Developments and technological advancements characterize the modern world. The changes increase the ability to understand, control, and analyze different aspects. One of the fields that have much development is analytical instrumentation. And in particular, the Time of flight secondary ion mass spectroscopy (ToF-SIMS).
What is Tof-SIMS?
ToF-SIMS Analysis is a surface-sensitive analytical method. It uses a pulsed ion beam to remove molecules from the outermost surface of your sample. The specific particles are removed from atomic monolayers on the secondary ions. Then, the particles are accelerated into a flight tube to determine their mass by measuring the exact time they reach the detector.
There are three operation modes for ToF-SIMS analyses, surface spectroscopy, surface imaging and depth proofing. It has analytical capabilities such as:
- Retrospective analysis: a pixel of the ToF-SIMS map represents a complete mass spectrum. It allows you to produce maps for the mass of interest retrospectively and interrogate your regions of interest for chemical composition.
- Sub-micron imaging to map every mass number of interest
- Tracing element detection limits in the ppm range
ToF-SIMS instruments include:
- An ultrahigh vacuum system. It is essential to increase the mean free path of ions in the flight path
- A particle gun which uses Ga of Cs source
- The flight path can be circular in design, which uses electrostatic analyzers to direct particle beams, or linear design, which uses a reflecting mirror.
- The mass detector system
The instruments have powerful computers and software for system control and analysis. The software can perform retrospective analysis, meaning all molecules from the sample detected by the system can be stored as a function of the mass and its point of origin by the computer.
Typical applications of ToF-SIMS analysis.
- Isotopes of elements
ToF-SIMS helps in identifying isotopes of elements and molecules. Identifying the isotope distribution pattern is a valuable characteristic that helps identify elements and molecule fragments. Mass spectrometry helps show the isotope’s natural abundance if the sample is not enriched.
- Ion mass spectrometry of silicone
Silicones are popular in the plastic industry and paint business. Silicone is a release agent in the plastic industry and a wetting agent in the paint industry. It, therefore, is a contaminant on the surface of various objects.
It fails adhesion and causes paint defects to its low surface energy nature. Also, traces of silicone can migrate to the surface and cause surface contamination. ToF-SIMS analysis helps to determine silicone contaminations as they have high surface and chemical sensitivity.
- Paint craters
ToF-SIMS analysis is essential for exploring the localization of chemicals. It’s helpful in circumstances where the presence of a chemical is critical but is overlooked due to the weakness of its ions. Paint craters are a perfect example which might result from fluorocarbon particles, fatty acids or silicone due to their low surface energy. ToF-SIMS analysis helps to study the cause of paint craters.
- Depth Profiling
ToF-SIMS techniques help in profiling organic and inorganic substances using an ion beam. It involves sputtering a surface for a certain period. Then evaluate the newly produced surface within the sputtered surface to get a data point in-depth profile.
Final thoughts
ToF-SIMS is vital in expanding the ability to meet the demands of current and future analytical solutions. It’s a surface-sensitive technique with applications ranging from automotive, electronics, metals, and life science. Knowing its meaning and how it works will help you apply the technique better.
