Uranyl Selective Polymeric Membrane Sensor Based on P-Tert-Butyl-Biscalix[4]Arene

In recent years, the monitoring and evaluation of uranyl (uo22+) has receivedgrowing attention from both nutritional and toxological points of view. in this experimentalstudy, we revealed that an electroactive material p-tert-butyl-biscalix[4]arene can be used asan ionophore in the preparation of pvc based ion selective electrode and we found that itshows ionophoric binding property for uranyl cation. this electrode shows excellentselectivity for uo22+ with respect to most of the common cations including inner transitionand heavy metal ions. the proposed membrane sensor with p-tert-butyl-biscalix[4]arenebased receptor exhibits wide linear range, with the slope of 29.30±1.0 mv per decade overthe concentration range of 8.1×10-8 m-1.0×10-1 m, and membrane sensor shows a lowestdetection limit of 8.0×10-8 m of uo22+. this sensor satisfactorily works in aqueous media andin non-aqueous media it works upto 40% (water-ethanol, water-methanol, water-acetone andwater-acetonitrile). this electrode shows independent response within the ph range of 1.0-5.5and its fastest response time is 10 s. the proposed membrane electrode was appliedsuccessfully for the determination of uo22+ in the presence of other cations (binary mixtures)by direct potentiometry and in tap and sea-water samples.