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GB/T 35948-2018 (GB/T35948-2018)

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GB/T 35948-2018: PDF in English (GBT 35948-2018)

GB/T 35948-2018
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 71.100.70
Y 42
Determination of seven parabens in 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
Introduction ... 4
1 Scope ... 5
2 Normative references ... 5
3 Principle ... 5
4 Reagents and materials ... 6
5 Apparatus ... 6
6 Analytical procedures ... 7
7 Result calculation ... 9
8 Recovery and accuracy ... 9
9 Admissible error ... 9
Annex A (Informative) Chinese names, English names, CAS numbers,
molecular formulas, relative molecular masses and constitutional formulas of
paraben standard substances ... 10
Annex B (Informative) Liquid chromatograms and spectrograms of seven
paraben standard substance solutions ... 11
Determination of seven parabens in cosmetics -
High performance liquid chromatography
1 Scope
This Standard specifies the reagents and materials, apparatus, analytical procedures,
result calculation, recovery and accuracy, admissible error, etc. for the determination
of seven parabens in cosmetics using high performance liquid chromatography,
including propylparaben, isopropylparaben, butylparaben, isobutylparaben,
phenylparaben, benzylparaben and pentylparaben.
This Standard applies to the determination of seven parabens in cosmetics of creams,
emulsions, gels, waters, powders, wax base, including propylparaben,
isopropylparaben, butylparaben, isobutylparaben, phenylparaben, benzylparaben and
pentylparaben.
The method detection limits of this Standard. all the method detection limits of seven
parabens are 2 mg/kg.
The method quantitation limits of this Standard. all the method quantitation limits of
seven parabens are 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 Principle
Use ethanol 95% to extract sample of cosmetics of creams, emulsions, gels and waters;
use acetonitrile to extract sample of powder cosmetics; use cyclohexane to disperse
sample wax base cosmetics before using acetonitrile to extract; centrifuge and filter
extract before using high performance liquid chromatography for determination. Carry
out qualitative analysis based on the retention time and chromatogram and quantitative
6 Analytical procedures
6.1 Sample treatment
6.1.1 Sample of creams, emulsions, gels and waters
Weigh 0.5 g (accurate to 0.001 g) of sample to pour into a 10 mL graduated centrifugal
tube with a stopper; add 8 mL of ethanol 95% (4.3); vibrate to mix up on vortex mixer
(5.3); carry out ultrasonic extraction for 15 min; cool to room temperature; use ethanol
95% to add to metered volume of 10 mL. Take 2 mL of solution to a centrifugal tube;
centrifuge for 2 min at 10 000 r/min; carry out determination after filtering using filter
membrane (4.8).
6.1.2 Powder sample
Weigh 0.5 g (accurate to 0.001 g) of sample to pour into a 10 mL graduated centrifugal
tube with a stopper; add 4 mL of acetonitrile (4.2); vibrate on vortex mixer for 1 min;
carry out ultrasonic extraction for 15 min; centrifuge for 2 min at 2 000 r/min; transfer
all liquid supernatant to a 10 mL colorimetric tube; add 4 mL of acetonitrile (4.2) to
residuals to repeat extraction once; combine liquid supernatants; use acetonitrile (4.2)
to add to metered volume of 10 mL. Take 2 mL of solution to a centrifugal tube;
centrifuge for 2 min at 10 000 r/min; carry out determination after filtering using filter
membrane (4.8).
6.1.3 Wax base sample
Weigh 0.5 g (accurate to 0.001 g) of sample to pour into a 10 mL graduated centrifugal
tube with a stopper; add 2 mL of cyclohexane (4.4); vibrate to mix up on vortex mixer;
add 4 mL of acetonitrile (4.2) to vibrate on vortex mixer for 1 min; carry out ultrasonic
extraction for 15 min; centrifuge for 2 min at 2 000 r/min; transfer all liquid supernatant
to a 10 mL colorimetric tube; add 4 mL of acetonitrile (4.2) to residuals to repeat
extraction once; combine liquid supernatants; use acetonitrile (4.2) to add to metered
volume of 10 mL. Take 2 mL of solution to a centrifugal tube; centrifuge for 2 min at 10
000 r/min; carry out determination after filtering using filter membrane (4.8).
6.2 Determination
6.2.1 Reference working conditions for high performance liquid chromatography
The reference working conditions for high performance liquid chromatography are as
follows.
a) chromatographic column. core-shell type C18, 2.7 μm, 100 mm × 4.6 mm; or
equivalent;
7 Result calculation
The content of parabens in sample is calculated in accordance with the following
equation.
where.
Xi – the content tested constituents in sample, in mg/kg;
ci – the mass concentration of tested constituents in sample solution obtained from
standard curve, in mg/L;
c0 – the mass concentration of tested constituents in blank sample obtained from
standard curve, in mL;
V – the metered volume of sample solution, in mL;
m – the mass of sample, in g;
f – the dilution ratio.
Result is rounded off to two significant digits.
8 Recovery and accuracy
Within the range of adding concentration of 6 mg/kg ~ 60 mg/kg, the recovery is
between 85% ~ 110% and the relative standard deviation is less than 10%.
9 Admissible error
The absolute difference between the results of two tests which are obtained
independently under repeatable conditions, shall not exceed 10% of the arithmetic
mean value.
......
 
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