JP2016223836A - Analysis method for metal in high-salinity sample - Google Patents

Abstract

PROBLEM TO BE SOLVED: To remove or suppress influences of a coexisting element in an ICP emission spectrochemical analysis and to provide a simple quantitative analysis method for determining a dilution rate suitable in the ICP emission spectrochemical analysis.SOLUTION: An ICP emission spectrochemical analysis method for a measured element in a sample solution including amount of coexisting element enough to cause ionization interference in an ICP emission spectrochemical analysis includes the steps of: using a chelate resin to process the sample solution under an effective condition in capturing the measured element, allowing the chelate resin to capture the measured element and also removing the coexisting element without allowing the chelate resin to capture it; processing the chelate resin after capturing the measured element, under an effective condition in separating the measured element, and obtaining an eluate with the measured element eluted; and applying the ICP emission spectrochemical analysis to the measured element in the eluate. In a preferable embodiment, the method further includes a step of determining quantity of the measured element in the sample solution by a fluorescent X-ray analysis method using a paper filter dripping method, and determining a dilution rate of the sample solution to be provided for the ICP emission spectrochemical analysis, on the basis of the obtained quantitative value.SELECTED DRAWING: None

Description

  For the purpose of environmental monitoring and prevention of environmental pollution, it is very important to investigate the environment such as water quality, soil and air, and analyze the pollution status and whether or not it contains excessive substances that adversely affect health. The necessity is high. In addition, in a system that performs water treatment, accurately grasping the concentration of a substance contained in a treatment target is economically meaningful for efficient treatment.

  Trace metals in environmental analysis generally require high sensitivity, dynamic range, and simultaneous analysis of multiple elements, such as inductively coupled plasma emission spectrometry (hereinafter referred to as ICP emission spectroscopy) (Patent Documents 1 and 2). Applied to various samples. ICP emission spectroscopic analysis is an emission spectroscopic method using a high-frequency coupled plasma as a light source. A sample atomized by a nebulizer is introduced into a high-temperature argon plasma, and the light emitted by the excited element is dispersed with a spectrometer. In this method, qualitative analysis can be performed from the wavelength and quantitative analysis from the intensity.

  As an analysis method for trace metals, there is a fluorescent X-ray analysis method. X-ray fluorescence analysis is a highly versatile technique in that it can quickly analyze multiple elements simultaneously. However, when quantifying trace elements in a liquid sample, it is usually necessary to concentrate the liquid sample by some means. is there. As a technique for this purpose, a filter paper drip method has been developed in which a liquid sample is dropped onto a filter paper and dried to concentrate and retain the contained components (Patent Documents 3 to 6).

  On the other hand, it is proposed to use a chelating agent or a chelating resin when analyzing the concentration of heavy metal ions or rare earth metal ions, or when removing or recovering heavy metals from a solution such as industrial wastewater ( Patent Documents 7 and 8).

JP 2009-85943 JP 2008-309767 International Publication WO2005 / 012889 Japanese Patent Laid-Open No. 7-311131 JP 2002-296152 A JP 2009-222615 JP 2012-27006 A WO2010 / 098257 Publication

  In ICP emission spectroscopic analysis, if an element other than the element to be measured, such as a matrix component (alkali metal, alkaline earth metal, etc.) coexists in the sample solution to be measured, the coexisting element is also introduced into the plasma and ionized. Interact with each other, that is, cause ionization interference and change the emission intensity. Therefore, in order to analyze a very small amount of element to be measured with high sensitivity, it is necessary to eliminate or suppress the influence of the coexisting element.

  Furthermore, in the ICP emission spectroscopic analysis, it was necessary to repeat the sample dilution and the ICP emission spectroscopic analysis operation in order to keep the target element to be measured within the proper concentration level and to confirm the influence of the coexisting elements. Therefore, the whole analysis operation is very complicated and inefficient. It would be desirable to have a simple quantitative analysis method that can determine an appropriate dilution factor for ICP emission spectroscopic analysis.

