GB/T 37560-2019 English PDF (GBT37560-2019)

This Standard specifies the determination method, accuracy and precision of melamine and cyanuric acid in melamine cyanurate for flame retardant. This Standard is applicable to the determination of melamine and cyanuric acid in melamine cyanurate by liquid chromatography external standard quantitative method.

GB/T 37560-2019
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 71.040.50
G 70
Flame retardant chemicals - Determination of
melamine and cyanuric acid in melamine cyanurate
ISSUED ON: JUNE 04, 2019
IMPLEMENTED ON: MAY 01, 2020
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 General ... 4
4 Determination of melamine content ... 4
5 Determination of cyanuric acid content ... 7
6 Accuracy and precision of the method ... 9
Flame retardant chemicals - Determination of
melamine and cyanuric acid in melamine cyanurate
1 Scope
This Standard specifies the determination method, accuracy and precision of melamine and cyanuric acid in melamine cyanurate for flame retardant.
This Standard is applicable to the determination of melamine and cyanuric acid in melamine cyanurate by liquid chromatography external standard quantitative method.
The detection-limit of this method: cyanuric acid content ≥ 0.002 0 µg/mL; melamine content ≥ 0.007 8 µg/mL.
2 Normative references
The following documents are indispensable for the application of this document. For dated references, only the dated version applies to this document. For undated references, the latest edition (including all amendments) applies to this document.
GB/T 33087, Ultra-pure water for instrumental analysis specification and test methods
3 General
The reagents and water used in this Standard refer to chromatographic pure reagents and ultra-purity water for instrumental analysis in accordance with GB/ T 33087 when no other requirements are specified.
4 Determination of melamine content
4.1 Method summary
Use water at 50°C to dissolve the residual cyanuric acid and melamine in the sample; cool and filter; take the filtrate; use liquid chromatography external standard method for quantitative analysis.
4.2 Reagents and materials
4.2.1 Methanol.
4.5.1 Drawing of the standard curve
Take melamine standard stock solution; use the mobile phase to dilute into standard solutions of which the mass concentrations are 0 μg/mL, 0.2 μg/mL, 0.4 μg/mL, 0.8 μg/mL, 1.0 μg/mL, 2.0 μg/mL, 5.0 μg/mL, 10.0 μg/mL, 20.0 μg/mL, and 50.0 μg/mL. Inject and detect the standard solutions sequentially; plot the peak area-mass concentration, to obtain a standard curve regression equation.
4.5.2 Processing and determination of samples
Weigh 1 g (accurate to 0.1 mg) of melamine cyanuric acid sample into a 100 mL beaker; add 50 mL of water; incubate in a constant-temperature shaking bath at 50°C for 10 min ~ 15 min; use medium-speed quantitative filter paper to filter when it is hot; use water at 50°C to rinse off the beaker and the funnel; collect the filtrate in a 100 mL volumetric flask; rinse and fix-volume to the scale. This solution is the to-be-test solution A. Take a certain amount of the to-be-test solution A to perform measurement; record the chromatographic peak area; calculate the mass concentration according to the standard curve. Do a blank test at the same time.
4.6 Test data processing
The melamine content X1 (%) which is expressed in mass fraction is calculated according to Formula (1):
Where:
ρ -- the mass concentration of melamine in the sample solution, in micrograms per milliliter (μg/mL);
ρ0 -- the mass concentration of melamine in the blank solution, in micrograms per milliliter (μg/mL);
m -- sample mass, in grams (g).
V -- sample volume, in milliliters (mL);
1 000 000 -- the value when gram (g) is converted to microgram (μg).
Take the arithmetic mean of the results of two parallel tests as the measurement result; the absolute difference between the results of the two parallel tests is not more than 0.03%.
5.4 Test conditions
5.4.1 Column: C18 reverse phase column, 250 mm × 4.6 mm × 5 μm; or other columns that can reach the test conditions.
5.4.2 Detection wavelength: 220 nm.
5.4.3 Flow velocity: 1.0 mL/min.
5.4.4 Injection volume: 20 μL;
5.5 Test steps
5.5.1 Drawing of the standard curve
Take cyanuric acid standard stock solution; use the mobile phase to dilute into standard solutions of which the mass concentrations are 0 μg/mL, 2.0 μg/mL, 5.0 μg/mL, 10.0 μg/mL, 20.0 μg/mL, 40.0 μg/mL, 50.0 μg/mL, 60.0 μg/mL, 80.0 μg/mL, and 100.0 μg/mL. Inject and detect the standard solutions sequentially; plot the peak area-mass concentration, to obtain a standard curve regression equation.
5.5.2 Processing and determination of samples
Take a certain amount of the to-be-test solution A which is gained from 4.5.2 to perform measurement; record the chromatographic peak area; calculate the mass concentration according to the standard curve. Do a blank test at the same time.
5.6 Test data processing
The cyanuric acid content X2 (%) which is expressed in mass fraction is calculated according to Formula (2):
Where:
ρ -- the mass concentration of cyanuric acid in the sample solution, in micrograms per milliliter (μg/mL);
ρ0 -- the mass concentration of cyanuric acid in the blank solution, in micrograms per milliliter (μg/mL);
m -- sample mass, in grams (g).
V -- sample volume, in milliliters (mL);