Self-matrix effects as a cause of calibration curvature in inductively coupled plasma atomic emission spectrometry

Abstract

A new cause of calibration curvature in inductively coupled plasma atomic emission spectrometry is proposed, the self-matrix effect. For a series of calcium lines, the progressive decrease in sensitivity with increasing calcium is shown to be similar to that of a number of concomitant trace element lines indergoing a matrix effect. The magnitude of the effect depends on the excitation energy of the line, for both calcium and trace element lines. These observations are consistent with a fall in excitation temperature as a common cause. An empirically derived functional relationship gave a good fit to the calibration data of the calcium lines.