Epicatechin coated silver nanoparticles as highly selective nanosensor for the detection of Pb2+in environmental samples

Abstract Epicatechin capped silver nanoparticles (ECAgNPs) were examined as sensor for Pb 2+ in blood and water samples. Several metal ions including Pb 2+ , Ca 2+ , Ni 2+ , Cd 2+ , Zn 2+ , Co 2+ , Hg 2+ , Cu 2+ , In 3+ , K + , Li + , Na + , NH 4 + , Cu + , Sn 2+ , Ba 2+ and Bi 3+ were screened. UV–visible spectra showed that only Pb 2+ enhanced absorption intensity (hyperchromic shift) at 412 nm whereas no other tested metal indicated any substantial change in the absorption spectra of ECAgNPs. Characterization of ECAgNPs-Pb 2+ complex through AFM showed spherical morphology, particle size measured through DLS was found to be 86.06 nm and Job ' s plot indicated 1:1binding stoichiometry of this complex. Whereas, ECAgNPs can selectively detect Pb 2+ in a concentration range of 1–100 μM with the detection limit down to 1.52 μM. Variation in pH from 1 to 12 showed that ECAgNPs-Pb 2+ complex is highly stable in basic medium. The results concluded on the basis of above mentioned techniques signifies remarkable selectivity of ECAgNPs for Pb 2+ over an extensive range of metal ions. Therefore, the synthesized ECAgNPs can successfully detect Pb 2+ in tap water and blood samples.