JP6777915B2 - Analytical method and analyzer - Google Patents

Description

The present invention relates to an analytical method and an analyzer for quantifying tetrafluoroboric acid in a liquid containing tetrafluoroboric acid.

Conventionally, as a method of analyzing a tetrafluoroboric acid in the waste water quickly simply, the liquid film type BF ₄ ^- electrode contacting a test solution has been known a method of measuring the tetrafluoroborate (Patent Document 1 reference).

Japanese Unexamined Patent Publication No. 2011-27722

However, in the method for measuring tetrafluoroboric acid described in Patent Document 1, since fluctuations in pH and ionic strength directly affect the measured values, the pH and ions of the BF ^4- standard solution used for calibrating the BF ₄ ^- electrode. There is a problem that accurate measurement is impossible unless the intensity is adjusted so as to be close to the pH and ionic strength of the test solution. Therefore, when analyzing a test solution containing a substance other than tetrafluoroboric acid, in order to adjust the pH and ionic strength, a chemical such as a pH adjuster and an ionic strength adjuster is added, and dilution with a diluent is used. There was a problem that the operation was complicated. In addition, if the test solution contains interfering substances, tetrafluoroboric acid may not be quantified by the ion electrode method.

The present invention has been made in view of the above problems, and an object of the present invention is to use tetrafluoroboric acid in a liquid containing tetrafluoroboric acid even if the liquid contains a substance other than tetrafluoroboric acid. It is an object of the present invention to provide an analysis method and an analyzer capable of quantitative analysis without complicated electrode calibration and regardless of interfering substances.

The present invention includes the inventions shown in the following [1] to [7].
[1] An analytical method for quantifying tetrafluoroboric acid in a liquid containing tetrafluoroboric acid, which comprises the following (A) or (B).
(A) A step of quantifying fluorine in a sample liquid to determine the total amount of fluorine.
The process of quantifying the fluorine ions in the sample liquid to determine the amount of fluorine ions, and
Step of calculating the amount of fluorine derived from tetrafluoroboric acid in the sample liquid by the following formula (1) (amount of fluorine derived from tetrafluoroboric acid in the sample liquid) = {(total amount of fluorine)-(fluorine ion) Amount)} × Correction coefficient A ... Equation (1)
(In the formula (1), the correction coefficient A = 100 / (100-{(amount of fluorine ions in the sample liquid after adding a standard solution containing only a known amount of tetrafluoroboric acid)-(add the standard solution). The amount of fluorine ions in the sample liquid before the preparation)} / (the amount of fluorine derived from the tetrafluoroboric acid in the added standard liquid) × 100).
(B) A step of quantifying boron in a sample liquid to determine the total amount of boron.
A step of quantifying boron ions in a sample liquid to determine the amount of boron ions, and
A step of calculating the amount of boron derived from tetrafluoroboric acid in the sample liquid by the following formula (2).
(Amount of boron derived from tetrafluoroboric acid in sample liquid) = {(total amount of boron)-(amount of boron ions)} × correction coefficient B ... Equation (2)
(In the formula (2), the correction coefficient B = 100 / (100-{(amount of boron ions in the sample liquid after adding a standard solution containing only a known amount of tetrafluoroboric acid)-(add the standard solution). The amount of boron ions in the sample liquid before the preparation)} / (the amount of boron derived from tetrafluoroboric acid in the added standard liquid) × 100).
[2] Further, the amount of tetrafluoroboric acid in the sample liquid is determined from the amount of fluorine derived from the amount of tetrafluoroboric acid in the sample liquid or the amount of boron derived from the amount of tetrafluoroboric acid in the sample liquid. The analysis method according to [1], which comprises a step of calculating.
[3] The analysis method according to [1] or [2], further comprising a step of determining a correction coefficient A or a step of determining a correction coefficient B.
[4] The total amount of fluorine is quantified by distillation-lantern alizaline complex absorptiometry, distillation-ion electrode method, or distillation-lantern alizarin complex absorptiometry by flow analysis, and the amount of fluorine ions is quantified by ion chromatography. , The analysis method according to any one of [1] to [3], which is quantified by an ion electrode method, a lanthanum alysine complex absorptiometry, or a lanthanum alysine complex absorptiometry by a flow analysis method.
[5] The total amount of boron is quantified by acid decomposition-ICP emission spectrometric analysis, acid decomposition-ICP mass spectrometry, or thermal decomposition flow analysis, and the amount of boron ions is determined by ion chromatography, azomethine H method, or The analysis method according to any one of [1] to [3], which is quantified by the azomethine H method by a flow analysis method.
[6] An analyzer for quantifying tetrafluoroboric acid in a liquid containing tetrafluoroboric acid, which comprises the following (C) or (D).
(C) A total fluorine amount quantifying device, a fluorine ion amount quantifying device, and an input unit for inputting a correction coefficient A are provided, and the total fluorine amount output from the total fluorine amount quantifying device and the fluorine ion amount quantifying device are output. An arithmetic device for calculating the amount of tetrafluoroboric acid in the sample liquid from the amount of fluorine ions and the correction coefficient A, where the correction coefficient A = 100 / (100-{(known amount of tetrafluoroboric acid) Amount of fluorine ions in the sample liquid after adding the standard solution containing only)-(Amount of fluorine ions in the sample liquid before adding the standard solution)} / (Tetrafluoroboric acid in the added standard solution The amount of fluorine derived from) × 100).
(D) A total boron amount quantifying device, a boron ion amount quantifying device, and an input unit for inputting a correction coefficient B are provided, and the total boron amount output from the total boron amount quantifying device and the boron ion amount quantifying device are output. An arithmetic device for calculating the amount of tetrafluoroboric acid in the sample liquid from the amount of boron ions and the correction coefficient B, where the correction coefficient B = 100 / (100-{(known amount of tetrafluoroboric acid) Amount of boron ions in the sample liquid after adding the standard solution containing only)-(Amount of boron ions in the sample liquid before adding the standard solution)} / (Tetrafluoroboric acid in the added standard solution The amount of boron derived from) × 100).
[7] At least one of the total fluorine amount quantifying device and the fluorine ion amount quantifying device, or at least one of the total boron amount quantifying device and the boron ion amount quantifying device is a flow analyzer. The analyzer according to [6].

According to the method for quantitative analysis of tetrafluoroboric acid in a liquid containing tetrafluoroboric acid according to the present invention, complicated electrodes are calibrated for tetrafluoroboric acid in a liquid containing tetrafluoroboric acid. It has the effect of being able to perform quantitative analysis easily and quickly.

It is a figure which shows the schematic structure of the analyzer of the tetrafluoroboric acid which concerns on one Embodiment of this invention. (A) is a figure which shows an example of the total boron amount quantifying apparatus which is a part of the structure of the tetrafluoroboric acid analyzer which concerns on one Embodiment of this invention. (B) is a figure which shows an example of the boron ion amount quantifying apparatus which is a part of the structure of the tetrafluoroboric acid analyzer which concerns on one Embodiment of this invention.

Hereinafter, embodiments of the present invention will be described in detail. However, the present invention is not limited to this, and various modifications can be made within the range described, and the present invention also relates to an embodiment obtained by appropriately combining the technical means disclosed in each of the different embodiments. Included in the technical scope of. Unless otherwise specified in the present specification, "A to B" representing a numerical range means "A or more and B or less". Also, "mass" and "weight" are considered to be synonymous.

