Highly fluorescent organic polymers for quenchometric determination of hydrogen peroxide and enzymatic determination...

Strongly fluorescent polymers (FPs) were prepared from citric acid and ethylenediamine via a hydrothermal approach. The FPs display low toxicity, water solubility, a quantum yield of 91%, good photostability and stability in the physiological pH range. Ferric ions are found to quench the fluorescence which is best measured at excitation/emission wavelengths of 350/440 nm. Because ferric ions (Fe³⁺) can quench the fluorescence of FPs, a fluorometric method was developed for fast detection of Fe³⁺ and within 1 min. FPs can also be used indirectly for the detection of hydrogen peroxide because of its fast Fenton reaction with Fe²⁺ to generate of Fe³⁺. The detection limits are 8 μM for Fe(III) and 0.6 μM for H₂O₂. On the basis of the glucose oxidase catalyzed of glucose and the Fenton reaction, the FPs can also be used to quantify glucose with a linear response in the 0.5-10 μM concentration range. Graphical abstract A new type of polymer with high fluorescence quantum yield was prepared. It is shown to enable the fast detection of ferric ions, hydrogen peroxide and glucose based on quenching and on the glucose oxidase and Fenton reactions.