Comparison of spectrophotometric methods of determination of zinc(II) in biological material and study of its complex formation reactions with 4-(2-pyridylazo)resorcinol

Abstract

The methods of determination of Zn(II) with dithizone, zincone, PAN, and PAR were compared by considering the fundamental parameters of the photometric methods. The compositions, values of the molar absorptivities, and values of the equilibrium and stability constants of the complex species MLH, ML, ML2H2, ML2H, and ML2 of zinc(II) with PAR were determined graphically by means of the slope-intercept transformations, and numerically from the absorbance-pH curves and from the absorbance dependences on the component concentrations by employing the program PRCEK T200 and from the continual variations curves by using the program JOBCON.