A reversible redox-fluorescence switch based on Prussian blue and carbon quantum dots for dual-spectral detection of N2H4 and H2O2

Abstract

Hydrazine hydrate and hydrogen peroxide are both important raw materials for industrial production and have a wide range of applications in several fields. Owing to their damage to the human body and cellular functions by excessive exposure or ingestion, it is essential to develop an efficient and rapid assay for the detection of hydrazine hydrate and hydrogen peroxide. Fluorescence switches have been applied in many fields including for metal ion detection. However, the assembly of Prussian blue (PB) and carbon quantum dots (CDs) has never been reported for the fabrication of a fluorescence switch for the detection of hydrazine and hydrogen peroxide. In this work, a fluorescent switch PB@CD/SiO₂ based on PB and CDs was constructed, which could be used as a detection platform for hydrazine hydrate and hydrogen peroxide. The surface of PB was coated with a silica layer, which contained CDs to fabricate PB@CD/SiO₂ nanoparticles. The composite demonstrated reversible switching between fluorescence quenching and recovering states through the mutual conversion of PB and Prussian white (PW). The prepared composite was utilized for the detection of N₂H₄ and H₂O₂ by fluorescence spectroscopy and UV-vis absorption spectroscopy. It is worth-mentioning that the detection limit for N₂H₄ is calculated to be 0.15 μM (fluorescence) and the detection limit for H₂O₂ can reach 0.93 μM (UV). Moreover, both detection methods showed low detection limits, wide detection ranges and a short response time for N₂H₄ and H₂O₂. The proposed fluorescence switch system exhibits good performance towards the dual-spectral determination of hydrazine and hydrogen peroxide by fluorescence spectroscopy and UV-vis spectroscopy, which may be beneficial for further application in practical fields.