Fluorometric determination of mercury (II) with pyronine G

Abstract

Pyronine G reacts with mercury in hydrobromic acid medium to form a Pyronine G-mercury complex with reddish orange fluorescenece, and was used as a reagent for the fluorometric determination of mercury. The kind of acids and solvents, concentration of acid and reagent and the effect of diverse ions were investigated. For the determination of mercury, 1.0 ml of 0.3% Pyronine G solution was added to the sample solution containing (0.11.0)μg of mercury, and the acid concentration was adjusted to (0.010.03)N in hydrobromic acid (final volume: 5 ml). The Pyronine G-mercury complex was extracted with 5 ml of butyl acetate, benzene ₊ acetone or toluene ₊ acetone. The organic phase was separated and centrifuged, and its fluorescence (ex. 365 nm, fl. 580 nm) was measured against the reference Rhodamine B solution (0.2 μg/ml). Au(III) and Cr(VI) interfered. The method is simple and accurate for the determination of mercury. The limit of determination was 0.05μg Hg/ml in benzene-acetone mixed solvent.