Upconversion nanoparticles/carbon dots (UCNPs@CDs) composite for simultaneous detection and speciation of divalent and trivalent iron ions

In this study, the application of carbon dots (CDs) modified NaYF4:Yb, Er nanoparticles (UCNPs@CDs) as the fluorescent nanoprobe for simultaneous detection of Fe2+ and Fe3+ was investigated. Fe3+ quanti-fication (5-80 mu mol L-1) was achieved, as a result of Fe3+ induced fluorescence quenching of UCNPs@CDs at 434 nm (under the 336 nm excitation). The chelate (Fe2+-phen) formed by Fe2+ and 1,10-phenanthroline had a broad absorption centered at 510 nm, due to inner filter effect (IFE), Fe2+ quantification (4-120 mu mol L-1) was achieved as a result of (Fe2+-phen) induced fluorescence quenching of UCNPs@CDs at 545 nm (under the 980 nm excitation). The resultant UCNPs@CDs probe, with excellent anti-interference capability, favorable fluorescence stability, and convincing performance in real sample analysis, showed promising application in simultaneous detection of Fe2+ and Fe3+. (C) 2021 Elsevier B.V. All rights reserved.