JP7645269B2 - Method for purifying polar organic solvent, apparatus for purifying polar organic solvent, analysis method, and method for producing purified polar organic solvent - Google Patents

Description

The present invention relates to a method for purifying a polar organic solvent to obtain a high-purity polar organic solvent with a reduced content of ionic impurities, and a polar organic solvent purification device for carrying out the method. The present invention also relates to an analytical method using the purified polar organic solvent, and a method for producing the purified polar organic solvent.

ICP-MS is used to analyze trace metals in organic solvents. When using ICP-MS to analyze metals in the organic solvent to be measured, a standard solution containing a known concentration is diluted in several stages with a blank solution of the same type of organic solvent as the material to be measured, and a calibration curve is created.

When creating this calibration curve, the metal concentration in the organic solvent to be measured is set to fall within the calibration curve concentration range. This type of method is called the absolute calibration curve method, and it is important that the blank solution does not contain the metal to be measured. If the metal concentration in the blank solution is high, the background concentration will be high, and the lower limit of quantification will rise.

For this reason, the metal impurity content in blank solutions used for trace metal analysis in organic solvents by ICP-MS is required to be 1 ppt or less.

In addition, in the semiconductor manufacturing process, metal impurities contained in isopropyl alcohol (IPA) used for cleaning are likely to have adverse effects on wafers, so it is necessary to reduce the impurity content in IPA to the ppt level or below 1 ppt.

As a method for purifying an organic solvent, for example, Patent Document 1 discloses a method for removing ionic contaminants from a hydrolyzable organic solvent, which comprises contacting the hydrolyzable organic solvent with a mixed bed of ion exchange resins including a cation exchange resin and an anion exchange resin, and the anion exchange resin is selected from weakly basic anion exchange resins.

Furthermore, Patent Document 2 discloses a method for removing ionic contaminants from a hydrophilic organic solvent, the method comprising contacting the hydrophilic organic solvent with a mixed bed of ion exchange resins containing a cationic ion exchange resin and an anionic ion exchange resin, in which (a) the cationic ion exchange resin is a hydrogen (H)-type strong acid cationic ion exchange resin having a water retention capacity of 40 to 55% by weight, and (b) both the cationic ion exchange resin and the anionic ion exchange resin have a porosity of 0.001 to 0.1 cm ³ /g, an average pore size of 0.001 to 1.7 nm, and a BET surface area of 0.001 to 10 m ² /g.

In Patent Documents 1 and 2, the organic solvent is purified by contacting the organic solvent with a mixed bed of ion exchange resins containing a cation exchange resin and an anion exchange resin.

Special table 2019-509165 publication Special table 2019-509882 publication

However, although the methods described in Patent Documents 1 and 2 can remove metal impurities from organic solvents, there are cases where even higher purification is required. In particular, polar organic solvents are used as cleaning agents and drying agents for wafers in the semiconductor manufacturing process, and therefore even higher purification is required. Therefore, there is a demand for a purification method for polar organic solvents that has excellent metal impurity removal properties.

In addition, the diffusion rate of ionic impurities is slow in organic solvents, and the reaction rate of the ion exchange reaction with ion exchange resins is also slow, so when ionic metal impurities are removed from organic solvents using ion exchange resins, the removal efficiency is lower than when ionic impurities are removed from water.

Alternatively, because the diffusion rate of ionic impurities is low in organic solvents and the reaction rate of the ion exchange reaction with ion exchange resins is also low, when removing ionic metal impurities in organic solvents, the flow rate through the ion exchange resin must be set lower than when removing ionic metal impurities in water. For example, when using a strongly acidic cation exchange resin, it is difficult to obtain the same metal removal rate at the same flow rate as in water. Therefore, in order to purify ionic metal impurities in organic solvents using ion exchange resins, the flow rate through the ion exchange resin must be set lower, resulting in a problem of low purification efficiency.

Therefore, the first object of the present invention is to provide a method for purifying a polar organic solvent and a method for producing a purified polar organic solvent that are excellent in removing ionic impurities in a polar organic solvent. The second object of the present invention is to provide a method for purifying a polar organic solvent and a method for producing a purified polar organic solvent that are excellent in removing ionic impurities in a polar organic solvent and have high purification efficiency.

Against this technical background, the inventors conducted extensive research and discovered that adding water to a polar organic solvent and then contacting it with an ion exchange resin improves the ability to remove ionic metal impurities compared to when water is not added, which led to the completion of the present invention.

That is, the present invention (1) includes a water addition step of adding water to a polar organic solvent;
a purification step of contacting the polar organic solvent to which water has been added with an ion exchanger to obtain a purified polar organic solvent in which ionic metal impurities have been reduced ;
having
the polar organic solvent is an alcohol or an ether compound, or a mixed solvent containing at least one of an alcohol and an ether compound;
The polar organic solvent contains at least one of Na, K, Li, Cr, As, Ca, Cu, Fe, Mg, Mn, Ni, Pb, and Zn as an ionic metal impurity,
the water content of the polar organic solvent before the addition of water is 200 ppm by mass or less, and the amount of water added to the polar organic solvent in the water addition step is 150 mass% or more as a ratio to the water content in the polar organic solvent before the addition of water ((amount of water added to the polar organic solvent/water content in the polar organic solvent before the addition of water)×100);
The present invention provides a method for purifying a polar organic solvent, comprising the steps of:

The present invention ( 2 ) also provides the method for purifying a polar organic solvent according to (1), characterized in that in the water addition step, water is added to the polar organic solvent in such a range that the water content in the polar organic solvent to which the water has been added is 0.01 to 20.0 mass %.

The present invention ( 3 ) also provides a method for purifying a polar organic solvent according to (1) or (2) , characterized in that the ion exchanger is one or more of a cation exchanger, an anion exchanger and an H-type chelate exchanger.

The present invention ( 4 ) also provides a method for purifying a polar organic solvent according to any one of (1) to ( 3 ), characterized in that the polar organic solvent is a solvent capable of dissolving 1.0 g or more of water per 100.0 g at 25° C.

The present invention ( 5 ) also provides a method for purifying a polar organic solvent according to any one of (1) to ( 4 ), characterized in that the purified polar organic solvent is a solvent used as a diluent in metal concentration analysis using ICP-MS.

The present invention ( 6 ) also provides a filter comprising an ion exchanger packed part packed with an ion exchanger,
a water adding section for adding water to the polar organic solvent;
a polar organic solvent supplying section for supplying the polar organic solvent to which water has been added by the water adding section to the section packed with the ion exchanger;
The present invention provides an apparatus for purifying a polar organic solvent for carrying out any one of the methods for purifying a polar organic solvent according to (1) to (5), comprising:

The present invention ( 7 ) also provides an apparatus for purifying a polar organic solvent as described in ( 6 ), characterized in that the liquid-contacting part is formed of or coated with a fluorine-based resin.

