Acquisition of an HPLC and GC-IRMS for Oceanographic, Biological and Environmental Engineering Research on Stable Isotope Composition of Individual Compounds

请求提供资金，以购买一台气相色谱-同位素比质谱仪。该仪器允许测量各种有机分子的碳和氮稳定同位素比率，基本上所有那些可以通过气相色谱法解析或可以转化为合适的挥发性衍生物的有机分子。此外，还要求提供资金，用于建立一个离线自动化高效液相色谱系统，以便为随后的离线综合资源监测系统分离特定化合物。 这种方法对于某些不挥发性太强或缺乏足够热稳定性的化合物是必需的;对于需要广泛衍生化的化合物，如氨基酸，也更方便。 这些仪器加在一起将构成一个设施，可以测量几乎任何有机物质的碳和氮同位素组成。 具体而言，HPLC和GC-IRMS将用于测定氨基酸和脂肪酸的稳定同位素组成，以研究海洋哺乳动物的生长速率和营养动力学。海洋和湖泊沉积物中的特定有机化合物，如氨基酸、碳水化合物、碳氢化合物和脂类的稳定同位素组成将用于调查这些物质的来源和成岩蚀变，协助研究北方高纬度地区的环境变化。此外，这些仪器还将用于大型哺乳动物新陈代谢的示踪调查，方法是测量挥发性脂肪酸等代谢物的同位素组成随时间的变化。最后，GC-C-IRMS将用于区分天然存在的碳氢化合物和石油衍生污染物。

Funding is requested to purchase a gas chromatograph-isotope ratio mass spectrometer (GC-CIRMS). This instrument permits the measurement of carbon and nitrogen stable isotope ratios of a wide variety of organic molecules, essentially all of those which can be resolved by gas chromatography or which can be converted to a suitable volatile derivative. Also, funds are requested for an off-line, automated high-performance liquid chromatography (HPLC) system for isolation of specific compounds for subsequent, off-line, IRMS. This approach is needed for certain compounds which are too involatile or lack sufficient heat stability for GC; it also can be more convenient for compounds, such as amino acids, which require extensive derivatization for GC. Together, these instruments would constitute a facility that could measure the C and N isotopic composition of virtually any organic substance. Specifically, the HPLC and GC-IRMS would be used to measure the stable isotope composition of amino acids and fatty acids in the course of studies of the growth rate and trophic dynamics of marine mammals. The stable isotope composition of specific organic compounds, such as amino acids, carbohydrates, hydrocarbons, and lipids, from marine and lake sediments would be used in investigations of the sources and diagenetic alteration of these substances, assisting studies of environmental change at high northern latitudes. Also, the instruments would be used in tracer investigations of the metabolism of large mammals by measuring changes over time in the isotopic composition of metabolites such as volatile fatty acids. Finally, the GC-C-IRMS would be used to distinguish naturally-occurring hydrocarbons from petroleum-derived contaminants.