Fluorometric methods for determination of HO, glucose and cholesterol by using MnO nanosheets modified with 5-carboxyfluorescein.

A fluorescent probe for HO is described. It is composed of MnO nanosheets and 5-carboxyfluorescein and was characterized by fluorescence, transmission electron microscopy, ultraviolet-visible absorption spectra, energy dispersive X-ray and Fourier transform infrared spectroscopy. The probe, with fluorescence excitation/emission maxima at 490/518 nm, responds to HO in the 1 to 200 μM concentration range and has a 0.33 μM detection limit. The probe was used in enzymatic assays for glucose and cholesterol by using the respective oxidases which produce HO. Responses are linear in the concentration range from 0.5 to 200 μM in case of glucose, and from 1 to 300 μM in case of cholesterol. The method was applied to quantify glucose and cholesterol in (spiked) serum samples. Graphical abstract Schematic presentation of the principle based on hydrogen peroxide-induced degradation of MnO nanosheet-FAM complex for detection of HO (a), glucose and cholesterol (b).