Development of a novel tridentate ligand for colorimetric detection of Mn2+ based on AgNPs

A novel tridentate ligand nitrilotris(methylene)tris(1,2,3-triazole)triacetate (NTTTA) has been synthesized by click reaction and followed with ester hydrolysis reaction. The silver nanoparticles (AgNPs) were then modified and stabilized by this ligand, and subsequently been employed for the highly selective and sensitive colorimetric detection of Mn2+ in aqueous solution. The presence of Mn2+ can cause the aggregation of AgNPs, which leads to the color change of the dispersion from yellow to brown, as well as the decrease and red-shift of the surface plasmon resonance absorption. The detection limit of Mn2+ was as approximately 0.5 mu M by the naked eyes. UV-vis spectroscopy analysis showed a good linear relationship between the logarithm of the ratios (A(550)/A(395)) and the concentration of Mn(2+)over the range of 0.05 mu M-10 mu M, and the LOD was calculated to be 12.6 nM (S/N = 3). The present assay showed good simplicity without the need of adjusting the pH value. The feasibility of this technique was evaluated for successful detection of Mn2+ in tap water and lake water samples, with good recoveries. (C) 2018 Elsevier B.V. All rights reserved.