Selective Fluorimetric Recognition of Cesium Ion by 15-Crown-5-Anthracene

A selective fluorescent cesium optode on a chromoionophore consisting of anthracene covalently linked through an imine bond to a 15-crown-5 derivative has been reported. In the present system, 15-crown-5 derivative including anthracene was used a fluoroionophore. The fluorescence response mechanism is based on the photo-induced electron transfer (PET) from the lone pair of electrons of the nitrogen to the anthracene group and inhibition of PET system by cesium binding while increasing the fluorescence intensity. Emission intensity 15-crown-5 anthracene was measured at 500 nm with absorbance at 400 nm in CH₃CN–H₂O (1:1) media. The method shows a very good selectivity and sensitivity for cesium with respect to other cations such as K⁺, Na⁺ and Li⁺ with linear range and detection limit of 5.0 × 10⁻⁵ to 5.0 × 10⁻¹M and 3.0 × 10⁻⁶M respectively.