The present invention ( 8 ) also provides a method for producing a polar organic solvent, comprising:
a purification step of contacting the polar organic solvent to which water has been added with an ion exchanger to obtain a purified polar organic solvent;
and creating a calibration curve by using the purified polar organic solvent as a dilution solvent ,
the polar organic solvent is an alcohol or an ether compound, or a mixed solvent containing at least one of an alcohol and an ether compound;
The present invention provides a method for analyzing a metal concentration using ICP-MS, wherein the polar organic solvent contains, as an ionic metal impurity, at least one of Na, K, Li, Cr, As, Ca, Cu, Fe, Mg, Mn, Ni, Pb, and Zn .

The present invention ( 9 ) also provides a method for producing a polar organic solvent, comprising:
a purification step of contacting the polar organic solvent to which water has been added with an ion exchanger to obtain a purified polar organic solvent in which ionic metal impurities have been reduced ;
having
the polar organic solvent is an alcohol or an ether compound, or a mixed solvent containing at least one of an alcohol and an ether compound;
The polar organic solvent contains at least one of Na, K, Li, Cr, As, Ca, Cu, Fe, Mg, Mn, Ni, Pb, and Zn as an ionic metal impurity,
the water content of the polar organic solvent before the addition of water is 200 ppm by mass or less, and the amount of water added to the polar organic solvent in the water addition step is 150 mass% or more as a ratio to the water content in the polar organic solvent before the addition of water ((amount of water added to the polar organic solvent/water content in the polar organic solvent before the addition of water)×100);
The present invention provides a method for producing a purified polar organic solvent, comprising the steps of:

The present invention ( 10 ) also provides the method for producing a purified polar organic solvent according to ( 9 ), wherein the purified polar organic solvent is a diluent for metal concentration analysis using ICP-MS.

According to the present invention, it is possible to provide a method for purifying a polar organic solvent and a method for producing a purified polar organic solvent, which are excellent in removing ionic impurities in the polar organic solvent. Furthermore, according to the present invention, it is possible to provide a method for purifying a polar organic solvent and a method for producing a purified polar organic solvent, which are excellent in removing metal impurities in the polar organic solvent and have high purification efficiency. Furthermore, according to the present invention, it is possible to provide an analysis method with high measurement accuracy.

FIG. 1 is a diagram showing an example of an apparatus for purifying a polar organic solvent according to the present invention. 1 is a graph showing the amount of Na adsorption for each water content in Example 7.

The method for purifying a polar organic solvent of the present invention includes a water addition step of adding water to a polar organic solvent;
a purification step of contacting the polar organic solvent to which water has been added with an ion exchanger to obtain a purified polar organic solvent;
The method for purifying a polar organic solvent is characterized by having the following:

The water addition process in the polar organic solvent purification method of the present invention is a process of adding water to a polar organic solvent.

In the water addition process, the polar organic solvent to which water is added is the treated liquid to be purified in the polar organic solvent purification method of the present invention.

The polar organic solvent in the method for purifying a polar organic solvent of the present invention is not particularly limited as long as it has polarity and can dissolve water, and examples thereof include alcohols such as isopropyl alcohol, methanol, ethanol, and propanol, ester compounds such as propylene glycol monomethyl ether acetate (PGMEA), ether compounds such as propylene glycol monomethyl ether (PGME), polyether compounds, and mixed solvents of one or more of these. In addition, examples of mixed solvents of one or more of these include mixed solvents of two or more of the same category of solvents, such as mixed solvents of two or more alcohols, mixed solvents of two or more ester compounds, and mixed solvents of two or more ether compounds; and mixed solvents in which at least two types of solvents of different categories are mixed, such as mixed solvents of one or more alcohols and one or more ester compounds. The polar organic solvent may be a protic polar organic solvent or an aprotic organic solvent.

The polar organic solvent contains metal impurities, including monovalent ionic metal impurities such as Na, K, and Li, and divalent or higher ionic metal impurities such as Cr, As, Ca, Cu, Fe, Mg, Mn, Ni, Pb, and Zn.

The content of each metal impurity in the polar organic solvent is not particularly limited, but is typically approximately 100 ppb to 20 ppt by mass.

The method for purifying a polar organic solvent of the present invention is effective as long as the solvent is capable of dissolving even a small amount of water, but it is preferable that the polar organic solvent be a solvent capable of dissolving 1.0 g or more of water per 100.0 g at 25°C.

In the water addition step of the method for purifying a polar organic solvent of the present invention, the water to be added to the polar organic solvent is not particularly limited, but the lower the content of ionic impurities, the less the load on the ion exchanger is, so it is preferable. In the water addition step, the water to be added to the polar organic solvent includes pure water having a metal impurity content of 3 ng/L or less, and ultrapure water having a metal impurity content of 1 ng/L or less, and of these, ultrapure water is preferred.

In the method for purifying a polar organic solvent of the present invention, the water content of the polar organic solvent before adding water in the water addition step is not particularly limited. The method for purifying a polar organic solvent of the present invention is preferably used for purifying a solvent that requires high purity, so in the purification of such a solvent that requires high purity, the polar organic solvent to be treated often has a low water content, and in this case, the water content of the polar organic solvent before adding water is preferably 200 mass ppm or less. In addition, the method for purifying a polar organic solvent of the present invention is also effective for the purification of a polar organic solvent with a high water content, so in the purification of such a solvent, the water content of the polar organic solvent to be treated before adding water is, for example, 200 mass ppm to 1.0 mass%.

In the method for purifying a polar organic solvent of the present invention, in the water addition step, by adding water to the polar organic solvent to be treated, metal impurities are easily ionized in the polar organic solvent, and functional groups are easily dissociated, so the amount of ions removed by the ion exchange reaction increases, and the amount of metal impurities adsorbed to the ion exchanger increases. Therefore, if water is added to the polar organic solvent in the water addition step, the effect is achieved, so the amount of water added to the polar organic solvent is not particularly limited, but with regard to the amount of water added to the polar organic solvent in the water addition step, it is preferable to add water to the polar organic solvent in such a range that the water content in the polar organic solvent to which water has been added is 0.01 to 20.0% by mass, it is more preferable to add water to the polar organic solvent in such a range that the water content in the polar organic solvent to which water has been added is 0.01 to 10.0% by mass, and it is particularly preferable to add water to the polar organic solvent in such a range that the water content in the polar organic solvent to which water has been added is 0.10 to 5.0% by mass. That is, in the water addition step, the water content in the polar organic solvent after the water is added is preferably 0.01 to 20.0 mass%, more preferably 0.01 to 10.0 mass%, and particularly preferably 0.10 to 5.0 mass%.

