Method for rapid quantitative detection of metal film oil stain residual amount

Abstract

The application discloses a method for rapidly and quantitatively detecting the residual amount of oil stains on a metal film, which comprises the following steps: adjusting the carrier gas flow rate and the test temperature of a total organic carbon analyzer; preparing a plurality of total carbon standard solutions with different concentrations; using the total organic carbon analyzer to establish a total carbon standard curve with the total carbon concentration as the horizontal coordinate and the response value of a non-dispersive infrared detector as the vertical coordinate; inputting the obtained total carbon standard curve into a solid sample input unit; cutting the metal film to a set size to prepare a metal film sample; placing the metal film sample in a treated sample boat using treated tweezers; placing the sample boat in the solid sample input unit for combustion catalytic oxidation; taking the input total carbon standard curve as a standard line to measure the TC concentration value in the combustion gas; and dividing the TC concentration value by the area of the metal film sample to obtain the residual amount of oil stains on the metal film sample.

Description

Technical Field

[0001] The invention belongs to the field of analytical chemistry, and in particular relates to a method for rapid quantitative detection of oil residue. Background Art

[0002] Residual oil is primarily composed of low-content organic matter, with minimal inorganic carbon. Residual oil on metal film surfaces can severely impact the quality of related products, making surface oil-free a crucial quality control criterion. The rolling process of metal films introduces rolling oil, machine oil, and other contaminants. To ensure product quality, residual oil analysis is essential.

[0003] Because the amount of oil residue is minimal and difficult to clean, analysis after cleaning is not feasible. Currently, gravimetric or extraction methods are used. However, gravimetric methods have poor sensitivity and require extremely high weighing accuracy. Extraction methods, on the other hand, have the disadvantages of cumbersome steps and long analysis cycles.

[0004] Since there is very little inorganic carbon on the surface of the metal film and the organic carbon is mainly oil, the total organic carbon analyzer (TOC) combined with the solid sampling unit can directly measure the total carbon content on the metal film surface. In the process of evaluating the amount of residual oil, it has the characteristics of fast analysis, high sensitivity, and green environmental protection. It is very suitable for the analysis of the amount of residual oil on the metal film surface. The TC content obtained after the measurement directly reflects the amount of residual oil on the metal film surface.

[0005] Total organic carbon analyzer refers to an instrument for measuring total organic carbon (TOC) in a solution. Its measurement principle is that organic carbon in the solution is converted into carbon dioxide by oxidation, and the carbon dioxide content is measured by a detector after interference substances are eliminated. The total organic carbon in the solution is quantitatively determined by using the corresponding relationship between the carbon content of carbon dioxide and the total organic carbon. There are mainly three types of measurement methods of the total organic carbon analyzer. Wet oxidation-non-dispersive infrared detection, which is to remove inorganic carbon in the sample by phosphoric acid treatment before the sample is oxidized by acidic potassium persulfate, and then measure the concentration of TOC. However, wet oxidation is not sufficient for the oxidation of water bodies containing high-molecular-mass compounds such as humic acid. Ultraviolet-wet oxidation-non-dispersive infrared detection, which is the synergistic effect of ultraviolet oxidation and wet oxidation, and is suitable for measuring heavily polluted water bodies because the ultraviolet oxidation method cannot be used for complex water bodies with high TOC content. High-temperature catalytic combustion oxidation-non-dispersive infrared detection, in which the organic carbon in the sample is converted into carbon dioxide under high-temperature catalytic oxidation conditions, and then detected by non-dispersive infrared (NDIR), because the high-temperature combustion is relatively complete, it is suitable for heavily polluted water bodies or complex water bodies, but the influence of high salt content of the sample on the measurement results needs to be considered. In addition, the ultraviolet oxidation-non-dispersive infrared detection, resistance method, ultraviolet absorption spectrum, and conductance method are not suitable for the field of soil science because of poor stability or incomplete oxidation of particulate and high-molecular-mass organic matter. When the soil and sediment samples are treated into solution samples, the treatment of floating or sinkable solid substances with a certain particle size needs to be considered. SUMMARY

[0006] In view of the above problems in the prior art, the purpose of the present application is to provide a method for rapidly and quantitatively detecting the residual amount of metal film oil stain, which combines a total organic carbon analyzer (TOC) with a solid sample injection unit, greatly simplifies the pretreatment process, shortens the sample processing time and analysis time, reduces the errors caused by human operation, and improves the accuracy and reliability of the measurement results.

