Lead(II) potentiometric sensor based on 1,4,8,11-tetrathiacyclotetradecane neutral carrier and lipophilic additives

potentiometric sensor for lead(II) ions based on the use of 1,4,8,11-tetrathiacyclotetradecane (TTCTD) as a neutral ionophore and potassium tetrakis-(p-chlorophenyl)borate as a lipophilic additive in plasticized PVC membranes is developed. The sensor exhibits linear potentiometric response towards lead(II) ions over the concentration range of 1.0 x 10(-5)- 1.0 x 10(-2) mol L-1 with a Nernstian slope of 29.9 mV decade(-1) and a lower limit of detection of 2.2 x 10(-6) mol L-1 Pb(II) ions over the pH range of 3-6.5. Sensor membrane without a lipophilic additive displays poor response. The sensor shows high selectivity for Pb(II) over a wide variety of alkali, alkaline earth and transition metal ions. The sensor shows long life span, high reproducibility, fast response and long term stability. Validation of the method by measuring the lower limit of detection, lower limit of linear range, accuracy, precision and sensitivity reveals good performance characteristics of the proposed sensor. The developed sensor is successfully applied to direct determination of lead(II) in real samples. The sensor is also used as an indicator electrode for the potentiometric titration of Pb(II) with EDTA and potassium chromate. The results obtained agree fairly well with data obtained by AAS.