Application of spectrophotometric method for antibiotic Cefotaxime detection in a model solution

The number of studies on the detection of antibiotics in urban wastewater and in surface waterbodies is increasing every year, as the increase of antibiotic-resistance of microorganisms is one of the most urgent public health problems. This paper presents the results of study on the detection of the antibiotic Cefotaxime (CFX) in model solutions using the spectrophotometric method. In several series of experiments we determined the minimal CFX concentrations in the model solutions, which can be detected with the spectrophotometer PE-5400 UV. The optical density peak in the ultraviolet range at 300 nm is established. The shift of absorption spectrum from 300 to 280 nm in the model solution samples with increasing storage time of the solution was fixed. We determined the CFX peculiarities: increase of optical density peak in samples at pH shift to acidic medium, especially at pH values from 0.2 to 2.0 as well as reduction of the optical density peak with minimum pH values from 6.0 to 6.4 in the wavelength range from 280 to 300 nm. The effect of metal ions added to the model solution of CFX is considered in detail. The results of two series of experiments are presented, in which the possibility of complex compounds with Al3+, Zn2+, Cu2+, Pb2+ formation was determined by changing the concentration ratios of CFX and metal ions. There was an increase in optical density in samples with Zn2+, Cu2+, Pb2+ with increasing in metal ions content. In model solutions with Al3+ and Fe3+ there was no change in optical density. The obtained values of optical density and absorption spectra of CFX model solution can be used when developing methods of antibiotic detection in various media, including urban wastewater.