Glyphosate

Method Description

Glyphosate is a broad-spectrum herbicide widely applied to crops such as corn, soybeans, and oats, and may also be used as a pre-harvest desiccant. In soil, glyphosate can degrade microbially to aminomethylphosphonic acid (AMPA). AMPA may also be taken up by biota, but is typically present at lower concentrations than glyphosate. Glyphosate and AMPA are highly polar, zwitterionic compounds that require specialized extraction and chromatographic conditions beyond those used in traditional multi-residue analysis (MRA) methods. Samples are extracted using an acidified solvent containing a chelating agent to precipitate proteins and bind metal ions that may interact with the target analytes. The extract is then cleaned by solid-phase extraction and analyzed by liquid chromatography–tandem mass spectrometry (LC-MS/MS) using solvent-based calibration. Please provide a detailed sample matrix description to support appropriate crop group determination (for example, apple juice rather than fruit juice). Accurate sample descriptions and concentration estimates are recommended.