Carbon-related matrix effects in ICP-AES

Abstract

The aim of this work is to study the carbon related non-spectroscopic matrix effects in ICP-AES. To this end, the effect of some experimental conditions (matrix nature, sample uptake rate, r.f. plasma power and sample introduction system) on the behaviour of a total of 15 elements and several emission lines covering a wide range of energy values (atomic and ionic) in ICP-AES has been studied. Results show a clear effect related to the amount of carbon present in the plasma. Thus, the presence of carbon in the plasma gives rise to a decrease in most of the emission lines tested, with the exception of As and Se. For these elements, the emission signal increases when an increasing the amount of carbon is reaching the plasma. Depending on the experimental conditions employed, the emission signals for As and Se are up to 25% higher than those obtained with pure aqueous solutions. These findings have been applied to the analysis of a certified sample of Se-enriched yeast (SELM-1).