Etoh nh4oh

16 nmol of Cy5-B was dissolved in 20 μL of tetrahydrofuran (THF). A 20-μL HF solution (0.6 M in water) containing 100 mCi of ¹⁸F⁻ ion was added. After 1 h of incubation at 50 °C, the mixed solution was quenched with EtOH/NH₄OH (95/5, v/v, Sigma, St. Louis, MO, USA) and purified with over a plug of 200 mesh silica gel according to our previous protocol for purifying the boronate-based ¹⁸F labeling [22 (link),23 (link),24 (link),34 (link)]. The mixed solution was loaded into a 10-mL volume syringe that was filled with 5 mL 200 mesh silica gel. Cotton was filled at the outlet before filling with silica gel to avoid silica gel leakage. The radiotracer was collected with EtOH/NH₄OH (95/5, v/v, Sigma) as the eluent. The excessive ¹⁸F was retained in the silica gel. The collected radioactive, fluorescent, blue fraction was dried for 15 min with nitrogen, and then re-dissolved in 1× PBS buffer (pH 7.4) for intravenous (i.v.) tail vein injection.