Determination of antibiotics in liquids by an amperometric sensor modified with a molecularly imprinted polymer

Amperometric sensors coated with MIPs were created for the determination of cefazolin sodium (Cef), neomycin sulfate (Neo) and sulfanilamide (Sulf) in liquid media with detection limits 1.5 × 10 –6 , 7.2 × 10 –6 , and 4.7 × 10 –6 g/dm 3 , respectively, which are below the maximum permissible concentrations of these antibiotics. The relative standard deviation ( S r ) is less than 4%, which indicates a high accuracy of the determination. The sensors demonstrated high selectivity with an imprinting factors ( IF ) 5.8 – 6.3 for the target compounds and low IF (<1.3) for other antibiotics. The accuracy and precision of MIP-Cef, MIP-Neo, and MIP-Sulf sensors was evaluated in the analysis of model solutions by the recovery test with S r not exceeding 5%, and by the reference methods of spectrophotometry and HPLC. The statistical analysis ( F -test and t -test) did not reveal significant differences, confirming the reliability of the method. The absence of the influence of other antibiotics on the results of Cef, Neo, and Sulf determination using MIP sensors was proved by analyzing model mixtures containing cefotaxime, ceftriaxone, and streptomycin. MIP sensors were tested in the analysis of cow milk: in all samples analysed residual content of all antibiotics (Cef, Neo, and Sulf) was not detected. Thus, the developed MIP sensors possess high sensitivity, selectivity, and accuracy, making them promising for monitoring antibiotic residues in water and food products.