membranes (Fumasep FKE and FKS membranes), C18 solid phase microextraction LC (C18 SPME) fiber, and styrene-divinylbenzene (XAD2) resin. These sorbents were considered candidates because of their relatively high surface area (meshes, porous materials), known high sorption properties for ionic chemicals (C18), and/or cation exchange properties. Additional information on the chemicals, materials and cleaning procedure can be found in the Supporting Information (SI, Section S1, Table and). Solvents were purchased from Fujifilm Wako Chemicals (Osaka, Japan) and were of GC or LC/MS grade. Formic acid, ammonium formate, both of LC-MS grade, were purchased from Fujifilm Wako Pure Chemical Corporation (Osaka, Japan). Ultrapure water of LC/MS grade (Fujifilm Wako Chemicals) or reverseosmosis-treated tap water further purified with an Ultrapure Water System (RFU665DA, Advantec, Tokyo, Japan) was used in the loading experiment. For the ecotoxicity tests, tap water dechlorinated with activated charcoal was employed as exposure medium. All glass materials used in this study were baked at 450 °C for 4 h.