Microcalorimetric and spectropolarimetric titrations were used to investigate micellization of cationic surfactants and binding of netropsin to dodecameric DNA duplex. For description of both processes, model functions containing linear and non-linear parameters were derived. Model analysis was based on a weighted (multi)linear regression and a standard »Simplex« procedure. Close investigation of the interplay of adjustable parameters has shown that a proper choice of the model function can significantly reduce the correlations between parameters. Values of physical properties (enthalpy changes, apparent equilibrium constants...) obtained from such curve modeling are in very good agreement with the corresponding values obtained by other methods. Equations and the calculation procedure reported here could be easily generalized and used for the description of some other concentration dependent properties in similar systems
