محمد رضا محمدی زاده

A novel, simple and accurate spectrophotometric method was developed for the simultaneous determination of Ag , Cu2 and Ni2 ions in different medicinal plants without prior separation steps. This method was based on the different kinetic characteristics between the reactions of analytes with newly synthesized Schiff base as dimethyl 2,2’,-(ethan-1,2-diylbis1)bis(cyclopent-1-ene-1-carbodithioate(DEBC) as the color-forming reagent. All experimental conditions include, DEBC concentration, effects of pH and temperature was optimized. Also, orthogonal array design was applied for the construction of concentration. The differential kinetic spectra were monitored and recorded at 397 nm. The reaction orders were estimated with respect to complex mixture of analytes with DEBC. Limit of detections (LOD) values were 0.013, 0.078 and 0.003 mg L-1 and limit of quantifications (LOQ) values were 0.043, 0.250 and 0.011 for, Cu2 , Ni2 and Ag , respectively. The recorded data were processed by principal component analysis- back propagation neural networks (PCBPNNs The obtained optimum models were used to predict concentration of analytes. A set of synthetic mixtures of metal ions was evaluated and the obtained results by PCBPNNs were discussed. The simultaneous analysis was also performed without compressed data and was compared with those obtained by PCBPNNs. Finally the proposed method was successfully applied to the simultaneous determination of metal ions in different medicinal plants samples. The results of proposed method were compared by those obtained on the same samples by Graphite furnace atomic absorption spectrometry (GFAAS).