The role of the nebulizer on the sodium interferent effects in inductively coupled plasma atomic emission spectrometry

Abstract

The role of the nebulizer on the sodium chloride interferent effects in ICP-AES was investigated. Three different pneumatic nebulizers coupled to a cyclonic spray chamber were investigated: a V-groove (VGN) and two new pneumatic concentric nebulizers specifically designed to work with saline solutions (the 'Seaspray' nebulizer, SSN, and experimental nebulizer, EN). The effect of the salt concentration on the characteristics of the aerosols generated by the nebulizers (primary aerosols) and those at the exit of the spray chamber (tertiary aerosols) on the transport parameters and on the analytical figures of merit in ICP-AES were evaluated. The characteristics of the primary aerosols were related to their critical dimensions and were independent of the solution salt concentration. Solvent and analyte transport rates were related to the characteristics of the primary aerosols. Thus, the SSN provided the highest solution transport rates followed by the EN and VGN. The Mn II emission signal correlated quite well with transport parameters. When the salt concentration increased, an interference effect on the ICP-AES emission signal was observed. This effect was related to the nebulizer employed. Thus, for the SSN, the effect of the sodium chloride on the emission signal was different for the ionic and atomic lines. For the remaining nebulizers, a depressive effect of the salt concentration on the emission signal was always observed irrespective of the line considered. The magnitude of the interference was different for each nebulizer and was related to the amount of solvent transported to the plasma. In general terms, by increasing the salt concentration, poorer signal precision and limits of detection were obtained. These results confirm the importance of sustaining robust plasma conditions to reduce the sodium chloride interferences.

Liquid-sample introduction in plasma spectrometry

“…Most of them are of the cross-£ow type (based either on the Babington principle, such as the V-groove (VGN), the cone-spray, the Hildebrand grid nebulizers, etc.) or based on modi¢cations of the conventional PCNs [8].…”

A Novel Nebulizer‐Based Continuous Flow Reactor: Introducing the Use of Pneumatically Generated Aerosols for Highly Productive Photooxidations

“…One of the most important characteristics of the pneumatic nebulizer is its ability to produce aerosols consisting of fine droplets. This particular nebulizer when operated with argon gas and water‐based solutions has been reported to provide droplets with an average diameter of approximately 6 μm, referred to as the Sauter mean diameter ( D 3,2 ) which is defined as the diameter of a sphere that has the same volume/surface‐area ratio as the particle/droplet of interest . However, due to differences in the solvent used (methanol is mainly used in the present study), the nebulizing gas (herein, oxygen or air) and the different solution uptake and gas flow rates, the produced droplet size is expected to vary to some extent from the aforementioned value.…”

“…This particularn ebulizer when operated with argon gas andw ater-based solutionsh as been reported to provide droplets with an averaged iameter of approximately 6 mm, referred to as the Sauter mean diameter (D 3,2 )w hich is defined as the diameter of as pheret hat has the same volume/surface-area ratio as the particle/droplet of interest. [30] However,d ue to differences in the solvent used (methanol is mainly used in the present study), the nebulizing gas (herein, oxygen or air) and the different solution uptake and gas flow rates, the produced droplets ize is expected to vary to some extentf rom the aforementioned value. Despite being difficult to predict the exact effect on the average dropletd iameter, we have adoptedt hree droplet-size scenarios and calculated the droplet surface area for each one of these options for comparison purposes.…”

Design and evaluation of an improved microwave-based thermal nebulizer for liquid sample introduction in inductively coupled plasma atomic emission spectrometry

“…However, if a PN is employed, aerosol characteristics and analyte transport rates are less influenced by Q l and sample composition. 39 Thus, D 50 increases by 10% with the PN when Q l is increased from 0.9 to 1.8 mL min À1 for 1% w/w nitric acid solution.…”