In addition, the amount of water added to the polar organic solvent in the water addition step is preferably 150% by mass or more, more preferably 200% by mass or more, and particularly preferably 200 to 500% by mass, as a ratio to the water content in the polar organic solvent before the addition of water ((amount of water added to polar organic solvent/water content in polar organic solvent before the addition of water) x 100). For example, if the water content in the polar organic solvent before the addition of water is 0.05% by mass, and an amount of water equivalent to 0.05% by mass relative to the polar organic solvent before the addition of water is added in the water addition step, the ratio of the amount of water added to the polar organic solvent in the water addition step to the water content in the polar organic solvent before the addition of water is 100% by mass.

In the water addition step, the method of adding water to the polar organic solvent is not particularly limited, and examples include a method of adding a predetermined amount of water to a storage container in which the polar organic solvent to be supplied to the ion exchanger is stored, and stirring the solvent in the storage container as necessary, and a method of connecting a water supply pipe to a polar organic solvent supply pipe for supplying the polar organic solvent to the ion exchanger, and supplying water from the water supply pipe, thereby adding water to the polar organic solvent in the polar organic solvent supply pipe.

The purification process involves contacting the polar organic solvent to which water has been added in the water addition process with an ion exchanger to obtain a purified polar organic solvent.

Examples of ion exchangers include cation exchangers, anion exchangers, H-type chelate exchangers, and boron-selective ion exchangers. The ion exchangers may be one type alone or two or more types in combination. The ion exchangers may be used in a single bed of a cation exchanger, anion exchanger, H-type chelate exchanger, or boron-selective ion exchanger, or may be used in a mixed bed or multiple beds of two or more of the above ion exchangers.

It is preferable that the cation exchanger is in the H type, since the content of ionic impurities can be reduced. In addition, the cation exchanger may be in the tetraalkylammonium ion type, such as the TMA type (tetramethylammonium ion type) or the TBA type (tetrabutylammonium ion type), so long as it does not contain a metal element. In addition, the cation exchanger may be a strongly acidic cation exchanger having a strongly acidic cation exchange group, or a weakly acidic cation exchanger having a weakly acidic cation exchange group.

The cation exchanger may be a granular cation exchange resin. The substrate of the cation exchange resin is a styrene-divinylbenzene copolymer. The cation exchange resin may have any of a gel structure, a macroporous structure, and a porous structure. The ion exchange capacity of the cation exchange resin in a wet state is preferably 0.5 (eq/L-R) or more, and particularly preferably 1.0 (eq/L-R) or more. The ion exchange capacity of the cation exchange resin in a wet state is preferably as high as possible, and is selected appropriately. The harmonic mean diameter of the cation exchange resin is preferably 200 to 900 μm, and particularly preferably 300 to 600 μm.

Examples of strong acid cation exchange resins include Amberlite IR120B, IR124, 200CT252, Amberjet 1020, 1024, 1060, and 1220 manufactured by The Dow Chemical Company, and Diaion SK104, SK1B, SK110, SK112, PK208, PK212L, PK216, and PK21 manufactured by Mitsubishi Chemical Corporation. Examples of the weakly acidic cation exchange resin include FPC3500 and IRC76 manufactured by Organo, Diaion WK10, WK11, WK100 and WK40L manufactured by Mitsubishi Chemical Corporation, C104, C106, C107E, C115E and SSTC104 manufactured by Purolite, and CNP80WS manufactured by Lewatit.

An example of the cation exchanger is an organic porous cation exchanger. The organic porous cation exchanger is an organic porous material into which a cation exchange group has been introduced. The exchange capacity in the organic porous strongly acidic cation exchanger is preferably 1 to 3 mg equivalents/mL (dry state), and particularly preferably 1.5 to 3 mg equivalents/mL (dry state).

The cation exchanger may be a single type or a combination of two or more types.

It is preferable that the anion exchanger is in the OH form, since the content of ionic impurities can be reduced. The anion exchanger may be in any ionic form that does not contain metal elements, and may be in the carbonate form, bicarbonate form, or organic acid form. The anion exchanger may be a strongly basic anion exchanger having a strongly basic anion exchange group as the anion exchange group, or a weakly basic anion exchanger having a weakly basic anion exchange group as the anion exchange group.

Strongly basic anion exchange groups related to strongly basic anion exchangers include OH-type quaternary ammonium groups. Weakly basic anion exchange groups related to weakly basic anion exchangers include tertiary amino groups, secondary amino groups, primary amino groups, polyamine groups, etc. In addition, for highly basic OH-type anion exchangers, carbonate or bicarbonate anion exchangers with low basicity may be used in solvents where decomposition or chemical reactions occur.

An example of an anion exchanger is a granular anion exchange resin. The substrate of the anion exchange resin is a styrene-divinylbenzene copolymer. The anion exchange resin may have any of a gel structure, a macroporous structure, and a porous structure. The ion exchange capacity of the anion exchange resin in a wet state is preferably 0.5 to 2 (eq/L-R), and more preferably 0.9 to 2 (eq/L-R). The harmonic mean diameter of the anion exchange resin is preferably 200 to 900 μm, and more preferably 300 to 800 μm.

Examples of anion exchange resins include Amberlite IRA 900, 402, 96SB, 98, Amberjet 4400, 4002, and 4010 manufactured by The Dow Chemical Company; Diaion UBA120, PA306S, PA308, PA312, PA316, PA318L, WA21J, and WA30 manufactured by Mitsubishi Chemical Corporation; DS-2, DS-5, and DS-6 manufactured by Organo Corporation; A400, A600, SGA550, A500, A501P, A502PS, A503, A100, A103S, A110, A111S, and A133S manufactured by Purolite Corporation; and Monoplus M500, M800, MP62WS, and MP64 manufactured by Lewatit.

An example of an anion exchanger is an organic porous anion exchanger. The organic porous anion exchanger is an organic porous material into which an anion exchange group, such as the strongly basic anion exchange group or the weakly basic anion exchange group listed above, has been introduced. The exchange capacity of the organic porous anion exchanger is preferably 1 to 6 mg equivalents/mL (dry state), and particularly preferably 2 to 5 mg equivalents/mL (dry state).

The anion exchanger may be a single type or a combination of two or more types.

It is preferable that the chelate exchanger is in the H type, since this reduces the content of ionic impurities. In addition, the chelate exchanger may be in the ammonium type, such as the TMA type (tetramethylammonium ion type) or the TBA type (tetrabutylammonium ion type), as long as it does not contain metal elements.

H-form chelate exchangers are chelate exchangers in metal ion form, such as Na-form, Ca-form, or Mg-form, that have been converted to H-form by contacting them with a mineral acid and treating them with an acid. In other words, H-form chelate exchangers are the product of contacting a metal ion-form chelate exchanger with a mineral acid.

