p-Dimethylaminobenzaldehyde thiosemicarbazone: A simple novel selective and sensitive fluorescent sensor for mercury(II) in aqueous solution

A novel and simple fluorophore, p-dimethylaminobenzaldehyde thiosemicarbazone (DMABTS), was prepared in order to find available fluorescent chemosensor for mercuric ion in aquesous solution. DMABTS emitted fluorescence at 448 nm in aqueous solution and its fluorescence intensity was completely quenched upon interaction with Hg2+ ions, which should be attributed to the 1:1 complex formation between DMABTS and Hg2+. The binding constant of the complex was determined as 7.48 × 106 mol l−1. The linear range of quantitative detection of 0 to 5.77 × 10−6 mol l−1 and the detection limit of 7.7 × 10−7 mol l−1 for Hg2+ in the 6.3 × 10−6 mol l−1 DMABTS aqueous solution were obtained from a calibration curve. The coexistence of several transition metal ions and anions did interfere the fluorometric titration of Hg2+ ion by less than 4% in the emission change.