Standards for measuring spatial resolution in biological X-ray microanalysis.

Lateral resolution in biological X-ray microanalysis is usually severely limited by the necessity to obtain an adequate number of X-ray counts, which requires the use of a relatively large electron beam spot size. Resolution is further degraded by spreading of the beam within the specimen. Although it is possible to make theoretical calculations of resolution, no straightforward and general method of measuring lateral resolution in biological X-ray microanalysis appears to have been proposed hitherto. In this paper, standards are proposed consisting of distinctive protein-bound elements embedded in araldite, and their use is described.