; (C) perfluoro[(2-pentafluoroethoxy-ethoxy)acetic acid] ammonium salt (Chemical Abstracts Service No. 908020–52–0); (D) 2,3,3,3-tetrafluoro 2-(1,1,2,3,3,3-hexafluoro)-2-(trifluoromethoxy) propanoyl fluoride (Chemical Abstracts Service No. 2479–75–6); (E) 2,3,3,3-tetrafluoro 2-(1,1,2,3,3,3-hexafluoro)-2-(trifluoromethoxy) propionic acid (Chemical Abstracts Service No. 2479–73–4); (F) 3H-perfluoro-3-[(3-methoxy-propoxy) propanoic acid] (Chemical Abstracts Service No. 919005–14–4); (G) the salts associated with the chemical described in subparagraph (F) (Chemical Abstracts Service Nos. 958445–44–8, 1087271–46–2, and NOCAS_892452); (H) 1-octanesulfonic acid 3,3,4,4,5,5,6,6,7,7,8,8-tridecafluoro-potassium salt (Chemical Abstracts Service No. 59587–38–1); (I) perfluorobutanesulfonic acid (Chemical Abstracts Service No. 375–73–5); (J) 1-Butanesulfonic acid, 1,1,2,2,3,3,4,4,4-nonafluoro-potassium salt (Chemical Abstracts Service No. 29420–49–3); (K) the component associated with the chemical described in subparagraph (J) (Chemical Abstracts Service No. 45187–15–3); (L) heptafluorobutyric acid (Chemical Abstracts Service No. 375–22–4); (M) perfluorohexanoic acid (Chemical Abstracts Service No. 307–24–4); (N) each perfluoroalkyl or polyfluoroalkly substance or class of perfluoroalkyl or polyfluoroalkyl substances for which a method to measure levels in drinking water has been validated by the Administrator