1P-06 PDF
Application of time-of-flight secondary ion mass spectrometry into peptide analysis
Although amino acid sequences can be determined by other techniques such as CID-MS/MS, ToF-SIMS provides important further information, which are rarely obtained from other analytical methods, such as surface structures of large peptides or proteins and molecular images. For imaging larger peptides or proteins, fragment ions specific to a target molecule are essential when molecular ions are not strongly detected or a sample contains other similar molecules. We have found that the energy range approximately 5 ≤ E/n ≤ 333 eV/atom is useful for peptide analysis based on peptide fragments and [M+H] ions, especially the best E/n is between 6 to 10 eV/atom. The findings from this study would be applicable to interpretation of proteins that are too large to be detected as [M+H]+ using ToF-SIMS. Specific fragment ions are useful for protein or peptide imaging in tissues in the future.