Synthesis and Color Reaction of 7-(2'-carboxylazo)-8-hydroxyquinadine, A New Reagent with Ni (II)

carboxylazo)-8-hydroxyquinadine (CAHQD), a new reagent was synthesized, and its' color reaction with Ni (II) was studied. In the presence of pH 5 buffer solution and OP, 7-(2-carboxylazo)-8-hydroxyquinadine reacted with Ni (II) to form a purple complex with the molar ratio of 2:1, whose absorption was 1.4×10~4 L·mol~(-1)·cm~(-1) at 570 nm. Beer's law was obeyed in the range of 0~30 μg/25mL in the measured solution with good sensitivity.