Qualitative detection method for AKD (alkyl ketene dimer) and ASA (acrylonitrile styrene acrylate) sizing agents in paper products

Abstract

The invention provides a qualitative detection method for AKD and ASA sizing agents in a paper product. The method comprises the following steps: (1) treating a sample; (2) preparing a test sample; (3) preparing a comparison sample; and (4) carrying out thermal cracking-gas chromatography-mass spectrometry combined detection. According to the present invention, the AKD and the ASA in the paper product are qualitatively determined by using the thermal cracking-gas chromatography-mass spectrometry combined method through the research, the paper sample is directly placed in the pyrolysis instrument connected with the gas chromatograph, the cellulose is completely decomposed into the volatile substance at the high temperature, the reacted sizing agent and the unreacted sizing agent in the paper product are released, and the paper product is subjected to the thermal cracking-gas chromatography-mass spectrometry combined method, and whether the paper product contains the sizing agents such as AKD and ASA or not can be qualitatively analyzed according to test data of a gas chromatography-mass spectrometer. The technical scheme is simple, rapid and low in cost, and provides a reliable basis for paper identification and fiber source analysis.

Description

Technical Field

[0001] This invention relates to the field of analytical testing technology, and in particular to a qualitative detection method for AKD and ASA sizing agents in paper products. Background Technology

[0002] AKD (alkyl ketene dimer) and ASA (alkenyl succinic anhydride), as mainstream neutral / alkaline reactive sizing agents (reactive neutral sizing agents), have a core sizing mechanism that involves esterification with the hydroxyl groups on the cellulose chain to form covalently bonded hydrophobic ester bonds (cellulose esters), thereby establishing a durable and highly effective water-resistant barrier on the fiber surface. Sizing agents are added during the papermaking process to improve the water resistance and printability of office paper.

[0003] However, recycled fibers must not be added to household paper products such as tissues, napkins, and handkerchiefs, and no sizing agents are added during the production process of household paper products.

[0004] Some companies reprocess used office paper or waste paper scraps from the office paper cutting process into pulp for use in manufacturing household paper to reduce costs. This pulp is usually used in the middle layer of household paper (tissues and napkins are generally composed of 3 or more layers of paper).

[0005] This process introduces AKD and ASA into tissue paper products. Therefore, a method is needed to identify whether tissue paper products contain recycled fibers (waste pulp).

[0006] Existing methods lack a simple, rapid, low-cost qualitative testing method applicable to multiple sizing agents simultaneously, which can effectively distinguish and qualitatively identify whether the sizing agent remaining in the paper is AKD or ASA, etc. This is an urgent problem to be solved in actual production quality control and process optimization. Summary of the Invention

[0007] This invention proposes a qualitative detection method for AKD and ASA sizing agents in paper products, which solves the deficiency of existing technologies in lacking a qualitative detection method for AKD and ASA sizing agents in paper products.

[0008] The specific technical solution of the present invention is as follows:

[0009] Qualitative testing methods for AKD and ASA sizing agents in paper products include the following steps:

[0010] (1) Sample processing

[0011] Take samples, and take samples of the same mass from different parts of the sample, cut them into small pieces and mix them for later use;

[0012] (2) Sample preparation

[0013] Weigh out several portions of the same mass of the above-mentioned shredded sample and add them into several sample pyrolysis tubes for testing;

[0014] (3) Preparation of comparison samples

[0015] A certain amount of AKD and ASA solutions were taken and placed into two different control sample pyrolysis tubes for testing.

[0016] (4) Detection by thermal pyrolysis-gas chromatography-mass spectrometry

[0017] The pyrolysis apparatus, gas chromatograph, and mass spectrometer are connected in sequence. The sample pyrolysis tube and the control sample pyrolysis tube are placed into the pyrolysis apparatus one by one for pyrolysis. Rapid heating is carried out in an inert atmosphere to generate pyrolysis products. The pyrolysis products are directly introduced into the gas chromatograph system for separation and then into the mass spectrometer for detection. The composition of the sample is determined by qualitative and quantitative analysis of the characteristic fragment ions after high-temperature pyrolysis.

