Laser Spectroscopy of Iron Isotopes in Biological Samples to Analyze Iron Deficiency

Iron deficiency is a widespread global public health crisis, especially affecting infants, children, and pregnant women, where inadequate iron absorption can lead to irreversible cognitive and developmental damage. Although iron is abundant in nature, its bioavailability is highly variable and difficult to assess using conventional clinical methods. A proven approach uses stable rare isotopes of iron (Fe-57 and Fe-58) as safe tracers to directly measure absorption and metabolism. However, deployment has been limited by the high cost of mass spectroscopic methods for sensitive bloodwork analysis and the prohibitive cost of the enriched isotopes.

 

To overcome these limitations, we have developed fluorescence spectroscopy methods for detecting iron isotopes extracted from biological samples. Using dry-ashing techniques to rapidly convert blood samples into iron oxide, followed by laser ablation to generate an atomic iron beam, individual iron isotopes (Fe-54, Fe-56, Fe-57, and Fe-58) can be spectrally resolved. By scanning the 372 nm (⁵D₄ → ⁵F₅) transition, we have resolved the isotope peaks and their corresponding ratios from a 150 µg sample, corresponding to approximately three drops of blood. Now, we are working to increase the efficiency of our process to decrease the amount of blood needed for clinical pediatric applications.