The present invention provides the following.
[1] A method for ICP emission spectroscopic analysis of an element to be measured in a sample solution:
The sample solution contains an amount of coexisting elements that cause ionization interference during ICP emission spectroscopy;
Treating the sample solution with a chelate resin under conditions effective for capturing the element to be measured, allowing the element to be measured to be captured by the chelate resin, and removing the coexisting element without capturing it by the chelate resin;
Processing the chelate resin captured by the element to be measured under conditions effective for the separation of the element to be measured to obtain an eluate from which the element to be measured is eluted; and the element to be measured in the eluate is subjected to ICP emission spectroscopy. A method comprising the step of analyzing.
[2] The method according to 1, wherein the coexisting element is any one selected from the group consisting of alkali metals and alkaline earth metals.
[3] The method according to 2, wherein the coexisting element is any one selected from the group consisting of sodium, potassium, magnesium and calcium.
[4] The method according to any one of 1 to 3, wherein the element to be measured is any one selected from the group consisting of iron, nickel, copper, zinc, cadmium, lead, cobalt, and uranium.
[5] The method according to any one of 1 to 4, wherein the chelate resin is of iminodicarboxylic acid type or polyamine type.
[6] The method according to 5, wherein the chelate resin has ethylenediaminetriacetic acid and iminodiacetic acid as functional groups.
[7] The method according to any one of 1 to 6, wherein the effective conditions for capturing the element to be measured are acidic conditions.
[8] The method according to 7, wherein the acidic condition is pH 4.5 or more and less than 7.
[9] The method according to any one of 1 to 8, wherein the sample solution is pulp waste liquid, white liquor or green liquor.
[10] A method for ICP emission spectroscopic analysis of an element to be measured in a sample solution:
The sample solution contains an amount of coexisting elements that cause ionization interference during ICP emission spectroscopy;
A method comprising adding an ionization interference inhibitor to a sample solution and performing ICP emission spectroscopic analysis of an element to be measured in the sample solution in the presence of the ionization interference inhibitor.
[11] A step of quantifying an element to be measured in a sample solution by a fluorescent X-ray analysis method using a filter paper drip method, and determining a dilution rate of the sample solution to be subjected to ICP emission spectroscopic analysis based on the obtained quantitative value. The method according to any one of 1 to 10, further comprising:

Even when the sample solution contains an amount of coexisting elements that cause ionization interference during ICP emission spectroscopic analysis, it is possible to perform highly sensitive analysis in which the influence of the coexisting elements is suppressed or eliminated.
By the fluorescent X-ray analysis using the drip filter paper method, it is possible to easily determine the appropriate dilution factor of the sample solution for ICP emission spectroscopic analysis. Further, the combined use of this X-ray fluorescence analysis and ICP emission spectroscopic analysis can improve the analysis accuracy.

Effects of ionization interference inhibitors Comparison of Na concentration Elemental spectrum of X-ray fluorescence analysis Calibration curve for metal elements

  “Parts” and “%” represent ratios based on mass (parts by mass, mass%) unless otherwise specified. The numerical range “X to Y” includes values at both ends unless otherwise specified. “Any” (selected from the group consisting of ...) refers to any member included in the group, unless otherwise specified, and the number of members is not limited to one and may be plural. May be. “Analysis” includes qualitative and quantitative cases, unless otherwise specified.

The present invention provides an ICP emission spectroscopic analysis method for an element to be measured in a sample solution having the following characteristics:
The sample solution contains an amount of coexisting elements that causes ionization interference during ICP emission spectroscopic analysis.
-The following steps are included.
The sample solution is treated with a chelate resin under conditions effective for capturing the element to be measured, the element to be measured is captured by the chelate resin, and the coexisting element is removed without being captured by the chelate resin (step (1)) );
Processing the chelate resin that captures the element to be measured under conditions effective for the separation of the element to be measured to obtain an eluate from which the element to be measured is eluted (step (2)); and the measurement in the eluate A step of analyzing the element by ICP emission spectroscopy (step (3)).

[Sample solution to be measured]
The ICP emission spectroscopic analysis method of the present embodiment is suitable for analysis of various sample solutions containing an element to be measured and containing coexisting elements at a concentration high enough to cause ionization interference during ICP emission spectroscopic analysis.

<Element to be measured>
The element to be measured measured by the method of the present embodiment is not particularly limited as long as it can be captured by a chelate resin described later and can be eluted from the chelate resin under appropriate conditions. Note that “capture is possible” means that the capture rate exceeds 70%, preferably the capture rate exceeds 80%, and more preferably the capture rate exceeds 90%. Depending on the chelate resin used, examples of elements to be measured include iron, nickel, copper, zinc, cadmium, lead, aluminum, scandium, titanium, vanadium, manganese, cobalt, gallium, yttrium, zirconium, molybdenum, silver, Indium, tin, hafnium, tungsten, bismuth, lanthanum, cerium, praseodymium, neodymium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium, thorium and uranium. There are usually multiple elements to be measured, which can be analyzed simultaneously.

  Examples of preferable elements to be measured are any selected from the group consisting of iron, nickel, copper, zinc, cadmium, lead, cobalt, and uranium. In one preferred embodiment, iron, nickel, copper, zinc, cadmium and lead are analyzed simultaneously as elements to be measured.

