Development of selective electrodes for ciprofloxacin and gentamicin antibiotics

Antibiotics are biological sourced or synthetically obtained drugs that are of great importance for human and animal health, used in the treatment of bacterial infectious diseases. However, their effect strength is decreasing due to the bacterial resistance that becomes widespread day by day. Misuse of antibacterial agents by humans; apart from the treatment and prevention of diseases in animals, its use for accelerating its development, increasing the yield, improving food quality has led to an increase in antibiotic resistant bacteria strains. Control of antibiotic residues in biological fluids, tissues, nutrients such as meat, milk and honey is extremely important. For this reason, fast, sensitive, cheap and simple determination methods are needed in which the residual antibiotic level can be easily determined. In the scope of the thesis, simple, fast, low cost voltammetric sensors have been developed for the determination of Ciprofloxacin and Gentamicin. In this context, the glassy carbon electrode was modified using the cyclic voltammetry method. Electrochemical behavior of Ciprofloxacin and Gentamicin antibiotics were investigated by square wave stripping voltammetry method. Within the scope of the thesis, one method for Ciprofloxacin and two different methods for Gentamicin have been developed. Determination of Ciprofloxacin by using glassy carbon electrode modified with 2-Thiophene methanol; It was performed in the 0.1-200 µM linear range, with the 7 nM detection limit. In the first method, Gentamicin determination was carried out by using glassy carbon electrode modified using a combination of 3-methyl thiophene and 3-thiophene carboxylic acid by detection limit 0.039 mM in the linear range of 0.05-4.00 mM. In the second method; determination of Gentamicin was carried out using glassy carbon electrode modified with the combination of β-cyclodextrin and p-toluene sulfonic acid by a limit of 0.048 mM in the linear range of 0.06-3.50 mM. Analytical applications of the developed methods were made in synthetic urine and their recovery efficiencies were calculated.