A simple sensitive precise and accurate method for the spectrophotometric micro determination of both Schiff’s base which is derived from Salicylaldehyde and Sulphanilamide (SASN) and also the catalyst Mn(II) is proposed using the redox reaction between H2O2 and the Schiff’s base in the presence of 10% (v/v) DMF solvent and alkaline buffer solution of pH 10 and at a concentration of 1 x 10-3 H2O2 catalyzed by Mn(II) at a wavelength of 445nm. The method proposed is suitable for the spectrophotometric determination of the Schiff’s base (SASN) in the concentration range 2 x 10-4 M to 10 x 10-4 M(55µg/ml to 276 µg/ml) and the estimation of Mn(II) in the range 11 ng/ml to 88 ng/ml. The results agree well with initial kinetic rate method. The thermodynamic parameters are evaluated and the effect of various foreign ions on the redox reaction is also presented. The molar absorptivity and the Sandell sensitivity in respect of SASN estimation are 2 X 103 lit. mole-1. cm-1 and 0.1380 µg/cm2 and that in the case of Mn(II) determination are 2 X 105 lit. mole-1. cm-1 and 0.0002747 µg/cm2 respectively.
