SOLID SAMPLING ELECTROTHERMAL VAPORIZATION INDUCTIVELY COUPLED PLASMA ATOMIC EMISSION-SPECTROMETRY (ETV-ICP-AES) - INFLUENCE OF SOME ICP OPERATING PARAMETERS

Some parameters of solid sampling electrothermal vaporization inductively coupled plasma atomic emission spectrometry (SS-ETV-ICP-AES) were investigated. The study concentrates gn the determination of Cu, Cd and Pb. Observation height and carrier gas flow rate were optimized for different materials. Observation heights were found to be only slightly influenced by the matrix, which however, has a large impact on the optimal carrier gas flow rate. Radio frequency (rf) power has little influence on the signal, but for a higher forward power, the plasma will tolerate a higher matrix loading. The transport relative efficiencies for pneumatic nebulization, liquid-ETV (solution-ETV) and solid sample ETV (SS-ETV) for different solid materials were compared. In the case of Cd, the transport efficiency for ETV-ICP-AES was found to be about 10-30 times higher than with pneumatic nebulization whereas for Cu only, a factor of 4 and for Pb a factor of 10 was observed. Between solution-ETV and SS-ETV no significant difference was found for the transport efficiencies of Cu and Pb for different matrices, while the efficiency of the Cd transport turned out to be highly matrix-dependent.