Effects of Matrix Elements on the Analyte Emission Signals in Inductively Coupled Plasma Optical Emission Spectrometry Using a Thermospray Sample Introduction System

Abstract

Matrix effects due to Ca, K, Na, and P on analyte transport rate, line intensities, and plasma excitation conditions were studied using a fused silica capillary thermospray nebulizer. Several emission lines of Ba, Cd, Co, Cr, Cu, Mg, Mn, Ni, Pb, and Zn, differing in their excitation and ionization energies, were investigated. In general, the addition of matrix elements to the analyte solution resulted in a reduction of the analyte emission signal. The greatest reductions were observed for matrices containing calcium and for the analyte emission lines with higher sum of excitation and ionization energies. A decrease in the analyte transport rate was the highest for single potassium matrix and for binary matrices containing calcium. The excitation temperature was not significantly changed in the presence of Na, K, and P, but it was depressed for single and composite matrices containing Ca. It was shown that variations in the analyte emission intensities in the presence of concomitants could be attributed to changes in the plasma as well as to changes in the analyte transport efficiency.