Determination of Hg(II) ions in water samples by a novel Hg(II) sensor, based on calix 4 arene derivative
A PVC membrane electrode for Hg(II) ions, based on a new cone shaped calixarene (L) as a suitable ionophore was constructed. The sensor exhibits a linear dynamic in the range of 1.0 10-6-1.0 10-1 M, with a Nernstian slope of 29.4 0.4 mV decade-1, and a detection limit of 4.0 10-7 M. The response time is quick (less than 10 s), it can be used in the pH range of 1.5-4, and the electrode response and selectivity remained almost unchanged for about 2 months. The sensor revealed comparatively good selectivity with respect to most alkali, alkaline earth, and some transition and heavy metal ions. It was successfully employed as an indicator electrode in the potentiometric titration of Hg2+ ions with potassium iodide, and the direct determination of mercury content of amalgam alloy and water samples.