Lysine and dithiothreitol promoted ultrasensitive optical and colorimetric detection of mercury using anisotropic gold nanoparticles

Abstract

Using lysine (Lys) and dithiothreitol (DTT) as aggregation promoters, an ultrasensitive and highly selective colorimetric assay for detection of mercury (Hg²⁺) ions has been developed with anisotropic gold nanoparticles (GNP). The detection limit of the assay is determined to be 27 pM and 58 pM for Hg²⁺ in deionized water and tap water, respectively. The mechanism of sensing is explained on the basis of possible mercury-gold amalgam formation and subsequent aggregation of the GNP upon addition of Lys and DTT. The kinetics data indicate that the sensor can be effectively used for on-site and real-time Hg²⁺ detection.