Method for analyzing natural degree in fuel oil by using liquid flash three-tube conforming internal standard method and application

Abstract

The invention provides a method for analyzing the naturalness of fuel oil by using a liquid flash three-tube conforming internal standard method and application thereof. The method comprises the following steps: firstly, measuring a sample to be measured by using a liquid flash counter to obtain a three-tube count of the sample to be measured; adding the 14C standard substance into the to-be-detected sample to obtain a labeled sample, and calculating the counting efficiency of the labeled sample according to the three-tube count of the to-be-detected sample, the three-tube coincidence count of the labeled sample and the three-tube coincidence count of the background sample; and calculating the natural degree content of the biofuel according to the counting efficiency of the labeled sample and the carbon content of the biofuel. According to the method, the efficiency change in the measurement process is corrected by adding the internal standard substance with the known activity into the sample, so that the measurement accuracy and reliability are improved, the chemiluminescence and photoluminescence of the sample can be shielded by combining a three-tube coincidence technology, the analysis time is shortened, and the measurement accuracy of the low-activity sample is improved.

Description

Technical Field

[0001] The present application relates to the technical field of biofuel naturalness detection, and in particular to a method and application for analyzing the naturalness of fuel using a liquid scintillation triple tube internal standard method. Background Art

[0002] Driven by the global "dual carbon" goal, countries are actively adjusting their energy structures, with a particular focus on developing biofuels to replace traditional fossil fuels. Biofuels are favored for their sustainability and because they do not increase the total amount of carbon in the atmosphere. They not only help mitigate climate change, but also promote the diversification of the energy industry and enhance the security and stability of energy supply. In order to ensure the effective regulation of biofuels, it is necessary to accurately measure the bio-based content in fuel. 14 The radioactivity measurement technique of C is widely used due to its effectiveness in distinguishing between bio-based and fossil fuels.

[0003] 14 As a pure β radionuclide, C is usually measured by a liquid scintillation counter (LSC). In LSC measurement, traditional sample preparation methods use methods such as benzene synthesis and carbon dioxide absorption, both of which may introduce more errors due to chemical treatment or incomplete combustion. In order to simplify the process and improve the accuracy of the measurement, the direct LSC method was proposed, which directly mixes the biofuel sample with scintillation liquid for measurement. In liquid scintillation measurement, the reaction of chemical substances will produce interfering light signals, and due to the natural sample 14 The C content is extremely low, so the real signal of the sample is weak, and the interference by chemiluminescence will be more serious. Usually, the interference is reduced by placing it away from light for a long time and waiting for the chemical reaction to end. The light-proof storage time is very long, usually more than 24 hours. In a three-tube two-tube coincidence liquid scintillation counter, three photomultiplier tubes can be added together to eliminate the interference of chemiluminescence. The present invention will use three photomultiplier tubes to count, which overcomes the traditional method that requires long-term sample placement due to shielding chemiluminescence, resulting in long measurement time. Summary of the invention

[0004] In view of this, the present application provides a method and application for analyzing the naturalness of fuel using a liquid scintillation triple tube in accordance with the internal standard method, which solves the technical problem in the prior art that the traditional LSC is used to measure the naturalness of fuel in order to reduce the interference light signal generated by the reaction of chemical substances, thus requiring long-term light-proof storage, resulting in a long measurement time.

[0005] In the first aspect of the present application, the present application provides a method for analyzing the natural content of fuel using a liquid scintillation three-tube internal standard method, the analysis method comprising: adding biofuel and scintillation liquid to a sample bottle to be tested and mixing them evenly to obtain a sample to be tested, using a liquid scintillation counter to measure the sample to be tested to obtain a three-tube count of the sample to be tested; adding14 C standard substance is used to obtain a spiked sample, and a liquid scintillation counter is used to measure the three-tube coincidence count of the spiked sample; mineral oil and scintillation liquid are added to a background sample bottle and mixed evenly to obtain a background sample, and a liquid scintillation counter is used to perform a first measurement of the three-tube coincidence count of the background sample and a second measurement of the three-tube coincidence count of the background sample; the counting efficiency of the spiked sample is calculated according to the measured three-tube coincidence count of the spiked sample and the three-tube coincidence count of the background sample; the carbon content of the biofuel is measured using an element analyzer, and the natural content of the biofuel is calculated according to the counting efficiency of the spiked sample and the carbon content of the biofuel.

