coupled gas chromatography-molecular mass spectrometer-isotope ration mass spectrometer (GC-MS-IRMS)

新的地球生物学工作组需要一台气相色谱-分子三重四极杆质谱仪同位素比质谱仪(GC-MS/MS-IRMS)，它能够对物质混合物进行色谱分离，然后同时对有机分子及其组成的特定同位素比进行质谱分析。这种耦合的GC-MS/MS-IRMS由一个气相色谱-质谱仪(GC-MS)单元组成，该单元利用温度控制的色谱学提供生物标志物分子的分离、鉴定和定量。所要求的分子质谱仪包括一个三重四极分析器系统，即两个带有插入碰撞池(MS/MS)的四极分析器，以引起碰撞诱导的分子碎裂，以获得必要的结构信息。GC-MS/MS进一步提供了从复杂基质中过滤出低浓度物质并分别检测它们的可能性，这是简单的GC-MS不可能实现的。与带有上游氧化或还原反应器的同位素比质谱仪(IRMS)相结合，可以在一个测量周期内测定单个分析物的碳、氮或氢同位素，到目前为止，需要对不同仪器进行大量分析，并需要费力地调整单个仪器的参数，才能将测定的同位素值分配给各个分子峰。这类新的仪器不仅最大限度地减少了分析工作量，而且比现有的单个仪器有更高的分析产率，这对于通常物质数量很少的化石样本来说是一个决定性的优势。然而，这种创新的混合仪器可以实现高分辨率和高材料效率的分析，具有清晰的色谱峰，并同时测定单个化合物的碳、氮和氢同位素比率。有机分子的分子结构提供了有关相关有机体群和沉积条件的信息，而被分析脂类的13C、15N、H/D同位素提供了有关生物体的食物来源和代谢途径的信息。这一补充信息对于确定生物合成途径是必不可少的，对于明确分配生物标志物也是决定性的，不仅是对一组特定的生物体，而且对各自的生物地球化学过程或(古)环境条件也是如此。在地质矿物学研究所内，工作组地质生物学(主要用户、仪器操作员)、工作组环境同位素地球化学和工作组第四纪地质工作组将使用应用的GC-MS/MS-IRMS，借助生物标志物及其特定成分的同位素分馏，重建古化石沉积环境。

A coupled gas chromatography-molecular triple quadrupole mass spectrometer isotope ratio mass spectrometer (GC-MS/MS-IRMS) is requested for the new Geobiology working group, which enables the chromatographic separation of a substance mixture and subsequently the simultaneous mass spectrometric analysis of the organic molecules and their component-specific isotope ratios.This coupled GC-MS/MS-IRMS consists of a gas chromatography-mass spectrometry (GC-MS) unit that provides the separation, identification and quantification of biomarker molecules using temperature-controlled chromatography. The requested molecular mass spectrometer consists of a triple quadrupole analyser system, i.e. two quadrupole analysers with interposed collision cell (MS/MS) to cause collision-induced fragmentation of molecules to obtain essential structural information. GC-MS/MS further offers the possibility to filter out low concentrated substances from complex matrices and to detect them separately, which is not possible with a simple GC-MS. The coupling with the isotope ratio mass spectrometer (IRMS) with upstream oxidation or reduction reactors enables the determination of the carbon, nitrogen or hydrogen isotopy of the individual analytes within one measuring cycle.Until now, numerous analyses on different instruments were necessary and the laborious adjustment of the individual instrument parameters was required to assign the determined isotope values to the respective molecular peaks. This new class of instruments not only minimises the analytical effort, but also allows a much better analytical yield than the available individual instruments, which is a decisive advantage for the often small substance quantities of fossil samples. However, this innovative hybrid instrument allows high-resolution and material-efficient analyses with clear chromatogram peaks and simultaneous determinations of the carbon, nitrogen and hydrogen isotope ratios of the individual compounds. While the molecular structures of the organic molecules provide information about the associated organism groups and deposition conditions, the 13C, 15N, H/D isotopies of the analysed lipids provide information about food sources and metabolic pathways of the organisms. This additional information is essential for the determination of biosynthetic pathways and also decisive for the clear assignment of biomarkers, not only to a specific group of organisms, but also to the respective biogeochemical processes or the (palaeo-)environmental conditions. Within the Institute of Geology and Mineralogy, the working groups WG Geobiology (main user, instrument operator), WG Environmental Isotope Geochemistry and WG Quaternary Geology will use the applied GC-MS/MS-IRMS for palaeoreconstructions of fossil depositional environments with the help of biomarkers and their component-specific isotope fractionations.