Engineering carbon dots with a 18-crown-6 for the fluorescence detection of cadmium ions

Abstract

Carbon dots (CDs) with their bright photoluminescence represent a platform for the development of analytical sensors. In the context of sensing applications, there has been great interest in developing CD-based sensing platform for the detection of heavy metal ions in aqueous samples. Compared to other metals, the sensing of cadmium (II) ions using carbon dots-based system has been poorly investigated. This work details the use of CDs as fluorescent probes for the sensitive detection of cadmium (II) ions. We demonstrate that the rational engineering of the surface of the CDs though the post-synthetic modification with a crown ether increases the selectivity toward the analyte via the formation of a metal-crown complex. Using this sensor, Cd2+ ions could be determined in the range from 1.0 to120 µM with 0.05 µM as a detection limit. The hybrid material shows high selectivity for cadmium ions over other ions and was validated by determination of Cd+2 in (spiked) water samples to underpin its practicability.