Agricultural Industry Standard of the People's Republic of China
ny/t 4305-2023
vegetable oilDimethoxyDetermination of vinylphenolHigh performance liquid chromatography
determination of 26-dimethoxy-4-vinylphenol in vegetable oils-
high performance liquid chromatography
Foreword
This document is in accordance with GB T 11-2020 "Guidelines for Standardization Work Part 1: Structure and Drafting Rules of Standardization Documents".
This document is presented by the Department of Rural Industry Development of the Ministry of Agriculture and Rural Affairs.
This document is under the control of the Technical Committee on Agricultural Products and Standardization of the Ministry of Agriculture and Rural Affairs.
This document was drafted by: Oil Crops Research Institute of Chinese Academy of Agricultural Sciences, Tianjin Academy of Agricultural Sciences, and Quality Supervision, Inspection and Testing Center for Agricultural Products and Processed Products of the Ministry of Agriculture and Rural Affairs (Tianjin).
The main drafters of this document: Huang Fenghong, Zheng Chang, Li Wenlin, Liu Changsheng, Wan Chuyun, Zhou Qi, Zhang Qiang, Wei Fang, Zheng Mingming, Liu Zhenghui, Chen Qiusheng.
Scope
This document specifies a method for the determination of 2,6-dimethoxy-4-vinylphenol in vegetable oils and blended oils.
This document is applicable to the determination of 2,6-dimethoxy-4-vinylphenol in vegetable oils and blended oils.
The detection limit of the method in this document is 110 mg kg, the limit of quantification is 320 mg/kg。
Normative references
The content of the following documents constitutes an essential provision of this document by means of normative references in the text. Among them, the reference document with the date is noted, and only the version corresponding to that date applies to this document;For undated citations, the latest copyright (including all amendments) applies to this document.
Preparation of preparations and products used in the test method of GB T 603 chemical reagents.
GB T 5524 Animal and vegetable oils and fats Samples.
GB T 6682 Analytical Laboratory Water Specifications and Test Methods.
Principle
The 2,6-dimethoxy-4-vinylphenol in vegetable oil was extracted by a mixed solution of methanol and n-hexane, and then determined by a high-performance liquid chromatograph equipped with a diode array detector, and the retention time was qualitative, and the external standard method was quantified.
Reagents and materials
Unless otherwise stated, the reagents used are analytically pure, and the water used is the first-class water specified in GB T 6682. Boil for 10 min before use and then cool. The utensils used are washed with water and dried in a 100 oven for 1 2h.
4.1 methanol (chromatographically pure).
4.2 n-hexane.
4.3. Acetic acid.
4.4 1% acetic acid water: Accurately aspirate 10 ml acetic acid (4.)3) Add water to 100 ml.
4.5 methanol + water (80 + 20): take 80ml of methanol (4.)1) Use 20ml of water and mix well.
4.6 2,6-dimethoxy-4-vinylphenol (C10H12O3, CAS No. 28343-22-8): 98% purity.
4.7 2,6 dimethoxy-4-vinylphenol standard solution preparation;
4.7.1 standard stock solution: precision weighing 100 mg 2.6-Dimethoxy-4-vinylphenol (4.)6) Standards, plus methanol (4.)1) Dissolve and set the volume in a 10 ml brown volumetric flask to a concentration of 10 mg ml standard stock solution, -20 or less protect from light.
4.7.2. Standard working solution: Pipette a certain amount of 2,6-dimethoxy-4-vinylphenol standard stock solution (47.1) with methanol solution (45) The concentration obtained by dilution is 50 μg/ml、10.0 μg/ml、 20.0 μg/ml、50.0 μg/ml、100.0 μg/ ml、200.0 g ml and 5000 g ml of standard working solution. Ready-to-use.
Instruments and equipment
5.1 High Performance Liquid Chromatograph: Equipped with diode array detector (PDA) or ultraviolet detector (UVD).
5.2 Analytical Balance: Inductance 00001 g。
5.3 Centrifuge: speed not less than 5 000 r min.
5.4. Vortex shaker.
5.5 Microporous membrane: 022 m, organic faculty.
Sampling and specimen preservation
6.1 Sampling.
Sampling is carried out in accordance with GB T 5524, and samples received by the laboratory should be truly representative and have not been damaged or deteriorated during transportation and storage.
6.2 Save.
The specimen should be stored in a refrigerator below 4 years old in the dark.
Assay steps
7.1. Preparation of the sample.
Weigh about 1 g (accurate to 0.).001 g) sample in a 10 ml centrifuge tube, add 15 ml n-hexane (42) and 15 ml of methanol solution (4.)5), vortex extraction for 5min, centrifuge at 5000r min for 5min to retain the lower extraction, transfer the upper solution to another 10ml centrifuge tube, and continue to add methanol solution to the upper solution (45), repeat the extraction 3 times, combine the lower extract, mix well, centrifuge at 5 0000 r min for 5 min, absorb the residual sample solution of the upper layer, transfer the lower extract solution to a 10 ml volumetric flask, and use methanol solution (45) Set the volume to the scale, shake well, pass the film, and store under 4 conditions for later use.
7.2 Assay conditions.
7.2.1 Liquid chromatography reference conditions.
Column: C18 (I.D. 4.)6 mm, particle size 5 m, column length 250 mm);
Mobile phase: A is methanol (41), b is 1% acetic acid water (44）；
Flow rate: 10 ml/min；
Column temperature: 30;
Injection volume: 10 l;
Detection wavelength: 270 nm.
The mobile phase gradient elution procedure is shown in Table 1.
7.3. Chromatographic determination.
When the linear range is exceeded, an appropriate factor dilution should be carried out according to the measured concentration before analysis, and the response value of 2,6-dimethoxy-4-vinylphenol in the standard curve solution should be within the appropriate range of the instrument. The peak area of the content response was taken as the ordinate and the content of 2,6-dimethoxy-4-vinylphenol was used as the abscissa, and the standard L was plotted as the curve. The retention time is qualitative, and the external standard is quantified.
7.4. Calculation and presentation of results.
The content of 2,6-dimethoxy-4-vinylphenol in the sample is calculated according to equation (1) or calculated by a chromatographic data processing system.
where: x - the value of the content of 2,6-dimethoxy-4-vinylphenol in the sample, in milligrams per kilogram (mg kg);
c - 2,6-dimethoxy-4-vinylphenol concentration in micrograms per milliliter (g ml) of the sample solution obtained from the standard working curve;
v——The value of the final volume of the sample solution, in milliliters (ml);
m - the numerical value of the mass of the sample represented by the sample solution, in grams (g).
The results of the calculations are expressed as the arithmetic mean of parallel measurements, and the results are kept to 2 decimal places.
Precision
The absolute difference between the results of the 2 independent assays obtained under repeatability conditions must not exceed 10% of the arithmetic mean.
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