Chemometrics-enhanced Kinetic Spectrophotometric Method for Simultaneous Determination of Ag+, Cu2+ and Ni2+ Ions in Some Medicinal Plants by Dimethyl 2,2’-(ethan-1,2-diylbis1) bis (cyclopent-1-ene-1-carbodithioate

The metal ions constituents of plants is reliable for determination of their medicinal, nutritional and toxicity properties. 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). All experimental conditions, including DEBC concentration, and the effects of pH and temperature were 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 detection values were 0.013, 0.078 and 0.003 mg l-1 and limit of quantification 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). 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. The proposed method was successfully applied to the simultaneous determination of metal ions in medicinal plant samples. The results of the proposed method were compared by those obtained on the same samples using Graphite furnace atomic absorption spectrometry.