A highly selective and sensitive disposable carbon composite PVC-based membrane for determination of lead ion in environmental samples.

A Pt wire coated with phenyl hydrazone derivative-carbon composite in a poly(vinyl chloride) membrane was used for detection of lead. The sensor had a Nernstian slope of 29.46+/-0.41 mV/decade over a wide linear concentration range of 7.7 x 10(-7) to 1.0 x 10(-1) mol L(-1) for Pb(NO(3))(2). The detection limit was 3.2 x 10(-7) mol L(-1) and the electrode was applicable in the pH range of 3.7-6.3. It had a short response time of approximately 6s and was used at least for 70 days. The electrode has exhibited good selectivity for Pb(II) relative to 19 other metal ions. The functionality of the proposed sensor was also investigated in binary water-alcohol mixture and it concluded that 23% water-methanol and 20% water-ethanol content could not bring out any changes in its potential. The practical analytical utility of the electrode was demonstrated by measurement of Pb(II) in mineral rock and potentiometric titration of sulfate anion.