A Novel Fluorescent Cesium Ion-Selective Optode Membrane based on 15-Crown-5-Anthracene

An optode system based on a plasticized polymer membrane containing cesium ion-selective fluoroionophore and lipophilic anions for the determination of cesium ions has been developed. In this work, 15-crown-5 derivative including anthracene was used as a fluoroionophore. Emission intensity of the optode membrane incorporating 15-crown-5-anthracene was measured at 500 nm with excitation at 360 nm in the presence of Tris-HCl buffer solution. Under optimum experimental condition, the relative fluorescence intensity was linear with the concentration of cesium ion in the range of 1.0 × 10^-4 M to 1.0 × 10^-1 M and the detection limit was obtained 4.2 × 10^-5 M, as defined by LOD = 3 × S_b/m (where S_b=standard deviation of blank signal and, m=slope of the calibration curve). The effect of pH of sample solution on the fluorescent response, the selectivity, response time and reproducibility of the optode membrane were also discussed. The fluorescent optode system shows a high selectivity and sensitivity for cesium ion with respect to other cations such as K⁺, Na⁺ and Li⁺.