An ultrasensitive analytical strategy for malachite green determination in fish samples based on bright orange-emissive carbon dots

Abstract

Abstract In this work, a novel fluorescence method based on an orange-emissive carbon dots (O-CNDs) was for the first time reported for the rapid and ultrasensitive determination of malachite green (MG). The O-CNDs were simply produced via a one-pot hydrothermal treatment of rhodamine B. The detection mechanism was based on the interaction between O-CNDs and MG, where the fluorescence of O-CNDs was suppressed by MG via a combined effect of inner filter effect (IFE) and dynamic suppressing. Under the optimum sensing conditions, the O-CNDs were found to display rapid reaction time (1.0 min), high selectivity and excellent sensitivity with two linear concentration ranges of 0.01–0.1 and 0.1–10.0 μmol L−1, and the corresponding detection limits were as low as 0.08 and 0.93 nmol L−1, respectively. The developed fluorescence method was successfully applied for the determination of MG in fish samples, including silver carp, blackfish, blunt-snout bream, common carp and grass carp, with satisfactory results; the recoveries were in a range of 96.0–104.8 % and the relative standard deviations (RSDs) below 4.54 %. The results of this study validated the great potential of O-CNDs as an effective fluorescence sensing agent for MG monitoring in aquatic samples.