Fluorescent and colorimetric dual-mode detection of Cu based on carbon dots.

A fluorescent and colorimetric dual-mode strategy based on carbon dots (CDs) was rationally designed for sensitive determination of Cu. Green fluorescent CDs with high absolute quantum yield of 72.9% were synthesized by facile one-step hydrothermal treatment of triethylenetetramine and Rose Bengal. Cu could trigger the oxidative and chromogenic reaction of p-phenylenediamine (PPD) to generate chromogenic PPDox, accompanied by the fluorescence quenching of the CDs. The quenching mechanism was identified as the inner filter effect between PPDox and CDs. Therefore, a colorimetric/fluorescent dual-mode detection method for Cu recognition was constructed. The limits of detection for Cu were 4.14 μM and 1.28 μM for colorimetric and fluorescent mode, respectively. In addition, this method had achieved satisfactory results in the detection of Cu in real serum samples.