Carbon dots on based folic acid coated with PAMAM dendrimer as platform for Pt(IV) detection

[Display omitted] •Fluorescent Carbon dots coated with PAMAM-NH2 (CQDs@PAMAM-NH2) based on folic acid.•Characterized by DLS, TEM, XPS, ATR, Raman and fluorescence techniques.•Quenching by the unreacted Pt(IV) as (PtCl6)2− proposed an analytical method.•The static mechanism was demonstrated by fluorescence lifetime analysis.•A wide range of interferences studied make suitable for a sensitivity of 78nM. Carbon quantum dots (CQDs) coated with poly(amidoamine) (PAMAM-NH2) dendrimer are prepared from folic acid and phosphoric acid under a hydrothermal procedure. The obtained nanoparticles are successfully used as fluorescent sensor for Pt(IV) (in the form of chloroplatinate ion). CQDs possess many attractive features including uniform dispersion with average size about 13nm for unmodified particles and, ∼30nm when they are coated with PAMAM-NH2 dendrimer. The synthesized nanoparticles have been characterized by elemental analysis, attenuated total reflectance (ATR), X-ray photoelectron (XPS) and Raman spectroscopies, transmission electron microscopy (TEM), dynamic light scattering (DLS), and steady-state and life-time fluorescence. CQDs are used as fluorescent sensor of Pt(IV) ion in aqueous media showing linear quenching effect of their fluorescence. The results obtained demonstrated a limit of detection of 657nM with an accuracy of the method of 0.13% (as RSD, n=10) and sensitivity of 78nM. Moreover, with the presence of other interference species, good results are obtained when applied in real samples from platinum nanoparticles synthesis. The dissolved platinum ions can be quantified in the range 6–96μM with an accuracy of 2.5%.