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 ∼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 β-casein followed by titania NTA SALDI MS analysis. The detection limit for small organics and peptides is in low fmol.