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A MnO2 nanosheet-based ratiometric fluorescent nanosensor with single excitation for rapid and specific detection of ascorbic acid
- Lyu, Yanlong, Tao, Zhanhui, Lin, Xiaodong, Qian, Pengcheng, Li, Yunfei, Wang, Shuo, Liu, Yaqing
- Analytical and bioanalytical chemistry 2019 v.411 no.18 pp. 4093-4101
- ascorbic acid, beverages, blood serum, cost effectiveness, dehydroascorbic acid, detection limit, false positive results, fluorescence, human health, manganese, manganese dioxide, nanosheets, oxidation, sensors (equipment), wavelengths
- Ascorbic acid (AA) detection in biological sample and food sample is critical for human health. Herein, a MnO₂ nanosheet (MnO₂-NS)-based ratiometric fluorescent nanosensor has been developed for high sensitive and specific detection of AA. The MnO₂-NS presents peroxidase-like activity and can oxidize non-fluorescent substrate of o-phenylenediamine (OPDA) into fluorescent substrate, presenting maximum fluorescence at 568 nm (F₅₆₈). If MnO₂-NS is premixed with AA, the MnO₂-NS is then decomposed as Mn²⁺ by AA, decreasing the fluorescent intensity of F₅₆₈. Meantime, AA is oxidized as dehydroascorbic acid (DHAA), which can react with OPDA to generate fluorescent substrate. A new fluorescence response is found at 425 nm (F₄₂₅). The dual fluorescent responses can be excited with a universal excitation wavelength, simplifying the detection procedure. With F₄₂₅/F₅₆₈ as readout, limit of detection for AA reaches as low as 10.0 nM. Satisfactory recoveries are found for AA detection in serum and diverse beverages. The ratiometric strategy significantly eliminates false-negative and false-positive results, providing a cost-effective, rapid, and reliable way for AA detection in real sample.