A Carbon-13 Isotope Analyzer Based on CO Emission Spectroscopy

同位素碳分析提供了一个有价值的工具， 研究代谢途径和碳追踪 环境的变化。 PI建议开发 一种方便测量碳的光学技术 同位素（13 C/12 C）比值。 仪器将使用线性 光电二极管阵列，用于对等离子体发射产生的光谱成像 含碳分子。 算法将应用于 消除光谱干扰，校正同位素比值 由于样品压力和功率耦合的变化而产生的偏移。 初步工作表明，排放系统可以 用于测定CO2样品中的13 C/12 C比率， 相对精密度为2.5%，可提高1倍 6. 还对数据处理的数学方法进行了评价。 第二阶段拟议的后续研究将涉及调整 测定CO_2淋洗液~（13）C/~（12）C比值排放法 从气相色谱仪上。 系统改进，包括 设计和测试一个适合于取样的入口系统， 大气压力，可能导致自动化的样品处理 该系统将耦合到碳氮分析仪， 13 C和15 N的在线同位素比测定。 成功实现第二阶段的目标 应该导致开发一种廉价，可靠的 质谱法的替代方法 13 C和最终15 N的同位素比率，以及来自相同的18 O sample. 该仪器可方便地用于示踪剂研究， 如果进一步改进， 分析，在医疗和环境领域，从而使 同位素测量更容易获得更广泛的 研究人员

Isotopic carbon analysis provides a valuable tool for studies of metabolic pathways and for tracing carbon transformations in the environment. The PI proposes to develop an optical technique for the convenient measurement of carbon isotopic (13C/12C) ratios. The instrument will use a linear photodiode array to image the spectra arising from plasm-emission of carbon-containing molecules. Algorithms will be applied to remove spectral interferences and to correct for isotopic ration shifts due to variations in sample pressure and power coupling. Initial work demonstrated that an emission system could be used to determine the 13C/12C ratio in CO2 samples up to a relative precision of 2.5% which could be improved by a factor of 6. Mathematical methods were also evaluated for data processing. Follow-on studies proposed in phase II will involve adapting the emission method for determining 13C/12C ratios for CO2 eluant from a gas chromatograph. System refinements, including the design and testing of an inlet system suitable for sampling at atmospheric pressure, may lead to an automated sample processing system which will be coupled to a carbon-nitrogen analyzer for on-line isotope ratio determinations of both 13C and 15N. Successful accomplishment of the objectives of phase II should result in the development of an inexpensive, reliable alternative to mass spectrometry for the determination of the isotopic ratios of 13C and eventually 15N, and 18O from the same sample. The instrument could be readily used for tracer studies, and with further refinements may be useful for natural abundance analyses, in both medical and environmental fields thereby making isotopic measurements more accessible to a broader range of researchers.