Lead (II) ion detection in surface water with pM sensitivity using aza-crown-ether-modifiedsilver nanoparticles via dynamic light scattering

Abstract

In this paper, we reported ultrasensitive lead ion detection in environmental water with pMsensitivity using aza-crown-ether-modified silver nanoparticles (ACE-Ag NPs) through dynamiclight scattering (DLS). The colorimetric method based on ACE-Ag NPs is not capable of detectingPb2 + ions over othermetal ions (Fe3 + , Co2 + ,Cu2 + ,Hg2 + ,Cd2 + ,Ag + ,Li + ,Na + ,K + andCs + ) with high sensitivity. But DLS has improved the selectivity and sensitivity of thePb2 + detectionsystem (50-fold or more) over colorimetric method, and its detection limit is 0.25 pM (1.03 ppt). ThePb2 + DLS assay can beapplied to detect Pb2 + in the environmental water, such as in Yangtze and East Lake water samples with a detectionlimit of 0.20 and 0.22 pM, which is much lower than the maximum contamination level of4.8 × 10 − 8 M for lead in surface water defined by the national environmental quality standards ofChina (GB 3838-2002). Also, this method has a good performance in the determination ofPb2 + in drinking water, which is much lower than the maximum contamination level (MCL) of72 nM for lead as defined by the US Environmental Protection Agency (EPA).