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GB/T 22288-2008 PDF in English


GB/T 22288-2008 (GB/T22288-2008, GBT 22288-2008, GBT22288-2008)
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GB/T 22288-2008: PDF in English (GBT 22288-2008)

GB/T 22288-2008
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 67.120
X 04
Determination of Melamine, Ammeline, Ammelide and
Cyanuric Acid in Original Plant Products - GC-MS Method
ISSUED ON. AUGUST 12, 2008
IMPLEMENTED ON. DECEMBER 1, 2008
Issued by. General Administration of Quality Supervision, Inspection and
Quarantine;
Standardization Administration of the People’s Republic of
China.
Table of Contents
Foreword ... 3 
1 Scope ... 4 
2 Principle ... 4 
3 Reagents and Materials ... 4 
4 Instruments and Equipment ... 5 
5 Sample Preparation and Preservation ... 5 
6 Analytical Procedure ... 5 
7 Result Calculation ... 8 
8 Minimum Limit of Determination ... 8 
9 Recovery Rate and Precision ... 8 
Appendix A (Informative) Retention Time, Selected Monitoring Ion and Relative
Abundance of Melamine, Ammeline, Ammelide and Cyanuric Acid ... 9 
Appendix B (Informative) Total Ion Chromatogram of Derivatives of Melamine,
Ammeline, Ammelide and Cyanuric Acid; Mass Spectrogram of the Derivatives
under Full Scan Mode ... 10 
Appendix C (Informative) Recovery Rate and Precision of Adding Melamine,
Ammeline, Ammelide and Cyanuric Acid to Wheat Flour, Corn Flour and Rice
Flour ... 13 
Determination of Melamine, Ammeline, Ammelide and
Cyanuric Acid in Original Plant Products - GC-MS Method
1 Scope
This Standard specifies gas chromatography - mass spectrometry method for the
determination of melamine, ammeline, ammelide and cyanuric acid in original plant
products.
This Standard is applicable to the determination of the content of melamine, ammeline,
ammelide and cyanuric acid in wheat flour, corn flour and rice flour.
2 Principle
Use solvent to extract sample. Use nitrogen blowing instrument to concentrate the
extract, then, use silanization reagent to derivatize it. Under selected ion monitoring
mode, use GC-MS to detect and determine melamine, ammeline, ammelide and
cyanuric acid. Use external standard method to quantify it.
3 Reagents and Materials
Unless it is otherwise stipulated, all reagents shall be analytical pure; water shall be
distilled water or water with equivalent purity.
3.1 Diethylamine.
3.2 Acetonitrile. chromatographically pure.
3.3 Pyridine. purity ≥ 99%.
3.4 Silanization reagent. contain 1% trimethylchlorosilane (TMCS) N, O-
bistrimethylsilyl trifluoroacetamide (BSTFA).
3.5 Extraction solvent. diethylamine - water - acetonitrile (10 + 40 + 50, volume ratio).
3.6 Melamine. purity ≥ 99.0%; CAS No.. 108-78-1.
3.7 Ammeline. purity ≥ 99.0%; CAS No.. 645-93-2.
3.8 Ammelide. purity ≥ 99.5%; CAS No.. 645-92-1.
3.9 Cyanuric acid. purity ≥ 99.0%; CAS No.. 108-80-5.
ultrasonic extraction for 30 min. Then, start centrifugation at 4,000 r/min for 5 min. Take
200 μL of supernatant, then, place it in 10 mL sharp-bottom glass colorimetric tube with
a plug. At 70 °C, use nitrogen to blow it, till it reaches dryness.
6.2 Derivatization
Add 300 μL of pyridine (3.3) and 200 μL of silanization reagent (3.4) to the colorimetric
tube, which is blown to dryness. Start ultrasound for 1 min; start vortex for 1 min, then
start derivatization at 70 °C for 45 min. The derivatized solution shall be used for the
gas chromatography - mass spectrometry determination.
6.3 Determination
6.3.1 Gas chromatography - mass spectrometry conditions
a) Chromatographic column. HP-5MS capillary column (30 m x 0.25 mm x 0.25
μm, 5%-phenyl-methyl polysiloxane) or equivalent;
b) Programmed temperature rise. initial temperature. 70 °C, maintain for 1 min; at
the rate of 15 °C/min, raise the temperature to 250 °C first; then, at the rate of
30 °C/min, raise the temperature to 300 °C, maintain for 5 min;
c) Injection port temperature. 280 °C;
d) Chromatography/mass spectrometry interface temperature. 280 °C;
e) Carrier gas. helium;
f) Flow rate. 1.0 mL/min;
g) Ionization mode. EI;
h) Ionization energy. 70 eV;
i) Ion source temperature. 230 °C;
j) Quadrupole temperature. 150 °C;
k) Monitoring mode. selected ion monitoring (SIM) mode;
l) Injection mode. splitless mode, solvent delay 6 min;
m) Injection volume. 1 μL;
n) Please refer to Appendix A for the retention time of analyte, monitoring ion and
relative abundance.
6.3.2 Standard working curve
7 Result Calculation
The content of the analyte in the sample shall be calculated in accordance with
Formula (1).
Where,
Xi---the content of the analyte in the sample, expressed in (mg/kg);
ci---the content of the analyte in the sample solution obtained through the standard
working curve, expressed in (ng/mL);
c0---the content of the analyte in the blank test obtained through the standard working
curve, expressed in (ng/mL);
V---the final constant volume of the sample solution, expressed in (mL);
s---dilution factor;
m---the mass of the sample being weighed, expressed in (g).
8 Minimum Limit of Determination
In this Method, the minimum limit of the determination of melamine, ammeline,
ammelide and cyanuric acid is 2.0 mg/kg.
9 Recovery Rate and Precision
Please refer to Appendix C for the data of recovery rate and precision.
......
 
Source: Above contents are excerpted from the PDF -- translated/reviewed by: www.chinesestandard.net / Wayne Zheng et al.