LASER-EXCITED FLUORESCENCE STUDIES OF MATRIX-INDUCED ERRORS IN INDUCTIVELY COUPLED PLASMA SPECTROMETRY - IMPLICATIONS FOR ICP-MASS SPECTROMETRY

Laser-induced Sr ion fluorescence measurements were made as a function of nebulizer gas flow rate and applied power in the presence and absence of concomitant species for comparison to previously published ICP-MS data. The fluorescence data are used to assess the contribution of matrix effects in the plasma itself to errors observed in ICP-MS due to the presence of concomitant species. Significant matrix effects do appear to originate in the plasma. Reconsideration of ambipolar diffusion shows that the matrix effects in the plasma should not be dependent on the mass of the analyte or concomitant species. Experimental, radially resolved measurements confirm the lack of mass dependence.