Spectrophotometric Determination of Antimony(III) as Pyrocatechol Violet Complex with Tetraphenylphosphonium Chloride

Abstract

The spectra of antimony(III)-Pyrocatechol Violet(PV) complexes were given rise to bathochromic shifts about 100 nm by the addition of tetraphenylphosphonium cation in aqueous solution. An absorbance at 630nm was little affected by that of reagent blanks and gave a good sensitivity for the spectrophotometric determination of antimony(III). The molar absorptivity was 16500dm³ mol^-1 cm^-1 in the presence of 0.024mol dm^-3 TPPC and 2.0×10^-4mol dm^-3 PV concentrations at the pH ranges from 2.5 to 4.5, and this solution was stable up to 20h in the presence of 0.1% gum arabic.