Comparison of characteristics and limits of detection of pneumatic micronebulizers and a conventional nebulizer operating at low uptake rates in ICP-AES

Three micronebulizers, the high-efficiency nebulizer (HEN), the microconcentric nebulizer (MCN) and the micromist (MM), were compared with a conventional pneumatic concentric nebulizer working at low liquid flow rates in ICP-AES. The gas back-pressure, the free liquid aspiration rate, the drop size distribution of primary and tertiary aerosols, the solvent and analyte transport rates, the emission intensity and the limits of detection were measured. The solvent evaporation inside the spray chamber proved to be a very important transport phenomenon when working at very low liquid flow rates. The micronebulizers produced finer primary aerosols, higher solution transport rates through the spray chamber and higher sensitivities than the conventional pneumatic concentric nebulizer. The HEN used in this work provided slightly lower ICP-AES limits of detection than the other two micronebulizers, but at the expense of a higher back-pressure.