The Synthesis and Color Reaction of 2,2-bi-3,3′-disulphodiazoaminoazobenzenylpropane with Nickel(II) and Its Application

A sensitive and selective chromogenic reagent of 2,2 bi 3,3′ disulphodiazoaminoazo benzenylpropane was synthesized and its color reaction with Nickel(Ⅱ) was studied. In the presence of surfactant Tween 80, the reagent reacts with Nickel(Ⅱ) to form a stable red complex with a molar ratio of 1∶2. In Na 2B 4O 7 NaOH buffer solution of pH 10.97, the maximum absorbtion of the complex is at 540 nm and the apparent molar absorbtion coefficient is found to be 2.06×10 5 L·mol -1 ·cm -1 . Beer's law is obeyed in the range of 0～15 μg of Nickel(Ⅱ) in 25 mL of solution. This method has been used to determine trace amounts of Nickel(Ⅱ) in hair, corns and vegetables after extraction with satisfactory results.