ICP-AES of zirconium and zirconium alloys using aerosol cyclone with low voltage spark discharge

The solid analysis of zirconium and zirconium alloys (Sn, Ni, Fe, Cr, Nb, Mo, W, Co, Si, Mn, Hf, Cu, Ti) by ICP-AES has been investigated. An aerosol generator by a low voltage spark discharge was used for vaporization of metal samples, and the aerosol was introduced into a plasma through an aerosol cyclone. Under the operating conditions for the analysis of steel samples, it was impossible to determine Hf, Mo and W in zirconium and zircaloy samples (NBS SRMs 1234 ∼ 1239, JAERI Z-1 ∼ Z-8, Z-11 ∼ Z-14). The background intensities were measured by varying the total argon flow rate in the aerosol generator from 0 to 15 l/min, so that they rapidly decreased with the increase of the argon flow rate. This phenomenon was considered to be due to the fact that the plasma temperature had lowered with the increase of the gas flow rate. Next, while introducing an aerosol into a plasma, the spectral intensities of each elements were measured by varying the total argon flow rate in the aerosol generator from 2.5 to 15 l/min, so that they also decreased with the increase of the argon flow rate. This fact means that the fall of excitation efficiency is due to the two causes, that is, the drop of the plasma temperature and the decrease of the staying time of sample particles in the plasma with the increase of the argon flow rate. The determinations of Hf, Mo and W were impossible by using 8, 11 and 13 l/min of total argon flow rates (carrier gas: 2.5 l/min), while these elements could be determined at 5 l/min of the total argon flow rate. The relative standard deviation of analytical values of most elements was better by the proposed method than by the conventional low voltage spark emission spectrometry and the working curves for the former were all straight. (author)