JP7581887B2 - Kit for determining concentration and method for determining concentration - Google Patents

Description

The present disclosure relates to a kit for measuring concentration and a method for measuring concentration.

Concrete structures can deteriorate due to various factors. For example, chloride ions can penetrate into concrete and destroy the passive coating of the reinforcing steel inside. Therefore, in order to maintain the concrete structure in a better condition, the concentration of certain components in the concrete can be measured. For example, Patent Document 1 discloses a method for measuring the chloride ion concentration in concrete. In this method, a powdered sample is taken from hardened concrete, and the chloride ions are dissolved in heated distilled water for a certain period of time. The chloride ion concentration of the supernatant water is measured by coulometric titration.

JP 2011-158437 A

In the method of Patent Document 1, it is necessary to prepare a solution containing concrete prior to measurement. Preparing such a solution at a maintenance site can be a burden for workers.

In consideration of the above-mentioned problems, the present disclosure aims to provide a kit for measuring concentration and a method for measuring concentration that can reduce the burden on operators by eliminating the need to prepare a solution containing a sample in advance.

One aspect of the present disclosure is a kit for measuring a concentration, comprising: a set of liquid reagents of different concentrations; a set of integrated sealed containers including a plurality of pockets for containing the set of liquid reagents; and a measuring member including a plurality of through holes arranged opposite the plurality of pockets and each having a predetermined volume .

The kit may further include a cover for covering the pockets and the through holes.

The pockets may contain the same amount of reagent, and the through-holes may have the same capacity.

Each container may have markings indicating the concentration detectable by the reagent in that container.

The set of liquid reagents may be a silver nitrate solution.

Another aspect of the present disclosure is a method for measuring concentration, comprising the steps of: preparing a set of integrated sealed containers including a plurality of pockets containing a plurality of liquid reagents of different concentrations; preparing a powdered sample; adding a predetermined amount of the powdered sample to each of the plurality of liquid reagents using a metering member including a plurality of through-holes, each having a predetermined volume , the plurality of through-holes being positioned opposite the plurality of pockets, and the powdered sample being added to each of the plurality of liquid reagents through the plurality of through -holes; and measuring the concentration of a specific component in the powdered sample based on the change in the plurality of liquid reagents.

This disclosure makes it possible to reduce the burden on operators by eliminating the need to prepare a solution containing a sample in advance.

FIG. 1 is a schematic perspective view showing a kit according to an embodiment. FIG. 2 is a schematic exploded perspective view of the kit of FIG. FIG. 3 is a cross-sectional view taken along the line III-III in FIG. FIG. 4 is a schematic perspective view showing the removal of the sealing member from the container. FIG. 5 is a schematic plan view showing a color-changing reagent. FIG. 6 is a flow chart illustrating a method according to an embodiment.

The embodiments of the present disclosure will be described in detail below with reference to the attached drawings. The dimensions, materials, and specific numerical values shown in the embodiments are merely examples for ease of understanding, and do not limit the present disclosure unless otherwise specified. In this specification and drawings, elements having substantially the same functions and configurations are designated by the same reference numerals to avoid duplicated explanations, and elements not directly related to the present disclosure are not illustrated.

[Kit 100]
1 is a schematic perspective view showing a kit 100 according to an embodiment. The kit for concentration measurement (which may also be simply referred to as a "kit" in the present disclosure) 100 is used to measure the concentration of a specific component in a powdered sample S. For example, in this embodiment, the kit 100 is used to measure the concentration of chloride ions in powdered concrete. The kit 100 includes a pack 1, a measuring member 2, and a lid 3.

Figure 2 is a schematic exploded perspective view showing the kit 100 of Figure 1. The pack 1 contains a liquid reagent L capable of detecting a specific component. In this embodiment, the reagent L is, for example, a silver nitrate solution (described in detail below). The pack 1 has a plate 10 and a sealing member 11.

Figure 3 is a cross-sectional view taken along the line III-III in Figure 1. Note that the sealing member 11 is not shown in Figure 3. The plate 10 includes a set of containers 12 (five containers 12 in this embodiment). In other words, in this embodiment, the set of containers 12 is formed as an integrated plate 10. The number of containers 12 is not limited to five, and can be two or more. The plate 10 has, for example, a rectangular shape. The shape of the plate 10 is not limited to this, and can be any shape including a plurality of pockets 13 (described below).

