کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
606977 | 1454552 | 2015 | 6 صفحه PDF | دانلود رایگان |
• Calculated pH of AgNPs solutions was found in agreement with the experimental one.
• The AgNPs exhibit enantiodiscrimination properties towards underivatized amino acids.
• The role played by pH was investigated by using thermodynamic stability constants.
Stereoselective amino acid analysis is still a challenging task. In this work, we report a study on the chiral recognition of d,l-Trp and d,l-His using l-Cys capped silver nanoparticles (AgNPs) and copper(II) ion. The AgNPs have been characterized by TEM, UV–Vis spectra and dynamic light scattering (DLS) measurements and used for chiral discrimination. In the l-Cys capped AgNPs, the α-amino and α-carboxyl groups of the surface-confined amino acid, besides showing either a negative or a neutral charge as a function of the pH, can coordinate the copper(II) ion, which in turn, binds the l- or d-amino acid present in solution forming diastereoisomeric complexes. The resulting systems have been characterized by UV–Vis spectroscopy, exploiting the zwitterionic nature of the cysteine to obtain enantiodiscrimination by a fine tuning of the pH. The analysis of the UV–Vis data by using a multiwavelength approach allows us to determine the kinetic constants ruling the processes.
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Journal: Journal of Colloid and Interface Science - Volume 443, 1 April 2015, Pages 30–35