A method for identifying genuine and adulterated camellia oil

Abstract

The present invention relates to the technical field of detection methods, discloses a method for distinguishing true and false, adulterated camellia oil, comprising the following steps: adopting gas chromatography, taking campesterol and butyryl cetol as characteristic indicators for analysis, true camellia oil sample can not carry out qualitative and quantitative analysis on campesterol, can carry out qualitative and quantitative analysis on butyryl cetol, content is 1100~2000 mg / kg, thereby distinguishing true and false, adulterated camellia oil; wherein, butyryl cetol is analyzed by gas chromatography external standard method, and carrier gas is nitrogen; split ratio: 20‑40:1; column temperature adopts programmed temperature rise: 180‑190°C is maintained for 1‑5min, then warmed to 260‑300°C at 10‑15°C / min, maintained for 20‑40min. The present invention can quickly distinguish true and false, adulterated camellia oil by selecting campesterol and butyryl cetol as characteristic indicators, and the method is simple, the detection limit is low, and the accuracy rate is high.

Description

Technical Field

[0001] The invention relates to the technical field of detection methods, in particular to a method for identifying true and false camellia oil and adulterated camellia oil. Background Art

[0002] Camellia oil is an oil obtained from camellia seeds. Its oleic acid and linoleic acid content is as high as 90%, and it is known as the "Oriental Olive Oil". Studies have reported that camellia oil has a high oleic acid content, which can form a protective film on the skin surface to prevent the skin from excessive external stimulation. A large number of clinical, pharmacological and animal experiments have shown that tea polyphenols, squalene and other ingredients in camellia oil have anti-inflammatory and antioxidant effects, and have achieved good results for dermatitis, eczema, subacute / chronic erythema, inflammatory skin lesions with desquamation, and skin diseases manifested as dry skin (such as atopic dermatitis). Due to the scarcity, high price and high profit of camellia oil, other oils such as corn oil and soybean oil are blended with camellia oil. The fatty acid composition of these oils is quite different from that of camellia oil, and adulteration identification is relatively simple, which can be identified by fatty acid composition. However, for oils with fatty acid compositions that are very similar to camellia oil, such as high oleic sunflower oil and high oleic peanut oil, it is difficult to identify their adulteration when blended with camellia oil.

[0003] Patent CN 113834790 A discloses a method for detecting adulteration of camellia oil. Since different plant oils have different contents of active substances, the method is used to develop color with vanillin and then detect its absorbance value with an ultraviolet spectrophotometer for identification. This method is applicable to a certain extent, but its sensitivity is too low and its accuracy is poor.

[0004] Patent CN 101893553 A discloses a simple method for identifying the authenticity of camellia oil, which is designed based on the characteristic components of triterpenoid sapogenins in camellia oil. It uses the characteristic chemical reaction of triterpenoid sapogenins in camellia oil to identify the authenticity of camellia oil through thin layer chromatography and colorimetric tube colorimetric identification: color changes are presented to identify the authenticity of camellia oil. However, this method has low sensitivity in identifying adulterated oils.

[0005] Patent CN 102252972 B discloses a detection method for quickly identifying the true properties of camellia oil based on near-infrared spectroscopy. The spectral data of the camellia oil sample to be tested is collected using a near-infrared spectrometer. During the collection process, the near-infrared spectrum scanning wave number, near-infrared spectrum scanning times and resolution are controlled; then, the spectral band between 5750 and 6000 cm is selected in the collected standard spectrum. -1The data within the range is processed; finally, it is input into the camellia oil identification analysis model, and the Mahalanobis distance discriminant method is used to determine whether the sample point falls within the true sample area defined in the camellia oil identification analysis model, and the authenticity of the sample to be tested is determined accordingly. This method has a good identification effect on oils with large differences in fatty acid composition, but it is difficult to identify oils with small differences in fatty acid composition such as high oleic sunflower oil.

[0006] Patent CN110596287 A discloses a method for distinguishing Zhejiang safflower camellia oil from ordinary white camellia oil. The method distinguishes pure safflower and white camellia oils by detecting the contents of oleic acid, linoleic acid and behenic acid in the sample to be tested, but it is still difficult to distinguish adulteration of other oils.

