ToF-SIMS at a glance
Time of Flight Secondary Ion Mass Spectrometry (ToF-SIMS) is a highly sensitive analytical technique that describes the chemical composition and distribution of a sample surface. It uses a range of incident ion sources to impact on solid surfaces and generate secondary ions that can be analysed by a time of flight (or Orbitrap) mass spectrometer to determine the surface chemistry of that surface or layer.
- Surface Spectrometry
- Surface Chemical Imaging
- Depth Profiling
How does ToF-SIMS work?
ToF-SIMS uses a pulsed primary ion beam (Bin+, Cs+, Ar+, etc.) to impact on a sample surface and induce a fragmentation cascade. The result is the desorption of neutrals, secondary ions (+/-) and electrons from the first few monolayers of the sample. The secondary ions can then be accelerated into a "flight tube" and their mass is determined by measuring the exact time at which they reach the detector (i.e. time-of-flight).
A single secondary ion mass spectrum can be used to describe the constituents of one point on a surface. Alternatively if the incident beam is rastered across several points within a given surface area, it is possible to build a chemical image map of that surface. Using incident ions such as Cs+, Arn+ C60+ in a dual beam approach it is also possible to sputter through the top layers of the inorganic or organic surfaces respectively while monitoring the incidence profile of elemental or molecular species (i.e. depth profiling).
Our ToF-SIMS facilities
ION-TOF (GmBH) ToF SIMS IV
- Liquid metal (Bin+n) ion gun (LMIG) for spectroscopy and imaging at a spatial resolution of ~ 1 µm.
- Argon gas cluster source for the high resolution depth profiling of organic materials (polymers and biological samples) and 3D chemical characterisation.
- Sensitivity down to ppm (femtomole).
- A 5-axis multi-sample stage is fully automated and provides rotation for high resolution (nm) depth profiling (Cs+ or C60+ sources).
- Reflectron ToF mass analyser gives mass resolution > 7000 at m/z = 29.
- Image surface areas from the µm to cm scale.
- 3-D elemental mapping possible.
- Wide range of samples accepted including conductors, semi-conductors and insulators.
- Powders, foils, biological materials etc.
- Sample size ranging from a few mm up to ~ 10 cm.
- Sample temperature management with cooling to -100°C and heating to 600°C
ION-TOF (GmBH) Hybrid SIMS ("3D-OrbiSIMS")
- Hybrid SIMS system combining ToF-SIMS with an Orbitrap mass spectrometer.
- The first of its kind in an academic setting the instrument combines the function of the two hybridised components to facilitate an unprecedented level of mass spectral molecular analysis for a range of materials (hard and soft matter, biological cells and tissues).
- The dual functionality underpins spatial and mass resolution improvements in chemical identification and imaging.
- Allows state-of-the-art ToF-SIMS using the ToF V chassis independent or in combination with unparalleled mass resolution from the Orbitrap detector.
- Ideal for identifying and mapping unknown organic species in complex solid samples (tissues, cells etc.)
- High mass resolution spectrometry (>240,000 and 11,000 amu for the OrbiTrap and the ToF, respectively).
- High spatial resolution chemical imaging (<70 nm).
- Cryogenic sample preparation facility, including high pressure freezing, freeze drying, cryo-ultramicrotomy and cryogenic transfer system.
- Category 2 preparation facilities for cell/tissue analysis and sample transfer to correlative techniques (cryo-SEM, cryo-TEM, cryo-microscopy etc.)
Publications of interest
- Starr, N. J., Johnson, D. J., Wibawa, J., Marlow, I., Bell, M., Barrett, D. A., Scurr, D. J. (2016) Age-Related Changes to Human Stratum Corneum Lipids Detected Using Time-of-Flight Secondary Ion Mass Spectrometry Following in Vivo Sampling. Analytical Chemistry. 88 (8) 4400-4408. DOI: 10.1021/acs.analchem.5b04872
- Adler-Abramovich, L., Marco, P., Arnon, Z. A., Creasey, R. C. G., Michaels, T. C. T., Levin, A., Scurr, D. J., Roberts,C. J., Knowles, T. P. J., Tendler, Saul J. B. and Ehud Gazit, E. (2016) Controlling the Physical Dimensions of Peptide Nanotubes by Supramolecular Polymer Coassembly. ACS Nano. DOI: 10.1021/acsnano.6b01587
- Hook, A. L., Williams, P. M., Alexander, M. R., Scurr, D. J. (2015) Multivariate ToF-SIMS image analysis of polymer microarrays and protein adsorption. Biointerphases. 10. DOI: 10.1116/1.4906484
- Bailey, J., Havelund, R., Sharp, J. S., Shard, A. G., Gilmore, I. S., Alexander, M. R., and Scurr, D. J. (2015). 3D TOF-SIMS Imaging of Polymer Multi-layer Films using Argon Cluster Sputter Depth Profiling. ACS Applied Materials & Interfaces. 7. DOI: 10.1021/am507663v
- Scurr D.J., Hook A.L., Burley J., Anderson D.G., Langer R., Davies, M.C. and Alexander M.R., (2012). Strategies for MCR Image Analysis of Large Hyperspectral Data-Sets. Surface and Interface Analysis. 45(1), 466-470. DOI: 10.1002/sia.5040
- Scurr D.J., Horlacher T., Oberli M.A., Werz D.B., Kroeck L., Bufali S., Seeberger P.H., Shard A.G. and Alexander M.R. (2010) Surface characterisation of carbohydrate microarrays. Langmuir. 26 (22), 17143-17155. DOI: 10.1021/la1029933
- Scoutaris N., Hook A.L., Gellert P.R., Roberts C.J., Alexander M.R. and Scurr D.J. (2012) Tof-Sims Analysis Of Chemical Heterogeneities In Inkjet Micro-Array Printed Drug/Polymer Formulations. Journal of Materials Science. Materials In Medicine. 23(2), 385-91. DOI: 10.1007/s10856-011-4474-5