GB/T 22288-2008Determination of melamine, ammeline, ammelide and cyanuric acid in original plant products - GC-MS method (English PDF)

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.

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