[0006] In one embodiment, the calculating the counting efficiency of the spiked sample according to the measured three-tube coincidence count of the spiked sample and the three-tube coincidence count of the background sample comprises: calculating the counting efficiency of the spiked sample according to formula (1);

[0007] ε=(T S / t s -T FFB / t s ) / A formula (1)

[0008] In formula (1):

[0009] ε is the counting efficiency;

[0010] T S The three tubes of spiked samples are counted in compliance;

[0011] t s is the measurement time of the spiked sample;

[0012] T FFB The three tubes of the background sample for the second measurement are counted in accordance with the standard;

[0013] A is 14 C is the activity of the standard substance.

[0014] In one embodiment, the natural content of the biofuel is calculated based on the three-tube coincidence count of the sample to be tested, the three-tube coincidence count of the background sample measured for the second time, the counting efficiency of the spiked sample, and the carbon content of the biofuel, including: calculating the natural content of the biofuel according to formula (2);

[0015]

[0016] In formula (2):

[0017] N is the natural content of biofuel;

[0018] T BF The three tubes of the sample to be tested are counted;

[0019] TFF The three tubes of the background sample measured for the first time are counted in coincidence;

[0020] ε is the counting efficiency of the spiked sample;

[0021] t BF is the measurement time of the sample to be tested;

[0022] m represents the mass of biofuel;

[0023] ω represents the carbon content of biofuel.

[0024] In one embodiment, the time for measuring the sample using a liquid scintillation counter is 0.1-240 hours.

[0025] In one embodiment, the time for measuring the spiked sample using a liquid scintillation counter is 0.03-120 hours.

[0026] In one embodiment, the time for measuring the background sample for the first time using the liquid scintillation counter is 0.1-240 hours; the time for measuring the background sample for the second time using the liquid scintillation counter is 0.03-120 hours.

[0027] In one embodiment, the volume ratio of the fuel sample to the scintillation fluid is 1:(1-2).

[0028] In one embodiment, the volume ratio of the mineral oil and the scintillation fluid is 1:(1-2).

[0029] In one embodiment, the 14 The activity of C standard substances is 1-10000 Bq / mL.

[0030] In a second aspect of the present application, the present application provides an application of the above-mentioned method for analyzing the naturalness of fuel in analyzing the naturalness content in biofuel.

[0031] The present application provides a method and application thereof for analyzing the natural content of fuel oil by using a liquid scintillation three-tube internal standard method. The analysis method comprises: adding biofuel and scintillation liquid to a sample bottle to be tested and mixing them evenly to obtain a sample to be tested; using a liquid scintillation counter to measure the sample to be tested and obtain a three-tube count of the sample to be tested; adding 14C standard substance is used to obtain spiked samples, and a liquid scintillation counter is used to measure the three-tube coincidence count of the spiked samples; mineral oil and scintillation liquid are added to the background sample bottle and mixed evenly to obtain the background sample, and a liquid scintillation counter is used to measure the three-tube coincidence count of the background sample for the first measurement and the three-tube coincidence count of the background sample for the second measurement; the counting efficiency of the spiked sample is calculated according to the three-tube coincidence count of the spiked sample and the three-tube coincidence count of the background sample; the carbon content of the biofuel is measured using an elemental analyzer, and the natural content of the biofuel is calculated according to the counting efficiency of the spiked sample and the carbon content of the biofuel. The efficiency change during the measurement process is corrected by adding an internal standard of known activity to the sample, thereby improving the accuracy and reliability of the measurement. Combined with the three-tube coincidence technology, the chemiluminescence and photoluminescence of the sample can be shielded to a large extent, shortening the analysis time and increasing the accuracy of the measurement of low-activity samples. Therefore, the three-tube coincidence internal standard method is more sensitive and accurate in measuring the natural content in fuel. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 The example 1 of the present application is shown as follows 14 C Peak area graph of three tubes in accordance with the count values;

[0033] Figure 2 The example 2 of this application is shown. 14 C Peak area graph of three tubes that match the count values;

[0034] Figure 3 The example 3 of the present application provides 14 C Peak area graph of three tubes in accordance with the count values;

[0035] Figure 4 The example 4 of the present application is shown. 14 C Peak area graph of the three tubes that match the count values. DETAILED DESCRIPTION

[0036] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the specific embodiments of the present invention and the corresponding drawings. In the description of the present invention, it should be noted that the term "or" is usually used in the sense of including "and / or", unless the content clearly indicates otherwise.

