炭素-14測定のために合成したベンゼン中の不純物とそれらの放射能測定への影響 [in Japanese] Impurities in Benzene Synthesized for ^<14>C Measurement and Their Influence on Activity Evaluation [in Japanese]
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Impurities were analyzed in the benzene synthesized from an environmental sample for <sup>14</sup>C measurement and influence of the impurities on <sup>14</sup>C activity measurement was examined. Chloride, nitrite, nitrate, phosphate, sulfate ions were observed in the benzene. Contamination of inner glass surface of the synthesis line, especially traps, was found to be a source for these impurities. Toluene, ethyl benzene, <i>o</i>-xylene and grease which was used for connections and cocks in the line were detected. The amount of benzene-derivatives was small and did not act as quenchers in <sup>14</sup>C measurement. On the other hand, a large amount of grease (DOW CORNING HIGH VACUUM SILICONE GREASE) was observed in the synthesized benzene, resulting in underestimation of <sup>14</sup>C activity. Alternative grease (Shin-Etsu Co., Ltd.; FG-721) is insoluble to benzene. <sup>14</sup>C concentration of NBS RM49 showed in good agreement with the recommended value when FG-721 was used, suggesting a suitability for the benzene synthesis.
- Jpn. J. Health Phys.
Jpn. J. Health Phys. 33(1), 17-24, 1998-03
Japan Health Physics Society