Application of molecularly imprinted polymers and dual-emission carbon dots hybrid for ratiometric determination of chloramphenicol in milk

Chloramphenicol (CLP) is a veterinary antibiotic that has been banned due to its severe side effects but it is still illegally used in animal husbandry. In this work, the fabrication of simple, fast-response and highly selective ratiometric probe for sensitive visual detection of CLP antibiotic at trace levels in both indoor and outdoor is reported. For the construction of the ratiometric fluorescence probe (mMIP@YBCDs), two kinds of different carbon dots with yellow emission (Y/CDs, 560 nm) and blue emission carbon dots (B/CDs, 440 nm) were used as target sensitive and as reference dyes respectively. Besides, molecularly imprinted mesoporous silica was used as a recognized part of the probe. Upon the addition of different concentrations of CLP, the fluorescence of Y/CDs was quenched significantly while the fluorescence intensity of B/CDs stayed constant which was accompanied by gradual fluorescence color change from yellow-to-blue. The ratiometric probe has a linear response in the range of 0.1–3 μgL⁻¹ with a detection limit 0.035 μgL⁻¹. The practicality of the ratiometric method was validated by the quantification of CLP in milk samples.