Spectrophotometric Determination of Trace Cadmium in Tobacco with Tris-[2,4,6-(2-hydroxy-4-sulpho-1-naphthylazo)]-s-triazine, Trisodium Salt

Abstract

A simple, sensitive and selective spectrophotometric method is developed for the determination of cadmium in aqueous solution. The metal ion forms a dark brown coloured complex with tris-[2,4,6-(2-hydroxy-4-sulpho-1-naphthylazo)]-s-triazine, trisodium salt in the pH range 5.5-7.0. The complex shows maximum absorbance at 510 nm. Beer's law is obeyed in the range 0.0-2.4 ppm of Cd(II). The molar absorptivity and Sandell's sensitivity are 5 × 10⁴ L mol^-1 cm^-1 and 0.0021 μg cm^-2 respectively. The composition of the complex is 1:2. The effect of interfering ions has been studied and the method has been applied to determine Cd(II) in tobacco.