Arakawa Masashi, Yamamoto Junji, Kagi Hiroyuki
Geochemical Laboratory, Graduate School of Science, The University of Tokyo, Tokyo 113-0033, Japan.
Appl Spectrosc. 2007 Jul;61(7):701-5. doi: 10.1366/000370207781393244.
We investigated the applicability of micro-Raman spectroscopy for determining carbon isotopic compositions (13C/12C) of minute CO2 fluid inclusions in minerals. This method is nondestructive and has sufficiently high spatial resolution (1 microm) to measure each fluid inclusion independently. Raman spectra of CO2 fluid have 12CO2-origin peaks at about 1285 cm(-1) and 1389 cm(-1) (V(-)([12]) and V+[12]) and a 13CO2-origin peak at about 1370 cm(-1) (V+[13]). The relationship between carbon isotopic compositions and peak intensity ratios of V+[12] and V+[13] was calibrated. Considering several factors affecting the peak intensity ratio, the error in obtained carbon isotopic composition was 2% (20%). The reproducibility of the intensity ratio under the same experimental environment was 0.5% (5%). Within these error values, we can distinguish biogenic CO2 from abiogenic CO2.
我们研究了显微拉曼光谱法在测定矿物中微小二氧化碳流体包裹体碳同位素组成（13C/12C）方面的适用性。该方法无损，且具有足够高的空间分辨率（1微米），能够独立测量每个流体包裹体。二氧化碳流体的拉曼光谱在约1285厘米（-1）和1389厘米（-1）处有12CO2来源的峰（V（-）[12]和V + [12]），在约1370厘米（-1）处有13CO2来源的峰（V + [13]）。对碳同位素组成与V + [12]和V + [13]的峰强度比之间的关系进行了校准。考虑到影响峰强度比的几个因素，所获得的碳同位素组成的误差为2%（20‰）。在相同实验环境下，强度比的重现性为0.5%（5‰）。在这些误差值范围内，我们能够区分生物成因二氧化碳和非生物成因二氧化碳。