  The concentration of the element to be measured in the ICP emission spectroscopic analysis can be appropriately set by those skilled in the art in consideration of the characteristics of the apparatus used and the range of the calibration curve. The lower limit value of the concentration of the element to be measured is, for example, 1 μg / L although it depends on the type of the element to be measured. The upper limit value of the concentration of the element to be measured is, for example, 1000 μg / L, preferably 600 μg / L, although it depends on the type of element to be measured. The sample solution can be diluted as necessary and provided to an ICP emission spectroscopic analyzer.

<Coexisting elements>
The coexisting element means an element other than the element to be measured contained in the sample solution, and is not particularly limited as long as it is not captured by the chelate resin described later. The term “not captured” means that the capture rate is 10% or less, preferably 5% or less, and more preferably 1% or less. Depending on the chelate resin used, examples of coexisting elements include alkali metals and alkaline earth metals. Magnesium is not included in the narrowly defined alkaline earth metal, but is included in the present application.

  Whatever the element to be measured, any preferred coexisting element is any selected from the group consisting of sodium, potassium, magnesium and calcium. In one preferred embodiment, the coexisting elements are sodium, potassium, magnesium and calcium, regardless of the element to be measured.

  In the method of this embodiment, the sample solution to be measured contains coexisting elements in an amount that causes ionization interference in the ICP emission spectroscopic analysis. The concentration of coexisting elements that cause ionization interference during ICP emission spectroscopic analysis depends on the type of element to be measured and the type of coexisting elements. For example, in the case of sodium, ionization interference occurs when the concentration is 600 ppm or more. In the case of seawater, the seawater contains about 35,000 ppm of sodium, which clearly causes ionization interference.

  In the method of this embodiment, by using the chelate resin described later, the coexisting elements can be sufficiently removed from the sample solution prior to the ICP emission spectroscopic analysis. May be included. For example, in the case of sodium, it may be contained at 200 ppm or more, 2,000 ppm or more, or 20,000 ppm or more. Moreover, as long as it is potassium, it may be contained 70 ppm or more, may be contained 700 ppm or more, and may be contained 7,000 ppm or more. Further, calcium may be contained at 20 ppm or more, may be contained at 200 ppm or more, and may be contained at 300 ppm or more. Further, in the case of magnesium, it may be contained at 30 ppm or more, may be contained at 300 ppm or more, and may be contained at 1000 ppm or more. Since the coexisting elements are not captured by the chelate resin, the upper limit of the concentration of the coexisting elements that may be contained in the sample solution is not particularly limited.

<Sample solution>
Specific examples of sample solutions containing coexisting elements in amounts that cause ionization interference in ICP emission spectroscopic analysis include seawater and various liquids generated in processes such as pulp fiber production, such as pulp waste liquid, green liquid, white liquid, and environmental processes. It is water.

Below, the process for producing pulp fibers as paper materials from wood chips will be outlined, and pulp waste liquid, green liquor, white liquor, environmental process water, etc. will be described.
The cooking chemical used in the kraft pulp manufacturing process is an alkaline aqueous solution containing sodium hydroxide and sodium sulfide, and is generally called white liquor. Using this white liquor, the wood chips are cooked under predetermined conditions. Pulp waste liquor (black liquor) generated after being separated from pulp after kraft cooking is composed of organic components such as lignin generated during cooking and inorganic components such as sodium salts. The black liquor is concentrated and then used as fuel for the chemical recovery boiler. The inorganic component remaining after combustion in the boiler is called smelt and is dissolved in a weak liquid which is a dilute alkaline aqueous solution to form a green liquid. This green liquor is converted into a white liquor in the alkali recovery step and used again as a cooking chemical. In the kraft pulp manufacturing process, the recovered inorganic components are repeatedly circulated, so that chlorine and potassium contained in the raw material wood chips and the like are concentrated. Since it causes corrosion and other troubles, it is necessary to remove a certain ratio of chlorine and potassium from boiler collection ash and the like. Boiler collection ash is fly ash collected by an electric dust collector installed in the flue of the recovery boiler, and contains sodium sulfate and sodium carbonate as main components. Methods for removing chlorine and potassium include dissolving sodium chloride and potassium sulfate in boiler collection ash in water, then separating and recovering solids (sodium sulfate) in the slurry, and dissolving boiler collection ash in water There is a method of cooling the dissolved slurry and separating (filtering) the sodium recrystallized by cooling from the dissolved slurry. The recovered sodium content is made solid by a dehydrator and supplied to dilute black liquor. Chlorine and potassium are dissolved in water and discharged as environmental process water (decalcified waste water).
In the method of this embodiment, various liquids generated in the process of producing such pulp fibers can be measured.

