QB/T 2408-1998 Determination of vitamin E content in cosmetics

This standard specifies the use of thin layer chromatography to semi-quantitatively determine the content of vitamin E in cosmetics. This standard is applicable to the determination of vitamin E (including α-tocopherol and α-tocopherol acetate) in cosmetics. This standard does not apply to cosmetics containing both sunscreen and vitamin E (including α-tocopherol and α-tocopherol acetate). QB/T 2408-1998 Determination of vitamin E content in cosmetics QB/T2408-1998 Standard download decompression password: www.bzxz.net

QB/T 2408--1998
This standard is prepared in accordance with GB/T1.1-1993 "Guidelines for Standardization Work Unit 1: Rules for Drafting and Presentation of Standards Part 1: Basic Regulations for Standard Preparation". This standard is formulated based on the principle that the development speed of vitamin E in a mixed solvent on a silica gel GF254 chromatography plate is different from that of other substances, and the spots formed have absorption under ultraviolet light. This standard is proposed by the Industry Management Department of the State Bureau of Light Industry and is under the jurisdiction of the National Cosmetics Standardization Center. The drafting unit of this standard: Shanghai Daily Chemical Research Institute. The main drafters of this standard: Lin Yan, Han Meifang, Gan Pingping. 105
1 Scope
Light Industry Industry Standard of the People's Republic of Chinawww.bzxz.net
Determination of vitamin E in cosmetics
This standard specifies the semi-quantitative determination of vitamin E content in cosmetics by thin layer chromatography. QB/T2408—1998
This standard applies to the determination of vitamin E (including α-tocopherol and α-tocopherol acetate) in cosmetics. This standard does not apply to cosmetics containing both sunscreen and vitamin E (including α-tocopherol and α-tocopherol acetate). 2 Method Summary
After the sample is demulsified, extract it with petroleum ether to obtain the test sample. Spot the test sample and the standard sample on the silica gel GF254 chromatography plate at the same time, develop them in a mixed solvent of chloroform and cyclohexane, and visually inspect them under ultraviolet light. 3 Instruments
3.1 Ultraviolet lamp.
3.2 Chromatography cylinder: 25cmX16cmX30cm.
3.3 Thin layer chromatography preformed plate: silica gel GF254 chromatography plate 20cm×20cm. 3.4 Sample spotter: quantitative capillary 10μL. 3.5 Stoppered graduated test tube: 10mL.
3.6 Analytical balance: graduation value 0.001g.
4 Reagents
Analytical grade (AR) reagents should be used in the analysis. 4.1 month
Developing agent: chloroform: cyclohexane (3:2), shake well, and let it stand for 24 hours before use. 4.2 Petroleum ether (30℃～60℃).
4.3 Vitamin E reference solution (pure vitamin E content not less than 95%): accurately weigh 0.05g of standard vitamin E, dissolve in petroleum ether, and dilute in a 100mL volumetric flask. The concentration is 0.5μg/μL. 4.495% ethanol.
5 Determination steps
5.1 Preparation of sample
Accurately weigh about (1±0.02)g of sample into a 10mL graduated test tube, add 5mL of 95% ethanol, and place in a (60±2)℃ water bath for heating and shaking. After demulsification, add 5mL of petroleum ether, shake thoroughly, so that vitamin E is completely extracted in petroleum ether, and directly take the petroleum ether layer for spotting.
5.2 Chromatographic operation
According to the general thin layer chromatography operation, use a spotter to spot 10uL of the pre-prepared vitamin E standard sample on the silica gel GF chromatography plate (if α-vitamin E acetate is used as the standard sample, then spot 20μL), and then directly spot 100μL~120μL of the pre-treated sample petroleum ether solution in the interval between the standards (if α-vitamin E acetate is used as the standard sample, then drop 200μL) on the same chromatography plate. After spotting and drying naturally, place it in a developing solvent with a ratio of 3:2 of methyl chloride and cyclohexane. Unfold to a certain height, take out and place in a fume hood to dry, then place under ultraviolet light to compare the color spots at the same position of the vitamin E standard sample. Expression of results
Under specified conditions, if the color spot of the sample is the same as the color spot of the standard sample, it means that the content of vitamin E in the cosmetics is equivalent to 0.025%; if the color spot of the sample is lighter than the color spot of the standard sample, it means that the content of vitamin E in the sample is less than 0.025%; if the color spot of the sample is darker than the color spot of the standard sample, it means that the content of vitamin E in the sample is greater than 0.025%.
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