The analytical method according to an embodiment of the present invention is an analytical method for quantifying tetrafluoroboric acid in a liquid containing tetrafluoroboric acid, and includes the following (A) or (B). Hereinafter, "analytical method for quantifying tetrafluoroboric acid in a liquid containing tetrafluoroboric acid" may be referred to as "analytical method for tetrafluoroboric acid". Further, the analysis method including (A) may be referred to as "analysis method A", and the analysis method including (B) may be referred to as "analysis method B".
(A) A step of quantifying fluorine in a sample liquid to determine the total amount of fluorine.
The process of quantifying the fluorine ions in the sample liquid to determine the amount of fluorine ions, and
Step of calculating the amount of fluorine derived from tetrafluoroboric acid in the sample liquid by the following formula (1) (amount of fluorine derived from tetrafluoroboric acid in the sample liquid) = {(total amount of fluorine)-(fluorine ion) Amount)} × Correction coefficient A ... Equation (1)
(In the formula (1), the correction coefficient A = 100 / (100-{(amount of fluorine ions in the sample liquid after adding a standard solution containing only a known amount of tetrafluoroboric acid)-(add the standard solution). The amount of fluorine ions in the sample liquid before the preparation)} / (the amount of fluorine derived from the tetrafluoroboric acid in the added standard liquid) × 100).
(B) A step of quantifying boron in a sample liquid to determine the total amount of boron.
A step of quantifying boron ions in a sample liquid to determine the amount of boron ions, and
A step of calculating the amount of boron derived from tetrafluoroboric acid in the sample liquid by the following formula (2).
(Amount of boron derived from tetrafluoroboric acid in sample liquid) = {(total amount of boron)-(amount of boron ions)} × correction coefficient B ... Equation (2)
(In the formula (2), the correction coefficient B = 100 / (100-{(amount of boron ions in the sample liquid after adding a standard solution containing only a known amount of tetrafluoroboric acid)-(add the standard solution). The amount of boron ions in the sample liquid before the preparation)} / (the amount of boron derived from tetrafluoroboric acid in the added standard liquid) × 100).
The liquid containing tetrafluoroboric acid may be any liquid as long as it contains tetrafluoroboric acid. The liquid is preferably a liquid containing water. For example, the liquid may be groundwater, hot spring water, swamp lake water, seawater, factory effluent, mine effluent, river water, fresh water purified from seawater by RO membrane, etc., containing tetrafluoroboric acid. For example, in wastewater from glass manufacturing factories and plating factories containing high concentrations of fluorine and boron, fluorine and boron are combined in an acidic region to produce persistent tetrafluoroboric acid. In the treatment of such wastewater, it is necessary to grasp the accurate content of tetrafluoroboric acid in the wastewater for stable treatment.

The liquid containing tetrafluoroboric acid may contain various substances in addition to tetrafluoroboric acid. According to the analysis method according to the embodiment of the present invention, tetrafluoroboric acid in a liquid containing various substances can be suitably quantified. Further, according to the analysis method according to the embodiment of the present invention, tetrafluoroboric acid in a liquid containing tetrafluoroboric acid and hexafluorosilicic acid can also be suitably quantified.

(I) Analysis method A
The method for analyzing tetrafluoroboric acid according to an embodiment of the present invention includes a step of quantifying fluorine in a sample liquid to determine the total amount of fluorine (hereinafter, may be referred to as a total fluorine amount quantification step), and a sample liquid. Derived from tetrafluoroboric acid in the sample liquid by a step of quantifying the fluorine ions in the sample and measuring the amount of fluorine ions (hereinafter, may be referred to as a fluorine ion amount quantification step) and the following formula (1). Step to calculate the amount of fluorine (hereinafter, may be referred to as the step to calculate the amount of fluorine derived from tetrafluoroboric acid)
(Amount of fluorine derived from tetrafluoroboric acid in sample liquid) = {(total amount of fluorine)-(amount of fluorine ions)} × correction coefficient A ... Equation (1)
(In the formula (1), the correction coefficient A = 100 / (100-{(amount of fluorine ions in the sample liquid after adding a standard solution containing only a known amount of tetrafluoroboric acid)-(add the standard solution). The amount of fluorine ions in the sample liquid before the preparation)} / (the amount of fluorine derived from the tetrafluoroboric acid in the added standard liquid) × 100)).

In the present invention, the "total fluorine amount" is intended to be an elemental equivalent amount of all fluorine contained in the sample liquid. The total amount of fluorine is the amount of fluorine other than fluorine ions derived from tetrafluoroboric acid (bonded to boron), and is generated by dissociation of tetrafluoroboric acid in the sample liquid. The amount of fluorine ions and the amount of fluorine ions not derived from tetrafluoroboric acid. In the present embodiment, the "fluorine ion amount" is intended to be the amount of all fluorine ions (F ⁻ ) contained in the sample liquid. The amount of fluorine ions is an amount including the amount of fluorine ions derived from tetrafluoroboric acid and the amount of fluorine ions not derived from tetrafluoroboric acid.

(I-1 Total Fluorine Amount Quantification Step)
In this step, quantifying the amount of fluorine in the sample liquid means quantifying the amount of fluorine in all forms contained in the sample liquid in terms of elements.

In the present embodiment, as a method for quantifying fluorine in the sample liquid and measuring the total amount of fluorine, for example, distillation-lanthanum alizarin complexone absorptiometry, distillation-ion electrode method, distillation by flow analysis method-lantern alizarin Examples include the distillation-ion electrode method by the complexon absorptiometry and the flow analysis method.

Distillation-Lanthan alizarin complex absorptiometry is a method in which a sample liquid is distilled and then the distillate is measured by the lanthanum alizarin complex absorptiometry. The lanthanum alizarin complex absorptiometry is a method for quantifying fluorine ions by utilizing the formation of a blue complex when fluorine ions react with a complex of lanthanum and alizarin.

In the distillation-ion electrode method, after distilling the sample liquid, an ion-selective electrode (ion sensor) that selectively responds to fluorine ions and a comparison electrode are inserted into the obtained sample as distillates, and both electrodes are used. This is a method of quantifying fluorine ions from the potential difference generated between them. As the distillation-ion electrode method, the method specified in ISO10359-2 can be preferably used.

Distillation-lanthanum alizarin complex absorptiometry by flow analysis method is a method of performing distillation-lanthanum alizarin complex absorptiometry by flow analysis method. The flow analysis method is, for example, the method specified in JIS K 0126. The flow analysis method may be a continuous flow analysis method (CFA) or a flow injection analysis method (FIA).

As the distillation-lanthanum alizarin complexone absorptiometry method by the flow analysis method, for example, the distillation-lanthanum alizarin complexone coloring CFA method, which is a method specified in JIS K 0170-6 6.3.3, is preferably used. be able to. Specifically, in the distillation-lanthanum allizarin complexone coloring CFA method, the sample liquid and the distillation reagent solution are continuously mixed and distilled in a capillary tube. The fraction obtained by distillation and the lanthanum alizarin solution are mixed in a stream and reacted, and then the absorbance of the blue compound produced by the reaction near 620 nm is measured to quantify fluorine.

Alternatively, after distillation as a pretreatment, the distillation-lanthanum alizarin complexone coloring FIA method, which is the method specified in JIS K 0170-6 6.3.2, may be used. Distillation-Lanthanum Alizarin Complexon Coloring In the FIA method, a distillation pretreated sample is injected into a carrier solution that continuously flows through a capillary tube, and the sample is mixed and reacted with the lanthanum alizarin solution in the flow. After that, the absorbance of the blue compound produced by the reaction near 620 nm is measured, and fluorine is quantified.

Perfluorooctanoic acid (PFOS) and perfluorooctanoic acid (PFOA), which are persistent fluorine compounds, are not decomposed by distillation. On the other hand, other fluorine compounds including tetrafluoroboric acid are decomposed by distillation. Therefore, by using a method including a distillation operation as a pretreatment, PFOS and PFOA can be separated from other fluorine compounds, so that the quantitative measurement error of total fluorine becomes small and the final calculation is performed. The error in the amount of tetrafluoroboric acid can be reduced.

(I-2 Fluorine ion amount quantification step)
In the present embodiment, the method of quantifying the fluorine ions in the sample liquid and measuring the amount of the fluorine ions is not limited to this, but for example, an ion chromatography method, an ion electrode method, or a lanthanum alizarin complexone absorption. Examples thereof include a lanthanum alysine complexone absorptiometry by a photometric method and a flow analysis method, and an ion electrode method by a flow analysis method.

