Behaviour of a single-bore high-pressure pneumatic nebulizer operating with alcohols in inductively coupled plasma atomic emission spectrometry

Abstract

The behaviour of a single-bore high-pressure pneumatic nebulizer (SBHPPN) with alcohols in (ICP-AES) was investigated. A standard Meinhard nebulizer was used for comparison. To this end, the drop size distribution of the primary aerosols, the analyte and solvent transport rates, W_tot and S_tot, the fraction of solvent transported in liquid and vapour forms, S_liq and S_vap, the excitation temperature of the plasma, T_exc, and the molecular emission intensity of the C₂ band were determined for solvents of different physical properties. The effect of the physical properties of the solvent on the nebulization process was also studied.

The results show that the SBHPPN gives rise, for all the solvents studied, to primary aerosols that have smaller mean diameters than those produced by the Meinhard nebulizer for the same gas and liquid flows. The relative decrease in volume median diameter (D_v,50) when switching from the Meinhard nebulizer to the SBHPPN is more noticeable for alcohols than for water. W_tot is significantly higher for the SBHPPN than for the Meinhard nebulizer, particularly at high liquid flows. However, the differences between their S_tot values are less pronounced. Under similar conditions, the SBHPPN gives rise, for all the solvents studied, to higher emission intensities than the Meinhard nebulizer. However, the relative signal enhancements achieved by changing from the SBHPPN to the Meinhard nebulizer are lower than the corresponding analyte transport enhancements. The relative signal enhancements achieved by switching from water to alcohols are lower for the SBHPPN than for the Meinhard nebulizer. This behaviour can be explained in terms of the higher S_tot values associated with the SBHPPN, which lower T_exc in comparison with the Meinhard nebulizer.