Ratiometric and selective fluorescent sensor for Fe(III) and bovine serum albumin based on energy transfer

A facility fluorescent sensor was fabricated for highly selective and sensitive detection of Fe3+ relying on red emissive carbon dots (RCDs) used as the target sensitive fluorophore. Fluorescence quenching are attributed to the strong coordination interaction between the target ions and the phenolic hydroxyl groups on the surface of RCDs. Interestingly, the fluorescent nanoprobe also showed great potential in detection of bovine serum albumin (BSA), attributed to the existence of Fe3+ ions. Serum albumins are the most abundant proteins spreaded throughout the circulatory system of all kinds of organisms, which play a crucial role in the process of metabolism. More importantly, the ratiometric fluorescent probe is easy to fabricate by mixturing blue emissive carbon dots (BCDs) with RCDs together, the fluorescence intensity of RCDs can be obviously quenched by Fe3+ ions or BSA under a single excitation wavelength, but that of BCDs is weakly changed, leading to the ratiometric fluorescence response with a good linear wider range of 0–400 μM and 0–320 μM, respectively. This ratiometric probe has also successfully been applied in real samples, that are cow urine and lake water, and observed to be almost no interference in the detection of Fe3+ ions.