, 0.2 g of basic fuchsin is dissolved in 120 ml of hot water, cooled, and then dissolved by adding 2 g of anhydrous sodium sulfite and 2 ml of concentrated hydrochloric acid to produce a colorless Schiff reagent. Water is added to 5 ml of this Schiff reagent and 1 ml of phosphoric acid to make 11 ml, thereby preparing a second detection solution. This second detection solution is impregnated with porous glass (Corning Vycor porous glass # 3970) having a pore diameter of 4 nm (24 hours) and dried in dry nitrogen for 24 hours to obtain a second detection element.

  Next, the first sensing element and the second sensing element described above are exposed to the air to be measured in the presence of volatile organic gas for 8 hours. Volatile organic substances are benzene, toluene, xylene, methanol, 2-butanone, acetic acid, ethyl acetate, formaldehyde, propionaldehyde, n-nonylaldehyde, benzaldehyde, styrene, isoprene, α-pinene, limonene, 2-methyl-3- Buten-2-ol.

  Next, the results of the above measurement will be described. First, the results of visual observation of the color change of each detection element will be described. First, no color change is visually observed for benzene, toluene, xylene, methanol, 2-butanone, acetic acid, ethyl acetate, and isoprene. On the other hand, formaldehyde, propionaldehyde, n-nonylaldehyde, benzaldehyde, styrene, α-pinene, limonene, and 2-methyl-3-buten-2-ol are visually observed to change in color.

  In addition, propionaldehyde and n-nonylaldehyde are observed to have the same color change in the first sensing element and the second sensing element, but a color change different from that of formaldehyde is observed and can be distinguished (qualitatively). Benzaldehyde has a color change different from that of formaldehyde, propionaldehyde, and n-nonylaldehyde, and can be distinguished (qualitative).

  Further, in the second detection element, since styrene shows blue and limonene shows group blue, it is not easy to distinguish colors. On the other hand, in the first sensing element, styrene shows green and limonene shows brown, so that the color can be distinguished. Therefore, styrene and limonene can be clearly distinguished (qualitatively) by combining two sensing elements.

  By the way, in the analysis by visual observation described above, the subjectivity of the observer is entered. In order to remove this individual difference due to the subjective, each detection element is exposed to the air to be measured, and then captured by a color imaging device to obtain color image data, and RGB analysis is performed on the acquired color image data. FIG. 6 is a characteristic diagram showing RGB analysis results of color image data obtained by imaging the first sensing element with a color imaging device. FIG. 7 is a characteristic diagram showing RGB analysis results of color image data obtained by imaging the second sensing element with a color imaging device. In both cases, the B value is normalized as 1.

  The color imaging device to be used is “DimageXg” manufactured by Konica Minolta. Further, each sensing element is imaged under illumination of “king digital copy stand LV-5” (Asanuma Shokai Co., Ltd.) as a light source. The RGB analysis is performed in a 5 × 5 (mm) region at the center of each detection element in the color image data obtained by imaging.

  Volatile organic substances contained in the air to be measured are formaldehyde, propionaldehyde, n-nonylaldehyde, benzaldehyde, styrene, α-pinene, limonene, and 2-methyl-3-buten-2-ol. . 6 and 7, “before exposure” is the RGB analysis result of the color image data obtained by imaging with the color imaging device before being exposed to the air to be measured.

  Here, as shown in FIG. 6, in the RGB analysis result in the measurement using the first sensing element, propionaldehyde and n-nonylaldehyde show similar patterns. In the case of the first sensing element, benzaldehyde, α-pinene, and limonene exhibit a similar pattern. In the case of the first sensing element, styrene and 2-methyl-3-buten-2-ol show similar patterns. In contrast, formaldehyde shows a unique pattern. Therefore, the RGB analysis in the measurement using the first sensing element shows that qualitative formaldehyde can be performed.

  On the other hand, the RGB analysis results in the measurement using the second sensing element all show a unique pattern, indicating that each volatile organic substance targeted for measurement can be qualified. Thus, it is clear that the detection substance can be identified (qualitatively) more objectively and accurately by acquiring the color image of the detection element and performing the RGB analysis processing.

  The present invention is not limited to the embodiment described above. In the present invention, the inventors have found that a detection solution combining a Schiff reagent and an acid has a different coloration state depending on a volatile organic substance (gas), and a detection solution combining a Schiff reagent and an acid is This is a result of finding out that the colored state is different even when exposed (reacted) to the same volatile organic substance (gas) due to the difference in the acid to be combined. Therefore, it is obvious that many variations can be implemented by those having ordinary knowledge in the art within the technical idea of the present invention described above.

