3,4-Dihydroxybenzoic Acid As A Reagent for the Spectrophotometric Determination of Titanium

Abstract

The reaction between titanium(IV) and 3,4-dihydroxybenzoic acid in aqueous media results in an intensely colored complex which is stable for at least 8h. It allows the spectrophotometric determination of titanium in silicate rocks. The proposed method, in pH 4.0–6.0, shows a molar absorptivity of 1.43.10⁴ L.mole^?1.cm^?1 at 380 nm. Beer's Law is obeyed up to 3.0 μg/mL of titanium(IV). The interference of iron(III) can be eliminated by reduction to iron(II) with hydroxylamine hydrochloride. The method was applied to the determination of titanium in various standard rocks and the results indicated that the accuracy and precision are satisfatory.