Colorimetric Detection of Pb2+ Using Glutathione Functionalized Gold Nanoparticles

A facile, cost-effective and sensitive colorimetric detection method for Pb2+ has been developed by using glutathione functionalized gold nanoparticles (GSH-GNPs). The sensitivity and selectivity of detection were investigated in detail. The GSH-GNPs could be induced to aggregate immediately in the presence of Pb2+, especially after the addition of 1 M NaCl aqueous solution. The Pb2+ could be detected by colorimetric response of GNPs that could be monitored by a UV vis spectrophotometer or even naked eyes, and the detection limit could reach 100 nM. The GSH-GNPs bound by Pb2+ showed excellent selectivity compared to other metal ions (Hg2+, Mg2+, Zn2+, Ni2+, Cu2+, Co2+, Ca2+, Mn2+, Fe2+, Cd2+, Ba2+, and Cr3+), which led to prominent color change. This provided a simple and effective colorimetric sensor (no enzyme or DNA) for on-site and real-time detection of Pb2+. Most importantly, this probe was also applied to determine the Pb2+ in the lake samples with low interference and high sensitivity.