The functional group possessed by the H-type chelate exchanger is not particularly limited as long as it can coordinate with a metal ion to form a chelate, and examples thereof include functional groups having an amino group such as an iminodiacetic acid group, an aminomethyl phosphate group, or an iminopropionic acid group, and a thiol group. Of these, functional groups having an amino group are preferred as the functional group of the chelate exchanger, in that they enhance the removal of many polyvalent metal ions, and iminodiacetic acid groups, aminomethyl phosphate groups, and iminopropionic acid groups are particularly preferred.

An example of the H-type chelate exchanger is a granular H-type chelate exchange resin. An example of the substrate of the H-type chelate exchange resin is a styrene-divinylbenzene copolymer. The H-type chelate exchange resin may have any of a gel structure, a macroporous structure, and a porous structure. The exchange capacity of the H-type chelate exchange resin is preferably 0.5 to 2.5 eq/L-R, and more preferably 1.0 to 2.5 eq/L-R. The average particle size (harmonic mean diameter) of the H-type chelate exchange resin is not particularly limited, but is preferably 300 to 1000 μm, and more preferably 500 to 800 μm. The average particle size of the H-type chelate exchange resin is a value measured by a laser diffraction particle size distribution measuring device.

Examples of H-type chelate exchangers include H-type organic porous chelate exchangers. H-type organic porous chelate exchangers are organic porous bodies into which functional groups having chelating ability, such as the functional groups having chelating ability listed above, have been introduced. The exchange capacity in the H-type organic porous chelate exchanger is preferably 0.3 to 2 mg equivalents/mL (in a water-wet state), and particularly preferably 1 to 2 mg equivalents/mL (in a water-wet state).

The H-type chelate exchanger can be obtained by contacting a metal ion type chelate exchanger, such as a Na-type, Ca-type, or Mg-type, with a mineral acid for acid treatment. Examples of mineral acids that can be contacted with the metal ion type chelate exchanger include hydrochloric acid, sulfuric acid, and nitric acid. Of these, hydrochloric acid and sulfuric acid are preferred from the standpoint of safety. Furthermore, in the case of conversion from the Ca-type, hydrochloric acid is preferred because of the risk of calcium sulfate precipitation. The concentration of the mineral acid is preferably 0.1 to 6N, and particularly preferably 1 to 4N.

The method of contacting the mineral acid with the metal ion type chelate exchanger is not particularly limited, and the contact mode, contact temperature, contact time, etc. are selected as appropriate.

After contacting the metal ion chelate exchanger with mineral acid, the H-type chelate exchanger that has been converted to H-type is washed with water to remove excess mineral acid. However, since the functional groups in the chelate exchanger are bonded to the mineral acid by hydrogen bonds, etc., the excess mineral acid cannot be completely removed by washing with water. Therefore, the mineral acid used in the acid treatment remains in the H-type chelate exchanger.

For example, metal ion type chelate exchange resins include CR-10 and CR-11 manufactured by Mitsubishi Chemical Corporation, Duolite C-467 manufactured by Sumika Chemtex Corporation, MC-700 manufactured by Sumitomo Chemical Co., Ltd., Lewatit TP207, Lewatit TP208, and Lewatit TP260 manufactured by Lanxess AG, S930 and S950 manufactured by Purolite Corporation, and DS-21 and DS-22 manufactured by Organo.

The chelate exchanger may be a single type or a combination of two or more types.

Examples of organic porous ion exchangers, such as organic porous cation exchangers, organic porous anion exchangers, and organic porous chelate exchangers, include organic porous ion exchangers (hereinafter also referred to as a first form of organic porous ion exchanger) that are composed of a continuous skeleton phase and a continuous pore phase, in which the thickness of the continuous skeleton is 1 to 100 μm, the average diameter of the continuous pores is 1 to 1000 μm, the total pore volume is 0.5 to 50 mL/g, ion exchange groups (chelate exchange groups, cation exchange groups, or anion exchange groups) are introduced, the ion exchange capacity per weight in a dry state is 1 to 6 mg equivalents/g, and the ion exchange groups are uniformly distributed throughout the organic porous ion exchanger.

An example of a first type of organic porous ion exchanger is an organic porous ion exchanger having an open cell structure in which bubble-like macropores overlap each other and the overlapping portions form openings with an average diameter of 1 to 1000 μm, a total pore volume of 1 to 50 mL/g, ion exchange groups introduced therein, an ion exchange capacity per weight in a dry state of 1 to 6 mg equivalents/g, and the ion exchange groups uniformly distributed throughout the organic porous ion exchanger.

In addition, examples of the first type of organic porous ion exchanger include an organic porous ion exchanger that has a continuous macropore structure in which bubble-like macropores overlap each other and the overlapping portions form openings with an average diameter of 30 to 300 μm, has a total pore volume of 0.5 to 10 ml/g, has cation exchange groups or anion exchange groups introduced, has an ion exchange capacity per weight in a dry state of 1 to 6 mg equivalents/g, has ion exchange groups uniformly distributed throughout the organic porous ion exchanger, and in an SEM image of a cut surface of the continuous macropore structure (dried body), the area of the skeleton appearing on the cross section is 25 to 50% of the image area.

In addition, examples of the organic porous ion exchanger of the first embodiment include an organic porous ion exchanger in which the organic porous ion exchanger is a bicontinuous structure consisting of a three-dimensionally continuous skeleton having an average thickness of 1 to 60 μm and made of an aromatic vinyl polymer containing 0.1 to 5.0 mol % of crosslinked structural units among all structural units into which ion exchange groups (chelate exchange groups, cation exchange groups, or anion exchange groups) have been introduced, and three-dimensionally continuous pores having an average diameter of 10 to 200 μm between the skeletons, the total pore volume being 0.5 to 10 mL/g, cation exchange groups being introduced, an ion exchange capacity per weight in a dry state being 1 to 6 mg equivalents/g, and the ion exchange groups being uniformly distributed in the organic porous ion exchanger.

In the purification process, the method for contacting the polar organic solvent to which water has been added with the ion exchanger is not particularly limited, and examples include a method in which the ion exchanger is packed into a packed container or packed column, and the polar organic solvent to which water has been added is supplied to the packed container or packed column of the ion exchanger.

In the purification step, the conditions for contacting the polar organic solvent to which water has been added with the ion exchanger are not particularly limited. For example, the flow rate (SV) is preferably 1 to 30 h ⁻¹ , and particularly preferably 2 to 10 h ⁻¹ .

In the purification process, the polar organic solvent to which water has been added is brought into contact with an ion exchanger, so that ionic impurities in the polar organic solvent are adsorbed onto the ion exchanger and removed. By carrying out the purification process in this manner, a purified polar organic solvent with reduced ionic impurities can be obtained.