[0037] Example 1

[0038] Add 10 ml of biofuel sample and 10 ml of scintillation liquid into a 20 ml low potassium glass liquid scintillation bottle, mix the biofuel sample and scintillation liquid evenly to prepare the sample to be tested; use a liquid scintillation counter to measure the three-tube count (T BF ), the measurement time is 4 hours, and the three-tube count T of the sample to be tested is obtained.BF ; Add 0.1mL of 1100Bq / mL of 14 C standard substance to obtain spiked samples, and a liquid scintillation counter was used to measure the coincidence counts (T S ), the measurement time is 20 minutes.

[0039] Take another 20mL low potassium glass scintillation bottle, add 10mL of mineral oil No. 10 and 10mL of scintillation liquid to the low potassium glass scintillation bottle. Mix well and use it as the background sample. Use a liquid scintillation counter to measure the three tube coincidence counts of the background sample for the first time (T FF ), the measurement time is 4 hours, and then a liquid scintillation counter is used to measure the background sample for the second time. The three tube coincidence count (T FFB ), the measurement time is 20 minutes.

[0040] After measurement, the three-tube count value of the sample to be tested is 31271, the three-tube count value of the background sample measured for the first time is 6744, the three-tube count value of the spiked sample is 120366, and the three-tube count value of the background sample measured for the second time is 562. Figure 1 The example 1 of the present application is shown as follows 14 C Peak area graph of the three tubes that meet the count value; The three tubes of spiked samples that meet the count value are Figure 1 Integration of the peak area.

[0041] The second measurement of the three tubes of the background sample coincides with the count (T FFB ) is for and join 14 The measurement time of the C standard substance and the spiked sample is consistent, and the three tubes of the background sample measured for the second time are counted according to the count (T FFB ) and the three-tube coincidence count of the spiked sample (T S ), the counting efficiency of the spiked sample was calculated by formula (1), and the counting efficiency was 90.8%;

[0042] ε=(T S / t s -T FFB / t s ) / A formula (1)

[0043] In formula (1):

[0044] ε is the counting efficiency;

[0045] T S The three tubes of spiked samples are counted in compliance;

[0046] t s is the measurement time of the spiked sample;

[0047] TFFB The three tubes of the background sample for the second measurement are counted in accordance with the standard;

[0048] A is 14 C is the activity of the standard substance.

[0049] The carbon content of the biofuel was measured using an elemental analyzer (Various MACRO cube) and was found to be 85.1%.

[0050] Combining the calculated counting efficiency (ε) of the spiked sample and the carbon content (ω) of the biofuel, the natural content of the biofuel is calculated according to formula (2):

[0051]

[0052] In formula (2):

[0053] N is the natural content of biofuel;

[0054] T BF The three tubes of the sample to be tested are counted;

[0055] T FF The three tubes of the background sample measured for the first time are counted in coincidence;

[0056] ε is the counting efficiency of the spiked sample;

[0057] t BF is the measurement time of the sample to be tested;

[0058] m represents the mass of biofuel;

[0059] ω represents the carbon content of biofuel.

[0060] The natural content of the biofuel sample was calculated to be 99.5%.

[0061] Example 2

[0062] Add 10 ml of biofuel sample and 10 ml of scintillation liquid into a 20 ml low potassium glass liquid scintillation bottle, mix the biofuel sample and scintillation liquid evenly to prepare the sample to be tested; use a liquid scintillation counter to measure the three-tube count (T BF ), the measurement time is 4 hours, and the three-tube count T of the sample to be tested is obtained. BF ; Add 0.1mL of 1100Bq / mL of 14 C standard substance to obtain spiked samples, and a liquid scintillation counter was used to measure the coincidence counts (T S ), the measurement time is 20 minutes.

[0063] Take another 20mL low potassium glass scintillation bottle, add 12mL mineral oil and 6mL scintillation liquid to the low potassium glass scintillation bottle. Mix well and use it as the background sample. Use a liquid scintillation counter to measure the three tube coincidence counts of the background sample for the first time (T FF ), the measurement time is 4 hours, and then a liquid scintillation counter is used to measure the background sample for the second time. The three tube coincidence count (T FFB ), the measurement time is 20 minutes.