  For example, although the case where sulfuric acid and phosphoric acid are used as the acid to be added to the Schiff reagent has been described, the present invention is not limited to this, and other acids such as formic acid, oxalic acid, hydrochloric acid and the like can also be used. . Since hydrochloric acid has a high vapor pressure, it easily volatilizes and is not suitable for long-term storage.

  In the above description, the case where two types of detection solutions are used, that is, a detection solution combining a Schiff reagent and sulfuric acid and a detection solution combining a Schiff reagent and phosphoric acid, is not limited to this. Three or more types of detection solutions in which a Schiff reagent and a different acid are combined may be used to qualify the volatile organic substance by changing the color of the obtained three or more types of detection solutions. For example, in the third detection solution other than the detection solution combining Schiff reagent and sulfuric acid and the detection solution combining Schiff reagent and phosphoric acid, if the coloration due to the reaction with propionaldehyde and n-nonylaldehyde can be visually identified, These qualities (identification) are also possible.

  In the above description, the Schiff reagent is prepared using concentrated hydrochloric acid. However, the present invention is not limited to this, and the Schiff reagent may be prepared from fuchsin by a well-known method. For example, desulfurization may be performed by adding sulfurous acid to an aqueous solution in which basic fuchsin (fuchsin chlorine salt) is dissolved, and adding an aqueous solution saturated with sulfur dioxide thereto.

  101 ... Detection solution, 102 ... Container, 103 ... Air pump, 104 ... Transport pipe.

Claims (7)

A first step of exposing a detection solution comprising an aqueous solution in which a Schiff reagent and an acid are dissolved to a gas to be measured;
After the first step, a second step for determining the absorbance of the detection solution;
Selected from propionaldehyde, n-nonylaldehyde, benzaldehyde, styrene, α-pinene, limonene, and 2-methyl-3-buten-2-ol contained in the gas according to the state of the obtained absorbance spectrum And a third step of qualitating the volatile organic substance formed. A method for measuring a volatile organic substance. In the measuring method of the volatile organic substance of Claim 1,
In the first step, the detection element in which the detection solution is arranged in the hole of a transparent porous body made of glass is exposed to the gas,
In the second step, the absorbance is obtained by measuring the light transmittance of the sensing element. A method for measuring a volatile organic substance. In the measuring method of the volatile organic substance of Claim 1 or 2,
In the third step, qualitative analysis is performed by comparing the spectrum with a known spectrum obtained for a known volatile organic substance. A method for measuring a volatile organic substance. A first step of exposing a first detection solution consisting of an aqueous solution in which a Schiff reagent and sulfuric acid are dissolved, and a second detection solution consisting of an aqueous solution in which the Schiff reagent and phosphoric acid are dissolved;
A second step of visually observing the color change of the first detection solution and the color change of the second detection solution;
The color change of the color change and the second detector solution of the first detection solution, the contained in a gas, formaldehyde, base lens aldehydes, styrene, alpha - pinene, limonene and 2-methyl-3- A volatile organic substance measuring method comprising at least a third step of qualifying a volatile organic substance selected from buten-2-ol. In the measuring method of the volatile organic substance of Claim 4,
In the first step, the first sensing element and the second sensing element in which the first sensing solution and the second sensing solution are arranged in the pores of a transparent porous body made of glass are exposed to the gas,
In the second step, the color change of the first detection solution and the color change of the second detection solution are observed by visually observing the color change of the first detection device and the second detection device. A method for measuring volatile organic substances characterized by A first step in which a detection solution made of an aqueous solution in which a Schiff reagent and an acid are dissolved is exposed to a gas to be measured in a detection element disposed in a hole of a transparent porous body made of glass;
After the first step, an RGB analysis result comprising density values of RGB colors constituting the color image data is obtained from the color image data of the detection element obtained by imaging the detection element with a color imaging device. Two steps,
According to the RGB analysis results obtained, among the formaldehyde, propionaldehyde, n-nonylaldehyde, benzaldehyde, styrene, α-pinene, limonene, and 2-methyl-3-buten-2-ol contained in the gas. And a third step of qualifying the selected volatile organic substance. A method for measuring a volatile organic substance. In the measuring method of the volatile organic substance of Claim 6,
In the first step, a first sensing element made of an aqueous solution in which a Schiff reagent and sulfuric acid are dissolved is dissolved in a first sensing element arranged in a hole of a transparent porous body made of glass, and the Schiff reagent and phosphoric acid are dissolved. Exposing the second sensing element, which is disposed in the hole of the transparent porous body made of glass, to the gas to be measured.
In the second step, a first RGB analysis result is obtained from the first sensing element, a second RGB analysis result is obtained from the second sensing element,
In the third step, the first RGB analysis result and the second RGB analysis result are compared to qualify the volatile substance contained in the gas. A method for measuring a volatile organic substance.

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