Colorimetric and fluorescent detection of glucose based on Fe7S8 nanosheets catalyzed oxidation of o-phenylenediamine.

[Display omitted] • Fe 7 S 8 NSs with peroxidase-like activity was prepared by hydrothermal method. • A colorimetric and fluorescence dual-signal method was developed for determining glucose. • The method exhibited excellent sensitivity and high selectivity. Fe 7 S 8 nanosheets (Fe 7 S 8 NSs) was prepared from ferrous sulfate and thiourea, showing peroxidase-like activity and enabling the oxidation of o-phenylenediamine (OPD) in the presence of H 2 O 2 to produce 2,3-diaminophenol (DAP) with strong absorption and fluorescence peaks at 450 and 560 nm, respectively. Furthermore, both the level of absorbance at 450 nm (A 450) and the intensity of fluorescence at 560 nm (F 560) depended on the concentration of H 2 O 2. As a result, a dual response (colorimetry and fluorescence) method for the assay of H 2 O 2 was established. Due to the fact that H 2 O 2 can be produced from glucose oxidase catalyzed glucose oxidation, A 450 and F 560 were further used for indirect determination of glucose. The results indicated that the absorbance and fluorescence responses were closely related to glucose concentration in the range of 1.0–100 μM and 1.0––70 μM with the detection limit of 0.83 and 0.52 μM, respectively. To verify its practicality, the method has been used for determining glucose in human serum samples with recoveries ranging from 92.2 to 106.2 %, suggesting its promising potential applications. [ABSTRACT FROM AUTHOR]