Institute for Inorganic and Analytical Chemistry, Johannes Gutenberg-Universität Mainz, Duesbergweg 10-14, 55099 Mainz, Germany.
Anal Bioanal Chem. 2012 Apr;402(10):3345-57. doi: 10.1007/s00216-011-5658-z. Epub 2012 Jan 8.
Knowledge of the composition and emission rates of iodine-containing volatiles from major widespread seaweed species is important for modeling the impact of halogens on gas-phase atmospheric chemistry, new particle formation, and climate. In this work, we present the application of mass spectrometric techniques for the quantification of short-lived iodine-containing volatiles emitted by eight different seaweeds from the intertidal zone of Helgoland, Germany. A previously developed online time-of-flight aerosol mass spectrometric method was used to determine I(2) emission rates and investigate temporally resolved emission profiles. Simultaneously, iodocarbons were preconcentrated on solid adsorbent tubes and quantified offline using thermodesorption-gas chromatography-mass spectrometry. The total iodine content of the seaweeds was determined using microwave-assisted tetramethylammonium hydroxide extraction followed by inductively coupled-plasma mass spectrometry analysis. The highest total iodine content was found in the Laminariales, followed by the brown algae Ascophyllum nodosum, Fucus vesiculosus, Fucus serratus, and both red algae Chondrus crispus and Delesseria sanguinea. Laminariales were found to be the strongest I(2) emitters. Time series of the iodine release of Laminaria digitata and Laminaria hyperborea showed a strong initial I(2) emission when first exposed to air followed by an exponential decline of the release rate. For both species, I(2) emission bursts were observed. For Laminaria saccharina und F. serratus, a more continuous I(2) release profile was detected, however, F. serratus released much less I(2). A. nodosum and F. vesiculosus showed a completely different emission behavior. The I(2) emission rates of these species were slowly increasing with time during the first 1 to 2 h until a more or less stable I(2) emission rate was reached. The lowest I(2) emission rates were detected for the red algae C. crispus and D. sanguinea. Total iodocarbon emission rates showed almost the same general trend, however, the total iodocarbon emission rates were about one to two orders of magnitude lower than those of molecular iodine, demonstrating that I(2) is the major iodine containing volatile released by the investigated seaweed species. In addition, a clear dependency of iodocarbon emission from the ozone level (0-150 ppb O(3)) was found for L. digitata.
从德国黑尔戈兰岛潮间带的 8 种不同海藻中，我们应用质谱技术定量测定了短寿命含碘挥发性物质的排放速率。我们提出了一种以前开发的在线飞行时间气溶胶质谱法，用于测定 I2 的排放速率并研究时间分辨的排放曲线。同时，将碘碳化合物预浓缩在固体吸附管上，并用热解吸-气相色谱-质谱法离线定量。采用微波辅助四甲基氢氧化铵提取法测定海藻中的总碘含量，然后用电感耦合等离子体质谱法分析。在 Laminariales 中发现了最高的总碘含量，其次是褐藻 Ascophyllum nodosum、Fucus vesiculosus、Fucus serratus 以及红藻 Chondrus crispus 和 Delesseria sanguinea。Laminariales 被发现是最强的 I2 排放源。Laminaria digitata 和 Laminaria hyperborea 的碘释放时间序列显示，当它们首次暴露在空气中时，会有强烈的初始 I2 排放，然后排放速率呈指数下降。对于这两个物种，都观察到了 I2 排放爆发。对于 Laminaria saccharina 和 F. serratus，检测到更连续的 I2 释放曲线，但 F. serratus 释放的 I2 要少得多。A. nodosum 和 F. vesiculosus 表现出完全不同的排放行为。这些物种的 I2 排放速率在最初的 1 到 2 小时内随着时间的推移缓慢增加，直到达到一个或多或少稳定的 I2 排放速率。在红藻 C. crispus 和 D. sanguinea 中检测到最低的 I2 排放速率。总碘碳排放速率表现出几乎相同的总体趋势，然而，总碘碳排放速率比分子碘低大约一到两个数量级，这表明 I2 是所研究的海藻物种释放的主要含碘挥发性物质。此外，在 L. digitata 中发现碘碳排放与臭氧水平（0-150 ppb O3）之间存在明显的依赖性。
