A Selective Detection of Tetracycline in Animal-Derived Food Samples Using Carbon Quantum Dots as a Fluorescent Eye

We all are surrounded by millions of bacteria, and antibiotics are the only medicine that exists on the Earth to protect us from the thousands of bacterial infections. However, excess consumption of these antibiotics has accelerated the bacterial resistance process. The resistive bacteria then spread and grew exponentially and created several health problems. So, a system is necessarily required that smartly detects the presence of antibiotics in the contaminated samples. Here in this work, a carbon quantum dots (CQDs) based fluorescence resonance energy transfer (FRET) "Turn-Off" sensor was developed for tetracycline (Tetra) detection in animal-derived food samples. The highly fluorescent CQDs have average particle size of around 1.80 ± 0.435 nm were synthesized using pyrolysis method. Here, CQDs-Tetra form a FRET pair, and the emission intensity of CQDs reduced to 57. 3% in the presence of Tetra due to the transfer of energy from donor (CQDs) to acceptor (Tetra). Further, analyzing the lifetime decay of CQDs, which changed from 9.43 ns to 8.89 ns with addition of Tetra, confirms the FRET quenching mechanism. The sensor show the linear response with Tetra concentration varies as 0.05–100 μM with a limit of detection 10.47 nM. The applicability test of the sensor was carried out with real milk and egg samples spiked with standard concentration of Tetra. The test results proved that the sensor could be used as a food monitoring tool.