[0007] In general, the methods for identifying camellia oil reported above are basically to detect its absorbance value by ultraviolet spectrophotometer, to identify by thin layer chromatography and colorimetric tube, to identify by infrared spectroscopy or to identify by different fatty acid composition. The sensitivity of ultraviolet spectrophotometer and colorimetric method is too low and the accuracy is poor. The method of infrared spectroscopy or different fatty acid composition can identify the fatty acids with large differences to a certain extent, but it is difficult to identify the vegetable oils with similar fatty acid composition. Therefore, there is still no good method to simultaneously identify the true and false and adulterated camellia oil. Summary of the invention

[0008] In order to solve the above technical problems, the present invention provides a method for identifying genuine, fake and adulterated camellia oil, which can identify genuine, fake and adulterated camellia oil by combining the differences in sterols and triterpenoid alcohols in different plant oils and fats, and conducts qualitative and quantitative analysis with campesterol and butyryl cetyl alcohol as characteristic indicators, so as to simply, quickly and accurately identify genuine, fake and adulterated camellia oil.

[0009] The purpose of the present invention is achieved through the following technical solutions:

[0010] The invention provides a method for identifying genuine and fake camellia oils, comprising the following steps: adopting gas chromatography to analyze campesterol and butyryl cetyl alcohol as characteristic indicators; a genuine camellia oil sample cannot be qualitatively and quantitatively analyzed for campesterol, but can be qualitatively and quantitatively analyzed for butyryl cetyl alcohol, and the content is 1100-2000 mg / kg, thereby identifying genuine and fake camellia oils; wherein butyryl cetyl alcohol is analyzed by gas chromatography external standard method, and the carrier gas is nitrogen; the split ratio is 20-40:1; the column temperature is programmed to rise: 180-190°C for 1-5 minutes, then the temperature is raised to 260-300°C at 10-15°C / min, and the temperature is maintained for 20-40 minutes.

[0011] The present invention distinguishes genuine and fake camellia oils through chromatographic analysis of sterols and triterpenoids. Specifically, qualitative and quantitative analysis is performed by selecting campesterol and butyryl cetyl alcohol as characteristic indicators. Qualitative analysis is to form a retention time in gas chromatography detection. Quantitative analysis needs to be based on qualitative analysis, and the peak area corresponding to the retention time is substituted into the standard curve to obtain the corresponding concentration. Campesterol is analyzed by reference to the standard "GB / T 25223-2010 Gas chromatography method for determination of sterol composition and total amount of sterols in animal and plant oils", and butyryl cetyl alcohol is analyzed by gas chromatography external standard method. In the gas chromatography external standard method, the separation degree of triterpenoids is better by optimizing instrument detection equipment parameters such as heating program, chromatographic column flow rate and detector temperature.

[0012] Camellia oil contains butyryl cetyl alcohol but not campesterol, and other vegetable oils except camellia oil contain campesterol but not butyryl cetyl alcohol, so the real camellia oil sample cannot be qualitatively analyzed for campesterol, but can be quantitatively analyzed for butyryl cetyl alcohol; the fake camellia oil sample cannot be qualitatively analyzed for butyryl cetyl alcohol, but can be quantitatively analyzed for campesterol; the adulterated camellia oil sample can be quantitatively analyzed for butyryl cetyl alcohol, and can also be qualitatively analyzed for campesterol. The method of the invention is simple, has a low detection limit, a high accuracy rate, and requires conventional and single equipment, and can simply, quickly and accurately identify the real and fake, and the adulterated camellia oil.

[0013] Preferably, the fake camellia oil sample is a single plant oil other than camellia oil.

[0014] Preferably, the camellia oil sample cannot be qualitatively and quantitatively analyzed for butyryl cetyl alcohol, but can be qualitatively and quantitatively analyzed for campesterol.

[0015] Preferably, the adulterated camellia oil sample is a mixture of camellia oil and a single or multiple vegetable oils other than camellia oil, and the adulteration determination limit is 1%.

