Applications of nuclear and conventional methods to evaluate trace metal concentrations in biological specimens for biomonitoring in epidemiology.

Abstract

Trace metals are crucial to human health and have the potential to influence the prevention and treatment of various diseases. Imbalances in element concentrations are linked to numerous health conditions, with particular emphasis on cancer. Elements such as Zn, Ca, Fe, Mg, and Se play essential roles in cellular function, affecting cancer progression and development. Conversely, toxic metals such as Cd, Br, and Pb are associated with adverse health effects, including carcinogenesis. Understanding the concentrations of these metals in biological tissues is therefore essential for improving diagnosis and treatment of such conditions. Although a wide range of analytical methods is available for measuring trace metals in biological samples, this work focuses on nuclear techniques such as Instrumental Neutron Activation Analysis (INAA) and conventional methods such as Inductively Coupled Plasma–Mass Spectrometry (ICP-MS). INAA is particularly valuable because it allows for non-destructive analysis of biological samples, including biopsies or nails, without requiring sample pretreatment. This technique can reliably measure the concentration of elements across much of the periodic table, making it a powerful tool for trace metal analysis. This dissertation develops the integration of conventional and non-conventional analytical techniques to enhance trace metal analysis in biological samples as potential bio-monitors. By combining INAA with ICP-MS, this work provides a comprehensive approach to analyzing trace metals, especially for elements with challenging analytical properties--such as those with long half-lives, small cross-sections, and numerous interference signals. Specifically, this research investigates trace metals Zn, Ca, Fe, Mg, Se, Cd, Pb, and Br in limited-quantity biopsy tissues and human nail clippings. Additionally, this work compares the effectiveness of INAA with that of a Triple Quadrupole ICP-MS, a more advanced model, to evaluate its ability to overcome certain limitations inherent to traditional ICP-MS techniques.