The ion chromatography method may be carried out by a conventional method, but for example, the method specified in JIS K 0127 can be preferably used.

The ion electrode method, the lanthanum alizarin complex absorptiometry, and the lanthanum alizarin complex absorptiometry by the flow analysis method are as described in I-1 above, except that distillation is not performed as a pretreatment. Therefore, the description is omitted here.

The combination of the measuring method used in the total fluorine amount quantification step and the measuring method used in the present fluorine ion amount quantification step is not particularly limited, and any combination is possible. Among them, when the distillation-lantern alizarin complexone absorptiometry method by the flow analysis method is used in the total fluorine amount quantification step and the lantern alizarin complexone absorptiometry method by the flow analysis method is used in the fluorine ion amount quantification step. , The total amount of fluorine and the amount of fluorine ions can be easily and automatically quantified. Further, if it is connected to a calculation device for performing a step of calculating the amount of fluorine derived from tetrafluoroboric acid and a step of calculating the amount of tetrafluoroboric acid in the sample liquid, which will be described later, the amount of tetrafluoroboric acid in the sample liquid is automatically calculated. Can be measured with. Therefore, 24-hour continuous monitoring of the sample liquid is also possible.

(I-3 Fluoroboric Acid Derived Fluorine Amount Calculation Step)
In this step, the following formula (1) is obtained from the total amount of fluorine in the sample liquid obtained in the total fluorine amount quantification step and the amount of fluorine ions in the sample liquid obtained in the fluorine ion amount quantification step. The amount of fluorine derived from tetrafluoroboric acid in the sample liquid is calculated as described above. Here, the amount of fluorine derived from tetrafluoroboric acid in the sample liquid is derived from fluorine (bonded to boron) other than fluorine ions and tetrafluoroboric acid existing in the form of fluorine ions. Refers to all fluorine.
(Amount of fluorine derived from tetrafluoroboric acid in sample liquid) = {(total amount of fluorine)-(amount of fluorine ions)} × correction coefficient A ... Equation (1)
In formula (1), correction coefficient A = 100 / (100-{(amount of fluorine ions in the sample liquid after adding a standard solution containing only a known amount of tetrafluoroboric acid)-(add the standard solution). The amount of fluorine ions in the previous sample liquid)} / (the amount of fluorine derived from the tetrafluoroboric acid in the added standard liquid) × 100).

The step of calculating the correction coefficient A (hereinafter, may be referred to as a correction coefficient A calculation step) does not need to be performed each time the measurement is performed as long as the origin of the sample liquid to be analyzed is the same. The determined correction coefficient A may be used. In the present specification, the origin of the sample liquid to be analyzed is the same, for example, in the case of wastewater from the same factory, groundwater, hot spring water, swamp lake water, seawater, river water, and RO membrane at the same point are used. Refers to fresh water purified from seawater. If the origin of the sample liquid to be analyzed is the same, the composition ratio of the contents of the components contained in the sample solution is also substantially the same, so that the correction coefficient A can be approximated to be the same. For sample liquids of the same origin, the correction coefficient A calculation step may be performed periodically. As a result, accurate quantification can be performed even when the components contained in the sample liquid fluctuate.

Tetrafluoroborate in a liquid (BF 4 ^_-) are considered to be stable. Tetrafluoroborate (BF 4 ^_-) if there as it submerged without decomposition, for the sample liquid to tetrafluoroboric acid and fluoride ions are mixed, fluorine ions from the total fluorine content of the sample liquid It can be said that the amount obtained by subtracting the amount is the amount of fluorine derived from tetrafluoroboric acid. However, when the present inventors measured the total amount of fluorine and the amount of fluorine ions in the standard solution containing only tetrafluoroboric acid, some fluorine was detected as fluorine ions with respect to the total amount of fluorine in tetrafluoroboric acid. I got the knowledge that it will be done.

Based on the above findings, the present inventors set the amount of fluorine derived from tetrafluoroboric acid in the liquid containing tetrafluoroboric acid to the amount obtained by subtracting the amount of fluorine ions from the total amount of fluorine in the sample liquid. We have found that it can be determined by multiplying the above-mentioned correction coefficient in order to correct the proportion of fluorine existing as fluorine ions, and have completed the present invention.

Hexafluorosilicic acid is also considered as a stable compound containing fluorine. Therefore, when the total amount of fluorine and the amount of fluorine ions of the standard solution containing only hexafluorosilicic acid were measured, hexafluorosilicic acid was found. It was found that almost all of the fluorine was detected as fluorine ions.

Based on the above findings, the method for analyzing tetrafluoroboric acid according to the present embodiment is effective even in a sample liquid containing hexafluorosilicic acid in addition to tetrafluoroboric acid. In a liquid containing fluorine, boron, and silicon, fluorine and boron, or fluorine and silicon react to exist as stable tetrafluoroborate ions and hexafluorosilicate ions. Therefore, tetrafluoroborate ion, hexafluorosilicate ion, and fluorine ion are often mixed in the treatment site such as water treatment. Even in such a case, the analysis method according to the present embodiment is very useful.

In addition to the hexafluorosilicic acid, there are the above-mentioned perfluorooctanoic acid (PFOS) and perfluorooctanoic acid (PFOA) as fluorine compounds that may not be detected as fluorine ions. The method for reducing the error based on perfluorooctanoic acid (PFOS) and perfluorooctanoic acid (PFOA) is as described above.

(I-4 Step of calculating the amount of tetrafluoroboric acid in the sample liquid)
The amount of fluorine obtained in the step of calculating the amount of fluorine derived from tetrafluoroboric acid is an index indicating the amount of tetrafluoroboric acid in the sample liquid, and the amount of tetrafluoroboric acid according to the embodiment of the present invention. The analysis method may further include a step of calculating the amount of tetrafluoroboric acid in the sample liquid from the amount of fluorine derived from the amount of tetrafluoroboric acid in the sample liquid.

The amount of tetrafluoroboric acid in the sample liquid may be calculated by weight or by molar amount. For example, when calculating by weight, the amount of tetrafluoroboric acid in the sample liquid can be calculated by the following formula (4).
(Amount of tetrafluoroboric acid in sample liquid) = (Amount of fluorine derived from tetrafluoroboric acid in sample liquid) x (Molecular weight of tetrafluoroboric acid) / (Amount of fluorine element in tetrafluoroboric acid) ... Equation (4)
(I-5 correction coefficient A calculation process)
In the step of calculating the amount of fluorine derived from tetrafluoroboric acid, the correction coefficient A determined in advance by the method described above may be used as the correction coefficient A, but the analysis of tetrafluoroboric acid according to the embodiment of the present invention. The method may further include a step of calculating the correction coefficient A.

In this step, the amount of fluorine ions in the sample liquid after the addition of the standard solution containing only a known amount of tetrafluoroboric acid, the amount of fluorine ions in the sample liquid before the addition of the standard solution, and the addition of the above. The correction coefficient A is calculated from the amount of fluorine derived from tetrafluoroboric acid in the standard solution. At this time, the method of measuring the amount of fluorine ions in the sample liquid after adding the standard solution containing only a known amount of tetrafluoroboric acid is to quantify the fluorine ions in the sample liquid in the fluorine ion amount quantification step. It is preferable to carry out the same method as the method for determining the amount of fluorine ions.

(II) Analysis method B
The method for analyzing tetrafluoroboric acid according to an embodiment of the present invention includes a step of quantifying boron in a sample liquid to determine the total amount of boron (hereinafter, may be referred to as a total amount of boron quantification step), and a sample liquid. Derived from tetrafluoroboric acid in the sample liquid by a step of quantifying the boron ions in the sample to determine the amount of boron ions (hereinafter, may be referred to as a step of quantifying the amount of boron ions) and the following formula (2). Step of calculating the amount of boron (hereinafter, may be referred to as a step of calculating the amount of boron derived from tetrafluoroborate),
(Amount of boron derived from tetrafluoroboric acid in sample liquid) = {(total amount of boron)-(amount of boron ions)} × correction coefficient B ... Equation (2)
(In the formula (2), the correction coefficient B = 100 / (100-{(amount of boron ions in the sample liquid after adding a standard solution containing only a known amount of tetrafluoroboric acid)-(add the standard solution). The amount of boron ions in the sample liquid before the preparation)} / (the amount of boron derived from tetrafluoroboric acid in the added standard liquid) × 100)).

