Sulfur species in volcanic gases.
Sulfur species in volcanic gases.
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火山气体中的硫物质。
DOI：
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发表时间：
2001
影响因子：
7.4
通讯作者：
Kristin Garofalo
中科院分区：
文献类型：
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作者：
G. Montegrossi;F. Tassi;O. Vaselli;and Antonella Buccianti;Kristin Garofalo
通过对现有方法的修正、更新和改进，提出了一种测定火山气体中硫化物（SO2、H2S、S8(0)）的新方法。该方法最显著的优点可以简单概括如下：(i)在气体取样过程中，使用预先抽真空的带有纯化的0.15M Cd(OH)2的钍头小瓶，在4 M NaOH中进行取样时，硫种之间的反应停止，有利于H2S作为Cd的沉淀；（ii）所有硫种（SO2、H2S、S8(0)）均转化为SO4后，采用离子色谱法进行分析，相对于以往的研究，检测限明显降低；（iii）中间步骤的适当等价物可用于确定火山气体中常见的其他物质，如CO2、HCI、HF、HBr、HI等；（iv）所提出的方法不会影响所有其他气体种类的测定，即，一个小瓶可以用于分析除NH3外的火山气体的全部化学成分。根据意大利南部伊奥利亚群岛（Aeolian Islands, southern Italy） Vulcano岛F5火山口喷气孔气体采样数据计算的统计参数表明，s的均值标准误差（s/根n）较高（0.10），其次是SO2、H2S和CO2（分别为0.04、0.038和0.028）。SO2表现出较高的变异系数（12.1%），其次是H2S、S和CO2（分别为5.7、1.5和0.8%）。此外，如果考虑到采样的时间依赖性，则测量值不是随机波动，而是倾向于遵循系统模式，不受统计控制，这可能表明火山系统的一种自然波动。来自不同地球动力学区（美国夏威夷、墨西哥埃尔奇洪、哥斯达黎加波阿斯）火山系统的其他火山口喷气孔也进行了分析。
A new analytical method for the determination of the sulfur species (SO2, H2S, S8(0)) in volcanic gases is proposed by revising, updating, and improving previous methods. The most significant advantages of the proposed procedure can briefly be summarized, as follows: (i) the reaction among sulfur species stops during the gas sampling by using preevacuated thorion-tapped vials with purified 0.15M Cd(OH)2 in 4 M NaOH to favor the precipitation of H2S as CdS; (ii) all the sulfur species (SO2, H2S, S8(0)) are analyzed by ion chromatography, after conversion to SO4, which allows the detection limit to be lowered significantly with respect to the previous studies; (iii) appropriate aliquots from intermediate steps may be used to determine other species commonly present in volcanic gases such as CO2, HCI, HF, HBr, HI, and so forth; (iv) determination of all the other gas species is not jeopardized by the proposed method, i.e., one single vial can be used for analyzing the full chemical composition of a volcanic gas with the exception of NH3. Statistical parameters calculated from gas sampling data at the F5 crater fumarole in Vulcano Island (Aeolian Islands, southern Italy), suggest that the standard error of mean (s/ root n) is higher for S (0.10), followed by SO2, H2S, and CO2 (0.04, 0.038, and 0.028, respectively). SO2 shows the higher variation coefficient (12.1%) followed by H2S, S, and CO2 (5.7, 1.5, and 0.8%, respectively). Furthermore, if the time dependence of sampling is taken into account, the measured values, instead of fluctuating in a random manner, tend to follow systematic patterns, out of statistical control, possibly suggesting a sort of natural fluctuation of the volcanic system. Other crater fumaroles from volcanic systems located in different geodynamical areas (Hawaii, USA, El Chichon, Mexico, Poas, Costa Rica) have been analyzed as well.