[Process (1)]
In step (1), the sample solution is treated with a chelate resin under conditions effective for capturing the element to be measured, the element to be measured is captured by the chelate resin, and the coexisting elements are removed without being captured by the chelate resin. .

<Chelate resin>
The chelate resin is a base resin in which a functional group that forms a chelate (complex) with a metal ion is introduced, and the metal ion can be captured by forming a chelate. As the functional group for forming a chelate, one containing two or more electron donating elements such as N, S, O, and P is used. Examples of the chelate resin include NO type, SN type, NN type, and OO type, but are not limited as long as the target element to be measured can be captured. As the chelating resin, an iminodicarboxylic acid type or a polyamine type is widely used, and in this embodiment, it can be used according to the element to be measured.

  Examples of preferable functional groups of the chelate resin are those having ethylenediaminetriacetic acid and iminodiacetic acid as functional groups, although depending on the sample solution and the type of the element to be measured.

  The base resin portion of the chelate resin can be selected according to the properties of the sample solution. For example, when an aqueous sample solution is used, it is preferably hydrophilic. Specific examples of the hydrophilic base resin include hydrophilic methacrylate.

  In one preferred embodiment, the chelate resin has hydrophilic methacrylate as a base resin and has ethylenediaminetriacetic acid and iminodiacetic acid as functional groups.

  The chelate resin is preferably in a form packed in a column. This is because the element to be measured can be easily captured by passing the liquid through the column. As an example of a commercial product of a chelate resin with hydrophilic methacrylate as a base resin and having ethylenediaminetriacetic acid and iminodiacetic acid as functional groups, the solid phase extraction column NOBIAS CHELATE-PA1 (Hitachi High-Technologies Corporation) Manufactured).

<Effective conditions for capturing elements to be measured>
The sample solution is treated with a chelate resin under conditions effective for capturing the element to be measured. An example of an effective condition for capturing the element to be measured is an acidic condition. The acidic condition is, for example, pH 4.5 or more and less than 7, preferably pH 5.0 or more and less than 6.5, and more preferably pH 5.5 or more and less than 6.0. This is because, within this range, iron, nickel, copper, zinc, cadmium and lead can be sufficiently captured, and the recovery rate described later for iron, nickel, copper, zinc, cadmium and lead is 80% by mass or more.

  Those skilled in the art can appropriately adjust the pH using an appropriate acid or alkali. The acid or alkali is preferably one that does not affect the ions of the element to be measured in the subsequent ICP emission spectroscopic analysis, that is, has no ionization interference. Specific examples of the acid or alkali that can be used are any of ammonium acetate, nitric acid, and ammonia, regardless of the element to be measured.

  In the step (1), the chelate resin captures the element to be measured, while the coexisting element is not captured by the chelate resin. When a chelate resin having a form packed in a column is used, the element to be measured is captured by passing the sample solution through the column, while the coexisting element passes through the column and is removed. After passing the sample solution, the column can be washed with an appropriate solution such as pure water to further sufficiently remove the coexisting elements.

[Process (2)]
In step (2), the chelate resin that has captured the element to be measured is treated under conditions effective for the separation of the element to be measured to obtain an eluate from which the element to be measured has been eluted.

<Effective conditions for separation of elements to be measured>
As conditions effective for separation of the element to be measured, various conditions under which the element to be measured is eluted can be used. Although depending on the chelate resin used and the element to be measured, an example of an effective condition for separating the element to be measured is to set the pH to 5.5, preferably to 5.0, and more preferably to pH 4.5. It is to be. Within this range, iron, nickel, copper, zinc, cadmium and lead can be sufficiently eluted, and the recovery rate for iron, nickel, copper, zinc, cadmium and lead can be 80% by mass or more. . The strong acid that can be used is preferably one that does not affect the ions of the element to be measured in the subsequent ICP emission spectroscopic analysis, that is, has no ionization interference. A specific example of a strong acid that can be used is nitric acid. The recovery rate (%) of the element to be measured is a value obtained by (amount of element to be measured eluted from chelate resin) / (amount of element to be measured contained in sample solution) × 100.

  When a chelate resin packed in a column is used, elution can be performed by passing a strong acid solution through the column to make the conditions effective for the separation of the element to be measured. Those skilled in the art can appropriately determine the flow rate and the flow rate.

  In the step (2), the element to be measured can be concentrated by appropriately adjusting the amount of the strong acid solution used to make the condition effective for the separation of the element to be measured.

[Process (3)]
In step (3), the eluate is used in an ICP emission spectroscopic analyzer. There are two types of ICP emission spectroscopic analyzers, a sequential type and a multi-channel type, and any of them can be used. The measurement includes axial observation and lateral observation, but axial observation is preferable from the viewpoint of good sensitivity. In general, in the axial observation, the influence of coexisting elements is large, but in this embodiment, the influence of coexisting elements is suppressed or eliminated.

