Isotopically enriched spikes of naturally occurring elements have experienced increasing interest ever since the original idea by Nobel Laureate George de Hevesy in the early 20th century. For example, isotopic spikes have been administered to biological systems for the monitoring of ecosystem fluxes or as promising tool to investigate elemental behavior and deposition during metabolism in plants, animals or humans. In this context, (multiple) isotopic spikes offer the opportunity to provide unique fingermarks for valuable goods, artefacts, hazardous substances or to study and better understand industrial processes by marking specific steps in the production process. Isotope pattern deconvolution (IPD), based on multiple linear regressions, is the mathematical tool of choice. IPD allows for deconvolving these isotope pattern without knowing the quantities of different isotope sources incorporated and mixed into the sample, as well as the degree of impurities and species-interconversion.

In this talk, we will discuss the key insights and capabilities of this approach, along with the associated challenges and the critical importance of rigorous study design. Specific examples of Mg, Ca, Sr, Ni, and Pb demonstrate the broad potential and versatility of enriched isotopic tracers, each presenting unique analytical challenges while revealing new advantages of the methodology. We will explore a range of studies across diverse fields, including biology, clinical and medical research, material sciences, and advanced industrial processes.