Upconversion luminescence detection of ascorbic acid based on NaGdF4:Yb,Er@NaYF4 nanoparticles and oxidase-like CoOOH nanoflakes

In this work, we developed a simple and selective luminescence sensing system for detecting ascorbic acid (AA) based on NaGdF4:Yb,Er@NaYF4 upconversion nanoparticles (UCNPs) and oxidase-like CoOOH nanoflakes. When p-phenylenediamine (PPD) and oxidase-like CoOOH nanoflakes were added to the UCNPs solutions, PPD, as a typical substrate of oxidase, could be oxidized to PPDox. The luminescence intensity of UCNPs was quenched because PPDox could play a role as an energy acceptor. When AA was added to the above solution mixture, the CoOOH nanoflakes were destroyed, and then, the luminescence intensity was recovered. Under the best experimental conditions, the linear range for detection of AA was 0.8 to 280 μM, and the detection limit was 0.25 μM. Furthermore, the system could be applied to real sample analysis with satisfactory results.