Analytical performance of a thermospray sample introduction system for inductively coupled plasma atomic emission spectrometry

Abstract

The operating conditions for thermospray sample introduction into the inductively coupled plasma have been optimized. The influence of the inner diameter of the vaporizer capillary in the range from 0.05 to 0.150mm was studied. The optimization procedure included the sample uptake rate, the generator power, the carrier argon flow and the observation height. The highest signal-to-background ratio (SBR) was obtained with the 0.050 mm capillary. Using the optimized conditions the detection limits for the 19 elements studied are on average improved by a factor of 3 compared to sample introduction with a V-groove nebulizer, with the exception of Ga, Fe, Cr and Al. The relative standard deviation (RSD) on analyte signals obtained with the thermospray sample introduction system is about 1.0%, whereas the long-term stability of the signal is better than 5% after stabilizing for one hour. These values are similar to the short and long-term stability obtained with a V-groove nebulizer.