Results for PFOS analysis with detailed methods. This dataset is associated with the following publication: Wang, Y., H. Jang, M. Topel, S. Dasetty, Y. Liu, M. Ateia, A. Tam, V. Rozyyev, E. Ouyang, W. Zhuang, H. Pu, S.S. Lee, X. Sui, J.W. Elam, A.L. Ferguson, S.B. Darling, and J. Chen. Reversible parts-per-trillion-level detection of perfluorooctane sulfonic acid in tap water using field-effect transistor sensors. Nature Water. Nature Portfolio, Berlin, GERMANY, 3: 1187-1197, (2025).