“…A critical piece in ambient ionization workflows is the ionization surface chosen for analyses. Previous studies have shown that a range of surfaces are suitable for the detection of metabolites, lipids, or drugs using DESI-MS: selected phospholipids (imprinted PARAFILM), 4 choline (PTFE-glass slides), 5 verapamil, sitamaquine, prazosin, and terfenadine (31ETF paper). 6 In these previous reports, investigators have tested a relatively narrow range of compounds for detection and targeted analysis (e.g., choline, verapamil, sitamaquine, etc.).…”