GB/T 40190-2021 English PDF (GBT40190-2021)

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GB/T 40190-2021: Determination of forbidden bleach in toothpaste - High performance liquid chromatography method
GB/T 40190-2021
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 71.040.40
Y 43
Determination of forbidden bleach in toothpaste - High
performance liquid chromatography method
ISSUED ON: MAY 21, 2021
IMPLEMENTED ON: DECEMBER 01, 2021
Issued by: State Administration for Market Regulation;
Standardization Administration of the People's Republic of
China.
Table of Contents
Foreword ... 3 
1 Scope ... 4 
2 Normative references ... 4 
3 Principle ... 4 
4 Reagents and standard materials ... 4 
5 Instruments ... 5 
6 Specimen preparation ... 5 
7 Determination by high performance liquid chromatography ... 5 
8 Result calculation ... 7 
9 Precision ... 7 
Annex A (informative) Liquid chromatogram of benzoyl peroxide standard
sample ... 8 
Determination of forbidden bleach in toothpaste - High
performance liquid chromatography method
1 Scope
This Standard specifies high performance liquid chromatography method to
determine the content of forbidden bleach - benzoyl peroxide - in toothpaste.
This Standard is applicable to the determination of the content of forbidden
bleach - benzoyl peroxide - in toothpaste.
The method detection limit of this Standard is 0.5mg/kg.
2 Normative references
The following referenced documents are indispensable for the application of
this document. For dated references, only the edition cited applies. For undated
references, the latest edition of the referenced document (including any
amendments) applies.
GB/T 6682-2008, Water for analytical laboratory use - Specification and test
methods
3 Principle
Acetonitrile for samples: After water extraction (80:20, volume ratio), after the
supernatant is filtered through a 0.45μm filter membrane, use post-column
derivatization-high performance liquid chromatography-fluorescence detection
method to determine. Use external standard peak area method to quantify.
4 Reagents and standard materials
Unless otherwise specified, all reagents used are analytically-pure AND water
is grade one water specified in GB/T 6682-2008.
4.1 Acetonitrile: chromatographically pure.
4.2 Hemin: mass fraction ≥98.0%.
4.3 P-hydroxyphenylacetic acid: mass fraction ≥98.0%.
(250mm×4.6mm×5μm).
b) Fluorescence detector wavelength: excitation wavelength is 315nm,
emission wavelength is 400nm.
c) Mobile phase: methanol with 0.1% acetic acid: water (85:15, volume ratio).
d) Flow rate: 0.6mL/min.
e) Column temperature: 20°C.
f) Injection volume: 10μL.
g) Derivative conditions: The derivatization reagent are 8μmol/L hemin and
80μmol/L p-hydroxyphenylacetic acid in NH4Cl-NH3·H2O buffer solution
(pH=10.5). The back pressure of the post-column derivative is
500psi~1000psi or the flow rate is 0.2mL/min. The temperature of the
reaction tube is 35°C.
7.2 Preparation of standard working solution
Accurately pipette 1.0mL, 2.0mL, 4.0mL, 8.0mL, 10.0mL of standard stock
solution (4.6) in a 100mL volumetric flask. Use acetonitrile to dilute to the scale
mark. Shake well. Filter it by 0.45μm filter membrane for future use. At this time,
the mass concentration of the standard series solution is 10.0 mg/L, 20.0 mg/L,
40.0 mg/L, 80.0 mg/L, 100.0 mg/L. Under the set chromatographic conditions
(7.1), respectively take 10μL for analysis. Take the mass concentration of the
standard series solution as the abscissa (mg/L), the peak area of the reference
substance as the ordinate to draw the calibration curve (linear correlation
coefficient R≥0.9990). Refer to Figure A.1 in Annex A for the liquid
chromatogram of benzoyl peroxide standard sample.
7.3 Determination steps
After the sample is processed according to the steps in Chapter 6, perform on-
board testing according to the instrument conditions of 7.1. The response value
of benzoyl peroxide in the test sample solution shall be within the linear range
of the standard curve. If it exceeds the linear range, it shall be diluted before
injection for determination.
7.4 Blank test
Except not adding specimen, all are tested in accordance with the processing
steps in Chapter 6 and the instrument conditions in 7.1.