[0018] The thermal pyrolysis apparatus first dries the sample thermal pyrolysis tube and the control sample thermal pyrolysis tube at 105℃ for 120s, and then thermally pyrolyzes them at 600℃ for 40s, with nitrogen or helium as the carrier gas.

[0019] The gas chromatograph uses a 5% diphenyl / 95% disiloxane column, with nitrogen or helium as the carrier gas, a flow rate of 1.2 mL / min, and a split ratio of 1:50. The initial temperature of the gas chromatograph is 45℃, held for 3 min, then increased to 300℃ at a rate of 15℃ / min, and held for 10 min.

[0020] The mass spectrometer uses an ion source temperature of 300℃, employs full scan mode, and scans a mass-to-charge ratio range of 29-650 amu; an electron impact ion source (EI) with an electron impact energy of 70 eV; a quadrupole temperature of 150℃; and a solvent delay of 1.5 min.

[0021] Furthermore, in the sample processing step, 0.5g of sample is taken from different parts of the sample, cut into pieces smaller than 1mm×1mm, and mixed for later use.

[0022] Furthermore, in the test sample preparation step, three 0.5 mg portions of the above-mentioned shredded sample were weighed and added to three sample pyrolysis tubes for testing.

[0023] Furthermore, 5 μL of AKD and ASA solutions were taken and placed into two different control sample pyrolysis tubes for testing. The mass concentration of both AKD and ASA solutions was 0.1 mg / mL.

[0024] The beneficial effects of this invention: Sizing agents such as AKD and ASA are important components in the paper production process, and are present in most papers or products using recycled papermaking fiber raw materials. Through research, a pyrolysis-gas chromatography-mass spectrometry (GC-MS) method was used to qualitatively determine AKD and ASA in paper products. The paper sample was directly placed in a pyrolysis apparatus connected to a gas chromatograph. At high temperatures, cellulose completely decomposed into volatile substances, releasing both reacted and unreacted sizing agents into a series of characteristic substances such as hydrocarbons. The presence of AKD and ASA in the paper product can be qualitatively analyzed from the GC-MS test data. This technical solution is simple, rapid, and low-cost, providing a reliable basis for paper identification and fiber origin analysis. Attached Figure Description

[0025] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art 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.

[0026] Figure 1 TIC chart for AKD;

[0027] Figure 2 A TIC diagram for ASA;

[0028] Figure 3 TIC comparison chart of AKD and sample #1;

[0029] Figure 4 This is a comparison chart of TIC values ​​for ASA and sample #2. Detailed Implementation

[0030] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0031] Qualitative testing methods for AKD and ASA sizing agents in paper products include the following steps:

[0032] (1) Sample processing

[0033] Take samples, and take samples of the same mass from different parts of the sample, cut them into small pieces and mix them for later use;

[0034] (2) Sample preparation

[0035] Weigh out several portions of the same mass of the above-mentioned shredded sample and add them into several sample pyrolysis tubes for testing;

[0036] (3) Preparation of comparison samples

[0037] A certain amount of AKD and ASA solutions were taken and placed into two different control sample pyrolysis tubes for testing.

[0038] (4) Detection by thermal pyrolysis-gas chromatography-mass spectrometry

[0039] The pyrolysis apparatus, gas chromatograph, and mass spectrometer are connected in sequence. The sample pyrolysis tube and the control sample pyrolysis tube are placed into the pyrolysis apparatus one by one for pyrolysis. Rapid heating is carried out in an inert atmosphere to generate pyrolysis products. The pyrolysis products are directly introduced into the gas chromatograph system for separation and then into the mass spectrometer for detection. The composition of the sample is determined by qualitative and quantitative analysis of the characteristic fragment ions after high-temperature pyrolysis.

[0040] The thermal pyrolysis apparatus first dries the sample thermal pyrolysis tube and the control sample thermal pyrolysis tube at 105℃ for 120s, and then thermally pyrolyzes them at 600℃ for 40s, with nitrogen or helium as the carrier gas.

[0041] The gas chromatograph uses a 5% diphenyl / 95% disiloxane column, with nitrogen or helium as the carrier gas, a flow rate of 1.2 mL / min, and a split ratio of 1:50. The initial temperature of the gas chromatograph is 45℃, held for 3 min, then increased to 300℃ at a rate of 15℃ / min, and held for 10 min.

