Ambient Pressure Mass Spectrometry at the Sub Micron Scale

This proposal aims to develop a new ambient pressure mass spectrometry imaging system. It will use a beam of ions accelerated to MeV potential energy - velocities of the order of 5% the speed of light or less. The beam will be focussed using a set of quadrapole magnetic lenses to less than a micron in size and will be passed out of the vacuum system through a 100nm thick silicon nitride window into air where it will be able to travel between 0.5-1.0cm before stopping. A sample placed in front of this beam of ions will be sputtered (eroded) by the interaction of the ions with the electrons in the system (electronic energy loss). Previous experiments in vacuum have demonstrated that if the sample is a molecular material it is possible to extract large (~45kDa) molecular species from the surface and that these can be detected in a Time of Flight mass spectrometer to determine their molecular mass. Fragments that are removed at the same time give indications about the bonding arrangements of the molecules sputtered and can be used to determine the probable molecular arrangement.
The beam itself can be raster scanned using an electrostatic field so that a molecular map of the surface of the material can be determined at the micron scale. The ions as they enter the surface of the material are moving fast enough that they will also cause electrons in the outer shells of the atoms that they pass to become exited and in relaxing back will give out a characteristic X-ray. These X-rays can also be collected and analysed using a technique known as Partical Induced X-ray Emmision (PIXE) to give trace element maps as well.
This will be the worlds first scanning mass spectrometer capable of imaging at the sub micron scale in air.
Applications for this equipment range from forensics to biomedicine taking in geology and the environment as well as helping to understand the origins and manufacture of art and archeological remains. These applications will be encouraged over the period of the project.

This application is to construct the worlds first scanning ambient pressure secondary ion mass spectrometry system with sub micron resolution. It has impact across a number of disciplines of which we have identified 4 key areas to target during the grant period. These are forensics science, biomedicine, archaeometry and geology and the environment.

The initial impact will be to the accademic researchers who will be able to gain access to the equipment many of which have submitted letters of support with this application. The companies supplying the equipment required to manufacture this instrument are UK based and will be in a good position to exploit an expected market in new instruments like these. The market wil not be huge, maybe 10 or 20 such machines.

The subsequent impact of the research that this equiment will enable is potentially huge:
Informing pharmeceutical companies and the NHS on precisely how drugs are reacting with living systems such as cells. This will allow drugs to be designed with more precision and understanding so that side-effects may be minimised and the primary aim maximised. A number of cancer related drugs and activities have been highlighted as of interest to the Addenbrooke's Hospital in Cambridge as part of an on-going collaboration.
Work in forensics science aimed at extracting more information from fingerprints - with in air analysis this could even be performed covertly - has impact in helping to identify criminals even with only smudged prints. Other aspects of forensic science include providing quartz grain analysis for identification of soils which will provide substantial support for the current texture analysis. The analysis of gun shot residues for organic species will help identify new non-lead bearing ammunition residues.
Molecular analysis of parchments can only really be done in air - it is not normally considered acceptable to takes samples from ancient relics or, often, to place them in a vacuum system. The molecular analysis of the parchment material can yield surprising information about the origins of the material and, as the parchment is often orgainc in nature and the product often of an agricultural community, can reveal aspect of community life. Other aspects here include anlysis of paint binders for provenancing, normally the trace element ratios are employed, but the binders are again often natural organic materials which may well be more informative about origins than just the trace elements.
The Goeology and Environment has impact in studies of small inclusions locked up for thousands of years in geological samples. The information in these inclusions can reveal past climate and atmospheric changes on a geological scale. The environmental issues relating to bioremediation and airborne particulates have high potential impact in both providing a method to clean up polluted sites and one for monitoring airborne pollution.