[0016] Preferably, the adulterated camellia oil sample can be qualitatively analyzed for butyryl cetyl alcohol and campesterol, and can be quantitatively analyzed for at least one of butyryl cetyl alcohol and campesterol.

[0017] Preferably, the vegetable oil is sunflower oil, linseed oil, corn oil, soybean oil, rapeseed oil, peanut oil, grapeseed oil, high oleic peanut oil, high oleic rapeseed oil or high oleic sunflower oil.

[0018] Preferably, the gas chromatography external standard method comprises the following steps: placing the camellia oil sample to be tested in a colorimetric tube, adding a saponification solvent for saponification, and then extracting the saponified solution with n-hexane to obtain an extract; concentrating the extract to obtain a test solution.

[0019] Preferably, an HP-5 capillary chromatographic column is used, with specifications of 30m×0.32 mm×0.25 μm.

[0020] Preferably, the injection volume is 1 μL and the injection port temperature is 320-340°C.

[0021] Preferably, the air flow rate is 400 mL / min; the hydrogen flow rate is 40 mL / min; and the tail gas flow rate is 30 mL / min.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] (1) For the same camellia oil sample to be tested, the genuine and fake camellia oils can be quickly identified by selecting butyryl cetyl alcohol as the characteristic index, and the fake camellia oils with low adulteration levels can be identified by selecting campesterol as the characteristic index;

[0024] (2) The gas chromatography external standard method can achieve better separation of triterpene alcohols. By optimizing the instrument parameters, the sample pretreatment method is simplified and the required detection time is shortened.

[0025] (3) The method is simple, with a low detection limit and high accuracy. The required equipment is conventional and single, and it can simply, quickly and accurately identify genuine and adulterated camellia oil. DETAILED DESCRIPTION

[0026] The technical solution of the present invention is described below with specific embodiments, but the protection scope of the present invention is not limited thereto.

[0027] Example 1 (Standard Curve of Butyryl Cetyl Alcohol)

[0028] Triterpene alcohol standard information: butyryl cetyl alcohol (CAS No.: 559-70-6). The standard was purchased from Shanghai Anpu Laboratory Technology Co., Ltd. All standard solutions were prepared and used immediately.

[0029] Preparation of butyryl cetyl alcohol standard stock solution: Accurately weigh 5 mg (accurate to 0.1 mg) of butyryl cetyl alcohol standard into a 10 mL volumetric flask, dilute with toluene, dilute to scale, shake well, and prepare a final concentration of 500 μg / mL. Store at 0~4°C in the dark for future use. The recommended shelf life is 2 months. Dilute the butyryl cetyl alcohol standard stock solution into a series of standard solutions with different concentrations, namely 0, 5, 10, 20, 50, 100, 200 μg / mL, so that the actual test value of the sample is within the range of the standard curve.

[0030] Gas chromatography analysis conditions:

[0031] Gas chromatography column: HP-5 capillary column, column length 30m, inner diameter 0.32mm, film thickness 0.25μm;

[0032] Column flow rate: 1 mL / min;

[0033] Inlet temperature: 320°C;

[0034] Detector temperature: 300°C;

[0035] Injection volume: 1 μL;

[0036] Split ratio: 20:1;

[0037] Air flow rate: 400mL / min;

[0038] Hydrogen flow rate: 40mL / min;

[0039] Make-up gas flow rate: 30mL / min;

[0040] Carrier gas: high purity nitrogen (99.999%);

[0041] The column temperature was programmed: initially at 180 °C (held for 1 min), then increased from 180 °C to 260 °C at a rate of 15 °C / min and held for 35 min.

[0042] Accurately measure 1 μL of butyryl cetyl alcohol standard solution, inject it into the gas chromatograph, record the chromatogram, and draw a standard curve with the peak area as the ordinate and the concentration as the abscissa. The results are shown in Table 1.

