Cu(II)-All Solid State Ion Selective Electrode (ASS-ISE) with a Nano-molar Detection Limit and its Use for the Analysis of Waste Water Samples

An all-solid-state ion selective electrode (ASS-ISE) has been developed and used for the selective determination of Cu(II) in the presence of interfering species in complex samples. The device is composed of a conductive graphite-epoxy resin composite coated on a copper wire to act as the ASS, which is further coated with a Cu(II) selective PVC membrane, containing 30% PVC, 60% 0-nitrophenyloctyl ether (NPOE), 3% of sodium tetraphenyl borate, and 7% of 2-(1՛-(4՛-(1՛՛-Hydroxy-2՛՛-naphthyl)methyleneamino)butyl iminomethyl)-1-naphthol as the selective ion-carrier (L). The behavior of the device revealed that it has a Nernstian response of 29.7±0.2 mV/decade over a rather wide concentration range from 1.0×10-8 M to 1.0×10-3 M and the ASS-ISE could be used down to detection limits as low as 5.5×10-9 M. Further evaluations of the electrode proved it to have a good selectivity for Cu(II) as opposed to different commonly occurring interfering ions. The applicability of the ASS-ISE to the analysis Cu(II) concentration in copper electroplating waste water samples with complex matrices was also evaluated and found to be viable.