Detection of Chlortetracycline Residues in pork Using Silver Nanoparticle Surface-Enhanced Fluorescence of Eu(III)-Chlortetracycline Complexes

Abstract Chlortetracycline (CTC) can form a stable complex with europium ion (Eu(III)), and the surface-enhanced fluorescence with silver nanoparticles (AgNPs) will produce the strong fluorescence in solution phase. When emulsifier OP-10 is added into the above solution phase, the fluorescence intensity of the complex can be further enhanced. In this research, the above mechanism was applied to detect CTC residues in pork. The pH values of pork extract which were extracted by Na2EDTA-Mcllvainc buffer were adjusted by using sodium hydroxide (NaOH) solution, and different concentrations of CTC in pork extract were determined. AgNPs, Eu(III), pork extract containing CTC and emulsifier OP-10 were sequentially mixed, and the fluorescence spectra of the mixture were collected.The comparative experimental methods were used to analyze the effects of AgNPs addition, Eu(III) addition, emulsifier OP-10addition and reaction time on the fluorescence intensity. It is revealed that a good linearity was obtained between the fluorescence intensity of the mixture at 617 nm and the CTC concentrations (0.1~20 mg/L) in pork extract. The linear equation was Y=0.8560X+38.020, and the determination coefficient was 0.9380. The determination coefficient between the actual value and the predictive value for the prediction samples was 0.9960, and the root mean square error (RMSEP) was 1.7869 mg/L. The results showed the experimental method, in which AgNPs and emulsifier OP-10 were used to enhance the fluorescence of Eu(III) and CTC complexes, could meet the demands of the rapid detection of CTC residues in pork.