Application of the calibration surfaces method in quantitative analysis of water — ethanol — methanol mixture

Abstract

Abstract The simple and quick calibration surfaces method has been applied to the quantitative analysis of water — ethanol — methanol mixtures. The refractive index, viscosity, boiling point, density, and position of the absorption band of the solvatochromic dye and the absorbance of the band corresponding to a particular wavelength were used as measured magnitudes which are functionally related to the quantitative composition of the mixture. The 3rd order surface equation was fitted to the experimental data via the multidimensional regression method. Various pairs of macroscopic features were tested to obtain the best results. To find the solution, the set of three equations were calculated, in which two equations were the mathematical description of particular macroscopic features; the third one resulted from the definition of mass fraction. The detection and determination limits as well as the error of the method were determined which proved that the refractive index and the density were the most adequate pair of macroscopic features.