Thermal ionization mass spectrometry is a highly sensitive isotope mass spectrometry characterization technique and is used to identify isotopic ratios of inorganic and organic materials. The atoms of a chemically purified material are ionized thermally and can be separated into individual beams by an electromagnet and further detected by a mass spectrometer.

This work is in progress at the NERC Isotope Geosciences Laboratory, British Geological Survey, Keyworth, Nottingham, UK.