Complexation equilibria between gallium(III) and 4-(4'-methyl-2'-thiazolylazo)-2-methylresorcinol. Derivative spectrophotometric determination of gallium in biological samples

Abstract

The reaction of Ga(III) with 4-(4'-methyl-2'-thiazolylazo)-2-methylresorcinol (H2L) at I = 0.25 mol l-1, (NaNO3) was investigated spectrophotometrically. Numerical method was used to evaluate the stability constants of the complexes formed GaH2L2 (log β122 = 37.03±0.09); GaHL (log β111 = 19.08±0.06); GaL (log β101 = 13.65±0.16). A method is developed for the determination of gallium using first and second derivative spectrophotometry and the effect of interferences has been evaluated. The method has been applied to the determination of gallium in human urine and blood serum samples.