Method for detecting halogen in paper printed matter based on oxygen bomb combustion-ion chromatography

Abstract

The invention relates to the technical field of chemical analysis and detection, in particular to a method for detecting halogen in a paper printed matter based on oxygen bomb combustion-ion chromatography. The detection method comprises the following steps: placing a folded to-be-detected paper printed matter in an oxygen bomb device, introducing oxygen, and combusting to obtain a to-be-detected liquid; a strong alkali solution is added into an oxygen bomb combustion cavity of the oxygen bomb device; a hydrogen peroxide solution is added into the absorption cup; and carrying out ion chromatography detection on the to-be-detected liquid, and obtaining the content of halogen in the to-be-detected paper printed matter according to the detected peak area of halogen and a preset standard curve. The combustion area is increased by folding the sample, the combustion efficiency is improved, oxygen is supplied through the hydrogen peroxide solution, and sufficient combustion of the sample is ensured; cO2 is absorbed by using a strong alkali solution, the pressure of the cavity is reduced, and the operation safety is improved; and then microgram / kg-level detection is realized by utilizing an ion chromatography method.

Description

Technical Field

[0002] This invention relates to the field of chemical analysis and detection technology, specifically to a method for detecting halogens in printed paper based on oxygen bomb combustion-ion chromatography. Background Technology

[0003] Fluorine, chlorine, and bromine, among the halogen elements, are chemically reactive and widely used in printing coatings. However, because the halogens released from coatings can affect the human respiratory system, the content of halogens and their compounds has been restricted in materials containing halogens in recent years.

[0004] Halogen detection methods generally involve sample processing followed by ion chromatography. Sample processing methods include high-temperature hydrolysis, oxygen bomb combustion, high-temperature roasting, alkali fusion, catalytic digestion, and ultraviolet decomposition. The most common method is oxygen bomb combustion, where the sample is placed in the combustion chamber. To minimize error, this method requires a small sample volume, making it unsuitable for large surface area, low-density samples (such as paper and printed materials). Furthermore, with large surface area, low-density samples, oxygen bomb combustion can lead to incomplete combustion due to insufficient oxygen, resulting in incomplete halogen release and excessively high chamber pressure due to CO2 accumulation. Therefore, traditional methods require multiple samplings, are complex, and lack sufficient accuracy, failing to meet the detection requirements for low-content halogens. Summary of the Invention

[0005] The purpose of this invention is to provide a method for detecting halogens in paper printed materials based on oxygen bomb combustion-ion chromatography. The detection method provided by this invention can accurately detect the halogen content in samples with large surface area and low density, and can also achieve the detection of low concentrations of halogens.

[0006] To achieve the above objectives, the present invention provides the following technical solution: This invention provides a method for detecting halogens in printed paper based on oxygen bomb combustion-ion chromatography, comprising the following steps: (1) Place the folded paper to be tested in the oxygen bomb device, introduce oxygen, and burn it to obtain the test liquid; add a strong alkaline solution to the oxygen bomb combustion chamber of the oxygen bomb device; add hydrogen peroxide solution to the absorption cup. (2) The test solution is subjected to ion chromatography. Based on the peak area of ​​the halogen obtained from the detection and the predetermined standard curve, the halogen content in the paper printed matter to be tested is obtained.

[0007] Preferably, the strong alkaline solution is a saturated sodium hydroxide solution.

[0008] Preferably, the concentration of the hydrogen peroxide solution is 25-30 wt.%.

[0009] Preferably, the halogen is one or more of fluorine, chlorine and bromine.

[0010] Preferably, the chromatographic column used for ion chromatography detection is a Dionex IonPac AS23 anion exchange column.

[0011] Preferably, the mobile phase for ion chromatography detection is a mixed solution of Na2CO3 and NaHCO3.

[0012] Preferably, the concentration of Na2CO3 in the mixed solution is 0.1M; and the concentration of NaHCO3 solution in the mixed solution is 0.07M.

[0013] Preferably, the pressure at which oxygen is introduced into the oxygen bomb combustion chamber is 1.5~2.0 MPa.

[0014] Preferably, after combustion, the process further includes rinsing the absorption cup, and the resulting rinsing solution is combined with the absorption solution in the absorption cup.

[0015] This invention increases the combustion area and improves combustion efficiency by folding the sample, and ensures complete combustion of the sample by supplying oxygen with hydrogen peroxide solution; it also uses a strong alkaline solution to absorb CO2, reduce chamber pressure, and improve operational safety; and then uses ion chromatography to detect low-content samples (μg / kg level). Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 Standard curves for halogens fluorine, chlorine, and bromine; Figure 2 This is the ion chromatogram of halogens after the paper sample was burned. Detailed Implementation

[0018] This invention provides a method for detecting halogens in printed paper based on oxygen bomb combustion-ion chromatography, comprising the following steps: (1) Place the folded paper to be tested in the oxygen bomb device, introduce oxygen, and burn it to obtain the test liquid; add a strong alkaline solution to the oxygen bomb combustion chamber of the oxygen bomb device; add hydrogen peroxide solution to the absorption cup. (2) The test solution is subjected to ion chromatography. Based on the peak area of ​​the detected halogen and the predetermined standard curve, the halogen content in the paper printed matter to be tested is obtained. In one embodiment of the present invention, the strong alkaline solution may be a saturated sodium hydroxide solution; In one embodiment of the present invention, the concentration of the hydrogen peroxide solution can be 25-30 wt.%.