[0064] After measurement, the three-tube counting value of the sample to be tested was 33541, the three-tube counting value of the background sample measured for the first time was 6744, the three-tube counting value of the spiked sample was 111219, and the three-tube counting value of the background sample measured for the second time was 554. Figure 2 The example 2 of this application is shown. 14 C Peak area graph of the three tubes that meet the count value; The three tubes of spiked samples that meet the count value are Figure 2 Integration of the peak area.

[0065] The second measurement of the three tubes of the background sample coincides with the count (T FFB ) is for and join 14 The measurement time of the C standard substance and the spiked sample is consistent, and the three tubes of the background sample measured for the second time are counted according to the count (T FFB ) and the three-tube coincidence count of the spiked sample (T S ), the counting efficiency of the spiked sample was calculated by formula (1), and the counting efficiency was 83.9%;

[0066] ε=(T S / t s -T FFB / t s ) / A formula (1)

[0067] In formula (1):

[0068] ε is the counting efficiency;

[0069] T S The three tubes of spiked samples are counted in compliance;

[0070] t s is the measurement time of the spiked sample;

[0071] T FFB The three tubes of the background sample for the second measurement are counted in accordance with the standard;

[0072] A is 14 C is the activity of the standard substance.

[0073] The carbon content of the biofuel was measured using an elemental analyzer (Various MACRO cube) and was found to be 85.1%.

[0074] Combining the calculated counting efficiency (ε) of the spiked sample and the carbon content (ω) of the biofuel, the natural content of the biofuel is calculated according to formula (2):

[0075]

[0076] In formula (2):

[0077] N is the natural content of biofuel;

[0078] T BF The three tubes of the sample to be tested are counted;

[0079] T FF The three tubes of the background sample measured for the first time are counted in coincidence;

[0080] ε is the counting efficiency of the spiked sample;

[0081] t BF is the measurement time of the sample to be tested;

[0082] m Indicates the quality of biofuel;

[0083] ω represents the carbon content of biofuel.

[0084] The natural content of the biofuel sample was calculated to be 99.8%.

[0085] Example 3

[0086] Add 10 ml of biofuel sample and 10 ml of scintillation liquid into a 20 ml low potassium glass liquid scintillation bottle, mix the biofuel sample and scintillation liquid evenly to prepare the test sample for later use; use a liquid scintillation counter to measure the three-tube count of the test sample for 4 hours to obtain the three-tube count T of the test sample. BF ; Add 0.1mL of 200Bq / mL of 14 C standard substance was used to obtain spiked samples, and the coincidence counts of three tubes of the spiked samples were measured using a liquid scintillation counter for 20 minutes.

[0087] Take another 20mL low potassium glass scintillation bottle, add 12mL mineral oil and 6mL scintillation liquid to the low potassium glass scintillation bottle. Mix well and use it as the background sample. Use a liquid scintillation counter to measure the three tube coincidence counts of the background sample for the first time (T FF ), the measurement time is 4 hours, and then a liquid scintillation counter is used to measure the background sample for the second time. The three tube coincidence count (TFFB ), the measurement time is 20 minutes.

[0088] After measurement, the three-tube counting value of the sample to be tested was 33708, the three-tube counting value of the background sample measured for the first time was 6847, the three-tube counting value of the spiked sample was 202319, and the three-tube counting value of the background sample measured for the second time was 559. Figure 3 The example 3 of the present application provides 14 C Peak area graph of the three tubes that meet the count value; The three tubes of spiked samples that meet the count value are Figure 3 Integration of the peak area.

[0089] The second measurement of the three tubes of the background sample coincides with the count (T FFB ) is for and join 14 The measurement time of the C standard substance and the spiked sample is consistent, and the three tubes of the background sample measured for the second time are counted according to the count (T FFB ) and the three-tube coincidence count of the spiked sample (T S ), the counting efficiency of the spiked sample was calculated by formula (1), and the counting efficiency was 84.1%;

[0090] ε=(T S / t s -T FFB / t s ) / A formula (1)

[0091] In formula (1):

[0092] ε is the counting efficiency;

[0093] T S The three tubes of spiked samples are counted in compliance;

[0094] t s is the measurement time of the spiked sample;

[0095] T BF The three tubes of the sample to be tested are counted;

[0096] t BF is the measurement time of the sample to be tested;

[0097] A is 14 C is the activity of the standard substance.

