Isotope Ratio Monitoring GC-MS

The measurement of isotope ratios was the first mass spectrometry application. In 1907, Thomson for the first time showed the parabola mass spectrum of a Neon sample with his newly developed mass spectrometer. Later, in 1919, Aston concluded that the observed lines reveal the isotopes 20 and 22 of Neon. He later 

Isotope ratio monitoring techniques using continuous flow sample introduction via GC had been introduced in the 1970s and developed into a mature analytical technology very quickly. Already in 1976, the first approach hyphenating a capillary GC with a magnetic sector MS for the systematic measurement of isotope ratios was published (Sano et al., 1976). The continuous flow determination of individual compound ratios was introduced by Matthews 

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The carbon isotopic composition of individual compounds in gases, oUs, condensates, and source rock extracts is measured by GC-combustion-isotope ratio MS (GC-C-IRMS) or isotope ratio monitoring GC-MS (irm-GC-MS). This is a specifically designed capillary GC MS system in which hydrocarbon components from the GC effluent are combusted to carbon dioxide (CO2) and water (H2O). The CO2 of combustion is continuously analyzed on-line by a triplecollector isotope-ratio mass spectrometer to provide precise ratio mea-... 

The compound specific isotope analysis (CSIA) has been successfully used in the assessment of in situ remediation of contaminated environments, identification of pollutant degradation pathways, or the verification of contaminant sources. In these types of studies, the sensitivity of isotope ratio monitoring GC-MS (irm-GC-MS) is often a limiting factor, since concentrations of organic contaminants in groundwater are very often in the low pg/L range. Hence, in order to be able to routinely use irm-GC-MS techniques in environmental studies, efficient extraction procedures are required. 

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