Fluorescent detection of tetracycline in foods based on carbon dots derived from natural red beet pigment

As tetracycline (TET) residue does great harm to human health, it is urgently required to quantify it in animal-derived foods. In this paper, a fluorescent detection probe was synthesized by natural red beet pigment via one-pot hydrothermal method. The red beet pigment carbon dots (RBP-CDs) were evenly dispersed in water with an average diameter of 4.66 nm, and their surface were rich of amino, carboxyl and hydroxyl groups. TET was able to quench the fluorescence of RBP-CDs within 5 min owing to inner filter effect (IFE) and photo-induced electron transfer (PET), and the quenching rate had good linear responses with the concentration of TET in the linear range of 0.5–30 μM and 30–90 μM, respectively. The detection limit was calculated to be 0.36 μM. Moreover, RBP-CDs had a good TET detection performance in food samples with complicated matrix, such as milk, egg and chicken. Due to its safe and easy synthesis procedure, good selectivity and high sensitivity, RBP-CDs will be put to wide use as a environment-friendly and rapid fluorescent probe in TET detection.