Figure 2: Schematic of microdroplet-based radiosynthesis process.

(a) A fixed volume of [¹⁸F]fluoride/base stock solution is added to the chip. (b) Additional [¹⁸F]fluoride/[¹⁸O]water (without base) is added to the chip to scale the amount of radioactivity. (c-d) The solvent is evaporated, leaving a dried residue. (e) MeCN is added. (f-g) Azeotropic distillation is performed to remove residual water and leave a dried residue of the [¹⁸F]fluoride/base complex. (h) A fixed volume of the precursor stock solution is added, and the chip is covered (i-j). (k) The chip is heated to perform the reaction. (l) The chip is separated, and MeOH is added (m) to dilute the crude product. (n) The diluted product is removed from the chip. Steps m-n are repeated for the cover chip as well.