For the acquisition of liquid metal ion gun (LMIG) ToF-SIMS spectra of the lipid nanoparticle formulation, a 30 keV Bi3 + primary beam was used. LMIG current was 0.03 pA. The acquisition was run on the area of 500 µm × 500 µm using random raster mode. Optimal target potential was set to +58 V. The total ion dose per measurement was 7.36 × 10 9 . The analysis was carried out at -170°C using a closed-loop liquid nitrogen pumping system (IONTOF GmbH).