[0043] Table 1

[0044]

[0045] Example 2 (Precision)

[0046] ① Weighing: Accurately weigh 0.1g camellia oil sample (accurate to 0.1mg) in a 25mL colorimetric tube;

[0047] ② Saponification: Add 5 mL of potassium hydroxide-ethanol solution to a 25 mL colorimetric tube, add the colorimetric tube to the rotor and place it on a magnetic stirrer at 80°C for saponification for 50 minutes, stop heating, remove and cool to room temperature, and add 5 mL of pure water;

[0048] ③Extraction: Extract the saponified solution in the colorimetric tube with 20 mL of n-hexane three times, let it stand for stratification, and then combine the extract into a 50 mL centrifuge tube;

[0049] ④ Washing: Wash the n-hexane extract with 10 mL of pure water each time, repeat the washing two to four times, discard the lower aqueous solution each time, and check with pH paper until the lower effluent is neutral;

[0050] ⑤ Concentrate and fix the volume: Put the neutralized n-hexane extract into a nitrogen blower and blow dry. Finally, dissolve it with n-hexane, sonicate, vortex and fix the volume to 3mL. Filter it with a 0.45μm organic filter head and put it on the machine.

[0051] The same batch of camellia oil samples were accurately weighed, a total of 6 portions, and a repeatability test was performed according to the gas chromatography parameters in Example 1, and the chromatogram was recorded with the peak area as the ordinate and the concentration as the abscissa. As shown in Table 2, the content results were calculated according to the standard curve, and the RSD result of butyryl cetyl alcohol did not exceed 5%, indicating that the precision result was good.

[0052] Table 2

[0053]

[0054] Example 3 (Reproducibility)

[0055] At different times, 6 samples of camellia oil from the same batch were accurately weighed, and a reproducibility test was performed according to the operating steps in Example 2. The chromatogram was recorded with the peak area as the ordinate and the concentration as the abscissa. As shown in Table 3, the content results were calculated according to the standard curve, and the RSD result of butyryl cetyl alcohol did not exceed 5%, indicating that the reproducibility results were good.

[0056] Table 3

[0057]

[0058] Example 4 (Comparison of different personnel)

[0059] Under the experimental operation of different personnel, the same batch of camellia oil samples were accurately weighed, a total of 6 parts, and the comparison test of different personnel was carried out according to the operating steps in Example 2, and the chromatogram was recorded, with the peak area as the ordinate and the concentration as the abscissa. As shown in Table 4, according to the content results calculated according to the standard curve, the RSD result of butyryl cetyl alcohol did not exceed 5%, indicating that the comparison results of different personnel were good.

[0060] Table 4

[0061]

[0062] Example 5 (spiked recovery)

[0063] ① Weighing: Accurately weigh 0.1g of camellia oil sample (accurate to 0.1mg) in a 25mL colorimetric tube, and add 1500mg / kg, 2250mg / kg, and 3000mg / kg of butyryl cetyl alcohol standard (relative to the concentration of camellia oil sample) respectively;

[0064] ② Saponification: Add 5 mL of potassium hydroxide-ethanol solution to a 25 mL colorimetric tube, add the colorimetric tube to the rotor and place it on a magnetic stirrer at 80°C for saponification for 50 minutes, stop heating, remove and cool to room temperature, and add 5 mL of pure water;

[0065] ③Extraction: Extract the saponified solution in the colorimetric tube with 20 mL of n-hexane three times, let it stand for stratification, and then combine the extract into a 50 mL centrifuge tube;

[0066] ④ Washing: Wash the n-hexane extract with 10 mL of pure water each time, repeat the washing two to four times, discard the lower aqueous solution each time, and check with pH paper until the lower effluent is neutral;

[0067] ⑤ Concentrate and fix the volume: Put the neutralized n-hexane extract into a nitrogen blower and blow dry. Finally, dissolve it with n-hexane, sonicate, vortex and fix the volume to 3mL. Filter it with a 0.45μm organic filter to obtain the test solution and put it on the machine.

[0068] The same batch of camellia oil samples were accurately weighed for spiked recovery test, and 6 parallel tests were performed for each concentration. As shown in Table 5, the average recovery rate of butyryl cetyl alcohol was greater than 92%, and the RSD was less than 5%, indicating good test results.

