Spectrophotometric determination of zinc with thiocyanate and Rhodamine 6G

Abstract

A sensitive and selective method is described for the spectrophotometric determination of zinc. The method is based on the reaction of Rhodamine 6G with the tetrathiocyanatozincate(II) anion to form a pink product that is stabilised by gelatin. The colour development is rapid and remains stable for at least 3 h. Zinc contents as low as 0.2–5.0 µg in 10 ml of sample can be readily determined. The method is precise and has been applied to the determination of zinc in synthetic matrices and soil samples.