Spectrophotometric determination of zinc with thiocyanate and rhodamine 6G

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.