[Others]
According to the study by the present inventors, when the sample solution contains an amount of coexisting elements that cause ionization interference in ICP emission spectroscopic analysis, the effect of coexisting elements can be suppressed or eliminated by using an appropriate ionization interference inhibitor. Can also be resolved. That is, one of the embodiments of the present invention is an ICP emission spectroscopic analysis method for an element to be measured in a sample solution having the following characteristics.
The sample solution contains an amount of coexisting elements that causes ionization interference during ICP emission spectroscopic analysis.
-Including the following steps.
A step of adding an ionization interference inhibitor to the sample solution and performing ICP emission spectroscopic analysis of the element to be measured in the sample solution in the presence of the ionization interference inhibitor.

  The element added as the ionization interference suppressor is an element different from the non-measurement element and has a relatively low ionization potential. Preferably, it is an element having an ionization potential equal to or lower than that of sodium and potassium. This is because an element having a low ionization potential is easily ionized when introduced into plasma and ionization interference is strongly generated, so that the emission intensity is further increased and the influence of coexisting elements can be further suppressed. Further, when the ionization potential of the element added as an ionization interference inhibitor is 5.14 eV of Na or less than 4.34 eV of Na, the influence of the coexisting elements can be more reliably suppressed. Examples of elements having a relatively low ionization potential include lithium, sodium, potassium, rubidium, cesium, francium, calcium, strontium, barium, and radium. One particularly preferred example is cesium. This is because the ionization potential is as small as 3.89 eV. When cesium is added as an ionization interference inhibitor to a sample solution for ICP measurement, it can be used as an aqueous solution of cesium chloride (CsCl).

  The concentration of the additive element is not particularly limited as long as ionization interference due to the coexisting elements is sufficiently suppressed and analysis of the non-measurement element can be appropriately performed. It can be added so that the concentration is 0.5 times or more of the coexisting element concentration. Specifically, when CsCl is used as the ionization interference inhibitor, CsCl can be added so that it is 0.5% by mass or more in the sample solution, and is preferably added so that it is 0.75% by mass or more. Preferably, it adds so that it may become 1 mass% or more. The upper limit value is not particularly limited, but can be, for example, 3% by mass or less, 2% by mass or less, or 1.5% by mass in consideration of economy and the like.

  In the ICP emission spectroscopic analysis, the present inventors also need to repeat the sample dilution and the ICP emission spectroscopic analysis operation in order to keep the target element to be measured within an appropriate concentration level and confirm the influence of coexisting elements. In view of this, a simple fluorescent X-ray analysis method using a filter paper drip method has also been developed. That is, one of the embodiments of the present invention is a sample that is subjected to ICP emission spectroscopic analysis based on the obtained quantitative value by quantifying the element to be measured in the sample solution by a fluorescent X-ray analysis method using a filter paper drip method. ICP emission spectral analysis further comprising the step of determining the dilution factor of the solution.

Regarding the filter paper drip method, the above-mentioned patent documents 3 to 6 can be referred to. In the fluorescent X-ray analysis in this embodiment, an existing filter paper drip method for measuring a trace amount of elements can be applied. In order to analyze a trace amount of non-measuring elements, it is preferable to use a filter paper from which impurities are excluded. Examples of this include Ultracarry (registered trademark) light manufactured by Rigaku Corporation. In the fluorescent X-ray analysis, it is preferable to use an aluminum sample holder, and it is preferable to use a sealed system in which scattered radiation does not enter from the surroundings.
According to the study by the present inventors, there is a sufficient correlation between the simple fluorescent X-ray analysis method using the filter paper drip method and the ICP emission spectroscopic analysis method. Therefore, the combined use of a simple fluorescent X-ray analysis method using a filter paper drip method and an ICP emission spectroscopic analysis method also has an advantage that the analysis can be double-checked. The combined use facilitates the discovery of operation mistakes and can be expected to obtain more accurate analysis results.

[Example 1]
Simulated seawater was prepared with ultrapure water so that the final concentration of sodium chloride (special grade reagent manufactured by Kanto Chemical) was 3% by mass (hereinafter referred to as “sample”). This sample and the ICP standard solution were mixed at a predetermined ratio (hereinafter referred to as “analytical sample”). Further, Na, Mg, K, and Ca (standard solution for atomic absorption analysis manufactured by Kanto Chemical Co., Ltd., 1000 mg / l) were added to the analysis sample as necessary. Next, the analytical sample was processed by the following procedure using a solid phase extraction column NOBIAS CHELATE-PA1 (Hitachi High-Tech Fielding Co., Ltd.). After 10 ml of acetone was added to the column (size: 78 mm (length) x φ15 mm (diameter), packing amount 240 mg) and swollen, the column was washed in the order of 3 mol / l nitric acid 10 ml and ultrapure water 20 ml, 0.1 mol / l l 10 ml of ammonium acetate was passed through.

