Rapid determination of trace level copper in tea infusion samples by solid contact ion selective electrode.

A new solid contact copper selective electrode with a poly (vinyl chloride) (PVC) membrane consisting of o-xylylenebis(N,N-diisobutyldithiocarbamate) as ionophore has been prepared. The main novelties of constructed ion selective electrode concept are the enhanced robustness, cheapness, and fastness due to the use of solid contacts. The electrode exhibits a rapid (< 10 seconds) and near-Nernstian response to Cu activity from 10 to 10 mol/L at the pH range of 4.0-6.0. No serious interference from common ions was found. The electrode characterizes by high potential stability, reproducibility, and full repeatability. The electrode was used as an indicator electrode in potentiometric titration of Cu(II) ions with EDTA and for the direct assay of tea infusion samples by means of the calibration graph technique. The results compared favorably with those obtained by the atomic absorption spectroscopy (AAS).