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GB/T 35946-2018 (GB/T35946-2018)

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GB/T 35946-2018: PDF in English (GBT 35946-2018)

GB/T 35946-2018
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 71.100.70
Y 42
Determination of thimerosal in eye cosmetics -
High performance liquid chromatography
ISSUED ON. FEBRUARY 6, 2018
IMPLEMENTED ON. SEPTEMBER 1, 2018
Issued by. General Administration of Quality Supervision, Inspection and
Quarantine of the People's Republic of China;
Standardization Administration of the People's Republic of
China.
Table of Contents
Foreword ... 3
1 Scope ... 4
2 Normative references ... 4
3 Test method ... 4
4 Result calculation ... 8
5 Recovery and accuracy ... 8
6 Admissible error ... 8
Annex A (Informative) Chinese name, English name, INCI name, CAS
number, molecular formula, relative molecular mass and constitutional formula
of standard substance ... 9
Annex B (Informative) Chromatogram of thimerosal standard sample ... 10
Determination of thimerosal in eye cosmetics -
High performance liquid chromatography
1 Scope
This Standard specifies the test method, result calculation, recovery and accuracy,
tolerances, etc. for the determination of thimerosal in eye cosmetics using the high-
performance liquid chromatography.
This Standard applies to the determination of thimerosal in eye cosmetics, including
cleansing lotion, eye shadow, eye cream, mascara, liquid eyeliner, eyeliner cream and
eyebrow pencil.
The detection limits and quantitation limits of the Method of this Standard. the detection
limit of cleansing lotion is 1 mg/kg and the detection limit of eye shadow, eye cream,
liquid eyeliner, etc. is 2 mg/kg; the quantitation limit of cleansing lotion is 3 mg/kg and
the quantitation limit of eye shadow, eye cream, liquid eyeliner, etc. is 6 mg/kg.
2 Normative references
The following referenced documents are indispensable for the application of this
document. For dated references, only the edition dated applies to this document. For
undated references, the latest edition of the referenced documents (including all
amendments) applies to this document.
GB/T 6682, Water for analytical laboratory use – Specification and test methods
3 Test method
3.1 Principle
After extracting and centrifuging sample using methyl alcohol, use solid-phase
extraction cartridge to purify liquid supernatant; use the high-performance liquid
chromatography for determination and confirmation; use the external standard method
for quantitation.
3.2 Reagents and materials
3.2.14 Intermediate concentration thimerosal standard stock solution. 50 mg/L.
Accurately measure 0.5 mL of thimerosal standard stock solution (3.2.13); pour into a
10 mL volumetric flask; add formic acid methanol solution 10% (3.2.6) before adding
dropwise to scale; shake up; then obtain intermediate concentration thimerosal
standard stock solution of mass concentration 50 mg/L, which shall be prepared
immediately before use.
3.2.15 Thimerosal standard working solution. accurately measure a certain volume of
intermediate concentration thimerosal standard stock solution (3.2.14), respectively;
use formic acid methanol solution 10% (3.2.6) to prepare thimerosal standard working
solutions of different concentrations including 0 mg/L, 0.5 mg/L, 1.0 mg/L, 2.0 mg/L,
5.0 mg/L, 10 mg/L, 20 mg/L and 50 mg/L, which shall be prepared immediately before
use.
3.3 Apparatus
3.3.1 High performance liquid chromatograph (diode array detector).
3.3.2 Analytical balance. sensitivity 0.000 1 g.
3.3.3 Ultrasonic wave cleaner.
3.3.4 Solid phase extraction device.
3.3.5 Vortex mixer.
3.3.6 Centrifugal machine.
3.4 Sample preparation
3.4.1 Extraction
3.4.1.1 Eye cleansing lotion
Shake up sample; accurately weigh 0.5 g of sample; add 3 mL of methanol; vortex
disperse for 2 min; add methanol before adding dropwise to 5 mL to await purification.
3.4.1.2 Eye shadow, eye cream, mascara, eye gel, liquid eyeliner, eyeliner cream,
eyebrow pencil, etc.
Weigh about 0.5 g (accurate to 0.000 1 g) of sample; add 10.0 mL of methanol solution
(3.2.8) 50%; fully vibrate for 1 min (ultrasound-assisted dissolution can be carried out
for sticky sample); centrifuge for 5 min at 6 000 r/min; take 5 mL of liquid supernatant
to await purification.
3.4.2 Purification
......
 
(Above excerpt was released on 2019-02-16, modified on 2021-06-07, translated/reviewed by: Wayne Zheng et al.)
Source: https://www.chinesestandard.net/PDF.aspx/GBT35946-2018