Elemental analysis of frog outer segment and fuscin granule by means of x-ray microanalyzer.

Elemental analysis was made on the rod outer segments and fuscin granules in the frog eye by means of an energy-dispersive X-ray spectrometer combined with an electron microscope. The materials were prepared from the unfixed fresh retina by means of air-dried or freeze-dried cryosection, freeze-substitution, or the freeze-drying embedding method. An outer segment in the air-dried cryosection showed P, K, S, Cl, and Ca peaks. The dry section of freeze-substituted or freeze-dried embedded outer segment showed P, K, S, and Cl; K was lost in the wet section. The fuscin granules showed prominent peaks of Ca and Zn constantly, in addition to S, Cl, Mg, K, and occasionally Cu. The K peak was also lost in the wet section.