The results of measurements of the C-70 content of a C-60 single cryst
al on a standard MI-1201 mass spectrometer with an improved ion source
employing electron-impact ionization are presented. The method is sui
table for the mass-spectrometric analysis of other solid substances wi
th vapor pressures no lower than 1 x 10(-5) Pa at the temperatures up
to 800 degrees C.