[0042] The mass spectrometer uses an ion source temperature of 300℃, employs full scan mode, and scans a mass-to-charge ratio range of 29-650 amu; an electron impact ion source (EI) with an electron impact energy of 70 eV; a quadrupole temperature of 150℃; and a solvent delay of 1.5 min.

[0043] As a preferred embodiment, in the sample processing step, 0.5g of sample is taken from different parts of the sample, cut into pieces smaller than 1mm×1mm, and mixed for later use.

[0044] As a preferred embodiment, in the test sample preparation step, three 0.5 mg portions of the above-mentioned shredded sample are weighed and added to three sample pyrolysis tubes for testing.

[0045] As a preferred embodiment, 5 μL of AKD and ASA solutions were respectively placed into two different control sample pyrolysis tubes for testing. The mass concentration of both AKD and ASA solutions was 0.1 mg / mL.

[0046] Sizing agents such as AKD and ASA are crucial components of the paper production process, and are present in most papers and products using recycled papermaking fibers. This study employed a pyrolysis-gas chromatography-mass spectrometry (GC-MS) method for the qualitative determination of AKD and ASA in paper products. Paper samples were directly placed in a pyrolysis apparatus connected to a gas chromatograph. At high temperatures, cellulose completely decomposed into volatile substances, releasing both reacted and unreacted sizing agents into a series of characteristic hydrocarbons. The presence of AKD and ASA in the paper can be qualitatively determined from the GC-MS data. This technique is simple, rapid, and cost-effective, providing a reliable basis for paper identification and fiber origin analysis.

[0047] Experimental testing

[0048] Qualitative testing methods for AKD and ASA sizing agents in paper products include the following steps:

[0049] (1) Sample processing

[0050] Select paper products with AKD, paper products with ASA, and paper products without AKD and ASA, and name them Sample 1, Sample 2, and Sample 3, respectively. Take 0.5g of sample from different parts of Sample 1, cut it into pieces smaller than 1mm×1mm and mix them for later use. Take 0.5g of sample from different parts of Sample 2, cut it into pieces smaller than 1mm×1mm and mix them for later use. Take 0.5g of sample from different parts of Sample 3, cut it into pieces smaller than 1mm×1mm and mix them for later use.

[0051] (2) Sample preparation

[0052] Weigh 0.5 mg of the above-mentioned shredded sample 1#, sample 2# and sample 3# respectively, and add them into three sample pyrolysis tubes for testing. They are named sample pyrolysis tube 1#, sample pyrolysis tube 2# and sample pyrolysis tube 3# respectively.

[0053] (3) Preparation of comparison samples

[0054] Take 5 μL of AKD and ASA solutions respectively. The mass concentration of AKD and ASA solutions is 0.1 mg / mL. Put them into two different control sample pyrolysis tubes for testing. They are named AKD control sample pyrolysis tube and ASA control sample pyrolysis tube respectively.

[0055] (4) Detection by thermal pyrolysis-gas chromatography-mass spectrometry

[0056] The pyrolysis apparatus, gas chromatograph, and mass spectrometer were connected sequentially. The pyrolysis tubes of sample 1#, sample 2#, sample 3#, AKD comparison sample, and ASA comparison sample were placed one by one into the pyrolysis apparatus for pyrolysis. Rapid heating was performed in an inert atmosphere to generate pyrolysis products. The pyrolysis products were directly introduced into the gas chromatograph system for separation and then into the mass spectrometer for detection. The composition of the sample was determined by qualitative and quantitative analysis of the characteristic fragment ions after high-temperature pyrolysis.

[0057] The thermal pyrolysis apparatus first dries the sample thermal pyrolysis tube and the control sample thermal pyrolysis tube at 105℃ for 120s, and then thermally pyrolyzes them at 600℃ for 40s, with nitrogen or helium as the carrier gas.

[0058] The gas chromatograph used a 5% diphenyl / 95% disiloxane column (TG-5MS, 30m×0.25mm×0.25μm), with nitrogen or helium as the carrier gas, a flow rate of 1.2mL / min, and a split ratio of 1:50. The initial temperature of the gas chromatograph was 45℃, held for 3 min, then increased to 300℃ at a rate of 15℃ / min, and held for 10 min.

