Optical and Chromaticity Characteristics of Cobalt and Palladium 4-(2-Pyridylazo)resorcinates

Optical and chromaticity characteristics (diffuse reflectances, chromaticity coordinates, lightness, color saturation, yellowness, color tint, and whiteness) of cobalt and palladium complexes of 4-(2-pyridylazo)resorcinol were determined at pH 7.2–7.9 and in 1 M H₂SO₄. The conditions of the separate determination of cobalt and palladium in the presence of each other by changing the order of the addition of reagent and using bifunctional chromaticity measurements and two-wavelength spectrophotometry are specified. The advantages of the chromaticity measurements are demonstrated. The proposed procedures were used for the analysis of model mixtures, binary cobalt–palladium alloys, and cobalt and palladium catalysts.