セリウム内標準法を用いた機器中性子放射化分析法によるヒト血清中のセレンと亜鉛の定量 [in Japanese] Determination of selenium and zinc in human serum by instrumental neutron activation analysis with a cerium internal standard. [in Japanese]
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がん診断前に採血された血清試料について,セレン及び亜鉛濃度と,その後の発がんリスクとの関連を疫学的に明らかにするため,セリウムを内標準とする機器中性子放射化分析法(INAA)による,少量(0.2ml以下)のヒト血清中のセレンと亜鉛の同時定量法を確立した.方法の概要は以下のとおりである.一定量のセリウム標準溶液を添加した血清試料と比較標準溶液を合成石英管にとり,試料は凍結乾燥後減圧封人し,比較標準はそのまま減圧封人し,JRR-2(熱中性子束2.2×10<SUP>13</SUP>n cm<SUP>-2</SUP>s<SUP>-1</SUP>以上)で265.5時間照射をする.約1か月間冷却後,石英管表面をフッ化水素酸で約5μmエッチングし,Ge(Li)検出器で一定時間(4000秒以下)γ線スペクトルを測定する.試料及び比較標準試料の<SUP>141</SUP>Ceに対する<SUP>75</SUP>Seと<SUP>65</SUP>ZRのγ線ピーク面積比から試料中のセレン及び亜鉛含量を算出する.同一試料14個による定量値のRSDは3.0%(Se)及び5.2%(Zn)であった.本法による血清試料及びNISTBovinc Liver標準試料(SRM1577,SRMI577a)の定量値は,NISTの保証値を含む他の方法による定量値と,極めてよく一致することが確認された.
An instrumental neutron activation analysis (INAA) method for simultaneously determining the Se and Zn concentrations in serum specimen was developed in order to study and clarify the associations between prediagnostic serum Se and Zn, and the subsequent risk of lung and stomach cancer in which the amount of available sera was quite limited. Cerium was used as an internal standard in order to maintain the accuracy and precision, even with less than 0.2 ml of a sample and short measuring time. Samples, (0.10.2 ml), and Se-Zn standard solutions were mixed with exact amounts of the Ce standard solution, respectively. After lyophilization, the samples were sealed in a high-purity quartz tube. The Se-Zn standard solutions were also sealed in a quartz tube without lyophilization. The samples and standards were irradiated in the JRR-2 with a thermal neutron flux of more than 2.2 × 10<SUP>13</SUP> n cm<SUP>-2</SUP> s<SUP>-1</SUP> for 265.5 hours. After cooling for one month, about 5 μm surface layers of the quartz ampule for the samples and standards were etched with hydrofluoric acid; γ-ray spectra were then measured with a Ge(Li) detector. The contents of Sc and Zn were obtained from the peak area of γ-rays of 145, 265 and 1115 keV for <SUP>141</SUP>Ce, <SUP>75</SUP>Se and <SUP>65</SUP>Zn, respectively. The relative standard deviations of the analytical results among the 14 independent samples were 3.0 and 5.0% for Se and Zn, respectively. The accuracy of the present method was confirmed by the satisfactory agreement between the results obtained by the present method and those obtained by other methods, including the certified values of NIST Standard Reference Materials of Bovine Liver (SRM1577, SRM1577a).
- Bunseki kagaku
Bunseki kagaku 41(11), 581-587, 1992-11-05
The Japan Society for Analytical Chemistry