Extractive spectrophotometric determination of copper(II) and its applications in pharmaceutical samples and alloys

A new reagent isonitrosopropiophenone thiosemicarbazone (HINPTC) is proposed for extraction and spectrophptometric determination of copper. The reagent HINPTC reacts with copper to give yellow coloured complex, which can be quantitatively extracted into isoamyl alcohol at pH 10. The organic extract shows maximum absorption at 390 nm where absorption due to a similarly prepared reagent blank is negligible. The Beer's law is followed in the concentration range 0.5-6.0 μg/mL of copper. The molar absorptivity and Sandell's sensitivity of Cu(II)-HINPTC complex are 5.826 x 10 3 /mol/cm and 0.010 μg/mL/cm 2 ,respectively. The stoichiometry of extracted species is found to be 1:2 (M: L). The proposed method is rapid, sensitive, reproducible and is applied for the determination of copper in synthetic mixtures and real samples like pharmaceuticals, aluminium alloys (Al chips and Al pins), and brass ash. It also provides a relative inexpensive alternative to more expensive instrumental method like AAS.