Synthesis of 4-(4-antipyrinylazo) Resorcinol and Its Colour Reaction With In(III)

4-(4-Antipyrinylazo) resorcinol was synthesized,and its structure was identified by IR spectroscopy.The Colour Reaction of the reagent with indium(Ⅲ) was investigated.It was found that the color reagent reacted with indium(Ⅲ) to form a stable orange complex in HAc-NaAc buffer solution at pH 5.0.The maximum absorption wavelength was at 480 nm and apparent molar absorptivity was of 3.1×104 L·mol-1·cm-1.Beer's law was obeyed for indium(Ⅲ) mass concentrate in the range of 0 to 40 μg/25 mL.