Gold and silver nanoparticle-assisted laser desorption ionization mass spectrometry compatible with secondary ion mass spectrometry for lipid analysis

To provide a convenient organic matrix-free spray-on sample preparation for laser desorption ionization (LDI) that is compatible with secondary ion mass spectrometry (SIMS) imaging mass spectrometry (IMS) techniques, silver and gold nanoparticles (NPs) were applied on a 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) lipid sample. Application of Ag and Au nanoparticles to the POPC sample allowed POPC lipid fragments to be detected using NP-LDI in both positive and negative polarities. In addition, the same sample prepared for NP-LDI experiments was used for C₆₀ SIMS lipid analysis, and a secondary ion signal enhancement was obtained for the [M+H]⁺ ion of the POPC lipid as well as for characteristics POPC lipid fragments in positive ion mode.