1 Scope
This standard specifies the determination method of the residues of diquat in cereals.
This standard is applicable to the determination of residues of diquat in corn and barley.
The detection limit of this standard is 0.005mg/kg and the linear range is 0.001mg/L~0.100mg/L.
2 Principle
According to diquat's solubility and stability, extract diquat with 95% ethanol; make it react with sodium borohydride and extract with trichloromethane; remove the trichloromethane and bring to volume with n-hexane; then determine with gas chromatography - mass spectrometry detector and quantify by external standard method; confirm and quantify via selected ion monitoring.
Foreword i
1 Scope 1
2 Principle 1
3 Reagents and Materials 1
4 Apparatus 2
5 Analytical Procedure 2
6 Calculation of Result 3
7 Precision 4
Appendix A (Informative) Gas Chromatogram - Mass Spectrogram of Diquat Standard Substance 5
