Potentiometric Iodide Selectivity of Polymer‐Membrane Sensors Based on Co(II) Triazole Derivative

The 3-amion-5-mercapto-1,2,4-triazole cobalt(II) [Co(II)AMETR] was used as a new carrier for preparing polymeric membrane selective sensor which exhibited high affinity for iodide ion. The effects of membrane composition, pH, the influence of lipophilic ion additives and plasticizer on the response characteristics of the sensor were investigated. The sensor showed a near Nernstian slope of - 56.6 mV/decade for I- ion over a wide concentration range from 8.5 x 10(-7) to 1.0 x 10(-1) M with a low detection limit of 5.1 x 10(-7) M. The sensor has a fast response time and could be used over a wide pH range of 2 - 8. The response mechanism is discussed in view of the AC impedance technique. The sensor was successfully applied to direct determination of iodide content in environmental water samples and mouth wash samples.