EDTA-capped gold nanoparticles as a colorimetric probe for aluminium

作者：Diamai Siewdorlang; Negi Devendra P S^*

来源：Materials Research Express, 2016, 3(11): 115002.

DOI：10.1088/2053-1591/3/11/115002

• aggregation
• nanoparticles
• detection
• capping agent

Gold nanoparticles (AuNPs) have been synthesized using ethylenediaminetetraacetic acid (EDTA) as a capping agent. Transmission electron microscopy measurements showed the particles to have an average size of similar to 40 nm. The absorption spectrum of the AuNPs displayed a sharp absorption band at 523 nm. The red colloidal solution of the AuNPs was found to immediately change its colour to blue upon addition of 20 mu m Al3+ ions. The addition of the same concentration of Cr3+ ions resulted in the same colour change but only after similar to 5 min. No colour change was observed on addition of the same concentrations of Fe3+, Cu2+, Pb2+, Cd2+, Zn2+, Co2+, Ni2+, Hg2+ and Mn2+ ions. The colour change was attributed to the aggregation of the AuNPs due to complexation of the Al3+ ions by EDTA on the AuNPs. This was supported by dynamic light scattering data. A plot of the ratio of the extinctions at 700 and 523 nm versus the Al3+ ion concentration was linear in the 2-18 mu m range and the limit of detection was 3.6 mu m.

• 出版日期2016-11