PHOTOMETRIC DETERMINATION OF CADMIUM(Ⅱ) BY THE FORMATION OF TERNARY COMPLEX WITH POTASSIUM IODIDE AND RHODAMINE B

In a sulfuric acid solution of 0.12 mol·L-1 and in the presence of PVA,a ternary complex was formed among Cd(Ⅱ),KI and rhodamine B,which was stable for at least 1 h.Beer′s law was held in the range of 0-3 μg/25 mL of Cd(Ⅱ),giving the molar absorptivity (ε) 6.84×105L·mol-1·cm-1 at its absorption maxima of 605 nm.It its application to the determination of cadmium in lake water.RSD′s of the analytical results were less than 0.6%,and recoveries found were in the range of 98.2%-100.1%.