Ammonium tetrafluoroborate

All chemicals and solvents were used as received without further purification. Titanium foil (99.5%, 100 μm in thickness), copper foil (99.9%, 30 μm in thickness), and copper mesh were purchased from Nilaco Corporation. Iron(ii) chloride tetrahydrate (FeCl₂·4H₂O, 98%), ammonium tetrafluoroborate (NH₄BF₄, 97%), 4,4′-bipyridine, 2,2′:6′,2′′-terpyridine (98%), 1-iodohexane, bis(trifluoromethane) sulfonimide lithium salt (LiTFSI, 99.95%), and lithium metal were purchased from Sigma-Aldrich. The Li⁺-ion solid electrolyte was purchased from Ohara Corporation. Ethylene carbonate (EC, water content < 30 ppm) and dimethyl carbonate (DMC, water content < 30 ppm) were obtained from Kishida Chemicals. The polyvinylidene fluoride (PVDF) binder was obtained from MTI Corporation. N-Methyl-2-pyrrolidone (NMP) was obtained from J&K Chemicals. Super P carbon was obtained from TIMCAL.

Methanol, acetonitrile (HPLC grade) and ethanol (HPLC grade) were purchased from Rathburn Chemicals UK Ltd. All the reagents, ammonium tetrafluoroborate, anhydrous acetonitrile, and anhydrous methanol were purchased from Sigma Aldrich (UK). Sep-Pak Accell Plus QMA Carbonate Plus Light Cartridge (46 mg of sorbent per cartridge, 40 μm particle size), Sep-Pak alumina N Plus Light Cartridge, Oasis WAX Plus short cartridge (225 mg sorbent per cartridge, 60 μm particle size), and Sep-Pak Florisil Plus Light Cartridge were purchased from Waters UK. 0.9 % saline was purchased from Greater Glasgow & Clyde NHS Pharmacy Distribution Centre. All Sep-Pak cartridges were used without prior conditioning.
Boron trifluoride acetonitrile complex solution, 15.2–16.8% BF₃ basis; boron trifluoride-methanol solution, ~ 10% (~ 1.3 M), for GC derivatization; boron trifluoride dihydrate, 96% and aqueous ammonium hydroxide (25%) were purchased from Sigma-Aldrich. Precursors for [¹⁸F]TFB radiolabelling were diluted in an anhydrous solvent to the desired concentration as described in the "Results" and Discussion" sections. To obtain 1/500 dilution 3 µL of 10% boron trifluoride methanol solution was withdrawn from the original 10 mL shipment bottle by means of the 10 µL glass GC syringe and dissolved in 1500 µL of anhydrous acetonitrile in a sealed 2mL glass HPLC sample vial.