Each container 12 includes a pocket 13 on its upper surface. The multiple pockets 13 contain multiple liquid reagents L of different concentrations (details will be described later). The multiple pockets 13 are arranged in a line along the longitudinal direction of the rectangular plate 10. The multiple pockets 13 are arranged at equal intervals. The arrangement of the multiple pockets 13 is not limited to this and can be any arrangement. The multiple pockets 13 have the same capacity and contain the same amount of reagent L. The cross-sectional shape of each pocket 13 is semicircular. The shape of each pocket 13 is not limited to this and can be any shape that can contain a liquid. Referring to FIG. 2, each container 12 has a mark 14 near the pocket 13. The mark 14 indicates the concentration of chloride ions detectable in the silver nitrate solution in each container 12 (details will be described later).

Figure 4 is a schematic perspective view showing the sealing member 11 being peeled off from the container 12. Note that in Figure 4 (and Figure 2), the sealing member 11 is depicted semi-transparently for better understanding, but the sealing member 11 may be opaque. Each container 12 is covered by the sealing member 11. For example, the sealing member 11 may be a film attached to the plate 10. For example, the sealing member 11 may have a size roughly similar to the upper surface of the plate 10 and cover all the pockets 13. Alternatively, the sealing member 11 may have a smaller size and may be provided separately for each container 12.

As shown in the upper diagram of FIG. 4, the sealing member 11 covers the multiple containers 12 before measurement. Therefore, it is possible to prevent the reagent L from spilling out of the containers 12 before measurement. When performing measurement, the containers 12 are opened. For example, as shown in the lower diagram of FIG. 4, the sealing member 11 may be peeled off from the plate 10. Alternatively, the sealing member 11 may be torn along each pocket 13.

Referring to FIG. 2, the measuring member 2 has, for example, a rectangular flat plate shape. For example, the upper and lower surfaces of the measuring member 2 may have approximately the same size as the upper and lower surfaces of the plate 10. The shape of the measuring member 2 is not limited thereto, and can be any shape including a plurality of through holes 21 (described below). Referring to FIG. 3, the measuring member 2 is placed on the plate 10 (i.e., on top of a set of containers 12) via the lid 3 during measurement.

The measuring member 2 includes a plurality of through holes 21. The plurality of through holes 21 are arranged opposite the plurality of pockets 13 of the set of containers 12 during measurement. The plurality of through holes 21 are arranged in a line in a linear manner along the longitudinal direction of the rectangular measuring member 2. The plurality of through holes 21 are arranged at equal intervals. The arrangement of the plurality of through holes 21 is not limited to this and can be any arrangement. Each through hole 21 is dimensioned to accommodate a specified amount of powdered sample S. The plurality of through holes 21 have the same capacity. For example, each through hole 21 includes a first portion 22 and a second portion 23. The first portion 22 is located above the second portion 23 and has a larger capacity than the second portion. Each of the first portion 22 and the second portion 23 has a cylindrical shape. The shape of each through hole 21 is not limited to this and can be any shape that can accommodate powder. Each through hole 21 may have a shape that tapers downward (not shown) to promote the powdered sample S to fall into the pocket 13 (details will be described later).

The lid 3 has, for example, a rectangular flat plate shape. For example, the upper and lower surfaces of the lid 3 may have a size equal to or larger than the upper and lower surfaces of the plate 10. The upper and lower surfaces of the lid 3 may be smaller than the upper and lower surfaces of the plate 10 as long as the multiple pockets 13 and the multiple through holes 21 can be simultaneously blocked. The shape of the lid 3 is not limited thereto, and can be any shape that simultaneously blocks the multiple pockets 13 and the multiple through holes 21. The lid 3 is placed between the plate 10 and the measuring member 2 during measurement. Each of the plate 10 (container 12), the sealing member 11, the measuring member 2, and the lid 3 can be made of a material that is resistant to acid (nitric acid) and alkali (concrete), and can be made of, for example, plastic such as polyethylene, polyvinylidene chloride, or polypropylene.

[Reagent L]
Reagent L will be described in detail below.

