Simultaneous Fourth Order Derivative Spectrophotometric Determination of Cobalt, Nickel and Iron Using Anthrone Phenylhydrazone (APH)

The reagent anthrone phenylhydrazone (APH) is used for the simultaneous determination of Co(II), Ni(II) and Fe(II) by fourth order derivative spectrophotometric method. The reagent APH gives light yellow colour with Co(II), Ni(II) and Fe(II) solution in basic medium. The maximum peaks were observed between 426.3 nm-625 nm for Co(II), Ni(II) and Fe(II) in basic buffer solution of pH 10. The molar absorptivity and Sandell`s sensitivity of Co(II), Ni(II) and Fe(II)-APH complexes are computed, the molar absorptivity are 1.5x10<sup>4</sup> L/mol/cm, 2.0x10<sup>4</sup> L/mol/cm and 1.3x10<sup>4</sup>L/mol/cm respectively. The Sandell`s sensitivity are 0.0066 μg/cm², 0.005μg/cm² and 0.0076 μg/cm² respectively. The stability constant of Co(II), Ni(II) and Fe(II)-APH complexes are 1.530x10⁵, 2.486x10⁴ and 1.049x10⁴ respectively. The effect of various concentrations of Co(II), Ni(II) and Fe(II) ions on amplitude also studied. The samples of grape leaves, sesame, laver, mung bean and alloy samples were analyzed by the proposed method. The results of the food samples and alloy samples are good agreement with the results of APARI, AAS methods.