| AVS 58th Annual International Symposium and Exhibition | |
| Applied Surface Science Division | Tuesday Sessions |
| Session AS-TuM |
| Session: | Imaging and 3D Chemical Analysis |
| Presenter: | Jiro Matsuo, QSEC, Kyoto University, CREST, Japan |
| Authors: | J. Matsuo, QSEC, Kyoto University, CREST, Japan K. Ichiki, Kyoto University, Japan T. Yamanobe, Kyoto University, Japan Y. Yamamoto, Kyoto University, Japan S. Ibuki, QSEC, Kyoto University, CREST, Japan T. Aoki, Kyoto Univeristy, CREST, Japan T. Seki, Kyoto Univeristy, CREST, Japan |
| Correspondent: | Click to Email |
The field of secondary ion mass spectrometry (SIMS) for biological material analysis is receiving much attention nowadays, because molecular, structural and chemical information is considered to be invaluable. However, for large biomolecules the sensitivity of SIMS needs to be improved. Cluster ion beams have been reported to enhance the yields of secondary ions, because of the high-density energy deposition and multiple collisions near surfaces. SF5, C60, Au3 and Bi3 were found to be quite useful for SIMS of organic materials.
We have proposed using a large Ar cluster beam for organic SIMS. This beam has a number of advantages over other cluster beams for molecular depth profiling of various polymers, and it provides new opportunities for sputtering molecules without inducing significant damage [1]. Biomolecules are also very fragile and thus difficult to sputter with conventional ion beams; therefore, a large Ar cluster beam would be quite suitable for biological material analysis. However, molecular imaging requires a focused Ar cluster beam, and we developed a new Ar cluster ion gun aiming to obtain a fine-focused beam of several mm diameter. An orthogonal acceleration time-of-flight (oa-TOF) mass spectrometer, which allows the use of a continuous beam, was also combined in the system, and a mass resolution higher than 6000 was obtained. Because there was no need to use the ion-bunching technique in this system, there was no tradeoff between beam diameter and mass resolution. This is another advantage of this molecular imaging system over the conventional TOF instrument. This novel system is quite useful for both molecular depth profiling and imaging.
The latest results of this system and its performance in molecular imaging of cells and tissues will be presented and discussed.
[1] J. Matsuo, S. Ninomiya, H. Yamada, K. Ichiki, Y. Wakamatsu, M. Hada, T. Seki and T. Aoki, Surf. Interface Anal. (2011) 42, 1612