Influence of Soil Physical and Chemical Properties on Detection of Glyphosate Residue.

In the soil environment, glyphosate is apt to get adsorbed to soil particles, and react with organic matter and metal oxides in the soil, which may affect detection of glyphosate. Influences of humic acid content, heavy metal ion content and pH of the soil on detection of glyphosate were explored,using the sodium phosphate and trisodium citrate aqueous supersonic extraction method, hexane purification method, 9-fluorenylmethylchloroformate (FMOC-l) derivatization method and HPLC-FLD. It turned out that recovery rate of glyphosate in soil decreased with increasing organic matter content, increased with increasing soil pH in the range of 3-11 (peaking at pH 8-9 and falling at pH over 9 back to the level at pH 7), decreased with the existence of heavy metal ions, such as Cu²⁺, Fe²⁺, Fe³⁺, Zn²⁺ and Ni²⁺ because they formed complexes with glyphosate, but was not affected by the existence of Co²⁺ and Mn²⁺. All the findings demonstrate that the standard detection method can meet the requirements for detecting glyphosate in various types of soils and sediments.