Abstract
Time-of-flight secondary ion mass spectrometry (TOF-SIMS) is a powerful tool to reveal the chemical distribution in many materials. We have applied TOF-SIMS to investigate the distribution of organic biomolecules and inorganic metals in plants. The positional, temporal, and quantitative information of water-soluble chemicals in a living state are essential information to elucidate many biological mechanisms. However, traditional quantification of water-soluble chemicals such as coniferin and sucrose depends on a bulk-analysis providing an approximate position of them. To analyze the position and quantity of the water-soluble chemicals in more detail, we developed the cryo-TOF-SIMS/SEM system. The system consists of a glove box, a cryo-SEM, and a cryo-TOF-SIMS, which were interconnected by a cryo-vacuum shuttle. By using the system, successive TOF-SIMS measurements and SEM observations are possible for the frozen-hydrated samples. We applied the system to freeze-fixed Ginkgo biloba and estimated the distribution of water-soluble chemicals: coniferin and sucrose. The quantity of coniferin and sucrose were evaluated by HPLC and ion chromatography, respectively. As a result of cryo-TOF-SIMS/SEM analysis, the secondary ion derived from coniferin and sucrose was unevenly distributed in phloem, tracheids, or ray cells.
