Time-integrated sampling of glyphosate in natural waters

► Glyphosate losses are likely in monitoring programs using time-integrated sampling. ► Losses are partly due to degradation, partly to binding to metals or humus. ► Refrigerated time-integrating samplers reduces degradation and increases recovery. ► Acidification during sampling increases recovery by reversing metal and humus binding. ► Labelled surrogate standards are imperative to identify false negatives.