Synthesis of 2-Sulfobenzene-1,4-diamino Diazoazobenzene and Its Colour Reaction with Nickel

A new chromogenic reagent 2-sulfobenzene-1,4-diamino diazoazobenzene was synthesized and its colour reaction with nickel(II) was studied.The reagent was reacted with nickel(II) to form a red complex in the medium of borax-sodium hydroxide buffer solution(pH10.5) with the existence of nonionic surfactant Triton X-100.The molar ratio of the complex was 3:1,with the maximum absorption at 545 nm and the miximum negative absorption at 433 nm.Beer's law was obeyed in the range of 0.12~ 0.28 mg of nickel in 25 ml solution,with the apparent molar absorptivity of 9.60×105 L× mol/cm.