Extractive spectrophotometric determination of mercury(II) with 4-(2-pyridylazo)resorcinol and a long-chain quaternary ammonium salt

Abstract

Mercury(II) can be extracted quantitatively as a 1:1:2 mercury-4-(2-pyridylazo)resorcinol-cetyldimethylbenzylammonium chloride ternary complex in the pH range 7–8. This ternary system obeys Beer's law in the range 0.5–6.25 µg ml^–1 of mercury. 1,10-Phenanthroline completely masks the extraction of Hg(II) in the presence of 4-(2-pyridylazo)resorcinol and cetyldimethylbenzylammonium chloride, whereas other divalent metal ions are quantitatively extractable, which can be exploited as an efficient technique for the separation of mercury from other divalent metal ions. Based on these results, useful procedures for the determination of mercury in medicinal samples and synthetic mixture were developed.