JP2006322922A - Chromium detecting reagent - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To allow use for confirming easily that a destruction rubbish, in particular, a destruction timber is not CCA-contaminated with use of an antiseptic, a termite-proof agent or the like, by brush coating or spraying in a field, when recycling the destruction rubbish, in particular, the destruction timber. <P>SOLUTION: Diphenylcarbazide is dissolved in a solvent containing acetone and ethanol. Coloring is intensified when an organic acid other than acetic acid is added. Storability is ensured without losing coloring performance, by adding the organic acid, and by adding about 5% of vitamins to 100 pts.wt as total of the acetone and ethanol, in a solution dissolved with the diphenylcarbazide of favorable amount. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a reagent for detecting heavy metals harmful to the human body adhering to the surface of construction materials such as waste wood, in particular, the solubility of diphenylcarbazide that can detect Cr by a color development reaction, and the color developability, and The present invention relates to a reagent for detecting chromium, which is made commercially available with improved stability and storage stability.

  In recent years, the Construction Recycling Law (Act on the Recycling of Materials Related to Construction Work) has been enforced, requiring the separation and dismantling and recycling of construction material waste. Examples of construction material waste include stone, concrete, asphalt, plastics, and wood, but there is a problem in recycling waste wood. In other words, waste wood is harmful because there are bundles and beams laid under the floor in addition to plate materials and pillars used in houses, and antiseptics and ant protection agents are sprayed on them. This is because heavy metals such as valent chromium and copper may be contained.

  Because of these problems, there is an idea of giving up dismantling and making wood chips for power generation. However, waste wood contains high-grade wood such as high-strength wood and moss that are over 100 years old, and these are definitely places where we want to reuse them.

  Therefore, we dismantle and separate waste wood and detect the attachment of chromium, copper, and arsenic compound chemicals (hereinafter abbreviated as CCA chemicals) for the main waste wood. It is considered to be used.

  As a method for determining the presence or absence of a CCA drug, the framework wall construction method lumber standard of JAS (Japan Agricultural Standard) is established. In this method, diphenylcarbazide is dissolved in isopropyl alcohol, and water is added thereto to form a detection agent, which is applied to the surface of the product to be inspected, and the presence or absence of CCA is known by a color reaction. Similarly, in JIS (Japanese Industrial Standard) K0102, a method for dissolving diphenylcarbazide in water and acetone and administering it to water for water quality inspection is shown. Can be detected. However, although these reagents can detect CCA drugs, they can only be used in a laboratory and cannot be used in the field. This is because the preservability is extremely poor and it must be used after the preparation, for example, within the same day. The necessity of determining whether or not it can be recycled is generated at the site of dismantling, and it is impossible to bring a separate product having a length of 3 to 4 m to the test site.

  The optical method disclosed in Japanese Patent Laid-Open No. 2003-270137 is intended to detect Cu, Cr and As by irradiating light on the surface of waste wood, measuring the reflected light through a filter and measuring the reflection intensity. is there. This method is a highly reliable method because it can detect chromium, copper, and arsenic simultaneously using near-infrared spectrophotometry, but the apparatus is expensive and difficult to purchase easily.

  Non-patent document 1 published by the Hokkaido Prefectural Forest Products Experiment Station introduces a method for detecting CCA wood using a detection reagent containing chrome azurol S. Chromazurol S is a copper detection reagent, and can detect wood containing CCA by detecting copper. However, since copper is also contained in current copper-based antiseptic / anticides other than CCA, this method is insufficient as a reagent for detecting CCA.

  On the other hand, as a method for detecting arsenic, it has been introduced in JISK0102, but it requires complicated operations and cannot be used as a simple reagent. As a method for detecting arsenic, a molybdenum oxide blue colorimetric method is known. This is a method that utilizes the fact that the molybdate and the arsenic compound react and develop a blue color, but the molybdate is also used for the detection of phosphate and silica. Therefore, this method cannot be applied to a biological material that contains a large amount of phosphorus and that touches rocks and soils mainly composed of silica. In addition to CCA, a PF agent is known as an antiseptic / preservative for wood containing both chromium and arsenic, and both CCA and PF agent containing arsenic can be detected by detecting chromium.

