Chromatographic detection method for identifying purity of olive oil
The characteristic map of extra virgin olive oil was established through gas chromatography detection, which solved the problem of inaccurate identification of olive oil purity in the existing technology, achieved accurate identification and authenticity identification of extra virgin olive oil, and improved detection accuracy.
Patent Information
- Application Number
- CN202510045509.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-01-13
- Publication Date
- 2025-04-22
AI Technical Summary
It is difficult to accurately identify the purity of olive oil, especially extra virgin olive oil, and there are counterfeit and inferior products on the market, which reduces acidity by adding chemicals to impersonate extra virgin olive oil.
The gas chromatography detection method was used to establish the characteristic gas chromatograms of different varieties of extra virgin olive oil, and the sample to be inspected was tested. By comparing the similarity between the gas chromatogram and the characteristic map of the sample to be inspected, it was determined whether its purity meets the standards of extra primary olive oil.
It realizes accurate judgment of the purity of extra virgin olive oil, improves the accuracy of detection, avoids the impersonation of counterfeit and inferior products, and ensures the authenticity and quality of the product.
Abstract
Description
Technical Field
[0001] The invention belongs to the field of olive oil detection, in particular to a chromatographic detection method for identifying the purity of olive oil. Background Art
[0002] Olive oil is an edible oil extracted from olive fruit, which has many health benefits and functions such as lowering cholesterol, anti-oxidation, aiding digestion, and improving immunity. Olive oil is divided into virgin olive oil and refined olive oil. Since refined olive oil is extracted from olive pomace that has been squeezed once by chemical leaching, a small amount of chemical solvents may remain, and the nutrients are lost. Therefore, the quality and value of virgin olive oil are much higher than refined olive oil. At the same time, virgin olive oil is also divided into extra virgin olive oil, high-quality virgin olive oil and ordinary virgin olive oil. The main standard for judging the three is the acidity test. Extra virgin olive oil has an acidity of no more than 0.8%, high-quality virgin olive oil has an acidity of no more than 2%, and ordinary virgin olive oil has an acidity of no more than 3.3%. However, due to the high price of extra virgin olive oil, and the current market has a large number of fake olive oil products that pretend to be extra virgin olive oil by adding chemicals to reduce the acidity of olive oil, so the acidity test can no longer be used as the main standard for judging extra virgin olive oil. Therefore, there is currently a lack of a more accurate method for identifying the purity of olive oil. Summary of the invention
[0003] The invention provides a chromatographic detection method for identifying the purity of olive oil, which is used to solve the defects in the prior art.
[0004] The present invention is achieved through the following technical solutions:
[0005] A chromatographic detection method for identifying the purity of olive oil comprises the following steps:
[0006] Step 1: Using gas chromatography to detect different varieties of extra virgin olive oil, establish characteristic gas chromatograms of different varieties of extra virgin olive oil;
[0007] Step 2: Perform gas chromatography on the sample to be tested under the same gas chromatography detection conditions as step 1 and obtain a corresponding gas chromatogram;
[0008] Step 3: Compare the gas chromatogram of the sample to be tested with the characteristic gas chromatogram of the corresponding variety of extra virgin olive oil to determine whether its purity meets the purity standard of extra virgin olive oil.
[0009] In the chromatographic detection method for identifying the purity of olive oil as described above, the conditions for gas chromatography detection in step 1 are as follows: chromatographic column: DB-WAX123-7062, with specifications: 60m×0.32mm, 0.25μm; injection port temperature: 200°C; injection volume: 5μl; carrier gas: high-purity hydrogen; flow rate: 1.0ml / min; programmed temperature: initial temperature: 120°C; hold for 2min, increase to 200°C at a heating rate of 3°C / min, and hold for 6min.
[0010] In the above-mentioned chromatographic detection method for identifying the purity of olive oil, the sample preparation method of the chromatographic detection method in step 1 comprises the following steps:
[0011] Step 1: Accurately weigh 300 mg of olive oil and transfer it to a 10 ml volumetric flask, then add 2 ml of n-butane, 2 ml of methanol and 2 ml of potassium hydroxide solution and mix thoroughly;
[0012] Step 2: Add water to the volumetric flask to make up the volume, then add it to the gas chromatography injection bottle and tighten the bottle cap for injection testing.
[0013] In the chromatographic detection method for identifying the purity of olive oil as described above, the n-butane in step one is chromatographic grade n-butane, the methanol in step one is chromatographic grade methanol, and the water in step two is deionized water.
[0014] In the above-mentioned chromatographic detection method for identifying the purity of olive oil, the concentration of the potassium hydroxide solution in step 1 is 1 mol / L, and the solvent of the potassium hydroxide solution is deionized water.