[0019] In one embodiment of the present invention, the chromatographic column used for ion chromatography detection is a Dionex IonPac AS23 anion exchange column; the mobile phase can be a mixed solution of Na2CO3 and NaHCO3; the concentration of Na2CO3 in the mixed solution can be 0.1M; and the concentration of NaHCO3 in the mixed solution can be 0.07M.

[0020] In one embodiment of the present invention, the pressure at which oxygen is introduced into the oxygen bomb combustion chamber can be 1.5~2 MPa. In another embodiment of the present invention, to ensure that there are no other gases in the oxygen bomb combustion chamber, it is preferable to release the pressure after introducing oxygen to 1.5~2 MPa, and repeat this process 2~3 times.

[0021] In one embodiment of the present invention, after combustion, the absorption cup is further rinsed, and the resulting rinsing solution is combined with the absorption solution in the absorption cup.

[0022] In one embodiment of the present invention, in order to improve the detection accuracy, it is preferable to test 3 times and take the average value as the final result.

[0023] In one embodiment of the present invention, the predetermined standard curve is obtained as follows: Prepare a series of standard solutions of halide ions with different concentrations; The halogen ion standard solutions are detected by ion chromatography, and the predetermined standard curve is obtained by linear fitting based on the concentration and peak area of ​​halogen in each halogen solution.

[0024] To further illustrate the present invention, the following detailed description of the invention's solutions, in conjunction with the accompanying drawings and embodiments, is provided, but should not be construed as limiting the scope of protection of the present invention.

[0025] Example 1 Sample preparation: Cut a 400 cm sample 2 The paper print to be tested was folded to 3 cm. 2 It is fixed to the oxygen bomb combustion wire; Oxygen bomb assembly: Inject 15 mL of saturated sodium hydroxide solution (52 wt.%) into the oxygen bomb combustion chamber, add 30 wt.% hydrogen peroxide solution to the absorption cup, place it in the oxygen bomb combustion chamber, and screw on the oxygen bomb cap; Oxygen charging and ignition: Place the oxygen bomb on the oxygenator and open the main oxygen valve. Adjust the pressure reducing valve to 1.5 MPa, press down the handle, and wait for the oxygen pressure gauge on the oxygenator to stop, indicating that oxygen charging is complete. Then, use the pressure relief valve to release the gas from the oxygen bomb combustion chamber and charge oxygen again. Repeat this process three times. Fill the cooling tank with 3000 mL of cooling water, place the oxygen bomb combustion chamber in it, connect the ignition wire, turn on the ignition controller power, and press the ignition switch.

[0026] After the oxygen bomb combustion chamber has cooled down, remove it, wipe the outer surface dry, unscrew the ignition wire, put 20 mL of deionized water into the external absorption bottle as the absorption liquid, connect the exhaust pipe, and slowly exhaust the air until no bubbles overflow; open the oxygen bomb cap, take out the absorption cup, rinse the absorption cup and the inner wall of the oxygen bomb combustion chamber with ultrapure water, recover the rinsing liquid, and quantitatively measure the absorption liquid (hydrogen peroxide solution, sodium hydroxide saturated solution and deionized water absorption liquid) and rinsing liquid into a 100 mL volumetric flask to obtain the test solution; The test solution is subjected to ion chromatography for detection. Based on the peak area of ​​the detected halogen and the predetermined standard curve, the halogen content in the paper printed matter is obtained. The chromatographic analysis detected by the ion chromatography method used a mixed solution of 0.1M Na2CO3 and 0.07M NaHCO3 as the mobile phase and a Dionex IonPac AS23 anion exchange column as the chromatographic column. The predetermined standard curve is obtained as follows: The 1000 mg / L chloride ion standard solution, fluoride ion standard solution and bromide ion standard solution were diluted to 0.05 mg / L, 0.1 mg / L, 0.2 mg / L, 0.5 mg / L and 1 mg / L respectively to obtain a series of standard solutions for each halogen; A series of standard solutions of each halogen were detected by ion chromatography. Based on the peak area and concentration of each halogen, a linear fit was performed to obtain the predetermined standard curve. The predetermined standard curve for fluorine halogen was Y=0.0538X; the predetermined standard curve for chlorine was Y=0.0391X; and the predetermined standard curve for bromine was Y=0.0166X.

