Fluorometric/electrochemical dual-channel sensors based on carbon quantum dots for the detection and information anti-counterfeiting

• The quantum yield of CQDs was up to 52.64%. • The prepared CQDs can be used for the rapid detection of Fe 3+ and Cys using fluorescent and electrochemical dual-channel probes. • The LOD obtained by the two channels is basically the same. Sensors used to detect Fe 3+ and Cys are generally a single method. In this work, two methods of fluorescence and electrochemistry are innovatively combined to detect Fe 3+ and Cys, and the obtained Lod is basically the same. Carbon quantum dots (CQDs) with blue fluorescence were successfully prepared by hydrothermal methods using tryptophan (Trp) as carbon source, which can be used for fluorescence and electrochemical dual-channel probe quickly detecting iron ion (Fe 3+ ) and cysteine (Cys). A series of studies have been carried out on its morphology, chemical structure, and optical properties through TEM, XRD, FT-IR, XPS, UV–vis absorption spectrum, and photoluminescence spectra. And the quantum yield of CQDs was up to 52.64%. It was also analyzed in the real sample, demonstrating the feasibility and reliability of detecting Fe 3+ and Cys in the real sample. Furthermore, CQDs can also be used as fluorescent ink for information anti-counterfeiting due to their excellent fluorescent properties.