Influence of hydrocarbons on element detection in ion images by SIMS microscopy

Ion microscopy on fresh frozen cryostat sections, 5–10μm thick, is useful to determine the distribution of elements and low molecular organic compounds in the larger areas of the tissues. Fresh frozen cryostat sections of tree frog eyeball were examined. Secondary ion images of Na, Mg, Al, C2H3, K, Ca and C3H5 were observed by ion microscopy (IMS-6f) using O2+ as the primary beam source at an energy of 15keV. The primary beam current was 10−10A, the ion image magnification was varied from 300 to 1500 and the mass resolution was set between 300 and 3000. The areas of high intensity ion counts of the organic compounds generally showed low ion counts of elements. After long exposure to the primary ion beam, the intensity of the organic compound ions decreased, whereas the intensity of atomic ions of elements increased.