Potentiometric Cu2+-selective electrode with subnanomolar detection limit Original Research Article

A PVC membrane Cu2+ ion-selective electrode has been constructed using a new compound ethyl 1,2,3,4-tetrahydro-4-(4-methoxyphenyl)-6-methyl-2-oxopyrimidine-5-carboxylate (ETMOC) as a neutral ionophore. The electrode works properly. It responds to Cu2+ ion with a sensitivity of 29.5 ± 0.2 mV/decade over the range of 1.0 × 10− 9 to 5.0 × 10− 1 M at pH 3.0–8.0. The limit of detection was 4.5 × 10− 10 M. It has a response time of < 6 s and can be used for at least 3 months without any divergence in potentials. The proposed electrode shows fairly good discrimination of Cu2+ ion from several cations. The effect of organic solvents on electrode response shows that this electrode can be used in methanol and ethanol media until 15% (v/v) concentration without interference. This sensor was used to determination of Cu2+ concentration in Tea leaves, Milk powder and Drinking water samples.