Color Reaction of 2-Hydroxy-5-nitrophenyldiazoaminoazobenzene with Nickel and Its Analytical Application

A new reagent, 2 hydroxy 5 nitrophenyldiazoaminoazobenzene (HNPDAAB) has been synthesized, and the color reaction of nickel(Ⅱ) with this reagent was studied. In the presence of Triton X 100, Nickel(Ⅱ) reacts with HNPDAAB and forms a 1∶1 red complex. The molar absorptivity is 1.58×10 5 L·mol -1 ·cm -1 . Beer's law is obeyed in the concentration range of 0～9 μg/25 mL for nickel. The analysis results of trace nickel in alloy samples using this method are in agreement with those determined by AAS.