Microanalysis of individual mitochondrial granules with diameters less than 1000 angstroms.

A scanning electron microscope was converted to an electron microprobe with high spatial resolution by the addition of a transmitted electron detector and a solid-state x-ray detector. Spectra obtained from mitochondrial granules of chondrocytes in situ confirm the suspected presence of calcium and phosphorus. Contamination during analysis can lead to false indications of silicon in living tissue.