Acquisition of Stable Isotope Ratio Mass Spectrometer and Sample Preparation Systems

1. 我们计划在加州大学戴维斯分校建立一个稳定同位素设施，包括两台同位素比质谱仪、两台元素分析仪以及用于样品制备和数据分析的相关设备。其中一个质谱仪将是一个高通量，中等分辨率的仪器，将专门用于分析富集样品；另一种是通量较低，但分辨率较高的仪器，专门用于分析自然丰度水平的变化。该设施将加快需要稳定同位素的实验，包括：(a)土壤养分和水分运动的实地研究，(b)碳固定途径、植物水分利用效率和氮利用的测定，以及(c)代谢和养分吸收的测量。目前，我们的分析是在校外许多不同的地点进行的。不仅一致性难以保证，而且高昂的费用也限制了这类分析在外部支持下的研究。更糟糕的是，漫长的周转时间——有时延长到近一年——严重损害了我们的实验协议。加州大学戴维斯分校拟议的稳定同位素设施应该可以缓解这些问题。加州大学戴维斯分校植物和环境科学专业的学生、教师和工作人员将可以使用拟议中的设施。这7个pi与9个研究生项目有关。在过去的十年中，有1134名学生从加州大学戴维斯分校的这些项目中获得了研究生学位，目前有364名研究生在读。这些学生中的很大一部分将从拟议的设施中受益，无论是通过课程作业还是通过他们的独立研究项目。有了校园里的设备，学生们可以准备自己的样品进行分析，以降低成本，并提供使用这些技术的直接经验。因此，更多的学生可能会将稳定同位素纳入他们的方案中。

1. PROJECT SUMMARY We propose to establish a stable isotope facility at UC Davis containing two isotope-ratio mass spectrometers, two elemental analyzers, and associated equipment for sample preparation and data analysis. One of the mass spectrometers would be a high throughput, medium resolution instrument that would be dedicated to the analysis of enriched samples; the other would be a lower throughput, but higher resolution instrument, dedicated to the analysis of variation in natural abundance levels. This facility would expedite experiments that require stable isotopes including (a) field studies of soil nutrient and water movement, (b) determination of carbon fixation pathway, plant water use efficiency, and nitrogen utilization, and (c) measurements of metabolism and nutrient uptake. At present, our analyses are conducted off-campus at many different locations. Not only has uniformity been difficult to insure, but the high expense has limited such analyses to research with extramural support. Worse, long turnaround times-- sometimes extending to nearly a year--have seriously compromised our experimental protocols. The proposed stable isotope facility at UC Davis should alleviate these problems. Students, faculty, and staff in the plant and environmental sciences at UC Davis would have access to the proposed facility. The seven PIs are associated with nine graduate programs. During the last decade, 1134 students have received graduate degrees from these UC Davis programs, and 364 graduate students are currently enrolled. A significant percentage of these students would benefit from the proposed facility, either through course work or through their independent research programs. With a facility on campus, students could prepare their own samples for analysis to reduce costs as well as to provide direct experience using these techniques. Thus, more students would be likely to incorporate stable isotopes into their protocols.