Abstract
Atomic negative ions were studied for eighty one different elements by means of double focusing mass spectrograph. Over one hundred twenty different sample materials were ionized by pulsed radio-frequency vacuum spark discharge.Special features for the negative ion mass spectra were discussed and compared with positive ion mass spectra. Fourty eight the elements were detected as atomic negative ions, and the results were discussed with literature values of the electron affinity for the atoms. Chemical analysis by negative ion mass spectra was briefly discussed.