Measurement of concentrations of veterinary antibiotics in natural environments using spectral methods

The uncontrolled spread of antibiotics in wastewater and natural environments currently poses a serious environmental threat in all countries. Therefore, the development of rapid methods for detecting antibiotics in natural environments is extremely relevant. The work is devoted to the study of the spectral characteristics of three veterinary antibiotics (tylosin, tetracycline, ciprofloxacin) of different concentrations in the presence of organic substances of natural origin or by-products of animal husbandry. All three antibiotics have absorption bands in the UV region, which were isolated by mathematical processing against the background of a wide absorption spectrum of organic matter in water, soil or organic fertilizers, monotonically decreasing with increasing wavelength. The antibiotic concentration was determined by the area of the absorption band or absorbance value at a fixed wavelength using relevant calibration dependencies. Fluorescence spectroscopy was also used to monitor low concentrations of ciprofloxacin, less than 5 mg/l. The emission band of ciprofloxacin partially overlaps with the fluorescence band of organic matter in water and soil, so to isolate the contribution of this antibiotic to the spectra, synchronous fluorescence spectra with a constant difference in excitation and recording wavelengths were measured. In this case, the antibiotic concentration was determined by the area of the synchronous fluorescence spectrum band in the UV range, in the region of the absorption band of this compound.