Ultrasensitive Resonance Scattering (RS) Spectral Detection for Trace Tetracycline in Milk Using Aptamer-Coated Nanogold (ACNG) as a Catalyst

This paper reports an ultrasensitive resonance scattering (RS) method to detect tetracycline (TET) in milk based on the competition of aptamers between nanogold and TET, aggregation of naked nanogold, nanocatalytic Fehling reaction, and RS signals of catalytic product Cu2O cubic. The detection principle was confirmed by the nanoparticle size analyzer (NANOS), scanning electron microscopy (SEM), and X-ray diffraction (XRD). The variations of RS intensity had good linear correlation with TET concentrations, and the limit of detection was calculated as 11.6 nM. The proposed method was successfully applied for analysis of TET in milk, with total recoveries ranging from 105 to 109%.