Ion chromatography was performed using an IC-8100EX (TOSOH, Tokyo, Japan) and using a TSKgel SuperIC-Anion HR column (4.6 × 150 mm, TOSOH, Tokyo, Japan) with a TSKgel guardcolumn SuperIC-A HS guard column (4.6 × 10 mm, TOSOH, Tokyo, Japan). The analysis was run using an eluent of 2.7 mM sodium carbonate and 2.2 mM sodium hydrogen carbonate using milli-Q water. A flow rate was 1.00 mL/min, giving the following retention times: fluoride = 3.6-3.7 min. Milli-Q water was used as the calibration blank. LC-MS measurements were performed using an LCMS-2050 (SHIMADZU, Kyoto, Japan) and using a Shimpack XR-ODSII column (2.0 × 100 mm, SHIMADZU, Kyoto, Japan). A 20 mM aquated ammonium acetate: methanol gradient mobile phase at a flow rate of 0.25 mL/min was used for separation. Before ion chromatography and LC-MS measurements, liquid samples were filtered through a 0.22 μm nylon syringe filter (Membrane Solutions Ltd., Auburn, WA, USA).