Application of multicomponent spectrophotometry to analytical control of electroplating solutions

Summary A procedure for the simultaneous spectrophotometric determination of organic additives and the quantitation of Ni(II) in Zn-Ni electrolytic baths is described. Organic additives were determined by resolving the mixed spectrum over the wavelength range 278–330 nm by applying a least-squares fitting computational program to the standard spectrum of each component. Spectra were recorded on a hydroalcoholic medium (15% methanol) containing 0.1 mol/l NH₄Cl. The Ni(II) concentration was determined by applying the program to the first-derivative spectrum over the wavelength range 660–820 nm.