Thermal ionization mass spectrometry
Thermal ionization mass spectrometry (TIMS) is a highly sensitive isotope mass spectrometry characterization technique that exploits the thermal ionization effect, in which a chemically purified sample is heated to cause ionization of the atoms of the sample. The ions are focused into a beam by electrostatic lenses, then separated into individual beams based on the mass/charge ratio of the ions by an electromagnet. TIMS is a magnetic sector mass spectrometry technique in which ions are separated as a function of their charge and velocity or mass in a magnetic field. Variants of this technique are ID-TIMS (ID = Isotope Dilution) and CA-TIMS (CA = Chemical Abrasion).
The relative abundances of different isotopes are then used to describe the chemical fractionation of different isotopes, travel in different reservoirs of non-radiogenic isotopes, and age or origins of solar system objects by the presence of radiogenic daughter isotopes.
Elemental analysis is a predominant application of TIMS as it gives reliable isotopic ratios. Following the trend of decreasing ionization energy, elements located towards the bottom left of the periodic table are viable for TIMS. In addition, the high electron affinity seen towards the upper right of the periodic table makes these nonmetals excellent candidates. The technique is used extensively in isotope geochemistry, geochronology, and in cosmochemistry.
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- Chhabil., Dass, (2007). Fundamentals of contemporary mass spectrometry. Hoboken, N.J.: Wiley-Interscience. p. 264. ISBN 9780471682295. OCLC 71189726.