Charles Lesher, PhD - Department of Earth and Planetary Sciences

Trace metals in dried blood spots: Method development for biomarkers in case-control studies by laser ablation inductively coupled plasma mass spectrometry
The major drawback for epidemiologic case-control studies, the most feasible design for rare diseases, is the difficulty in reconstructing accurate exposure levels retrospectively. Newborn dried blood spots (DBS) provide a window into the prenatal period, which is widely considered critical for early development of brain, endocrine, respiratory and other systems, and are available to researchers for all births in California and numerous other states. The ability to characterize metals and minerals using small amounts of DBS will meet an acute need in children's environmental health. We have previously developed capabilities to quantify Hg in DBS using laser ablation inductively coupled plasma mass spectrometry (LA-ICPMS), and further explored the potential of using this analytical method to measure Pb and Zn. Our work highlights the advantages of LA-ICPMS over alternative methods, but further work is required to evaluate and mitigate background contamination and matrix effects. We propose to verify the laser ablation method using matrix-matched DBS standards. These reference standards will be used in an interlaboratory comparison study. Our work will extend and improve the analytical protocols for LA-ICPMS of DBS for As, Cd, Mn, Fe, Se, as well as Pb, Zn and Hg. This development work is critical for future comprehensive epidemiologic studies involving newborn dried blood spots.