Development of an Optode for Detection of Trace Amounts of Hg~(2+) in Different Real Samples Based on Immobilization of Novel Tetradentate Schiff Bases Bearing Two Thiol Groups in PVC Membrane

摘要

A very sensitive and reversible optical chemical sensor based on a novel tetradentate Schiff base namely N.N/bis(2-aminothiophenol)benzene-1,2-dicarboxaldehyde (ATBD) immobilized within a plasticized PVC film for Hg~(2+) determination is described. At optimum conditions (i.e. pH 6.0), the proposed sensor displayed a linear response to Hg~(2+) over 1.0×10~(-10) - 1.0×10~(-2) mol L~(-1) with a limit of detection of 7.23×10~(-11) mol L~(-1) (0.0145 μgL~(-1)). Moreover, the results revealed that, under batch condition, the sensor is fully reversible within a response time~35 s. In addition to its high stability and reproducibility, the sensor showed good selectivity towards Hg~(2+) ion with respect to common metal cations. The sensor was successfully applied for determination of Hg~(2+) ion in some real samples, including hair, urine and well water samples. The results were in good correlation with the data obtained using cold vapor atomic absorption spectrometry.