As described above, in this embodiment, the kit 100 measures the concentration of chloride ions in powdered concrete using a silver nitrate solution as the reagent L. In general, concrete may contain chloride ions ^Cl- and hydroxide ions ^OH- . When powdered concrete is added to the silver nitrate solution _AgNO3 , the reactions shown in the following formulas (1) and (2) occur due to the chloride ions ^Cl- and hydroxide ions ^OH- in the concrete.
AgNO ₃ +Cl ^- → AgCl+NO ₃ ^-... (1)
2AgNO ₃ +2OH ^- → Ag ₂ O+H ₂ O+2NO ₃ ^-... (2)

Silver chloride AgCl is white, and silver oxide Ag ₂ O is brown. Reaction (1) takes precedence over reaction (2). Therefore, reaction (2) does not occur until all chloride ions Cl ⁻ in the sample S are used in reaction (1). In other words, when brown silver oxide Ag ₂ O is produced, it means that all chloride ions Cl ⁻ have been used in reaction (1). Therefore, the concentration of chloride ions Cl ⁻ can be estimated based on the color change of the silver nitrate solution in the set of containers 12.

5 is a schematic plan view showing the discolored reagent L. In this embodiment, the pocket 13 of each container 12 contains 5 mL (=5×10 ⁻³ (L)) of silver nitrate solution, and 1 (mL) (=1 (cm ³ )=1×10 ⁻⁶ (m ³ )) of powdered concrete is added to the pocket 13 of each container 12 (i.e., each through-hole 21 of the measuring member 2 has a capacity of 1 (mL)). Note that these numerical values are merely examples and can be changed as appropriate.

First, the concentration of chloride ions detectable by the reagent L in the rightmost container 12a in Fig. 5 will be described. As shown in the above formula (1), 1 mole of silver ions Ag ⁺ reacts with 1 mole of chloride ions Cl ^- . The molecular weight of chloride ions is 35.5. For example, when the reagent L in the container 12a has a silver nitrate concentration of 0.01 (mol/L), the reagent L in the container 12a can detect chloride ions with a weight shown in the following formula (3).
0.01 (mol/L) x 5 x 10 ^-3 (L) x 35.5 = 1.8 x 10 ^-3 (g)
=1.8× ^10-6 (kg)
...(3)

As described above, 1 (mL) (=1 (cm ³ ) = 1 × 10 ^-6 (m ³ )) of powdered concrete is added to the pocket 13 of each container 12, and therefore the concentration of chloride ions detectable by reagent L in container 12a is given by the following formula (4).
1.8×10 ⁻⁶ (kg)/1×10 ⁻⁶ (m ³ )=1.8 (kg/m ³ )
...(4)

Container 12a has a mark 14a near pocket 13a that indicates the concentration of chloride ions detectable by reagent L in container 12a, calculated from formula (4) above (e.g., 1.8).

The same description will be given for the concentrations of chloride ions detectable by the reagent L in the other containers 12b, 12c, 12d, and 12e. For example, when the reagent L in the containers 12b, 12c, 12d, and 12e has a silver nitrate concentration of 0.02, 0.03, 0.04, and 0.05 (mol/L), respectively, the concentrations of chloride ions detectable by the reagent L in the containers 12b, 12c, 12d, and 12e are calculated to be 3.6, 5.3, 7.1, and 8.9 (kg/ ^m3 ), respectively, from the above formulas (3) and (4). The containers 12b, 12c, 12d, 12e have markings 14b, 14c, 14d, 14e adjacent the pockets 13b, 13c, 13d, 13e, respectively, which indicate the concentration of chloride ions detectable by the silver nitrate solution in the containers 12b, 12c, 12d, 12e, respectively (e.g., 3.6, 5.3, 7.1, 8.9).

The marks 14a, 14b, 14c, 14d, and 14e can be, for example, numerical values. Alternatively, the marks 14a, 14b, 14c, 14d, and 14e can be symbols to which numerical values are pre-assigned.