In the purification step, a particulate removal filter may be combined with the ion exchanger to remove impurities from the polar organic solvent. In the purification method of the polar organic solvent of the present invention, the polar organic solvent to be treated may be treated using a particulate removal filter before the water addition step, or the polar organic solvent to be treated may be treated using a particulate removal filter after the water addition step. The particulate removal filter may be placed either before or after the ion exchanger, or both before and after the ion exchanger. Since it is known that particulates may be charged in water, the particulate removal filter may be used to treat the polar organic solvent before the water addition step, or may be placed before the ion exchanger after the water addition step, thereby reducing the amount of impurities loaded on the ion exchanger.

The purified polar organic solvent obtained by carrying out the polar organic solvent purification method of the present invention contains water that was present before the treatment and water added in the water addition step, but since ionic impurities are greatly reduced, purification to an impurity level of 1 mass ppt or less is possible. Therefore, the purified polar organic solvent obtained by carrying out the polar organic solvent purification method of the present invention is suitable as a solvent for dilution (blank solution for calibration curve) in metal concentration analysis using ICP-MS for trace metal analysis, a solvent for diluting samples, and a solvent for cleaning instruments and analytical equipment. In other words, the polar organic solvent purification method of the present invention is suitable as a method for producing a solvent used in metal concentration analysis using ICP-MS.

The purified polar organic solvent obtained by carrying out the purification method of the polar organic solvent of the present invention can be used in ICP-MS analysis as a dilution solution for low-polarity or non-polar organic solvents that are difficult to mix with water. In particular, since the mixed standard solution of ICP-MS is generally an aqueous solution, even if the mixed standard solution (aqueous solution) of ICP-MS is added to a low-polarity or non-polar organic solvent, it may not be mixed sufficiently, and the analytical accuracy may decrease. Therefore, the mixed standard solution (aqueous solution) of ICP-MS can be added to the purified polar organic solvent obtained by carrying out the purification method of the polar organic solvent of the present invention, and the purified polar organic solvent containing the mixed standard solution can be added to the low-polarity or non-polar organic solvent to be analyzed, to create a calibration curve. In addition, the measurement accuracy can be improved by diluting the low-polarity or non-polar organic solvent with the purified polar organic solvent obtained by carrying out the purification method of the polar organic solvent of the present invention. Therefore, it is possible to analyze any organic solvent, polar, low-polarity, or non-polar, by using the purified polar organic solvent obtained by carrying out the purification method of the polar organic solvent of the present invention.

The method for purifying a polar organic solvent of the present invention can also be used as a method for producing and recovering a solvent for applications such as cleaning electronic components and machines using a polar organic solvent that is tolerant of containing a small amount of water. The method for purifying a polar organic solvent of the present invention can also be used as a method for producing a solvent for applications such as cleaning and diluting solutions for electronic components and materials for semiconductor manufacturing processes that require very low levels of ionic impurities and low water content by combining it with a subsequent water removal method in applications that require a very low amount of ionic impurities in the solvent.

The method for producing a purified polar organic solvent of the present invention includes a water addition step of adding water to a polar organic solvent;
a purification step of contacting the polar organic solvent to which water has been added with an ion exchanger to obtain a purified polar organic solvent;
The present invention relates to a method for producing a purified polar organic solvent, the method comprising the steps of:

The water addition step and purification step in the method for producing a purified polar organic solvent of the present invention are the same as the water addition step and purification step in the method for purifying a polar organic solvent of the present invention.

The use of the purified polar organic solvent obtained by carrying out the method for producing a purified polar organic solvent of the present invention includes a dilution solution for metal concentration analysis using ICP-MS. In other words, the purified polar organic solvent obtained by carrying out the method for producing a purified polar organic solvent of the present invention can be used in ICP-MS analysis as a dilution solution for a low-polarity or non-polar organic solvent that is difficult to mix with water. In particular, since the mixed standard solution for ICP-MS is generally an aqueous solution, even if the mixed standard solution (aqueous solution) for ICP-MS is added to a low-polarity or non-polar organic solvent, it may not be mixed sufficiently, and the analytical accuracy may decrease. Therefore, a calibration curve can be created by adding a mixed standard solution (aqueous solution) for ICP-MS to the purified polar organic solvent obtained by carrying out the method for producing a purified polar organic solvent of the present invention, and adding the purified polar organic solvent containing the mixed standard solution to the low-polarity or non-polar organic solvent to be analyzed. In addition, the measurement accuracy can be improved by diluting a low-polarity or non-polar organic solvent using the purified polar organic solvent obtained by carrying out the method for producing a purified polar organic solvent of the present invention. Therefore, it is possible to analyze any organic solvent, polar, low-polarity, or non-polar, using the purified polar organic solvent obtained by carrying out the method for producing a purified polar organic solvent of the present invention.

In other words, an example of the method for producing a purified polar organic solvent of the present invention is a method for producing a purified polar organic solvent used as a diluent for metal concentration analysis using ICP-MS. In other words, the method for producing a diluent of the present invention is a method for producing a diluent for metal concentration analysis using ICP-MS, which includes a water addition step of adding water to a polar organic solvent, and a purification step of contacting the polar organic solvent to which water has been added with an ion exchanger to obtain a purified polar organic solvent used as a diluent for metal concentration analysis using ICP-MS. The water addition step and purification step in the method for producing a diluent of the present invention are the same as the water addition step and purification step in the method for purifying a polar organic solvent of the present invention.

The apparatus for purifying a polar organic solvent of the present invention comprises: an ion exchanger packed section packed with an ion exchanger;
a water adding section for adding water to the polar organic solvent;
a polar organic solvent supplying section for supplying the polar organic solvent to which water has been added by the water adding section to the section packed with the ion exchanger;
The purification apparatus for a polar organic solvent is characterized by comprising:

The polar organic solvent purification apparatus of the present invention will be described with reference to FIG. 1. FIG. 1 is a diagram showing an example of the form of the polar organic solvent purification apparatus of the present invention. In FIG. 1, the polar organic solvent purification apparatus 1 has an ion exchanger-packed column 7 packed with an ion exchanger, a polar organic solvent supply pipe 4 for supplying the polar organic solvent 2 to be treated to the ion exchanger-packed column 7, and a purified polar organic solvent discharge pipe 8 for discharging the treatment liquid treated with the ion exchanger in the ion exchanger-packed column 7, i.e., the purified polar organic solvent 9. The polar organic solvent supply pipe 4 is connected to a water addition pipe 10 for supplying ultrapure water 3. The polar organic solvent supply pipe 4 is provided with a pump 5 for adjusting the supply amount of the polar organic solvent 2, and the water addition pipe 10 is provided with a pump 6 for adjusting the supply amount of the ultrapure water 3.

