2,3-Pyridine dicarboxylic acid functionalized gold nanoparticles: Insight into experimental conditions for Cr3+sensing.
Selectivity of gold nanoparticles (AuNPs) depends upon surface functionality; small changes in structure or concentration bring significant changes in the behavior of AuNPs. In this study, citrate-capped AuNPs were functionalized with ortho-dicarboxylate substituted pyridine (2,3-PDCA) and detailed studies on experimental conditions were carried out to check the stability of AuNPs and response for Cr3+. Stability of PDCA-AuNPs was found sensitive to the pH, ionic strength of buffer and its type. Capping behavior of PDCA on C-AuNPs was examined by FTIR spectroscopy. Surface morphology and size of synthesized AuNPs were confirmed by AFM, XRD, and DLS techniques where particles were found 11nm in size, monodisperse and spherical in shape. Interaction of stabilized AuNPs was tested with various metal ions; where Cr3+induced the changes in localized surface plasmon band (LSPR) of PDCA-AuNPs which leads to a color change from wine red to violet blue. The phenomenon is explained as cooperative effect of citrate and pyridine nitrogen on surface of AuNPs in contrary to meta-dicarboxylate substituted pyridine derivatives. Further, under optimized and controlled conditions Cr3+shows linear response with decrease in absorbance at LSPR intensity of AuNPs (518nm). Moreover, to demonstrate the applicability of method, Cr3+was determined in the presence of Cr (VI) which shows 96% recovery.
National Centre of Excellence in Analytical Chemistry, University of Sindh, Jamshoro, Pakistan.
Ruqaya
R
Shaikh
National Centre of Excellence in Analytical Chemistry, University of Sindh, Jamshoro, Pakistan. Electronic address: najmamemon@gmail.com.
Najma
N
Memon
National Centre of Excellence in Analytical Chemistry, University of Sindh, Jamshoro, Pakistan.
Amber R
AR
Solangi
National Centre of Excellence in Analytical Chemistry, University of Sindh, Jamshoro, Pakistan.
Huma I
HI
Shaikh
Centre for Pure and Applied Geology, University of Sindh, Jamshoro, Pakistan.
Muhammad Hassan
MH
Agheem
H. E. J. Research Institute of Chemistry, International Center for Chemical and Biological Sciences, University of Karachi, Karachi 75270, Pakistan.
Syed Abid
SA
Ali
H. E. J. Research Institute of Chemistry, International Center for Chemical and Biological Sciences, University of Karachi, Karachi 75270, Pakistan.
Muhammad Raza
MR
Shah
Dr. M.A. Kazi Institute of Chemistry, University of Sindh, Jamshoro, Pakistan.
Aftab
A
Kandhro
2,3-Pyridine dicarboxylic acid; Chromium speciation; Functionalized gold nanoparticles; Ionic strength of buffer; Localized surface plasmon resonance sensor; Trivalent chromium