Lead-selective membrane potentiometric sensor based on an 18-membered thiacrown derivative

A PVC-based membrane electrode for lead ions based on hexathia-18-crown-6-t etraone as membrane carrier was prepared. The influence of membrane composi tion, pH of test solution and foreign ions on the electrode performance wer e investigated. The electrode showed a Nernstian response over a lead conce ntration range from 1.0 x 10(-6) to 8.0 x 10(-3) M at 25 degreesC, and was found to be very selective, precise and usable within the pH range 3.0 - 6. 0. The electrode was successfully used as an indicator electrode in potenti ometric titration of lead ions and in direct determination of lead in water samples.