ISOTOPE RATIO MONITORING MASS SPECTROMETER

华盛顿大学光谱设备的功能是 一个地方、区域、国家和国际的大众资源 自1969年我们的第一台仪器投入使用以来， 操作 在此期间，该设施已发展到 包括5台四极GCMS仪器、1台LCMS仪器、1台质量 选择性检测器，双聚焦扩展质量范围 仪器和自动同位素比率系统。 在过去 2011年，该设施记录了7810小时的仪器时间， 样品分析 据我们所知，我们是唯一的NIH质谱资源 提供常规、高稀释度、高精度、双进双出、 收集器同位素比分析，以生物医学界。 的 用于这一目的的仪器是用当地资金购买的 在“最小”配置中。 因为，在那个时候， 商用自动化IRMS机器，自动化和 仪器的软件控制在设施中实现。 由于最初的制造商设计/结构缺陷， 仪器从未在预期规格范围内运行， 总是受到不可接受的"停机时间"的影响。 此外，本发明还 因为开发硬件和软件的人 这个工具现在已经让资源，它已经成为 越来越难以维持这种"非标准" 仪器在面对不断增加的，沉重的样品负荷。 我们正在寻求支持，以购买一个当前的，自动化的同位素 比率仪器与制造商的数据系统，使我们能够 继续为全国用户群提供IRMS服务。 此外，由于a）目前发展的一大部分 人体稳定同位素示踪动力学的工作涉及前体- 产物关系，B）常规GCMS通常不 灵敏度足以测量产物同位素富集， 在前体中产生"非示踪剂"质量扰动效应 c）IRMS需要困难的样品制备才能获得 IRMS同位素分析所需的高纯度产品，我们 请求GC/combustion/IRMS接口， 生物样品中产物同位素富集度的测定 稀释度高于传统离子的稀释度 监测GCMS。

The Washington University Spectrometry Facility has functioned as a local, regional, national, and international resource for mass spectrometry since 1969 when our first instrument was put into operation. In the intervening years, the facility has grown to include 5 quadrupole GCMS instrument an LCMS instrument, a mass selective detector, a double focusing extended mass range instrument, and an automated isotope ratio system. In the last year, this facility logged 7810 hours of instrument time for actual sample analysis. To our knowledge, we are the only NIH Mass Spectrometry Resource providing routine, high dilution, high precision, dual-inlet dual- collector isotope ratio analyses to the biomedical community. The instrument used for this purpose was purchased with local funds in a "minimal" configuration. Since, at the time, there were no commercially available automated IRMS machines, automation and software control of the instrument was implemented in the facility. Because of initial manufacturer design/construction flaws, this instrument has never functioned within expected specifications an has always been subject to unacceptable "down time". Further, since the individual who developed the hardware and software for this instrument has now let the resource, it has become increasingly more difficult to maintain this "non-standard" instrument in the face of an increasing, heavy sample load. We are asking for support to purchase a current, automated isotope ratio instrument with the manufacturer's data system to allow us to continue to provide IRMS services to the national user's group. In addition, since a) a significant fraction of current development work in human stable isotope tracer kinetics involves precursor- product relationships, b) conventional GCMS is generally not sensitivity enough to measure product isotope enrichments without producing "non-tracer" mass perturbation effects in the precursor pool, and c) IRMS requires difficult sample preparation to obtain the highly pure product required for IRMS isotopic analyses, we are requesting a GC/combustion/IRMS interface to allow facile determination of product isotopic enrichments in biological samples at dilutions higher than those possible by conventional ion monitoring GCMS.