Development of a new copper(II) ion-selective poly(vinyl chloride) membrane electrode based on 2-mercaptobenzoxazole

Copper(II) ion-selective PVC membrane electrode based on 2-mercaptobenzoxazole as a new ionophore and o-nitrophenyl octyl ether (o-NPOE) as plasticizer is proposed. This electrode revealed good selectivity for Cu2+ over a wide variety of other metal ions. Effects of experimental parameters such as membrane composition, nature and amount of plasticizer, and concentration of internal solution on the potential response of Cu2+ sensor were investigated. The electrode exhibits good response for Cu2+ in a wide linear range of 5.0 x 10(-6)-1.6 x 10(-2) mol/L with a slope of 29.2 +/- 2.0 mV/decade. The response time of the sensor is less than 10 s, and the detection limit is 2.0 x 10(-6) mol/L. The electrode response was stable in pH range of 4-6. The lifetime of the electrode was about 2 months. The electrode revealed comparatively good selectivities with respect to many alkali, alkaline earth, and transition metal ions.