National Standard of China GB 23200.122-2026*, “National food safety standard – Determination of four pesticides including glyphosate and their metabolites residues in foods of plant origin – Liquid chromatography-tandem mass spectrometry method”, specifies the use of a quaternary ammonium-modified polyvinyl alcohol-based anion-exchange column or a column with equivalent performance. In this application, LC/MS/MS analyses of four phosphonic acid amino acid herbicides, including glyphosate and glufosinate, and six of their metabolites were performed using IC SI-50 4D.
Note: Although the GB method specifies the use of water for the preparation of N-methylglyphosate stock standard solution, the N-methylglyphosate reagent used in this application was insoluble in water and was therefore dissolved in 1 M NaOH aqueous solution. All other analytical conditions conformed to the GB method.
Preparation of standard solutions
- Dissolve N-methylglyphosate in 1 M NaOH aqueous solution and dissolve all other reagents in water to prepare individual stock standard solutions at 1000 mg/L.
- Mix the stock standard solutions and dilute with water to prepare a mixed intermediate standard solution at 50 mg/L.
- Dilute the mixed intermediate standard solution prepared in step 2 with water to prepare a mixed standard solution at 1 mg/L.
*The version at the time of the application acquisition.
Sample: 10 µL (Sample solution) 1 µg/mL each
- Phosphonic acid
- AMPA; Aminomethylphosphonic acid
- Ethephon
- MPPA; 3-Methylphosphinicopropionic acid
- N-Acetyl AMPA
- Glyphosate
- Glufosinate ammonium
- N-Methyl glyphosate
- N-Acetyl glyphosate
- N-Acetyl glufosinate
Column：Shodex IC SI-50 4D (4.0 mm I.D x 150 mm) Eluent：(A) H2O, (B) 200 mM NH4HCO3 + 30 mM NH3 aq. Gradient; 10 % B (0 to 0.5 min) to 40 % B (1 min) to 80 % B (4 min) to 82.5 % B (5 min) to 95 % B (6 to 12 min) to 10 % B (12.1 to 15 min) Flow rate：0.6 mL/min Detector：ESI-MS (negative, MRM) Column temp.：40 ℃