GB/T 7917.4-1987 English PDF
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GB/T 7917.4-1987: Standard methods of Hygienic test for cosmetics. Methanol
---This is an excerpt. Full copy of true-PDF in English version (including equations, symbols, images, flow-chart, tables, and figures etc.), auto-downloaded/delivered in 9 seconds, can be purchased online: https://www.ChineseStandard.net/PDF.aspx/GBT7917.4-1987NATIONAL STANDARD OF THE PEOPLE’S REPUBLIC OF CHINA UDC 668.58.543.062 GB 7917.4-87 Standard method of hygienic test for cosmetics - Methanol Issued on. MAY 28, 1987 Implemented on. OCTOBER 01, 1987 Issued by. Ministry of Health of the People's Republic of China
Table of Contents
1 Method summary... 3 2 Sample collection... 3 3 Reagents... 3 4 Instruments... 3 5 Analysis steps... 4 6 Calculation of analysis result... 5 Additional information... 6 Standard method of hygienic test for cosmetics - Methanol This Standard applies to the determination of methanol content in cosmetics that contain ethanol.1 Method summary
Use gas chromatography to test and quantify the samples directly or after distillation.2 Sample collection
See Chapter 2 of GB 7917.1-87, Standard methods of hygienic test for cosmetics - Mercury.3 Reagents
3.1 Methanol (99.5%). analytical reagent. 3.2 Methanol-free ethanol. inject 1.0 µl into the chromatograph, there shall be no impurity peaks. 3.3 GDX-102 (60 ~ 80 mesh). gas chromatography reagent. 3.4 Methanol standard solution. take 2.5 ml of methanol and place it in a 100 ml volumetric flask that is filled with 95 ml of water in advance; then, add water to the mark; mix well and set aside.4 Instruments
4.1 Gas chromatograph. it is equipped with hydrogen flame ionization detector. 4.2 Chromatographic column. glass column or stainless-steel column, whose specification is 2 m × Φ4 mm; it is filled with GDX-102 (60 ~ 80 mesh) supporter.5 Analysis steps
5.1 Start the chromatograph and make necessary adjustments to achieve the best working conditions of the instrument. Chromatographic conditions are selected according to specific conditions; the reference conditions are. 5.2 Sample pretreatment. for liquid or low-viscosity samples, and when the methanol content is high, take 10 ml of sample and add methanol-free ethanol (3.2) to a total volume of 50 ml. If necessary, it can be filtered and used as a sample liquid. The floral water with low methanol content can also be directly measured without dilution. 5.3 Determination Take four 50 ml volumetric flasks; respectively inject 1.00, 2.00, 3.00, 4.00 ml of methanol standard solution (3.4); then, respectively add 30 ml of methanol- free ethanol; respectively add water to the mark; this standard sequence contains methanol of 0.05%, 0.10%, 0,15%, 0.20%.6 Calculation of analysis result
Calculate the methanol concentration as follows. ......Source: Above contents are excerpted from the full-copy PDF -- translated/reviewed by: www.ChineseStandard.net / Wayne Zheng et al.
