The reagent anthrone phenylhydrazone (APH) is used for the simultaneous determination of Co(II), Ni(II) & Cu(II) by fourth order derivative spectrophotometric method. The reagent APH gives light yellow colour with Co(II), Ni(II) & Cu(II) solution in basic medium. The maximum peaks were observed between 426.3-625 nm for Co(II), Ni(II) & Cu(II) in basic buffer solution of pH 10. The molar absorptivity and Sandell`s sensitivity of Co(II), Ni(II) & Cu(II)-APH complexes are computed, the molar absorptivity are 1.5x104 L/mol/cm, 2.0x104 L/mol/cm and 2.163x104L/mol/cm respectively. The Sandell`s sensitivity are 0.0066 µg/cm2, 0.005 µg/cm2 and 0.0026 µg/cm2 respectively. The stability constant of Co(II), Ni(II) & Cu(II)-APH complexes are 1.530x105, 2.486x104 and 2.96x104 respectively. The effect of various concentrations of Co(II), Ni(II) & Cu(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.
APH, Simultaneous spectrophotometry, Cobalt(II), Nickel(II), Copper(II)