In the polar organic solvent purification device 1, the polar organic solvent 2 is supplied from the polar organic solvent supply pipe 4 toward the ion exchanger packed column 7 while adjusting the supply amount with the pump 5, and ultrapure water 3 is supplied from the water addition pipe 10 into the polar organic solvent supply pipe 4 while adjusting the supply amount with the pump 6. At this time, the ultrapure water 3 is added to the polar organic solvent 2 at the position 11 where the water addition pipe 10 is connected, and the polar organic solvent 2 is mixed with the ultrapure water 3 in the polar organic solvent supply pipe 4 downstream of the position 11, and water is dissolved in the polar organic solvent. Next, the polar organic solvent 12 to which water has been added is supplied into the ion exchanger packed column 7, and the polar organic solvent 12 to which water has been added comes into contact with the ion exchanger. Then, the treated liquid that has been treated by contacting with the ion exchanger, i.e., the purified polar organic solvent 9, is discharged from the purified polar organic solvent discharge pipe 8.

The polar organic solvent purification apparatus of the present invention is suitable for carrying out the above-mentioned polar organic solvent purification method of the present invention.

The ion exchanger-filled section of the polar organic solvent purification apparatus of the present invention is a section filled with an ion exchanger, and is a section for contacting the polar organic solvent to which water has been added with the ion exchanger. The ion exchanger filled in the ion exchanger-filled section is the same as the ion exchanger in the polar organic solvent purification method of the present invention. The form of the ion exchanger-filled section is not particularly limited, and examples thereof include a packed vessel filled with an ion exchanger, a packed column filled with an ion exchanger, a cartridge-shaped packed vessel, a resin tower, and the like.

The water addition section of the polar organic solvent purification apparatus of the present invention is a section for adding water to the polar organic solvent. The form of the water addition section is not particularly limited, and examples thereof include a water addition section consisting of a water addition tube connected to a polar organic solvent supply tube for supplying the polar organic solvent to an ion exchanger, a pump for adjusting the amount of water supplied to the polar organic solvent supply tube, a mass flow controller linked to the pump, an electric flow control valve, and the like, as shown in the form example in FIG. 1. Other examples of the water addition section include a syringe pump for low flow rate addition.

The polar organic solvent supply unit of the polar organic solvent purification apparatus of the present invention is a portion for supplying the polar organic solvent to which water has been added by the water addition unit to the packed section of the ion exchanger. As an example of the polar organic solvent supply unit shown in FIG. 1, a polar organic solvent supply unit consisting of a polar organic solvent supply pipe for supplying the polar organic solvent to the packed section of the ion exchanger, a pump for adjusting the amount of polar organic solvent supplied to the packed section of the ion exchanger, and a supply device such as a relief valve for pressure control can be mentioned. Other examples of the polar organic solvent supply unit include a supply device that pressure-feeds the polar organic solvent contained in a pressure-feeding container by an inert gas, and a supply unit using a relief valve for pressure control.

In addition, in the polar organic solvent purification apparatus of the present invention, the polar organic solvent supplied to the ion exchanger packing section and purified may be circulated inside the purification apparatus immediately before use, immediately after use, or when unused. Therefore, the polar organic solvent purification apparatus of the present invention may have a circulation pipe that circulates the polar organic solvent supplied to the ion exchanger packing section and purified inside the purification apparatus, for example, a circulation pipe having one end connected to any position of the purified polar organic solvent discharge pipe on the discharge side of the ion exchanger packing section and the other end connected to any position of the polar organic solvent supply pipe on the supply side of the ion exchanger packing section.

In the polar organic solvent purification device of the present invention, the liquid-contacting parts of each component are preferably formed or coated with a fluororesin such as a copolymer of tetrafluoroethylene and perfluoroalkoxyethylene (PFA) or polytetrafluoroethylene (PTFE) in order to prevent metal elution. If there is no metal elution into the object to be removed or measured, the material of the liquid-contacting parts may be formed or coated with a mineral such as quartz.

In the method for purifying a polar organic solvent of the present invention and the method for producing a purified polar organic solvent of the present invention, water is added to the polar organic solvent to be treated in the water addition step, so that metal impurities are more easily ionized in the polar organic solvent and functional groups are more easily dissociated than in the case where water is not added, and the amount of ions removed by the ion exchange reaction is increased. In other words, in the method for purifying a polar organic solvent of the present invention and the method for producing a purified polar organic solvent of the present invention, by adding water to the polar organic solvent to be treated in the water addition step, the amount of functional groups that can be effectively used is increased, so that the life of the ion exchanger is longer than before the addition of water, and the replacement time can be delayed. Note that the higher the water content of the polar organic solvent, the easier it is to perform ion exchange, but as the concentration of the polar organic solvent decreases, the effect of using the polar organic solvent decreases, so the water content of the polar organic solvent after adding water in the water addition step is preferably 0.01 to 20.0 mass%, more preferably 0.01 to 10.0 mass%, and particularly preferably 0.10 to 5.0 mass%.

The analytical method of the present invention includes a water addition step of adding water to a polar organic solvent;
a purification step of contacting the polar organic solvent to which water has been added with an ion exchanger to obtain a purified polar organic solvent;
and a calibration curve preparation step of preparing a calibration curve using the purified polar organic solvent as a dilution solvent. That is, the analytical method of the present invention is an analytical method for quantitatively analyzing the metal content in a polar organic solvent, and includes at least a water addition step, a purification step, and a calibration curve preparation step.

The water addition step and purification step in the analytical method of the present invention are similar to the water addition step and purification step in the purification method of a polar organic solvent of the present invention.

The calibration curve preparation step in the analytical method of the present invention is a step of preparing a calibration curve using a purified polar organic solvent obtained by a purification step as a dilution solvent.

In the calibration curve preparation step, the purified polar organic solvent obtained by the purification step is used as a dilution solvent for preparing the calibration curve. In the calibration curve preparation step, the purified polar organic solvent is used as a dilution solvent to prepare a calibration curve. The standard solution is diluted with the purified polar organic solvent to prepare a plurality of diluted samples with different metal contents, and then each of the diluted samples is analyzed by the same analysis method as the method for performing quantitative analysis of an organic solvent whose content of each metal needs to be understood, and a calibration curve is prepared based on the obtained analysis results. For example, when performing quantitative analysis of an organic solvent whose content of each metal needs to be understood by the X analysis method, first, a standard solution of a known concentration is mixed with the purified polar organic solvent, and the standard solution is diluted with the purified polar organic solvent to prepare sample 1 diluted by a ₁ times, sample 2 diluted by a ₂ times, sample 3 diluted by a ₃ times, sample ₄ diluted by a ₄ times, and sample 5 diluted by a 5 times. Next, each of samples 1 to 5 is analyzed by the X analysis method, and a calibration curve is prepared by determining the relationship between the known concentration and the signal intensity of samples 1 to 5. The signal intensity differs depending on the analytical method, but in the case of ICP-MS, for example, the signal intensity for each mass-to-charge ratio of each ion can be obtained in a single measurement. The relationship between each mass of metal ion, a sample of known concentration, and the signal intensity is the calibration curve. The concentration can be calculated by applying the signal intensity of a sample of unknown concentration to the obtained calibration curve.

