Effect of Matrix Element and Acid on Analytical Signals in Nitrogen Microwave-Plasma Atomic Emission Spectrometry

The effect of matrix elements (Na, In, Bi, Zn, Cu) and nitric and hydrochloric acids on the analytical signals of impurity elements in nitrogen microwave-plasma atomic emission spectrometry (MP AES) was studied. In the range of acid concentrations 0.1–0.5 M (for rare-earth elements, 0.1–0.9 M), the analytical signals of the elements did not change. The presence of a matrix element in a concentration of 1 wt % led to a significant change in the signal for most elements, which must be taken into account in selecting a calibration strategy. In MP AES, it is necessary to fully comply with the conformity of samples and calibration solutions regarding the type and concentration of acid and matrix elements.