[0098] The carbon content of the biofuel was measured using an elemental analyzer (Various MACRO cube) and was found to be 85.1%.

[0099] Combining the calculated counting efficiency (ε) and the carbon content of the sample (ω), the natural content of the biofuel is calculated according to formula (2):

[0100]

[0101] In formula (2):

[0102] N is the natural content of biofuel;

[0103] T BF The three tubes of the sample to be tested are counted;

[0104] T FF The three tubes for background samples are consistent with the count;

[0105] ε is the counting efficiency of the spiked sample;

[0106] t BF is the measurement time of the sample to be tested;

[0107] m represents the mass of biofuel;

[0108] ω represents the carbon content of biofuel.

[0109] The natural content of the biofuel sample was calculated to be 99.3%.

[0110] Example 4

[0111] Add 10 ml of biofuel sample and 10 ml of scintillation liquid into a 20 ml low potassium glass liquid scintillation bottle, mix the biofuel sample and scintillation liquid evenly to prepare the test sample for later use; use a liquid scintillation counter to measure the three-tube count of the test sample for 4 hours to obtain the three-tube count T of the test sample. BF ; Add 0.1mL of 5000Bq / mL of 14 C standard substance was used to obtain spiked samples, and the coincidence counts of three tubes of the spiked samples were measured using a liquid scintillation counter, with a measurement time of 20 minutes.

[0112] Take another 20mL low potassium glass scintillation bottle, add 10mL mineral oil and 10mL scintillation liquid to the low potassium glass scintillation bottle. Mix well and use it as the background sample. Use a liquid scintillation counter to measure the three tube coincidence counts of the background sample for the first time (T FF ), the measurement time is 4 hours, and then a liquid scintillation counter is used to measure the background sample for the second time. The three tube coincidence count (T FFB ), the measurement time is 20 minutes.

[0113] After measurement, the three-tube counting value of the sample to be tested was 31128, the three-tube counting value of the background sample measured for the first time was 6739, the three-tube counting value of the spiked sample was 542908, and the three-tube counting value of the background sample measured for the second time was 555. Figure 4The example 4 of the present application is shown. 14 C Peak area graph of the three tubes that meet the count value; The three tubes of spiked samples that meet the count value are Figure 4 Integration of the peak area.

[0114] The second measurement of the three tubes of the background sample coincides with the count (T FFB ) is for and join 14 The measurement time of the C standard substance and the spiked sample is consistent, and the three tubes of the background sample measured for the second time are counted according to the count (T FFB ) and the three-tube coincidence count of the spiked sample (T S ), the counting efficiency of the spiked sample was calculated by formula (1), and the counting efficiency was 90.4;

[0115] ε=(T S / t s -T FFB / t s ) / A formula (1)

[0116] In formula (1):

[0117] ε is the counting efficiency;

[0118] T S The three tubes of spiked samples are counted in compliance;

[0119] t s is the measurement time of the spiked sample;

[0120] T BF The three tubes of the sample to be tested are counted;

[0121] t BF is the measurement time of the sample to be tested;

[0122] A is 14 C is the activity of the standard substance.

[0123] The carbon content of the biofuel was measured using an elemental analyzer (Various MACRO cube) and was found to be 85.1%.

[0124] Combining the calculated counting efficiency (ε) and the carbon content of the sample (ω), the natural content of the biofuel is calculated according to formula (2):

[0125]

[0126] In formula (2):

[0127] N is the natural content of biofuel;

[0128] T BF The three tubes of the sample to be tested are counted;

[0129] T FF The three tubes for background samples are consistent with the count;

[0130] ε is the counting efficiency of the spiked sample;

[0131] t BF is the measurement time of the sample to be tested;

[0132] m represents the mass of biofuel;

[0133] ω represents the carbon content of biofuel.

[0134] The natural content of the biofuel sample was calculated to be 100%.

[0135] In liquid scintillation measurement, the chemical reaction will produce interfering light signals. 14 The C content is extremely low, so the real signal of the sample is weak, and the interference from chemiluminescence will be more serious. Usually, the interference is reduced by placing it away from light for a long time and waiting for the chemical reaction to end. The light-proof storage time is very long. The present application uses a liquid scintillation three-tube internal standard method to analyze the natural content in fuel. It does not need to be placed away from light for a long time and wait for the chemical reaction to end. The efficiency change during the measurement process is corrected by adding an internal standard substance of known activity to the sample to be tested. The natural content of biofuel is calculated based on the counting efficiency of the spiked sample and the carbon content of the biofuel. This method not only improves the accuracy and reliability of the measurement, but also can shield the chemiluminescence and photoluminescence of the sample to a large extent, shortening the analysis time.