As described above, the concentration of chloride ions can be estimated based on the change in color of the silver nitrate solution in a set of containers 12. In the example of Fig. 5, the reagent L in the containers 12e, 12d, and 12c has turned brown (i.e., the reagent L contains silver oxide Ag ₂ O). Of these, the container 12 having the reagent L with the lowest silver nitrate concentration is the container 12c. The reagent L in the containers 12b and 12a has not turned brown (i.e., the reagent L does not contain silver oxide Ag ₂ O). Of these, the container 12 having the reagent L with the highest silver nitrate concentration is the container 12b.

Since the reagent L in the container 12c has turned brown, all of the chloride ions Cl ⁻ in the reagent L in the container 12c have been used in the reaction (1), whereas since the reagent L in the container 12b has not turned brown, some of the chloride ions Cl ⁻ in the reagent L in the container 12b have not been used in the reaction (1). Therefore, the concentration of chloride ions in the sample S is between "5.3 (kg/m ³ )" indicated by the mark 14c and "3.6 (kg/m ³ )" indicated by the mark 14b. However, when evaluating deterioration of concrete, it is safer to estimate the concentration of chloride ions on the high side. Therefore, in the example of FIG. 5, the concentration of chloride ions may be measured as 5.3 (kg/m ³ ). In this way, when the multiple reagents L include both one or more reagents L that have turned brown and one or more reagents L that have not turned brown, the concentration of chloride ions may be measured as the concentration detectable by the reagent L with the lowest concentration among the one or more reagents L that have turned brown.

When all of the reagents L turn brown, the chloride ion concentration is equal to or lower than the concentration detectable by the container 12a having the lowest concentration of the reagent L (a value of 1.8 (kg/m ³ ) or lower in the example of FIG. 5 ). Therefore, in this case, the chloride ion concentration may be measured to be equal to or lower than 1.8 (kg/m ³ ). When all of the reagents L do not turn brown, the chloride ion concentration is higher than the concentration detectable by the container 12e having the highest concentration of the reagent L (a value higher than 8.9 (kg/m ³ ) in the example of FIG. 5 ). Therefore, in this case, the chloride ion concentration may be measured to be greater than 8.9 (kg/m ³ ).

[Concentration measurement method]
The concentration measurement method will be described in detail below.

Figure 6 is a flowchart showing a method according to an embodiment. First, a plurality of liquid reagents L with different concentrations are prepared (step S100). In this embodiment, the above-mentioned kit 100 is prepared.

Next, a powdered sample S is prepared (step S102). For example, the powdered concrete can be obtained from the concrete structure of the maintenance target by a tool such as a grinder or a drill. For example, the sample S from the surface of the concrete structure can be obtained by a grinder. Also, the sample S from the inside of the concrete structure can be obtained by a drill. A sufficient amount of concrete may be obtained to fill all the through holes 21 of the measuring member 2. Alternatively, for example, when the concentration of chloride ions in the concrete can be predicted in advance, a sufficient amount of concrete may be obtained to fill at least two through holes 21. When obtaining the powdered concrete by a grinder or a drill, the amount of concrete removed from the concrete structure is smaller than the core (for example, the diameter of the drill hole is about 1 cm, and the diameter of the core is about 10 cm). Therefore, obtaining the powdered concrete by a grinder or a drill does not damage the concrete structure as compared to obtaining a core from the concrete structure. The powdered concrete has a size of, for example, about 1 μm to 100 μm, but is not limited thereto.

Then, the containers 12 are opened (step S104). If the sample S is to be added to all of the reagents L, all of the containers 12 are opened. Alternatively, if the sample S is to be added to only some of the reagents L, only the relevant containers 12 (at least two containers 12) may be opened.

Next, a specified amount of sample S is added to each of the liquid reagents L (step S106). With reference to FIG. 3, in this embodiment, first, the lid 3 is placed on the plate 10, and the measuring member 2 is placed on the lid 3. The measuring member 2 is positioned relative to the plate 10 so that the multiple through holes 21 face the multiple pockets 13. In order to easily position the measuring member 2 relative to the plate 10, a groove for positioning the measuring member 2 may be provided on the upper surface of the lid 3, and a groove for positioning the plate 10 may be provided on the lower surface of the lid 3 (not shown). Next, the sample S is placed in the through hole 21 facing the pocket 13 of the opened container 12. For example, the sample S may be placed in the through hole 21 by the spoon 4, and excess sample S may be removed by the spoon 4 so that the upper surface of the sample S is flush with the upper surface of the measuring member 2. By such an operation, a specified amount of sample S can be placed in the through hole 21. Next, the lid 3 is removed from between the plate 10 and the measuring member 2. The sample S falls into each pocket 13. As described above, when the upper and lower surfaces of the lid 3 are provided with positioning grooves, the grooves may open to the side so that the lid 3 can be slidably removed from between the plate 10 and the measuring member 2. Through the above steps, a specified amount of sample S is added to each of the liquid reagents L.