[0015] In the chromatographic detection method for identifying the purity of olive oil as described above, in the process of establishing the corresponding spectra of different varieties of extra virgin olive oil in the step 1, each variety of extra virgin olive oil is subjected to ten consecutive gas chromatography detections, and the ten gas chromatograms of each variety of extra virgin olive oil are compared and analyzed. If the maximum error rate between them does not exceed 0.2%, the chromatogram located in the middle of all gas chromatograms as a whole is selected as the extra virgin olive oil of the corresponding variety; if the ten gas chromatograms of each variety of extra virgin olive oil are compared and analyzed, if the maximum error rate between them exceeds 0.2%, the gas chromatogram with a larger error is removed and then the chromatogram in the middle position is selected from the remaining gas chromatograms as the extra virgin olive oil of the corresponding variety; if there are more than three gas chromatograms with errors exceeding 0.2%, resampling is performed for gas chromatography detection and the above judgment is performed again.
[0016] In the chromatographic detection method for identifying the purity of olive oil as described above, the sample to be tested in step 2 is subjected to gas chromatography detection ten times and the obtained gas chromatogram is compared with the characteristic gas chromatogram of the corresponding variety. If the maximum error rate between all chromatograms and the characteristic chromatogram does not exceed 4%, the sample to be tested is identified as extra-pure virgin olive oil.
[0017] In the chromatographic detection method for identifying the purity of olive oil as described above, the number of gas chromatograms of the sample to be tested whose maximum error when compared with the characteristic gas chromatogram exceeds 4% does not exceed 3, and re-inspection is required when the maximum error when compared with the characteristic gas chromatogram does not exceed 10% to avoid errors caused by operational errors.
[0018] The advantages of the present invention are as follows: the present invention can accurately judge according to different substances contained in the extra virgin olive oils of different varieties of olives by establishing characteristic gas chromatograms of extra virgin olive oils of different varieties; then, the gas chromatogram obtained after gas chromatography detection of the olive oil sample to be detected is compared with the corresponding characteristic gas chromatogram to conveniently judge whether the sample to be detected is extra virgin olive oil; thus, the purity authenticity of the extra virgin olive oil can be quickly distinguished from the composition and the purity of the corresponding components, thereby improving the detection accuracy of the extra virgin olive oil. DETAILED DESCRIPTION
[0019] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described in combination with the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.
[0020] A chromatographic detection method for identifying the purity of olive oil comprises the following steps:
[0021] Step 1: Using gas chromatography to detect different varieties of extra virgin olive oil, establish characteristic gas chromatograms of different varieties of extra virgin olive oil;
[0022] Step 2: Perform gas chromatography on the sample to be tested under the same gas chromatography detection conditions as step 1 and obtain a corresponding gas chromatogram;
[0023] Step 3: Compare the gas chromatogram of the sample to be tested with the characteristic gas chromatogram of the corresponding variety of extra virgin olive oil to determine whether its purity meets the purity standard of extra virgin olive oil.
[0024] Specifically, the conditions for gas chromatography detection in step 1 described in this embodiment are: chromatographic column: DB-WAX123-7062, with specifications: 60m×0.32mm, 0.25μm; injection port temperature: 200°C; injection volume: 5μl; carrier gas: high-purity hydrogen; flow rate is 1.0ml / min; programmed temperature: initial temperature: 120°C; hold for 2min, increase to 200°C at a heating rate of 3°C / min, and hold for 6min.
[0025] Specifically, the sample preparation method of the chromatographic detection method in step 1 of this embodiment includes the following steps:
[0026] Step 1: Accurately weigh 300 mg of olive oil and transfer it to a 10 ml volumetric flask, then add 2 ml of n-butane, 2 ml of methanol and 2 ml of potassium hydroxide solution and mix thoroughly;
[0027] Step 2: Add water to the volumetric flask to make up the volume, then add it to the gas chromatography injection bottle and tighten the bottle cap for injection testing.
[0028] More specifically, the n-butane in step 1 of this embodiment is chromatographic grade n-butane, the methanol in step 1 is chromatographic grade methanol, and the water in step 2 is deionized water.
[0029] More specifically, the concentration of the potassium hydroxide solution in step 1 of this embodiment is 1 mol / L, and the solvent of the potassium hydroxide solution is deionized water.
[0030] Furthermore, in the process of establishing the corresponding spectra of different varieties of extra virgin olive oil in step 1 described in this embodiment, each variety of extra virgin olive oil is subjected to ten consecutive gas chromatography tests, and the ten gas chromatograms of each variety of extra virgin olive oil are compared and analyzed. If the maximum error rate between them does not exceed 0.2%, the chromatogram located in the middle of all gas chromatograms as a whole is selected as the extra virgin olive oil of the corresponding variety; if the ten gas chromatograms of each variety of extra virgin olive oil are compared and analyzed, if the maximum error rate between them exceeds 0.2%, the gas chromatogram with a larger error is removed and then the chromatogram in the middle position is selected from the remaining gas chromatograms as the extra virgin olive oil of the corresponding variety; if there are more than three gas chromatograms with errors exceeding 0.2%, resampling is performed for gas chromatography detection and the above judgment is performed again.
