Method for removing salt in sample using solid phase extraction

Abstract

The present invention relates to a method for removing a salt in a sample using solid phase extraction, which is a salt removing method capable of facilitating analysis of a chelate or the like present in a sample, the method comprising the steps of: leaching a chelate from a sample, followed by centrifugation, thereby obtaining a primary supernatant; centrifuging the primary supernatant to obtain a secondary supernatant; and removing a salt of the secondary supernatant by solid phase extraction (SPE).

Description

Method for removing salt from a sample using solid phase extraction

[0001] The present invention relates to a method for removing salt from a sample using a solid phase extraction method.

[0002] Analyzing chelates in nuclear power plant decommissioning waste is a crucial technology required during the waste disposal process. According to the Korea Radioactive Waste Agency's acceptance standards, any chelating agent remaining at levels exceeding 0.1% must be identified by its chemical name and amount. However, because waste typically contains a variety of salts, analyzing chelating agents alone is difficult, requiring techniques to remove them.

[0003] In addition, the existing analytical methods applied to radioactive waste have technical limitations that make it difficult to specify the chemical name and abundance of multi-component chelating agents, and a chelating analysis method for various types of dismantled waste samples has not been secured, so new analytical technologies are urgently needed.

[0004] The problem to be solved by the present invention is to provide a method for removing salt from a sample using a solid phase extraction method so as to facilitate analysis of chelates, etc. present in the sample.

[0005] The present invention is a method for removing salts from a sample using a solid phase extraction method, comprising the steps of: leaching a chelate from a sample, centrifuging the sample to obtain a first supernatant; centrifuging the first supernatant to obtain a second supernatant; and removing salts from the second supernatant using a solid phase extraction (SPE) method.

[0006] In the present invention, the step of extracting chelate from the sample and centrifuging to obtain a first supernatant may include the steps of adding 1 to 50 mL of distilled water per 1 g of sample and extracting using ultrasonic waves for 0.5 to 2 hours; and centrifuging at 5,000 to 12,000 g for 5 to 20 minutes to obtain a first supernatant.

[0007] In the present invention, the step of centrifuging the first supernatant to obtain a second supernatant comprises the steps of: adding NaOH to the first supernatant to adjust the pH to 10 or higher; centrifuging the first supernatant at 5,000 to 12,000 g for 5 to 20 minutes to obtain a second supernatant; adding Ni(NO3)2 to the second supernatant. The method may include a step of adding HCl to the second supernatant to adjust the pH to 6 to 7; and a step of heating the second supernatant at 50 to 70° C. for 1 to 3 hours.

[0008] In the present invention, the NaOH may have a concentration of 0.05 to 1 N.

[0009] In the present invention, the HCl may have a concentration of 0.05 to 1 M.

[0010] In the present invention, the step of removing the salt of the secondary supernatant by solid phase extraction (SPE) may include the steps of: preparing a sample by adding acetonitrile in a volume 0.5 to 2 times the volume of the secondary supernatant; injecting a solvent into a cartridge; injecting a sample into the cartridge; washing the cartridge by injecting the solvent and depressurizing it; and eluting by injecting (NH4)HCO3 at a concentration of 0.1 to 0.5 M.

[0011] In the present invention, the solvent may be a mixed solvent containing distilled water and acetonitrile.

[0012] In the present invention, the cartridge comprises an adsorbent NH2(Aminopropyl) Or it could be a cartridge that is Primary Secondary Amine (PSA).

[0013] In the present invention, the sample may be soil or radioactive waste.

[0014] In the present invention, the diameter of the sample may be 0.25 mm or less.

[0015] In the present invention, the sample is pretreated, and the pretreatment may include a step of first drying the sample at 20 to 60°C for 12 to 36 hours; a step of second drying the sample at 90 to 120°C for 6 to 24 hours after uniformly dissolving clumped samples among the first dried samples; a step of pulverizing the second dried sample to a diameter of 2 mm or less; a step of obtaining a sample of 50 to 100 g by repeating the cone-quartering method; and a step of pulverizing the sample to a diameter of 0.25 mm or less.

[0016] The present invention provides a method for easily removing salt from a sample, thereby enabling easy chelate analysis of various types of samples.

[0017] Additionally, by removing salt, the life of the device can be increased and analysis at low concentrations can be facilitated.

