Novel erbium (III)-selective fluorimetric bulk optode

For the first time a highly sensitive and selective fluorimetric optode membrane was prepared for the determination of trace amounts of Er(III) ions. The Er(III) sensing system was constructed by incorporating 5-(dimethylamino) naphthalene-1-sulfonyl-4-phenylsemicarbazide (L) as a neutral Er(III)-selective fluoroionophore, in the plasticized PVC-membrane containing sodium tetraphenyl borate as a lipophilic anionic additive. The response of the optode is based on the strong fluorescence quenching of L by Er(3+) ions. At a pH value of 5.0, the proposed optode displays a wide concentration range of 1.0 x 10(-10) to 1.0 x 10(-2) M, with a relatively fast response time of less than 50 s. In addition, to high stability and reproducibility, the sensor shows a unique selectivity towards Er(3+) ion with respect to common cations. The proposed optode was applied successfully to the trace determination of erbium ion in binary mixture and water samples. (c) 2009 Elsevier B.V. All rights reserved.