Laser Desorption/Ionization on Au@TiO Core@Shell Nanostars for Mass Spectrometric Analysis of Small Molecules.

The core@shell nanostars composed of star-like Au nanocores with TiO shells (Au@TiO NSs) are synthesized in a one-pot reaction without any reducing or surface-controlling agents. The Au@TiO NSs exhibit strong absorption in the UV region based on the interaction between the Au nanocore and the TiO shell, and this optochemical property leads to the efficient laser desorption/ionization time-of-flight mass spectrometry (LDI-TOF-MS) analysis of small molecules with low background interference and high reproducible mass signals compared with spherical Au nanoparticles (NPs). The limit of detection and dynamic range values of various analytes also improved with Au@TiO NSs compared with those obtained with spherical Au NPs. Our findings successfully demonstrate that Au@TiO NSs are a promising matrix for the LDI-TOF-MS analysis of various small molecules as well as synthetic polymers.