N,N-Dimethy1-4-arnino pyridine (DMAP) as a novel and sensitive reagent for the " spectrophotometric determination of copper(II)

The present work deals with the spectrophotometric determination of copper(II) with N,N-dimethyl-4-amino pyridine (DMAP) as a chromogen. This method developed by the authors is found to be simple, accurate and precise for the determination of copper(II) by spectrophotometry. It was noticed that, during the reaction in aqueous media, between copper(II) and DMAP, an instantaneous, stable, clear ink blue colored product was formed without any precipitate or turbidity. The resultant ink blue colored product showed a maximum absorbance at 670 am. Beer's law was found to be obeyed up to 30 mg of copper(II). Correlation factor was found to be 0.9862; SD and RSD were found to be well within the prescribed limits. Copper in other oxidation states other than +2, did not show such reaction with the chromogen DMAP. Hence it is concluded that the method developed by the authors is sensitive, advantageous and useful for the determination of copper(II) by spectrophotometry using DMAP as a reagent. The other foreign metal ions such as Fe-II, Ni-II, Sn-II, Sn-IV, Co-II, Pb-II, Zn-II, Ag-I did not interfere in the determination.