A second generation silicon isotope mass spectrometer

这项奖励将资助开发和购买一种新的质谱仪，用于测量海洋样品中的硅同位素比率。海洋硅同位素生物地球化学领域自20世纪90年代初由首席研究员开创以来，已有20多年的历史。加州大学圣巴巴拉分校的设施仍然是美国唯一的此类测量能力，尽管该领域已经发展到来自8个国家的18个以上实验室现在正在测量海洋系统中的硅同位素。硅同位素是了解海洋二氧化硅循环和具有硅壳的浮游生物对海洋生物地球化学的贡献的有力工具。生物成因二氧化硅和溶解硅酸中硅的同位素变化被用来限制现代海洋中二氧化硅的净生产率。利用从海洋沉积物中回收的硅藻锥体和海绵针状体的同位素组成的测量，重建了表层水域硅藻生产力的历史和深水硅酸含量随地质时间的变化。对于这个第二代硅同位素系统，研究人员正在与NU仪器有限公司合作，以NU透视同位素比质谱仪为基础创建一种商用仪器，通过对NU Carb和/或欧洲矢量热解进气系统(S)的改进而产生一个定制的进气系统。新仪器的两个主要目标是：1)将样品吞吐量提高4倍；2)将样品容量降低一个数量级。为了实现这些目标，将探索氟化硅的酸分解和热分解以产生分析物SiF4气体。第二代系统应该更快、更准确，与最初的原型和MC-ICP-MS等替代系统相比，新手使用起来要容易得多。这项研究的成功将恢复对美国海洋系统中硅同位素的常规测量。通过与Nu Instruments合作，将生产出一种商业仪器，与MC-ICP-MS等竞争技术相比，所有人都可以以相对较低的成本获得这种仪器，为这一领域的国家和国际能力建设做出贡献。最后，实现更大的样品吞吐量将既降低成本，又有助于使其他人能够获得拟议的仪器，从而进一步加快这一领域的进展。

This award would fund the development and purchase of a new mass spectrometer for the measurement of silicon isotope ratios in ocean samples. The field of marine silicon isotope biogeochemistry is about 20 years old having been pioneered by the lead investigator in the early 1990s. The UC Santa Barbara facility remains the only capability for such measurements in the U.S., although the field has grown to where over 18 laboratories from 8 countries are now measuring silicon isotopes in marine systems. Silicon isotopes are a powerful tool for understanding the marine silica cycle and the contribution of plankton with silica shells to marine biogeochemistry. Variations in isotopes of silicon in biogenic silica and in dissolved silicic acid are used to constrain net silica production rates in the modern ocean. Measurement of the isotopic composition of diatom frustules and of sponge spicules recovered from marine sediments are used to reconstruct the history of diatom productivity in surface waters and changes in deep water silicic acid content over geologic time. For this second-generation silicon isotope system, the investigator is partnering with Nu Instruments, Ltd. to create a commercially available instrument based on the Nu Perspective isotope ratio mass spectrometer, with a custom inlet system resulting from modifying the Nu Carb and/or the Eurovector pyrolysis inlet system(s). The two main goals for the new instrument are 1) to increase sample throughput by a factor of four and 2) to lower sample size by an order of magnitude. To meet these goals both acid and thermal decomposition of silicon fluorides to generate the analyte SiF4 gas will be explored. The second generation system should be faster, as or more precise, and much easier to use for the novice compared to the original prototype and compared to alternatives like MC-ICP-MS. Success in this development will restore routine measurements of isotopes of silicon from marine systems in the United States. By partnering with Nu Instruments, a commercial instrument will be produced that will be available to all at relatively low cost compared to competing technologies like MC-ICP-MS, contributing to national and international capacity building in this field. Finally, achieving higher sample throughput would both lower costs and facilitate the ability to make the proposed instrument available to others, further accelerating progress in the field.