Colorimetric detection of Pb2+ ions using curcumin silver nanoparticles

The silver nanoparticles (AgNPs) complexed with curcumin (CUR) extracted from turmeric (TMR) were synthesized and applied for a simple and rapid colorimetric technique for Pb2+ detection. The results reveal that our low-cost and rapid AgNPs-CUR sensor is highly selective for Pb2+ ions with the detection limit of 13.6 mu M (2.8 mg.L-1) and can be applied for real water samples. Not only the observed absorption spectrum and the solution color can reveal the contamination of Pb2+ in the sample, but also an orange floccules precipitate can be clearly observed by naked-eye within 20 min. In addition, the results obtained from DFT calculation agree well with the experiments. Density functional theory (DFT), at the M06 level with mixed basis set of 6-31G(d) and def2-tzvp, was applied to propose the binding mechanism of AgNPs with CUR and AgNPs-CUR with Pb2+. Calculated binding energies of the compound of AgNPs with CUR and the AgNPs-CUR with Pb2+ are -145.8 and -361.4 kcal mol(-1), respectively, indicating that the AgNPs-CUR is strongly interact with Pb2+ ions through formation of highly stable Pb(2+)AgNPs-CUR complexes indicating the stable aggregative phenomena which agrees well with FTIR spectrum. (C) 2021 Elsevier B.V. All rights reserved.

Automated summary

The silver nanoparticles complexed with curcumin extracted from turmeric are effective for detecting lead ions, with high selectivity and rapid detection. Results can be observed naked-eye within 20 minutes and are in good agreement with experimental results.