The standard solution used in the calibration curve creation process is a liquid that contains each metal to be analyzed and in which the content of each metal is accurately known, and is not particularly limited as long as it is a solution that can be used as a standard solution in creating a calibration curve for the quantitative analysis of impurities in a high-purity organic solvent.

In the analytical method of the present invention, after the calibration curve creation process, organic solvents in which the content of each metal needs to be determined, such as high-purity polar organic solvents for diluting low-polarity or non-polar organic solvents containing purified resists, polymers, pigments, etc., and polar organic solvents for drying purified wafers, etc., are analyzed, and the content of each metal in the organic solvent is determined using the created calibration curve.

Gas chromatography, liquid chromatography, ICP-MS (inductively coupled plasma mass spectrometry), ICP optical emission spectrometry, and atomic absorption spectrophotometry are used for quantitative analysis of organic solvents and for creating calibration curves.

The present invention will be described in detail below with reference to examples. However, the present invention is not limited to the following examples.

<Polar organic solvent 1 to be treated>
The oil-based standard solution Conoatan was added to semiconductor grade isopropyl alcohol (Tokuso IPA SE grade, manufactured by Tokuyama Corporation) to prepare polar organic solvent 1 to be treated, each of which had a metal concentration of 1 ppb. The water content of polar organic solvent 1 was 53 ppm by mass.

Example 1
Ultrapure water was added to polar organic solvent 1 to prepare a polar organic solvent having a water content of 95 ppm by mass.
Next, the polar organic solvent to which water had been added was passed through an H-type strongly acidic cation exchange resin (Orlite DS-1) at SV=5 h ⁻¹ for 4 hours to obtain a purified polar organic solvent after 4 hours of passing the liquid.
Next, the concentration of each metal in the purified polar organic solvent was measured using an ICP-MS Agilent 8900, and the removal rate of each metal element (removal rate (%)=((metal element concentration before purification−metal element concentration after purification)/metal element concentration before purification)×100) was calculated from the analytical values before and after the treatment. The results are shown in Table 1.
H-type strong acid cation exchange resin (DS-1): manufactured by Organo Corporation, cation exchange capacity 2.0 eq/L-resin

Example 2
A purified polar organic solvent was obtained in the same manner as in Example 1, except that ultrapure water was added to the polar organic solvent 1 to prepare a polar organic solvent having a water content of 193 ppm by mass. The results are shown in Table 1.

(Comparative Example 1)
The procedure of Example 1 was repeated except that water was not added to the polar organic solvent 1 to be treated, that is, the polar organic solvent passed through the H-type strongly acidic cation exchange resin (Orlite DS-1) was the polar organic solvent 1 to be treated, to obtain a purified polar organic solvent. The results are shown in Table 1.

<Polar organic solvent 2 to be treated>
Semiconductor grade isopropyl alcohol (Tokuso IPA SE grade, manufactured by Tokuyama Corporation) was prepared as the polar organic solvent 2 to be treated. The water content of the polar organic solvent 2 was 31 ppm by mass.

Example 3
Ultrapure water was added to the polar organic solvent 2 to prepare a polar organic solvent having a water content of 70 ppm by mass.
Next, the polar organic solvent to which water had been added was passed through a mixed bed of H-type strongly acidic cation exchange resin and OH-type anion exchange resin (Orlite DS-7) at SV=4 h ⁻¹ for 2 hours, and a purified polar organic solvent was obtained after 2 hours of passing the liquid.
Next, the concentration of each metal element in the purified polar organic solvent was measured using an ICP-MS Agilent 8900. The results are shown in Table 2.
Mixed bed of H-type strong acid cation exchange resin and OH-type anion exchange resin (DS-7): Organo Corporation, cation exchange resin exchange capacity 1.8 eq/L-resin, anion exchange resin exchange capacity 1.0 eq/L-resin

Example 4
A purified polar organic solvent was obtained in the same manner as in Example 3, except that ultrapure water was added to the polar organic solvent 2 to prepare a polar organic solvent having a water content of 170 ppm by mass, and the solution was passed through the polar organic solvent at SV = 8 h ^-1 for 1 hour. The results are shown in Table 2.

<Polar organic solvent 3 to be treated>
Propylene glycol monomethyl ether (PGME) containing high concentration of Na, with the respective metal element concentrations as shown in Table 3, was prepared as the polar organic solvent 3 to be treated. The water content of the polar organic solvent 3 was 154 ppm by mass.

Example 5
Ultrapure water was added to the polar organic solvent 3 to prepare a polar organic solvent having a water content of 320 ppm by mass.
Next, the polar organic solvent to which water had been added was passed through a double-bed ion exchanger having an upper layer of H-type strongly acidic cation exchange resin (Orlite DS-1) and a lower layer of a mixed bed of H-type strongly acidic cation exchange resin and OH-type strong anion exchange resin (DS-3) at SV=5 h ⁻¹ for 4 hours, and a purified polar organic solvent was obtained after 4 hours of passing the liquid.
Next, the concentration of each metal element in the purified polar organic solvent was measured using an ICP-MS Agilent 8900. The results are shown in Table 3.
Mixed bed of H-type strong acid cation exchange resin and OH-type anion exchange resin (DS-3): Organo Corporation, cation exchange resin exchange capacity 2.0 eq/L-resin, anion exchange resin exchange capacity 1.0 eq/L-resin

<Polar organic solvent 4 to be treated>
Propylene glycol monomethyl ether (PGME) containing high concentration of Na, with the respective metal element concentrations as shown in Table 3, was prepared as the polar organic solvent 4 to be treated. The water content of the polar organic solvent 4 was 141 ppm by mass.

(Comparative Example 2)
Without adding water to the polar organic solvent 4 to be treated, the polar organic solvent 4 was passed through a double-bed ion exchanger having an H-type strongly acidic cation exchange resin (Orlite DS-1) in an upper layer and a mixed bed of an H-type strongly acidic cation exchange resin and an OH-type strong anion exchange resin (DS-3) in a lower layer at SV = 5 h ^-1 for 4 hours, and a purified polar organic solvent was obtained after 4 hours of passing the liquid.
Next, the metal concentrations in the purified polar organic solvent were determined in the same manner as in Example 5. The results are shown in Table 3.

<Polar organic solvent 5 to be treated>
The oil-based standard solution Conoatan was added to semiconductor grade propylene glycol monomethyl ether acetate (PGMEA) to prepare polar organic solvent 5 to be treated, the metal concentrations of which were as shown in Table 4. The water content of polar organic solvent 5 was 51 ppm by mass.