  The sample for analysis was prepared with ultrapure water so that the final concentration of the metal element was 100 μg / l. Either ammonium acetate, nitric acid, or ammonia was added to the analytical sample to adjust the pH to 5.6, and then the analytical sample was passed through the column. After passing the analytical sample through the column, ultrapure water was passed through the column to remove components that were not adsorbed on the column. Next, 2 ml of 3 mol / l nitric acid was passed through the column to elute the components adsorbed on the column. The liquid was passed by natural dropping at a rate of 4 to 6 ml / min. The eluted aqueous solution (hereinafter referred to as “eluent”) was made up to 5 ml with ultrapure water to obtain a 10-fold concentrated liquid (hereinafter referred to as “column-treated sample”). The concentration of the metal component contained in this column-treated sample was measured using a spectro / axial observation ICP emission spectroscopic analyzer CIROS-120. The water used in this study was water purified by Merck Millipore Milli-Q Integral (specific resistance 18.2 MΩcm or more). Table 1 shows the analysis results of the metal components.

[Example 2]
Seawater (collected in Koto-ku, Tokyo. Na 9,400ppm, K 330ppm, Ca 340ppm, Mg 1120ppm) was used as a sample. Except that, all tests were performed in the same manner as in Example 1. Table 1 shows the analysis results of the metal components.

Example 3
Environmental process water (Na 50,689 ppm, K 25,542 ppm, Ca 218 ppm, Mg 32 ppm) was used as a sample. Except that, all tests were performed in the same manner as in Example 1. Table 1 shows the analysis results of the metal components.

Example 4
Pulp waste liquor was used as a sample. Except that, all tests were performed in the same manner as in Example 1. Table 1 shows the analysis results of the metal components.

Example 5
White liquor was used as a sample (Na 79,700 ppm, K 7,840 ppm, Ca 20 ppm). Except that, all tests were performed in the same manner as in Example 1. Table 1 shows the analysis results of the metal components.

Example 6
Green liquor (Na 87,000 ppm, K 7,820 ppm, Ca 23 ppm) was used as a sample. However, in Example 1, the ICP standard solution was added to the column-treated sample such that Cd 6 μg / l, Ni 20 μg / l, Pb 20 μg / l, Cu 200 μg / l, Zn 200 μg / l, Fe 600 μg / l. Added. Except that, all tests were performed in the same manner as in Example 1. Table 1 shows the analysis results of the metal components.

[Comparative Example 1]
In Example 1, all the samples for analysis were tested in the same manner as in Example 1 except that they were not treated with the solid phase extraction column NOBIAS CHELATE-PA1. As a result of analysis using an ICP emission spectroscopic analyzer, no metal component could be detected.

[Comparative Example 2]
In Example 2, all the samples for analysis were tested in the same manner as in Example 2 except that they were not treated with the solid phase extraction column NOBIAS CHELATE-PA1. As a result of analysis using an ICP emission spectroscopic analyzer, no metal component could be detected.

[Comparative Example 3]
In Example 3, all the samples for analysis were tested in the same manner as in Example 3 except that they were not treated with the solid phase extraction column NOBIAS CHELATE-PA1. As a result of analysis using an ICP emission spectroscopic analyzer, no metal component could be detected.

[Comparative Example 4]
In Example 4, all the samples for analysis were tested in the same manner as in Example 4 except that they were not treated with the solid phase extraction column NOBIAS CHELATE-PA1. As a result of analysis using an ICP emission spectroscopic analyzer, no metal component could be detected.

[Comparative Example 5]
In Example 5, all the samples for analysis were tested in the same manner as in Example 5 except that they were not treated with the solid phase extraction column NOBIAS CHELATE-PA1. As a result of analysis using an ICP emission spectroscopic analyzer, no metal component could be detected.

[Comparative Example 6]
In Example 6, all the samples for analysis were tested in the same manner as in Example 6 except that they were not treated with the solid phase extraction column NOBIAS CHELATE-PA1. As a result of analysis using an ICP emission spectroscopic analyzer, no metal component could be detected.

  Based on the above results, solid phase extraction columns efficiently remove undesired impurities (alkali metals, alkaline earth metals) and efficiently target metal elements (Fe, Ni, Cu, Zn, Cd, Pb). (The recovery rate of each metal element was 100 ± 5%). Pretreatment of the analytical sample with a solid phase extraction column has made it possible to perform metal element analysis with high accuracy by ICP emission spectroscopy.