In the present embodiment, the "total boron amount" is intended to be an elemental equivalent amount of all boron contained in the sample liquid. The total amount of boron is the amount of boron derived from tetrafluoroboric acid that is bonded to fluorine atoms without dissociating in the sample liquid, and the amount of boron derived from tetrafluoroboric acid that is dissociated in the sample liquid. The amount of boron and the amount of boron not derived from tetrafluoroboric acid. In the present embodiment, the "boron ion amount" is intended to be the amount of all boron ions contained in the sample liquid. The amount of boron ions is an amount including the amount of boron derived from tetrafluoroboric acid that is dissociated in the sample liquid and the amount of boron that is not derived from tetrafluoroboric acid.

(II-1 Total Boron Amount Quantification Step)
In this step, quantifying boron in the sample liquid means quantifying the amount of boron in all forms contained in the sample liquid in terms of elements.

In the present embodiment, the method for quantifying boron in the sample liquid to determine the total amount of boron is not limited to this, but for example, acid decomposition-ICP emission spectrometric analysis, acid decomposition-ICP mass spectrometry. Methods, methylene blue absorptiometry, atomic absorption spectrophotometry, ion electrode method, methylene blue absorptiometry by flow analysis, thermal decomposition flow analysis and the like can be mentioned.

The acid decomposition-ICP emission spectroscopic analysis is a method of introducing a sample liquid into a high frequency inductively coupled plasma and measuring the emission intensity by boron to quantify total boron. In the acid decomposition-ICP mass analysis method, an internal standard element is added to the sample liquid and sprayed into a high-frequency plasma through the sample introduction part, and the indicated values at the respective mass numbers of boron and the internal standard element are measured, and the indicated value of boron is used. This is a method for quantifying total boron by obtaining the ratio with the indicated value of the internal standard element.

In the thermal decomposition flow analysis method, metal ions are added to the sample liquid by flow analysis, and then heated under acidic conditions to decompose tetrafluoroboric acid into boric acid, and then a coloring liquid is added to the sample liquid to obtain boron. This is a method for quantifying the total amount of boron by reacting with an acid and measuring the absorbance of the produced complex. As a more specific example, after adding aluminum ions to the sample liquid, it is heated to a temperature higher than 80 ° C. under acidic conditions to decompose tetrafluoroboric acid into boric acid, and then to the sample liquid. A method of quantifying the total amount of boron can be mentioned by adding azomethine H and reacting with boric acid and measuring the absorbance of the produced complex. From the viewpoint that the total amount of boron can be easily and automatically quantified, it is more preferable to quantify the total boron by the thermal decomposition flow analysis method in this step. The flow analysis method is, for example, the method specified in JIS K 0126. The flow analysis method may be a continuous flow analysis method (CFA) or a flow injection analysis method (FIA).

(II-2 Boron ion amount quantification step)
In the present embodiment, the method of quantifying the boron ions in the sample liquid to determine the amount of boron ions is not limited to this, but for example, ion chromatography method, azomethin H method, ion electrode method, flow. Azomethin H method by an analytical method and the like can be mentioned.

The ion chromatography method may be carried out by a conventional method, but for example, a method specified in JIS K 0127 can be used. The azomethine H method is a method for quantifying boron ions by measuring the absorbance of a yellow complex formed by the reaction of boric acid (boron ion) with azomethin H. The azomethine H method may be carried out by a conventional method, and for example, the method specified in JIS K 0102 47.2 can be used. From the viewpoint that boron can be easily quantified, it is more preferable to quantify boron ions by the azomethine H method in this step.

The flow analysis method is a method of quantifying the amount of boron ions by adding a coloring liquid to a sample liquid, reacting it with boric acid, and measuring the absorbance of the produced complex by flow analysis. As a more specific example, the azomethine H method by the flow analysis method can be mentioned. The azomethin H method by the flow analysis method is a method of quantifying the amount of boron ions by adding azomethin H to a sample liquid, reacting it with boric acid, and measuring the absorbance of the produced complex. The flow analysis method may be a continuous flow analysis method (CFA) or a flow injection analysis method (FIA).

The combination of the measuring method used in the total boron amount quantification step and the measuring method used in the present boron ion amount quantification step is not particularly limited, and any combination is possible. Above all, when the thermal decomposition flow analysis method is used in the total boron amount quantification step and the azomethine H method by the flow analysis method is used in the boron ion amount quantification step, the total boron amount and the boron ion amount are easily and automatically used. And can be quantified. Further, if it is connected to a calculation device for performing a step of calculating the amount of tetrafluoroboric acid-derived boron and a step of calculating the amount of tetrafluoroboric acid in the sample liquid, which will be described later, the amount of tetrafluoroboric acid in the sample liquid is automatically calculated. Can be measured with. Therefore, 24-hour continuous monitoring of the sample liquid is also possible.

(II-3 step of calculating the amount of boron derived from tetrafluoroboric acid)
In this step, the following formula (2) is obtained from the total boron amount in the sample liquid obtained in the total boron amount quantification step and the boron ion amount in the sample liquid obtained in the boron ion amount quantification step. The amount of boron derived from tetrafluoroborate in the sample liquid is calculated as described above. Here, the amount of boron derived from tetrafluoroboric acid in the sample liquid is the amount of boron derived from tetrafluoroboric acid that is bonded to a fluorine atom without dissociating in the sample liquid. And, it is an amount including the amount of boron dissociated in the sample liquid among the boron derived from tetrafluoroboric acid, and refers to all the boron derived from tetrafluoroboric acid.
(Amount of boron derived from tetrafluoroboric acid in sample liquid) = {(total amount of boron)-(amount of boron ions)} × correction coefficient B ... Equation (2)
In formula (2), correction coefficient B = 100 / (100-{(amount of boron ions in the sample liquid after adding a standard solution containing only a known amount of tetrafluoroboric acid)-(the standard solution is added. The amount of boron ions in the previous sample liquid)} / (the amount of boron derived from tetrafluoroboric acid in the added standard liquid) × 100).

The step of calculating the correction coefficient B (hereinafter, may be referred to as a correction coefficient B calculation step) does not need to be performed each time the measurement is performed as long as the origin of the sample liquid to be analyzed is the same. The correction coefficient B determined in advance may be used. If the origin of the sample liquid to be analyzed is the same, the composition ratio of the contents of the components contained in the sample solution is also substantially the same, so that the correction coefficient B can be approximated to be the same. For sample liquids of the same origin, the correction coefficient B calculation step may be performed periodically. As a result, accurate quantification can be performed even when the components contained in the sample liquid fluctuate.

When the present inventors measured the total amount of boron and the amount of boron ions in the standard solution containing only tetrafluoroboric acid, some boron was detected as boron ions with respect to the total amount of boron in tetrafluoroboric acid. I got the finding.

Based on the above findings, the present inventors determined that the amount of boron derived from tetrafluoroboric acid in the liquid containing tetrafluoroboric acid is the amount obtained by subtracting the amount of boron ions from the total amount of boron in the sample liquid. It was found that it can be determined by multiplying by a correction coefficient for correcting the proportion of boron existing as boron ions.

(II-4 Step of calculating the amount of tetrafluoroboric acid in the sample liquid)
The amount of boron obtained in the step of calculating the amount of boron derived from tetrafluoroboric acid is an index indicating the amount of tetrafluoroboric acid in the sample liquid, and the amount of tetrafluoroboric acid according to the embodiment of the present invention. The analysis method may further include a step of calculating the amount of tetrafluoroboric acid in the sample liquid from the amount of boron derived from the amount of tetrafluoroboric acid in the sample liquid.

