EPR IMAGING IN BIOLOGICAL APPLICATIONS - TOWARDS MICROTOMOGRAPHY

EPR imaging and microtomography promises to be a powerful tool for the EPR spectroscopist, but the expansion of this technique was hindered by the lack of commercial apparatus, A simple modification of an exist ing commercial system that can reach a resolution of the order of 75 m u m with a gradient of 150 mT m(-1) is described, This resolution can be increased by using larger field gradients, In many biological appli cations this resolution is significant, As an example, the distributio n of a paramagnetic probe in in amphibious egg cell is presented that permits one to distinguish the nucleus of the ed. A summary of the mat hematical techniques which enable one to account for the presence of a hyperfine structure in most EPR paramagnetic probes and to increase r esolution is also presented.