Sep pak accell plus qma cartridge

Chemicals: Glu-urea-Lys (Ahx)-HBED-CC (PSMA-11) was purchased from ABX (Radeberg, Germany). AlCl₃.6H₂O, sodium acetate trihydrate and acetic acid were all metal free. Sodium phosphate, ethanol, water, acetonitrile and trifluoroacetic acid (TFA) were of high-grade purity. Sep-Pak Accell Plus QMA cartridge were from Waters. ¹⁸F was obtained in a PETtrace cyclotron (16.5 MeV, GE Healthcare) using a 2.5 mL Niobium target via ¹⁸O (p,n) ¹⁸F reaction. Preparation of ¹⁸F–fluoride: QMA cartridge was conditioned with 5 mL of 0,5 M sodium acetate, followed by 10 mL of water (Milli Q, 18,5 MΩ). Activity measurements were performed with a dose calibrator Capintec CRC 25R, CRC 25 PET or a 3”× 3” well type NaI(Tl) solid scintillation detector coupled to a multichannel analyzer ORTEC.
Preparation of solution: Sodium acetate/acetic acid buffer 0,5 M and 0,05 M (pH 4,5) were prepared from each component and mixing them to obtain the desired final pH. PSMA-11 was dissolved in water (2 mg/mL) and aliquots were frozen stored (− 18 °C). AlCl₃.6H₂O 0,01 M was prepared in 0,05 M acetate buffer (pH 4) and stored at 4 °C.

0.5–1.5 GBq of aqueous [¹⁸F]fluoride ion was trapped in an anion-exchange resin cartridge (Sep-Pak Accell Plus QMA cartridge, WAT023525, Waters) pre-activated with 10 mL 1 N NaHCO₃ (aq), 10 mL water (H₂O) followed by 10 mL air. The trapped [¹⁸F]fluoride ion was released with solution A, composed of 25.5 μmol Kryptofix (K₂₂₂) and 4.5 μmol KHCO₃ in acetonitrile (MeCN):H₂O (85:15, 1 mL) or solution B, composed of 19.55 μmol K₂₂₂ and 0.9 μmol K₂CO₃ in MeCN:H₂O (85:15, 1 mL). The solvent was removed by heating at 90 °C under a stream of N₂ and fluoride ion was dried by azeotropic distillation with MeCN (2 × 0.5 mL). Compound 1 (5 mg) was dissolved in anhydrous dimethyl sulfoxide (DMSO, 100–500 μL) and the obtained solution was added to the dried [¹⁸F]fluoride ion/K₂₂₂/K₂CO₃ mixture. The vial was then sealed and stirred at 110–180 °C for 15–30 min, quenched with H₂O and analysed by radioTLC.