62883 2025 eng lecture 0 -- -- -- Stable metal isotopes receive increasing attention as medical biomarkers due to their potential to detect changes of the metal metabolism related to disease. Potential mechanisms causing isotope fractionation include biological processes that involve redox- or bond-forming reactions and interaction of metals during transmembrane import and export. In order to advance our understanding of the underlying processes responsible for isotope fractionation between normal and diseased cells, we need in situ, spatially resolved methods. Despite its frequent use, laser ablation - multi-collector - inductively coupled plasma mass spectrometry (LA-MC-ICPMS) analysis of biological material is severely limited by the scarcity of matrix-matched standards. Such matrix-matched standards are necessary to correct for instrumental sources of isotope fractionation such as particle size distribution, ablation physics and differential ionization. Copper stable isotopes have proven to be a particularly powerful tool to identify differences in isotope composition between tumors and healthy tissue suggesting application in cancer diagnosis [1, 2]. To further our knowledge of Cu isotope fractionation processes induced by diseases we have developed gelatin-based bracketing standards allowing to correct instrumentally induced isotope fractionation during LA-MC-ICPMS analysis. Since gelatin properties resemble properties of protein-rich cellular material, they mimic biological matrices and their ablation behaviour. Hence, gelatin standards are spiked with known amounts of Cu stable isotopes of a known Cu isotope composition and used as matrix-matched bracketing standard. The method achieved reproducibilities of better than 0.15‰ (2SD) for inorganic reference materials and reproducibilities of better than 0.17‰ (2SD) for biological reference materials. The developed routine was tested on a liver tumor model and in situ Cu isotope compositions between healthy (δ65/63Cu = -1.5 to 0.2 ‰) and tumorous (δ65/63Cu = 0.0 to 1.3 ‰) liver tissue could be distinguished [3]. ANAKON 2025 Leipzig, Germany 10.03.2025 10.03.2025 0 publish false true Mathias Schannor eng uncontrolled Laser Ablation eng uncontrolled Reference Material eng uncontrolled Biomarker Analytische Chemie 1 Analytische Chemie; Referenzmaterialien 1.1 Anorganische Spurenanalytik Chemie und Prozesstechnik Chemische Charakterisierung und Spurenanalytik Datei im Netzwerk der BAM verfügbar ("Closed Access") Präsentation