Bovine serum albumin coated CuInS2 quantum dots as a near-infrared fluorescence probe for 2,4,6-trinitrophenol detection

In this paper, a novel near-infrared fluorescence probe for the determination of 2,4,6-trinitrophenol (TNP) was developed based on bovine serum albumin (BSA) coated CuInS2 quantum dot (QD). Water-soluble CuInS2 QDs were directly synthesized in aqueous solution with mercaptopropionic acid (MPA) as stablizers, and it was coated by BSA via an amide link interacting with carboxyl of the MPA-capped CuInS2 QDs. The obtained BSA coated CuInS2 QDs (BSA-CuInS2 QDs) can bind TNP in water via the acid–base pairing interaction between electron-rich amino groups of BSA and electron-deficient nitroaromatic rings, and leading the fluorescence quenching of BSA-CuInS2 QDs. The quenched fluorescence intensity of BSA-CuInS2 QDs was proportional to the concentration of TNP in the concentration ranges from 50 nmol/L to 3.0 μmol/L. The detection limit (LOD) for TNP was 28 nmol/L. The developed fluorescence probe showed a excellent resistant to interference of metal ions such as K+, Na+, Zn2+, Cu2+, Hg2+, and Pb2+. The developed biosensor was applied to the determination of TNP in spiked water samples with satisfactory results.