The determination of glyphosate at trace level is unquestionably complicated. However, if the correct analytical method is chosen, rather effective results can be achieved. In our case, the choice of isotope dilution quantification has allowed us to achieve a good yield without having to worry about potential losses during the rapid stage (1 min) of simultaneous extraction-purification. Derivatisation has been a success since it allows us to easily incorporate the analysis of glyphosate into routine analyses without making any changes instrumentally, which therefore represents a considerable time saving benefit.