Going beyond the mass scale: Exploiting state-of-the-art instrumentation to add molecular structure to 3D mass spectrometry imaging

The Surrey Group have been active in secondary ion mass spectrometry (SIMS) for over thirty years using the method to unravel the complexities of interface chemistry in adhesive bonds, organic coatings on metals and fibre composite materials. During this time, the Group has collaborated extensively with industry and academia and introduced a number of novel approaches in time-of-flight SIMS (ToF-SIMS) eg methods for discrimination of similar polymeric materials in a coil coating (https//doi.org/10.1021/acs.analchem.7b04877).

NPL and collaborators pioneered the revolutionary OrbiSIMS instrument. The instrument has the ability to provide 3D imaging with high mass-resolving power and a depth resolution of less than 10 nm and has proven popular in a broad field of applications from organic electronics to drug discovery. Recently, NPL and collaborators published a study of key OrbiSIMS parameters and indicated the possibility for separation of molecules based on their shape, stability and kinetics of formation.

Initial results indicate that in this manner it is possible to probe secondary features of materials, such as isomerism in polymers; this is an important observation as it takes SIMS from a surface chemical analysis technique to one which has the ability to provide structural information; going beyond the mass scale.

This project aims to understand the physics behind the phenomena that separates molecules by structure and leverage these to develop innovative methods to study molecules at the micro and nanoscale. Reference metal materials will be used for fundamental studies and structural isomers organic molecules will be used for the development of analytical methods.

The fundamental studies will be aided by computer simulation of ion paths. The project will make use of two SIMS systems, the standard ToF-SIMS at Surrey and the OrbiSIMS at NPL. The geographical proximity of the two sites will enable ready travel between the two