Theoretical and experimental investigations of a gold nanosensor based on rhodamine-modified carbon nanotubes

A high selective nanosensor for metal ion sensing of rhodamine functionalized carbon nanotubes (CNT-RB) was successfully designed and synthesized. The complexation abilities of CNT-RB with metal ions including Cu3+, Hg3+, Al3+, and Au3+ ions were investigated using DFT calculations. The interactions between metal ions and CNT-RB were also investigated. The calculated results point out that CNT-RB displays the strongest complexation ability with Au3+ ion compared with Cu3+, Hg2+, and Al3+ ions. The electronic properties reveal that after CNT-RB forms complexes with Au3+, the energy gap of CNT-RB is clearly modified. Subsequently, the CNT-RB was synthesized via an amidation reaction of carboxylic acid functionalized carbon nanotubes (CNT-COOH) and rhodamine B-ethylenediamine (RB) in the addition of N-hydroxysuccinimide/1-ethyl-3-(3-dimethylaminopropyl)carbodiimide as coupling reagents. The sensitivity and selectivity of CNT-RB nanosensor to metal ions, i.e., Na+, Ag+ , Mg2+, Ca2+, Pb2+, Co2+, Ni2+, Cu2+, Zn2+, Pt2+,& nbsp;Hg2+, Cd2+, Al3+, Cr3+, Fe3+, Au3+, and Ru3+ ions were studied using the absorption and emission techniques. Experimental results are in good agreement with the computed results in which CNT-RB nanosensor displays high selectivity and sensitivity for Au3+ ion over the other metal ions. Therefore CNT-RB nanosensor could be applied as a naked-eye and fluorometric nanosensor for Au3+ ion detections. (C)& nbsp;2022 Elsevier B.V. All rights reserved.

Automated summary

A highly selective nanosensor, CNT-RB, was successfully designed and synthesized for metal ion sensing. The complexation abilities and interactions between CNT-RB and metal ions including Cu3+, Hg3+, Al3+, and Au3+ ions were investigated using DFT calculations. Experimental results showed that CNT-RB displayed high selectivity and sensitivity for Au3+ ion.