New copper(II)-selective chemically modified carbon paste electrode based on etioporphyrin I dihydrobromide

A new chemically modified carbon paste electrode (CMCPE) based on etioporphyrin I has been developed for the determination of Cu2+ in real samples. The performance of this electrode was investigated using potentiometric measurements. The developed sensor exhibits a good linear response with a slope of 30.30 mV per decade over the concentration range of 1.28 × 10−6–1.28 × 10−2 mol L−1. It has a very low limit of detection, 8.99 × 10−7 mol L−1, with response time of 5 s. The proposed electrode revealed very good selectivities with respect to alkali, alkaline earth and some transition metal ions and could be used in pH range of 4.5–8.5. The thermal stability of the electrode was studied. This modified electrode was successfully applied as an indicator electrode for potentiometric titration of Cu2+ with EDTA and CDTA. Also the electrode was applied for direct determination of copper in different water samples, milk powder, brass powder and copper rod.

Based on the unique configuration of etioporphyrin and the extremely high stability of its metal-complexes, the compound is considered highly attractive material for developing potentiometric metal ion-sensor. Incorporating etioporphyrin in carbon paste plasticized with a solvent such as DOA resulted in a novel sensitive sensor to Cu(II) ions.Figure optionsDownload as PowerPoint slideHighlights
► Copper(II) chemically modified carbon paste electrode was constructed using etioporphyrin ligand.
► The electrode exhibits a good linear response of slope 30.3 mV/decade and LOD of 8.99 × 10−7 mol L−1.
► Anionic additive was found to improve the slope and the detection limit of the electrode.
► The electrode was found to have very fast response time of 5 s.
► Successful determination of copper in real samples using the proposed electrode was performed.