Micellar systems in flow injection: determination of gadolinium with 1-(2-pyridylazo)-2-naphthol in the presence of Triton X-100

Abstract

The optimum conditions for the determination of Gd using the Gd–1-(2-pyridylazo)-2-naphthol (PAN) system in micelles of Triton X-100 have been studied. Under the conditions chosen, the molar absorptivity was 4.8 × 10⁴ dm³ mol^–1 cm^–1. It is possible to determine Gd at levels of between 0.9 and 8.8 µg ml^–1 by injection into a stream, buffered at pH 9.2, containing 1.2 × 10^–3 mol dm^–3 PAN (Triton X-100: PAN = 0.15 g: 1.0 mg). The influence of the presence of electrolytes in the matrix on peak height was studied. The interferences produced by heavy metals were eliminated by extracting their diethyldithiocarbamates into CHCl₃—EtOAc (1 + 1).