A Uniform Nonlinearity Criterion Resulting from Normalization of Nonlinear Models Applied for Calibration Curve and Standard Addition Methods

It is proved that the shape of equations obtained after transformation of real (x, y) into normalised (u, v) variables enables to present polynomial and rational functions in a unified form. In terms of normalised variables, the equations applicable for calibration curves are analogous to ones obtained for standard addition method. It enables to apply a common criterion adaptable for both methods of chemical analysis.