Colorimetric and rapid determination of Cr(III) ions in water samples using AuNPs modified with 11-mercaptoundecyl phosphonic acid: spectroscopic characterization and reaction mechanism

Abstract

A facile colorimetric method for rapid determination of Cr(III) ions was developed using 11-mercaptoundecylphosphonic acid modified gold nanoparticles (AuNPs-MPA) in aqueous medium. The reaction of AuNPs-MPA + Cr(III) ions were were characterized by FTIR and Uv-Vis spectroscopy. The presence of Cr(III) easily induced aggregation of AuNPs-MPA, resulting in the color change from pink to blue. This method exhibited excellent selectivity toward Cr(III) compared to other metal cations. Optimal detection of Cr(III) was found in a pH range from 4 to 9, the detection time within 8 min. In addition, the developed effective probe has been successfully applied to detect Cr(III) water samples.

Keywords:

• AuNPs
• chromium
• SEM–EDS mapping
• UV–vis–IR characterization
• water samples

Acknowledgements

The authors gratefully acknowledge access to the analytical facilities (Transmission Electronic Microscopy Laboratory) at the Centro de Nanociencias y Nanotecnología, Universidad Nacional Autónoma de México (CNyN-UNAM).

Additional information

Funding

B.A.G.G. thanks the support from Consejo Nacional de Ciencia y Tecnología (CONACYT) in the form of a graduate scholarship (261564). This work was supported by Secretaría de Educación Pública México (UAS-CA-281). The authors are grateful to the Supramolecular Chemistry Thematic Network (Grant. No. 281251) for their support.