Spectroscopic methods for isotope analysis of heavy metal atoms: A review

Heavy metals migrate throughout the ecosystem with water cycling, posing a significant threat to food safety, environmental safety, and human health. Atomic spectrometry has many advantages, such as rapid, real-time, in situ, and high resolution, and has great application potential in heavy metal isotope analysis in environmental monitoring, biomedicine, and nuclear fuels. The present article reviews the progress of atomic spectrometry for heavy metal isotope analysis, classified into linear spectroscopic methods (atomic emission, atomic absorption, and laser-excited atomic fluorescence spectrometry) and non-linear spectroscopic methods (saturated absorption spectrometry, four-wave mixing spectrometry, and Doppler-free two-photon spectrometry). It mainly focuses on the principles and applications in analyzing the heavy metal isotopic concentration and energy level structure. It also summarizes the fundamentals of isotope analysis according to the considerations of choosing spectroscopic methods for isotope analysis, which include the isotope shifts of a set of heavy metal transitions, the characteristics of atomic spectrometry, and related instrumentation. Finally, it discusses the advantages and disadvantages compared with mass spectrometry and an outlook of challenges and research opportunities within the field.