Application of silicon nanowires and indium tin oxide surfaces in desorption electrospray ionization.

Two nanostructured surfaces are introduced as advantageous substrates for desorption electrospray ionization mass spectrometry (DESI-MS). Nano-assisted laser desorption/ionization (NALDI) plates coated with silicon nanowires (SiNWs) and indium tin oxide (ITO) layers on glass are both conductive non-polar surfaces that were originally designed as superior substrates for matrix-free laser desorption/ionization. In this study, NALDI/SiNWs and ITO were tested as potentially useful DESI substrates for selected model analytes (cyclosporine, beauverolide, surfactin and nystatin). Both nanostructured surfaces produced more intense and longer-lasting signals than other tested surfaces (polytetrafluoroethylene, glass, polymethylmethacrylate and chromatography paper).