@misc{oai:repo.qst.go.jp:00075020,
 author = {Makino, Yusuke and Fukui, Koji and C. Krishna, Murali and Nakanishi, Ikuo and Ken-ichiro, Matsumoto and Makino, Yusuke and Nakanishi, Ikuo and Matsumoto, Kenichiro},
 month = {Apr},
 note = {Background
For performing a quantitative EPR measurement, an external and/or internal standard sample having a known spin concentration is required. If adequate reproducibility of the sample volume, shape, and positioning in the cavity for every EPR measurement can be guaranteed, the external standard and the sample tested can be directly compared and then the process of comparisons for quantification can be simplified.

Methods
0.1 mM TEMPOL sample as a standard sample loaded into the capillary was measured with a X-band EPR (JEOL, Tokyo, Japan). 
Reproducibilities of EPR signal intensity of the 0.1 mM TEMPOL standard were estimated for three different types of sample tubes; a PTFE tubing, a glass capillary, and a quartz flat cuvette. A special silicon cap was put on the top of the sample holder to fix the glass capillary. Again, the reproducibility was tested with or without the silicon cap.

Results
The cuvette could show the most suitable reproducibility among the three sample tubes. Reproducibility and sensitivity of the EPR signal intensity was improved when the standard sample in a capillary was measured using the silicon cap equipment.

Conclusion
Suppressing the sample movement could improve reproducibility and sensitivity of the EPR spectroscopy. For a quantitative EPR measurement, retaining the volume and position of the sample in the cavity is quite important., 9th Biennial Meeting for the Society for Free Radical Research Asia},
 title = {Suitable Sample Tube for Quantitative Measurement Using X-band EPR},
 year = {2019}
}