Green synthesis of cow milk-derived carbon quantum dots and application for Fe3+ detection

A fast and efficient fluorescent probe based on carbon quantum dots (CQDs) was studied to detect ferric ions (Fe3+) in tap water. Cow milk-derived carbon quantum dots (CMCQDs) were synthesized via hydrothermal method using milk as the carbon source. The size, morphology, surface composition, optical properties and stability of the CMCQDs were fully characterized. The obtained CMCQDs show blue fluorescence, uniform distribution, small particle size and excellent fluorescence stability. There is a specifically quenching effect on CMCQDs by Fe3+, so the CMCQDs can be employed as a fluorescence probe for determination of Fe3+ with high selectivity and sensitivity. The limit of detection (LOD) is 0.6 mu mol/L in the range of 0.1-20 mu mol/L (R-2 = 0.9911). Herein, the fluorescent quenching of CMCQDs is thought to result from the by the unique chelation or coordination between Fe3+ and surface functional groups of CMCQDs. The sensitive and selective fluorescent probe was confirmed to demonstrate high potential in Fe3+ detection in tap water.