Abstract
A new method by DC arc excitation in a slow oxygen stream have been developed.A sample, after it is dispersed in or mixed with pure graphite powder and loaded in the hole of graphite electrode, is-excited in 3-5A dc arc in oxygen, streaming slowly from the lower end of a quartz cylinder to upward.With this method, dissipation of the electrode and powder is quickened, CN band is much reduced and burnt residue is carried out from inside of the cylinder.Consequently, the total burning time is much shortened, the selective volatilization can be ignored and photometry in the near ultraviolet region becomes possible.However, other kinds of matrix effect are emphasized.
In comparison with the spark method, quality of the spectra in this method is so fine that sensitivity in photometric procedure is higher than Cu-spark technique for many elements.Some characteristics of the new method are demonstrated
