A novel composite of graphene quantum dots and molecularly imprinted polymer for fluorescent detection of paranitrophenol

• A eco-friendly composite of MIP-coated GQDs was fabricated for the first time.
• The fluorescent sensor was applied for the rapid detection of non-fluorescent 4-NP.
• The MIP-coated GQDs sensor was able to discriminate 4-NP from other similar phenols.
• Wide linear range and low detection limit of the MIP-coated GQDs sensor for 4-NP was obtained.

A novel fluorescent sensor based on graphene quantum dots (GQDs) was synthesized for determination of paranitrophenol (4-NP) in water sample, where molecularly imprinted polymer (MIP) was incorporated in GQDs-based sensing system for the first time. A simple hydrothermal method was used to fabricate silica-coated GQDs. The final composite was developed by anchoring the MIP layer on the silica-coated GQDs using 3-aminopropyltriethoxysilane as functional monomer and tetraethoxysilane as crosslinker. The combination of GQDs and MIP endows the composite with stable fluorescent property and template selectivity. Due to resonance energy transfer from GQDs (donor) to 4-NP (acceptor), the fluorescence of the MIP-coated GQDs composite can be efficiently quenched when 4-NP molecules rebound to the binding sites. The composite was applied to the detection of the non-emissive 4-NP and exhibited a good linearity in range of 0.02–3.00 µg mL−1 with the detection limit of 9.00 ng mL−1 (S/N=3). This work may open a new possibility for developing GQDs-based composite with selective recognition, and it is desirable for chemical sensing application.