Synthesis of 1-azobenzene-3-(5-bromo-2-pyridyl)-triazene and its color reaction with nickel

A new reagent 1-azobenzene-3-(5-bromo-2-pyridyl)-triazene(ABBPTA)as chromogenic reagent was synthesized and its color reaction with nickel has been investigated.In the presence of nonionic surfactant Triton X-100 and in the medium of pH 10.5 Na_2B_4O_7-NaOH,ABBPTA forms a red complex with Ni?.The apparent molar absorptivity of the complex is 2.11×10~5 L·mol~(-1)·cm~(-1) at maximum absorption of 540 nm.The molar ratio of Ni? to ABBPTA is 1∶4.Beer′s law is well obeyed in the range of 0-12 μg/25 mL for nickel.Most of common coexisting ions of the system don't interfere with the determination of nickel in samples.The method has been applied to the direct determination of nickel in aluminum alloys with recovery of 98.2%102.8% and RSD of 2.1%-2.4%.