TIMS

TIMS is an acronym used in multiple scientific and technical contexts. In analytical chemistry and related fields, TIMS most commonly refers to Thermal Ionization Mass Spectrometry and Trapped Ion Mobility Spectrometry, though the term can appear in other domains as well. This article outlines the two principal scientific meanings.

Thermal Ionization Mass Spectrometry (TIMS) is an instrumental method for measuring isotope ratios with high precision. In TIMS, a sample is placed on a refractory filament and heated to produce ions thermally. The resulting ions are introduced into a mass spectrometer, typically a magnetic sector instrument, where their masses are separated and detected. TIMS is especially valued for precise isotope measurements in geochemistry, archaeology, and environmental science, with applications in dating and provenance studies (for example, strontium, neodymium, and lead isotopes). Detectors often employ Faraday cups for stable, high-precision current measurements. Advantages include high isotope precision and robustness for certain elements; limitations include substantial sample preparation, potential matrix effects, and the need for careful cleanliness and calibration.

Trapped Ion Mobility Spectrometry (TIMS) is a technique that separates ions by mobility in a gas under the influence of an electric field, with ions trapped and released by ramping the field. TIMS can be coupled to mass spectrometry (TIMS-MS) to provide an additional dimension of separation based on collision cross section and mass-to-charge ratio. It is used in proteomics, metabolomics, and small-molecule analysis, offering high resolving power in a compact instrument. Trade-offs include historically slower scan rates relative to some other mobility methods, though advances continue to improve throughput.

In practice, TIMS usually requires context to distinguish which technique is intended.