An evaluation of the use of yttrium and beryllium as internal standards in inductively coupled plasma emission spectrometry for untreated aqueous solutions in presence of high concentrations of organic solvents and matrices

Abstract

Non-spectral interferences are known to affect the robustness and precision of inductively coupled plasma-emission spectrometry (ICP-AES), especially in the case where the ICP-AES instrumentation includes conventional nebulization systems and the samples should not be pre-treated or are specially prepared as in-house working standards. Under these circumstances, yttrium ionic lines and a beryllium atomic line may be evaluated as internal standards (ISs). In this study, the working standards were prepared with the addition of several reagents that are known to affect the plasma's robustness in a set of series of multi-element standard solutions. In the applied methodology, conventional equipment (a cross-flow pneumatic nebulizer and a double-pass, Scott-type spray chamber) was used and the operating parameters of ICP-AES were adjusted to produce a robust plasma. A sum of 39 analytical lines of 19 elements (Ag, Al, B, Ba, Bi, Ca, Cd, Co, Cr, Cu, Fe, Ga, In, Mg, Mn, Ni, Pb, Tl and Zn) were studied. The studied organic substances were solvents such as dioxane and formic acid and also glucose and sucrose at various concentration levels. The overall sensitivity changes and the accuracy of the method were used as quantitative criteria to evaluate the effect of the presence of the above mentioned substances. The results are useful for the analysis of many kinds of untreated samples, as well as for the analysis of eluents from separation procedures in hyphenated ICP-AES methodologies.