Synthesis of β-cyclodextrin functionalized gold nanoparticles for the selective detection of Pb²⁺ ions from aqueous solution

Abstract

In the present study we carried out the synthesis of β-cyclodextrin (β-CD) functionalized gold nanoparticles (AuNPs) using a microwave assisted heating method in alkaline media. Stable dispersion of β-CD stabilized AuNPs was obtained at an optimized pH of 10.5. At this pH value the deprotonated secondary hydroxyl group of β-CD shows the highest chelating affinity toward Pb²⁺ ions thereby inducing AuNP aggregation. The Pb²⁺ induced aggregation in β-CD-AuNP solution is monitored by both colorimetric response and UV-Vis spectroscopy. TEM, DLS and FTIR analyses were carried out to confirm the Pb²⁺ ion induced aggregation behaviour of β-CD-AuNPs under alkaline conditions. Furthermore at the experimental pH the response of the β-CD-AuNP system towards Pb²⁺ ions is selective when compared with other interfering metal cations.

Keywords

gold nanoparticle (AuNP) / β-cyclodextrin (β-CD) / colorimetric detection / metal ion