MAT 253气体同位素质谱仪测定微量氢同位素组成进样方法初探
An Improved Sampling Method for Measurement of Trace Hydrogen Isotopic Composition by MAT 253 Gas Isotope Mass Spectrometer
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摘要: 幔源流体活动区天然气中微量H2是研究幔源H2同位素组成的最佳样品,但受目前测试技术的限制,能准确测试同位素组成的H2浓度下限仍然有待继续降低。前人研究表明,当H2浓度低于1.5%时,测试结果的误差较大,可信度较低,这可能与载气进样时在进样针孔附近发生了随机分馏有关。为了避免这种随机分馏,本文提出了一种利用压差进样的方法,即利用饱和食盐水增加样品瓶内的压力实现进样。实验结果表明,利用这种进样方法,不同浓度条件下,H2同位素组成测试值的极差与标准偏差都随H2浓度的增加而减小,统计得到的绝对误差与仪器的误差范围相当。因此,该进样方法可以有效避免微量H2在进样过程中发生的随机分馏,提高测试结果的精度和可信度。同时表明可以对现有设备进行合理改造,挖掘仪器的测试潜能。Abstract: The trace hydrogen in the natural gas from the mantle-derived fluid areas is the best specimen to reveal the isotopic composition characters of mantle-derived fluids. Restricted by the present measurement methods, the detection limit of hydrogen for accurate measurements of hydrogen isotopic composition should be further improved. It was proved that the measurement error of hydrogen isotopes was relatively larger and reliability of the measurement results deteriorated when the hydrogen content was lower than 1.5%, which may relate to the random fractionation of hydrogen isotopes around the inlet needle when it was sampled by the carrier gas. In order to avoid this random fractionation, an improved pressure sampling method was brought out, that is, increasing the pressure inside the sample container by pumping in salt-saturated water. The experiment results showed that by this sampling method the range and the standard deviation of the measured hydrogen isotope values declined with the increasing of the hydrogen content within 1% range and the absolute error was equivalent to that of the system error of MAT 253 instrument. Thus, this sampling method could effectively avoid the random fractionation of hydrogen isotopes during the sampling and improve the accuracy and reliability of the measurement results. It was also proved that the presently employed machine could be reasonably improved in order to enhance its function.
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陶明信,徐永昌,韩文功,高波,马锦龙,王万春.中国东部幔源流体的活动特征与成藏效应[J].大地构造与成矿学,2001,25(3):265-270. 陶明信,徐永昌,史宝光,蒋中惕,沈平,李晓斌,孙明良.中国不同类型断裂带的地幔脱气与深部地质构造特征[J].中国科学:D辑,2005, 35 (5): 441-451. 徐永昌,沈平,孙明良,徐胜.我国东部非烃及稀有气体地球化学[J].中国科学:B辑,1990,20(6):645-651. 金之钧,杨雷,曾溅辉,张刘平.东营凹陷深部流体活动及其生烃效应初探[J].石油勘探与开发, 2002,29(2):42-44. 金之钧,张刘平,杨雷,胡文暄.沉积盆地深部流体的地球化学特征及油气成藏效应初探[J].地球科学,2002,27(6):659-665. Jin Z J, Zhang L P, Yang L, Hu W X. A preliminary study of mantle-derived fluids and their effects on oil/gas generation in sedimentary basins [J]. Journal of Petroleum Science and Engineering, 2004,41:45-55. Jin Z J, Zhang L P, Yang L, Hu W X. A preliminary study of mantle-derived fluids and their effects on oil/gas generation in sedimentary basins [J]. Journal of Petroleum Science and Engineering, 2004,41:45-55.
杨雷.沉积盆地深部流体活动特征及加氢生烃效应 .北京:中国石油大学,2002. 曾溅辉,金之钧,张刘平.东营凹陷高青—平南断裂带幔源流体活动特征及其成藏效应[J].地质论评,2004,50(5):501-506. Meng Q Q, Wu J F, Zhang L P. A study on the ore-forming effect of mantle-derived fluid[J]. Petroleum Science,2007,4(4):44-49. Meng Q Q, Wu J F, Zhang L P. A study on the ore-forming effect of mantle-derived fluid[J]. Petroleum Science,2007,4(4):44-49.
刘国勇,张刘平,杨振平.天然气中氢气的地球化学特征及油气成藏效应[J].天然气工业, 2004,24(11):31-33. Itsuro Kita, Sadao Matsuo, Hiroshi Wakita, Yasukazu Nakamura. D/H ratios of H2 in soil gases and an indicator of fault movements[J]. Geochemical Journal, 1980,14:317-320. Itsuro Kita, Sadao Matsuo, Hiroshi Wakita, Yasukazu Nakamura. D/H ratios of H2 in soil gases and an indicator of fault movements[J]. Geochemical Journal, 1980,14:317-320.
Javoy M, Pineau F. The volatile record of "popping" rock from the Mid-Atlantic Ridge at 14°N: Chemical and isotopic composition of gas trapped in the vesicles[J]. Earth Planet Science Letter,1991,107:598-611. Javoy M, Pineau F. The volatile record of "popping" rock from the Mid-Atlantic Ridge at 14°N: Chemical and isotopic composition of gas trapped in the vesicles[J]. Earth Planet Science Letter,1991,107:598-611.
Delany J R, Muenow D W, Graham D G. Abundance and distribution of water, carbon and sulfur in the glassy rims of submarine pillow basalts [J]. Geochim et Cosmochim Acta,1978,42:581-594. Delany J R, Muenow D W, Graham D G. Abundance and distribution of water, carbon and sulfur in the glassy rims of submarine pillow basalts [J]. Geochim et Cosmochim Acta,1978,42:581-594.
上官志冠,霍卫国.腾冲热海地热区逸出H2的δDH2值及其成因[J].科学通报,2001,46(15):1316-1320. Shangguan Z G, Huo W G. δD values of escaped H2 from hot springs at the Tengchong Rehai geothermal area and its origin[J]. Chinese Science Bulletin,2002,47(2):146-149. Shangguan Z G, Huo W G. δD values of escaped H2 from hot springs at the Tengchong Rehai geothermal area and its origin[J]. Chinese Science Bulletin,2002,47(2):146-149.
上官志冠,白春华,孙明良.腾冲热海地区现代幔源岩浆气体释放特征[J].中国科学:D辑,2000,30(4):407-414. 上官志冠.腾冲火山区幔源岩浆气体上升过程中的变化及原因[J].地质论评,1999,45(增刊):926-933. 上官志冠,赵慈平,李恒忠,高清武,孙明良.腾冲热海火山地热区近期水热爆炸的阶段性演化特征[J].矿物岩石地球化学通报,2004,23(2):124-128. Mark Henning, Dariusz Strapoc, Grzegorz P Lis, Peter Sauer, Jon Fong, Arndt Schimmelmann, Lisa M Pratt. Versatile inlet system for on-line compound-specific δD and δ13C gas chromatography-oxidation/reduction-isotope ratio mass spectrometry analysis of gaseous mixtures[J]. Rapid Communication s in Mass Spectrometry, 2007,21:2269-2272. Mark Henning, Dariusz Strapoc, Grzegorz P Lis, Peter Sauer, Jon Fong, Arndt Schimmelmann, Lisa M Pratt. Versatile inlet system for on-line compound-specific δD and δ13C gas chromatography-oxidation/reduction-isotope ratio mass spectrometry analysis of gaseous mixtures[J]. Rapid Communication s in Mass Spectrometry, 2007,21:2269-2272.
武汉大学.分析化学[M]. 4版.北京:高等教育出版社,2000:8-13.
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