Nano-molar Monitoring of Copper ions in Waste Water Samples by a Novel All-Solid-State Ion Selective Electrode (ASS-ISE)

The focus of this work is on the preparation of a Cu2+ all-solid-state ion selective electrode (ASS-ISE) to be used in the analysis of copper ions in complex samples. The ASS-ISE was composed of a conductive substrate of graphite-epoxy resin on a copper wire. This conductive substrate was further coated with a layer of Cu2+-selective PVC membrane, comprising 32% of PVC, 57% of nitrobenzene (NB) as the plasticizing solvent, 2% of an ionic additive (i.e. sodium tetraphenyl borate (NaTPB)), and 9% of an organic ligand named 3-(2-methyl-2,3-dihydrobenzothiazol-2-yl)-2H-chromen-2-one (L) as the selective ionophore. The device with the optimal composition had a Nernstian response of 29.3±0.3 mV/decade from 1.0×10-8 M to 1.0×10-3 M of the analyte and its lower detection limit was estimated at be 4.0×10-9 M. The ASS-ISE showed excellent selectivity for the target ion in the presence of various common interfering ions, and was found to be satisfactorily applicable to the analysis of copper electroplating waste water samples.