Standard No.:	GB/T 40955-2021
English Name:	Determination of octamethylcyclotetrasiloxane(D4) and decamethylcyclopentasiloxane(D5) in cosmetics—Gas chromatography
Chinese Name:	化妆品中八甲基环四硅氧烷（D4）和十甲基环五硅氧烷（D5）的测定 气相色谱法
Chinese Classification:	Y42    Cosmetics
Professional Classification:	GB    National Standard
ICS Classification:	71.100.70 71.100.70    Cosmetics. Toiletries 71.100.70
Source Content Issued by:	SAMR; SAC
Issued on:	2021-11-26
Implemented on:	2022-6-1
Status:	valid
Target Language:	English
File Format:	PDF
Word Count:	6500 words
Translation Price(USD):	180.0
Delivery:	via email in 1 business day

Codeofchina.com is in charge of this English translation. In case of any doubt about the English translation, the Chinese original shall be considered authoritative. This document is developed in accordance with the rules given in GB/T 1.1-2020 Directives for Standardization — Part 1: Rules for the Structure and Drafting of Standardizing Documents. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. The issuing body of this document shall not be held responsible for identifying any or all such patent rights. This document was proposed by and is under the jurisdiction of National Technical Committee 374 on Products Test Methods of Standardization Administration of China (SAC/TC 374). Determination of Octamethylcyclotetrasiloxane (D4) and Decamethylcyclopentasiloxane (D5) in Cosmetics — Gas Chromatography 1 Scope This document specifies the principle, reagents and materials, apparatus, procedures, calculation of results, recovery rate and precision, and tolerance for the determination of octamethylcyclotetrasiloxane (D4) and decamethylcyclopentasiloxane (D5) in cosmetics by gas chromatography. This document is applicable to the determination of octamethylcyclotetrasiloxane (D4) and decamethylcyclopentasiloxane (D5) in aqueous solution, emulsion and cream (except waxy based cosmetics) in resident and rinsing cosmetics. 2 Normative References No normative reference is listed in this document. 3 Terms and Definitions No terms and definitions are listed in this document. 4 Principle The sample can be dispersed by isopropanol and extracted by n-hexane, then determined by gas chromatograph for qualitative retention time and quantitative by external standard method, and confirmed by gas chromatography-mass spectrometry if necessary. 5 Reagents and Materials Unless otherwise specified, only chromatographically pure reagents are used. 5.1 Isopropanol 5.2 n-Hexane. 5.3 Standard substance: purity ≥ 95%. Information on octmethylcyclotetrasiloxane (D4) and decamethylcyclopentasiloxane (D5) is given in Annex A. 5.4 Standard stock solution, 1000 μg/mL: take a proper amount of (to the nearest 0.0001 g) octmethylcyclotetrasiloxane (D4) and decamethylcyclopentasiloxane (D5) standard substance (5.3) in a volumetric flask, and mix with n-hexane (5.2) in constant volume. 5.5 Mixed standard working solution: a proper amount of standard stock solution (5.4) shall be transferred to a volumetric flask and diluted with n-hexane (5.2) step by step to a mixed standard working solution with mass concentrations of 0.5 μg/mL, 1.0 μg/mL, 5.0 μg/mL, 20.0 μg/mL, 50.0 μg/mL and 100.0 μg/mL. 5.6 Organic filter membrane: with a pore diameter of 0.22 μm.

Contents Foreword II 1 Scope 2 Normative References 3 Terms and Definitions 4 Principle 5 Reagents and Materials 6 Apparatus 7 Procedures 8 Calculation of Results 9 Recovery Rate and Precision 10 Tolerance Annex A (Informative) Information on Standard Substances Annex B (Informative) Gas Chromatograms of Standard Substances Octmethylcyclotetrasiloxane (D4) and Decamethylcyclopentasiloxane (D5) Annex C (Informative) Confirmatory Test