Potentiometric Monitoring of Iodide Ions Using a Highly Selective Iodide Sensor Based on AgI-Cu2S-Multi Walled Carbon Nano Tube Material

Abstract

In this work, a new iodide selective sensor based on an AgI-Cu2S-Multiwalled carbonnanotube-Graphite-Paraffin oil composite material was described for highly selective potentiometric determination of iodide ions. To obtain the best potentiometric performance characteristics of the sensor, the sensor components was optimized and the sensor was formed by properly pressing of the optimized sensor components. The experimental results were showed that the most appropriate potentiometric response was achieved with the sensor materials containing a compositions of G:MWCNT:AgI:Cu2S:PO in the ratio 50:5:20:5:20 (% w/w). The developed sensor display a wide linear working range (1.0×10-5-1.0×10-1 molL-1) for iodide ions. In this linear working range, the Nernstian slope of the sensor was 51.5±1.0 mV and the correlation coefficient (R2) was determined as 0.9991. The sensor was of a very low response time (5s). The repeatability of the sensor potential response was very good and its response remained unchanged in the pH range of 6.0-9.0. The interference effect on the sensor response of different anionic species was tested by the separate solution method (SSM) and the sensor selectivity was quite good. The life time of the sensor was measured as 13 weeks and the sensor was successfully used as indicator sensor for the potentiometric titrations of iodide ions with silver nitrate solution. Additionally, the sensor was successfully applied for the direct detection of iodide ions in environmental water samples.