Novel fluorimetric bulk optode membrane based on 5,8-bis((5'-chloro-8'-hydroxy-7'-quinolinyl)methyl)-2,11-dithia-5,8-diaza-2,6-pyridinophane for selective detection of lead(II) ions.
ABSTRACT A novel fluorescence chemical sensor for the highly sensitive and selective determination of Pb(2+) ions in aqueous solutions is described. The preliminary potentiometric and spectrofluorimetric complexation studies in solution revealed that the lipophilic ligand 5,8-bis((5'-chloro-8'-hydroxy-7'-quinolinyl)methyl)-2,11-dithia-5,8-diaza-2,6-pyridinophane (L2) forms a highly stable and selective [PbL2](2+) and [Pb(L2)(2)](2+) complexes which results in a strong fluorescence quenching of the ligand. Thus, a novel fluorescence Pb(2+) sensing system was prepared by incorporating L2 as a neutral lead-selective fluoroionophore in the plasticized PVC membrane containing tetrakis(p-chlorophenyl) borate as a liphophilic anionic additive. The response of the sensor is based on the strong selective fluorescence quenching of L2 by Pb(2+) ions. At pH 5.5, the proposed sensor displays a calibration curve over a wide concentration range of 3.0 x 10(-7) to 2.5x 10(-2)M with a relatively fast response time of less than 5 min. In addition to high stability, reversibility and reproducibility, the sensor shows a unique selectivity towards Pb(2+) ion with respect to common coexisting cations. The proposed fluorescence optode was successfully applied to the determination of lead in plastic toys and tap water samples.
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ABSTRACT: In the past Pb(2+) has been used in many industries, including gasoline, piping, toys, paints, and more. The use of lead has led to a natural increase of lead concentration in the environment especially in air and water. According to the U.S. CDC "no level of lead in blood is considered safe." Exposure to very low amounts of lead can cause several health complications including developmental and neurological disorders. Over the past several years an emphasis has been placed in developing systems that can detect lead at a very low concentration. A great deal of work has been accomplished in the development of Pb(2+) sensors that can not only detect but also quantify the amount and in some cases in the presence of other metal ions. Herein, we describe current regulations, mode of exposure and recent development of sensing techniques.Berichte der deutschen chemischen Gesellschaft 03/2013; 2013(7):1086-1096. · 2.97 Impact Factor
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ABSTRACT: A new fluorescent sensor for the highly sensitive and selective determination of La3+ ion is developed. The sensing membrane was prepared by incorporating N,N′-bis(dansylamidoethyl)-N,N′-bis(2-pyridylmethyl)propylenediamine (L) as fluoroionophore in the plasticized PVC membrane containing o-NPOE as plasticizer. The proposed sensor displays a wide calibration range of 5.0 × 10−9 to 5.0 × 10−4 M with a low limit of detection of 2.0 × 10−9 M in a solution of pH 6.0. This sensor has a relatively fast response time of less than 2 min. In addition to high stability and reproducibility, it shows a unique selectivity toward La3+ ion with respect to common coexisting cations. The sensor can be regenerated by exposure to a solution of EDTA. The proposed sensor was successfully applied to the determination of La3+ in aqueous solutions.Sensors and Actuators 03/2014; B 192:378.
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ABSTRACT: A new sensor membrane based on a novel triazolo-thiadiazin derivative immobilized in polyvinyl chloride has been developed for the determination of Pb(II) ions that displays excellent performance. The parameters involved in the preparation of the optode and determination of Pb(II) were optimized. Under the optimal conditions, the proposed sensor displays a calibration response for Pb(II) over a wide concentration range of 5.0×10−8 to 3.8×10−4M with the detection limit of 2.2×10−8M. In addition to high reproducibility and reversibility of the fluorescence signal, the sensor also exhibits good selectivity over common metal ions. The optode membrane developed is easily prepared, stable, rapid, and simple for the determination of Pb(II). The accuracy of the proposed sensor was confirmed by analyzing standard reference materials of natural water and surface water. The sensor was successfully used for the determination of Pb(II) ions in water samples with satisfactory results.Sensors and Actuators B Chemical 09/2011; 157(1):162-168. · 3.84 Impact Factor