KR-102962538-B1 - Analysis method for metal impurity content

KR102962538B1KR 102962538 B1KR102962538 B1KR 102962538B1KR-102962538-B1

Abstract

A method for more accurately analyzing the content of metal impurities in a liquid (ultrapure water) containing low concentrations of metal impurities comprises a passing step of passing the liquid through an ion exchanger, an elution step of recovering metal impurities captured in the ion exchanger by eluting them with an eluent, and a measurement step of analyzing the eluent containing the eluted metal impurities to measure the content of metal impurities in the eluent, wherein the ion exchanger is characterized by using a plurality of ion exchangers of the same ion type (13A, 13B) connected in series, and the volume per unit of the porous ion exchanger is 0.5 to 5.0 ml, and the differential pressure coefficient is 0.01 MPa/LV/m or less.

Inventors

츠타노 쿄헤이

Assignees

오르가노 코포레이션

Dates

Publication Date: 20260508
Application Date: 20211013
Priority Date: 20201112

Claims (12)

As a method for analyzing the content of metal impurities in a liquid, A passing step of passing the above liquid through an ion exchanger; An elution step of recovering metal impurities captured in the ion exchanger by eluting them with an eluent; and A measurement step of analyzing an eluent containing eluted metal impurities and measuring the content of metal impurities in the eluent. Includes, The above ion exchanger is used by connecting two or more units of the same ion type in series, and The volume per unit of the above ion exchanger is 0.5 to 5.0 ml, and the differential pressure coefficient per unit is 0.01 MPa/LV/m or less, and A method for analyzing the content of metal impurities in a liquid, wherein the elution step and the measurement step are performed sequentially from the top for each unit of the ion exchanger, and when the content of metal impurities in the liquid measured in the measurement step becomes less than a quantitative lower limit, the total amount of the content of metal impurities in the liquid up to the point where it becomes less than the quantitative lower limit is defined as the content of metal impurities in the liquid.
In paragraph 1, A method for analyzing the content of metal impurities in a liquid, wherein the concentration of metal impurities to be analyzed in the liquid passed through the ion exchanger is less than 1 ng/L, based on a single metal element.
In paragraph 1 or 2, A method for analyzing the content of metal impurities in a liquid, wherein the above ion exchanger is a monolithic organic porous ion exchanger.
In paragraph 1 or 2, A method for analyzing the content of metal impurities in a liquid, wherein the number of units of the above-mentioned ion exchanger is the minimum number such that the content of metal impurities analyzed based on the last ion exchanger is less than the lower limit of the quantification.
In paragraph 1 or 2, A method for analyzing the content of metal impurities in a liquid, wherein if the content of metal impurities in the liquid measured in the above measurement step does not reach a quantitative lower limit value at the lowest ion exchanger, additional units of ion exchangers of the same ion type are connected in series downstream of the lowest ion exchanger, and the above liquid passage step, the above elution step, and the above measurement step are performed for every unit connected, and the total amount of the content of metal impurities in the liquid from the point at which the content of metal impurities in the liquid measured in the above measurement step falls below the quantitative lower limit value until it falls below the quantitative lower limit value is defined as the content of metal impurities in the liquid.
In paragraph 1 or 2, In the above-mentioned liquid passage step, a first ion exchanger and a second ion exchanger connected in parallel are used as the ion exchanger, and The above first ion exchanger is used by connecting two or more units of the first ion type ion exchanger in series, and A method for analyzing the content of metal impurities in a liquid, wherein the above-mentioned second ion exchanger is used by connecting two or more units of the second ion type ion exchanger in series.
In paragraph 1 or 2, A method for analyzing the content of metal impurities in a liquid, wherein in the above-mentioned liquid passing step, the ion exchanger is used by connecting a first ion exchanger containing a first ion type and a second ion exchanger containing a second ion type in series, and at least one of the first ion exchanger and the second ion exchanger is used by connecting two or more units of the same ion type in series.
In paragraph 1 or 2, A method for analyzing the content of metal impurities in a liquid, wherein the ion exchanger is a monolithic organic porous ion exchanger, and the ion exchange capacity per volume of the monolithic organic porous ion exchanger is 0.1 to 1.0 mg equivalent/mL (water-wet state) or 0.2 to 1.0 mg equivalent/mL (water-wet state).
In paragraph 1 or 2, A method for analyzing the content of metal impurities in a liquid, wherein the metal impurities to be analyzed are one or more of the elements Li, Be, B, Na, Mg, Al, K, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, As, Sr, Zr, Mo, Pd, Ag, Cd, Sn, Ba, W, Au, and Pb.
A measuring device used in the analysis method of claim 1 and for measuring the content of metal impurities in a liquid, An ion exchanger through which the above liquid passes; and An integrating flow meter for measuring the volume of liquid passed through the above ion exchanger Includes, The above ion exchanger is used by connecting two or more units of the same ion type in series, and A measuring device having a volume of 0.5 to 5.0 ml per unit of the above-mentioned ion exchanger, and a differential pressure coefficient of 0.01 MPa/LV/m or less per unit.
In Paragraph 10, A measuring device in which the above ion exchanger is a monolithic organic porous ion exchanger.
In Article 10 or Article 11, A measuring device in which the number of units of the above-mentioned ion exchanger is the minimum number such that the content of metal impurities analyzed based on the last ion exchanger is less than the quantitative lower limit.

