Automated concentration of [18F]fluoride into microliter volumes

Concentration of [F-18]fluoride has been mentioned in literature, however, reports have lacked details about system designs, operation, and performance. Here, we describe in detail a compact, fast, fully-automated concentration system based on a micro-sized strong anion exchange cartridge. The concentration of radionuclides enables scaled-up microfluidic synthesis. Our system can also be used to provide highly concentrated [F-18]fluoride with minimal water content. We demonstrate how the concentrator can produce varying concentrations of [F-18]fluoride for the macroscale synthesis of N-boc-5-[F-18]fluoroindole without an azeotropic drying process, while enabling high starting radioactivity. By appropriate choice of solid-phase resin, flow conditions, and eluent solution, we believe this approach can be extended beyond [F-18]fluoride to other radionuclides.