Surface contamination can be minimized by cleaning the surface of the sample. Care should be used, though, if acetone or alcohol is applied to the surface. Both have been shown to dissolve and smear epoxy mounts across the surface of a sample. Just water and a soft cloth work very well for cleaning sample surfaces. If more aggressive cleaning is required, then repolishing the surface should be undertaken with a very fine polish.
The effects of surface contamination can also be minimized by using a higher acceleration voltage, which produces a greater depth penetration. Therefore the percentage of the interaction volume that will be contained in the surface film will be much smaller and, as a result, the film will have less of an effect on the analyses. The downside of using a higher accelerating voltage is that the interaction volume will be larger and therefore the analysis will be sampling a larger area.
Another strategy for minimizing the effects of surface contamination and hydrocarbons in the vacuum is to use a calibration curve for the analyses. The advantage of a calibration curve is that the contamination problems
mentioned above will be the same for both the standards and unknowns, and therefore will be eliminated. However, calibration curves can only be used when the standards
and unknowns have a similar composition, and therefore the matrix effects will be the same.