  In order to solve these problems, Japanese Patent Application Laid-Open No. 2004-257871 (method for determining the content of chemicals in waste wood) has been introduced. This is a method using a coloring reagent, which is applied to the surface of waste wood and knows the content of the CCA drug by its color development. Has been. However, since this coloring reagent uses a large amount of acetic acid as a solvent, it has a peculiar acetic acid odor, which causes problems in manufacturing hygiene management and a significant discomfort for workers using the reagent. There was a problem. Further, the dissolution time of diphenylcarbazide at the time of producing the reagent takes about 5 minutes, and the production takes time. Furthermore, the dissolving power is not sufficient, the amount of precipitation is large, the quality deteriorates early, and many problems remain in practical use.

Since diphenylcarbazide is very unstable, it is oxidized by dissolved oxygen dissolved in the solvent, and it changes to light pink or dark red within a few hours to several days after the preparation of the reagent. Even if stored in a cool dark place such as a refrigerator, the storage period is limited to about one week. For this reason, it is necessary for the user to prepare the reagent at the site where the user inspects the CCA waste wood, and there is still a problem in practicality from this point.
Japanese Patent Laid-Open No. 2003-270137, page 1, FIG. JP 2004-257871 A, page 1 Guide for separating CCA-treated timber in house demolition work, November 2004, Hokkaido Forestry Experiment Station

  In view of the above-mentioned background art, the present invention can be supplied to the field by filling the container by increasing the storage stability in addition to improving the solubility and color development degree of diphenylcarbazide. It aims at providing the reagent for chromium detection which can be easily used by coating or spray specification.

  The chromium detection reagent of the present invention capable of solving the above problems is characterized in that diphenylcarbazide is first dissolved in a solvent containing acetone and ethanol.

  According to the diligent research of the present inventor, although diphenylcarbazide specified in JAS and JIS is soluble in various organic solvents, there is a difference in solubility depending on the type of solvent, and it is not used in isopropanol specified in JAS and acetone specified in JIS. It is enough. Further, the combination with ethanol and acetic acid described in Patent Document 2 is insufficient. Therefore, as a result of a compounding test aiming at a synergistic effect by a combination of various solvents having relatively little harmfulness, it was found that the combination of acetone and ethanol has a maximum dissolution effect. By dissolving diphenylcarbazide in a combined solvent of acetone and ethanol, the dissolution rate and the amount of dissolution can be increased by 2 times and 3 times compared to the conventional example, thereby preventing precipitation after blending.

  Secondly, the chromium detection reagent of the present invention dissolves diphenylcarbazide in a solvent containing acetone or ethanol and, as a color enhancer, citric acid, malic acid, glycolic acid, malonic acid or tartaric acid. One or more organic acids selected from the above are included.

  Although acetic acid disclosed in Patent Document 2 acts as another color-enhancing agent that improves solubility, when it is used in a large amount instead of a solvent, it has a strong odor and causes problems in practical use. In order to eliminate this difficulty, the present inventor decided to leave diphenylcarbazide dissolved in acetone and ethanol as the first invention, and let the organic acid be responsible only for the color enhancement effect. In addition, instead of acetic acid having a bad odor effect, it was decided to select from citric acid, malic acid, glycolic acid, malonic acid, and tartaric acid. Unlike acetic acid, these organic acids are solid at room temperature and do not serve as solvents in the first place. This has led to the completion of a chromium detection reagent that can be visually recognized in about a few minutes without bad odor and can be stored and maintained.

  Third, the chromium detection reagent of the present invention dissolves diphenylcarbazide in water and an organic solvent, adds an organic acid as a color-enhancing agent, and further adds L (+)-ascorbic acid (vitamin as an antioxidant). C)), and α (±) -tocopherol (vitamin E), and / or esosorbic acid which is a structural isomer of L (+)-ascorbic acid. As vitamins C, it is possible to add juices such as citrus fruits such as lemon and mandarin oranges, other fruits or vegetables, etc., not just pure vitamin C.

  By including vitamins, oxidation is prevented and the storage stability is significantly improved. If this is not included, the solution of diphenylcarbazide becomes colored and unusable after a few days at most. On the other hand, when a small amount of vitamins are added, there is no change even after 3 months or more. However, if too much vitamins are added, the color developability of diphenylcarbazide is inhibited, so the usable range is 1 to 200% by weight with respect to 100% by weight of diphenylcarbazide. Preferably it is 5 to 30% by weight, optimally 10 to 20% by weight. Acetic acid can be included as an organic acid, but in this case, it should be limited to about 10 parts by weight with respect to 1 part by weight of diphenylcarbazide as an amount that does not cause malodor.

