Efficient fabrication of ratiometric fluorescence imprinting sensors based on organic-inorganic composite materials and highly sensitive detection of oxytetracycline in milk

Ratiometric fluorescence imprinting sensors (GQDs/[email protected]) were successfully constructed by precipitation polymerization method for the recognition and detection of oxytetracycline (OTC) in milk samples. GQDs/[email protected] were characterized by scanning electron microscope (SEM), transmission electron microscope (TEM), fourier transform infrared (FT-IR), thermal gravity analysis (TGA), UV–visible spectroscopy (UV–vis) and X-ray photoelectron spectroscopy (XPS) techniques. A satisfying linear relationship under 0–80 μM OTC concentration (R2 = 0.99699) was exhibited. High sensitivity was showed with the limit of detection of 3.5 nM and high recovery ranged from 99.93% to 100.20%. In addition, the selectivity of GQDs/[email protected] to OTC was well comparing with other antibiotics. With the injection of different concentrations of OTC, the fluorescent color change of GQDs/[email protected] under the 365 nm UV lamp further verified that GQDs/[email protected] were used successfully for the visual detection to OTC in milk samples.