Diaminodiphenyl sulfone as a novel ligand for synthesis of gold nanoparticles for simultaneous colorimetric assay of three trivalent metal cations (Al3+, Fe3+ and Cr3+)

Abstract

A novel ligand namely diaminodiphenyl sulfone (DDS) is introduced for the fabrication of gold nanoparticles (AuNPs) without use of external reducing agent. Various parameters (reagents concentrations and time) were investigated for the fabrication of DDS-AuNPs with controlled size and color. The DDS ligand chemistry on AuNPs plays a vital role to act AuNPs as three trivalent metal cations sensor i.e., Al3+, Fe3+ and Cr3+. By modifying the surface chemistry of AuNPs with DDS, DDS-AuNPs acted as trivalent metal ions sensor, resulting a drastic plasmonic shift in the absorption spectra and change in color from red to blue. The spectroscopic and electron microscopic data revealed that three metal ions (Al3+, Fe3+ and Cr3+) were greatly induced the spectral shifts and morphological changes in the DDS-AuNPs, demonstrating the aggregation of DDS-AuNPs. Rapid colorimetric assay of three metal ions (Al3+, Fe3+ and Cr3+) is achieved in the wider range (1.0–500 μM) and the detection limits of DDS-AuNPs sensor were 0.62, 0.69 and 0.78 μM for Al3+, Fe3+ and Cr3+ ions, respectively. Moreover, this method possessed quantitative detection ability for three metal ions (Al3+, Fe3+ and Cr3+) with good recognition, and reproducibility, representing great potentiality in assaying of three metal ions in real samples (river, tap and canal water).