Nanofilament silicon for matrix-free laser desorption/ionization mass spectrometry

Mass spectrometry (MS) provides quantitative information toward accurate mass identification of unknown molecules and has become a powerful and widely used technique for bioanalysis. In this chapter, we describe the fabrication and MS analysis steps for a high sensitivity matrix-free laser desorption/ionization mass spectrometry (LDI-MS) target substrate termed nanofilament silicon (nSi). Unlike other nanostructured porous silicon surfaces, nSi possesses an open pore morphology with associated benefits including efficient transport of sample into the nanopores and effective removal of solvent from the surface. The utility of nSi targets for LDI-MS analysis lies primarily in the analysis of small molecules, which are typically less than 5,000 Da with a detection sensitivity in the attomole range.