# EELS characterization of radiolytic products in frozen samples.
> 凍結試料における放射線分解生成物の電子エネルギー損失分光法による解析


## Abstract

Using electron energy loss spectroscopy (EELS), the radiation chemistry of cryogenically frozen aqueous specimens under electron beam irradiation was investigated by monitoring hydrogen and oxygen K-edges. In frozen 30% hydrogen peroxide solutions, molecular oxygen was detectable via a 531-eV O K-edge peak even at doses below 100 e/nm². Least-squares fitting of reference spectra indicated a molecular oxygen-to-water oxygen fraction of 0.03–0.05. Pure frozen water exhibited no discernible molecular oxygen or molecular hydrogen (K-edge near 13 eV) signals, even at doses exceeding 10⁵ e/nm². In contrast, frozen solutions containing sucrose or proteins displayed a molecular hydrogen peak near 13 eV at doses above 10⁵ e/nm², consistent with hydrogen bubble formation. Molecular oxygen was absent from all organic compound solutions tested, indicating that free radical decay in such systems preferentially yields molecular hydrogen rather than oxygen.

### Mechanism

Radiolytic decomposition under electron beam irradiation of frozen organic solutions (sucrose, protein) preferentially generates molecular hydrogen via free radical decay, while molecular oxygen production is negligible, contrasting with the behavior of frozen hydrogen peroxide solutions.

## Bibliographic

- **Authors**: Aronova MA, Sousa AA, Leapman RD
- **Journal**: Micron
- **Year**: 2011
- **PMID**: [21111626](https://pubmed.ncbi.nlm.nih.gov/21111626/)
- **DOI**: [10.1016/j.micron.2010.10.009](https://doi.org/10.1016/j.micron.2010.10.009)
- **PMC**: [PMC3023890](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3023890/)
- **Study type**: in vitro study
- **Delivery route**: in vitro
- **Effect reported**: not assessed

## Delivery context

This is basic research at the cellular or molecular level. For human application, inhalation is the most promising delivery route, but inhalation carries explosion risk and concentration matters (empirical LFL of 10%; high-concentration devices are not recommended).

## Safety notes

This is basic research at the cellular or molecular level. For human application, inhalation is the most promising delivery route, but inhalation carries explosion risk and concentration matters (empirical LFL of 10%; high-concentration devices are not recommended).

See also:
- [Inhalation concentration and LFL / UFL](https://h2-papers.org/en/safety-notes/inhalation-concentration)
- [Consumer Affairs Agency accident cases](https://h2-papers.org/en/safety-notes/accident-cases)
- [Inhalation safety threshold lineage](https://h2-papers.org/en/safety-notes/lineage)

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> **Cite as**: H2 Papers — PMID 21111626. https://h2-papers.org/en/papers/21111626
> **Source**: PubMed PMID [21111626](https://pubmed.ncbi.nlm.nih.gov/21111626/)