Basic characteristics of negative ions observed in ICP-MS have been evaluated and compared with those reported for positive ions. The types of ion species, ion sensitivities, background ions, and ion energies suggest that the negative ions observed in this study do not originate directly from the plasma but rather from electron capture or reaction downstream of the free jet expansion.
VaughanM. A. and HorlickG., Appl. Spectrosc.40, 434 (1986).
2.
DouglasD. J.RosenblattG.QuanE. S. K., and FrenchJ. B., Proceedings of the 6th International Symposium on Plasma Chemistry, BoulosM. I. and MunzR. J., Eds. (IUPAC, 1983).
3.
VickersG. H.WilsonD. A., and HieftjeG. M., Federation of Analytical Chemistry and Spectroscopy Societies (1986), Paper 192.
4.
FulfordJ. E. and DouglasD. J., Appl. Spectrosc.40, 971 (1986).
5.
HorlickG.TanS. H.VaughanM. A., and RoseC. A., Spectrochim. Acta, 40B, 1555 (1985).
