Investigation of Surface Morphology on Ion Desorption in SALDI-MS on Tailored Silicon Nanopillar Arrays

The surface morphology of the substrate is one of the decisive factors for ion-desorption efficiency in surface-assisted laser desorption/ionization mass spectrometry (SALDI-MS). Understanding the impacts on the surface morphology of the substrate during laser desorption/ionization is the premise for improving the performance of SALDI-MS. In this study, the correlations of ion-desorption efficiency and internal energy transfer with surface morphology, including the total surface area, optical absorption, and surface voidage, were systematically investigated on the basis of ordered silicon nanopillar arrays (NAPAs). The results suggest that the SALDI-MS substrate has enough optical absorption for effective ion desorption by enhancing internal energy transfer and promoting the restructuring of the silicon surface; the high surface voidage of NAPAs can increase the ion-desorption intensity because it can increase the temperature of the substrate surface. This work reveals that with enough optical absorption, high surface voidage is vital for the design of a SALDI-MS substrate based on silicon.