Sep pak accell plus qma carbonate plus light cartridge

All radiosyntheses were carried out using anhydrous DMF (Aldrich) and MeOH (Aldrich or Acros). Cu(MeCN)₄OTf (Aldrich) was stored under argon. QMA cartridges (Sep-Pak Accell Plus QMA Carbonate Plus Light Cartridge) were obtained from Waters (Waters GmbH, Eschborn, Germany) and used without any preconditioning. RP-cartridges (Strata™-X 33 µm polymeric reversed phase, 200 mg/3 mL, tube) were from Phenomenex (Phenomenex Ltd., Aschaffenburg, Germany).
[¹⁸F]Fluoride was produced by the ¹⁸O(p,n)¹⁸F reaction by bombardment of enriched [¹⁸O]water with 16.5 MeV protons at the BC1710 cyclotron (The Japan Steel Works Ltd., Shinagawa, Japan) of the INM-5 (Forschungszentrum Jülich) or PETtrace 4 cyclotron (GE Healthcare, Uppsala, Sweden) at the IHB (Saint-Petersburg). If not otherwise noted, all radiolabeling experiments were carried out under ambient or synthetic air.
Standard deviations were calculated using standard formulae.

Aqueous [¹⁸F]fluoride (approx. 50 MBq, 0.6–2.0 GBq/mL) was passed through a strong anion exchange cartridge (Sep-Pak Accell Plus QMA Carbonate Plus Light cartridge, 46 mg, 40 μm, Waters) previously preconditioned with 10 mL of water. After most of the remaining water was removed with 20 mL of air, the cartridge was flushed with 10 mL of anhydrous acetonitrile (for DNA synthesis, max. 10 ppm H₂O, VWR) followed by 20 mL of air. Thereafter, [¹⁸F]fluoride was eluted from the QMA by means of a solution of [K⁺ ⊂ 2.2.2]OH⁻ cryptate in 500 μL of anhydrous acetonitrile. The cryptate was produced by dissolution of 34.3 mg Kryptofix® 222 (91 μmol, 1.1 eq., Sigma-Aldrich) and 83 μL of 1 M KOH (83 μmol, 1.0 eq., 99.99% semiconductor grade, Sigma Aldrich) in 1 ml of water and subsequent lyophilization. [K⁺ ⊂ 2.2.2]OH⁻-cryptate, produced by this way, could be stored at − 20 °C for several months. For optimization of the IE labeling on the laboratory scale, the following reaction parameters were varied and the incorporation of [¹⁸F]fluoride into the precursor was quantified by radio-thin layer chromatography (TLC) (Silica gel 60 RP-18 F254s coated aluminum sheets; 3:2 mixture (v/v) of MeCN in H₂O, supplemented with 10% of 2 M aqueous NaOAc solution and 1% of TFA).

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.