N-Ethyl-N-(perfluoro-1-octanesulfonyl) Glycine-d5, is the labeled analogue of N-Ethyl-N-(perfluoro-1-octanesulfonyl) Glycine (E925518), used in biological study for transformation and bioaccumulation of N-Et perfluorooctane sulfonamide ethanol (N-EtFOSE) in soil-earthworm system.