Example 7
The test was conducted in the same manner as in Example 1 using ultrapure water as a sample. Here, a standard solution for ICP was added to the sample so that each concentration of Fe, Ni, Cu, Zn, Cd, and Pb was 100 μg / l. In Example 1, any one of ammonium acetate, nitric acid, and ammonia is added to the analytical sample to adjust the pH to 1.5, 2.5, 3.5, 4.5, 5.5, 6.5, 7.5, 8.5, and 9.5, and then the analytical sample is placed in the column. The liquid was passed. All other operations were tested in the same manner as in Example 1. Table 2 shows the analysis results of the metal components.

Example 8
It tested by the method similar to Example 7 using seawater as a sample. Table 3 shows the analysis results of the metal components.

[Reference Example 1: Method of using ionization interference inhibitor]
(1) Experimental Method In ICP emission spectroscopic analysis, the emission spectrum in an environmental sample is generally known as a comparatively easy analysis method with few extremely difficult spectral interferences. However, when the alkali metal (Na, K) in the high salt concentration was confirmed by the standard addition method, a phenomenon that the analytical value was reduced to about 80% of the actual amount was confirmed. As a result of detailed investigation and examination, the cause of ionization interference was found out of interference and interference by coexisting elements. As a test for reproducing ionization interference in a high salt sample, a sample having a K concentration of 0 to 10,000 mg / l was prepared for an Na concentration of 5 mg / l, and the effect of the ionization interference inhibitor was examined. Metal elemental analysis was performed using a spectro / axial observation ICP emission spectrometer CIROS-120.

  As a result of detailed examination of the reproduction test of ionization interference, alkaline earth metals such as metal elements, Ca and Mg had a small effect on the recovery rate, but alkali metals such as Na and K had an effect on the recovery rate. I understood that. Among the measurement conditions of ICP emission spectroscopic analysis, Na wavelength was 588.995 nm and K was 766.490 nm. When ionization energy was examined to examine a method for suppressing ionization interference, Na was 5.14 eV, K was 4.34 eV, and Cs was 3.89 eV, which was the most easily ionized element.

  As an examination of an ionization interference inhibitor, 0-2 mass% CsCl was added and measured. Although interference could not be suppressed with a small amount, it was good when 1% by mass of CsCl was added, and the effect was not changed even when more was added.

The results are shown in FIGS.
In the system in which the ionization interference inhibitor was not added, when the K concentration was 1000 mg / l or more with respect to the Na concentration of 5 mg / l, a large warp occurred on the graph (FIG. 1). On the other hand, in the system to which the ionization interference inhibitor was added, the Na concentration was 5 mg / l, and even when the K concentration increased, no significant warping occurred, and an appropriate concentration was observed.

  For confirmation, several samples of samples with similar ionization interference were analyzed, and the analysis value by the ion chromatograph method was compared with the analysis value by the ICP method without adding an ionization interference inhibitor, and the correlation was poor. (FIG. 2, plot of Δ). However, the analysis value by the ICP method to which 1% by mass of CsCl was added correlated well with the analysis value by the ion chromatography method (Fig. 2, ◯ plot). In addition, the effect of the ionization interference inhibitor was similarly confirmed also about the Na density | concentration in K solution.

[Reference Example 2: Infusion filter paper-X-ray fluorescence analysis]
The fluorescent X-ray analysis method is a highly versatile technique in that simultaneous multi-element analysis can be performed quickly, but some concentration treatment is required when quantifying trace elements in an aqueous solution. In addition, the high salt sample requires an appropriate dilution factor for measuring ICP emission spectroscopic analysis, and when it is large, it is necessary to prepare 5 to 6 diluted samples per sample, which is complicated. Since a quick and simple elemental analysis method is required, it was examined.

  The apparatus used was a wavelength dispersive X-ray fluorescence analyzer (Spectris PW2404) under the condition that one element can be measured for 10 seconds and all elements from Be (4) to U (92) can be measured in 9 minutes. In this analysis method, a calibration curve is prepared in advance, and the concentration can be calculated by inputting the measured X-ray intensity of the element into a spreadsheet. The calibration curve for Fe, Ni, Cu, Zn, Cd, and Pb (hereinafter referred to as metal elements) uses SPEX XSTC622B multi-element mixed standard solution (each element 10mg / l), Na, Mg, K, Ca The standard curve for atomic absorption (1000 mg / l) manufactured by Kanto Chemical Co., Ltd. was used for the calibration curve (hereinafter referred to as “matrix component”).