The amount of tetrafluoroboric acid in the sample liquid may be calculated by weight or by molar amount. For example, when calculating by weight, the amount of tetrafluoroboric acid in the sample liquid can be calculated by the following formula (6).
(Amount of tetrafluoroboric acid in sample liquid) = (Amount of boron derived from tetrafluoroboric acid in sample liquid) × {(Molecular weight of tetrafluoroboric acid) / (Amount of boron element in tetrafluoroboric acid) … Equation (6)
(II-5 correction coefficient B calculation process)
In the step of calculating the amount of boron derived from tetrafluoroboric acid, the correction coefficient B determined in advance by the method described above may be used as the correction coefficient B, but the analysis of tetrafluoroboric acid according to the embodiment of the present invention. The method may further include a step of calculating the correction coefficient B.

In this step, the amount of boron ions in the sample liquid after the addition of the standard solution containing only a known amount of tetrafluoroboric acid, the amount of boron ions in the sample liquid before the addition of the standard solution, and the addition of the above. The correction coefficient B is calculated from the amount of boron derived from tetrafluoroboric acid in the standard solution. At this time, the method of measuring the amount of boron ions in the sample liquid after adding the standard solution containing only a known amount of tetrafluoroboric acid is to quantify the boron ions in the sample liquid in the boron ion amount quantification step. It is preferable to carry out the same method as the method for determining the amount of boron ions.

(III) Analyzer (III-1) Analyzer that implements analysis method B When the method for analyzing tetrafluoroboric acid according to one embodiment of the present invention is the analysis method B, in the total boron amount quantification step. Quantify the total boron amount and the boron ion amount by a total boron amount quantifying device for quantifying the total boron amount and a boron ion amount quantifying device for quantifying the boron ion amount in the boron ion amount quantifying step. Can be done. Further, the total boron amount quantifying device and the boron ion amount quantifying device are connected to a calculation device for performing a step of calculating the amount of boron derived from tetrafluoroboric acid and a step of calculating the amount of tetrafluoroboric acid in the sample liquid, which will be described later. Then, the amount of tetrafluoroboronic acid in the sample liquid can be calculated.

Therefore, one embodiment of the present invention includes a total boron amount quantifying device, a boron ion amount quantifying device, and an input unit for inputting a correction coefficient B, and the total boron amount output from the total boron amount quantifying device. Also included is a tetrafluoroboric acid analyzer, which includes an arithmetic device for calculating the amount of tetrafluoroboric acid in the sample liquid from the amount of boron ions output from the boron ion amount quantifying device and the correction coefficient B.

Here, the correction coefficient B, the total amount of boron, the amount of boron ions, and the amount of tetrafluoroboric acid in the sample liquid are as described in (II) above, and thus the description thereof will be omitted here.

An example of an analyzer in the case where the method for analyzing tetrafluoroboric acid is the above-mentioned analysis method B will be described in detail with reference to FIG.

As shown in FIG. 1, the analyzer includes a total boron amount quantifying device, a boron ion amount quantifying device, and an input unit for inputting a correction coefficient B, and the total boron amount output from the total boron amount quantifying device. The device is provided with a calculation device for calculating the amount of tetrafluoroboric acid in the sample liquid from the amount of boron ions output from the boron ion amount quantifying device and the correction coefficient B.

The total boron amount quantifying device shown in FIG. 1 is an device capable of quantifying the total boron amount by a continuous flow analysis method (CFA) (hereinafter, referred to as a CFA total boron amount quantifying device). The CFA total boron amount quantifying device is provided with a thin tube through which the sample passes, and is provided with a sample introduction part, a heater, a reaction part, and a detection part in this order with respect to the flow direction of the sample in the thin tube. The CFA total boron amount quantifying device further includes an air introduction section and a metal ion-containing liquid introduction section between the sample introduction section and the heater in this order, and further provides a coloring liquid introduction section between the heater and the reaction section. I have. With this configuration, the total amount of boron in the sample liquid can be quantified by the thermal decomposition flow analysis method by the continuous flow analysis method (CFA). That is, the sample liquid is introduced from the sample introduction part, the sample liquid is segmented by the bubbles introduced from the air introduction part, the metal ion is added to the sample liquid at the metal ion-containing liquid introduction part, and then the metal ion is added at the heating part. The sample solution to which is added is heated to decompose tetrafluoroboric acid into boric acid. After that, the color-developing liquid is added to the sample liquid from the color-developing liquid introduction unit, reacted with boric acid in the reaction unit, and the absorbance of the produced complex is measured in the detection unit, whereby the total amount of boron can be quantified.

The boron ion amount quantifying device shown in FIG. 1 is a device capable of measuring the boron ion amount by a continuous flow analysis method (CFA) (hereinafter, referred to as a CFA boron ion amount quantifying device). The CFA boron ion amount quantifying device is provided with a thin tube through which a sample passes, and is provided with a sample introduction part, a reaction part, and a detection part in this order with respect to the flow direction of the sample in the thin tube. The CFA boron ion amount quantifying device further includes an air introduction section and a color-developing solution introduction section between the sample introduction section and the reaction section in this order with respect to the flow direction of the sample in the capillary tube. With this configuration, the amount of boron ions in the sample liquid can be quantified by the azomethine H method by the continuous flow analysis method (CFA).

The total boron amount quantifier and the boron ion amount quantifier may further include a pump. As a result, the flow rate can be adjusted to feed the sample.

The arithmetic unit shown in FIG. 1 includes an input unit for inputting the correction coefficient B. The calculation device is in the sample liquid from the total boron amount output from the detection unit of the CFA total boron amount quantification device, the boron ion amount output from the detection unit of the CFA boron ion amount quantification device, and the correction coefficient B. Calculate the amount of tetrafluoroboronate in.

Further, instead of the CFA total boron amount quantifying device shown in FIG. 1, a device capable of quantifying the total boron amount by the flow injection analysis method (FIA) shown in FIG. 2 (a) (hereinafter, FIA total boron amount quantifying device). ) May be used.

The FIA total boron amount quantifying device shown in FIG. 2A includes a thin tube through which the carrier liquid continuously flows, and the carrier liquid introduction part, the heater, the reaction part, and the detection part are made of the carrier liquid in the thin tube. It is prepared in this order with respect to the flow direction. The FIA total boron amount quantifying device further includes a sample introduction section and a metal ion-containing liquid introduction section between the carrier liquid introduction section and the heater in this order, and a coloring liquid introduction section between the heater and the reaction section. Further prepared. With this configuration, the total amount of boron in the sample liquid can be quantified by the thermal decomposition flow analysis method by the flow injection analysis method (FIA).

Further, instead of the CFA boron ion amount quantifying device shown in FIG. 1, an apparatus capable of quantifying the boron ion amount by the flow injection analysis method (FIA) shown in FIG. 2 (b) (hereinafter, FIA boron ion amount quantifying device). ) May be used.

The FIA total boron amount quantifying device shown in FIG. 2B includes a thin tube through which the carrier liquid flows continuously, and the carrier liquid introduction part, the reaction part, and the detection part are set in the flow direction of the carrier liquid in the thin tube. On the other hand, it is prepared in this order. The FIA total boron amount quantifying device further includes a sample introduction unit and a color-developing liquid introduction unit between the carrier liquid introduction unit and the reaction unit in this order with respect to the flow direction of the carrier liquid in the capillary tube. With this configuration, the amount of boron ions in the sample liquid can be quantified by the azomethine H method by the flow injection analysis method (FIA).

Further, in the analyzer according to the embodiment of the present invention shown in FIG. 1, only the CFA total boron amount quantifying device may be replaced with the FIA total boron amount quantifying device shown in FIG. 2A, or CFA. Only the boron ion amount quantifying device may be replaced with the FIA boron ion amount quantifying device shown in FIG. 2 (b), and both the CFA total boron amount quantifying device and the CFA boron ion amount quantifying device are of the FIA method. It may be replaced with a quantifying device.

