Influence of interelement effects on x‐ray fluorescence calibration curve coefficients for binary mixtures

It has been shown that x‐ray fluorescence calibration curve coefficients are closely related to matrix effects, such as absorption or absorption plus enhancement of the fluorescent radiation. In the classical paper of Rasberry and Heinrich, 1 a single coefficient (named A ik ) calibration curve was proposed when pure absorption is the predominant effect on the spectral line of interest. Similarly, and for practical purposes, a single coefficient (named B ik ) was also considered when absorption and enhancement are present. We propose a new interpretation of calibration curve coefficients based on analytical expressions obtained recently for binary compounds under monochromatic excitation. Six distinct possible cases of calibration curves arise. Examples of binary compounds for each case are given. The data considered have been computed using the fundamental parameters method which allowed us to study a large number of possible mixtures for an arbitrary monochromatic excitation. Finally, through a different approach we discuss how this analysis could be extended to consider polychromatic excitation.