A strong blue fluorescent nanoprobe based on Mg/N co-doped carbon dots coupled with molecularly imprinted polymer for ultrasensitive and highly selective detection of tetracycline in animal-derived foods

Tetracycline (TC) plays a considerable role in the fight against microbial diseases. However, over-use of TC can produce serious harmful effects on humans and even may lead to drug tolerance. Herein, we developed a novel sensitive fluorescent nanosensor based on the encapsulation of magnesium and nitrogen co-doped carbon dots (Mg,N-CDs) into molecularly imprinted polymer (Mg,N-CDs@MIP), which can be utilized for the specific recognition and ultrasensitive detection of TC in animal-derived foods. The high luminescent carbon dots with a maximum emission wavelength of 455 nm under 350 nm excitation and a 33.05 % quantum yield were firstly synthesized using the Mg/N co-doped fluorescence-enhanced strategy, and the introduction of Mg,N-CDs as a signal tag can significantly enhance the sensitivity of fluorescent sensor. Then, via a facile and efficient one-pot reaction, the Mg,N-CDs@MIP was obtained. The resulting Mg,N-CDs@MIP not only displayed superior optical stability and good reusability, but also exhibited higher specificity and selectivity to TC compared with non imprinted polymer (Mg,N-CDs@NIP) and Mg,N-CDs. The developed sensor was applied for determination of TC, and its fluorescence intensity was linearly quenched with the increasing concentration of TC from 5-100 ng mL(-1) with a detection limit of 0.79 ng mL(-1). Additionally, the proposed sensor was utilized for trace analysis of TC in complex foods, and the satisfactory results obtained were consistent with those obtained by HPLC.