[0018] Figure 1 shows the HPLC-PDA results of Example 1 and Comparative Example.

[0019] Figure 2 shows the HPLC-PDA results of Example 2 and Comparative Example.

[0020] Hereinafter, the present invention will be described in more detail with reference to exemplary embodiments, examples, etc. so that those skilled in the art can easily implement the present invention. However, the present invention may be implemented in various different forms and is not limited to the embodiments, examples, etc. described herein.

[0021] Additionally, when the terms "about," "approximately," or similar expressions such as "at least" are used in connection with a numerical value in the present invention, it is intended that a theoretical, experimental, statistical, or empirical error of ±10%, ±7%, ±5%, ±3%, ±2%, or ±1% based on the numerical value is allowed.

[0022]

[0023] The present invention is a method for removing salts from a sample using a solid phase extraction method, comprising the steps of: leaching a chelate from a sample, centrifuging the sample to obtain a first supernatant; centrifuging the first supernatant to obtain a second supernatant; and removing salts from the second supernatant using a solid phase extraction (SPE) method.

[0024] In the present invention, the step of extracting chelate from the sample and centrifuging to obtain a first supernatant is a step of extracting chelate from the sample in order to analyze the chelate.

[0025] The step of extracting chelate from the above sample and centrifuging to obtain a first supernatant may include a step of adding 1 to 50 mL of distilled water per 1 g of sample and ultrasonically extracting for 0.5 to 2 hours; and a step of centrifuging at 5,000 to 12,000 g for 5 to 20 minutes to obtain a first supernatant.

[0026] The step of adding 1 to 50 mL of distilled water per 1 g of the sample and ultrasonically leaching for 0.5 to 2 hours may be preferably a step of adding 5 to 15 mL of distilled water per 1 g of the sample and ultrasonically leaching for 0.8 to 1.2 hours, and leaching can proceed easily under the above conditions.

[0027] The above centrifugation can be performed at 5,000 to 12,000 g for 5 to 20 minutes, preferably at 6,000 to 10,000 g for 8 to 12 minutes, and separation of the supernatant can be easily performed under the above conditions.

[0028] In the present invention, the step of centrifuging the first supernatant to obtain a second supernatant is a step of separating a precipitate from the solution and obtaining a Ni chelate.

[0029] The step of centrifuging the first supernatant to obtain a second supernatant includes: a step of adjusting the pH to 10 or higher by adding NaOH to the first supernatant; a step of centrifuging the first supernatant at 5,000 to 12,000 g for 5 to 20 minutes to obtain a second supernatant; and a step of adding Ni(NO3)2 to the second supernatant. The method may include a step of adding HCl to the second supernatant to adjust the pH to 6 to 7; and a step of heating the second supernatant at 50 to 70° C. for 1 to 3 hours.

[0030] The step of adjusting the pH to 10 or higher by adding NaOH to the first supernatant is a step for precipitating a metal by adjusting the pH to 10 or higher, and NaOH may be added to the first supernatant, and the NaOH may have a concentration of 0.05 to 1 N.

[0031] The step of centrifuging the first supernatant at 5,000 to 12,000 g for 5 to 20 minutes and obtaining the second supernatant is a step for removing sediment, and centrifugation can preferably be performed at 6,000 to 10,000 g for 8 to 12 minutes, and separation of the supernatant can be easily performed under the above conditions.

[0032] Ni(NO3)2 in the above second supernatant The step of adding is a step for forming a chelate and complex with an excess of Ni (nickel). Ni (NO3)2 can be added in an amount of 0.5 to 5 mL per 3 mL of the secondary supernatant, and the concentration of the Ni (NO3)2 can be 10 to 20 M, and under the above conditions, complex formation between Ni and the chelate can easily proceed.

[0033] In the step of adjusting the pH to 6 to 7 by adding HCl to the secondary supernatant, the HCl may have a concentration of 0.05 to 1 M, and under the above conditions, complex formation between Ni and the chelate may easily proceed.

[0034] In the present invention, the step of removing the salt of the secondary supernatant using solid phase extraction (SPE) is a step for removing the salt peak that appears during analysis in order to analyze the chelate contained in the sample.

