Aerosol desolvation studies with a thermospray nebulizer coupled to inductively coupled plasma atomic emission spectrometry

Abstract

Two desolvation systems commonly used in ICP-AES have been evaluated when coupled to a thermospray nebulizer. The desolvation systems are: (i) a thermostated spray chamber (TSC) and, (ii) a two-unit desolvation system (TUDS) in which the first unit is a heated single-pass spray chamber and the second one is a Liebig condenser. Both systems were evaluated with aqueous and organic solutions. The temperature of the chamber in the TSC (25 to 20 °C) and the temperatures of the heated spray chamber (60 to 140 °C) and the condenser (25 to 20 °C) in the TUDS were taken as variables. To evaluate the effect of these variables on the performance of the desolvation systems, drop size distribution of the tertiary aerosol, solvent and analyte transport rates and emission signal have been measured. Under optimal desolvation conditions, the values of the solvent transport efficiencies were similar for both systems, ranging from 2.3 to 9.5%. Analyte transport efficiency values ranged from 36 to 77% and from 5 to 8% for TUDS and TSC, respectively. TUDS gives rise to higher signals (6 to 7 fold higher) and lower LOD (2 to 11 times lower) than TSC. As regards the solvent nature, the highest emission intensity and lower LOD are obtained with ethanol, followed by water and butan-1-ol. The LOD values obtained with the combination thermospray-TUDS are 2 to 26 times lower than those obtained with a conventional pneumatic nebulizer coupled to the same desolvation system.

Carbon-related matrix effects in inductively coupled plasma atomic emission spectrometry

“…Nonetheless, also the solvent load into the plasma is increased and the plasma excitation conditions may be deteriorated and, therefore, a reduction in the expected signal can also be observed [6]. The deleterious effect of organic solvents on the plasma excitation/ionization capabilities can be minimized by appropriate selection of the experimental conditions and sample introduction characteristics [7][8][9][10][11][12][13][14]. Hu et al [15] observed that in ICP-MS, the enhancement or suppression of the analyte signals due to the presence of organic solvents depends, in addition to the solvent nature, sample introduction system and operating conditions, on: (i) the ion mass.…”

Introduction of organic solvent solutions into inductively coupled plasma-atomic emission spectrometry using a microwave assisted sample introduction system

“…); 16,17 (ii) addition of oxygen and/or nitrogen to the nebulizer and outer gas flows; 16,[18][19][20] (iii) use of low-flow sample introduction systems, 18,19,[21][22][23] cooled spray chambers 24,25 and/or desolvation systems. 13,15,[26][27][28] A microwave-based desolvation system (MWDS) for use in ICP-based techniques has been developed by our research group. 29 This device has been successfully applied to the analysis of aqueous and acid solutions both in ICP-AES 29,30 and ICP mass spectrometry (ICP-MS).…”

A microwave assisted desolvation system based on the use of a TM010 cavity for inductively coupled plasma based analytical techniques

“…In the first case only solvent load reduction is possible, whereas when using two-step desolvation systems the analyte transport rate is also increased. 1 Different heat sources have been employed for aerosol vaporization. Among them, the most common is to keep the walls of the spray chamber at high temperature (a few degrees over solvent boiling point) by means of a heating tape wound around it.…”

“…The different behaviour observed for W tot and the estimated plasma solvent load when increasing Q l can be explained bearing in mind that the solvent transport rate, and hence the plasma solvent load, increases to a lesser extent than W tot does when using desolvation systems. 1,21 The parameters employed reflect correctly the behavior of S tot when comparing introduction systems, but they do not have enough sensitivity for reflecting the small changes produced in S tot when increasing the solvent uptake rate in a desolvation system.…”