Spectrophotometric study of a titanium(IV)-peroxide-1-(2-pyridylazo)-2-naphthol system in the presence of a non-ionic surfactant

Abstract

The titanium(IV)- hydrogen peroxide - 1-(2-pyridylazo)-2-naphthol [Ti(IV)-H₂O₂- PAN] system has been studied spectrophotometrically in the presence of Nemol K1030 (polyoxyethylene nonylphenol). The reagent-complex system is dissolved in the surfactant by the formation of micelles. The optimum conditions for the determination of titanium(IV) were studied and found to be as follows: pH 4 (acetic acid-acetate buffer); surfactant 1.5%m/V; λ_max., 529 nm; temperature 25 °C; and time 1 h. The stoicheiometric ratio of the Ti(IV)-H₂O₂- PAN complex was found to be 1 : 1 : 1 and the over-all formation constant (log β) 9.77. The system obeyed the Beer-Lambert law over the titanium(IV) concentration range 0.25–6.25 p.p.m. and the molar absorptivity at 529 nm was 1.1 × 10⁴ l mol^–1 cm^–1. The relative standard deviation for the titanium(IV) concentration was 1.40–0.04% in the range 0.50–3.50 p.p.m.; the limits of quantitation and detection were 0.17 and 0.05 p.p.m., respectively. The selectivity with respect to 17 species was also studied.