The concordance of algorithms and influence coefficients for the correction for matrix effects in XRF

Abstract
The development of influence coefficient algorithms has retained the attention of XRF analysts given that their goal seeks to combine the theoretical exactness of the fundamental parameters approach for quantifying fluorescence missions and the flexibility of simple mathematical models that convert experimentally measured fluorescence intensities to concentrations. By definition, the purpose underlying the use of influence coefficients is to quantify or condense in one value the magnitude of absorption and/or enhancement effects. This presentation examines the concordance underlying a number of algorithms and their influence coefficients which have been proposed over some 50 years. Initially, influence coefficients were defined only in the context of binary absorption and monochromatic excitation sources. Subsequently, the coefficients were defined explicitly for the more comprehensive context, namely, polychromatic excitation sources, absorption and enhancement effects defined separately or combined as "matrix effects" in multi-element specimens. Thus, on close examination, it can be shown that contrary to algorithms, influence coefficients are direct explicit functions of analytical contexts and that algorithms, often contested when interpreted in the original context for which they were developed, retain their validity when subsequent advancements in the definition of influence coefficients are taken into consideration.