A second generation silicon isotope mass spectrometer

该奖项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在20世纪90年代初由首席研究员开创，至今已有20年的历史。加州大学圣巴巴拉分校的设施仍然是美国唯一能够进行此类测量的设施，尽管该领域已经发展到现在来自8个国家的18个实验室正在测量海洋系统中的硅同位素。硅同位素是了解海洋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同位素的变化被用来限制现代海洋中二氧化硅的净产量。通过测量海洋沉积物中硅藻体和海绵针状体的同位素组成，重建了地表水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 Perspective同位素比值质谱仪为基础，创建一种商用仪器，并通过修改Nu Carb和/或Eurovector热解入口系统来定制入口系统。新仪器的两个主要目标是1)将样品吞吐量提高四倍，2)将样品大小降低一个数量级。为了实现这些目标，将探索酸分解和热分解氟化硅以产生分析物si4气体。与原始原型和MC-ICP-MS等替代品相比，第二代系统应该更快，或者更精确，并且对新手来说更容易使用。这一发展的成功将恢复美国海洋系统中硅同位素的常规测量。通过与Nu Instruments的合作，将生产出一种商用仪器，与MC-ICP-MS等竞争技术相比，这种仪器将以相对较低的成本提供给所有人，有助于该领域的国家和国际能力建设。最后，实现更高的样品吞吐量既可以降低成本，又可以促进将拟议的仪器提供给其他人的能力，从而进一步加快该领域的进展。

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.