Further, FIG. 1 shows a device for performing quantification by a flow analysis method as a total boron amount quantifying device and a boron ion amount quantifying device, but the total boron amount quantifying device and the boron ion amount quantifying device are flow analysis. The device is not limited to the device that performs the quantification by the method, and may be an device that performs the quantification by the other method described above.

More preferably, at least one of the total boron amount quantifying device and the boron ion amount quantifying device is a flow analyzer.

(III-2) Analytical Device for Implementing Analytical Method A When the analytical method for tetrafluoroborate according to the embodiment of the present invention is the analytical method A, the total fluorine amount is quantified in the total fluorine amount quantification step. The total amount of fluorine and the amount of fluorine ions can be quantified by the total fluorine amount quantifying device for quantifying the amount of fluorine ions and the fluorine ion amount quantifying device for quantifying the amount of fluorine ions in the fluorine ion amount quantifying step. Further, if the total fluorine amount quantifying device and the fluorine ion amount quantifying device are connected to a calculation device for performing a step of calculating the amount of fluorine derived from tetrafluoroboric acid and a step of calculating the amount of tetrafluoroboric acid in the sample liquid, , The amount of tetrafluoroboric acid in the sample liquid can be calculated.

Therefore, one embodiment of the present invention includes a total fluorine amount quantifying device, a fluorine ion amount quantifying device, and an input unit for inputting a correction coefficient A, and the total fluorine amount output from the total fluorine amount quantifying device. Also included is a tetrafluoroboric acid analyzer, which includes an arithmetic device for calculating the amount of tetrafluoroboric acid in the sample liquid from the amount of fluorine ions output from the fluorine ion amount quantifying device and the correction coefficient A.

Here, the correction coefficient A, the total amount of fluorine, the amount of fluorine ions, and the amount of tetrafluoroboric acid in the sample liquid are as described in (I) above, and thus the description thereof will be omitted here.

An example of an analyzer in the case where the method for analyzing tetrafluoroboric acid is the analysis method A is a tetrafluoroboric acid analyzer including a total boron amount quantifier, a boron ion amount quantifier, and a calculation device. This will be described with reference to FIG. 1 shown.

The analyzer includes a total fluorine amount quantifier, a fluorine ion amount quantifier, and an input unit for inputting a correction coefficient A, and the total fluorine amount output from the total fluorine amount quantifier and the fluorine ion amount quantification. It is provided with a calculation device for calculating the amount of tetrafluoroboric acid in the sample liquid from the amount of fluorine ions output from the device and the correction coefficient A. That is, a total fluorine quantifying device is provided in place of the total boron amount quantifying device shown in FIG. 1, and a fluorine ion amount quantifying device is provided in place of the boron ion amount quantifying device shown in FIG. It is the same as the arithmetic unit described above in (III-1) except that the arithmetic unit includes an input unit for inputting the correction coefficient A.

The total fluorine amount quantifying device is a device capable of quantifying the total fluorine amount by a continuous flow analysis method (CFA) (hereinafter, referred to as a CFA total fluorine amount quantifying device). The CFA total fluorine amount quantifying device is provided with a thin tube through which a sample passes, and is provided with a sample introduction part, a distiller, a reaction part, and a detection part in this order with respect to the flow direction of the sample in the thin tube. The CFA total fluorine amount quantifying device further includes a coloring liquid introduction section between the distiller and the reaction section. It differs from the analyzer shown in FIG. 1 in that it is provided with a distiller instead of a heater and is not provided with a metal ion-containing liquid introduction unit. With this configuration, the total amount of fluorine in the sample liquid can be quantified by the distillation-lanthanum alizarin complexone absorptiometry method by continuous flow analysis (CFA).

The fluorine ion amount quantifying device is a device capable of measuring the fluorine ion amount by a continuous flow analysis method (CFA) (hereinafter, referred to as a CFA fluorine ion amount quantifying device). The CFA fluorine ion amount quantifying device is provided with a thin tube through which a sample passes, and is provided with a sample introduction part, a reaction part, and a detection part in this order with respect to the flow direction of the sample in the thin tube. The CFA fluorine ion amount quantifying device further includes a color-developing liquid introduction section between the sample introduction section and the reaction section in this order with respect to the flow direction of the sample in the capillary tube. That is, it is the same as the total fluorine amount quantifying device except that it does not have a distillation unit. With this configuration, the amount of fluorine ions in the sample liquid can be quantified by the lanthanum alizarin complexone absorptiometry method by continuous flow analysis (CFA).

Further, instead of the CFA total fluorine amount quantifying device, an device capable of quantifying the total fluorine amount by a flow injection analysis method (FIA) (hereinafter, referred to as a FIA total fluorine amount quantifying device) may be used. The FIA total fluorine amount quantifying device will be described with reference to FIG. 2 (a).

The FIA total fluorine amount quantifying device includes a thin tube through which the carrier liquid flows continuously, and has a carrier liquid introduction part, a reaction part, and a detection part in this order with respect to the flow direction of the carrier liquid in the thin tube. There is. The FIA total fluorine amount quantifying device further includes a sample introduction unit and a color-developing liquid introduction unit between the carrier liquid introduction unit and the reaction unit in this order with respect to the flow direction of the sample in the capillary tube. It differs from the total boron amount quantifying device shown in FIG. 2A in that it does not have a heater and a metal ion-containing liquid introduction unit. With this configuration, the total amount of fluorine in the sample liquid distilled by the distiller can be quantified by the lanthanum allizarin complexone absorptiometry method by the flow injection analysis method (FIA). When the FIA total fluorine amount quantifying device is used, since the FIA total fluorine amount quantifying device does not have a distiller, it is necessary to use the sample liquid distilled by the distiller.

Further, instead of the CFA fluorine ion amount quantifying device, an device capable of quantifying the fluorine ion amount by a flow injection analysis method (FIA) (hereinafter, referred to as a FIA fluorine ion amount quantifying device) may be used.

The FIA fluorine ion amount quantifying device includes a thin tube through which the carrier liquid flows continuously, and has a carrier liquid introduction part, a reaction part, and a detection part in this order with respect to the flow direction of the carrier liquid in the thin tube. There is. The FIA fluorine ion amount quantifying device further includes a sample introduction unit and a color-developing liquid introduction unit between the carrier liquid introduction unit and the reaction unit in this order with respect to the flow direction of the sample in the capillary tube. That is, the configuration of the FIA fluorine ion amount quantifying device is the same as the configuration of the FIA boron ion amount quantifying device shown in FIG. 2 (b). The amount of fluorine ions in the sample liquid can be quantified by the lanthanum alizarin complexone absorptiometry method by flow injection analysis (FIA).

Further, in the analyzer according to the embodiment of the present invention, only the CFA total fluorine amount quantifying device may be replaced with the FIA total fluorine amount quantifying device, and only the CFA fluorine ion amount quantifying device may be replaced with the FIA fluorine ion amount quantifying device. It may be replaced with a quantification device, or both the CFA total fluorine amount quantification device and the CFA fluorine ion amount quantification device may be replaced with the FIA type quantification device.

Further, as a total fluorine amount quantifying device and a fluorine ion amount quantifying device, a device that performs quantification by a flow analysis method has been described, but the total fluorine amount quantifying device and the fluorine ion amount quantifying device carry out quantification by a flow analysis method. The device is not limited to the device for performing quantification, and may be a device for performing quantification by the above-mentioned other method.

More preferably, at least one of the total fluorine amount quantifying device and the fluorine ion amount quantifying device is a flow analyzer.

The present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the claims, and the embodiments obtained by appropriately combining the technical means disclosed in the different embodiments. Is also included in the technical scope of the present invention.

Hereinafter, the present invention will be specifically described with reference to Examples, but the present invention is not limited to Examples.

