Study on Color Reaction of DBC-arsenazo with Chromium(III)

In a buffer medium of Clark-Lubs at pH 2.0,DBC-arsenazo reacts with chromium(Ⅲ) to form a violet-red complex with a composition of 1∶1.The maximum absorption wavelength of the complex is 600 nm.The apparent molar absorptivity of the method is e600 nm=1.87×104 L·mol-1·cm-1.Beer's law is followed over the concentration range of 0～3 mg/L of chromium(Ⅲ).The method is successfully used in determining chromium in cabbage samples.The analytical results accordes with those of contrast method atomic absorption spectrometry.The recovery of standard addition of the method for the determination of chromium was 98.0%～102%.The relative standard deviation of thirteen replicate determinations was 1.6%～2.5%.