[0069] Table 5

[0070]

[0071] Example 6 (Identification of genuine and fake camellia oil)

[0072] 1. Taking campesterol as the characteristic index (reference standard "GB / T 25223-2010 Determination of sterol composition and total sterol content of animal and vegetable oils and fats - Gas chromatography")

[0073] ① Weighing: Weigh 0.75 g of sample into a 25 mL flask.

[0074] ② Preparation of alumina column: Add 10 g of alumina to 20 mL of ethanol and pour the suspension into a glass column to allow the alumina to settle naturally. Open the piston to release the solvent and close the piston when the liquid level reaches the top layer of alumina.

[0075] ③ Extraction of unsaponifiable matter: Accurately pipette 1.00 mL of 0.1 mg / mL betulin internal standard solution into the sample flask, then add 5 mL of potassium hydroxide-ethanol solution and zeolite. Connect the reflux condenser to the flask, heat and keep the mixture slightly boiling. After 15 minutes, stop heating, add 5 mL of ethanol to dilute the mixture in the flask while it is hot, and shake evenly.

[0076] Pipette 5 mL of the above solution and add it to the prepared alumina column. Collect the eluent in a 50 mL round-bottom flask, open the piston, and release the solvent until the liquid level reaches the top of the alumina. First elute the unsaponifiable matter with 5 mL of ethanol, then elute with 30 mL of ether at a flow rate of 2 mL / min, and remove the solvent in the flask with a rotary evaporator.

[0077] ④ Thin layer chromatography: Dissolve the unsaponifiable matter obtained with 5 mL of ether. Use a microsyringe to draw the solution and apply it 2 cm from the bottom edge of the thin layer plate. The sample solution should be applied in a line, and at least 3 cm should be left between the two ends of the line. Draw 5 μL of the thin layer chromatography standard solution and apply it 1.5 cm from the edge, one point on each side. Add about 100 mL of developing agent to the developing tank. Place the plate in the developing tank and develop until the solvent reaches the upper edge. Take out the thin layer plate and evaporate the solvent in a fume hood.

[0078] ⑤ Separation of sterols: Spray methanol on the thin layer chromatography plate until the sterol and betulin bands appear white against a translucent (dark) background, and the betulin spot is slightly lower than the sterol band. The marking includes the area 2 mm above the standard point and 4 mm below the visible spot area. Use a blade to scrape off the silica gel layer of all marked parts, and collect all the silica gel in a small beaker. Add 0.5 mL of ethanol to the collected silica gel. Elute the silica gel in the beaker three times with 5 mL of ether and filter into a flask. Concentrate the ether extract to about 1 mL using a rotary evaporator, transfer the concentrate to a reaction flask, and blow dry the solvent in the reaction flask with a stream of nitrogen.

[0079] ⑥ Preparation of sterol trimethylsilyl ether: Take 100 μL of silanization reagent (1:1 volume ratio of pyridine and N,O-bis(trimethylsilyl)trifluoroacetamide (containing trimethylchlorosilane) (99% BSTFA by mass + 1% TMCS by mass)) and add it to the reaction bottle of the concentrated solution. Seal the reaction bottle and heat it in a 105℃ oven for 15 min. After taking it out and cooling it to room temperature, inject the solution directly into the gas chromatograph for analysis.

[0080] Gas chromatography analysis conditions:

[0081] Gas chromatography column: stationary phase SE-54, column length 50m, inner diameter 0.25mm, film thickness 0.10μm;

[0082] Column flow rate: 1 mL / min;

[0083] Inlet temperature: 320°C;

[0084] Detector temperature: 320°C;

[0085] Injection volume: 1 μL;

[0086] Split ratio: 20:1;

[0087] Air flow rate: 400mL / min;

[0088] Hydrogen flow rate: 40mL / min;

[0089] Make-up gas flow rate: 30mL / min;

[0090] Carrier gas: high purity nitrogen (99.999%);

[0091] The column temperature was programmed: initially at 240°C, then increased from 240°C to 255°C at a rate of 4°C / min and maintained for 45 min.

