Gas Source Isotope Ratio Mass Spectrometry (IRMS)

Abstract

Gas source isotope ratio mass spectrometry is usually referred to as isotope ratio mass spectrometry (IRMS) or stable-isotope ratio mass spectrometry (SIRMS). IRMS is a conventional method for measuring isotope ratios and has benefited from more than 65 years of research and development. Modern mass spectrometers are all based on gas source isotope ratio mass spectrometry field mass separators. More recently, the development of high-resolution sector field devices has added a new dimension to IRMS. Modern instruments achieve a high sample throughput, which is a prerequisite, e.g., for ecosystem studies where usually a large number of samples needs to be analysed and high precision is required. IRMS is used specifically for the measurement of stable-isotope ratios of a limited number of elements (C, H, N, O and S) after transfer into a gaseous species. Si, Cl, Br and Se can be added to the list even though their applications are limited compared to the other isotope systems. A concise overview of the technical background is given here as well as numerous applications of this technique in earth and geosciences, paleoclimate research, cosmochemistry, environmental sciences and life sciences.

Mass Spectrometry‐based Techniques for Direct Quantification of High Ionization Energy Elements in Solid Materials—challenges and Perspectives

“…To conclude, due to several reasons, the ionization of highly electronegative elements is less efficient than other elements complicating their determination by mass spectrometric techniques. The presence of spectral interferences may also cause additional difficulties; however, this problem is to a certain extent present in all ionization sources and often requires special efforts to acquire the accurate results such as the use of higher resolution mass analyzers (Brand et al, 2015; Bürger et al, 2015; Jakubowski et al, 2015; Sangely et al, 2015; Venzago & Pisonero, 2015) or, for example, the use of ion reactions in collision reaction cell technology in ICP‐MS (Tanner, Baranov, & Bandura, 2002; Yamada, 2015). Notably, the interferences are mainly dependent on the mass range rather than the ionization energy of the elements, medium masses (ca.…”

“…That is why TIMS and IRMS are not considered in the current review in much detail. The readers are referred to more specialized publications in this respect, for example (Benson et al, 2006; Brand et al, 2015; Bürger et al, 2015; Gentile et al, 2015; Aggarwal, 2016; Matos & Jackson, 2019).…”

“…The determination of the isotopic composition of N, O, Cl, and, to the lesser extent Br, is widely used in earth sciences, cosmology, archeology, paleontology, forensics, etc. (Benson et al, 2009; Drivelos & Georgiou 2012; Ireland, 2013; Brand et al, 2015; Sevastyanov, 2015; Zimmermann, Halloran, & Hunkeler, 2020). Fluorine has only a single naturally present isotope so the isotopic analysis is not applicable for it.…”

“…IRMS requires sample conversion into the gaseous form which is achieved via several approaches. These include simple combustion of the samples similar to quantitative CNO‐analysis, the use of gas or liquid chromatography mainly for organic compounds or laser ablation for direct isotopic analysis of solids (Brand et al, 2015). Automatized IRMS systems are commercially available for both sample preparation and isotopic analysis of light isotopes.…”

“…To ensure the absence of matrix effects and spectral interferences, the sample preparation in TIMS is normally very arduous requiring quantitative separation of the analyte from the sample matrix (Ireland, 2013; Sevastyanov, 2015). The correct sample preparation ensures high accuracy of isotopic ratios measurements for О, N (Ireland, 2013; Brand et al, 2015; Kelly, Brodie, & Hilkert, 2018), and Cl (Godon et al, 2004; Brand et al, 2015; Zimmermann, Halloran, & Hunkeler, 2020).…”