Surface-assisted laser desorption/ionization mass spectrometry on titania nanotube arrays.

Titania nanotube arrays (NTA) generated from anodizing processes are tested as the substrate for surface-assisted laser desorption/ionization mass spectrometry (SALDI MS). The background generated from titania NTA is very low, making the approach suitable for the analysis of small molecules. The upper detectable mass is approximately 29 kDa. Homogeneous sample deposition leads to good shot-to-shot reproducibility and suitability for quantitative analysis. Additionally, phosphopeptides can be selectively trapped on the titania NTA substrate, as illustrated by simply depositing a tryptic digest of beta-casein followed by titania NTA SALDI MS analysis. The detection limit for small organics and peptides is in low fmol.