Polyvinylalcohol-citrate-stabilized gold nanoparticles supported congo red indicator as an optical sensor for selective colorimetric determination of Cr(III) ion

Abstract A selective and sensitive chemical optical sensor was prepared based on citrate capped gold nanoparticles growth in polyvinyl-alcohol (PVA) holding matrix and congo red (CR)-functionalized (PVA-Au-Citrate-NPs-CR), while consequently applied for the determination of trace amount of Cr(III) ion in aqueous media. Polyvinyl alcohol and trisodium citrate as a processor of Gold nanoparticles have the safest NFPA 704 so there is not any toxicity for using them in any condition including biological samples. The PVA-Au-Citrate-NPs-CR sensor was characterized via UV–Vis, SEM, DLS, XRD, FTIR, and EDS. At best operational conditions, an understudy sensor applied for monitoring the Cr(III) ion over 8.06 × 10−6–5.26 × 10−5 mol L−1 with a detection limit of 2.418 × 10−6 mol L−1. The present sensor has an acceptable response time as fast as 60 s with high stability over 1 month. The PVA-Au-Citrate-NPs-CR sensor is highly selective for Cr(III) ion in the presence of Cu2+, Pb2+, Co2+, Ag+, etc with good repeatability and reproducibility and satisfactory relative standard deviation (R.S.D) (less than 4.044% and 3.535%, respectively). Finally, the developed PVA-Au-Citrate-NPs-CR sensor is used for Cr(III) ion in different real water and green tee samples and in all situations, their accuracy was checked using recovery and RSD.