[0027] Comparative Example 1 Sample preparation: Cut a 400 cm sample 2 The paper print to be tested was folded to 3 cm. 2 ; Oxygen bomb assembly: Fix the sample with the combustion wire, add 20 mL of ultrapure water to the absorption cup, place it in the oxygen bomb combustion chamber, and screw on the oxygen bomb cap; Oxygen charging and ignition: Place the oxygen bomb on the oxygenator and open the main oxygen valve. Adjust the pressure reducing valve to 1.5 MPa, press down the handle, and wait for the oxygen pressure gauge on the oxygenator to stop, indicating that the oxygen charging is complete. Then, use the pressure relief valve to release the gas from the oxygen bomb combustion chamber and charge it again. Repeat this process 3 times. Fill the cooling tank with 3000 mL of cooling water, place the oxygen bomb combustion chamber in it, connect the ignition wire, turn on the ignition controller power, and press the ignition switch. Absorbent treatment: After the oxygen bomb combustion chamber has cooled down, remove it, wipe the outer surface dry, unscrew the ignition wire, put 20mL of deionized water into the external absorption bottle as the absorbent, connect the exhaust pipe, and slowly exhaust the air until no bubbles overflow; open the oxygen bomb cap, take out the absorption cup, rinse the absorption cup and the inner wall of the oxygen bomb combustion chamber with ultrapure water, recover the rinsing solution, and quantitatively measure the absorbent and rinsing solution into a 100mL volumetric flask to obtain the test solution; Ion chromatography analysis: A mixed solution of 0.1M Na₂CO₃ and 0.07M NaHCO₃ was used as the mobile phase, and a Dionex IonPac AS23 anion exchange column was used. Repeatability: The test was repeated three times, and the contents of chlorine, fluorine, and bromine were calculated according to the predetermined standard curve given in Example 1. The test results of Example 1 and Comparative Example 1 are shown in Table 1.

[0028] Table 1 Test results of Example 1 and Comparative Example 1

[0029] Table 1 shows that compared with sodium hydroxide and hydrogen peroxide absorption solutions, the halogen detection results in printed materials were lower when the absorption solution was ultrapure water, and the repeatability of the samples was poor. Observation of the combustion products revealed that the printed materials were not completely burned, and the degree of incomplete combustion varied each time, confirming that when ultrapure water was used as the absorption liquid, external oxygenation could not meet the oxygen demand of the printed materials during combustion.

[0030] Hydrogen peroxide absorbent solution is added to the combustion chamber of the oxygen bomb. During the initial combustion of the printed material, oxygen is supplied externally. Once the chamber temperature reaches above 60°C, the hydrogen peroxide begins to decompose, producing oxygen and water, providing the oxygen needed for the later stages of combustion. Simultaneously, if the CO2 produced by the combustion is not absorbed quickly enough, it may cause suffocation within the chamber, leading to combustion cessation. A saturated sodium hydroxide solution absorbs approximately 20 times more carbon dioxide than water. By absorbing CO2 within the chamber, the sodium hydroxide solution ensures a sufficient supply of oxygen and complete combustion of the printed material.

[0031] Although the above embodiments have provided a detailed description of the present invention, they are only some embodiments of the present invention, and not all embodiments. Other embodiments can be obtained based on these embodiments without creative effort, and these embodiments all fall within the protection scope of the present invention.

Claims

1. A method for detecting halogens in printed paper based on oxygen bomb combustion-ion chromatography, characterized in that, Includes the following steps: (1) Place the folded paper to be tested in the oxygen bomb device, introduce oxygen, and burn it to obtain the test liquid; add a strong alkaline solution to the oxygen bomb combustion chamber of the oxygen bomb device; add hydrogen peroxide solution to the absorption cup. (2) The test solution is subjected to ion chromatography. Based on the peak area of ​​the halogen obtained from the detection and the predetermined standard curve, the halogen content in the paper printed matter to be tested is obtained.

2. The detection method as described in claim 1, characterized in that, The strong alkaline solution is a saturated sodium hydroxide solution.

3. The detection method as described in claim 1, characterized in that, The concentration of the hydrogen peroxide solution is 25-30 wt.%.

4. The detection method as described in claim 1, characterized in that, The halogen is one or more of fluorine, chlorine and bromine.

5. The detection method as described in claim 1, characterized in that, The chromatographic column used for ion chromatography detection was a Dionex IonPac AS23 anion exchange column.

6. The detection method as described in claim 1, characterized in that, The mobile phase for ion chromatography detection is a mixed solution of Na2CO3 and NaHCO3.

7. The detection method as described in claim 6, characterized in that, The concentration of Na2CO3 in the mixed solution of Na2CO3 and NaHCO3 is 0.1M; the concentration of NaHCO3 solution in the mixed solution is 0.07M.

8. The detection method as described in claim 1, characterized in that, The pressure at which oxygen is introduced into the oxygen bomb combustion chamber is 1.5~2.0 MPa.

9. The detection method as described in claim 1, characterized in that, After combustion, the process also includes rinsing the absorption cup, and the resulting rinsing solution is combined with the absorption solution in the absorption cup.

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