[0136] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent substitutions, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A method for analyzing the naturalness of fuel using a liquid scintillation three-tube internal standard method, characterized in that: include: Add biofuel and scintillation liquid into the sample bottle to be tested and mix them evenly to obtain the sample to be tested, and use a liquid scintillation counter to measure the three-tube coincidence count of the sample to be tested; Add to the sample to be tested 14 C standard substance is used to obtain spiked samples, and a liquid scintillation counter is used to measure the coincidence counts of three tubes of the spiked samples; Add mineral oil and scintillation liquid into the background sample bottle and mix them evenly to obtain a background sample, and use a liquid scintillation counter to perform coincidence counting of three tubes of the background sample for the first measurement and three tubes of the background sample for the second measurement; The counting efficiency of the spiked sample is calculated based on the three-tube coincidence count of the spiked sample and the three-tube coincidence count of the background sample; the carbon content of the biofuel is measured using an elemental analyzer, and the natural content of the biofuel is calculated based on the counting efficiency of the spiked sample and the carbon content of the biofuel.

2. The method for analyzing the naturalness of fuel using a liquid scintillation three-tube internal standard method according to claim 1, characterized in that: The step of calculating the counting efficiency of the spiked sample according to the three-tube coincidence count of the spiked sample measured and the three-tube coincidence count of the background sample measured for the second time comprises: calculating the counting efficiency of the spiked sample according to formula (1); ε=(T S / t s -T FFB / t s ) / A Equation (1) In formula (1): ε is the counting efficiency; T S The three tubes of spiked samples are counted in compliance; t s is the measurement time of the spiked sample; T FFB The three tubes of the background sample for the second measurement are counted in accordance with the standard; A is 14 C is the activity of the standard substance.

3. The method for analyzing the naturalness of fuel using a liquid scintillation three-tube internal standard method according to claim 1, characterized in that: The method of calculating the natural content of the biofuel according to the three-tube coincidence count of the sample to be tested, the three-tube coincidence count of the background sample measured for the second time, the counting efficiency of the spiked sample and the carbon content of the biofuel comprises: calculating the natural content of the biofuel according to formula (2); In formula (2): N is the natural content of biofuel; T BF The three tubes of the sample to be tested are counted; T FF The three tubes of the background sample measured for the first time are counted in coincidence; ε is the counting efficiency of the spiked sample; t BF is the measurement time of the sample to be tested; m represents the mass of biofuel; ω represents the carbon content of biofuel.

4. The method for analyzing the naturalness of fuel using a liquid scintillation three-tube internal standard method according to claim 1, characterized in that: The time for measuring the sample using the liquid scintillation counter is 0.1-240 hours.

5. The method for analyzing the naturalness of fuel using a liquid scintillation three-tube internal standard method according to claim 1, characterized in that: The time for measuring the spiked sample using a liquid scintillation counter is 0.03-120 hours.

6. The method for analyzing the naturalness of fuel using a liquid scintillation triple tube internal standard method according to claim 1, characterized in that: The time for measuring the background sample for the first time using the liquid scintillation counter is 0.1-240 hours; the time for measuring the background sample for the second time using the liquid scintillation counter is 0.03-120 hours.

7. The method for analyzing the naturalness of fuel using a liquid scintillation three-tube internal standard method according to claim 1, characterized in that: The added volume ratio of the fuel sample to the scintillation fluid is 1:(1-2).

8. The method for analyzing the naturalness of fuel using a liquid scintillation three-tube internal standard method according to claim 1, characterized in that: The volume ratio of the mineral oil to the scintillation fluid is 1:(1-2).

9. The method for analyzing the naturalness of fuel using a liquid scintillation three-tube internal standard method according to claim 1, characterized in that: Said 14 The activity of C standard substances is 1-10000 Bq / mL.

10. Use of the method for analyzing the naturalness of fuel according to any one of claims 1 to 9 in analyzing the naturalness content of biofuel.

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