  By dissolving diphenylcarbazide in a solvent mainly composed of acetone and ethanol, the solubility (dissolution rate and non-precipitation degree) of diphenylcarbazide can be remarkably increased.

  Dissolve diphenylcarbazide in a solvent containing acetone or ethanol, and include at least one organic acid selected from citric acid, malic acid, glycolic acid, malonic acid or tartaric acid as a color enhancer In this case, a chromium detection reagent with improved color developability can be produced in a sanitary manner without causing a bad odor problem, and there is no adverse effect on field use.

  According to the chromium detection reagent which dissolves diphenylcarbazide in water and an organic solvent, adds an organic acid as a color enhancer, and further contains vitamins as an antioxidant, a high degree of reaction can be achieved in a few minutes. Since it can realize color development and can be stored for a long time, it can be made into a product that can be used in the field by brushing or spraying.

[Example 1]
Examples according to the first invention are shown in Table 1 and FIG. As shown in Table 1, 0.5 g of diphenylcarbazide was dissolved in a solvent of 10 ml of acetone and 15 ml of ethanol. In Comparative Example 1, 0.25 g of diphenylcarbazide as dissolved in JAS is dissolved in 25 ml of isopropanol. Comparative Example 2 is obtained by dissolving 0.5 g of diphenylcarbazide in 25 ml of acetone as defined in JIS. Comparative Example 3 is based on Patent Document 2, in which 0.25 g of diphenylcarbazide is dissolved in a mixed solution of 12.5 ml of ethanol and 12.5 ml of acetic acid.

  As shown in Table 1 as dissolution time (seconds), Example 1 of the present invention has a dissolution time of 60 seconds at a low temperature (18 ° C.), which is easier and faster than Comparative Examples 1, 2, and 3. Is dissolved. In the case of the JAS standard shown in Comparative Example 1, 0.25 g of diphenylcarbazide was added to 25 ml of isopropanol and stirred. As a result, it did not dissolve even after 10 minutes at room temperature, and was again heated to 64 ° C. in hot water for 222 seconds. It finally dissolved. In the case of the JIS standard shown in Comparative Example 2, 0.5 g of diphenylcarbazide was added to 25 ml of acetone and stirred, resulting in dissolution at room temperature in 75 seconds. When the thing of patent document 2 was confirmed in our company, as a result of adding and stirring 0.25 g of diphenylcarbazide to the solvent which mixed 12.5 ml of acetic acid and 12.5 ml ethanol, it melt | dissolved in 83 seconds. From these results, the effectiveness of the present invention is understood. In addition, as shown in Table 1, in the present invention, the amount of dissolved diphenylcarbazide is higher than the unit solvent amount, and the synergistic effect of acetone and ethanol is significant. Fast dissolution rate, high solubility and low precipitation.

[Example 2]
Examples for the second invention are shown in Table 2 and FIG. Example 2 in Table 2 is obtained by adding glycolic acid to the formulation according to Example 1, and dissolving 1.5 g of diphenylcarbazide and 5 g of glycolic acid in 30 ml of acetone, 45 ml of ethanol and 25 ml of water. It is. In Comparative Examples 4, 5, and 6, 50 ml of water was added to twice the amount of Comparative Examples 1, 2, and 3, respectively. The solubility is the same as that shown in Example 1 above.

  FIG. 2 shows the result of measuring absorbance (color development) at a wavelength of 540 nm with a spectrophotometer obtained by adding 0.3 ml of each reagent to 3 ml of a separately prepared 2 mg-Cr / L hexavalent chromium solution. . The color of Example 2 is higher than that of Comparative Examples 5 and 6. That is, a value of 1.4 is shown in 60 seconds. Although substantially equivalent to Comparative Example 4, Example 1 is higher.

  It can be seen that the reagent of the present invention has the highest degree of color development and the fast color development rate. This means that when applied to the wood surface, the result can be known in about a few minutes, and it is understood that the practicality is high.

Example 3
Examples of the third invention are shown in Table 3 and FIG. In the formulation of Table 3, the glycolic acid of the formulation of Example 2 shown in Table 2 is malic acid, and 0.2 g of vitamin C as an antioxidant is added thereto. Comparative examples 7, 8, and 9 are obtained by intentionally adding 0.2 g of vitamin C to the comparative examples 4, 5, and 6 shown above.

  As shown in Table 3, with respect to the solubility, those of Example 3 and Comparative Example 9 have no problem, but those of Comparative Example 7 were remarkably precipitated, and about half of the dissolved amount was precipitated. In Example 8, about 1/3 to half of the dissolved amount was precipitated.