[0031] Furthermore, the sample to be tested in step 2 of this embodiment is subjected to gas chromatography detection ten times and the obtained gas chromatogram is compared with the characteristic gas chromatogram of the corresponding variety. If the maximum error rate between all chromatograms and the characteristic chromatogram does not exceed 4%, the sample to be tested is determined to be extra virgin olive oil.
[0032] Furthermore, the number of gas chromatograms of the samples to be tested described in this embodiment whose maximum error when compared with the characteristic gas chromatogram exceeds 4% does not exceed 3, and re-inspection is required when the maximum error when compared with the characteristic gas chromatogram does not exceed 10% to avoid errors caused by operational errors.
[0033] The olive oil detected by the chromatographic method of the present invention is subsequently analyzed by mass spectrometry to find that its error rate is less than 0.1%, thus greatly improving the detection accuracy of extra virgin olive oil.
[0034] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.
Claims
1. A chromatographic detection method for identifying the purity of olive oil, characterized in that: The steps include: Step 1: Using gas chromatography to detect different varieties of extra virgin olive oil, establish characteristic gas chromatograms of different varieties of extra virgin olive oil; Step 2: Perform gas chromatography on the sample to be tested under the same gas chromatography detection conditions as step 1 and obtain a corresponding gas chromatogram; Step 3: Compare the gas chromatogram of the sample to be tested with the characteristic gas chromatogram of the corresponding variety of extra virgin olive oil to determine whether its purity meets the purity standard of extra virgin olive oil.
2. The chromatographic detection method for identifying the purity of olive oil according to claim 1, characterized in that: The conditions for gas chromatography detection in the step 1 are as follows: chromatographic column: DB-WAX123-7062, with specifications: 60m×0.32mm, 0.25μm; injection port temperature: 200°C; injection volume: 5μl; carrier gas: high-purity hydrogen; flow rate: 1.0ml / min; programmed temperature: initial temperature: 120°C; hold for 2min, increase to 200°C at a heating rate of 3°C / min, and hold for 6min.
3. The chromatographic detection method for identifying the purity of olive oil according to claim 1, characterized in that: The sample preparation method of the chromatographic detection method in step 1 comprises the following steps: Step 1: Accurately weigh 300 mg of olive oil and transfer it to a 10 ml volumetric flask, then add 2 ml of n-butane, 2 ml of methanol and 2 ml of potassium hydroxide solution and mix thoroughly; Step 2: Add water to the volumetric flask to make up the volume, then add it to the gas chromatography injection bottle and tighten the bottle cap for injection testing.
4. The chromatographic detection method for identifying the purity of olive oil according to claim 3, characterized in that: The n-butane in step one is chromatographic grade n-butane, the methanol in step one is chromatographic grade methanol, and the water in step two is deionized water.
5. The chromatographic detection method for identifying the purity of olive oil according to claim 3, characterized in that: The concentration of the potassium hydroxide solution in step 1 is 1 mol / L, and the solvent of the potassium hydroxide solution is deionized water.
6. The chromatographic detection method for identifying the purity of olive oil according to claim 1, characterized in that: In the process of establishing the corresponding spectra of different varieties of extra virgin olive oil in the step 1, each variety of extra virgin olive oil is subjected to ten consecutive gas chromatography tests, and the ten gas chromatograms of each variety of extra virgin olive oil are compared and analyzed. If the maximum error rate between them does not exceed 0.2%, the chromatogram located in the middle of all gas chromatograms as a whole is selected as the extra virgin olive oil of the corresponding variety; if the ten gas chromatograms of each variety of extra virgin olive oil are compared and analyzed, if the maximum error rate between them exceeds 0.2%, the gas chromatogram with a larger error is removed, and then the chromatogram in the middle position is selected from the remaining gas chromatograms as the extra virgin olive oil of the corresponding variety; if there are more than three gas chromatograms with errors exceeding 0.2%, resampling is performed for gas chromatography detection and the above judgment is performed again.
7. The chromatographic detection method for identifying the purity of olive oil according to claim 1, characterized in that: The sample to be tested in step 2 is subjected to gas chromatography detection ten times and the obtained gas chromatogram is compared with the characteristic gas chromatogram of the corresponding variety. If the maximum error rate between all chromatograms and the characteristic chromatogram does not exceed 4%, the sample to be tested is identified as extra-purity virgin olive oil.
8. The chromatographic detection method for identifying the purity of olive oil according to claim 7, characterized in that: The number of gas chromatograms of the sample to be tested whose maximum error compared with the characteristic gas chromatogram exceeds 4% shall not exceed 3, and re-inspection is required when the maximum error compared with the characteristic gas chromatogram does not exceed 10% to avoid errors caused by operational errors.