Study on the Synthesis of New Chromogenic Color Reagent and on Its Color Reaction with Cadmium

New chromogenic reagents,4-fluoro-4′-azobenzene-diazoaminobenzen,and its color reaction with cadmium was studied.In a pH 9.5 borate buffer medium and in the presence of Triton X-100,the reagent reacts with Cd( Ⅱ) to form a 1∶4 red complex.The absorption maxima of Cd-FADAB is at 524nm,with molar absorptivity of 1.79×105L·mol-1·cm-1.Beer's law is obeyed in the range of 0—10μg/25mL.The method was applied to the determination of cadmium in soil sample of environment.