DNA-AgNCs as a fluorescence turn-off probe for dual functional detection of H2O2 and Fe(II) ions

Abstract A novel fluorescence probe (DNA-AgNCs) was synthesized for dually detecting hydrogen peroxide (H2O2) and ferrous ion (Fe(II)) in water samples. The assay is carried out through a dramatic “turn-off” fluorescence response of AgNCs by hydroxyl radical ( OH), which is produced when H2O2 and Fe(II) are present simultaneously. Under the optimal conditions, the degree of fluorescence quenching of the DNA-AgNCs at 525 nm is linearly related to the concentration of H2O2 in the range of 0.3 to 450 pM, and Fe(II) in the range of 0.2 to 6.0 μM. The limit of detection (LOD) of H2O2 and Fe(II) are as low as 99 fM and 60 nM, respectively. Moreover, this method has the advantages of good specificity, high sensitivity, and can be successfully applied for detecting H2O2 and Fe(II) in the real water samples.