A highly selective lead-sensitive electrode with solid contact based on ionic liquid

A new polyvinylchloride membrane sensor for Pb2+ with solid contact based on ionic liquid has been prepared. The electrode shows a Nernstian response for lead ions over a wide concentration range (1 × 10−8 to 1 × 10−1 mol L−1) and the slope of 29.8 mV/decade. The limit of detection is 4.3 × 10−9 mol L−1. It has a fast response time of 5-7 s and can be used for 4 months without any divergence in potential. The proposed sensor is not pH sensitive in the range 3.5-7.3 and shows a very good discriminating ability towards Pb2+ ion in comparison with some alkali, alkaline earth, transition and heavy metal ions. It was successfully applied as an indicator electrode in potentiometric titration of lead ions with K2CrO4 and for direct determination of Pb2+ ions in real sample solution.