A Carbon-13 Isotope Analyzer

碳同位素分析为研究代谢途径和追踪环境中的碳转化提供了宝贵的工具。该项目将尝试开发一种便于测量碳同位素(13C/12C)比值的光学技术。该仪器将利用线性光电二极管阵列来成像由含碳分子的等离子体发射产生的光谱。光谱处理算法将被用来消除光谱干扰，并校正由于样品压力和功率耦合的变化而引起的表观同位素比漂移。在这项第一阶段的研究中，将确定使用CO分子测定同位素比率的最佳带头。标准将包括12C同位素的其他转变造成的最小污染。将研究不同的激发源和样品制备技术，以便在第二阶段工作中将该仪器与自动碳-氮分析仪相连接。预计第一阶段工作的结果将能够确定碳的同位素比率，精确度为0.01%或0.1安培单位，这将使该方法既适用于自然丰度研究，也适用于示踪剂添加研究。与质谱仪相比，该仪器的相对简单和低成本将极大地扩展同位素丰度测量的应用。Aerodyne是一位已知的积极表演者，将为这项工作提供出色的支持。该产品一旦可用，将在需要处理大量碳同位素比样本的生态学研究中得到相当大的应用。

Isotopic carbon analysis provides a valuable tool for studies of metabolic pathways and for tracing carbon transformations in the environment. This project will attempt to develop an optical technique for the convenient measurement of carbon isotopic (13C/12C) ratios. The instrument will utilize a linear photodiode array to image the spectra arising from plasma emission of the carbon-containing molecules. Spectral processing algorithms will be applied to remove spectral interferences and to correct for apparent isotopic ratio shifts due to variations in sample pressure and power coupling. In this Phase I study, the optimal bandheads for isotopic ratio determination using the CO molecule will be identified. The criteria will include a minimal contamination from other transitions of the 12C isotope. Different excitation sources and sample preparation techniques will be studied with the intent of coupling the instrument to an automated carbon-nitrogen analyzer in the Phase II work. The results of the Phase I effort are expected to result in the ability to determine the isotope ratio of carbon to a precision of 0.01% or 0.1 & unit which would make the method applicable to both natural abundance studies and tracer addition studies. The relative simplicity and low cost of this instrument compared to mass spectrometers will greatly expand the applications of isotopic abundance measurements. Aerodyne is a known positive performer and will provide excellent support for the work. The product, when available, should find considerable use in ecological studies requiring the processing of large numbers of carbon isotope ratio samples.