Sharif University of Technology Scientia Iranica 1026-3098 17 2 2010 04 01 A Sensitive Colorimetric Detection of Ascorbic Acid in Pharmaceutical Products Based on Formation of Anisotropic Silver Nanoparticles 3385 EN Mohammad Reza Hormozi Nezhad Department of Chemistry,Sharif University of Technology M.A. Karimi Department of Chemistry,University of Leeds Fatemeh Shahheydari Department of Chemistry,University of Kerman Journal Article 2011 01 24 A sensitive colorimetric method for the detection of ascorbic acid was proposed in this research based on the reduction of silver ions by ascorbic acid in the presence of citrate-stabilized silver seeds, additional trisodium citrate and a polymer such as polyvinylpyrrolidone. The color of the stable sol is controlled by varying the concentration of trisodium citrate (TSC), polyvinylpyrrolidone, silver nitrate and silver seeds. The reduction of Ag+ to triangle silver nanoparticles (Ag-NPs) by ascorbic acid in the presence of trisodium citrate (TSC) and silver seeds produced two very intense surface plasmon resonance peaks of Ag-NPs. The plasmon absorbance of Ag-NPs allows the quantitative spectrophotometric detection of the ascorbic acid. The calibration curve derived from the changes in absorbance at  = 427 nm was linear, with the concentration of ascorbic acid in the range of 6:010????6 to 8:010????5 M. The method was applied to the determination of ascorbic acid in pharmaceutical formulations with satisfactory results. https://scientiairanica.sharif.edu/article_3385_6a3e1c430a9cd99b4be7a38bb859bcf3.pdf