MF: C4 H F7 O2, MW: 214.04, Alternative Names: HFBA; Heptafluorobutanoic acid; Perfluorobutanoic acid; Perfluorobutyric acid; 2,2,3,3,4,4,4-Heptafluorobutanoic acid. Heptafluorobutyric Acid (HFBA) is an ion pairing agent for reverse-phase HPLC separation of peptides or proteins.