[Calculation of correction coefficient A]
Fluoroboric acid reagent (manufactured by Wako Pure Chemical Industries, Ltd., product name: tetrafluoroboric acid) is added to pure water, and the final concentration of fluorine in tetrafluoroboric acid is 870 mg / L (that is, the final concentration of tetrafluoroboric acid). Was dissolved to 1005 mg / L) to prepare Sample 1. Further, the sample is prepared by dissolving the tetrafluoroboric acid reagent in pure water so that the final concentration of fluorine of tetrafluoroboric acid is 100 mg / L (that is, the final concentration of tetrafluoroboric acid is 115 mg / L). It was set to 2. The total amount of fluorine in Samples 1 and 2 was measured by the distillation-lantern alizarin complexone coloring CFA method specified in JIS K 0170-6 6.3.3, and the amount of fluorine ions in Samples 1 and 2 was JIS. It was measured by the lanthanum alizarin complexone coloring CFA method according to K 0170-6 6.3.3. The results are shown in Table 1.

In order to calculate the correction coefficient A shown in the following formula (3) based on the measured values of the total fluorine amount and the fluorine ion amount of the samples 1 and 2 in which only tetrafluoroboric acid is dissolved, it is shown in the following formula. The value of a was calculated. The results are shown in Table 2.

a = {(Amount of fluorine ions in the sample liquid after adding a standard solution containing only a known amount of tetrafluoroboric acid)-(Amount of fluorine ions in the sample liquid before adding the standard solution)} / ( Fluorine derived from tetrafluoroboric acid in the added standard solution) × 100… Formula (3)

The average value of the ratio of fluorine present as fluorine ions in the liquid to the total amount of fluorine in the tetrafluoroboric acid of the two samples was 30.5%. Next, the correction coefficient A was calculated according to the following formula.
Correction coefficient A = 100 / (100-30.5)
[Example 1]
Add the tetrafluoroboric acid reagent to pure water so that the final concentration of fluorine in tetrafluoroboric acid is 500 mg / L (that is, the final concentration of tetrafluoroboric acid is 578 mg / L), and the fluorine ion standard. Liquid (manufactured by Wako Pure Chemical Industries, Ltd., product name: fluoride ion standard solution (F ⁻ : 1,000)) so that the final concentration of fluorine ions becomes 500 mg / L, that is, 1000 mg as the total amount of fluorine. It was dissolved to be / L to prepare Sample 3.

The total amount of fluorine in sample 3 was measured by the lanthanum alizarin complexone coloring CFA method specified in JIS K 0170-6 6.3.3, and the amount of fluorine ions in sample 3 was JIS K 0170-6 6. It was measured by the lanthanum alizarin complexone coloring CFA method according to 3.3. The results are shown in Table 1.

Next, the amount of fluorine derived from tetrafluoroboric acid in the sample liquid is calculated by the following formula (1).
(Amount of fluorine derived from tetrafluoroboric acid in sample liquid) = {(total amount of fluorine)-(amount of fluorine ions)} × correction coefficient A ... Equation (1)
The amount of tetrafluoroboric acid in the sample liquid was calculated according to the following formula (4). The results are shown in Table 3.
(Amount of tetrafluoroboric acid in sample liquid) = (Amount of fluorine derived from tetrafluoroboric acid in sample liquid) × (Molecular weight of tetrafluoroboric acid 87.81) / (Element of fluorine in tetrafluoroboric acid) Quantity 76)… Equation (4)
As shown in Table 3, the calculated amount of tetrafluoroboric acid in the sample liquid was close to the amount of added tetrafluoroboric acid.

The same calculation was performed for samples 1 and 2, and the obtained results are shown in Table 3. For Samples 1 and 2, the calculated amount of tetrafluoroboric acid in the sample liquid was close to the amount of added tetrafluoroboric acid.

[Example 2]
Add the tetrafluoroboric acid reagent to pure water so that the final concentration of fluorine in tetrafluoroboric acid is 100 mg / L (that is, the final concentration of tetrafluoroboric acid is 115 mg / L), and the fluorine ion standard. The solution was dissolved so that the final concentration of fluorine ions was 100 mg / L, that is, the total amount of fluorine was 200 mg / L, and the solution was prepared as Sample 4. The total amount of fluorine and the amount of fluorine ions of Sample 4 were measured in the same manner as in Example 1. The results are shown in Table 1. Further, in the same manner as in Example 1, the amount of fluorine derived from tetrafluoroboric acid in the sample liquid and the amount of tetrafluoroboric acid in the sample liquid were calculated. The results are shown in Table 3.

As shown in Table 3, the calculated amount of tetrafluoroboric acid in the sample liquid was close to the amount of added tetrafluoroboric acid.

<Calculation of correction coefficient B>
The sample is prepared by dissolving the tetrafluoroboric acid reagent in pure water so that the final concentration of boron in tetrafluoroboric acid is 14.2 mg / L (that is, the final concentration of tetrafluoroboric acid is 115 mg / L). It was set to 5. The total amount of boron in Sample 5 was measured by the thermal decomposition-azomethine H CFA method, and the amount of boron ions was measured by the JIS K 0102 47.2 compliant azomethin H CFA method. The results are shown in Table 5.

Although the boron element does not exist as an ion by itself, the amount of boric acid present as an ion and measured by the azomethine HCFA method is taken as the amount of boron ion for convenience.

Boron ion standard solution (manufactured by Wako Pure Chemical Industries, Ltd., product name: boron standard solution (B1000)) without adding the tetrafluoroboric acid reagent to pure water, the final concentration of boron ions is 14.2 mg. It was dissolved to be / L to prepare sample 7. In the same manner as in Sample 5, the total amount of boron and the amount of boron ions in Sample 7 were measured. The results are shown in Table 4.

Sample 5 is a sample in which only tetrafluoroboric acid is dissolved, but boron ions were detected in the measurement by the azomethine HCFA method.

In order to calculate the correction coefficient B shown in the following formula (5) based on the measured values of the total boron amount and the boron ion amount of the sample 5 which is a sample in which only tetrafluoroboric acid is dissolved, the correction coefficient B shown in the following formula is calculated. The value was calculated. The results are shown in Table 5.

b = {(Amount of boron ions in the sample liquid after adding a standard solution containing only a known amount of tetrafluoroboric acid)-(Amount of boron ions in the sample liquid before adding the standard solution)} / ( Amount of boron derived from tetrafluoroboric acid in the added standard solution) × 100… Formula (5)

The ratio of boron present as boron ions in the liquid to the total amount of boron in the tetrafluoroboric acid of Sample 5 was 31.0%. Next, the correction coefficient B was calculated according to the following formula.
Correction coefficient B = 100 / (100-31.0)
The ratio of boron present as boron ion in the liquid to the total amount of boron of tetrafluoroboric acid is the ratio of fluorine present as fluorine ion in the liquid to the total amount of fluorine of tetrafluoroboric acid shown in Table 2. It was almost the same as (mean value 30.5%). It was suggested that when tetrafluoroboric acid is present as an aqueous solution, the bond between boron and fluorine may be separated and exist as an ion in about 30% of the molecules (tetrafluoroborate ion).

[Example 3]
The tetrafluoroboric acid reagent was added to pure water so that the final concentration of boron in tetrafluoroboric acid was 14.2 mg / L (that is, the final concentration of tetrafluoroboric acid was 115 mg / L), and the above. The boron ion standard solution was dissolved so that the final concentration of boron ions was 14.2 mg / L, that is, the total boron content was 28.4 mg / L, and the sample 6 was prepared. The total amount of boron and the amount of boron ions of Sample 6 were measured in the same manner as in Sample 5. The results are shown in Table 5.