Referring to FIG. 6, the reagent L is then shaken (step S108). In this embodiment, the plate 10 is closed with the lid 3, and the plate 10 is shaken. Next, the concentration of the components in the sample S is measured based on the change in the reagent L in the container 12 to which the sample S has been added (step S110). In this embodiment, as described above, the concentration of chloride ions in the powdered concrete is measured based on the change in color of the silver nitrate solution in the container 12 to which the powdered concrete has been added.

The kit 100 according to the embodiment described above includes a set of liquid reagents L with different concentrations and a set of sealed containers 12 that contain the set of liquid reagents L. The method according to the embodiment described above includes a step of preparing a plurality of liquid reagents L with different concentrations, a step of preparing a powder sample S, a step of adding a specified amount of the powder sample S to each of the plurality of liquid reagents L, and a step of measuring the concentration of a specific component in the powder sample S based on the change in the plurality of liquid reagents L. According to these kits 100 and methods, it is possible to measure the concentration of a specific component in the sample S by simply adding the powder sample S to the reagent L without preparing a solution containing the sample S in advance. Therefore, it is possible to reduce the burden on the operator by eliminating the need to prepare a solution containing the sample S in advance. In addition, in the kit 100, the container 12 is sealed by a seal member 11. Therefore, it is possible to prevent the reagent L from spilling from the container 12 before use. Therefore, the kit 100 has excellent portability.

In the above embodiment of the kit 100, the set of sealed containers 12 is integral (plate 10). Therefore, the kit 100 has excellent portability.

The kit 100 of the above embodiment includes a measuring member 2 that is disposed opposite a plurality of pockets 13 of a set of sealed containers 12 and includes a plurality of through holes 21, each having a predetermined volume. Therefore, a specified amount of sample S can be easily prepared by simply placing sample S in the through holes 21.

The kit 100 of the above embodiment includes a lid 3 that covers the multiple pockets 13 and the multiple through-holes 21. Therefore, when the sample S is placed in the through-hole 21 of the measuring member 2, the lid 3 can prevent the sample S from falling out of the through-hole 21 before a specified amount of the sample S is accumulated in the through-hole 21. This allows a specified amount of sample S to be accurately prepared. In addition, the container 12 can be closed with the lid 3 when the reagent L is shaken.

In the kit 100 of the above embodiment, the multiple pockets 13 contain the same amount of reagent L, and the multiple through holes 21 have the same capacity. If the multiple pockets 13 contain different amounts of reagent L and the multiple through holes 21 have different capacities, an incorrect combination of pockets 13 and through holes 21 will result in an amount of sample S different from the specified amount being erroneously added to the reagent L. In the above embodiment, the multiple pockets 13 contain the same amount of reagent L, and the multiple through holes 21 have the same capacity, so that even if an incorrect combination of pockets 13 and through holes 21 is made, it is possible to prevent an amount of sample S different from the specified amount being erroneously added to the reagent L.

In the above embodiment of the kit 100, each container 12 has a mark 14 that indicates the concentration detectable by the reagent L in that container 12. Therefore, the approximate measured concentration can be easily known.

In the above embodiment of the kit 100, the multiple liquid reagents L are silver nitrate solutions. Therefore, the concentration of chloride ions in the sample S can be measured.

Although the embodiments have been described above with reference to the attached drawings, the present disclosure is not limited to the above-described embodiments. It is clear to those skilled in the art that various changes or modifications can be made within the scope of the claims, and it is understood that these also fall within the technical scope of the present disclosure. In addition, the steps of the method of the above-described embodiments do not have to be performed in the above order, and may be performed in a different order as long as no technical contradiction occurs.

