Carbon dots-based fluorescence microspheres for ultrasensitive detection of malachite green in fish samples

This work made the first attempt to construct a florescence assay based on CDs@FMs (carbon dots-based fluorescence microspheres) for ultrasensitively probing malachite green (MG). Through static quenching and inner filter effect (IFE), the 581-nm emission peak of CDs@FMs could be significantly suppressed by MG. Our results demonstrated two good linear fluorescence responses for MG in the concentration scopes of 0.01–0.1 μM and 0.1–10.0 μM, respectively. Strikingly, the detection limits (LODs) achieved were down to picometer (56.7 pM) and nanometer levels (0.57 nM). Furthermore, this method exhibited good consistency with the HPLC results when applied for quantitatively screening MG from fish samples. Our current research highlights a promising application of CDs@FMs for enhanced MG probing in aquatic products with the merits of rapidity, simplicity, high accuracy and stable signal readout.