New lead-sensitive ion selective electrode with low detection limit

C Wardak,J Lenik

doi:10.1051/e3sconf/20130105010

Abstract

A new polyvinylchloride membrane sensor for Pb 2+ with solid contact has been prepared. The electrode membrane phase contains 1-heksyl-3-methylimidazolium hexafluorophosphate (HMImPF6) as lipophilic ionic additive. The electrode shows a Nernstian response for lead ions over a wide concentration range (1x10 -8 -1x10 -1 mol L -1 ) and the slope of 28.1 mV/decade. The limit of detection is 2.3x10 -9 mol L -1 . It has a fast response time of 5-7 s and can be used more than 2 months without any divergence in potential. The proposed sensor is not pH sensitive in the range 4.0-6.9 and shows a very good discriminating ability towards Pb 2+ 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 Pb 2+ ions in real sample solution.

Highlights

IntroductionLead causes atmospheric and water pollution due to its application in various industrial products
Determination of lead is very important because it is highly toxic element
It was found that ionic liquid can replace the commonly used lipophilic ionic additives in the membrane phase [Wardak 2009, 2012]

Summary

Introduction

Lead causes atmospheric and water pollution due to its application in various industrial products. In the environment it is generally present as inorganic Pb2+ which can be detected and determined by lead ion-selective electrode (ISE). The mechanism of the potential formation of ion selective electrodes with a liquid or pseudoliquid (polymeric) membrane depends strongly on extraction and ion-exchange processes between the aqueous and organic phases [Sandblom 1967, Morf 1999]. It was found that ionic liquid can replace the commonly used lipophilic ionic additives (phenyl botates) in the membrane phase [Wardak 2009, 2012]

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