In-situ growth of cobalt nanoparticles for naked-eye determination of tetracyclines in water, milk, and honey

Abstract This study describes the in-situ growth of cobalt nanoparticles (Co NPs) to a naked-eye determination of tetracycline antibiotics in the water, honey, and milk samples as a colorimetric method. Tetracycline antibiotics bonded cobalt NPs (CoNPs-TCs) are performed light green to yellow color with high UV–vis absorbance at lambda maximum of 400 nm. Cobalt nanoparticles bonded tetracycline were characterized by using UV–vis spectroscopy, Fourier transforms infrared spectroscopy (FT-IR), transmission electron microscopy (TEM), and field-emission scanning electron microscopy (FE-SEM). Effective parameters of the method, such as solution pH (∼8.5), reaction time (3 min), temperature (25 °C), and cobalt concentration (20 μg mL−1) were studied. Analytical validation is performed that the limit of determination 0.21–1.09 μg mL−1 and the limit of quantification was 0.73–3.88 μg mL−1 with a matrix match linear dynamic range from 1 to 100 μg mL−1 for tetracyclines in all water, milk, and honey samples. The accuracy and precision of the method were evaluated with real samples recovery (80–108 %, ±5) and precision (intraday, 0.73–3.75 %, n = 3 and interday, 2.01–4.82 %, n = 9), respectively. This method provides a rapid, simple, and inexpensive detection with acceptable sensitivity.