[0007] In order to solve the above technical problems, the technical scheme adopted by the present application is as follows: (1) sample cutting preparation; (2) cleaning and high-temperature calcination of the sample boat and tweezers to remove any attached carbon; (3) adjusting the test conditions of the total organic carbon analyzer (TOC) and the solid sample injection unit, such as temperature, carrier gas flow, etc., and preheating and stabilizing the instrument; (4) preparing a total carbon (TC) standard solution, taking the TC concentration as the abscissa and the NDIR (non-dispersive infrared) response value as the ordinate, and directly injecting to draw a TC calibration curve; (5) measuring the TC concentration of the sample.

[0008] In order to achieve the above-mentioned purpose, the present invention provides a method for rapid quantitative detection of oil residue on metal film, which comprises the following steps: (1) adjusting the carrier gas flow rate and test temperature of the total organic carbon analyzer; (2) preparing a plurality of total carbon standard solutions of different concentrations, using the total organic carbon analyzer of step (1), with the total carbon concentration as the horizontal coordinate and the response value of the non-dispersive infrared detector as the vertical coordinate, to establish a total carbon standard curve; (3) inputting the total carbon standard curve obtained in step (2) into the solid sampling unit, and adjusting the carrier gas flow rate and test temperature of the solid sampling unit; (4) Clean and high-temperature calcine the sample boat and tweezers to remove the carbon elements attached to the sample boat and tweezers; (5) cut the metal film to a set size to prepare a metal film sample; and (6) use the tweezers treated in step (4) to place the metal film sample of step (5) into the sample boat treated in step (4), and then place the sample boat in a solid sampling unit for combustion catalytic oxidation. Using the input total carbon standard curve as the standard line, measure the TC concentration value in the combustion gas, divide the TC concentration value by the area of ​​the metal film sample, and obtain the metal film oil residue of the metal film sample.

[0009] Alternatively, the total organic carbon analyzer used in the present invention may be a TOC-L series TOC analyzer sold by Guangdong Jingpu Industrial Co., Ltd., which has a measurement range of 4 μg / L to 30,000 μg / L.

[0010] Alternatively, the solid sample injection unit used in the present invention may be the solid sample measurement unit SSM-5000A sold by Guangdong Jingpu Industrial Co., Ltd.

[0011] According to the above scheme, in step (1), the carrier gas used by the total organic carbon analyzer is oxygen with a purity greater than 99.99%, and the carrier gas flow rate is set to 20 mL / min.

[0012] According to the above scheme, the standard substance used in step (2) is glucose, sucrose or benzene series, which is converted into total carbon concentration and injected in a gradient manner.

[0013] According to the above scheme, in step (3), the carrier gas used in the solid sample introduction unit is oxygen with a purity greater than 99.99%, and the carrier gas flow rate is set to 500 mL / min.

[0014] According to the above scheme, the sample boat in step (4) is a high-temperature resistant alumina ceramic boat.

[0015] According to the above scheme, the tweezers in step (4) are high-temperature resistant metal tweezers.

[0016] According to the above scheme, in step (4), the steps of cleaning the sample boat and the tweezers are: (4-1) soaking the sample boat and the tweezers in 2 mol / L sulfuric acid or hydrochloric acid for 5-15 minutes; and (4-2) cleaning the sample boat and the tweezers 2-3 times with deionized water.

[0017] According to the above scheme, in step (4), the high-temperature calcination of the sample boat is set as: emptying the sample boat at 850-950 degrees Celsius for at least 20 minutes.

[0018] According to the above scheme, in step (4), the high-temperature calcination of the tweezers is set as: using an electric stove or a gas lamp to burn the tip of the tweezers to red.

