Selective determination of Cr (III) by new designed optical sensor based functionalized gold nanoparticles

A new, selective and sensitive chemical optical sensor based on Au nanoparticles stabilized with polyvinylalcohol (PVA) and functionalized with congo red (CR) (Au-NPs-PVA-CR) was prepared and applied for determination of trace amount of Cr (III) ion in aqueous media. The Au-NPs-PVA-CR sensor was characterized via FESEM, XRD, FT-IR and EDS analysis. All used materials for proposed sensor were non-toxic, biodegradable and have been many medical applications. The Au-NPs-PVA-CR sensor exhibited a linear range of2.2621–23.0769µg mL-1 for Cr (III) ion concentration with a detection limit of 0.7609 µg mL-1. The response and life time for the Au-NPs-PVA-CR designed sensor were found to be 60 s and 1 month, respectively. The Au-NPs-PVA-CR sensor showed very good selectivity for Cr (III) ions in presence of Cu2+, Pb2+, Co2+, Ag+, etc. The Au-NPs-PVA-CR sensor was shown the good repeatability and reproductability with relative standard deviation (R.S.D.) of 4.044% and 3.535 % for repeatability and reproductability, respectively. Finally, the developed Au-NPs-PVA-CR sensor successfully was applied to determine the Cr(III) ions in real water samples with spiked method [1-3].