Next, the amount of boron derived from tetrafluoroboric acid in the sample liquid is calculated by the following formula (2).
(Amount of boron derived from tetrafluoroboric acid in sample liquid) = {(total amount of boron)-(amount of boron ions)} × correction coefficient B ... Equation (2)
The amount of tetrafluoroboric acid in the sample liquid was calculated according to the following formula (6). The results are shown in Table 6.
(Amount of tetrafluoroboric acid in sample liquid) = (Amount of boron derived from tetrafluoroboric acid in sample liquid) × {(Molecular weight of tetrafluoroboric acid 87.81) / (Amount of boron in tetrafluoroboric acid) Molecular weight 10.81)… Equation (6)
As shown in Table 6, the calculated amount of tetrafluoroboric acid in the sample liquid was close to the amount of added tetrafluoroboric acid.

The same calculation was performed for sample 5, and the obtained results are shown in Table 6. For sample 5, the calculated amount of tetrafluoroboric acid in the sample liquid was close to the amount of added tetrafluoroboric acid.

Sample 2 and Sample 5 are samples containing the same amount of tetrafluoroboric acid. The content of tetrafluoroboric acid could be calculated both from the measurement of the total amount of fluorine and the amount of fluorine ions, and from the measurement of the total amount of boron and the amount of boron ions.

[Examples 4 to 8]
The total fluorine amount, fluorine ion amount, total boron amount, and boron ion amount of samples 8 to 12 of the actual waste liquid of the factory where the amount of tetrafluoroboric acid was unknown were measured in the same manner as in Examples 1 to 3. .. From the obtained measured values, the amount of fluorine derived from tetrafluoroboric acid, the amount of boron derived from tetrafluoroboric acid, and the amount of tetrafluoroboric acid were calculated in the same manner as in Examples 1 to 3. The results are shown in Tables 7 and 8.

The amount of tetrafluoroboric acid calculated from the measurement of the total amount of fluorine and the amount of fluorine ions and the amount of tetrafluoroboric acid calculated from the measurement of the total amount of boron and the amount of boron ions were almost close to each other.

[Reference Example 1]
Hexafluorosilicic acid reagent (manufactured by Wako Pure Chemical Industries, Ltd., product name: hexafluorosilicic acid) is added to pure water, and the final concentration of fluorine in hexafluorosilicic acid is 100 mg / L (that is, the final concentration of hexafluorosilicic acid). It was dissolved to a concentration of 126 mg / L) to prepare sample 13. Further, the hexafluorosilicic acid standard solution is added to pure water so that the final concentration of fluorine of hexafluorosilicic acid is 100 mg / L (that is, the final concentration of tetrafluoroboric acid is 126 mg / L), and the above. The fluorine ion standard solution was dissolved so that the final concentration of fluorine ions was 100 mg / L, that is, the total amount of fluorine was 200 mg / L, and the sample 14 was prepared. Further, the fluorine ion standard solution was dissolved in pure water so that the final concentration of fluorine ions was 100 mg / L to prepare sample 15.

The total amount of fluorine in Samples 13 to 15 was measured by the distillation-lantern alizarin complexone coloring CFA method specified in JIS K 0170-6 6.3.3, and the amount of fluorine ions in Samples 13 to 15 was JIS. It was measured by the lanthanum alizarin complexone coloring CFA method according to K 0170-6 6.3.3. The results are shown in Table 9.

As shown in Table 9, it was confirmed that when hexafluorosilicic acid was present in the solution, the fluorine of hexafluorosilicic acid was detected as substantially the total amount of ions.

INDUSTRIAL APPLICABILITY The present invention can be suitably used for process control and wastewater control of a glass manufacturing factory, waste treatment plant, and water quality control in a facility for purifying seawater into fresh water by RO membrane.

Claims (7)

An analytical method for quantifying tetrafluoroboric acid in a liquid containing tetrafluoroboric acid, which comprises the following (A) or (B).
(A) A step of quantifying fluorine in a sample liquid to determine the total amount of fluorine.
The process of quantifying the fluorine ions in the sample liquid to determine the amount of fluorine ions, and
Step of calculating the amount of fluorine derived from tetrafluoroboric acid in the sample liquid by the following formula (1) (amount of fluorine derived from tetrafluoroboric acid in the sample liquid) = {(total amount of fluorine)-(fluorine ion) Amount)} × Correction coefficient A ... Equation (1)
(In the formula (1), the correction coefficient A = 100 / (100-{(amount of fluorine ions in the sample liquid after adding a standard solution containing only a known amount of tetrafluoroboric acid)-(add the standard solution). The amount of fluorine ions in the sample liquid before the preparation)} / (the amount of fluorine derived from the tetrafluoroboric acid in the added standard liquid) × 100).
(B) A step of quantifying boron in a sample liquid to determine the total amount of boron.
A step of quantifying boron ions in a sample liquid to determine the amount of boron ions, and
A step of calculating the amount of boron derived from tetrafluoroboric acid in the sample liquid by the following formula (2).
(Amount of boron derived from tetrafluoroboric acid in sample liquid) = {(total amount of boron)-(amount of boron ions)} × correction coefficient B ... Equation (2)
(In the formula (2), the correction coefficient B = 100 / (100-{(amount of boron ions in the sample liquid after adding a standard solution containing only a known amount of tetrafluoroboric acid)-(add the standard solution). The amount of boron ions in the sample liquid before the preparation)} / (the amount of boron derived from tetrafluoroboric acid in the added standard liquid) × 100). Further, a step of calculating the amount of tetrafluoroboric acid in the sample liquid from the amount of fluorine derived from the amount of tetrafluoroboric acid in the sample liquid or the amount of boron derived from the amount of tetrafluoroboric acid in the sample liquid. The analysis method according to claim 1, which comprises. The analysis method according to claim 1 or 2, further comprising a step of determining the correction coefficient A or a step of determining the correction coefficient B. The total amount of fluorine is quantified by distillation-lantern alizaline complex absorptiometry, distillation-ion electrode method, or distillation-lantern alizarin complex absorptiometry by flow analysis, and the amount of fluorine ions is quantified by ion chromatography, ion electrode. The analysis method according to any one of claims 1 to 3, which is quantified by a method, a lanthanum alysine complex absorptiometry, or a lanthanum alysine complex absorptiometry by a flow analysis method. The total amount of boron is quantified by acid decomposition-ICP emission spectrometric analysis, acid decomposition-ICP mass spectrometry, or thermal decomposition flow analysis, and the amount of boron ions is determined by ion chromatography, azomethine H method, or flow analysis. The analysis method according to any one of claims 1 to 3, which is quantified by the azomethine H method according to the above. An analyzer for quantifying tetrafluoroboric acid in a liquid containing tetrafluoroboric acid, which comprises the following (C) or (D).
(C) A total fluorine amount quantifying device, a fluorine ion amount quantifying device, and an input unit for inputting a correction coefficient A are provided, and the total fluorine amount output from the total fluorine amount quantifying device and the fluorine ion amount quantifying device are output. An arithmetic device for calculating the amount of tetrafluoroboric acid in the sample liquid from the amount of fluorine ions and the correction coefficient A, where the correction coefficient A = 100 / (100-{(known amount of tetrafluoroboric acid) Amount of fluorine ions in the sample liquid after adding the standard solution containing only)-(Amount of fluorine ions in the sample liquid before adding the standard solution)} / (Tetrafluoroboric acid in the added standard solution The amount of fluorine derived from) × 100).
(D) A total boron amount quantifying device, a boron ion amount quantifying device, and an input unit for inputting a correction coefficient B are provided, and the total boron amount output from the total boron amount quantifying device and the boron ion amount quantifying device are output. An arithmetic device for calculating the amount of tetrafluoroboric acid in the sample liquid from the amount of boron ions and the correction coefficient B, where the correction coefficient B = 100 / (100-{(known amount of tetrafluoroboric acid) Amount of boron ions in the sample liquid after the addition of the standard solution containing only)-(Amount of boron ions in the sample liquid before the addition of the standard solution)} / (Tetrafluoroboric acid in the added standard solution) The amount of boron derived from) × 100). 6. Claim 6 that at least one of the total fluorine amount quantifying device and the fluorine ion amount quantifying device, or at least one of the total boron amount quantifying device and the boron ion amount quantifying device is a flow analyzer. The analyzer described in.

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