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.
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.