Spectrophotometric Determination of Cadmium in Water Samples with 1-(4-Antipyrine)-3-(3-nitroaniline)-triazene as Chromogenic Reagent

A new triazene reagent 1-(4-antipyrine)-3-(3-nitroaniline)-triazene(ANTA) was synthesized,and used as a new chromogenic reagent for cadmium(Ⅱ).In a Na2B4O7-NaOH buffer solution of pH 10.2,and in the presence of Tween-80,a stable coordination complex with the molar ratio of 2 to 1 was formed,with its absorption maximum at the wavelength of 508 nm.Value of apparent molar absorptivity was found to be 3.4×105L·mol-1·cm-1.Beer′s law was held in the range of 30.0-450 μg·L-1,with detection limit(3σ/k) of 10.0 μg ·L-1.The proposed method was applied to the determination of cadmium in waste water samples,giving results in consistency with those obtained by AAS.Average values of recovery found were 103.5% and 4% respectively.