Novel fluorimetric bulk optode membrane based on a dansylamidopropyl pendant arm derivative of 1-aza-4,10-dithia-7-oxacyclododecane ([12]aneNS2O) for selective subnanomolar detection of Hg(II) ions

A novel fluorescence chemical sensor for the highly sensitive and selective determination of mercury(II) ions in aqueous solutions is prepared. The mercury sensing system was prepared by incorporating 1-(dansylamidopropyl)-1-aza-4,10-dithia-7-oxacyclododecane (L) as a neutral Hg2+-selective fluoroionophore in the plasticized PVC membrane containing potassium tetrakis(p-chlorophenyl)-borate as a liphophilic anionic additive. The response of the sensor is based on the strong fluorescence quenching of L by Hg2+ ions. At a pH 3.3, the proposed sensor displays a calibration curve over a wide concentration range of 1.0 x 10(-4) to 5.0 x 10(-12) M, with a relatively fast response time of less than 1 min. In addition to high stability and reproducibility, the sensor shows a unique selectivity towards Hg2+ ion with respect to common coexisting cations. The proposed fluorescence optode was applied to the determination of mercury content of amalgam alloy, hair and well water samples. (c) 2004 Elsevier B.V. All rights reserved.