Abstract

In the present work, the matrix effects observed in ICP-AES with both nitric- and sodium-based solutions have been discussed. Some approaches previously proposed in the literature to mitigate the matrix effects (i.e., the use of a cyclonic spray chamber and the proper selection of plasma conditions) have been adopted in the present study. Therefore, the magnitude of matrix effects observed throughout was rather low. A conventional pneumatic concentric nebulizer operated at 1.9 ml min⁻¹ was first employed. Then the solution uptake rate, Q_l, was reduced by a factor of around 10 to 40 (i.e., 0.15 and 0.05 ml min⁻¹). A micronebulizer (i.e., high efficiency nebulizer, HEN) was employed to handle these low flow rates. The results indicated that, when working at very low Q_l and for some lines, the matrix effects became more severe than at conventional liquid flow rates (i.e., of the order of 1–2 ml min⁻¹). This fact appeared to reveal that the plasma solvent vapor load caused a detrimental effect from the point of view of inorganic matrix effects. The data corresponding to sensitivity and signal stability indicated that the use of robust plasma conditions did not deteriorate any of these analytical figures of merit.