Javad Tashkhourian - Department of Chemistry, Faculty of Sciences, Shiraz University, Shiraz, ۷۱۴۵۴, Iran
Omid Sheydaei - Department of Chemistry, Faculty of Sciences, Shiraz University, Shiraz, ۷۱۴۵۴, Iran

A selective, simple and low-cost method for the colorimetric determination of Fe۳+ ions based on chitosan capped silver nanoparticles (Chit-AgNPs) was presented. Chitosan is a cationic polyelectrolyte and possesses amino and hydroxy groups which make it widely used as a capping agent for Ag NPs. The synthesized chitosan capped silver nanoparticles with excellent colloidal stability were characterized by UV–Visible spectrometry, transmission electron microscopy, Fourier transform infrared, X-ray diffraction. Chit-AgNPs exhibit a strong surface plasmon resonance band which disappears in the presence of increasing concentrations of Fe۳+ ions. This system showed a visually detectable color change from brownish-yellow to colorless for the selective determination of Fe۳+. The method can be applied for the determination of Fe۳+ ions in the concentration range of ۱.۰×۱۰-۶ to ۵.۰×۱۰-۴ M. The detection limit was determined from three times the standard deviation of the blank signal (۳σ/slope) as ۵.۳ × ۱۰−۷ M. The developed method was successfully applied for the determination of Fe۳+in real samples

Chitosan capped silver nanoparticles, Colorimetric determination, Iron(III) ion