مشخصات پژوهش

Antibiotics residues in animal derived food products are a great concern for public health. The major risk associated with this problem is drug resistance in pathogenic bacteria in consumers. One of the mostly used antibiotics for chicken before slaughter is tetracycline. Herein, a ratiometric fluorescent probe was designed based on new kind of quantum dots which is synthesized on the base of sulfur and Zn under the alkaline situation and reflux, called SDZn Quantum dot. The synthesized quantum dot proved the higher fluorescence intensity in comparison with lone sulfur quantum dot. Tetracycline quenched the enhanced fluorescence intensity at 505 nm which is caused by the interaction of 8-Hydroxyquinoline and SDZn. This fluorescence intensity is higher than the synthesized SDZn with a red shift to the higher wavelength. The fluorescence intensity of SDZn at 450 nm was not influenced by tetracycline, hence, the indirect method as ratiometric measurements were applied for the quantification. The fluorescence color of SDZn changed from blue to light green with increasing tetracycline concentration, which was applied for visual semi-quantitative detection of tetracycline. The suggested method was linear in the range from 1-1000 ppb with correlation coefficient of 0.99. Moreover, the method was used to detect tetracycline in chicken breast and tigh, chicken liver and egg and the recoveries were about 95.0%-103%. The method was accurate, sensitive, and showed good application potential in on-site detection of tetracycline in food samples. The trend exhibited that the eggs contained the greatest tetracycline concentration, followed by the liver, then the breast and last ly, the tigh. It results that not all muscle tissues incorporate antibiotics at the same concentrations in which the breast hold more antibiotics than the thigh. Since, the liver and the kidney are the major storage and excretory organs for tetracycline and are parenchymatous in nature, the higher amount of