[0092] 2. Using butyryl cetyl alcohol as characteristic indicator (gas chromatography external standard method)

[0093] ① Weighing: Accurately weigh 0.1g sample (accurate to 0.1mg) in a 25mL colorimetric tube;

[0094] ②Saponification: Add 5 mL of potassium hydroxide-ethanol solution to a 25 mL colorimetric tube, add the colorimetric tube to the rotor and place it on a magnetic stirrer at 80°C for saponification for 50 minutes, stop heating, remove and cool to room temperature, and add 5 mL of pure water.

[0095] ③Extraction: Extract the saponified solution in the colorimetric tube with 20 mL of n-hexane three times, let it stand for stratification, and then combine the extract into a 50 mL centrifuge tube;

[0096] ④ Washing: Wash the n-hexane extract with 10 mL of pure water each time, about two to four times, discard the lower aqueous solution each time, and check with pH test paper until the lower effluent is neutral;

[0097] ⑤ Concentrate and fix the volume: Put the neutralized n-hexane extract into a nitrogen blower and blow dry. Finally, dissolve it with n-hexane, sonicate, vortex and fix the volume to 3mL. Filter it with a 0.45μm organic filter head and wait for testing before loading it on the machine.

[0098] Gas chromatography analysis conditions:

[0099] Gas chromatography column: HP-5 capillary column, column length 30m, inner diameter 0.32mm, film thickness 0.25μm;

[0100] Column flow rate: 1 mL / min;

[0101] Inlet temperature: 320°C;

[0102] Detector temperature: 300°C;

[0103] Injection volume: 1 μL;

[0104] Split ratio: 20:1;

[0105] Air flow rate: 400mL / min;

[0106] Hydrogen flow rate: 40mL / min;

[0107] Make-up gas flow rate: 30mL / min;

[0108] Carrier gas: high purity nitrogen (99.999%);

[0109] The column temperature was programmed: initially at 180 °C (held for 1 min), then increased from 180 °C to 260 °C at a rate of 15 °C / min and held for 35 min.

[0110] The obtained gas chromatograms were used to qualitatively and quantitatively analyze the campesterol and butyryl cetyl alcohol of different samples, and the results are shown in Table 6. True camellia oil does not contain campesterol, but contains butyryl cetyl alcohol (content is 1100-2000 mg / kg), that is, butyryl cetyl alcohol can be qualitatively and quantitatively detected, but campesterol cannot be qualitatively and quantitatively detected. Other vegetable oils all contain high levels of campesterol, but do not contain butyryl cetyl alcohol, that is, campesterol can be qualitatively and quantitatively detected, but butyryl cetyl alcohol cannot be qualitatively and quantitatively detected. Therefore, for a single vegetable oil, whether campesterol and butyryl cetyl alcohol can be qualitatively and quantitatively analyzed can be used to simply identify true and false camellia oils.

[0111] Table 6

[0112]

[0113] Note: ND stands for cannot be determined qualitatively or quantitatively.

[0114] Example 7 (Identification of adulterated camellia oil)

[0115] According to the method in Example 6, different samples were qualitatively and quantitatively analyzed with campesterol and butyryl cetyl alcohol as characteristic indicators, and the results are shown in Table 7. When the mass proportion of adulterated oil is 1%, except for the campesterol signal-to-noise ratio of camellia oil <3, the campesterol signal-to-noise ratio of the remaining samples is >3. When the signal-to-noise ratio is <3, campesterol cannot be qualitatively and quantitatively detected. When the signal-to-noise ratio is >3, campesterol can be qualitatively detected using the retention time of campesterol, and there is no overlapping peak. When the signal-to-noise ratio is >10, campesterol can also be quantitatively detected. When camellia oil is mixed with 1% sunflower oil, corn oil, linseed oil, high oleic rapeseed oil or rapeseed oil, campesterol and butyryl cetyl alcohol can be qualitatively and quantitatively detected. Butyryl cetyl alcohol can be quantitatively detected in the remaining 1% adulterated samples, and campesterol can be qualitatively detected but not quantitatively. Therefore, the method of the present invention can effectively identify adulterated camellia oil, and the adulteration detection limit is 1%.

