CAJ | 학술논문

针对陨石中铼锇同位素比值高精度测定，选取6块不同类型的普通球粒陨石（吉林陨石、信阳陨石、武安陨石、肇东陨石、河北陨石和荷叶塘陨石）和2块铁陨石（南丹铁陨石和未命名铁陨石T-5）进行预处理和化学过程的一些条件实验。实验结果表明，陨石金属表面的锈迹清洗使用1 mol/L的HCl效果更佳；对于样品溶解，逆王水溶解效果比浓硝酸好，高温溶样溶解彻底，常温状态下用逆王水仅能溶解出陨石样品中约30％的Os；微蒸馏二次纯化可提高Os测定信号的稳定性和精度；稀释剂的浓度及加入量应与样品匹配，且达到平衡状态是高精度和高准确度的保障；普通球粒陨石取样范围在0．1-0．3 g（即样品中Os的绝对含量为100 ng）即可获取最佳信号强度和精度；本次实验全流程空白Os可控制至0．5-81 pg，Re可控制至4-77 pg。采用同位素稀释法，187 Os/188 Os比值的精度最好可至4×10-6（ n＝120，2SE）。
침대운석중래철동위소비치고정도측정，선취6괴불동류형적보통구립운석（길림운석、신양운석、무안운석、조동운석、하북운석화하협당운석）화2괴철운석（남단철운석화미명명철운석T-5）진행예처리화화학과정적일사조건실험。실험결과표명，운석금속표면적수적청세사용1 mol/L적HCl효과경가；대우양품용해，역왕수용해효과비농초산호，고온용양용해철저，상온상태하용역왕수부능용해출운석양품중약30％적Os；미증류이차순화가제고Os측정신호적은정성화정도；희석제적농도급가입량응여양품필배，차체도평형상태시고정도화고준학도적보장；보통구립운석취양범위재0．1-0．3 g（즉양품중Os적절대함량위100 ng）즉가획취최가신호강도화정도；본차실험전류정공백Os가공제지0．5-81 pg，Re가공제지4-77 pg。채용동위소희석법，187 Os/188 Os비치적정도최호가지4×10-6（ n＝120，2SE）。
Some important conditions are discussed in this paper for the high-precision measurement of Re and Os in me-teorites by means of the isotope dilution technique .We have measured the Re-Os system in whole rock samples from six ordinary chondrites and two iron meteorites .The result shows that 1 mol/L HCl can be used to remove rust from a metal surface .Additionally , a high digestion temperature is necessary for the digestion of meteorites .Under normal conditions , only about 30%of the Os in the meteorite samples can be dissolved out .However , even though microdistillation is not necessary after Re-Os separation by means of distillation technique , this secondary purifica-tion method can improve the stability and accuracy of the signal .In contrast with samples dissolved by HNO 3 , the intensity of Os in samples dissolved by reverse aqua regia is far stronger .When the concentration and quantity of spikes are adequate and there is a perfect equilibrium between samples and spikes , we generally can attain good da-ta that are consistent with references .The minimum quantity of ordinary chondrites is 0.1 to 0.3 g or the absolute abundance of Os is 100 ng during digestion, with low blank levels (Re 4 to 77 pg, Os 0.5 pg to 2 ng) when the standard deviation of 187Os/188Os can be limited to ±4 ×10 -6(n=120, 2 SE).