A novel application of time-of-flight secondary ion mass spectrometry (ToF-SIMS) with continuous Ar cluster beams to peptide analysis was investigated. In order to evaluate peptide structures, it is necessary to detect fragment ions related to multiple neighbouring amino acid residues. It is, however, difficult to detect these using conventional ToF-SIMS primary ion beams such as Bi cluster beams. Recently, C60 and Ar cluster ion beams have been introduced to ToF-SIMS as primary ion beams and are expected to generate larger secondary ions than conventional ones. In this study, two sets of model peptides have been studied: (des-Tyr)-Leu-enkephalin and (des-Tyr)-Met-enkephalin (molecular weights are approximately 400 Da), and [Asn1 Val5]-angiotensin II and [Val5]-angiotensin I (molecular weights are approximately 1,000 Da) in order to evaluate the usefulness of the large cluster ion beams for peptide structural analysis. As a result, by using the Ar cluster beams, peptide molecular ions and large fragment ions, which are not easily detected using conventional ToF-SIMS primary ion beams such as Bi3+, are clearly detected. Since the large fragment ions indicating amino acid sequences of the peptides are detected by the large cluster beams, it is suggested that the Ar cluster and C60 ion beams are useful for peptide structural analysis.
Continuous Ar cluster beam ToF-SIMS Peptide structure (des-Tyr)-enkephalin Angiotensin
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The authors thank Messrs Rowland Hill and Retsu Oiwa for their useful support.
Urquhart AJ, Taylor M, Anderson DG, Langer R, Davies MC, Alexander MR (2008) Analytical Chemistry 80:135–142CrossRefGoogle Scholar
Leufgen K, Mutter M, Vogel H, Szymczak W (2003) Journal of the American Chemical Society 125:8911–8915CrossRefGoogle Scholar