Mass spectrometry traditionally requires material to be extracted in bulk from samples, at the expense of information about the complex spatial relationships of the individual components. However, to understand large-scale phenomena, such as ore-producing hydrothermal systems, or nutrient trafficking in terrestrial and marine ecosystems, researchers are increasingly looking at the chemical processes occurring at the micro-to nano-scale.
Secondary Ion Mass Spectrometry (SIMS) provides chemical and isotopic analysis on micro-volumes of sample, in situ, while NanoSIMS allows imaging at the sub-micron scale. Combining stable isotope labelling with NanoSIMS allows us to directly visualise the distribution of labelled components within an experimental system, without changing its chemical nature. For example, 15N and 13C labels can be attached to specific molecules used in biological systems (nutrient tracking, drug delivery), and deuterated-18O labelled water may be used to investigate mineral-fluid interactions. Furthermore, isotopic labels can be conjugated to specific antibodies to identify proteins, or to oligonucleotides to identify specific species of bacteria.