The development of multiple collector mass spectrometry for isotope ratio measurements

Abstract

Multiple collector mass spectrometry has enabled significant advances in our understanding of geological, biological, nuclear, and physical processes in terrestrial and extra-terrestrial environments. The development of improved mass spectrometers and more efficient and universal ionization techniques is driven by the requirement to extract the highest quality information from the smallest amount of sample possible. Important milestones include the refinement of the variable multiple collector system, improvements in current amplifier technology to achieve ultimate precision and accuracy, increased abundance sensitivity, tailored ion optics using zoom optics and increased ion optical magnification to meet the special requirements of multiple collection, increased signal-to-noise using multiple ion counting devices, and the integration of a high efficiency ionization inductively coupled plasma source. New applications are on the horizon in many fields in addition to the geological and cosmological origins of high precision isotope ratio mass spectrometry. This is made possible by in situ sampling of samples at high spatial resolution using laser ablation techniques as well as online coupling of chromatographic devices to study elemental isotope effects in isolated molecular species. This paper describes and discusses the instrumental development of multiple collector isotope ratio technology and highlights some emerging applications.