[0019] According to the above scheme, in step (6), the furnace temperature of the solid sample introduction unit is set to 850-950 degrees Celsius.

[0020] The present application has the following advantages: (1) The present application does not require water washing, weighing, or organic solvent extraction of the oil stains on the surface of the metal film, but only needs to cut and fold the metal film and place it in the sample boat for analysis under the set conditions, which has the characteristics of high accuracy, fast analysis speed, high sensitivity, and green environmental protection; (2) The method of the present application has universal applicability and is easy to use. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 The steps of the method for rapidly and quantitatively detecting the amount of oil stains on a metal film of the present application are shown.

[0022] Figure 2 The total carbon standard curve of Example 1 of the present application is shown. DETAILED DESCRIPTION

[0023] The embodiments of the present application will be described in detail below, and examples of the embodiments are shown in the accompanying drawings, in which the same or similar reference numerals represent the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by reference to the accompanying drawings are exemplary and are intended to explain the present application, and cannot be understood as limiting the present application.

[0024] As a non-limiting embodiment, the method for rapidly and quantitatively detecting the amount of oil stains on a metal film of the present application is as follows: Figure 1As shown, first in step S1, the carrier gas flow rate and test temperature of the total organic carbon analyzer are debugged. Then, in step S2, several total carbon standard solutions of different concentrations are prepared, and the total organic carbon analyzer of step S1 is used to establish a total carbon standard curve with the total carbon concentration as the horizontal coordinate and the response value of the non-dispersive infrared detector as the vertical coordinate. Subsequently, in step S3, the total carbon standard curve obtained in step S2 is input into the solid sampling unit, and the carrier gas flow rate and test temperature of the solid sampling unit are debugged. Then, in step S4, the sample boat and tweezers are cleaned and calcined at high temperature to remove the carbon elements attached to the sample boat and tweezers. In step S5, the metal film is cut to a set size to prepare a metal film sample. Finally, in step S6, the metal film sample of step S5 is placed in the sample boat processed in step S4 using the tweezers processed in step S4, and the sample boat is placed in a solid sampling unit for combustion catalytic oxidation. The TC concentration value in the combustion gas is measured using the input total carbon standard curve as the standard line, and the TC concentration value is divided by the area of ​​the metal film sample to obtain the metal film oil residue of the metal film sample.

[0025] In this non-limiting embodiment, in step S1 and step S3, the carrier gas used by the total organic carbon analyzer and the solid sampling unit is oxygen with a purity greater than 99.99%, the carrier gas flow rate is set to 20 mL / min, and the carrier gas flow rate of the solid sampling unit is set to 500 mL / min.

[0026] The standard substance used in step S2 is glucose, sucrose or benzene series, which is converted into total carbon concentration and gradient injection is performed to obtain a total carbon standard curve.

[0027] In order to ensure the accuracy of the experimental data, the sample boat in step (4) is a high-temperature resistant alumina ceramic boat, and the tweezers are high-temperature resistant metal tweezers, so as to prevent interference factors between the sample boat and the tweezers during the high-temperature combustion and oxidation process.

[0028] In one non-limiting embodiment, in step S4, the steps of cleaning the sample boat and tweezers are: (4-1) soaking the sample boat and tweezers in 2 mol / L sulfuric acid or hydrochloric acid for 5-15 minutes; and (4-2) rinsing the sample boat and tweezers 2-3 times with deionized water. The high-temperature calcination of the sample boat is performed by calcining the sample boat at 850°C to 950°C for at least 20 minutes. The high-temperature calcination of the tweezers is performed by using an electric furnace or gas lamp to burn the tips of the tweezers until they turn red.

[0029] The following uses Example 1 as an example to illustrate a method for rapidly and quantitatively detecting the amount of oil residue on a metal film.

[0030] Example 1

[0031] First, debug the test conditions of the total organic carbon analyzer (TOC), use the reference substance sucrose as the standard solution for TC determination, and the carbon concentration is 100 mg / L. Inject 0, 50, 100, and 200 μL respectively, and draw the TC calibration curve with TC concentration as the horizontal axis and NDIR response value as the vertical axis, as shown in the figure. Figure 2 shown.