  FIG. 3 shows the results of the color development test of Example 3 and Comparative Examples 7, 8, and 9. As shown in the figure, the color development degree is remarkably reduced except for Example 3 of the present invention, but it can be seen that the color development degree of the present invention is slight. This shows that the reagent of the present invention is superior to existing reagents. That is, when vitamin C is added, the degree of color development generally decreases, but it can be seen that the degree of color development of the present invention to which the solubility is increased and an organic acid is added is slight.

Example 4
Another embodiment for the third invention is shown in Table 4 and FIG. In Example 4, 0.2 g of vitamin C and 5 g of citric acid were added to 1.0 g of diphenylcarbazide, and this was dissolved in 75 ml of ethanol and 25 ml of water. This is the same as that of Comparative Examples 5 and 6 shown in Comparative Examples 5 and 6. The solubility of Example 4 was as good as that of Example 3.

  FIG. 4 shows the results obtained by putting each reagent in a cell and measuring the absorbance (degradation degree) at a wavelength of 540 nm with a spectrophotometer. As can be seen from the figure, the effect of vitamin C is insignificant, and Example 4 has no change and no precipitation after 84 days. The present inventor has confirmed that the absorbance when the coloration can be confirmed visually under these experimental conditions is about 0.03. The reagent added with vitamin C of the present invention maintains a deterioration level of around 0.01 even after 84 days (= 12 weeks = about 3 months). On the other hand, in the case where vitamin C was not added, the absorbance exceeded 0.03 in 2 to 3 days, and it was confirmed that the product was rapidly deteriorated. In contrast to the conventional JAS standard, JIS standard, and Patent Document 2 with vitamin C added, the color developability is remarkably impaired, whereas the reagent of the present invention has much impaired color developability even when vitamin C is added. Not.

  Thus, according to the present invention, the conventional reagent is deteriorated in a few days and has no storage stability, and an appropriate solvent and an organic acid are added and mixed, and an appropriate amount of an antioxidant is added. Therefore, it enables long-term storage for about 3 months or more and opens the way to practical use.

  The reagent of the present invention is highly superior to existing reagents in terms of solubility, color development rate and color development property, and storage stability of diphenylcarbazide. The practicality has become much higher.

  The reagent for detecting chromium according to the present invention is filled in a paint container or a spray can, and provided to the construction, dismantling, etc. site, for example. It can be done quickly and inexpensively. It can be used easily and hygienically without acetic acid odor.

  For waste wood that could not detect chromium, it is recommended that a sticker that has been detected that it does not detect chromium and does not contain at least hexavalent chromium be applied. This opens the way for safe use of useful resources. It can also be used for water quality inspection as a reagent conforming to JIS.

  The present invention is not limited to the above-described embodiment, and can be modified and implemented without departing from the gist of the present invention, and can be implemented in various modes. The application field is not limited to waste wood, but can be widely applied to other waste materials and other materials.

The graph which shows the melt | dissolution performance of this invention (1st invention), a horizontal axis shows time (second), and a vertical axis | shaft shows the amount of dissolution (g). The graph which shows the coloring performance of this invention (2nd invention), a horizontal axis shows time (second), and a vertical axis | shaft shows a coloring degree. In the graph showing the non-reducing performance of the degree of color development of the present invention (third invention), the horizontal axis represents time (seconds) and the vertical axis represents the degree of color development. It is a graph which shows the preservation | save performance of this invention (3rd invention), a horizontal axis shows time (days), and a vertical axis | shaft shows the degree of deterioration which observes coloring degree.

Claims (3)

A reagent for detecting chromium, wherein diphenylcarbazide is dissolved in a solvent containing acetone and ethanol.   In addition to dissolving diphenylcarbazide in a solvent containing acetone or ethanol, the coloring enhancer includes one or more organic acids selected from citric acid, malic acid, glycolic acid, malonic acid or tartaric acid. A reagent for detecting chromium. In addition to dissolving diphenylcarbazide in water and an organic solvent, an organic acid is added as a color enhancer, and L (+)-ascorbic acid, L (+)-sodium ascorbate, L (+)- One or more vitamins selected from ascorbic acid 2-glucoside, L (+)-ascorbic acid stearate, L (+)-ascorbyl palmitate, α (±) -tocopherol, and erythorbic acid, erythorbine A chromium detection reagent comprising one or more compounds from a compound group containing sodium acid.

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