[0035] The step of removing the salt of the secondary supernatant using solid phase extraction (SPE) may include the steps of preparing a sample by adding acetonitrile in a volume 0.5 to 2 times the volume of the secondary supernatant; injecting a solvent into a cartridge; injecting a sample into the cartridge; washing the cartridge by injecting the solvent and depressurizing it; and eluting by injecting (NH4)HCO3 at a concentration of 0.1 to 0.5 M.

[0036] In the step of preparing a sample by adding acetonitrile in an amount of 0.5 to 2 times the volume of the secondary supernatant, preferably, the acetonitrile can be added in an amount equal to the volume of the secondary supernatant.

[0037] The step of injecting the solvent into the cartridge is a step to prevent the cartridge from drying out before loading the sample, and the solvent may be a mixed solvent containing distilled water and acetonitrile. The mixed solvent may contain distilled water and acetonitrile in a volume ratio of 1:0.5 to 2, and preferably in a volume ratio of 1:1.

[0038] In the step of injecting the sample into the cartridge, the injection amount of the sample may vary depending on the situation.

[0039] In the step of injecting a solvent into the above cartridge to wash and depressurize, the depressurization can be performed until all of the solvent injected for washing comes out.

[0040] Thereafter, in the step of eluting by injecting (NH4)HCO3 at a concentration of 0.1 to 0.5 M, the concentration of (NH4)HCO3 may preferably be 0.1 to 0.2 M.

[0041] The above cartridge contains NH2(Aminopropyl) as the adsorbent. Or it could be a cartridge that is Primary Secondary Amine (PSA).

[0042] Solid phase extraction can be performed under the above conditions, and salt removal can be facilitated under the above conditions.

[0043] In the present invention, the sample may be soil or radioactive waste, but is not limited thereto, and the present invention can be performed to remove salt from various samples.

[0044] In the present invention, the diameter of the sample may be 0.25 mm or less, and if the diameter of the sample exceeds 0.25 mm, salt removal may not be easy.

[0045] In the present invention, the sample may be pretreated, and the pretreatment may include a step of first drying the sample at 20 to 60°C for 12 to 36 hours; a step of second drying the sample at 90 to 120°C for 6 to 24 hours after uniformly dissolving clumped samples among the first dried samples; a step of pulverizing the second dried sample to a diameter of 2 mm or less; a step of obtaining a sample of 50 to 100 g by repeating the cone-quartering method; and a step of pulverizing the sample to a diameter of 0.25 mm or less.

[0046] In the present invention, diameter means the longest distance based on the center of the sample.

[0047] In the present invention, the sample is pretreated so that various samples can be made suitable for the salt removal method according to the present invention, and by being pretreated, storage properties can be increased and management can be made easy.

[0048] Hereinafter, specific examples according to the present invention will be described.

[0049]

[0050] Manufacturing example: Sample preparation

[0051] The soil was collected from 0 to 15 cm above the ground surface at five points in a zigzag pattern over a 3 m x 3 m area of ​​the target area.

[0052] The collected soil is dried at approximately 40°C for approximately 24 hours after removing any remaining grass roots. Afterwards, any clumps of the primary dried samples are evenly dispersed and dried a second time at approximately 105°C for approximately 12 hours.

[0053] Afterwards, the secondary dried soil is sieved using a 2 mm sieve, and particles larger than 2 mm are crushed to less than 2 mm using a mixer, mortar, etc. Afterwards, the cone-quartering method is repeated to obtain a sample weighing 50 to 100 g. The cone-quartering method is as follows.

[0054] 1) Mix the samples and stack them in a cone shape. 2) Flatten the cone-shaped stack by pressing vertically from the top. 3) Divide the flattened sample into four equal parts and discard one of the two diagonal sections. 4) Repeat steps 1) through 3) until the desired sample volume is reached.

[0055] Afterwards, prepare the sample by crushing the sample to a diameter of 0.25 mm or less.

[0056]

[0057] Example 1

[0058] Add 10 mL of triple-distilled water to 1 g of the sample prepared in the manufacturing example and extract in a sonic bath (sonic bath, 3510-DTH) for 1 hour. Afterwards, separate the supernatant and the sample using a centrifuge (8000 g, 10 minutes), and collect the first supernatant.

[0059] Add about 50 μL of 0.1 N NaOH per 5 mL of the first supernatant to adjust the pH to about 10 or higher.