[0032] The TC calibration curve was then input into the solid sample introduction unit. The test conditions of the solid sample introduction unit were adjusted, and the furnace temperature was raised to 900°C to allow the instrument to warm up and stabilize. The sample boat and tweezers were cleaned and then calcined at high temperature.

[0033] Finally, four metal film samples were taken, each cut into 2 to 3 pieces of known area, placed in a sample boat, and directly injected through a solid sampling unit to measure the TC content. The results are shown in Table 1.

[0034] Table 1. Metal film measurement results

[0035]

[0036] Throughout this specification, reference to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples" means that a specific feature, structure, or characteristic described in conjunction with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, those skilled in the art may combine and integrate different embodiments or examples, as well as features of different embodiments or examples, described in this specification, unless they conflict with each other.

[0037] Although the embodiments of the present invention have been shown and described above, it will be understood that the above embodiments are illustrative and are not to be construed as limitations on the present invention. A person skilled in the art may change, modify, replace and modify the above embodiments within the scope of the present invention.

Claims

1. A method for rapid quantitative detection of oil residue on metal film, characterized in that: The following steps are involved: (1) Debug the carrier gas flow rate and test temperature of the total organic carbon analyzer; (2) preparing several total carbon standard solutions of different concentrations, and using the total organic carbon analyzer of step (1), establishing a total carbon standard curve with the total carbon concentration as the abscissa and the response value of the non-dispersive infrared detector as the ordinate; (3) Inputting the total carbon standard curve obtained in step (2) into the solid sampling unit, and adjusting the carrier gas flow rate and test temperature of the solid sampling unit; (4) Cleaning and high-temperature burning the sample boat and tweezers to remove the carbon elements attached to the sample boat and the tweezers; (5) Cutting the metal film to a set size to prepare a metal film sample; as well as (6) using the tweezers treated in step (4) to place the metal film sample of step (5) into the sample boat treated in step (4), and then placing the sample boat in the solid sampling unit for combustion catalytic oxidation, using the input total carbon standard curve as the standard line, measuring the TC concentration value in the combustion gas, and dividing the TC concentration value by the area of ​​the metal film sample to obtain the metal film oil residue of the metal film sample; in, In step (1), the carrier gas used in the total organic carbon analyzer is oxygen with a purity greater than 99.99%, and the carrier gas flow rate is set to 20 mL / min; In step (2), the standard solution used to establish the total carbon standard curve has a carbon concentration of 100 mg / L, and 0, 50, 100, and 200 μL are injected respectively; In step (3), the carrier gas used in the solid sample introduction unit is oxygen with a purity greater than 99.99%, and the carrier gas flow rate is set to 500 mL / min; In step (4), the steps of cleaning the sample boat and the tweezers are: (4-1) Soaking the sample boat and the tweezers in 2 mol / L sulfuric acid or hydrochloric acid for 5 to 15 minutes; and (4-2) washing the sample boat and the tweezers 2 to 3 times with deionized water; and The high temperature burning of the sample boat is set as follows: burning the sample boat empty at 850 degrees Celsius to 950 degrees Celsius for at least 20 minutes; In step (6), the furnace temperature of the solid sample introduction unit is set to 850°C to 950°C.

2. The method for rapid quantitative detection of oil residue on metal film according to claim 1, characterized in that: In step (2), the standard substance used to prepare the total carbon standard solution is set to glucose, sucrose or benzene series.

3. The method for rapid quantitative detection of oil residue on metal film according to claim 1, characterized in that: The sample boat in step (4) is a high-temperature resistant alumina ceramic boat.

4. The method for rapid quantitative detection of oil residue on metal film according to claim 3, characterized in that: The tweezers in step (4) are high-temperature resistant metal tweezers.

5. The method for rapid quantitative detection of oil residue on metal film according to claim 4, characterized in that: In step (4), the high temperature burning of the tweezers is set to use an electric stove or a gas lamp to burn the tip of the tweezers until it turns red.

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