Method for determining cadmium in aqueous solutions containing calcium ions

摘要

In order to determine cadmium in aqueous solutions containing calcium ions, for example in waste waters, a sample of the aqueous solution containing a high calcium ion concentration is first admixed with a cyanide solution forming a cadmium complex and then with a molecular sieve, whereupon the molecular sieve with the calcium ions adhering therein is filtered off and the cadmium is subsequently unmasked. The sample thus processed is admixed with 1-(4-nitrophenyl)-3-(4-phenylazophenyl)-triazene (cadion), which reacts with the cadmium to form a cadmium-cadion complex. The brightening of the solution arising therefrom is measured photometrically and the cadmium content of the sample is determined on the basis of the brightening.