[0059] The mass spectrometer uses an ion source temperature of 300℃, employs full scan mode, and has a scan mass-to-charge ratio (m / z) range of 29-650 amu; an electron impact ion source (EI) with an electron impact energy of 70 eV; a quadrupole temperature of 150℃; and a solvent delay of 1.5 min.

[0060] For details of the TIC graph measured by AKD, please refer to [link / reference]. Figure 1 In this diagram, the red boxes mark the characteristic analytes. The TIC (Total Ion Chromatogram) is a two-dimensional chromatogram used in chromatography-mass spectrometry (GC-MS) to record the change in the total intensity of all ions over time, and is used to analyze the separation and detection of sample components. For details on the TIC chromatogram measured by ASA, please refer to [link to ASA diagram]. Figure 2 The red boxes mark the characteristic features. For a comparison of AKD and TIC of sample #1, please see... Figure 3 The blue line in the figure represents the chromatogram of AKD standard, and the black line represents the test chromatogram of sample #1, indicating the presence of AKD. For a comparison of the TIC values ​​of ASA and sample #2, please see [link to TIC chart]. Figure 4 The red line in the figure is the chromatogram of ASA standard, and the black line is the test chromatogram of sample #2. The test result shows that it contains ASA.

[0061] The table below shows the characteristic compounds and qualitative ions of AKD and ASA sizing agents:

[0062]

[0063] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A qualitative detection method for AKD and ASA sizing agents in paper products, characterized in that: Includes the following steps: (1) Sample processing Take samples, and take samples of the same mass from different parts of the sample, cut them into small pieces and mix them for later use; (2) Sample preparation Weigh out several portions of the same mass of the above-mentioned shredded sample and add them into several sample pyrolysis tubes for testing; (3) Preparation of comparison samples A certain amount of AKD and ASA solutions were taken and placed into two different control sample pyrolysis tubes for testing. (4) Detection by thermal pyrolysis-gas chromatography-mass spectrometry The pyrolysis apparatus, gas chromatograph, and mass spectrometer are connected in sequence. The sample pyrolysis tube and the control sample pyrolysis tube are placed into the pyrolysis apparatus one by one for pyrolysis. Rapid heating is carried out in an inert atmosphere to generate pyrolysis products. The pyrolysis products are directly introduced into the gas chromatograph system for separation and then into the mass spectrometer for detection. The composition of the sample is determined by qualitative and quantitative analysis of the characteristic fragment ions after high-temperature pyrolysis. The thermal pyrolysis apparatus first dries the sample thermal pyrolysis tube and the control sample thermal pyrolysis tube at 105℃ for 120s, and then thermally pyrolyzes them at 600℃ for 40s, with nitrogen or helium as the carrier gas. The gas chromatograph uses a 5% diphenyl / 95% disiloxane column, with nitrogen or helium as the carrier gas, a flow rate of 1.2 mL / min, and a split ratio of 1:

50. The initial temperature of the gas chromatograph is 45℃, held for 3 min, then increased to 300℃ at a rate of 15℃ / min, and held for 10 min. The mass spectrometer uses an ion source temperature of 300℃, employs full scan mode, and scans a mass-to-charge ratio range of 29-650 amu; an electron impact ion source (EI) with an electron impact energy of 70 eV; a quadrupole temperature of 150℃; and a solvent delay of 1.5 min.

2. The qualitative detection method for AKD and ASA sizing agents in paper products as described in claim 1, characterized in that: In the sample processing steps, 0.5g of sample is taken from different parts of the sample, cut into pieces smaller than 1mm×1mm and mixed for later use.

3. The qualitative detection method for AKD and ASA sizing agents in paper products as described in claim 1, characterized in that: In the sample preparation step, three 0.5 mg portions of the above-mentioned shredded sample were weighed and added to three sample pyrolysis tubes for testing.

4. The qualitative detection method for AKD and ASA sizing agents in paper products as described in claim 1, characterized in that: Take 5 μL of AKD and ASA solutions respectively and put them into two different control sample pyrolysis tubes for testing. The mass concentration of AKD and ASA solutions is 0.1 mg / mL.

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