A carbon dot based biosensor for melamine detection by fluorescence resonance energy transfer

• Amino-functionalized carbon dots have been used for detecting melamine.
• Melamine is analyzed with a wide linear range and a low detection limit.
• The method is verified by detecting melamine in milk powder and raw milk with satisfactory recoveries.
• This method does not require any complicated modifications and expensive instrumentation.

In this paper, we constructed a fluorescence resonance energy transfer (FRET) system between amino-functionalized carbon dots (C-dots) and gold nanoparticles (AuNPs). In this system, C-dots were treated as energy donors, while AuNPs were treated as energy acceptors. We optimized some important factors including incubation time, AuNPs concentration and media pH, which would affect the efficiency of the FRET system. Under the optimized experimental conditions, melamine could be detected based on fluorescence intensity of C-dots. We could get a linear relationship between 50 nM and 500 nM and the detection limit was 36 nM. The proposed method was applied to the determination of melamine in milk samples with satisfactory results. Compared with previous reports, the proposed method manifested great advantages including high sensitivity, short analysis time, low cost and ease of operation.

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