[0060] Afterwards, the first supernatant with added NaOH is separated using a centrifuge (8000 g, 10 minutes) to obtain the second supernatant. Add 1 mL of 16 M Ni(NO3)2 per 3 mL of the second supernatant. Then, add about 50 μL of 0.01 M HCl to adjust the pH to 6.5±0.2. Then, heat at about 60°C for 2 hours.

[0061] A sample is prepared by adding an equal volume of acetonitrile to the heated secondary supernatant.

[0062] Afterwards, conditioning is performed by injecting 5 mL of a mixed solvent of distilled water and acetonitrile in a volume ratio of 1:1 into a solid phase extraction cartridge (Sep-Pak-PSA (Primary Secondary Amine)) with PSA (Primary Secondary Amine) as the adsorbent.

[0063] Next, after injecting 5 mL of the manufactured sample, the cartridge is washed with 5 mL of a mixed solvent, and then dried under reduced pressure for 3 minutes to remove the solvent inside the cartridge and remove the salt.

[0064] Afterwards, the complex is recovered by eluting it by injecting 10 mL of (NH4)HCO3 at a concentration of 0.1 M.

[0065]

[0066] Example 2

[0067] Add 10 mL of triple-distilled water to 1 g of the sample prepared in the manufacturing example and extract in a sonic bath (sonic bath, 3510-DTH) for 1 hour. Afterwards, separate the supernatant and the sample using a centrifuge (8000 g, 10 minutes), and collect the first supernatant.

[0068] Add about 50 μL of 0.1 N NaOH per 5 mL of the first supernatant to adjust the pH to about 10 or higher.

[0069] Afterwards, the first supernatant with added NaOH is separated using a centrifuge (8000 g, 10 minutes) to obtain the second supernatant. Add 1 mL of 16 M Ni(NO3)2 per 3 mL of the second supernatant. Then, add about 50 μL of 0.01 M HCl to adjust the pH to 6.5±0.2. Then, heat at about 60°C for 2 hours.

[0070] A sample is prepared by adding an equal volume of acetonitrile to the heated secondary supernatant.

[0071] Afterwards, conditioning is performed by injecting 5 mL of a mixed solvent of distilled water and acetonitrile in a volume ratio of 1:1 into a solid phase extraction cartridge (Sep-Pak-Aminopropyl(NH2)) with NH2(Aminopropyl) as the adsorbent.

[0072] Next, after injecting 5 mL of the manufactured sample, the cartridge is washed with 5 mL of a mixed solvent, and then dried under reduced pressure for 3 minutes to remove the solvent inside the cartridge and remove the salt.

[0073] Afterwards, the complex is recovered by eluting it by injecting 10 mL of (NH4)HCO3 at a concentration of 0.1 M.

[0074]

[0075] Comparative example

[0076] Add 10 mL of triple-distilled water to 1 g of the sample prepared in the manufacturing example and extract in a sonic bath (sonic bath, 3510-DTH) for 1 hour. Afterwards, separate the supernatant and the sample using a centrifuge (8000 g, 10 minutes), and collect the first supernatant.

[0077] Add about 50 μL of 0.1 N NaOH per 5 mL of the first supernatant to adjust the pH to about 10 or higher.

[0078] Afterwards, the first supernatant with added NaOH is separated using a centrifuge (8000 g, 10 minutes) to obtain the second supernatant. Add 1 mL of 16 M Ni(NO3)2 per 3 mL of the second supernatant. Then, add about 50 μL of 0.01 M HCl to adjust the pH to 6.5±0.2. Afterwards, heat at about 60°C for 2 hours and cool to room temperature.

[0079]

[0080] Experimental example

[0081] Chelate analysis was performed using HPLC-PDA. Shimadzu Nexera was used for HPLC-PDA, and the conditions are as shown in Table 1 below, and the results are shown in Figure 1.

[0082] The column used was XBridge BEH Amide column; 5 μm; 4.6 * 250 mm, and the guard column used XBridge BEH Amide VanGuard Cartridge. 10 mM (NH4)HCO3, pH adjusted to 8.50±2 with ammonia water, was used as mobile phase solvent A, and 0.1 M NH4HCO3:ACN = 1:9 was mixed and used as mobile phase solvent B.