For example, the above embodiment of the kit 100 is described as measuring the concentration of chloride ions in concrete. However, the kit 100 may be used to measure the concentration of chloride ions in samples other than concrete.

The kit 100 of the above embodiment includes a silver nitrate solution as the reagent L to measure the concentration of chloride ions. Alternatively, the kit 100 may be configured to measure the concentration of other components than chloride ions. For example, the kit 100 may include a plurality of acid-base indicators (e.g., phenolphthalein solutions) of different concentrations as the reagent L. In this case, for example, the kit 100 can measure the concentration of calcium hydroxide in concrete. In other words, the kit 100 can determine the degree of neutralization of concrete. For example, the phenolphthalein solution is transparent when the pH is 8 or less, turns pink when the pH is about 8, turns red when the pH is about 9, and turns reddish purple when the pH is about 10 or more. Therefore, the kit 100 may include a set of phenolphthalein solutions having different concentrations by orders of magnitude, such as 1%, 0.1%, 0.01%, and 0.001%, as the reagent L to measure the degree of neutralization of concrete.

In the above embodiment of the kit 100, the set of sealed containers 12 is an integrated unit. However, the set of sealed containers 12 may be separate members. In this case, a sealing member 11 is provided for each container 12. In this case, it is convenient, for example, because when only a portion of the reagent L is used, the remaining reagent L can be saved.

The kit 100 in the above embodiment includes a measuring member 2. However, the kit 100 does not have to include a measuring member 2. In this case, the powdered concrete may be added individually to each container 12 using a measuring device such as a measuring spoon.

The kit 100 in the above embodiment includes a lid 3. However, the kit 100 does not have to include the lid 3. In this case, the worker may, for example, separately prepare a flat plate instead of the lid 3.

In the kit 100 of the above embodiment, the multiple pockets 13 contain the same amount of reagent L. However, the multiple pockets 13 may contain different amounts of reagent L that are determined in advance. In this case, the amount of sample S to be added to each pocket 13 is calculated in advance, and the calculated amount of sample S is added to the corresponding pocket 13, thereby making it possible to perform measurements similar to those of the above embodiment. For example, each through-hole 21 of the measuring member 2 may have a capacity corresponding to the corresponding pocket 13.

In the above embodiment of the kit 100, each container 12 has a mark 14. However, each container 12 does not have to have a mark 14. In this case, the kit 100 may include instructions indicating the concentration of the component detectable by the reagent L in each container 12.

In the method of the above embodiment, in step S100, the kit 100 is prepared. Alternatively, in step S100, multiple liquid reagents L of different concentrations may be prepared separately from the kit 100. For example, the reagent L having a predefined concentration may be poured into a container. In this case, for example, step S104 is not required.

2 Measuring member 3 Lid 12, 12a to 12e Container 13, 13a to 13e Pocket 14, 14a to 14e Mark 21 Through hole 100 Kit L Reagent S Sample

Claims (6)

A set of liquid reagents of different concentrations;
a set of sealed containers including a plurality of pockets for containing the set of liquid reagents;
a measuring member including a plurality of through holes disposed opposite the plurality of pockets, each of the through holes having a predetermined volume;
A kit for measuring concentration. The kit for measuring a concentration according to claim 1 , further comprising a cover for covering the plurality of pockets and the plurality of through-holes. 3. The kit for measuring a concentration according to claim 2 , wherein the plurality of pockets contain the same amount of reagent, and the plurality of through-holes have the same capacity. The kit for measuring a concentration according to any one of claims 1 to 3 , wherein each container has a mark indicating a concentration detectable by the reagent in that container. 5. The kit for measuring a concentration according to claim 1 , wherein the set of liquid reagents is a silver nitrate solution. Providing a set of unitary sealed containers including a plurality of pockets containing a plurality of liquid reagents of different concentrations;
Preparing a powdered sample;
adding a defined amount of the powdered sample to each of the liquid reagents using a metering member including a plurality of through-holes, each having a predetermined volume, the through-holes being disposed opposite the pockets, and the powdered sample being added to each of the liquid reagents through the through-holes;
measuring the concentration of a specific component in the powder sample based on the changes in the plurality of liquid reagents;
A method for measuring concentration comprising: