Researchers from the Institute of Modern Physics of the Chinese Academy of Sciences, in collaboration with Beijing Normal University, Shenzhen Technology University, and Tianjin University, have developed a novel two-dimensional coincidence time-of-flight mass spectrometry method for the precise measurement of isotopic abundance.

The study was recently published in Journal of the American Society for Mass Spectrometry.

Stable and long-lived isotopes, which are widely present in nature, serve as important natural tracers for studying astrophysical elemental abundances, archaeological chronology, and environmental processes in the atmosphere, hydrosphere, and pedosphere. Currently, the recommended values for isotopic abundances are derived from extensive experimental data accumulated over nearly a century, which are published by the International Union of Pure and Applied Chemistry (IUPAC) and the International Atomic Energy Agency (IAEA).

Traditional techniques, including accelerator mass spectrometry, nuclear magnetic resonance, and various commercial high-precision mass spectrometry methods, are generally constrained by systematic errors that are difficult to eliminate entirely. These errors stem from complex instrumental responses, challenges in sample preparation, and unavoidable background contamination.

To address these challenges, the research team introduced a new approach based on the fundamental mechanism of molecular Coulomb explosion fragmentation. Using carbon monoxide molecules as a test case, they achieved highly accurate measurements of the natural abundances of carbon-13 and oxygen-18.

Experimental results indicate that this method effectively eliminates systematic errors, enables clear discrimination between different isotopes, and achieves an accuracy of better than 0.02%. This represents a significant leap in the reliability of isotopic abundance measurements.

The study provides a new experimental method for obtaining high-precision, traceable elemental abundance data. The researchers noted that this two-dimensional mass spectrometry method is expected to have broad application prospects in fields such as nuclear astrophysics, paleoclimate reconstruction, archaeology, and environmental tracing.