[0083]

[0084] Time (min)Mobile phase solvent AMobile phase solvent B00100104060154060200100350100Column temperature: 50℃Auto sampler temperature: 10℃Flow rate: 1 mL / minInjection volume: 10 ㎕Wavelength: 224 nm

[0085] Figure 1 shows the HPLC-PDA results of Example 1 and Comparative Example, and Figure 2 shows the HPLC-PDA results of Example 2 and Comparative Example.

[0086] Referring to FIGS. 1 and 2, it can be confirmed that when salt is removed according to the present invention (Examples 1 and 2), the salt peak is removed more than when salt is not removed (Comparative Example), and the peak of the chelate is similar to when salt is not removed.

[0087] The present invention provides a method for easily removing salt from a sample, thereby enabling easy chelate analysis of various types of samples.

[0088] Additionally, by removing salt, the life of the device can be increased and analysis at low concentrations can be facilitated.

Claims

1. A step of leaching chelate from a sample and centrifuging to obtain a first supernatant; A step of centrifuging the first supernatant to obtain a second supernatant; and A step of removing salt from the secondary supernatant using solid phase extraction (SPE); A method for removing salt from a sample using a solid phase extraction method, including:

2. In paragraph 1, The step of leaching the chelate from the above sample and centrifuging to obtain the first supernatant is as follows: A step of adding 1 to 50 mL of distilled water per 1 g of sample and ultrasonic leaching for 0.5 to 2 hours; and A step of centrifuging at 5,000 to 12,000 g for 5 to 20 minutes and obtaining the first supernatant; A method for removing salt from a sample using a solid phase extraction method, comprising:

3. In paragraph 1, The step of centrifuging the first supernatant to obtain the second supernatant is as follows: A step of adjusting the pH to 10 or higher by adding NaOH to the first supernatant; A step of centrifuging the first supernatant at 5,000 to 12,000 g for 5 to 20 minutes and obtaining the second supernatant; Ni(NO3)2 in the above second supernatant Step of adding; A step of adjusting the pH to 6-7 by adding HCl to the above secondary supernatant; and A step of heating the above secondary supernatant at 50 to 70 ℃ for 1 to 3 hours; A method for removing salt from a sample using a solid phase extraction method, comprising:

4. In paragraph 3, A method for removing salt from a sample using a solid phase extraction method, wherein the above NaOH has a concentration of 0.05 to 1 N.

5. In paragraph 3, A method for removing salt from a sample using a solid phase extraction method, wherein the above HCl has a concentration of 0.05 to 1 M.

6. In paragraph 1, The step of removing the salt of the above secondary supernatant using solid phase extraction (SPE) is as follows: A step of preparing a sample by adding acetonitrile in an amount of 0.5 to 2 times the volume of the secondary supernatant; Step of injecting the solvent into the cartridge; Step of injecting the sample into the cartridge; A step of injecting a solvent into the cartridge to wash it and depressurize it; and A step of eluting by injecting (NH4)HCO3 at a concentration of 0.1 to 0.5 M; A method for removing salt from a sample using a solid phase extraction method, comprising:

7. In paragraph 6, A method for removing salt from a sample using a solid phase extraction method, wherein the solvent is a mixed solvent containing distilled water and acetonitrile.

8. In paragraph 6, The above cartridge contains NH2(Aminopropyl) as the adsorbent. A method for removing salt from a sample using a solid phase extraction method, wherein the cartridge is a PSA (Primary Secondary Amine).

9. In paragraph 1, A method for removing salt from a sample using a solid phase extraction method, wherein the sample is soil or radioactive waste.

10. In paragraph 1, A method for removing salt from a sample using a solid phase extraction method, wherein the diameter of the sample is 0.25 mm or less.

11. In paragraph 1, The above sample is pretreated, The above preprocessing is, A step of primary drying the sample at 20 to 60 ℃ for 12 to 36 hours; A step of evenly dispersing clumped samples from the first dried samples and then drying them for a second time at 90 to 120°C for 6 to 24 hours; A step of grinding the secondary dried sample into pieces with a diameter of 2 mm or less; A step of obtaining a sample of 50 to 100 g by repeating the cone-four method; and A step of grinding the sample to a diameter of 0.25 mm or less; A method for removing salt from a sample using a solid phase extraction method, comprising:

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