  In the pretreatment, 500 μl of the sample liquid was dropped with a micropipette onto Ultracarry (registered trademark) light (measured diameter: φ18 mm, material: ring / PET, film / PP, filter paper / cellulose) manufactured by Rigaku Corporation, and then dried. Using a sample holder made of aluminum, a fluorescent X-ray analysis was performed using a polyethylene cup so as to be a closed system in which scattered radiation does not enter from around.

  A calibration curve (0 to 10 mg / l) of a metal element using an ultra carry light-fluorescence X-ray analysis method was prepared. FIG. 3 shows an example of a fluorescent X-ray spectrum at a metal element concentration of 10 mg / l. FIG. 4 shows a calibration curve for Pb. The calibration curve of the metal element showed a good linear relationship, and the correlation coefficient was 1.000. Also, a good linear relationship was obtained for the calibration curve of the matrix component. Compare analytical values of fluorescent X-ray analysis and ICP emission spectroscopic analysis of metal elements 0, 0.1, 1, 5, and 10 mg / l in the calibration curve range (0 to 10 mg / l) prepared by X-ray fluorescence analysis As a result, it was confirmed that the correlation was high.

  From the above, metal elements and matrix components can be quickly and easily quantitatively analyzed by X-ray fluorescence analysis using ultra carry light, and a method that can estimate the dilution factor, metal element concentration, and matrix component concentration is available. It has been established. In addition, ICP emission spectroscopic analysis is quick and more accurate, and ICP emission spectroscopic analysis and X-ray fluorescence analysis can be double-checked, so it can be expected to prevent mistakes in advance.

〔Brief Summary〕
-This study has been difficult until now by examining solid-phase extraction columns-ICP emission spectroscopy, which can efficiently remove matrix components (alkali metals and alkaline earth metals) and concentrate target metal elements. As a result, the metal element (Fe, Ni, Cu, Zn, Cd, Pb) recovery rate was 100 ± 2%, and good results were obtained.
・ Although ionization interference due to alkali metals (Na, K) occurred in ICP emission spectroscopic analysis, it was improved by investigating ionization interference inhibitors, and showed high correlation with other analysis methods. In addition, the simplified X-ray fluorescence analysis method using the drip filter paper method has become possible, so that a quick and accurate dilution ratio can be grasped. Furthermore, this simple analysis method can double check with the ICP emission spectroscopic analysis method, improving the analysis accuracy.
The combined analysis by solid phase extraction column-ICP emission spectroscopic analysis and drip filter paper-fluorescence X-ray analysis is not limited to high salt concentration samples, and is considered to have a very wide range of applicable fields.

Claims (11)

An ICP emission spectroscopic analysis method for an element to be measured in a sample solution comprising:
The sample solution contains an amount of coexisting elements that cause ionization interference during ICP emission spectroscopy;
Treating the sample solution with a chelate resin under conditions effective for capturing the element to be measured, allowing the element to be measured to be captured by the chelate resin, and removing the coexisting element without capturing it by the chelate resin;
A process in which the chelate resin captured by the element to be measured is treated under conditions effective for separation of the element to be measured to obtain an eluate from which the element to be measured is eluted; and the element to be measured in the eluate is subjected to ICP emission. A method comprising the step of spectroscopic analysis. The method according to claim 1, wherein the coexisting element is any selected from the group consisting of alkali metals and alkaline earth metals. The method according to claim 2, wherein the coexisting element is any one selected from the group consisting of sodium, potassium, magnesium and calcium. The method according to any one of claims 1 to 3, wherein the element to be measured is any one selected from the group consisting of iron, nickel, copper, zinc, cadmium, lead, cobalt, and uranium. The method according to any one of claims 1 to 4, wherein the chelate resin is of iminodicarboxylic acid type or polyamine type. The method according to claim 5, wherein the chelate resin has ethylenediaminetriacetic acid and iminodiacetic acid as functional groups. The method according to claim 1, wherein the effective condition for capturing the element to be measured is an acidic condition. The method according to claim 7, wherein the acidic condition is pH 4.5 or more and less than 7. The method according to any one of claims 1 to 8, wherein the sample solution is pulp waste liquid, white liquor or green liquor. An ICP emission spectroscopic analysis method for an element to be measured in a sample solution comprising:
The sample solution contains an amount of coexisting elements that cause ionization interference during ICP emission spectroscopy;
A method comprising adding an ionization interference inhibitor to a sample solution and performing ICP emission spectroscopic analysis of an element to be measured in the sample solution in the presence of the ionization interference inhibitor. Further comprising the step of quantifying the element to be measured in the sample solution by fluorescent X-ray analysis using a filter paper drip method, and determining the dilution rate of the sample solution to be subjected to ICP emission spectrometry based on the obtained quantitative value; The method according to claim 1.