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GB/T 7917.4-1987 PDF in English


GB/T 7917.4-1987 (GB/T7917.4-1987, GBT 7917.4-1987, GBT7917.4-1987)
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GB/T 7917.4-1987: PDF in English (GBT 7917.4-1987)

GB 7917.4-1987
NATIONAL 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. This solution is a 2.5% methanol solution.
3.5 Sodium chloride: analytical reagent.
3.6 Defoamer: emulsified silicone oil, such as 284PS, that is produced by
Shanghai Resin Factory.
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.
5.2 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. If the viscosity of the sample is too large to be
measured directly, take 10 g of sample and place it in a distilling bottle (as
shown); add 50 ml of water, 2 g of sodium chloride (3.5), and 1 drop of defoamer
(3.6) if necessary; then, add 30 ml of methanol-free ethanol (3.2); distill in the
boiling water bath; collect about 40 ml of distillate in a 50 ml volumetric flask;
after cooling to room temperature, add methanol-free ethanol (3.2) to the mark
as a sample solution.
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%.
Take standards from each volumetric flask in turn and inject them into the gas
chromatograph; record the area of each chromatogram; draw the peak area-
methanol concentration (V/V) curve.
Take 1 µl of the sample solution that is prepared in 5.2; inject it into the gas
chromatograph; record the chromatographic peak area; find out the
corresponding methanol concentration from the standard curve.
6 Calculation of analysis result
Calculate the methanol concentration as follows:
Methanol (%, V/V) =
Where:
P -- the methanol concentration of the sample solution that is found from the
standard curve, %
K -- dilution factor of the sample, the dilution factor is according to this
method. When the sample is subjected to distillation, the dilution factor is
also regarded as .
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Source: Above contents are excerpted from the PDF -- translated/reviewed by: www.chinesestandard.net / Wayne Zheng et al.