Selective ion-cyclotron-resonance acceleration of individual K, Ne, Cl, A, and Xe isotopes has been observed in plasmas of density 109 to 1011 cm^-3. Energy discriminating probes show good resolution of accelerated species in all cases. Mass spectrometer analyses of potassium samples, collected on cooled tungsten ribbons, showed 41K to 39K abundance ratios of 4 rather than the normal value of 0.07