Description

Analysis method for metal impurity content The present invention relates to an analysis method for analyzing the content of metal impurities contained in trace amounts in liquids such as ultrapure water, process water during an ultrapure water manufacturing process, chemicals used for semiconductor cleaning, or organic solvents, and a measuring device used in the method. In semiconductor and pharmaceutical manufacturing processes, ultrapure water with extremely low levels of ionic impurities is utilized. Therefore, in the production of ultrapure water used in these processes, it is important to determine the amount of trace ionic impurities contained in the final ultrapure water or the process water used in the ultrapure water production process. Patent Document 1 discloses an analysis method in which a predetermined amount of fluid is passed through a porous membrane having a functional group having an ion exchange function, impurities in the fluid are captured by the porous membrane, the captured impurities are eluted from the porous membrane, the concentration of impurities in the eluent is measured, and the concentration of impurities in the fluid is calculated from the measured concentration. However, although the types and forms of metal impurities in ultrapure water are not certain, there is a possibility that they exist in aggregated colloids or dispersed fine particles in addition to ionic forms. The surface charge density of colloids and fine particles is lower than that of ions, and thus the electrostatic interaction with the ion exchange resin is small. Patent document 2 discloses a method for analyzing trace amounts of metal impurities in ultrapure water by using a monolithic organic porous ion exchanger instead of a porous membrane. Monolithic organic porous ion exchangers have a network of flow paths and, in addition to electrostatic interactions, possess the ability to physically adsorb or capture fine particles. Furthermore, by using monolithic organic porous anion exchangers, metal impurities in a complexed anionic state can be adsorbed or captured. Additionally, by using monolithic organic porous cation exchangers, metal ions in a cationic state can be adsorbed or captured. In other words, metal impurities in ultrapure water can be effectively adsorbed or captured. FIG. 1 is a conceptual diagram illustrating an example of a combination (measuring device) of an ion exchanger according to the present invention. FIG. 2 is a conceptual diagram illustrating another example of a combination (measuring device) of an ion exchanger according to the present invention. FIG. 3 is a conceptual diagram illustrating another example of a combination (measuring device) of an ion exchanger according to the present invention. The analysis method of the present invention is a method for analyzing the content of metal impurities in a liquid, and the method is, A pass-through step of passing liquid through an ion exchanger; An elution step of recovering metal impurities captured in the ion exchanger by eluting them with an eluent; and A measurement step that analyzes the eluent containing eluted metal impurities to measure the content of metal impurities in the said eluent. Includes, The above ion exchanger is used by connecting two or more units of the same ion type in series, and the volume per unit of the above ion exchanger is 0.5 to 5.0 ml. In particular, in the present invention, the elution step and the measurement step are performed sequentially from the top for each unit of the ion exchanger, and the content of metal impurities in the liquid measured in the measurement step is less than a quantitative lower limit. In this case, the total amount of metal impurities in the liquid until it becomes less than the quantitative lower limit is defined as the content of metal impurities in the liquid. In the present invention, the ion exchanger used is not particularly limited, and any inorganic or organic material may be used as long as it has a functional group having ion exchange capability introduced, such as in membrane form, granular form (resin), or porous material. In particular, it is preferable to use a porous ion exchanger described below, and it is especially preferable to use a monolithic organic porous ion exchanger. Below, the case where a monolithic organic porous ion exchanger (simply referred to as a monolithic ion exchanger) is used will be described. Examples of liquids subject to analysis include ultrapure water, process water during the ultrapure water manufacturing process, chemicals and organic solvents used for semiconductor cleaning, and other liquids where the presence of trace amounts of metal impurities is a problem. Below, ultrapure water will be described as an example of a liquid. (Passage stage) The ultrapure water to be analyzed is passed through a porous ion exchanger (monolithic ion exchanger), and metal impurities in the ultrapure water are captured by the monolithic ion ex