Example 6
Ultrapure water was added to the polar organic solvent 5 to prepare a polar organic solvent having a water content of 92 ppm by mass.
Next, the polar organic solvent to which water had been added was passed through an H-type chelating exchange resin (Orlite DS-21) at SV=5 h ⁻¹ for 4 hours to obtain a purified polar organic solvent after 4 hours of passing the liquid.
Next, the concentration of each metal element in the purified polar organic solvent was measured using an ICP-MS Agilent 8900. The results are shown in Table 4.
H-type chelating exchange resin: H-type aminophosphate chelating resin (Organo Corporation, Orlite DS-21 (cation exchange capacity 1.8 eq/L-resin, harmonic mean diameter 500 μm))

(Comparative Example 3)
A purified polar organic solvent was obtained in the same manner as in Example 6, except that water was not added to the polar organic solvent 5 to be treated, that is, the polar organic solvent passed through the H-type chelating exchange resin (Orlite DS-21) was the polar organic solvent 5. The results are shown in Table 4.

(Example 7)
Water was added to semiconductor grade isopropyl alcohol (Tokuso IPA SE grade, manufactured by Tokuyama Corporation) to prepare isopropyl alcohol with water contents of 0.1 mass%, 1.0 mass%, 5.0 mass%, and 10.0 mass%, and then a metal standard solution was added to the isopropyl alcohol with each water content so that the metal impurity Na was 1 ppb. XSTC-13 (general-purpose mixed standard solution) manufactured by SPEX was used as the metal standard solution.
Next, the H-type strongly acidic cation exchange resin (DS-1) and isopropyl alcohol with each water content were placed in a beaker made of PFA (a copolymer of tetrafluoroethylene and perfluoroalkoxyethylene) in a mass ratio of 1:10, and the H-type strongly acidic cation exchange resin was immersed in the isopropyl alcohol with each water content for 1 hour or more to perform a metal adsorption batch test. Next, the metal concentration in the supernatant after the batch test was measured.
The amount of Na adsorption to the H-type strongly acidic cation exchange resin was calculated from the Na concentration in isopropyl alcohol before the batch test and the Na concentration in the supernatant after the batch test. In order to show the change in the amount of adsorption due to the difference in the water content of isopropyl alcohol, the amount of Na adsorption at each water content is shown in Table 5 and Figure 2, where the amount of Na adsorption at a water content of 10.0% by mass is taken as 100.

The results of the batch test confirmed that the amount of Na adsorption increased rapidly when the water content increased from 1.0% by mass to 5.0% by mass. In addition, when the water content was 5.0% by mass and 10.0% by mass, the amount of Na adsorption increased slightly, but the increase was small. In addition, since a large water content in the polar organic solvent may have a large effect on the accuracy of the analysis, it is preferable to maintain the concentration of the polar organic solvent at 80.0% by mass or more. Therefore, the water content of the polar organic solvent after adding water is preferably up to 20.0% by mass, and more preferably up to 10.0% by mass.

Claims (10)

a water addition step of adding water to the polar organic solvent;
a purification step of contacting the polar organic solvent to which water has been added with an ion exchanger to obtain a purified polar organic solvent in which ionic metal impurities have been reduced ;
having
the polar organic solvent is an alcohol or an ether compound, or a mixed solvent containing at least one of an alcohol and an ether compound;
The polar organic solvent contains at least one of Na, K, Li, Cr, As, Ca, Cu, Fe, Mg, Mn, Ni, Pb, and Zn as an ionic metal impurity,
the water content of the polar organic solvent before the addition of water is 200 ppm by mass or less, and the amount of water added to the polar organic solvent in the water addition step is 150 mass% or more as a ratio to the water content in the polar organic solvent before the addition of water ((amount of water added to the polar organic solvent/water content in the polar organic solvent before the addition of water)×100);
1. A method for purifying a polar organic solvent comprising the steps of: The method for purifying a polar organic solvent according to claim 1, characterized in that in the water addition step, water is added to the polar organic solvent in such a range that the water content in the polar organic solvent to which the water has been added is 0.01 to 20.0 mass%. 3. The method for purifying a polar organic solvent according to claim 1, wherein the ion exchanger is at least one of a cation exchanger, an anion exchanger and an H-type chelate exchanger. 4. The method for purifying a polar organic solvent according to claim 1, wherein the polar organic solvent is a solvent capable of dissolving 1.0 g or more of water per 100.0 g at 25° C. The method for purifying a polar organic solvent according to any one of claims 1 to 4 , wherein the purified polar organic solvent is a solvent used as a diluent in metal concentration analysis using ICP-MS. an ion exchanger packed section packed with an ion exchanger;
a water adding section for adding water to the polar organic solvent;
a polar organic solvent supplying section for supplying the polar organic solvent to which water has been added by the water adding section to the section packed with the ion exchanger;
6. An apparatus for purifying a polar organic solvent for carrying out the method for purifying a polar organic solvent according to any one of claims 1 to 5, comprising : 7. The apparatus for purifying a polar organic solvent according to claim 6 , wherein the liquid-contacting parts are formed of or coated with a fluorine-based resin. a water addition step of adding water to the polar organic solvent;
a purification step of contacting the polar organic solvent to which water has been added with an ion exchanger to obtain a purified polar organic solvent;
and creating a calibration curve by using the purified polar organic solvent as a dilution solvent ,
the polar organic solvent is an alcohol or an ether compound, or a mixed solvent containing at least one of an alcohol and an ether compound;
The method for analyzing a metal concentration using ICP-MS is characterized in that the polar organic solvent contains at least one of Na, K, Li, Cr, As, Ca, Cu, Fe, Mg, Mn, Ni, Pb, and Zn as an ionic metal impurity . a water addition step of adding water to the polar organic solvent;
a purification step of contacting the polar organic solvent to which water has been added with an ion exchanger to obtain a purified polar organic solvent in which ionic metal impurities have been reduced ;
having
the polar organic solvent is an alcohol or an ether compound, or a mixed solvent containing at least one of an alcohol and an ether compound;
The polar organic solvent contains at least one of Na, K, Li, Cr, As, Ca, Cu, Fe, Mg, Mn, Ni, Pb, and Zn as an ionic metal impurity,
the water content of the polar organic solvent before the addition of water is 200 ppm by mass or less, and the amount of water added to the polar organic solvent in the water addition step is 150 mass% or more as a ratio to the water content in the polar organic solvent before the addition of water ((amount of water added to the polar organic solvent/water content in the polar organic solvent before the addition of water)×100);
A method for producing a purified polar organic solvent, comprising: 10. The method for producing a purified polar organic solvent according to claim 9 , wherein the purified polar organic solvent is a diluent for metal concentration analysis using ICP-MS.

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