Time-of-Flight Secondary Ion Mass Spectrometry (ToF SIMS) is used to investigate the chemical makeup of solid surfaces and thin coatings. It offers a thorough, three-dimensional chemical map of the material. This includes information about the distribution of the atoms and molecules in the sample and any contamination that may be present. There are numerous uses for this kind of data.
Industrial quality control, research organizations, and academic research labs frequently employ ToF SIMS. The comprehensive chemical information that ToF SIMS offers benefits many disciplines, including analytical chemistry, geology, biology, pharmaceutical science, materials science, and many more. Below, we discuss some typical applications of TOF SIMS analysis.
ToF SIMS spectrum analysis can reveal details about the sample’s atomic or molecular composition and the overall abundance of different chemicals. In some circumstances, it is also feasible to calculate atomic ratios, although this calls for well-chosen reference materials and carefully managed samples.
Most large ToF SIMS devices use tandem mass spectrometry, which is very helpful for accurately detecting ions. Tandem mass spectrometry, sometimes called MS/MS or MS2, is a technique that separates an interesting secondary ion, breaks it up, and gathers the pieces in a mass spectrum. Identifying the parent ion with high precision is feasible by analyzing the offspring’s peaks.
For most ToF SIMS applications, 2D pictures are generated by scanning the surface with the ion beam, obtaining a mass spectrum at each pixel. A few hundred to over four million pixels can make up the image resolution.
The exact distribution of ions throughout the field of view is displayed in images of specific mass channels. The distribution of different ions and their interactions can be observed by superimposing numerous mass channels.
ToF SIMS is unique among mass spectrometry and analytical methods in that it can provide three-dimensional data sets. A 3D analysis builds up a three-dimensional image of the sample by continually capturing multiple 2D layers over the same area and etching material with each pass. Large cluster ions can be utilized to simultaneously etch and analyze the material, which makes them perfect for 3D analysis because they cause very little damage.
Depth profiling is a strong analytic mode that involves etching vertically through the sample and obtaining a mass spectrum at each layer. The outcome is an overall profile of all the atoms and molecules in the sampled volume. Large cluster ions minimize interlayer mixing and maximize depth resolution by reducing damage to subsurface layers. It is possible to achieve depth resolution as low as a few nanometers with the appropriate ion beam and sample combination.
Precise prediction of a drug’s pharmacological impact requires measurement of the drug’s concentration at the target. Consequently, a method for producing label-free sub-cellular imaging is needed since fluorescent labels can potentially change medication chemistry and outcome.
With its powerful label-free chemical imaging capabilities and high lateral resolution, ToF SIMS can resolve sub-cellular features and perform 3D analysis. ToF SIMS is thus a potentially helpful analytical method to screen for novel therapeutic molecules.
ToF SIMS has many applications, from fundamental biology to metallurgy and almost everything in between.