DETERMINATION OF Ni(II) IN METAL ALLOYS BY SPECTROPHOTOMETRY UV-VIS USING DOPASEMIQUINONE

A spectrophotometric method was proposed for Ni(II) determination in alloys using a dopa-semiquinone (L(-1)) to form [Ni(II)(L(1-))(3)](1-), epsilon = 9.3 x 10(3) L mol(-1) cm(-1). The optimal conditions for the determination were: wavelength 590 nm, temperature 25 degrees C, reaction time 45 min and pH 7.5. The Beer's law was obeyed for nickel from 3.33 x 10(-5) to 1.78 x 10(-4) mol L(-1). The method was applied to complex samples, such as inox, nickel-titanium and cobalt-chromium alloys. A study of the potential interferents revealed that Mn was the major interferent. The limit of detection and quantification were 2.88 x 10(-5) mol L(-1) and 3.06 x 10(-5) mol L(-1), respectively.