Extraction-spectrophotometric determination of zinc(ii) with 4-(2-pyridylazo)-resorcinol and a quaternary ammonium salt

Abstract

A simple and sélective extraction spectrophotometric determination of zinc is described. The complex [Zn(PAR) 2](CDBA) 2, where PAR is the 4-(2-pyridylazo)resorcinol anion and CDBA is cetyldimethylbenzylammonium ion, is extracted from a solution buffered at pH 9.7 with carbonate/bicarbonate. Beer's law is obeyed over the range 0.2–1.2 ppm zinc, the molar absorptivity being 9.2 × 10 4 1 .mole −1.cm −1. The precision in this range is 0.0056 ppm. Cadmium in up to a 50-fold w w ratio may be masked with diethyldithiocarbamate.