Development of Organic H, C, and N Stable Isotope International Standards for NIST and IAEA: Multi-laboratory Expert Calibration in Support of GC, LC, and EA-IRMS Measurement Sci.

这一拟议的多实验室项目旨在开发急需的有机氢、碳和氮同位素标准物质(RMS)，这些物质将以可靠的RMS库存为国际社会服务一到几十年。现代半自动稳定同位素比分析(SIRA)与在线元素分析(EA)、气相色谱(GC)或液相色谱(LC)与同位素比质谱仪(IRMS)相结合的连续流动模式已成为气候变化监测、生态学、环境科学、化石燃料和生物燃料科学、食品科学、法医学和医学科学研究中常规和宝贵的工具。要准确测定氢、碳和氮的稳定同位素组成，需要使用至少两个具有不同同位素组成的同位素均方根(也称为标准)进行校准，以(I)固定同位素标尺和(Ii)补偿通常压缩同位素标尺的仪器的操作差异。合适的有机稳定同位素RMS的发展跟不上分析连续流动方法的快速发展。美国传统上在稳定同位素RMS的开发方面一直处于国际领先地位，但美国国家标准与技术研究所(NIST，前身为NBS)现在无法充分满足科学界对稳定同位素RMS的需求。因此，科学界被迫使用临时的实验室同位素RMS，从而危及不同实验室之间的科学结果的相互兼容性。我们的几个新的有机同位素RMS将是NIST的第一个也是唯一一个用于H、C和N同位素校准的现代气相色谱和液相色谱方法的RMS。拟议项目的另一个结果将是相对于界定尺度的国际测量标准，为所有无机和有机氢有效值建议改进的、准确校准的氢同位素组成。新开发的RMS将通过NIST和IAEA进行分发，也将通过折扣渠道支持NSF资助的应用。化学和生物海洋学、生态系统和地球生物学/低温地球化学领域使用稳定的同位素分析作为发现和创新的基石。他们显然将受益于拥有标准材料的来源，这样来自这些社区的结果就可以进行精确的比较。除地球化学以外的其他领域将受益于新的稳定同位素RMS，例如生物燃料能源研究、污染物和动物的法医追踪、生物学和生态学(例如营养研究)、医学(诊断医学疾病)、药理学(药物鉴定)、刑事司法(人体遗骸的地理追踪)和食品科学(食品鉴定)。PI一直在志愿开展外展工作，例如向当地童子军教授地质学功勋徽章。当向年轻听众或公众解释稳定同位素研究的使用时，人们总是对突出的法医例子反应热烈，以及我在印第安纳大学实验室的RMS正被联邦调查局、环境保护局、国际原子能机构、美国和国际海关当局使用的事实。这项研究的结果也将在伊利诺伊州十字路口地质项目上展示，这是S系研究生举办的一项活动，旨在与本科生、其他机构的毕业生和行业参观者分享研究成果。

This proposed multi-laboratory project aims to develop urgently needed organic hydrogen, carbon, and nitrogen isotopic reference materials (RMs) that will serve the international community for one to several decades with reliable stocks of RMs. Modern, semi-automated stable isotope-ratio analysis (SIRA) in continuous flow mode with on-line elemental analysis (EA), gas chromatography (GC), or liquid chromatography (LC) interfaced with isotope ratio mass-spectrometry (IRMS) has become a routine and invaluable tool in monitoring of climate change, studies of ecology, environmental sciences, fossil fuel and biofuel sciences, food science, forensics, and medical sciences. Accurate determinations of hydrogen,carbon, and nitrogen stable isotopic compositions require a calibration using at least two isotopic RMs (also called standards) having different isotopic compositions to (i) anchor the isotopic scale and (ii) compensate for differences in operation of instruments, which commonly compress isotope scales. The development of suitable organic stable isotope RMs has not kept pace with the rapid development of analytical continuous flow methods. The U.S. traditionally has been an international leader in the development of stable isotopic RMs, but the National Institute of Standards and Technology (NIST, formerly NBS) now fails to adequately serve the stable isotopic RM needs of the scientific community. As a result, the scientific community is forced to work with temporary laboratory isotopic RMs jeopardizing the mutual compatibility of scientific results among different laboratories. Several of our new organic isotopic RMs will be the first and only RMs for NIST for H, C, and N isotopic calibration of modern gas chromatographic and liquid chromatographic approaches. An additional result of the proposed project will be to recommend improved, accurately calibrated hydrogen isotopic compositions for all inorganic and organic hydrogen RMs relative to the scale-defining international measurement standards. Distribution of newly developed RMs will occur via NIST and IAEA, and also via discounted channels to support NSF-funded applications.The fields of chemical and biological oceanography, ecosystems, and Geobiology/low-temperature geochemistry use stable isotope analyses as cornerstones for discovery and innovation. They will obviously benefit from having a source of standard materials, so that the results coming from these communities can be precisely compared. Diverse fields beyond geochemistry will benefit from new stable isotopic RMs, e.g. biofuel energy research, forensic tracing of contaminants and animals, biology and ecology (e.g., trophic research), medical science (diagnosing medical disorders), pharmacology (drug authentication), criminal justice (geographic tracing of human remains), and food science (food authentication). The PI has been volunteering in outreach efforts, for example by teaching the Geology Merit Badge to local boy scouts. When the use of stable isotope research was explained to young listeners or the public, the response was always enthusiastic to prominent forensic examples and the fact that RMs from my laboratory at Indiana University are being used by the FBI, EPA, IAEA, U.S. and international customs authorities. Results of this research will also be presented at the IU Crossroad Geology Program, which is an event run by the department?s graduate students aimed at sharing research with undergraduates, graduates from other institutions, and to visitors from industry.