[0116] Table 7

[0117]

[0118] Example 8 (Identification of adulterated camellia oil)

[0119] According to the method in Example 6, qualitative and quantitative analysis was performed on different samples with campesterol and butyryl cetyl alcohol as characteristic indicators, and the results are shown in Table 8. When the mass proportion of adulterated oil is 5%, except for the campesterol signal-to-noise ratio of camellia oil <3, the campesterol signal-to-noise ratio of other samples is >3. In addition, except for the adulterated camellia oil sample doped with 5% high oleic sunflower oil, the campesterol signal-to-noise ratio of other adulterated camellia oil samples is >10, and all can be quantitatively detected. Although the adulterated camellia oil sample doped with 5% high oleic sunflower oil cannot be quantitatively detected, it can be qualitatively detected using the retention time of campesterol, indicating that 5% adulterated camellia oil can also be identified according to the method in the present invention.

[0120] Table 8

[0121]

[0122] The above are only preferred embodiments of the present invention, and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the specification of the present invention, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A method for identifying adulterated camellia oil, characterized in that: The method comprises the following steps: using gas chromatography to analyze campesterol and butyryl cetyl alcohol as characteristic indicators; the real camellia oil sample cannot be qualitatively and quantitatively analyzed for campesterol, but can be qualitatively and quantitatively analyzed for butyryl cetyl alcohol, and the content is 1100-2000 mg / kg, thereby identifying the adulterated camellia oil; the adulteration determination limit of the adulterated camellia oil sample is 1%; Among them, campesterol was analyzed by gas chromatography internal standard method, using a gas chromatography column with SE-54 as the stationary phase; the column temperature was programmed: initially 240°C, then increased from 240°C to 255°C at a rate of 4°C / min, and maintained for 45 minutes; Butyryl cetyl alcohol is analyzed by gas chromatography external standard method. The camellia oil sample to be tested is placed in a colorimetric tube, a saponification solvent is added for saponification, and then the saponification liquid is extracted with n-hexane to obtain an extract; the extract is concentrated and fixed to volume to obtain a test liquid, which is then tested and loaded onto a gas chromatographic machine; an HP-5 capillary column is used; the carrier gas is nitrogen; the split ratio is 20-40:1; the column temperature is programmed to rise: 180-190°C for 1-5 minutes, then raised to 260-300°C at a rate of 10-15°C / min and maintained for 20-40 minutes.

2. The method for identifying adulterated camellia oil according to claim 1, characterized in that: The adulterated camellia oil sample is a mixture of camellia oil and one or more vegetable oils other than camellia oil.

3. The method for identifying adulterated camellia oil according to claim 2, characterized in that: The adulterated camellia oil sample can be qualitatively analyzed for butyryl cetyl alcohol and campesterol, and can be quantitatively analyzed for at least one of butyryl cetyl alcohol and campesterol.

4. The method for identifying adulterated camellia oil according to claim 2, characterized in that: The vegetable oil is sunflower oil, linseed oil, corn oil, soybean oil, rapeseed oil, peanut oil, grapeseed oil, high oleic peanut oil, high oleic rapeseed oil or high oleic sunflower oil.

5. The method for identifying adulterated camellia oil according to claim 1, characterized in that: The specifications of the HP-5 capillary column are: 30m×0.32 mm×0.25μm.

6. The method for identifying adulterated camellia oil according to claim 1 or 5, characterized in that: Injection volume: 1 μL; Injection port temperature: 320-340°C.

7. The method for identifying adulterated camellia oil according to claim 1 or 5, characterized in that: Air flow rate: 400mL / min; Hydrogen flow rate: 40mL / min; Make-up gas flow rate: 30mL / min.

8. The method for identifying adulterated camellia oil according to claim 1 or 5, characterized in that: Column flow rate: 1mL / min.

9. The method for identifying adulterated camellia oil according to claim 1, characterized in that: The specifications of the gas chromatography column with SE-54 as the stationary phase are: 50m×0.25mm×0.10μm.

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