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

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 13 nm for unmodified particles and, 30 nm 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 657 nM with an accuracy of the method of 0.13% (as RSD, n = 10) and sensitivity of 78 nM. 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 6-96 mu M with an accuracy of 2.5%. (C) 2015 Elsevier Inc. All rights reserved.