Spectrophotometric determination of cadmium by the chromogenic reagent 2-pyridinediazoaminoazobenzene in the presence of Triton X-100

Abstract

A highly sensitive spectrophotometric method for determination of cadmium by the chromogenic reagent 2-pyridinediazoaminoazobenzene (Cadion Py) has been developed. In the presence of Triton X-100 and NH₃—NH₄Cl buffer solution, the optimum conditions for colour reaction of cadmium with Cadion Py, the molar absorptivity of which is 1.92 × 10⁵ l mol^–1 cm^–1 at 530 nm, are studied. Elimination of interfering ions at ten-fold concentration is achieved by adding a mixed masking agent. Trace amounts of cadmium in water or waste water samples has been satisfactorily determined by the method.